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Journal of the Australian Water Association

Volume 33 No 1 February 2006

OPINION AND INDUSTRY NEWS OPINION Addressing People Skills Shortage Critical for Sustainable Water Management and Public Health AWA Sense and Sustainability People and Prices: Dry Issues for the Water Industry

DDay, President, CDavis, CEO, AWA GDufty, St Vincent de Paul

AWA NEWS lncudes special interest groups: Water Education Network, Young Water Professionals, WaterAid Australia, Trade Waste

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CROSSCURRENT Industry News: People, Projects, Meetings

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MEMBERSHIP NEWS AWA new members

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PROFESSIONAL DEVELOPMENT Master Class 'The Price of Water' and other upcoming seminars and events Worry Wastes in Water: Dealing with High Organic & High Salt Loads

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PREVIEW ENVIRO 2006

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NATIONAL EVENT CALENDAR

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TECHNICAL FEATURES I, ·,] indicates the paper hos been peer-reviewed) eWater CRC RESEARCH PROGRAM

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ON-SITE TREATMENT AND DISPOSAL ~ Are On-Site Systems Environmentally Sustainable? Evidence for off-site impacts ranges from sparse ta ambiguous at best. EGardner, AVieritz and CBeal Risk Assessments for Impacts from Non-Sewered Subdivisions Seven basic modelling approaches were identified. AVieritz, PBeavers, EGardner, CBeal, J Doherty, J Baisden and TTurner ~ Tracing Faecal Contributions from On-Site Wastewater Systems Methods fall into three basic categories: biochemical, chemical and molecular. PGeary, VShah, HDunstan, PCoombes and TRothkirch Performance and Auditing of Medium Scale On-Site Wastewater Systems Medium scale plants are often poorly understood by those who own, service, and regulate them. BAsquith, LShelly, J Whitehead 00 Water and Energy Requirements at a Tenanted Research House Data on a 'sustainable' public housing pro;ect. BKele, KHoffman, NOrr, PWolfs, ITomlinson, DJ Midmore ALGAL TOXINS !ml Rapid Screening Test for Microcystin in Water It enables the microcystin toxicity of a sample to be measured as MCLR equivalents. ~ Chlorination of Four Microcystin Variants MCLA is the most difficult microcystin variant to treat. EDUCATION Using Education to your Advantage Tips on engaging your community more effectively.

36

44 48

52 57

ZMoore, CFerguson, VSen, TFlapper

62

LHo, SRinck-Pfeiffer, KCraig, GNewcombe

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GCollier, CCheeseman

70

WATER BUSINESS NEW PRODUCTS AND BUSINESS INFORMATION - SPECIAL FEATURE: PIPELINES

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ADVERTISERS' INDEX

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OUR COVER David Street wetland, O'Connor, ACT: ecologically-friendly retrofitted stormwater treatment, built by community and government, guided by Ian Lawrence of the former CR( for Freshwater Ecology. The new eWater CRC's decision support tools will strongly support integrated urban water management. See page 30.

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Journal of the Australian Water Association ISSN 0310-0367

Volume 33 No l February 2006

AWA WATER JOURNAL MISSION STATEMENT 'To provide a print journal that interests and informs on water matters, Australian and international, covering technological, environmental, economic and social aspects, and to provide a repository of useful refereed papers.' PUBLISH DATES Water Journal is published eight times per year: February, March, May, June, August, September, November and December EDITORIAL BOARD: Chairman: FR Bishop BN Anderson, CDiaper GFinke, GFinlayson, GA Holder, BLabza, MMuntisov, CPorter, FRoddick, GRyan, AGibson EDITORIAL SUBMISSIONS Water Journal invites editorial submissions for: Technical Papers and topical articles, Opinion, News, New Products and Business Information. Acceptance of editorial submissions is subject to editorial board discretion. Email your submissions to one of the following three categories: 1. TECHNICAL PAPERS AND FEATURES Bob Swinton, Technical Editor, Water Journal: bswinton@blgpond.net.au AND http://gemini.econ.umd.edu/wj {Editorial Express) Papers of 3000-4000 words (allowing for graphics); or topical stories of up to 2,000 words. relating to all areas of the water cycle and waler business. Submissions are tabled at monthly editorial board meetings and where appropriate are assigned to referees. Referee comments will be forwarded to the principal author for further action. See box on page 13 for more details. 2. OPINION, INDUSTRY NEWS, PROFESSIONAL DEVELOPMENT Sue Corlette: Marketing Communications Manager, AWA, scorlette@awa.asn.au Articles of l 000 words or less 3. WATER BUSINESS Brian Rault, National Sales & Advertising Manager, Hallmark Editions brian.rault@halledit.com.au Water Business updates readers on new products and associated business news within the water sector. ADVERTISING Brian Rault, National Sales & Advertising Manager, Hallmark Editions Tel: 61 3 8534 5014 {direct), 6138534 5000 {switch), brian.rault@halledit.com.au Advertisements are included as an information service lo readers and are reviewed before publication to ensure relevance to the waler environment and objectives of AWA. SUBSCRIPTIONS Eight issues $85; postage outside Australia additional cost. Contact: Viyada Gow, Membership and Marketing Officer 61 2 9494 9904 Email: vgow@awa.asn.au BACK ISSUES Water Journal back issues are available to AWA members at www.awa.asn.au PUBLISHER Hallmark Editions, PO BOX 84, HAMPTON, VICTORIA 3188 Tel: 61 3 8534 5000 Fax: 61 3 9530 8911 Email: hallmark.editions@halledit.com.au


time. With the package, urban planners and engineers will be able to analyse and assess integrated water management systems in action. I t will help urban water managers in conceptual design, planning and subsequent evaluation, and in considering large capital expenditure p rograms, such as retrofit of new technologies, and planning policy. eWater CRC experts have previously built existing mod els such as MUSIC (with over 400 licensed users) and AquaCycle (see www.toolkit.net.au), WUFS and PURRS - which incorporate engineering, uncertainty theory and economics - and they have been major contributors to current knowledge about the ecological health of urban screams, the management of co ntaminan ts in stormwater, and water-sensitive urban design.

Integrated monitoring and assessment The in-stream outcomes of river management activities are monitored and assessed periodically; e.g. to check for contamination, or to assess river condi tion. A range of monitoring design guidelines already exist (and are widely used), but there is increasing need for help with applying and interpreting chem, and with risk-based assessment and monitoring. The water industry wants more guidance in aspects such as the design of programs that match objectives, the choice of indicators suited to various mo nitoring contexts and purposes, the choice of appropriate sampling d esigns for types of river, geography, climate (upland , estuary, tropical, temperate, etc.), indicators and budgets, and the interpretation and flexible communication of the results co di fferent audiences. The Integrated Mo nitoring and Assessment System (IMAS) that eWater CRC is building is intended to promote the effectiveness and cost-efficiency of mon itoring programs. I t will be relevant to compliance, inventory, target-setting, and long-term monitoring, and will support both new programs and adaptation of on-going programs. The IMAS designers wi ll be combining and interpreting different forms of information such as raw data, modelled data, GIS data, missing data, expert so urces and literature. We wi ll be finding ways of cho osing ' best' distribu tions of sampling sites, times and flow conditions, and indicators appropriate to che aims of a monitoring program. eWater CRC's staff has a history of involvement in monitoring and assessment. For example, several of our scientists were pivotal in writing the

Supporting the Water Industry

existing national guidelines for water quality and for the monitoring of water quality and sediment quality. O chers jointly performed the Ausrralia-wide Assessment of River Condition for che National Land and Water Resources Audie in 200 l, and helped design the Sustainable Rivers Audie that the MurrayDarling Basin Commission is now running throughout che Basin. We are at present refining new sofrware for ranking existing lines of evidence from non-data sources. Industry personnel of the C RC have a breadth of experience in the design and p ractice of on-ground programs, including environmental-flows monitoring; and industry partners have worked over a number of years with scientists now in eWater C RC to develop and con tin ually refine the models underlying AUSRIVAS (the Austral ian river assessment system), which has registered users in government departments, universities and water industry consul tants all over Australia.

Markee forces in the water industry are changing. Water management is now much more in the hands of many small bodies, while water itself is moving from lower to higher-value uses: within rural user groups, and berween rural and urban or other industrial users. There is increased regulation and public scrutiny, as well as increasing uncertainty. To remain in control, managers have an urgen t need to manage with transparency and repeatability, accessing the most accurate data and projections chat can be had. eWacer C RC's decision cools will support that process.

For further information, please visit the eWater CRC web site (www.ewatercrc.com.au), or contact Professor Gary Jones via info@ewatercrc.com.au. • Written by Ann Milligan (eWater CRC, Communications Coordinator) with significant input from the eWater CRC Executive.

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FEBRUARY 2006 35


l ON-SITE TREATMENT The following five papers are abbreviated versions of papers selected from the On-Site '05 Conference, which was reported in Water November, 2005. The full 48 papers are published in Patterson, R.A, and Jones, M.J. (Eds) Performance Assessment for On-site Systems: Proceedings of On-site '05, held in Armidale 27-30 September 2005. Lanfax Laboratories. Armidale ISBN 0-95794382-2 (400 pages) to whom acknowledgement is due. Hard copies can be ordered from the web-site www.lanfaxlabs.com.au/on-site05 at $116, postage included within Australia. Abstracts of the papers are available on the web-site.

ARE ON-SITE SYSTEMS ENVIRONMENTALLY SUSTAINABLE? E Gardner, A Vieritz, C Beal Abstract Septic systems have a mixed reputation both with the Australian public and regulatory authorities. There is a general belief char they are an outdated and substandard means of on-site wastewater treatment. In this paper we explore the evidence for the sustainability of on-site systems using contamination of surface and groundwaters as primary criteria. Overall we show that despite consistent reports of a high (e.g. 2:20%) incidence of fai ling septic trenches, evidence for off-site impacts ranges from sparse to ambiguous at best. To help fill in experimental data gaps we discuss modelling results reported by both o urselves and ochers, char place contaminant exports (in particular N, P and faecal coliforms) in the context of likely export loads from existing land uses and increasing urbanisation.

Keywords Contaminant export, models, bacterial fingerprinting, urbanisation, septics, on-site systems.

Introduction Over one million o n-site wastewater systems have been installed in Australia. The most common form of on-site systems (>80%) is the septic tank-soil absorption system (septic) (O'Keefe 2001). In comparison, about 25% of households in the United States (i.e ~60 million people) use on-site systems, the majority are septics. Non-sewered allotments are considered a permanent and viable alternative to This paper is based on Ted Gardner's keynote address ro the On-sire '05 Conference, Armidale, September 2005. For fu]l derails see the acknowledgement on this page.

36 FEBRUARY 2006

water

reticulated sewerage. Indeed the USEPA (1997) in a report to Congress scared chat "adequately managed decentralised waste water treatment systems are a cost effective and long term option for meeting public health and water quality goals, particularly in less densely populated areas". However, septics have a mixed reputation both with the Australian public and regulatory authorities. There is a general belief that septic systems are an outdated and sub-standard means of on-site wastewater treatment. Studies and surveys have identified poorly performing o n-site systems, with 15% to 40% of septic absorption trenches showing surcharge at lease some of the time, and allotment scale audit information indicating widespread soggy/ponding/surcharging septic absorption trenches and effluent/greywater irrigation areas (see Gardner 2005). Bue what do we find when we look for evidence of off-site impacts?

Evidence for off-site impacts ranges from sparse to ambiguous at best. Evidence for Off Site Impacts Surface water quality studies A limited n umber of surface water quality studies from non sewered catchments have been reported over the last 15 years in Australia. T he early work of Martens and Warner (1991) measured sediment, nutrients and faecal coliform concentrations in streams d raining small catchments south west of Sydney. The catchments included urban areas serviced by reticulated, septic and AWfS (Aerobic Wastewater

Treatments Systems) as well as control catchments which were largely bushland. After fortn ightly sampling over approximately 12 months, Martens and Warner reported that N, P, FC (faecal coliforms) and suspended sediment concentrations followed the order: septic Âť AWfS > sewered Âť bushland. T hey fou nd all parameters decreased d uring wet weather fl ows, presumably by d ilution from stormwater flow from roads and other impervio us surfaces. T heir results supported a contin uous seepage of contaminant (FC, TN and T P) from shallow water tables to streams, rather than episodic failure in extended wet periods. In a more recent water q uality study of 12 catchments near Melbourne, Hatt et al. (2004) reported a highly significant correlation between NO 3-N (concentrations up to 3 mg/L) in streams and catchment septic density (40 ~ 140 systems/km2 i.e. roughly 25,000 to 7,000 m 2 per system) for both baseflow and stormflow. However, TN load (up to 3.5 kg/ha/yr) was most strongly correlated with effective (i.e. directly connected) impervious area (range 0 ~ 12%) demonstrating the overriding importance of catchment runoff volumes over stream concen tracions. Hatt et al. also observed chat reduction in N loads is most effectively achieved by reducing the fraction of directly connected impervio us areas, whilst reduction in N concentrations will be most effectively achieved by replacement of septic tank systems. Goonetilleke et al. (2005) included a no nsewered rural residential catchment (2,700 ha) in their study of stormwacer quality from dense urban (160 ha) and forested (650 ha) catchments in the Gold Coast hinterland. W hilst annual runoff fig ures

refereed paper


on-site treatment were not reported, average TN and TP were similar for the forested and rural residential catchments (2 mg/L TN , 0.1 mg/L T P) and substantially less than chose for rhe dense urban (3.6 mg/L TN, 0.2 mg/L TP). As the percentage impervious area for the dense urban was 55% compared with 9% fo r rural residential , it can be safely assumed rhac annual TN and TP loads (kg/ha/year) fo r the sewered urban will be substantially greater chan that for the rural residential catch men c. In contrast Hunter et al. (2001) reported a non-sewered area in the Joh nstone River catchment (Qld) exported up to 72 kg TN/ha/year and 2.4 kg TP/ ha/year, compared with 38 kg TN/ha/year and 6.6 kg TP/ha/year for sugar cane and banana catchments. Hunter et al. observed that the non-sewered residential areas (mainly Malanda) were only <0.5% of the 230,000 ha catchment, yet contributed 4% of TN expo res and 15% of NOrN export. However, Gerricse et al. (1995) reported very d ifferent results for small catchments on the lateritic Darling escarpment east of Perth. They showed char for similar N inpu ts per hectare, N levels in the streams drai ning unsewered areas of different

housing densities were much less (maximum of0.55 mg/L NOr N) than N in streams draining the agriculture dominated catchments (2.3 mg/L NOr N) . Taken overall, chis limited body of experimental evidence would suggest that sewered areas with higher housing densities and larger proportion of impervious surfaces will usually expo rt more N and P, and possibly suspended solids, per hectare than non-sewered rural residential areas.

Modelling studies determining allowable allohnent area Demonstrating the effects of multiple land uses in a catchment on stream water q uality is very difficult to investigate experimentally due to a range of interacting facto rs. In such situations modelling becomes an attractive tool and a number of studies have invescigared "allowable allotment area" for no n-sewered subdivisions using the predicted average concentratio n of nutrients in the receivi ng water as the perfo rmance criteria. Edminston (1997), Kinhill (1997) and Jelliffe (1 998) used similar modelling approaches (AQUALM or a similar type of model) char combined nucrienc export from

a given percentage of fail ing septic trenches with dilution from runoff from the surrounding land surfaces including impervious (roads and roofs), residential pervious (e.g. gardens) and residential grasslands. The recommendations are similar from all three studies and suggest that septic systems require allotments of 4,000-6,000m 2 if predicted receiving water quali ty is nor to exceed ANZECC (1992) levels of 0.5 mg/L for N and 0.05 mg/L for

P. This recommended area can be compared with census d ata for SEQ compiled by Beal et al. (2005a) who reported that nonsewered allotment areas ranged from about 10,000m 2 in Pine Rivers Shi re to less than 800m 2 in Noosa Shire. In Caboolcure Shi re, Kinhill (1998) reported average nonsewered allotment areas of 3,000m 2 suggesting chat receiving water quality may be ad versely impacted by the 12,500 on-site systems (9,000 of which are septics).

Modelling studies determining the relative impact of rural residential development and urbanisation Both Edminston (1997) and Kinhill (1998) commenced chat the act of urbanisation was

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refereed paper

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FEBRUARY 2006 37


on-site treatment Table 1. Comparison of the effect of allotment density on the annua l expo rt loads calculated using the MUSIC model. A lso shown are the N , P a nd faecal coliform export loads calculated for non-sewered areas in Pine Rivers Shire, Queensland. Allotment Size m2

Impervious %

Runoff %

TN kg/ ha/yr

TP kg/ ha/ yr

FC cfu/ ha/ yr

High Density Urban Medium Density Urban Traditional Urban Peri-urban

228 500 700 1600

68% 47% 42% 14%

1.47 X 1OI I

5000

4%

17 12 11 7 5

3 2 2

Rural Residential Non-sewered Area in Pi ne Rivers Shire (6600 ha)

70% 56% 53% 34% 27%

9000

N/A

N/A

3

0.02

7.7x109

Development Type

likely to have a greater effect on water quality than the type of sewerage system installed. T h is suggestion is explored in Table 1 where the urban water quality model MUSIC (Fletcher et al. 2001) was used to investigate rhe effect of urbanisation on nutrient (and faecal coliform) export loads, and co compare these with export loads calculated for the on-site sewerage systems in the Pine Rivers Sh ire (Gardner et al. 2005). The MUSIC model allowed the disaggregation of each hypothetical development into road, roof and paved (all impervious) and urban garden and open space (both pervio us). Each land surface had a dry weather and wee weather event mean concen tration (EMC) ofN, P and FC associated with it. Table 1 shows that as impervious areas d ecrease from 68% in high density u rban to 4% in rural residential catchments, che export of N, P and FC decreases from 17, 3 and 10 11 kg/ha (or cfu/ ha) to 5, 1 and 107 respectively supporting rhe general thrust of modelling predictions by Edminston (1997) and Kinhill (1 998). The main reasons for the reduced export loads are the reduction in rainfall runoff (27% for rural residential compared to 70% for high d ensiry urban) and rhe reduction in EMC (2.1 mg/L TN fo r paved, road and roof vs. 0.1 mg/L for urban pervious). Also shown in Table 1 is rhe export from the 7,000 on-site systems in rhe Pine Rivers Shire calculated using mass balance p rinciples (from Gardner et al. 2005). Ir is clear chat with the excep tion of FC, both N and P exports are consid erably less than char due to the residential development itself. The high FC numbers are however an issue as they are human sourced (the majority from surcharging septic trenches) and are likely to have a high concentration of disease-causing pathogenic organisms, both viral and bacterial, compared with FC in urban stormwater runoff.

38 FEBRUARY 2006

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Will aerobic sewerage system reduce contaminant export? Some modelling results The general move towards installing aerobic sewage treatment systems (AWTS) will u nd oubtedly produce a better quality effluent in terms of BOD 5, TSS and FC, bur they leave the N and P concentrations largely unchanged (~ 70% of sep tic ran k concentrations, Gardner et al. 1997). The export from dedicated on site effluent irrigation areas depends o n soil type, climate, vegetation type, crop agronomy (e.g. cut and cart) and of course the area itself. MEDLI (Gardner and Davis 1998) was used to explore the likely export ofN, P and FC from a 200m2 effluent irrigation area in Pine Rivers Shire. The AWTS results were simulated for 12 years (1990-200 1) on a low permeability subsoil (Ks ~5 mm/day) growing "cu t and cart" grass. When scaled up to a suburban density (::::1.5 lots per ha, or 7,000 m 2 per system) the potential runoff of N is small at 1.5 kg N/ha/year, wh ilst runoff of P is about 0.15 kg P/ha/year. Deep drainage loss of N is substantial at 6.5 kg/ha/year, whilst rhe FC in runoff was a very substantial 2 x 10 8 cfu/ha/year. In comparison, from septic dominated areas rhe potential losses are a similar 6 kg N/ha/year though a much larger 3.6 x 10 10 cfu/ ha/year (Neumann et al. 2004). C learly irrigation areas for AWTS have the potential to export substan tial amounts of N and FC, and should be explicitly considered in any catchment scale monitoring.

Mea surement of faecal coliforms in streams draining non-sewered areas Considering chat FC numbers in septic rank effluent are of the order of 10 9 cfu/L whilst septic effluent TN is of the order of 100 mg/L, it is nor surprising chat FC have often been used as evidence for off-site impacts of no n-sewered areas. For example, Beard et al. (1994) in a fortnightly sampling of FC in rivers d rain ing fo u r towns in coastal NSW reported that the

4.54 X 4. 21 X 2.34 X 1.68 X

109 109 107 107

increase in FC/1,000 people as the river passed th rough each town was 10 to 20 times greater in septic dominated towns compared with sewered towns. Ocher stud ies in the Coffs H arbou r area (CHCC 1991) have implicated catchments with onsite systems as major exporters of FC compared with a rural and an urban sewered catchment. Over rwo months, the geometric mean for the septic catchment was 1,250 cfu/ 100 mL compared with c. 200 cfu/ 100 mL for the rural and sewered catch ments. In Q ueensland, Hunter et al. (200 1) reported chat river FC increased almost a hundred-fold during storm events for a non-sewered township (Malanda, 1500 population) reaching values of up to 300 0 cfu/100 mL.

But whose faecal coliform is it anyway? T he difficulty with the preceding scream water quality data is its ambiguity. FC are ubiquitous to warm blooded animals and can be sourced from herbivores (e.g. cattle) and dogs as well as h umans. Three relatively common tech n iques used to identify hu man sources are antibiotic resistance profiles of faecal enterococci (Wiggins 1996); biochemical fingerp rinting of E. coli and Enterococcus (Ahmed et al. 2005) and faecal sterol analysis (Leeming et al. 1998). (See Geary et al, chis issue). Ap plication of these source tracing techniq ues can provide some "interesting" results. For example Booker (1999) in a pose-event analysis of the infamous Wallis Lake incidence of 1997 (444 cases of viral food poisoning from eating faecal contaminated oysters - septics were ascribed the blame) reported chat FC levels in the Wallamba River d raining into Wallis Lake were licrle d ifferent before and after rectifying septic system faults in caravan parks and 490 homes. The faecal scerol analyses clearly identified that humans were NOT rhe source of rhe FC measured in the river system, although (hu man) viral contamination of oysters remained a concern.

refereed paper


on-site treatment Table 2. Comparison of evidence for/against substantial denitrificatio n of septic plume N03-N in aquifers. For further details, see Gard ner et al. (2005). Reference

Location

Observation

Gerritse et al. (1995)

Lateritic soil profiles near Perth

Denitrilication of 80% of initial NO3-N occurred within 1Om of a septic trench

Cromer (2001)

Sandy aquifer in Tasman ia

Denitrilication ( >90% initial NO3-N) occurred within 5m of a septic trench

Geary and Davies (2004)

Sandy aquifers in Part Stephens, NSW: groundwater passes through the riparian zone adjacent to a small creek

>95% denitrilication of initial NO3-N of 75mg/ L measured over 5m

Robertson et al. (1991, 1992)

Aquifers in Canada with either high levels of carbon in the aquifer > 90% denitrilication of in itial concentration of sediment, or a carbon rich stream bed. 50 mg/ L NO3-N within 10-70m of travel Sandy aquifer in Florida with septic plume Almost complete denitrification ol 60 mg/L NO 3-N within 20 m of travel

Showing denitrification

Anderson (1999) Pagendam and Rassam (2005)

Beerburrum, SEQ - riparian zone near to ephemeral stream

Den itrilication of bank storage inflow was almost 100%

Whelan and Barrow (1984)

Sandy soils of Perth

No denitrilication. N concentration (in excess of 300 mg/ L TN) was leached essentially unchanged to 6m deep g/w

Robertson et al. (1991)

A course grained sandy aqu ifer in Canada ¡ plume from a septic tank

Little change in 30 mg/L NO3-N over 80m of travel

Showing no denitrification

In contrast, Geary and Davies (2004) used antibiotic resistance profiling co identify char humans were the source of 20-30% of faecal streptococci isolates in the Till igerry Creek catchment which contained 330 septic systems (1 1% at high risk of export) chat drains into the Pore Stephens escuary another important oyster producing area of NSW. A lacer study by Geary et al. (2005) in che same area measured FC levels in excess of 19,000 cfu / 100ml in a tidal drain, and using faecal sterol analysis, identified a 100% human source which they accribured co septic trenches in direct contact with rhe shallow water table. Finally, Ahmed et al. (2005) classified the E.coli and enterococci phenotypes downstream of a small septic dominated subdivision with shallow groundwater in Eudlo Creek, Queensland using che biochemical fingerprinting method. They concluded char I 0-13% of the phenotypes (which numbered in rhe thousands) came from human sources, and were able co use rhe biochemical phenotypes co clearly identi fy rhe individual septics that were exporting faecal bacteria. le would appear char rhe faecal srerols and biochemical fingerprinting are valuable cools co identify rhe "smoking gun" of human export from on-sire systems. H owever, sampling must be event-based as FC export during storm events can be orders of magnitude greater than rhac during baseflow, especially if the source is surcharging septic trenches.

refereed paper

Ground water quality studies - Do septic systems contaminant groundwater?

T he objective of septic absorption trenches is co generate unsacuraced soil conditions beneath the trench co enhance rhe oxidation of N co NOr N, BOD co CO2 and destroy most of the FC and viral pathogens. With 600 co 900 mm of unsaturated soil above the water cable, there is convincing evidence that disso lved organic carbon is reduced by at least an order of magnitude and bacteria/viruses co ncentrations are reduced by 3 co 4 log (see review by Beal et al. 20056). Once the effiuent leachate reaches the groundwater, there is a further nacural disinfection influenced by water temperature, travel time (Yates and Yates 1988) and in some cases strong viral adsorption on aquifer material (e.g. Pang et al. 2003) . Mose Pis transformed into che reactive orthophosphate (PO4-P) (Gardner et al. 1997) which is strongly immobilised in most Australian soils (Gerricse et al. 1995). Given the likely validity of the preceding arguments, NO3-N is the most likely co ntaminant of groundwater underlying non-sewered subdivisions. However the evidence for such contamination (defi ned as NO 3-N ~ l O mg/L) is nor consisrenc, notwithstanding the seminal "septic plume" scudy in Canada by Robertson et al. (199 1). In a review of Australian studies, Whitehead and Geary (2000) noted che elevated levels of N O 3-N in groundwater associated with non-sewered allotments in Victoria (800m 2 lot size). However in a subsequent review of five scudies in NSW

and Tasmania (Whirehead et al. 200 I), they concluded char even with septic densities as high as 900/km 2 - (i.e. lot sizes ca. 1000 111 2) there was no clear association between NOrN levels (and FC numbers) and septic density, nor indeed with the percentage of "failing septic systems" chey measured. This lack of relationship may be due co denicrificacion in che groundwater, often dism issed because of insufficient labile carbon. However, there is an increasing number of studies showing substantial denitrificacion occurs in aquifers (Table 2) . A more derailed review of Australian & USA evidence on groundwater contamination is reported in Beal et al. (20056). Groundwater modelling studies

In the absence of relatively unambiguous experimental data, we curned co modelling ro examine the effects of septic trench density, aquifer dilution and denicrificarion on groundwater contamination, using MODFLOW/MT3D. We assumed a NOrN concentration of77 mg/Lin the leachate calculated from N load per house, effiuent volume loading, and fractional N losses in the septic tank (6%) and leach field (35%) as per the Valiela et al. (1997) scudy. Figure 1 shows the NOr N contours for an unconfined aquifer, 5 m chick, with a dispersivity of 10 m, a typical hydraulic gradient of0.001, hydraulic conductivity of 10 m/day, an effective porosity of O.1 , and two denirrification races (0% and 2%). The septic trench density was either 1 or 4 allormencs per ha (i.e. 2,500 co 10,000 m2).

water

FEBRUARY 2006

39


on-site treatment er ha

B

A 1 mg/L 10 mg/L

.

~~ ~~~ - - ~<, ® ~

~~@

., - ~

Pt3

@

1 mg/L

®€

@® ~

® ~© ©

G>~

+- 300m

D

C

~@

,...,

____.

10 mg/L

1000m

Figure 1. Predicted N O 3-N contours after 5 years in a 5 m thick unconfi ned aqu ifer w ith a dispersivity of 1Om, septic trench den sities o f 1 and 4 allotments per ha, and two denitrification rates. The square defining the septic development is 9 ha. The plumes are coloured to th e 10 mg/L contour line, uncoloured to the 1 mg/ L contour line.

The high NO 3-N leachate concentration of77 mg/Lis quickly diluted by dispersion in the aquifer to values below 10 mg/L within 150 m down gradient from the subd ivision (Fig la) even with nil den icrification. Although reducing septic trench density to 1 allotment per ha reduced the extent of groundwater contamination, a modest deni crifi cacion of 2% was found co be by far che most effective process, reducing both the plume concentrations and travel length substantially (Figs l c&d). The seduction of modelling, of course, is chat one can "twist the knobs" to ones heart's content if there are no validation data to provide a reality check. Such data seem to be largely missing in Australia and until model pred ictions can be calibrated against well-focused field data, the ambiguity ofNO3-N contamination will remain. Some empirical evidence (e.g. Geary 2004) suggests chat aquifer denicrification can be a major loss process especially in riparian groundwater areas. Modelling and measurement in agricultural catchments in SEQ support these findings (Rassam et al. 2005).

Conclusions Considering chat 15% to 40% of septic absorption trenches show surcharge at least some of the time, it would be expected chat off site impacts on stream water quality would be self evident. However the data we have reviewed suggests otherwise, probably due to masking effects from nutrient and FC

40 FE BRUARY 2006 water

export from the impervious zones of an urbanised area (even rural residential). W ith the exception of tracing studies by Ahmed et al. (2005), Geary et al. (2005) and Carroll et al. (2005), there is licde evidence for a "smoking gun" fro m nonsewered areas, despite widespread synoptic water quality monitoring by many local authorities and catchment management aut horities. H owever absence of evidence is not evidence ofabsence, especially if the best source identification protocols, which include faecal bacteria fingerprinting, faecal sterols and possibly natural isotopes (e.g. Nl5) have not been employed. These techniques are still in the research domain and some more well-designed monitoring projects in streams d raining non-sewered areas are required before we can move forward with any certainty. Evidence for groundwater contamination, largely by nitrace-N, is also ambiguous probably d ue to a combination of variable housing density, aquifer d ilution, and denicrification. I ndeed aquifer denitrificacion is likely to be more widespread than commonly thought, especially in the riparian zone. Groundwater modelling can help provide insight into the relative importance of the various processes, and help guide the location and experimental design of subsequent monitoring studies (e.g. Rassam et al. 2005). T he unsaturated zone beneath the septic trench is essential for the oxidation, immobilisation and/or destruction of n utrients or pathogens. Shallow water

tables (e.g. <90cm to trench bottom) are the enemy to well fu nctioning septic systems, and absorption trenches located in such areas should be removed. Co mmon sense suggests that su b-standard systems need to be properly maintained and even repaired, but d o we have the community will to enforce chis? Ratepayers and politicians have yet to be convinced of any substantial adverse impacts . However chis is not surprising given that the evidence fo r off site impacts is anything but clear cut. Is chis due to the large allotment size (e.g. 2:3,000m 2) of many non-sewered areas? Conversely are small allotments (e.g. 8001,000 m 2 ) prime candidates fo r export of sewage sourced contaminants? H ow can we cease apart the urbanisation export loads from those d ue to the type of sewerage system installed? We fully support the allotment scale audit/monitoring initiatives by councils in SEQ (described in Gardner 2005) - the results are likely to raise community awareness of the size of allotment scale problems and lead to professional system maintenance and consistent regulatory enforcement of failing systems.

Acknowledgments We are grateful to Anne Tobin whose librarianship skills were invaluable during chis study.

References Ahmed, W, Neller, R & Kacouli, M, 2005, ' Host species specific metabolic fingerprint data base for Enterococci and Escherichia coli and its implications co identify sources

refereed paper


on-site treatment of faecal contaminat ion in surface waters,

Applied and Environmental Microbiology, 7 I , pp.4461-4468. ANZECC (1992). ANZECC Water Q uality Guidelines for Fresh and Marine Waters, Australian and New Zealand Environment Conservation Council, November 1992. Beal , C., Gardner, E., Christ iansen, C., & Beavers, P., 2005a, 'A review of on-site wastewater practices in south-east Q ueensland', Water, June 2005, pp 69-74. Beal, C D , Gardner, EA & Menzies, NW, 20056, ' Process, performance and pollution potential: A review of septic tank- soil absorption systems', Australian journal of Soil Research, 43, pp. 78 1-802. Beard J, Sladden T & Sullivan G, I 994, ' Effiuent disposal and waterway contamination', Environmental Health Review Australia August/O ctober, pp.1 5-18. Booker, B l 999, 'The source of faecal coliforms in Wallis Lake, NSW' , Annual Coastal Conference Proceedings, Forster, NSW Coastal Council, pp.38-5 l. Carroll S., H argreaves M ., Goonetilleke A., 2005, Sourci ng faecal pollution fro m onsite wastewater treatment systems in surface waters using antibiotic resistance analysis. Journal ofApplied Microbiology, 99, pp 47 1482 Coffs Harbour City Council, 199 l, 'A discussion paper on rural residential subdi-

vision and on-site effiu ent disposal', August 1991, 18pp. Edmiston, P , 1997, 'Onsite effiuent disposal and water quality in Noosa Shire - a planning scheme reuse project', Noosa Council, February 1997. Fletcher, T.D. , Wong, T .H .F. , Duncan, H.P., Coleman, J.R. & Jenkins, G.A. 2001 , ' Managing impacts of urbanisation on receiving waters: A decision-making framework', Proceedings of the 3rd

Australian Stream Management Conference, Brisbane, 27-29 August, 2001, pp. 217223. Gardner T , 2005, Keynote: Are on-site systems environmentally sustainable? Can monitoring provide rhe answer? Proceedings

of On-site '05 Conference: Performance assessment fa r on-site systems, Un iversity of New England, Asmidale, NSW, R. Patterson & M. Jones (eds) . (Lanfax Laboratories) . Gardner EA & Davies R (Eds) ( 1998) . MEDL! Version 1.2 Technical Manual, Department of Primary Industries, Q ueensland. Gardner T, Geary P & Gordon I , I 997, Ecological sustainability and on-site effi uent treatment systems. Australian journal ofEnvironmental Management, 4, pp. 144-156. Gardner, T , Ne umann , L, Claridge, J, Vieritz, A, Baisden , J, Beal, C, Beavers, P,

Christiansen, C, 2005 , 'Contaminant mass balance of a non-sewered area in SEQ',

Proceedings ofOn-site '05 Conference: Performance assessment far on-site systems, U niversity of New England, Asmidale, NSW, R. Patterson & M. Jones (eds) . (Lanfax Laboratories). Geary, PM, 2004, On-site Domestic System Effiuent Tracing in a Coastal Catchment. 10th Nat ional Symposium on Individual and Small Com munity Sewage Systems Proceedings, Sacrame nto, ASAE, pp722732. Geary, P, Shah,V, D unstan, H, Coombes, P & Rothkirch , T , 2005, Bacterial source tracing methods ro dist ingu ish between faeca l contam inations from on-site wastewat er systems', Proceedings of On-site

'05 Conference: Performance assessment far on-site systems, University of New England, Armidale, NSW, R. Patterson & M. Jones (eds). (Lanfax Laboratories) G erritse RG, Adeney JA, Dimmock GM & Oliver YM, 1995, Retention of nitrate and phosphate in soils of the Darling Plateau in Western Aust ralia: Implications for domest ic septic tank systems. Australian Journal ofSoil Research, 33, pp. 353-367. Goonerilleke A, T homas E, G inn S & G ilbe rt D, 2005, ' Understanding the role of land use in urban stormwater quality management' . journal ofEnvironmental Management, 74, pp. 3 1-42.


on-site treatment Hatt BE, Fletcher TD, Walsh CJ, Taylor SL (2004) The influence oFurban density and drainage infrastructure on the concentrat ion and loads of pollutants in small streams. Environmental Management 34 , pp. 11 2-124. H unter, H, Sologinkin, S, & Choy, S, 2001, Water management in the Johnston Basin, Report on NHT Project 952194, DNR&M 200 1. Jelliffe PA, 1998, ' Predicting scormwacer quality from unsewered development',

Waterfall (Journal of the Storm water Industry Association) 9, pp.19-24 . Kinhill, 1997, 'Caboolcure rural residential effiuent t reatment and disposal study', Prepared foe Caboolture Shire Council, Queensland, Kinh ill Pry. Ltd., Brisbane. Leeming, R, Ball, A, Ashbolc, NJ & Nichols, PD, 1996, 'Using faecal scerols from humans and animals co distingu ish faecal pollution in receiving waters', Water Research, 30, pp. 2893-2900. Martens OM & Warner RF, 1991 , 'Evaluation of the environmental impacts of aerated wastewater treatment systems.' Department of Geography, University of Sydney, NSW, Australia, May 1991. Neumann, L., Gardner, T., C laridge, J. , Vieritz, A., Baisden, J ., Beal, C., Beavers, P. & C hristiansen, C. 2004, 'Audit of non

sewered subdivisions in south-east Queensland - Task 4. Initial mass balance assessment of

non sewered areas; Report prepared for Moreton Bay Waterways and Catchment Partnership, October 2004. O'Keefe N, 2001, 'Accreditation oF on-site wastewater creacment systems - installation & maintenance personnel', Proceedings of On-site 'OJ Conference, UNE, Armidale, NSW (R. Patterson & M. Jones eds), pp. 295-299. (Lanfax Laboratories). Pang L, C lose M, Goltz M, Sinton L, Davies H , Hall C & Stanton G, 2003, Estimation oF septic tank setback distances based on transport of E. coli and F-RNA phages. Environment International 29, pp. 907-921. Rassam D , Pagendam D & Hunter H, 2005, ' T he Riparian N itrogen Model (RNM) Basic Theory and Conceptualisat ion, Technical Report 05/09 June 2005, CRC fo r Catchment H ydrology and C RC for C oastal Z one, Estuary & Waterway Management. Robenson WO, C herry JA & Sudicky EA, 1991, 'Ground-water contamination from two small septic systems on sand aquife rs', GroundWater 29, pp. 82-92. Valiela, I, Coll ins, G, Kremer, J, Lajcha, K, Geise, M, Seely, B, Brawley, J & Sham, CH, 1997, 'Nitrogen Loading from coastal watersheds co receiving Estuaries: New Method and Application', Ecological Applications, 7(2), pp. 358-380. W h itehead, J, Geary, P & Saunder, M, 200 I, 'Towards a better understanding of

sustainable lot density - evidence from five Australian studies', Proceedings of On-Site 'OJ, University of New England, NSW, R. Patterson & M. Jones (eds), pp.383-390. (Lanfax Laboratories). W hitehead, JH, & Geary, PM, 2000, 'Geocechnical aspects oFdomestic on-site effluent management systems', Australian Journal ofEarth Science, 47, 75-82. W iggins, BA, 1996, 'Discriminate analysis oF antibiotic resistance patterns in faecal Streptococci - A method co d ifferentiate human and animal sources of faecal pollut ion in natural waters', Applied and Environmental Microbiology, 62(1 I), pp. 3997-4002. Yates, MV & Yates, SR, 1988, 'Modeling microbial face in the subsurface environment', Critical Reviews in Environmental Science and Technology, 17, pp. 307-343.

The Authors Ted Gardner (ted.gardner@nrm.qld. gov.au) is a Principal Scientist with the Queensland D epartment of Natural Resources and Mines (NR&M) and an adjunct Assoc. Professor at the U niversity of Queensland. Alison Vieritz is a Research Scientist at NR&M, whilst Cara Beal is associated with the U niversity of Queensland and the Coastal Zone C RC.

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42 FEBRUARY 2006 water

refereed paper


RISK ASSESSMENTS FOR IMPACTS FROM NON-SEWERED SUBDIVISIONS A Vieritz, P Beavers, E Gardner, C Beal, J Doherty, J Baisden, T Turner Abstract The Moreton Bay Waterways and Catchments Partnership commissioned the Q ueensland Department of Natural Resources & Mines to undertake a desktop review of modelling approaches for assessing the risk of nitrogen (N), phosphorus (P) and pathogen contamination of waterways from on-site wastewater systems in preparation for recommending the best approach. Twenty-seven models were reviewed and classified into seven basic approaches, (in order of increasing complexity) Hazard, Empirical, Mass balance, Analytical, Biophysical, Dedicated, and Integrated Systems. The strengths and weaknesses of each modelling approach, the competing methodologies, the scale and details of their predictions and fie ld validation were assessed, considering the data and analytical requirements, applicability to SEQ region and ease of use, and the associated potential costs of application to SEQ.

Keywords: off-site impacts, on-site systems, risk assessment models, modelling, contaminant export, nutrients, pathogens

Introduction Stakeholders in the Moreton Bay Waterways and Catchments Partnership (MBWCP) are concerned about the potential impacts that septic and ocher onsire wastewater systems may be having on local and regional water quality in south east Queensland (SEQ). To date, few investigations in both Australia and overseas have been able to provide conclusive evidence of the water quality pollution to waterways from on-site wastewater systems in relation to the whole of catchment export (Gardner,

This paper is an abbreviated version of the refereed paper presented at the On-sire 05 Conference, Armidale, September 2005. For full derails see the acknowledgement on page 36.

44 FEBRUARY 2006 water

2005). However, the absence of reported problems does not mean there are no problems. It may mean that further monitoring is needed - but systematic event-based monitoring is costly and timeconsuming, especially if there is not a strong likelihood of delivering unambiguous quantitative results. This paper presents the results of a review of risk assessment methods used in Australia and overseas. It forms part of a series of reports on non-sewered subdivisions in SEQ prepared for Healthy Waterways (e.g. Gardner et al., 2005; Beal et al., 2005).

Seven basic modelling approaches were identified. Model Review Methodology Risk, defined by the Australian Standard for Risk Management, is the product of the likelihood of an event occurring and the severity of its consequence. Therefore the focus of this study was on models that could be useful in predicting either of these two components of risk, and which have been (or can be) applied to the assessment of risk of contamination by on-site sewage facil ities. Model reviews by USEP A (2002) and Siegrist et al. (2000) provided an initial basis for model selection. Added to this were Australian approaches and models which could be adapted to on-site sewerage faci lity impact modelling, or which contain useful algorithms for describing off-site pollutant transport.

Risk Assessment Approaches Reviewed We were surprised by the large variety of models and the number that have been developed recently (over one-third were developed within the lase six years). A summary of che models reviewed is given in Table 1. An exhaustive review of all

relevant models is not attempted in this paper (but see Vieritz et al., 2004 for derailed review). Rather, seven basic modell ing approaches were identified. These are: 1. Hazard Models: Hazard models involved a methodology in which the user rates various attributes of a site or region to yield an overall indicator of likelihood of environmental contamination. In some cases, the importance of potential receptors of the contamination is also ranked (a measure of consequence), and the rwo forms of ranki ng, together with geographic separation distance, is used to provide an estimate of risk of environmental contamination from on-site sewage facilities (OSSF) sites. The methodology requires a lot of q ualitative input and hence is useful where quantitative data is scarce. Combined with Geographical Information Systems, they allow the risk mapping to be attempted to identify "hot spots". However, only one hazard model, OSRAS Rev2 (Whitehead et al., 2004), predicts the cumulative risk from OSSFs on the receptor. 2. Empirical Models: Empirical models are developed by fitti ng suitable mathematical relationships to data. These models are very data intensive and are not considered further in this paper. 3. Mass Balance Models: The mass balance methods provide an excellent scoping tool based on the premise that mass of each contaminant is conserved. Partitioning coefficients are used to show how the contaminant mass moves through time and space. Using conservative (but transparent) assumptions about the partitioning coefficients, they indicate the maximum loading of contaminants from a catchment into receiving waters. A weakness of mass balance models is that the output often shows no temporal resolution, representing "average" or "long-term" values. Such predictions are d ifficult to validate without long-term data collection studies. T he mass loading predictions are compared with guideline

refereed paper


on-site treatment Table 1. Overview of models useful for risk assessment of on-site systems. A detailed description of the models is reported in Vieritz et al. (2004) . Modelling Approach Description

Examples

Country & Year of First Release

Scope•

Scale•

Complexity•

Resources•

1. Hazard

DRASTIC Hoover et al.'s model Impact probability approach OSRAS OSRAS Rev2

USA 1987 USA 1998 USA 1999

S3-S4 > 40 ha S4 Sl S3 <= 200 km 2 S3-S4

C2 Cl Cl C2 C2

R2-R3 R2-R3 Rl

QUT Integrated Risk Assessment Model

AUS 2001 AUS 2005+ AUS 2005+

GW GW&SW GW&SW SW SW GW & SW

S3-S4

C2

R2-R3 R2-R3

2. Empirical

SPARROW

USA 1997

SW

S3-S4

C4

R3

3. Mass Balance

Trela & Douglas's model ON-SITE PLANNER Kimsey model Valiela et al's model MANAGE TRENCH 3.0

USA AUS USA USA USA AUS

1978 1996 1997 1997 1997 1999

GW GW GW GW&SW GW

Sl -S2 Sl Sl -S2 S4 S3-S4 Sl

Cl Cl Cl Cl C2 Cl

Rl Rl Rl Rl -R2 R2-R3 Rl

4. Analytical

US EPA VHS model DAM

USA 1989 AUS 2003

GW GW

S3-S4 Sl

C3 C3-C4

Rl-R2 Rl

5. Biophysical

SWMM Jelliffe' s model MEDLI TOPLATS UVQ EMSS for SEQ MUSIC

USA 1971 AUS 1995 AUS 1996 USA 1999 AUS 2000 AUS 2001 AUS 2001

GW&SW SW SW GW&SW SW GW&SW SW

S3 Sl-S2 Sl-S2 S3-S4 Sl -S2 S4 S3-S4

C4 C3 C3 C4 C3 C4 C3

Rl -R2 Rl Rl R2 Rl -R2 R3 Rl-R2

6. Dedicated (groundwater)

MODFLOW MODPATH MT3DMS WINFLOW/WINTRANS

USA 1988 USA 1989 USA 1990 UK 1995

GW GW GW GW

S3-S4 S3-S4 S3-S4 S3-S4

C4 C4 C4 C4

Rl Rl Rl Rl

6. Dedicated (pathogen export)

SEDMOD Tian et ol's model

USA 1996 USA 2002

SW SW

S3-S4 S3-S4

C2 C4

Rl Rl -R2

7. Integrated

BASINS 3.0 (HSPF)

USA 1998

GW&SW

S3-S4

C4

R3

WARMF

USA 2001

GW&SW

S3-S4

C4

R2-R3

R2

*Scope - GW (groundwater}, SW (surface water}. Scale - S 1 (Allotment}, S2 (Subdivision}, S3 (Small catchment} S4 {Large catchment}. Complexity - C 1 (low, spatially lumped, temporally lumped}, C2 (medium, spatially distributed, temporally lumped}, C3 (medium, spatially lumped, temporolly distributed}, C4 {high spatially distributed, temporally distributed}. Resources (Cost and Time to develop data) - R1 (low, =,$1 OK, weeks of work}, R2 {medium, $ 101OOK, months of work}, R3 {high, $100-1OOOK, years of work}. values to ind icate the likelihood of undesirable (contamination ) conseq uences. 4. Analytical Models: Analytical mod els use process theory to provide a relationship between inputs and o utcomes. This relationship {an analytical equation) is directly solved once all the inputs are entered to determine the outcome prediction. Calibration may be needed co d etermine some of che equation co effi cients. Analytical models tend to be limi ted to slowly changing systems {such as groundwater flow) and to systems with constant inputs, and uniform media. Inputs are based on average conditio ns. These mod els may be useful to apply to the part of a system that exhibits these characteristics.

refereed paper

5. Biophysical Models: These m odels also use mass balance, but incorporate system processes more explicitly using physically based or process-based equations, rather chan just partitioning coefficients, and so capture more of the system dynamics. These models are parameter-rich, buc che parameters are often easier co measure being, in principle, measurable physical quantities {although they be difficult to measure at the tern poral and spacial scale needed). They usually have "more knobs to turn" as they simulate more processes. But complexiry usually limits their spatial and temporal resolution. 6. Dedicated Models: Models are available which sim ulate a specific p rocess, such as groundwater flow or pathogen die-off,

using approaches ranging from mass balance to biophysical. Such models may be useful in meeting part of ou r o bjectives.

7. "Whole of system" or Integrated Models: These wide-sco pe mod els are composed of a number of biophysical models wh ich interact to simulate che processes operating across a whole regio n at a high level of detail allowing a wide range of managemen t options to be explored. They usually have user-frienclly fron t-ends and graphical interface so chat communiry representatives can run and re-run the model to explore management strategies, usually once the experts have sec it up. Data requi rements are enormous and these mod els were built in USA co exploit the extensive databases available there. Australia

water

FEBRUARY 2006 45


on-site treatment does not have similar databases at this time and so application of these models largely becomes impractical without an extensive data collection exercise.

Discussion The off-site export p rocess from septic absorption trench and irrigation areas are complex, as is evident by th e large (and growing) number of models that attempt to address this. Ir is important to remember that all models are only simplifications of reality, as was succinctly expressed by rhe well-known industrial statistician George Box when he said, "all

models are wrong but some models are useful". In this review, we sought to provide a basis for choosing a modelling strategy that would be useful and our recommended strategy is described in V ierirz et al. (2004, 200 5) . We also found important knowledge gaps that could be addressed in modelling to improve the identification of high-risk sites. Knowledge gaps include: • How to p redict the impact of pollu tant reactions. What is the fate ofthe pollutants

from absorption trench systems as they enter the groundwater system? How is denitrification in groundwater affected by riparian vegetation? • How to predict when a particular on-site system will fail, how badly it will fa il and if ir can recover again. We also lack some understanding of how fai lu re occurs in efflu ent d isposal fi elds and how nutrients and pathogens are exported. What is the

fate of the surcharge/irrigation area runoff and how is it affected by a rainfall-runoff event? How much of the surcha,gelirrigation runoff re-infiltrates, moves as inter/low, or leaches to the groundwater? Is failure driven largely by organic/solids overloading of absorption trenches? How important are differences in soil hydraulic properties? Is landscape position a good index offailure potential? What is the N balance ofa nonharvested effluent irrigation area? Can we model transport ofdissolved contaminants during overland flow and re-entrainment? • A lack of study of rhe cumulative impacts of on-site sewerage facility on rhe

environment (with rhe exception of groundwater systems e.g. Geary, 200 4).

How does the on-site export load compare with the catchment export? • Basic concentration data. What are the mean concentrations of TSS, TP, TN and faecal coliforms in storm water flows and dry weather flows from pervious on-site sewage surfaces? We need nor have quantitative answers to all these questions, bur we certainly need relative estimates to be able to rare the likelihood and consequences. We also need some sense of scale so char we know whether or not a high value is still acceptable.

Acknowledgments Many thanks to Moreton Bay Waterways and Catchments Partnersh ip (Healthy Waterways) for their support of this study.

The Authors Alison Vieritz (Alison.Vieritz@nrm.qld. gov.au), Ted Gardner, John Baisden and Tony Turner are wirh the Queensland D epartment of Natural Resources & Mines, Indooroopilly. Peter Beavers is Adjunct Professor at Queensland University of Technology, Cara Beal is a PhD candidate at the U niversiry of QLD and Coastal Zone CRC, John Doherty is Principal of Watermark Computing Pry Ltd, Brisbane.

References Australian Standard for Risk Management AS/NZS 4630: 1999. Beal, C., Gardner, E., Christiansen, C., & Beavers, P., 2005, 'A review of on-sire wastewater practices in south-east Queensland, Water, June 2005, pp 69-74. Beal C.D ., Gardner E.A., Vierirz A.M., & Menzies N.W. 2003, 'Can we predict failure of septic rank-soil absorption systems? A review of their hydrology and biogeochemisrry', Proceedings of On-site '03 Conference -

Future directions far on-site systems: Best management practices, Armidale, NSW, RA Patterson (ed), Lanfax Laboratories, pp. 6976. Gardner T., 2005, Keynote: Are on-sire systems environmentally sustainable? Can monitoring provide the answer' Proceedings of On-site '05 Conference: Perfo rmance

assessment for on-sire systems, University of New England, Arm idale, NSW, R. Patterson & M. Jones (eds). (Lanfax Laboratories) . Gardner T. , Neumann L., Claridge J., Viericz A., Baisden J., Beal C., Beavers, P. & Christiansen C. 2005, Contaminant mass balance of a non-sewered area in SEQueensland. Proceedings of On-site '05

Conference - Performance Assessment far Onsite Systems: Regulation, operation and monitoring. 26-30 September 2005, Armidale, RA Patterson and MJ Jones (eds), Lanfax Laboratories, pp 191- 199. Geary P.M . 2004, ' O n-sire domestic system effluent tracing in a coastal catchment',

Tenth National Symposium on Individual and Small Community Sewage Systems. Proceedings of the March 21-24, 2004 Conference, Sacramento, California USA. K.R. Mankin (ed.), pp 722-732. Siegrist R., Tyler E.J., & Jenssen P.O., 2000, 'Design and performance of onsice wastewater soil absorption systems', National

Research Needs Conference Proceedings: Risk Based Decision Making.for Onsite Wastewater Treatment. CA, U.S. EPA and NDWRCDP p. 48. USEPA 2002, Onsite Wastewater Treatment Systems Manual. EPA/625/R-00/008. U.S . Environmental Protection Agency. Vieritz A., Beavers P. , Gardner T., Beal C., Doherty, J., Baisden J., & Turner T. 2004, Risk Assessment Approaches for NonSewered Subdivisions - T ask 2 of the Audie for Non-sewered Areas in South-Easr Queensland. Prepared by DNR&M fo r MBWCP, October 2004, 129pp. Viericz A., Beavers P., Gardner T., Beal C., Doherty, J., Baisden J., & Turner T. 2005, Review of risk assessment approaches for off-sire impacts from non-sewered subdivision, Proceedings of On-site '05 Conference -

Performance Assessmentfar On-site Systems: Regulation, operation and monitoring. 26-30 September 200 5, Armidale. RA Patterson and MJ Jones (eds) , Lanfax Laboratories, pp 375-382. Whitehead, J.H., Barry, M.E., Syme, W.J. & Irvine, R. 2004, 'A large scale pilot study of a GIS based risk assessment system for onsire wastewater management in New South Wales, Australia', Proceedings of Tenth

National Symposium on Individual and Small Community Sewage Systems, March 2 1-24, 2004, Sacramento California, pp 163-171.

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water

refereed paper


TRACING FAECAL CONTRIBUTIONS FROM ON-SITE WASTEWATER SYSTEMS P Geary, V Shah, H Dunstan, P Coombes, T Rothkirch Abstract Small unsewered coastal comm unities which rely on septic tanks and on-site wastewater treatment/disposal on occasions show high concentrations of faecal indicators in drainage waters. However it is not certain whether they are actually the source of recorded contam ination and whether there is any risk to human health. T his paper reviews a number of the tracking methods and summarises the results to date of a continuing project where faecal biomarker methods are used to differentiate between human and herbivore sources of faecal contaminants at a number of selected sites along the north coast ofNSW. Keywords: Bacterial source tracking,

coprostanol, faecal biomarkers, faecal coliforms, faecal sterols

Introduction Australian studies (Brown and Root Services, 200 1) over the last 15 years have demonstrated that a substantial proportion of domestic on-site wastewater management systems perform poorly or fail, but few of these studies have been able to demonstrate any links to adverse impacts on human health and receiving waters. Nevertheless, concerns that failing systems at high densities may contribute to a decline in environmental water quality have prompted major audit surveys of on-site wastewater systems and their performance (Beal et al, 2003). The inability to discern direct linkages between failing systems and widespread contamination is partly d ue to effluent dilution and the difficulties which exist in differentiating effluen t pathways in the field. While standard or common microbiological (bacterial) indicators are used to identify faecal contamination in water, they cannot be used o n their own to distinguish between human contamination and that derived from domestic pets, farm animals, native birds. This paper is an abbreviated version of the refereed paper presented at the O n-sire 05 Conference, Armidale, September 2005. For fu ll derails see the acknowledgement on page 36.

48 FEBRUARY 2006

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Oyster growing waters threatened development.

by faecal contamination from unsewered

Methods have recently been developed which allow such distinctions to be made and so me of these have previo usly been reviewed by Sinton et al. (1998) , Sargeant (1999) and the authors (Shah et al., 2004). T he rapidly developing microbial or bacterial source tracking (BST) techniq ues involve the use of molecular or genetic approaches to identify specific strains of microorganisms in the environment. T he term BST is collectively used for several methods that are being employed to explore the "signature" of faecal indicator bacteria in o rder to detect and distinguish their sources (e.g. humans, animals, birds etc.).

Methods fall into three basic categories: biochemical, chemical and molecular. T hese methods to investigate microbial flora fall into th ree basic categories: biochemical, chemical and molecular.

Biochemical methods are pheno typic in their approach, i.e. they explore unique characteristics of different bacteria. Some prominent biochemical methods are: antibiotic resistance analysis (ARA), carbon source utilisation (CSU), F+ coliphage serotyping, host-specific

indicators (e.g. Enterococcus Jaecalis) and bacteriophage indicators. T hese methods are based on an effect of an o rganism's genes that actively produce a biochemical substance. This biochemical response can then be measured and matched with those produced by o rgan isms from known sources. W ith most approaches, it is necessary to build a library o r database of isolates taken from known faecal sources, so that faecal isolates can be compared against the database. H undreds of isolates from major known faecal sources are needed, as well as a statistical analysis package (such as discriminant analysis) to match the unknown isolates with those from known sources. As a result, studies tend to be large and expensive and validations between methods are difficu lt.

Chemical methods are based on evaluating chemical compounds closely associated with bacteria and domestic wastewater. Some widely used chemical markers are: faecal sterols such as coprostanol, linear alkylbenzenes (LABs), nitrogen and carbon isotope ratios, caffeine, fluorescent whitening agents (FWAs), polycyclic aromatic hydrocarbons (PAHs), detergent compounds, optical fibres and various fragrance materials. Molecular methods examine unique genetic finge rprints of d ifferent species of bacteria.

refereed paper


on-site treatment T h us, these methods are genotypic in their approach. Examples of molecular methods are: host-specific l 6S ribosomal DNA (rDNA) genetic markers, repetitive excragenic palindromic-polymerase chain reaction (REP-PCR), ribotyping, length hererogeneity-PCR (LH-PCR), rerminalresrricrion fragment length polymorph ism (T-RFLP) and pulsed-field gel electrophoresis (PFGE).

Antibiotic Resistance Analysis An example of a phenotypic app roach where differentiation between human and non-human faeca l sou rces is possible is antibiotic resistance analysis. This approach is based on the fact char bacteria from wildlife species are generally lacking in antibiotic resistance, while strai ns from humans and domestic an imals are generally more resistant to antibio tics. Bacterial organisms from diffe ren t known sources are analysed to determine the resistance pattern for several d ifferent types and strengths of antibiotics. Samples are rhen collected from u nknown sources, such as stormwarer drains and watercourses, and rhe bacteria exposed to a similar range of antib iotics. Based on the pattern o f antibiotic response, it is then possible to use discriminant analysis to make valid inferences about the source of the bacteria in the unknown samples. Vario us overseas authors such as Wiggins et al. (1996) and Hagedorn (1999) describe the use of chis app roach ar the catchment scale to d ifferent iate between faecal bacterial sources. Locally Geary and Davies (2003) investigated rhe contribution of on-sire wastewater systems relative to other sources in faecally contaminated estuarine waters with in Port Stephens, NSW.

Faecal Biomarkers Faecal biomarkers, such as srerol compounds, have been successfully used (along with m icrobiological indicators) to help distinguish and estimate con tributions from various sources of faecal contamination. All faecal material contains sterols, and their breakd own products, stanols. The distrib ution of sterols found in faeces, and hence their source-specifi city, is caused by a combination of d iet, an animal's ab ility to synthesise its own srerols, and the conversion of srerols by in testinal m icrobiota in the digestive tract. Distinguishable sterol profiles. i.e. ' fingerpr ints" (Leeming et al., 1998) for humans, herbivores and birds have been used as a tracer of faecal pollution in Australia (Sup rihatin et al. , 2003) and New Zealand (Gilpin et al. , 2002) in marine, es tuarine and freshwat er environments.

refereed paper

Table 1. Project Sample Sites Showi ng Principal Catchment Land uses. Study Site

Land use

Worwiba Creek upstream Bohnock Bridge

Septic unsewered area, mixed grazing land with Nature Reserve

Di ngo Creek @ Belbourie Bridge

Dairyi ng, with mixed grazing land & State Forest

Wallamba River @ Wellers Lane

Dairying, with mixed grazing land

Sarah's Creek at Sarah's Crescent* (downstream)

Septic unsewered area, State Forest

Wilsons River at Primitive Reserve

Pristine, State Forest

Sarah's Creek@ Mile Rd (upstream)

Pristine, State Forest

Morton 's Creek@ Morton's Creek Road near Wauchope

& State Forest

Septic unsewered area, with mixed grazi ng land

Michael Drive Drain*@ Salt Ash

Septic unsewered area

Tilligerry Creek @ Floodgates

Grazing land, with septic unsewered area

Windeyers Creek Bridge near Raymond Terrace

STP discharge, urban areas with mixed grazing land

Myall River @ Markwell

Bird/Poultry, mixed grazing land & State Forest

Coombo Pork Drain* , Wallis Lake

Septic unsewered area

Fry's Creek near Buladeloh

STP discharge, mixed grazing land

Manning River @ Bootawa Dam Offtake

Grazing land, State Forest

â&#x20AC;˘ sites with large numbers of unsewered premises within catchment. Coprostanol constitu tes about 60% of the total sterols in h uman faeces and is produced by biohydrogenation of ch olesterol by anaerobic bacteria in the intestines of hu mans and h igher mammals. It is unaffected by physical factors such as temperature and salinity (Sargeant, 1999). H owever, due to d ifferences in the d iets of herbivores such as cows and sheep, 24ethylcoprostanol is found to be more prevalen t in their excreta than coprostanol. Animals ubiquitous in urban areas, such as dogs and birds, either do not have coprostanol in their faeces, or it is p resent in trace and/or smaller amoun ts, thus p rovid ing a diagnostic dichotomy of presence/absence. A sterol ratio analysis has been proposed by Leeming et al. (1998) to exploit these faecal sterol "fi ngerprints". The co ntribu tion of faeca l matter from the d ifferent sources relative to each other can then be calculated by an examination of the ratio of coprosranol to 24-ethylcoprostanol in human and herbivore faeces. These ratios are then compared to ratios obtained for water samples and proportions calculated. Leeming p roposed the use of a three step ratio analysis to interpret the results of faecal srerol analyses. Typically coprosranol and 24-erhylcoprosranol need to be present in the water sample for furthe r consideration of th e source of faecal contamination. If the ratio of coprosranol to cholesranol is greater than 0.4, then faecal contamination from humans and/or herbivores is likely to be present. If this is the case and the ratio of epicoprosranol to coprosranol is greater than 0 .3, then the

sou rce may be aged human faecal matter such as sewage slud ge. H owever, no study has been successful in estab lishing any direct relationship between faecal srerols and pathogeni c organisms or any consequent threat to public h ealth (Scott et al., 2002). Recent advances in rhe use of this suite of faeca l biomarkers and their ratios have been towards th e development of a decision support system to d ifferentiate between non -point source poll ution inputs by using fin gerp rint graphing methods (Roser et al., 2003). Further work is required on rhe use of these ratios in various catchments with differing land uses and sources of faecal contaminatio n. In this study, rhe application of faeca l biomarker methods to differentiate between human and h erbivore derived sources of contaminants in runoff and the use of these proposed srerol ratios are being investigated.

Study Area and Methods Research fundin g was obtain ed under the Linkage Grant Scheme from the Australian Research Council in 200 3 to collect data o n molecular and microbial markers of human sewage and natural/agricultural contamination in a number of catch ments on the no rth coast of NSW. T he project partners (who are acknowledged later in this paper) used their monitoring data and knowledge of particular "hot spots" to select locations where deteriorating water qual ity is of con cern, shown in Table 1. D erailed information was obtained on previous monitoring and GIS/land-use data has been compiled to be later used to interpret the overall results throughout the project.

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on-site treatment Table 2. Sterol Concentrations Obtained at Selected Water Sampling Sites. Sample ID

A A 8 B C C

D D

Sample Date

29-Mar-05 26-Apr-05 29-Mar-05 26-Apr-05 22-Feb-05 30-Mar-05 25-Feb-05 31 -Mar-05

Epicoprostanol (ng/L)

Caprostonol (ng/L)

Cholesterol (ng/L)

981 .23 1835.86 195.09 18.74

25.47

1570.47 1607.48 0.67 0.00 18.62 17.64 1144286.78

30.05 0.00 0.00 0.00 0.00 0.00 72.14

2443 .49

Cholestanol (ng/L)

11 7.73 259.59 1061600.61 5335.31

contributions from human or animal (herbivore sources) accord ing co the approach previously outlined.

Since November 2004, water samples have been collected both monthly and following significant rainfall events at each of the selected sites by the project partners and forwarded co the U niversity of Newcastle. Analyses including faecal scerol analysis, elemental analysis, bacterial indicator counts and antibiotic resistance analysis are being undertaken. The collected water samples are also analysed by the project partners for faecal coliforms and total coliforms. A database and reporting protocol have been established for reporting results co the p roject partners. In a number of the catchments sampled (refer co Table 1), there are large numbers of unsewered premises.

In che interpretation of the data, knowledge of che principal land uses and likely faecal sources in each catchment is important (Table 1). In Table 2, the samples are identified with che letters A, B, C or D co maintain confidentiality. Ac site A, a wastewater treatment plant discharge is located immediately upstream from che sampling site and its licensed discharge represents che principal source of che water sampled, except after heavy rainfall. The high concentrations of the human faecal scerols and the high scerol ratios of coprostanol/ coproscanol+24echylcopros tanol as shown in Table 3 suggest chat che major contributions of the faecal contamination present were from human sources. For samples B, water samples were collected at a site with in a State Forest catchment where there is no identifiable agricultural or human activity upstream. Accordingly faecal contamination of the water could only potentially come from native animals and the scerol ratios in Table 3 indicate that no faecal contamination from humans and/or herbivores was present.

The enumeration of both faecal and cocal coliform bacteria in water samples is determined by membrane fi ltration following standard methods (APHA, 1998) . Water samples for faecal scerol analysis are filtered using prebaked glass fibre 0. 7 ¾m fil ters. Filters with particulate matter are freeze dried and then kept at -20°C until analysis. Analysis is by GC-MS using 5aCholescane as an internal standard.

Results and Discussion Scerol concentrations obtained at four sites in wee weather periods during 2005 are contained in Table 2. The calculated scerol ratios with both faecal coliform and total coliform numbers are shown in Table 3. An estimate is given of the relative percen cage

Samples C in Tables 2 and 3 were collected at a site within a large catchment where the p rincipal landuse (apart from State Forest on the upper slopes) is herbivore grazing. Although faeca l contamination is present

24-Ethyl coprostanol (ng/L)

48.65

104.06 151.88 6.29 0.00 16.56 22.13 53291.77 5 173 .82

54.73 4.23 0.00 40.99 47.05 15511.75 630.99

according co the bacterial indicators and the coprostanol/cholestanol ratio, che p rincipal source of the faecal contaminatio n is likely co be from herbivore grazing according to the coprostanol/coprostanol+ 24ethylcoprostanol ratio in T able 3. Samples D in T able 2 were collected from a surface drain in an unsewered subdivision. The sample collected o n the 25 February 2005 contained very high coproscanol concentrations as shown in Table 2. This unsewered commu nity is located in a coastal area with typically sandy soils and a shallow groundwater cable. In the area there are 330 unsewered residences at a density of 55-60/km2. App roximately 60 of these residences are drained by the surface drain which was sampled as a pare of this p roject. Apart from a standard septic tank at each residence, effluent is typically dispersed using a small soil absorption system. Given the high water cable, there are many times during the year when the base o f the trench is in contact with the groundwater. This groundwater surfaces in a shallow drain (the sampli ng location) and then enters an estuary contain ing nearby oyster beds. For some time there have been high numbers of faecal coliform bacteria regularly present in surface waters within chis drain. While runoff from a small bushland area within the catchment could contribute co the faecal load of che drain, it seems very clear from the sterol

Table 3. Coliform Bacteria Counts a nd Calculated Sterol Ratios at Selected Water Sampling Sites (sample dates as a bove) . Sample ID

A A B B

C C D

D

Faecal Coliforms !cfu/lOOL)

Total Coliforms !cfu/lOOmL)

Coprostonol/ Cholestanol

3900 880 0 2 480 390 950 110

21000 9000

15.09 10.58 0.11 0.00 1.12

61 64 580 560 19000 4200

0.80 2 1.47 0.47

Epicoprostanol/ Coprostanol

0.02 0.02

Coprostonol/ Cop+24Eth

% Human/Herbivore Contribution

0.97 0.97

100/0 100/0 NA*

0.31

0/100 0/100

NA* 0.00 0.00 0.00 0.03

0.27 0.99 0.79

100/0 100/0

* NA - no faecal contamination from humans and/or herbivores likely to be present.

50 FEBRUARY 2006 water

refereed paper


on-site treatment concentrations (T able 2) and the calcu lated ratios (T able 3) that the p rincipal source o f contamination in these surface waters is the unsewered community. Of concern in this case, where there are large num bers of fai ling on-sire systems, is the public health issue associated wi ch the p otential fo r pathogenic microorganism contamination within the adjacen t aquaculture b eds. Dara collected at a number of the nearby oyster growing sires within rhe estuary by Geary (20 03) and as part of the NSW Shellfish Quality Assurance Program indicate that there are regular exceedances of standards set for shell fis h growing waters (faecal coliforms) an d oyster tissue (E.coli). Recent testing of oyster tissue in this part of the estuary by rhe NSW Food Authority has confirmed rhe presence of several human viruses. As a result, th is part of the estuary has recenrly been closed fo r shellfish harvesti ng (B. Nelan , pers.comm.) and unfortunately fa iling on-site wasrewarer systems from chis subd ivisio n ap pear to be rhe source of the faecal material.

Safe Enhancement Grant Project E08, I 06pp hrrp://www.dlg.nsw.gov.au/D L G/ DLGHome/Documents/lnformation/ E08_Port_Stephens.pdf Geary, P.M. and Davies, C.M. (2003) Bacterial source cracking and shellfis h contamination in a coastal catchment, Wat.Sc. Tech., 47(7/8), 95-100. G ilpin, B.J., Gregor, J. E. and Savill, M . G . (2002) Identification of rhe source of faeca l pollution in contaminated rivers, Wat. Sc. Tech., 46(3):9-15 . Hagedorn, C. (1999) Developing Methods for Bacterial Source Tracking (BST), 10th

Northwest On-site Wastewater Treatment Short Course, Seattle, WA, University of Washingcon and Department o f Health, 6 169.

An unsewered community adjacent to Tilligerry Creek, Port Stephens.

Acknowledgments

The authors are aware char ir is quite possible char rhe scerol profiles of h umans and di fferent herbivo res could vary significanrly between catch ments, and hence the ratio analyses being used could also be differen t. Furn re work is being planned to investigate chis. Along with rhe monitoring results ob tained, it is anticipated chat these various srerol profil es will be p resented in fu ture publications.

T he project is ongoing and the fi nancial support of the following partners is gratefully appreciated: the Australian Research Cou ncil and vario us project partners: Councils - G rear Lakes, Hastings, Pore Stephens and Greater Taree: Water Utilities - M idCoast and H unter Water; Government Departments - NSW Department of Planning, In frastructu re and Natural Resources, Public Works and Services; and Analytical Reference Laboratories.

Conclusions

The Authors

The methodology being used to distinguish sources of faecal contam ination will be refined and developed as the p roject continues and as water samples contin ue to be collected over the next 18 mo n ths. In the exam ples presented in this paper, the use of faecal biomarkers has allowed rhe various so u rces of faeca l contami nation in waters to be differentiated. Of particu lar interest is rhe ap pl ication of this methodology to the con tribution char faili ng on-site wastewater systems may make to the faecal load of a catchment. It is however recommended that ocher indicators such as fluorescent whitening agents or added geochemical tracers be combined wirh rhe ap proach presented in chis paper if there is concern about the possible fare of con taminants from on-sire systems. While potential agricultural sources of bacteria are numerous in any catch ment, rhe contribution char hu man sources may make may also be significant given rhe longevity of human viruses in rhe environment and the potential risks they pose to human health.

All authors are from the School of Environ mental and Life Sciences at T h e U niversity of Newcasrle, Callaghan, NSW. Dr Phillip Geary (email Ph il.Geary@ newcasrle.edu.au) is a Senior Lecrnrer; Vikas Shah is a Post-graduate Research Student, Dr Hugh Dunstan is an Associate Professor, Dr Peter Coombes is a conjoint Sen ior Resea rch Fellow and Tony Rothkirch is Laboratory Manager.

refereed paper.

References APHA (1998), Standard Methods for the Examination of Water and Wastewater. 20th edition. APHA, Washingcon DC. Pp. 54-65. Beal, C., Gardner, T., Christiansen, C. and Beavers, P. (2003) Audit of Non-Sewered Areas in South East Queensland, Task I Report, Department of Natural Resources and Mines, Brisbane. Brown and Root Services (200 I) O n-site Sewage Risk Assessment System. Report prepared fo r NSW Department of Local Government, Bankscown NSW by Brown and Root Services. Geary, P.M. (2003) On-site T reatment System Failure and Shellfish Contamination in Port Stephens, NSW, Report prepared for NSW Department of Local Government, Septic

Leeming, R., Nichols, P.D. and Ashbolt, N.J. ( 1998) Distinguish ing Sources of Faecal Pollution in Australian Inland and Coastal Waters usi ng Sterol Biomarkers and Microbial Faecal Indicators, Research Report No. 204, Urban Water Research Association of Australia, Melbou rne, Yiccoria, 46p. Roser, D .J. , Ashbolt, N .J. , Leem ing, R., Kagi , R. and Waite, T. D. (2003) Source Water Fingerprinting using Sterols and Particle Size Analyses and the Management o f Faecal Pollution and T urbidiry, Proceedings of28th

International Hydrology and Water Resources Symposium (eds Boyd, M.J ., Ball, J.E., Babister, M.K. and Green, J.) , Wollongong NSW, The Insti tution of Engi n eers, Aust ralia, Volume 2, 355-362. Sargeanr, D. ( 1999) Fecal Contaminat ion Source Identification Methods in Surface Water, Washington Seate Department of Ecology Report #99-345, Olympia, WA. Scott, T. M ., Rose, J. B., Jenkins, T. M., Farrah, S . R. and Lukasik, J . (2002) M icrobial source tracking: current methodology and future directions. Applied a11d Environmental Microbiology. 68( 12):5796-5803 . Shah, V.G., Dunstan, H . and Geary, P.M. (2004) Application of Emerging Bacterial Source Tracking (BST) Methods to Detect and Dist inguish Sources of Fecal Pollution in Waters, In Proceed ings of I nternat ional Conference on E merging Tech nologies (ICET-2004), Eds D.K. Mishra and P.N. Ramachandranan, December 22-24, Bhubaneswar, India, 11 7- 126. Sinton, L.W., Finlay, R.K. and Hannah, D.J. (1998) D istinguishing human from animal faecal contamination in water: A review. N.Z.j. Marine and Fmhwat. Res. 32, 323348. Suprihatin, I., Fallowfield, H., Bentham, R. and Cromar, N. (2003) Determination of faecal pollutants in Torrens and Patawalonga catchmenr waters in South Australia using faecal sterols, Wat. Sc. Tech., 47(7/8):283289. Wiggins, B.A. (1996) Discriminant analysis of anribiotic resistance patterns in fecal streptococci, a method to differentiate h uman and animal sources of fecal pollution in natural waters, App. and Env. Microbiol., 62, I I , 3997-4002.

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on-site treatment

PERFORMANCE AND AUDITING OF MEDIUM SCALE ON-SITE WASTEWATER SYSTEMS 8 Asquith, L Shelly, J Whitehead Abstract This paper d iscusses medium scale wastewater systems (1 0-2500 EP) in terms of rhe range of fac ilities serviced, the types of treatment and land application systems, the characteristics of rhe wastewater, and common problems with their design and operation. A case study of a highway service centre is used co illustrate these and promote a methodology for auditing and improving performance.

Introduction T he need ro better manage single household on-sire wastewater management systems has led some Australian regulatoty authorities and independent third parry assessors to develop more systematic approaches to documenting system performance. Less attention has been paid to developing rigorous and systematic reviews of med ium (larger than single ho usehold) and institutional scale on-site systems to assess their risk to public health and the environment. Medium scale systems are characterised by a wide range of designs and tech nologies. Such systems are commonly individually designed and built and iris quire rare to find two char are alike in all respects. Some planes are designed and constructed by individ uals with limited experience, a number by short lived players in the marketplace, whilst others are designed, manufactured and installed by a relatively small number of well established and experienced companies. These medium scale plants are often poorly understood by chose who own, service, and regulate chem, resulting in many examples of poor performance. Because of rhe size of the planes, chis can result in significant risks to environmental and pu blic health .

Where do these Systems Occur? For the purposes of chis paper, medium scale on-sire wastewater systems are defined T his paper is an abbreviated version of the refereed paper presented at the On-site 05 Conference, Armidale, September 2005.For full derails see the acknowledgement on page 36.

52 FEBRUARY 2006

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as chose servicing a population between 10 and 2500 equivalent persons (EP) at a single facil ity. They are found at caravan parks, campsites, resorts, highway service centres, schools and co mmunity facilities. Examples of such fac ilit ies are presented in Table 1 along with typical load and flow characteristics. They display a range of performance, operational, maintenance and management challenges. Many systems and land application areas are undersized d ue to growth of the facilities serviced and, due to their age, do nor meet current design and performance expectations. A comprehensive understanding of treatment processes and sire specific factors, not always encountered in single household assessments, is required to prevent adverse environmental and pu blic health impacts.

Medium scale plants are often poorly understood by those who own, service, and regulate them. Local Councils and stare government regulatory agencies often have limited expertise in dealing with these medium scale systems and their particular problems yet in NSW rhe regulation of such systems has been transferred to. Councils from rhe Department of Environment and Conservation with the introduction of rhe

Protection ofthe Environment Operations Act (1997). Private contractors, who often have responsibility fo r inspecting and servicing these systems, commonly come from either single household domestic or municipal wastewater treatment plant backgrounds and similarly may have limited expertise. This paper fills the gap between these two extremes of scale and promotes rhe development of a systematic consideration of all system components from the characteristics of wastewater inputs through to the sustainable re-use of created effluent to achieve positive performance outcomes.

The Regulatory Framework The agency responsible fo r regulation of medium scale systems varies from scare to scare. In some scares, rhe Environment Protection Authority regulates chem. In NSW, the Department of Environment and Conservation (DEC) directly regulates systems with capacity of over 2500 EP or 750 kilo litres per day, bur Councils generally have responsibility to approve all sewage management systems larger than 10 EP(rhe upper limit of single household domestic systems) and up to 2500 EP. I n NSW, in lieu of other guidance, local government may use rhe Environment and

Health Protection Guidelines: On-site Sewage Management for Single Households (DLG, 1998). However, whilst many of the basic principles provided in terms of sire and soil assessment and hydraulic and nutrient loading may be applicable, nor all rrearmenr process or land application options fou nd in med ium scale systems are covered in chis guideli ne, nor is there any information on rhe significant additional factors char must be considered in the design and operation of these systems, such as temporal and qualitative variations in loads. One of rhe major difficulties facing Councils in the regulation of these plants is the lack of standards or guideli nes chat apply to them specifically, with rhe exception of Effluent Reuse by Irrigation (DEC, 2004), which only deals with land applicat ion and rhe lack of guidance available in what is a specialised area. O ne of the reasons for this is the enormous variation that occurs in the systems, particularly in rhe combination of treatment and land application options. This presents a challenge to state government regulators, with whom provision of these documents falls, to adequately provide tech nical information and advice char will be useful to regulators, designers, and operators.

The Types of Systems Encountered Package Treatment Plants â&#x20AC;˘ Activated Sludge Planes: traditional secondary treatment plants with mechanical aeration.


on-site treatment Table l. Typical Flow C ha racteristics of Medium Scale Wastewater Systems. Type of Facility

Typical Daily Load (Litres)!

Flow Characteristics

Pollutant Load Characteristics

Tourist Park (permanent on-site vans/cabins or mobile tents and vans)

10,000 - 30,000

Highly variable - hol iday peaks

As for domestic.

Highway Service Centre (typically include service stations, fast food restaurants, truck stops and public toilets)

40,000 - 150,000

Variable according to time of day, and whether holiday period or weekend

High trade waste load , blackwater predominantly liquid. May also include stormwater with hydrocarbons.

School · primary School · high

10,000 40,000

Concentrated during school hours and terms

Predominantly blackwater.

Community Facility (halls, function centres and public toilets)

200. 4,000

Intermittent - can have high peak loads followed by long periods of no flow

Predominantly liquid load, except when kitchen wastes included.

Wi nery (usually multi-purpose facilities such as restaurants, accommodation and wi nemaking)

1,000 - 100,000

Highly variable across the year, with Usually includes a number of peaks in vintage season and with different wastewater streams. tourist visitation Typically has high BOD, pH from 3-10, and moderate salinity. Can also have fats and greases if a restaurant is included.

Industrial (mines, light industrial facilities)

1,000 · 20,000

Can be intermittent and highly variable

Sometimes simply wastewater from worker facilities. Other cases may include trade woste inputs.

Hospitals, homes and retirement villages

10,000 · 50,000

Relatively constant

Loads are problematical for system performance due to the high use of biocides for cleaning purposes and drug administration, especially antibiotics.

1. Based an numerous audits of medium scale facilities undertaken by the authors. • Sequencing Batch Reactors and Intermittently Decanted Extended Aeration Plants: these batch type systems are common due co their typically smaller size. • Extended Aeration Attached Growth Planes: such as slightly enlarged Aerated Wastewater T reacment Systems (AWTS) incorporating fixed media. • Rotating Biological Contaccors (RBCs}: using rotating discs or drums of media fo r biofilm development and aeration through exposure co the atmosphere. • Trickling Filters: including traditional rock media filters and high race recirculating units with plastic or fa bric media.

Wetlands, Ponds and lagoons • Constructed Wetlands: including free water surface wetlands and reed beds are sometimes used, particularly where there is a need co manage a combination of wastewater and scormwater.

breakdown of highly concentrated organic loads such as abattoir wastewater. • Maturation Ponds: usually shallow, long ponds designed fo r pathogen reduction.

Other Treahnent Systems • Packed Bed Filters: such as sand and peat filters, some with nutrient sorptive capacity, are becoming more prevalent. • Primary Treatment: septic or primary settling tanks. In some cases this may be the only form of wastewater treatment.

land Application/Reuse Options • End of pipe discharge (land or waterway}: still common based on previously issued (ofren defunct) discharge licences. • Surface irrigation: the most common land application option in existing systems. Sometimes effiuent is used for the active irrigation of a crop or recreation area, sometimes irrigation is used purely as a means of disposal.

• Facultative Lagoons: these rely on residence time and interaction between algae, aerobic microorganisms and anaerobic microorganisms for wastewater treatment (USEPA, 2002).

• Subsurface irrigation: becoming more popular particularly in areas with public access.

• Aerated Ponds: utilising mechanical aeration of wastewater in either a partial mix or fu ll mix configuration. • Anaerobic Lagoons: sometimes used as one part of a treatment chain for the

Common Problems

• In rernal reuse.

T he wide variation in the types and combinations of medium scale wastewater systems ensures chat problems encountered are equally variable. Based on our

experience of auditing, rectifying and monitoring different medium scale systems, there are three key problems commonly observed. These are; a lack of consideratio n of hydraulic and pollutant load characteristics, a lack of commitment co and/or a poor understanding of system operation and maintenance, and poorly sized system components. Eight systems recently audited, rectified and monitored by rhe authors included six different treatment technologies and four land application methods. Hydraulic loads varied from 2,000 co 146,000 litres per day and influent pollutant concentrations varied over wide ranges: biochemical oxygen demand (5-day} 150-550mg/L; coral suspended solids 50-345mg/L; total ni trogen 50-220mg/L, and coral phosphorus 8-40mg/L, quire apart from the significant trade waste and chemical inputs produced by most facilities of chis scale. A summary, but not exhaustive, list of the most common problems is provided in Table 2.

Case Study: Highway Service Centre In September 2004 rhe authors were engaged to carry our an audit of a medium scale wastewater management system on the mid north coast ofNSW. The system was installed in 1994 as a high rare recirculating trickling filter with ozone disinfection char

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on-site treatment Table 2. Common Problems Encountered wi th Medium Scale Wastewater Systems. Process

Problem

Potential Impacts

Design

Poor understandi ng of hydraulic and pollutant load characteristics (partic ularly temporal variation).

• Poor efflu ent quality. • Operational problems with treatment plant. • System overflow.

Undersized land application areas, inappropriate buffer distances and poor equipment selection.

• Soil satu ration, effluent ponding, weed proliferation. • Human exposure to poorly treated effluent. • Pollutant export· environmental and public health impacts.

Oversized land application areas.

• Poor vegetation condition a nd growth. • Can create the need for additional water and nutrients to be imported when the land application area is a managed reuse site (such as pasture or fodder crop).

No consideration of trade waste a nd starmwater inputs.

• Shock hydraulic and pollutant loads disrupting treatment processes. • Occupational health and safety risks. • Damage to components (e.g. corrosion) .

Inappropriate combi nations of treatment and land application processes.

• • • •

Selection of unsuitable system components (e.g. control equ ipment).

• O ngoing breakdown of components (increased operation and pumps, filter media, mai ntenance costs). • System blockage, failure, overflow and runoff. • Public health and environmental impacts.

Poor project management or failure of installation firm to conform to system design .

• System does not perform as designed and approved by the regulatory authority. • Stormwater ingress. • Pond leakage.

Lack of financial and resource commitment to managing the system. Poor understanding of how the system works and the correct O&M procedures.

• • • • • • • • •

Replacement of original components (e.g. pumps) w ith less suitable/ durable ones.

• Operational problems with treatment plant. • System breakdown and failure. • Ineffective treatment processes.

Excessive inputs of biocides (disi nfectants, antibiotics) and trade waste.

• Significant disturbance to biological treatment processes. • Damage to components (e.g. by high / low pH or high fats and oils) . • O H&S risks.

Inadequate control of access to system components.

• Vandalism of components. • Accidental system damage . • Injury to, or illness of a member of the public .

Significant change in hydraulic and pollutant loads due to land use change.

• Poor system performance as design may no longer be applicable. • Public health and environmental impacts.

Insufficient monitoring of system undertaken.

• Incorrect problem and solution identification. • Detrimental changes to system operation. • Inability to demonstrate fulfi lment of duty of care.

Installation

Operation and Maintenance (O&M)

pumped to storage ponds fo r land application. T he system was in a state of disrepair with most mechanical components not operating, resulting in wastewater simply flowing by gravity out of the top of the final holding well. W hen the lift pump to the ponds was operating, land application of 'effluent' was thro ugh end of pipe discharge into a moderately sloping dry forest that drained to a local shallow coastal lake. As a consequence the local Council issued an on the spot fine for a pollution incident in addition to a prevention notice requiring the system to be audited, rectifi ed and

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water

Overloaded treatment components. Ineffective treatment processes. System breakdown and failure. Public health and environmental impacts.

O&M d uties neg lected (sometimes permanently) . Inappropriate modification of the system . Long-term degrada tion of system condition. Consistently poor effluent quality and failure of the land application area. Complete breakdown of the system to a condition of a lmost no treatment. Significant sludge build-up and downstream impacts. Occupational Health and Safety (OH&S) risks. Public health and environmental impacts . Amenity impacts (odour, visual, weed growth).

operated in an appropriate manner. The system had received little o r no maintenance since it was installed in 1994 and there was a lot of work to be done!

Auditing Performance: What are we Managing? Before any assessment can be made of the capability of a wastewater system to perform effectively, it is essent ial to determine the nature of the wastewater load by quantifying the variation in hydraulic and pollutant loads over a number of timeframes. Simply adopting peak daily load as a design loading rate (as would be

the case with do mestic systems) is not appropriate. The option chosen to estimate hydraulic load will depend on available budget and consideration of what resolution of data will provide sufficient detail for that particular system. If possible, info rmation chat can be used to estimate historical wastewater loads should be sought. A proportion (typically 6 0-80%) of potable water use (where available) can be used to estimate wastewater loads. However, this information can usually only generate monthly averages at best, masking significant variation from day to day. Some circumstances allow the use of 'hours run'


on-site treatment meters and estimated pump fl ow rare to calcu late hydraulic load. However, significant variations in fl ow rare can have an effect on rhe accuracy of data. T he most accurate way to measure hydraul ic load is to install a flow merer ar rhe inlet to rhe system and instigate a daily mo nitoring schedule. T he additional rime and cost associated with obtaining accurate flow data will be far less rhan rhe potential costs (in maintenance, repairs or upgrades) if a system is grossly under or over sized.

been applied to the primary t reatment tanks. The need for sludge storage in each of rhe primary tanks had also not been considered. The whole treatment system was not designed to balance peak flows, with raw wastewater loaded using a float switch. Secondary treatment processes require a steady input of wastewater to work effectively. Given che variable nature of hydraulic and poll utant loads, flow balanci ng should be considered essential fo r such a site.

T he use of generic guidelines for estimating poll utant concentrations should be approached with caution. Furth ermore, raking a single sample of influent and having it analysed fo r pollu tants of co ncern will nor necessarily provide an accurate depiction of pollu tan t loads. T he biochemical characteristics of wastewater vary significantly over rime (Patterson, 2003). Ir is important to recogn ise rhe limitations o f whatever data is obtained before making any management o r des ign decisions. Assessing rhis data in co njunction with fl ow data, cl imate in fo rmation and sire activities is essential to accurate d iagnosis.

The large raw wastewater collectio n well provided substantial capacity for flow balancing by installing a rimer control sec to dose small , frequen t loads co the first septic tank. Further fl ow balancing was mad e possible d ue to the presence of a dosi ng rank between primary and secondary treatment. By carrying o ut a cumu lative storage assessment, ir was determined that these two tanks would enable balancing of flows up to fo ur times the average load. Various loading scenarios were reseed (e.g. Christmas, Easter, long weeken d) to ensu re peak loads cou ld be managed.

Th e only data avai lab le for assessmen t of hydraulic loads from the h ighway service centre were hours-run data fo r two pumps that conveyed raw wastewater from a collection well to rhe fi rst septic rank. However, ch is data had been recorded daily over holiday periods and otherwise o nce or twice a week for twelve months giving a reasonable dataset. T he results of previous composite sam pling were used to estimate pollutant loads. I n add ition to significant variation in hydrau lic and poll utant loads, substantial storm warer inputs were identified .

Auditing Performance: Treatment Process Assessment The estimated hydrau lic and po ll utant inputs (and their variation over the previous twelve months) were used initially to assess the treatment capacity of the existing process design. A fu ll audit of the system was carried out using an established audit protocol, developed specifi cally for regulators, system designers and operators, to con fi rm the specifications of the various treatment components and identify contributions to poor performance. The expected performance was assessed against a nu mber of recognised standards available for package treatment plants. Some key references include Bounds (1994), Crites and Tchobanoglous (1998), Tchobanoglous et al. (2003) and various USEPA design manuals. There are very few Australian publications that provide design criteria for medium scale treatment systems.

Figure 1. Highway Service Centre prior to audit a nd rectificatio n: Tan k 1 show ing impact of shock loads overtopping filters. Ir was fo und rhac wh ile the poll utant removal capabilities of the system had been accurately calculated d uring the design, rhe average influent Biochemical Oxygen Demand (BODS) was significa n tly underestimated (estimated - 430mg/L, actual - 554mg/L). Fu rthermore, wh ile the trickling filte r had been designed to be capable of accepting and creati ng peak hourly flows, rhe same scrutiny had nor

Figures 1 and 2 demonstrate the improvement after three months rectification.

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FEBRUARY 2006

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on-site treatment considerations in the assessm ent and rectification of a typical medium scale system. To enable regulators, operators, designers and technology providers to begin to work towards a consistent management framework to improve the performance of these plants clear guidance in the form of design guidelines, new system approval guidelines, operation and maintenance plans and audit protocols, for both new designs and existing systems, could be usefully employed.

A number of other problems were identified beyond the design process. Domestic scale pumps and controls were installed that were not capable of performing the duty expected of them. The dosing manifold for the trickling filter consisted of 100mm PVC pipe with an open end, meaning distribution of effluent was fa r fro m even! A rectification program was developed and used to calculate a predicted effluent quality to be discharged to the storage ponds for irrigation.

.

Auditing Performance: Land Application/Reuse System Assessment The evaluation of the performance of land application or reuse systems should focus on two areas. Firstly, ensuring chat reuse is carried out in a sustainable manner that does not pose an unacceptable risk to public health and the environment; secondly, ensuring that the effluent is reused in an effective and efficient manner based on the selected option. There is significant informatio n on the first consideration including the current state guidelines Effiuent Reuse by Irrigation (DEC, 2004). In many cases existing medium scale systems do not have a suitably sized land application area. It is important to carry out a site and soil assessment to determine a minimum land application area size. There is no point in providing a high level of treatment at the plant if effluent is allowed to runoff or overload and degrade the area. Wee weather management becomes more important at this scale and is commonly achieved through the use of ponds and rain sensors or soil probes. If effluent is reused for a specific purpose, it is important to consider suitable effluent quality and quantity. The irrigation of certain crops or reuse infrastructure may require specific parameters to be given closer scrutiny than would be the case if final use is essentially disposal (NWQMS, 2000). This is particularly important when a system receives trade wastes that may contain heavy metals, very high nutrient concentrations, hydrocarbons, high salinity or fats and oils. Irrigatio n scheduling must meet the requirements of the reuse scheme in addition to managing risk to public health and the environment. Pond effluent from the highway service centre was irrigated to a section of land chat was considered to have moderate limitations to effluent application. H owever, the area was half the size needed to satisfy a monthly water balance. At the time of inspection, the soil in this application area showed significant signs of long-term saturation and high nutrient loads. An additional area was identified that was well suited to effluent

56 FEBRUARY 2006

water

.

;

. !-1

.... . .

·. . . ''

'~ ·.

..' :, .•. -~ . l

...

.•, ...;: . ~~ ..f.;::-~' ~ ', \

~ '

Figure 2. Three months later fol lowing audit and rectification. Tank l - outlet filter performing wel l with microbial activity matched to balanced flow. irrigation and irrigation infrastructure was put in place. A sustainable and adaptable irrigation schedule was developed based on water and nutrient balances and effluent loads coming from the treatment plant. A suitable wet weather management system was also implemented.

Operation and Maintenance Regular monitoring and mai ntenance of all system components is crucial to the effective performance of medium scale systems. There is coo much variability in hydraulic and pollutant loads co simply leave things to look after themselves. Despite this, a lack of monitoring and maintenance is a common cause of system failure. A user friendly Operation and Maintenance (O&M) manual was developed for this service centre that covered weekly, quarterly and yearly monitoring and maintenance casks and provided troubleshooting advice to the operators. The rectification works have now been completed and the system is being managed effectively with improved effluent quality, chat meets regulatory criteria, and a sustainable and managed irrigation system.

Conclusions Based on our experience in the design, installation, assessment, rectification and management of medium scale onsice systems, there is a clear need for a systematic and rigorous framewo rk for performance assessment. This paper provides some guiding information on the nature of med ium scale facil ity wastewater, the types of systems encountered and common problems associated with their design, installation, operation and management. The case study illustrates some of the key

The Authors Ben Asquith is a Consultant specialising in small and medium scale wastewater treatment systems with W hitehead & Associates Environmental Consultants, Taree, NSW. Email benasquith@ whiteheadenvironmental.com.au; Liz Shelly is involved with the preparation and presentation professio nal short course training in medium scale wastewater systems at the Centre for Environmental Training, Newcastle, NSW. Email lizshelly@environmentalt raining.com.au; and Joe Whitehead (the corresponding author) is a Sen ior Lecturer with research and teaching interests in wastewater treatment at the University of N ewcastle, C allaghan, NSW. Email joe.whitehead@newcastle.edu.au

References Bounds T.R. (1994). Septic Tank Sizes for Large Flows in Proceedings of the Conference of the American Society of Agriculcural Engineers, Atlanta Georgia. Crites, R.W. & Tchobanoglous, G, (1998).

Small and Decentralised Wastewater Systems, WCB, McGraw-Hill, New York. NSW DEC (2005). Environmental Guidelines: Use ofEffluent by ln·igation. NSW Department of Environment and Conservation. Sydney, NSW. N SW Department of Local Government ( 1998)

Environment and Health Protection Guidelines: On-site Sewage Management for Single Households. DLG , Sydney, NSW. NWQMS (2000). Guidelines for Sewerage Systems: Use ofReclaimed Water. Published as National Water Quality Management Strategy. No. 14 ARMCANZ/ANZECC/NHMRC. Canberra, ACT. Patterson, R.A., (2003). Temporal Variability of Septic Tank Effluent in Proceedings of Onsite '03 Conference: Future Directions for On-site Systems: Best Management Practice by R.A. Patterson & M.J. Jones (Eds). Published by Lanfax Laboratories, A rmidale. pp 305-312. Tchobanoglous, G., Burton, F.L. & Stensel, H.D. (2003). Wastewater EngineeringTreatment and Reuse, 4 th Ed., Metcalf & Eddy Inc., McGraw Hill, New York. USEPA (2002). Onsite Wastewater Treatment Systems Manual. United States Enviconmental Protection Agency, Washington.


WATER AND ENERGY REQUIREMENTS AT A TENANTED RESEARCH HOUSE B Kele, K Hoffman, N Orr, P Wolfs, I Tomlinson, D J Midmore Abstract

legislation (Residential Tenancy Authority Act) restricts the access

Research H ouse, buil t in rhe sub-tropical city of Rockhampcon, is part of the Q ueensland Department of Housing's 'Towards H ealrhy and Sustainable Housing Research Project'. The aim of the ven cure was co construct a ho use with passive sustainable building design and co mon icor how rhe featu res worked with a ren tal cl ienrele, who would have min imal interest in the outcomes, in contrast co ocher 'sustainable houses' occupied by environmentally concerned owners. Both water and energy usage have been collected and collated for two groups of tenants.

that landlords, or people acting on their behalf, have co a rental property.

Research House is an extremely valuable tool as it provides information on how members of the general pub lic can live in a sustainable man ner. Many sustainable housin g research projects rake place i n private dwellings using ho u seholders who are already commi tted co a resou rce-efficient lifestyle (Gardner and Millar, 2003). While these studies are valuable they may overestimate the potential resource savings of a housi ng design due to the user patterns and beh avio u r o f rhe householders. As rh e tenants Keywords: Energy usage, change over rime in Research housing d esign, sustainability, House, d iffe rent user patterns Figure 1. Artist's impression of Research House floor plan. user patterns, water and behaviours will be able co co nsump tio n be assessed. T he in frastructure at Research House wi ll also be Introduction able co be assessed o n how irs efficiency Research H ouse is part of the 'Towards performance degrades overtime. Stud ies at H ealthy and Sustainable H ousing Research resorrs/horels have shown ch ar d rips and Project', an initiative of the Q ueensland leaks maintenance p rograms are requi red o n Stare Government. T he Q ueensland some infrastructure for ir co m aintain its Dep artment of H ousing has a 'Smarr responsive to naw ral breezes, has in novative efficiency (Kele et al., 2003) . Housing Program' that ai ms to develop ap proaches co insulation and ventilation, T h is paper describes rhe water efficient housing designs that have social, and uses energy and water efficient in frastructure installed ar Research House, environmental, and econom ic sustainability in frastruct ure (see Figure 1) (QG, 2005). the water consumption of each individual (QG, 200 5). A 'Smarr H o use' is safe, As par t of the social sustainability p rogram component and its energy requ i rements. livable, resource efficient, and cost-efficient the mechanisms which Research House uses over-time. Research House is intended co to conserve resources are passive in nawre Infrastructure and Data Collection trial one of rhe 'Smarr House' d esigns (QG, (QG, 2005). Research H ouse is a rental There were two design p hilosop h ies used co 2004). property and part of the Q ueensland ensure char rhe basic criterion of economic Research H ouse has b een constructed in the Department of H ousing public housing sustainability was mer for rhe water su b-trop ical city of Rockhampcon, using stock. T he tenants who live in Research in frastructure; water efficiency and volume environmentally friend ly materials (such as House have been taken from the normal fill (QG, 2004). Ir was understood char fly ash b locks), has been d esigned co be p u blic housing waiting list and are not while most items in the house could be selected on the basis of environmental built using water-efficient infrastructure, awareness. Since Research House was built some items, such as rhe bath, were fi lled by T his paper is an abbreviated and updated there have been several changes in tenancy people co a des ired depth regardless of the version of the refereed paper presented at che (QG, 20 04). The technology used at rap-flow rare. So the cost of installing flow On-site '05 Conference, Armidale, September 2005. For full details see the acknowledgement Research House must be robust and have resrriccors on rhe bath raps was never going on page 36. co be recouped. Economics is quire often limited main tenance requirements as

Data on a 'sustainable' public housing project.

refereed paper

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FEBRUARY 2006 57


on-site treatment thought of in the broad scale but ignored fo r smaller items (Beatty et al., 2005); (Choe and Fraser, 1998). The entire water and energy efficient household infrastructure was purchased with the intention that any excess mo ney spent on a more expensive item (such as hot water system) or a new stand-alone item (such as a flow restrictor) would be recorded and a pay-back period in years would be calculated using the money saved from reduced water bills (QG, 2004) . This type of calculation is required to provide an economically sustainable determination of the house design (lcke et al., 1999). All wastewater-generating infrastructure was equipped with a water meter (see Table 1) . If the item used electricity an energy sensor was installed. The water and energy efficiency of each appliance was theoretically determi ned. At Research House a 75-channel data logger was established to collect water, energy, temperature, and weather sensor information. The data from the fiftee n water-flow sensors and four relevant energy sensors will be discussed in this paper. Water volume was measured using water turbine transducers (QG, 2004). As water flowed through the transducers, turbine blades rotated interrupting a laser light from a digital optical transmitter, which in turn creates a d igi ral pulse that is recorded and converted into a water volume (QG, 2004) . This for m of data collectio n allows for precise knowledge on a min ute-tominute basis as to what volume of water was used in specific locations within Research House. Problems with suspended solids in the reticulated water supply were encountered in the earlier months of the trial. An in-line filter to remove the solids was installed directly after the water-mains en try to the property and the problem was solved (QG, 2004). The major electrical components were individually metered; smaller appliances could not be metered bur a formula for electrical requirements was calculated (QG 2005). All the logged data were compiled and presen ted through LabVIEWâ&#x201E;˘.

Results and Discussion The water use figu res from two different tenancies are presented in this report. Information from Tenants A was collected from the 1st of December 2002 to the 30th of November 2003. There were two adults and three teenage children, one of the teenage children was only present for part of the year (QG 2004). T enants B moved into Research House on the 1st of January 2005. Eight months worth of Tenants B data are presented in this report. T he data

58 FEBRUARY 2006 water

Table 1. Wastewater Generating Infrastructure, Data Collection, and Efficiency Rating. Item

Water Sensor (Y/ N)

Water Efficiency Rating

Energy Sensor (Y / N)

Energy Efficiency Rating

Hot Water Unit Ensuite Toilet Ensuite Shower Ensuite Vanity Toilet Toilet Vanity Bath Kitchen Sink Dishwasher ZIP hat/cold Tap Bathroom Van ity Bathroom Shower Washing Machine Laundry Tub Mains

y

Unrestricted Volume fill 3/6 Ldual flush 9 L/mi n 6 L/min 3/6 Ldual flush Automatic Sensor Tap Unrestricted Volume fill 9-12 L/mi n M A 8 L/min Unrestricted Volume fill 6 L/min 9 L/m in AAA 8 L/min Unrestricted Volume fill Unrestricted

y

5 stars N/A N/A N/A N/A N/A N/A N/A 4 stars Unava ilable N/A N/A 4 stars N/A N/A

y y y y y y y y y y y y y y

collection computer suffered a malfunction that resulted in the loss of 7 weeks worth of records. Two adults and three teenage children moved into the house and were joined by another person at rhe end of September 20 05. Dara comparison with other reports for water and energy consumption is d ifficult as most articles derail info rmation o n a per household basis rather than a per capita. T he number of people living inside a household can be a major facto r when considering water and energy usage. While rhe data are reported as a household figure, a per capita figure can be obtained for the presented data by dividing by 4.67 for Tenants A and by 5. 16 for Tenants B. The energy meters attached to the dishwasher and washing mach ine showed that actual electrical requirements were significantly different to the manufacturer's predicted energy label usage for the period between December 2002 and November 2003 (see Table 2). The d ishwasher (Dishlex - Electrolux Australia) used ap proximately 17% more electricity than envisaged and the washing machine (Front-loader Westinghouse Electrolux Australia) 10% less. T here has been much debate in the water industry about sustainable housing design and washing machines in particular, such as

N N N N N N N y y

N N y

N N

top-loader versus front-loader machines (see http:/ /www.nrm.qld.gov.au/ lisr_archives/ water-recycling/ index.h tml). Much of the information for this debate has been obtained from the manufacture r's energy label rather than from mach ines in households and fi eld-tested data. T he manufacturer's information is based o n a projected daily figure achieved u nder ideal min imum energy performance standard s conducted under a controlled laboratory environment (QP 200 5). H ouseho lders can use resou rce-efficient infrastructure q ui te ineffi cien tly, and vice-versa. T he dishwasher may have used more electricity because it was overloaded or the householders may have been using specific high-energy washcycles. T he information shows that in relation to energy it may be more sustainable to have smaller more frequent washes. The debate between fro n t-load ing and rep-loading washing machines is largely meaningless if user patterns and behaviou rs are not considered. Educating householders on p roper usage is still important even in a passive designed house with resourceefficient infrastructure. In Table 3 the yearly energy usage for Tenants A on selected items at Research House are p resented. The house did not have any air-conditio ners (ceiling fans are present) or heating mechanisms. The nonwastewater generating energy use within the

Table 2. Predicted Energy and Actual Energy Use for Selected W hitegoods for Tenants A. Item

Dishwasher Washing Machine

Energy Label kWh/yr

Actual Energy Use kWh/yr

256 225

307

205

refereed paper


on-site treatment house was lights, fans and entertainment devices (36%), freezer, clothes dryer, and microwave (14%), refrigerator (14%) and electric oven (1 0%) (QG 2005). For Tenant B rhe energy used by rhe washing machine, dishwasher, and zip hot/cold water rap was available, bu r at rhe rime of this publication the relative percentages could not be calculated.

outdoor use for both Tenants is assumed to be for garden i rrigation it for Tenants A. also includes car washing and other ou tdoor water activities. The garden Item Percentage of Energy Use at Research H ouse was designed to Wash ing Machine 2.3% have minimal water requirements Dishwasher 3.4% (drought-proof plants) and a water Zip Hot/Cold Top 6.8% efficient irrigation mechanism Hot Water System 13.5% (automated irrigation sys t em) (QG 2004). However, ir was observed rhac rhe tenants did water the garden The hot water system used at to a standard off-peak system. The long themselves through sp rinklers, garden hoses Research H ouse for rhe fi rst year of the trial payback period isn't of great concern as the and soakage hoses. The householders also utilised a heat pu mp technology system has a tank-life warranty of fifte en applied addi tional irrigation water to the {Quantum), where hear is d rawn out of one years; which is considerably longer than yard from the two rainwater tanks. It was space and discharged into another {QG most off-peak electric technologies. The not possible to quantify the amount of 2004). The Quantum hot water system Q uantum system does produce a noise from irrigation water supplied from the rainwater does not have a hearing coil at the base like the compressor, wh ich is about 52 dBa ar a tanks (QG 2004). The volume of water most other systems, but instead has a distance of 1.5 m or approximately that of a used for outdoor activities highl ights the heating coil that runs the fu ll length of new standard domestic refrigerator. From importance of householder education in structure. This equates to an even water rhe data collected the heat pu mp system regards to user patterns and behaviours. temperature throughout the system and less appeared to be a more susrainable optio n Drought resistance plants should nor have water wastage from people letting water run than conven tional boilers fo r the hearing of required chis amou nt of water so it is through a tap until it is warm {QG 2004). domestic water. possible that the planes were over-watered Over rime the hot water technology at Table 4 describes the water usage figu res for As many people consider watering che Research H ouse will be changed so that Tenants A and B and compares rhe data garden co be therapeutic how does this different systems can be tested. The with the Australian averages. T he water practice fit into the concept of resou rce Quantum tech nology will be replaced by an usage for the hot water system could not be efficient housing design? electric boosted solar hot water system separately described in Table 4 as the hot {Solahart), which in rum will be subst ituted Inside Research House rhe largest water water was used in a variety of items. Ir is with an instantaneous gas system (Bosch). consumption was from showers a nd baths known char the hor-warer system used 129 (approximately 211 L/day) fo r Tenants A, The Quantum system used app roxi mately L of water/day ( 11% of total use) over che 60% less energy than is reported for an and che toiler for Tenants B (approximately T enant A period (QG 2004) and 242 L of 214 L/day). The differences in indoor average Queensland off-peak electric hot water/day (10% of total use) during Tenant water system (QG 2005) . This equates to a percentage of use between Ten ams A and B

Table 3. Water Related Infrastructure Energy Use

B.

saving of about 777 kg per annum of green house gases (G HG). The energy efficiency of a Quantum hot water system can be exp ressed as a coeffi cient of performance (COP), The Quantum system at Research House had a mean COP of 3.09 which means that for each u nit of electricity sup plied from the mains another 3.09 was sup plied free from rhe environment. Depending on the volume of water heated the Quantum system would take between 5-7 years before the added cost of its insrallarion would be paid back in relation

l t is important to note that the data for T enants A and Bare collected over two d ifferent rimes, so rhe percentages give a better indication of user patterns than rhe raw water-use figu res. It can clearly be seen that the majority of the reticulated water at Research House was used for outdoor purposes. Tenants A and B both used higher percentages of water outdoors than the Australian average; with Tenants B using nearly three-quarters of their total water ou tside. While rhe majority of

clearly shows char user patterns can have a big difference as to where and when water is used and wastewater is produced. The Aow-mecers recorded an average shower rime of less than 5 minutes fo r Tenants B, while for T enants A ir was closer to I 0 minutes. Tenants B used the bath less than twice a month and T enants A on a weekly basis. The amount of water used by T enancs A in the showers and bath closely corresponds with the Australian average. This is not che case with T enants B but it muse be considered chat their high outside

Table 4. Water Use Figures for Tenants A ( 12 months) and Tenants B (8 months) compared to Australian Average. Item

A Water Use (L)

A % ofTotal Water Use

A % of Indoor Water Use

B Water Use (L)

8 % of Total Water Use

B% of Indoor Water Use

Australian Average % Total Use

Outdoor Use

214 620

51%

616 464

74%

205 130 77 015 46720 42 340 15 695 10 585 9 490 3 285

49% 18% 11% 10% 4% 3% 2%

156 448 30 689 18 458 51 975 43 481 9152

26% 5% 3% 8.5% 7.5%

N/A N/A

44%

Indoor Use Showers and Both Kitchen Sink Toilet Washing Machine Dishwasher Laundry Tub

N/A N/A

Zip Hot/Cold Top

1%

37% 23% 21% 8% 5% 4% 2%

1092 l 601

1.5% 0.2% 0.3%

19.5% 12% 33% 27.5% 6.3% 0.7% 1%

56% 20% 5% 15% 10% 3% 3%

N/A

Australian overages adapted from ABS /2004)

refereed paper

water

FEBRUARY 2006 59


on-site treatment water use skews the percentage results. Tenants B are more water efficient in the showers and baths than Tenants A and the Australian average. Toilet usage is very much dependent of the individual; however the flow-meter data showed that both sets of tenants used the 3L/6L flush in much the same pattern and that the differences in usage figures was not a result of inefficient use of the flush system. Tenants A used the kitchen sink m uch more than the Australian average, while Tenants B volumes were similar to the Australian average. For T enants A the washing machine only used 8% of the indoor water and 2. 3% of the total electricity, while for T enants B the washing machine used 27.5% of the indoor water and less than 6% of the total energy. It could be seen by the flow meters that the majoriry of the washing loads conducted by Tenants B were hot-water washes. This accounted for the bulk of the hot-water used by these tenants. While there is a debate about washing machine designs in the Australian water industry, the data from Research House show that washing machines are only responsible for a small amount of the total resource use for this specifi c dwelling. With the refrigerator using 14% (Tenants A) and the hot water system 13.5% (T enants A) of the total energy usage there may be more benefit in seeking energy efficiency from the infrastructure that uses the most energy rather than focusing on small percentage energy savings from items such as the washing machine and the dishwasher. The dishwasher used more energy than the washing machine and significantly less water (with both groups of tenants); it is thought that the difference was due the heating of the water in the dishwasher. The amount of water used by the Tenants A and B in the dishwasher was similar and compared closely to the Australian average; especially if the skew towards outside water use by Tenants Bis taken into account. The amount of electricity used by the dishwasher increased during the tenancy of Tenants B to almost do uble the previous amount. As water use fig ures were similar between the two groups; wash settings on the dishwasher must have been altered to account for the increase in electrical usage. The laundry tub was used more by Tenants A than by Tenants B, even though the washing machine was used 3.5 times more often by Tenants B. This once again highlights the d ifferences that user patterns can create. The Zip hot/cold water tap was used infrequently by both groups of tenants. The Zip hoc/cold water tap used only 1% or less of the water but required

60 FEBRUARY 2006 water

Table 5. Daily Wastewater Production Per Capita at Resea rch House com pared to

EP. Research House

Average Daily Total Water Use

Average Daily Indoor Water Use

Average Daily lndoorPer/ Person Water Use

Standard Equivalent Person (EP) Water Use

Tenants A

1150 L

Tenants B

3181 L

562 644

120 L 125 L

250 L 250 L

more electricity than the washing machine and the dishwasher put together (Tenant A data). It cost $70/year to run although the cost of this may have been offset as the refrigerator was not used to chill water and no kettle was required (QG 2005). Whether $70 worth of electricity would have been used to boil water in a kettle or to chill water in a refrigerator is unknown. The daily water usage per capita at Research House is of interest where sustainable housing design and integrated water management is concerned. The water supply and wastewater treatment requirements of urban developments are based on an Equivalent Person (EP) calculation. While there is a variety of different definitions for the exact volume of an EP one standard defi nition is that one EP equals 250 L of wastewater. The fact that various State Governments and Local Govern ment Authorities in Australia have slightly different definitions of EP has caused considerable confusion and the h istorical and scientific basis for the calculation of EP is not well known. The data from Research House show that o n a d aily per capita basis the volume of indoor water use from which wastewater will be produced is only 120 L for Tenants A and 125 L for Tenants B (see Table 5). The figures from Table 5 show that while the average daily use between the tenants groups is significantly different, the indoor water use is much closer, and the water use per person almost identical. When the differences in user patterns between Tenants A and B shown in Table 4 is considered the similar per person indoor water use volumes is remarkable. The water efficient infrastructure appears to keep overall indoor water usage relatively low, even with markedly different user patterns. The average daily total water use is strongly infl uenced by the amount of water used outside. As all of the outside water use measured at Research House was from the potable reticulated supply, potentially large savings of drinking water would be possible if recycled water was used for safe outside use.

Resource efficient infrastructure and its widespread acceptance by Government authorities and the general public are relatively new. While some organisations have altered EP values for resource efficient developments this has been done on an adhoc basis with very little consistency. The indoor water use volumes do not take into account potable use and spillage so the actual amount of wastewater produced per capita/day would be smaller. A reassessment of the EP calculation and how it applies to resource efficient designs needs to be undertaken. This process needs to occur o n a national basis and be applied co nsistently. Wastewater treatment systems, whether they are part of a reticulated sewage treatment plant or an on-site system are not effi cient, economic and may not supply quality treatment if they are over-sized for the required task. It is important to note that basing a new EP volume on bench-top studies without evaluating the impacts of people's user patterns and behaviours would not produce a realistic alternative. A ' Smart House' needs to be part of a 'S mart Development' and designing new resource efficient houses without reassessing the parameters used to design water supply and wastewater treatment is not a sustainable practice.

Conclusions Research H ouse will be a valuable tool for the long-term assessment of resource efficient sustainable ho using design. It is hoped that the continui ng information will be important in determining whether infrastructure maintains the same level of water and energy efficiency over time, or if it degrades in performance, and if so at what rate. Examinations of the infrastructure will be conducted when the house is vacant between tenants so that the exact volumes used (per minute or otherwise) can be calculated. The multiple data collection points have reduced the need for theoretical water and energy usage calculations within the house and provide real-time infrastructure specific information. The data collection computer and sensors are in the process of being upgraded and renewed. The changing

refereed paper


on-site treatment tenancy patterns allow fo r appraisals on usage patterns and behavioural differences of the general public. le was clearly shown char che infrastructure was used very differently by Tenants A and B although per capita usage was near identical. T he ability co make precise per capita calculations and compare them with yearly total use figures allows for some realistic field analysis of potential new EP calculations fo r sustainable developments. Data fro m dwellings such as Research House have the ability co provide relevant information for the long-term sustainable plan ni ng of Queensland's housing development. It would be in teresting co see if education sessions with the tenants, for example after 6-months tenancy, would have any impact on the water usage fig ures, especially in regard s co che ou tside water use volumes and whether any changes in user patterns can be maintained over time o r be shore-lived.

Acknowledgments T he authors would like co acknowledge the sponsors of Research House and the Built

Environment Research House Team fro m che Q ueensland Department of Public Works; Michael Ball as Project Director and Roslyn Edols (Research Assistant). We would also like co thank the Engineering and Physical Systems Departmen t of che Central Queensland University, Barry Hood, Billy Sinclair, Rob Lowry and Donna Hobbs.

The Authors

Ben Kele (b.kele@cqu.edu.au ) is a PhD cand idate with rhe Plane Sciences G roup (PSG) of the Central Queensland U niversity (CQU), Professor Peter Wolfs is Associate Dean of Engineering, Nicola Orr a research officer, Ian Tomlinson an Engineering Technician (and the most water effi cien t of the au thors), and Professor David Midmore is D irector of PSG CQU. Kevin Hoffman is an electrical engineer wirh Queensland Department of Public Works.

References ABS (2004) In Cat. No. 4610.0Auscralian Bureau of Scarisrics, Canberra.

Bearty, R., O 'Brien, S. and Smart, B. (2005) In Ozwater Convention and Exhibition AWA, Brisbane. Choe, C. and Fraser, I. (I 998) The Australian Journal ofAgricultural and Resource Economics, 42, 269-302. Gardner, T. and Millar, G. (2003) In On-Site '03 (Eds, Patterson, R. A. and J ones, M. J.)

University of New England, Armidale, pp. 145-152. Icke, J., VanDerBoomen, R. M. and Aalderink, R. H . (I 999) Water, Science and Technology, 39, 21 1-218. Kele, B., Midmore, D. J., Harrower, K. , Hood, B., McKennariey, B. , Doyle, G ., Saunders, D. G. and Macey, P. (2003) In Water Recycling Australia - 2nd National Conference (Eds, Gardner, T. and McGarry,

D.) Ausrra!ian Warer Association, Brisbane. QG (2004) Queensland Government; Queensland Depamnenc of Public Works and Queensland Depamnenr of Housing, Brisbane. lmp://www.housing.qld.gov.au/ in iria rives/ research house/pub licario ns/ index.hrm QG (2005) Queensland Governme nr; Queensland Deparcmenr of Public Works and Queensland Deparrmenr of Housing, Brisban e. hrcp://www.housing.qld.gov.au/ in iria rives/ research house/ pu bl ications/ index.l1rm

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refereed paper

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RAPID SCREENING TEST FOR MICROCYSTIN IN WATER Z Moore, C Ferguson, V Sen, T Flapper Abstract T he protein phosphatase inhibition assay (PPIA) is an enzyme-based colorimetric assay for the detection of the blue-green algae toxin microcystin. The sensitivity and relative specifici cy of the assay makes it a suitable screening cool for the rapid detection and quantification of microcysci n equivalents in water.

Introduction Warm climate condi tions and eu trophicacion of water bodies predispose waterways to an increased frequency of cyanobaccerial blooms. (Figure 1). The prolonged drought and continued urbanisation are highlighting the need fo r the sustainable use of surface water supplies as sources of drinking water. Cyanobacteria and their toxins, especially microcystins have been recognised as the most significant drinking water quality issue in relation to cyanobacterial blooms in sou th-eastern Australia (NH&MRC and NRMMC 2003) . However, the unpredictable nature of bloom toxicity makes it difficul t to predict likely toxin concentrations in surface waters.

Figure 1. Microcystis bloom in the ACT.

It enables the microcystin toxicity of a sample to be measured as MCLR equivalents. concentration of total microcystin while the World health Organisation's (WHO) gu idelines for drinking-water quality (WHO 2004) are specific to microcystinLR (MCLR) It is also the only microcystin for which sufficient toxicity data are available fo r guidel ine derivation. The WHO guidelines specify MCLR because ir

is among the most frequen tly detected and most toxic microcystin congeners. Since populations of Microcystis produce an array of microcystins with varying toxicity the Australian guidelines also specify that toxicity be expressed as equivalents of MCLR. The current Australian drinking water guideline is 1.3 Âľg/L MCLR toxicity equivalen ts (NH &MRC and NRMMC 2003).

Microcystins are hepatotoxic cyclic peptides produced by a variety of blue-green algae such as Anabaena, Nodularia, Nostoc, Oscillatoria, and Microcystis. They exert their toxicity by damaging mammalian liver function as a result of their inhibitory effect on protein phosphatases (Figure 2), which are essential for maintaining cellular integrity. Inhibition of these enzymes ultimately results in rupture and haemorrhaging of the liver. It is now well known char even low concentrations of cyanobacrerial toxins in drinking, agricultural and recreational water can pose serious health problems. Microcysrins promote the growth of tumours in animals studied in rhe laboratory, and rhe significance of this for humans, who may be subject to chronic exposure via drinking water, is nor known. The current NHMRC/ARMCANZ Figure 2. Diagrammatic representation of the process of protein dephosphorylation and the inhibition by guidelines (NH&MRC and hepatotoxins. NRMMC 2003) refer to rhe

62 FEBRUARY 2006

water

A number of methods have been developed fo r the detection and quantification of microcystin. These include toxicity-based assays and instrumental analyses as well as enzymatic procedures. While toxicity based assays lack specific ity and sensitivity, instrumental analyses, especially HPLC, are by far the most commonly used owing to their high level of accuracy and precision. However, these procedures require extensive sample preparation and clean-up, adding to the cost. Immunological methods such as ELISA may lack the required specificity and could give false negative results.

refereed paper


algal toxins Method The enzyme based colorimetric procedure was developed by the CRC for Water Q uality and Treatment as described by H eresztyn and Nicholson (2001). The protein phosphatase inhibition assay (PPIA) is an enzyme-based colorimetric procedure co detect cycl ic peptide heparoroxins, which includes over 60 variants of microcystin as well as the nodularin group of roxi ns. T he assay is based on the ability of these heparoroxins co inhibit the enzymes responsible fo r the de-phosphorylation of intracell ular proteins The rest utilises p-nitrophenyl phosphate as a substrate and protein phosphatase-2A (PP2A) as the target enzyme. The main advantage of this procedure is chat it can be used directly for detection of low levels of roxins without sample pre-concentration or clean up. Although the procedure can have the drawback of overestimating roxin concentration due to interfe rence from non-algal protein phosphatase inhibirors, its sensitivity and relative specificity makes PPIA suitable as a primary screen for MCLR eq uivalents in water suppl ies. Any positive results may be followed up by HPLC for confirmatio n. T he ai m of chis study was co assess the efficacy of the described assay (H ereszryn and Nicholson 2001 ) with a range of sample matrices co determine its com mercial applicabili ty as a screening rest fo r MCLR T he optimised assay utilises l 00 µL of sample (o r standard) combined with 10 µL of enzyme solmion (co ncentration 0.02 units) in a 96-well flat-bottomed microplare well. The plate is placed in a microplare reader, shaken to mix the solutions and then incubated at 37°C fo r 5 minutes. A l00µL aliquot of substrate solution is then added to start the reaction and the plate is mixed and incubated at 37°C for up to 95 minutes. The colour is measured at 405 nm after 60, 75 and 95 minutes and the concentration of microcysrin calculated from the standard curve. All samples are analysed in triplicate. The microcystin inhibition (calib ration curve) (Figure 3) was plotted as percentage activity of PP2A relative to the co ntrol, versus microcystin concentration, where: PP2A activity (%)

=

Absorbancemndard - Absorbanceblank

10 0.0 1

0.1

Figure 3. Inh ibition effect of microcystin-LR on PP2A. region between 20 and 80% activity, was used. T he IC 50 was the toxi n co ncentration, which resulted in 50% activity (or inhibi tion). IC50 can vary over time and with different analysis batches. This is related to changes in the activity of the enzyme used and thus may be affected by age and batch variation. This should be carefully moni rored by analysis of standards in every sample batch and taking absorbance readings from 60 to 95 mrnures. Recovery efficiency of the assay was assessed using fi ve different water matri ces including effluent from a sewage treatment plant lagoon, a recycled water reservo ir, two recreational lakes and a storage reservoir. Samples were spiked with mLR to give final concentrations of 0.1 to 5 µg/L. Standard concentrations of MCLR were prepared in purified water and analysed for the preparation of a standard curve. Purified water blanks, sample blanks, and positive and negative controls were run with each assay. Blank

refereed paper.

readings were deducted from raw absorbance data to give the corrected absorbance measured as optical density (OD) at 405 nm. Logw of the corrected absorbance was plotted agai nst standard concentrations to create the curves to determi ne recovery. Repeatabili ty of the assay for MCLR quantification was evaluated according co NATA guidelines (2003).

Results and Discussion The working range of the optimised assay was between 0.4 and 1.6 µg/L MCLR equivalents (Figure 3). Although these results are a li ttle above the levels of sensitivity achieved in cited publications, the results were reproducible. Samples that exceed the upper assay limits can be diluted and re-analysed while th e detection of low concentrations of toxin enables the detection of levels b elow the Australian drinking water guideline value of 1.3 µg/ L.

0.60 E C:

0.40

It)

0

::!. 41 0

0.20

C:

-e'" 0

0.00

"'

.Q

'" -c ~ 0

-0.20

~

00 0)

..2

-0.60

Absorbanceconrrol - Absorbanceblank To increase the accuracy in determining roxin concentrations, only the linear region of the calibration curve, i.e. the

10

MCLR (ug/L)

cone MCLR (ug/L) ~

RO water

-

Site 1

- .-site2

~

Site3

~

Site4

-.!I-Site 5

Figure 4. Efficiency of extraction of microcystin LR from spiked matrices.

water

FEBRUARY 2006

63


algal toxins The results of the effects of different Table 1. Quality contro l. matrices on the recovery of MCLR QC (mLR} ug/L From MP Reader Assay No concentrations ranging fro m 1-5 pg/Lare shown in Figure 4. Mose 0.984 1 1.0 data points can be closely correlated 0.757 1.0 2 at different MCLR concentrations. 0.967 1.0 3 The high MCLR equivalent 1.17 1.0 4 concentrations in sample 1 are indicative of high levels of Conclusion MCLRequivalents present in che sample in addition co che spike. This can be observed The PPIA assay was used successfully co in che 0 pg/L data point in Figure 4, which quantify the amount of spiked microcystinhad a lower absorbance than all ocher LR equivalents within a variety of water samples. This sample point is fro m a sewage samples. It is a rapid and efficient method treatment plant lagoon, which has a history that enables che microcystin toxicity of a of Microcystis blooms. An analysis of sample co be measured as MCLR variance gave no evidence of a significant equivalents. Alcernacive methods such as effect of spike concentration on recovery (p high performance liquid chromatography >0.5) and there was no evidence of matrix and capillary electrophoresis offer the interference on recovery efficiency (p>0. l). advantage of coxin profiling but PPIA is Uncertainty measurements at 95% able co indicate the coral toxicity (in confiden ce limits included method bias, relation co the inhibition of rhe regulatory precision and purity of standards based on process of dephosphorylarion) of a sample, manufacturer's specifications. The which is ultimately the concern of water coefficient of variation within assay duplicates was less than 25% (Table 1). authorities.

The Authors Zoe Moore is Research Microbiologist, Dr Christobel 2.54 Ferguson is Principal Research Scientist, Dr Visalakshi Sen is 23 .9 Senior Biologist and Dr Therese 18.6 Flapper is che Director of Research 7.3 and Development at ECOWISE Environmental, Fyshwick ACT 2069, Email: zmoore@ecowise.com.au

%CV

References Hereszryn, T. , and B. C. Nicholson. 200 1. Determination of Cyanobacterial Heparoroxins d irectly in water using a protein phosphatase inhibition assay. Water Research 35 (13):3049-3056. NATA Technical C ircular #2: December 2003. Uncertainty of Measurement in Biological, Forensic, Medical and Veterinary Testing. N H &MRC, and NRMMC. 2003 . Australian Drinking Water Guidelines. Canberra: National H ealth and Medical Research Council and Natural Resource Management Min isterial Council. WHO. 2004. Guidelines for Drinking-water Quality. 3rd edition ed. Vol. I Recommendations. Geneva: World H ealth O rganisation.

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refereed paper


CHLORINATION OF FOUR MICROCYSTIN VARIANTS L Ho, S Rinck-Pfeiffer, K Craig, G Newcombe

Ii

Abstract The p resence of microcystin toxins in d rinking water is highly undesirable as they have the propensity to adversely affect human health. Consequently, effective removal of these tox ins from water is paramount. After removal of intact cells by coagulacio n/ sedimen cation/ fil cration, removal of d issolved microcyscins by adsorption onto activated carbon and/or oxidation by chlorine can be effective under certain conditions. This study has shown that some microcyscin variants are considerably less reactive wi ch chlorine than ochers, with the natural organic material (NOM) and pH of the waters tested being significant factors in these reactions. For Myponga and Morgan waters, CT values of 6.9 mg min L-1 and 30.7 mg min L-1 were required for oxidation of the most resistant microcyscin variants to below the WHO guideline value of 1.0 µg L-1• This study indicates chat for some water sources it is important to d etermine the speciacion of the microcyscin variants to optimise chlorination practices.

MCLA is the most difficult microcystin variant to treat. Introduction Among the most common of the cyanobaccerial toxins are the microcyscins, a group of over seven ty hepatotoxins produced predominantly by species of Microcystis, Anabaena, Nostoc and Planktothrix (Carmichael, 1992; Codd, 1995; Keil et al., 2002; Acero et al., 2005). Microcystins all contain a ls-amino acid, Adda (3-amino-9-mechoxy-2,6,8-crimechyll 0-phenyldeca-4,6-dienoic acid) which is largely responsible for their toxicity (An and Carmichael, 1994), but vary in cwo of their ocher amino acid constituents which is displayed in the letters following "microcyscin " in the name of the toxin. For example, microcyscin-LR (MCLR) has a Leucine amino acid and an aRginine ami no acid in the variable positions. The properties and structures of four common microcyscin

refereed paper

CIIJ 0

mlcrocystln-LA

ll~COOII

IIN 113c.....,_

f 'D=NII 112

0

JI

HJ

i!L(x:i:Lt_ H ,I, - , 111

~;,c/\. ! .f\

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mlcrocystln-YR

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O

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Figure 1. Structu res of mic rocystin-LR, -LA, -RR a nd -YR. variants are presented in Table 1 and Figure 1, respectively. These compounds may be released from lysed algal cells, so although coagulation/ sedimen tation/filtration will remove the cell matter it is inadequate for the removal of these d issolved microcyscins (Hoffman, 1976; Himberg et al., 1989). Therefore, water suppliers need to consider using alternative treatment strategies or optimising existing treatment strategies for their removal. In the majority of Australian water treatment planes (WTPs) two treatment strategies can be implemented for the removal of microcysti ns: powdered activated carbon (PAC) and chlorination. For the effective treatment of these toxins, it is extremely important fo r the water suppliers to have confidence in the application of both processes for the treatment of these compounds. The PAC/chlorination multi-barrier treatment approach was considered to be

suffi cient for the removal of these toxins. However, recent studies by Cook and Newcombe (2002) have indicated chat some microcys cin variants may not be well removed by PAC. T he authors indicated chat PAC was very effective fo r the removal of microcysci n-RR (MCRR) and -YR (MCYR). However, for MCLR, they determi ned chat PAC may be a relatively expensive op tion. Furthermore, for microcystin-LA (MCLA), the a uthors concluded chat PAC would not be recommended, as the compound was not well adsorbed. Therefore, water suppliers need co optimise the final barrier stage of chlorination for the effective removal of all microcyscin variants. Contrary to the results reported by H offman (1976), and Himberg et al. (1989), chlorine has been demonstrated as being effecti ve for the oxidation o f microcyscins (Nicholson et al., 1994; Tsuji eta!., 1997). Nicholson et

Table 1. Properties o f four microcystin variants, MCLR, MCLA, MCRR a nd MCYR (adapted from Sivonen and Jones, 1999) .

Variant (MCXZ)

MCLA MCLR MCRR MCYR

Variable Amino Acids X z Leucine

Alanine

Leucine

Arginine

Arginine

Arginine

Tyrosine

Arginine

LOSO•

Molecular Weight (g mol-1)

50 50 70 600

909 994 l 037 l 044

*Toxicity measured by i. p. mouse (pg/kg)

water

FEBRUARY 2006 65


algal toxins al. (1994) showed that provided a chlorine

Table 2. First order rate constants for chlo rine decay in M yponga (MYP) a nd Morgan (MOR} waters.

residual o f at least 0 .5 mg L· 1 was present after 30 minutes contact time, chlorination was effective in the oxidation of MCLR. Similarly, Tsuj i et al. (1997) showed that a chlorine dose of 2 .8 mg L· 1 for a contact time of 30 minutes was sufficient for 9 9% oxidation of M CLR. However, these experiments were carried our under condi tions far removed fro m chose experienced in a WTP, and to dare, no data on required CT values for the removal of a range of microcystins in typical treated water qualities have been reported. T he CT concept (where CT is the amount of chlorine exposed, C at a specific reaction rime, T) is generally used to assess the efficacy of a disinfectant for the inactivation of disease-causing organisms. Consequently, it is envisaged char chis concept can also be used to assess the effectiveness of ch lorine fo r effective oxidation of rhe microcysrins.

MYP 5.93

0.5 1.0 1.5

X l 0·3 X l 0·3

1.99 5.47 X 10·4

MOR 1.61 X 10·3 5.76 X 10·4 1.98 X l 0·4

Bioscience Pry Ltd , Australia); MCLR and M CLA were co-extracted from a natural b loom of Microcystis aeruginosa that occurred in the Torrens Lake in South Australia durin g the summer of 1998-99. The isolation procedure involved freezethawing the bloom material in water and methanol, followed by preparative reverse phase flash chromatography and preparative high performance liquid chromatography (HPLC).

Similar oxidation reactions could be expected from their structures; however, recent PAC adsorption experiments (Cook and Newcombe, 2002) have shown char there are differences between the variants char can only be explained by structural differences, and these could also affect the chlorination reaction. At present, minimal studies have been conducted on the treatment of multiple microcystin variants which are more realistic since most microcystin-producing blooms yield multiple variants.

Chlorination experiments A chlorine stock solution was prepared by bubbling gaseous chlorine through Milli-Q water in a glass flask. The flask was then sealed and stored at 4°C overnight prior to use. Typical chlorine stock solution co ncentrations ranged from 3000-5000 mg L· 1 as free chlorine. All chlorination experiments were conducted in 500 mL glass amber b ottles at room temperature (20±2°C). For chlorine d ecay experiments, waters (containing the microcysrins) were dosed with chlorine and aliquot samples taken at various time intervals fo r free chlorine residual determinations usi ng the DPD-FAS titration method described in Standard Methods (APHA et al., 1998) .

Aims and Objectives of the Study T he main objective of th is study was to determine whether microcystin variants, MCLR, MCLA, MCRR and MCYR, were different in their behaviour when chlorinated at various doses. Another objective was to explore rhe CT values required for confident oxidation of the microcystin variants under conditio ns expected in a typical WTP; th us conventionally created waters were o btained from two South Australian WTPs: Myponga (coagulation/d issolved air fl otation/filtration) and Morgan (coagulation/ ~ sedimentation/filtration) which differ both in NOM content and coagulation pH. Waters were sampled after filtration and prior to disinfection.

First Order k (s·1)

Chlorine Dose (mg L·1 as Cl2)

For microcystin chlorination experiments, waters were spiked with approximately 20 µg L· 1 of each microcystin variant prior to chlorination. MCRR and MCYR were chlorinated in individual experiments.

1.5

Myponga • 0.5mgL·' • 1.0mgL·' ,. 1.5mgL·' Morgan 0.5mgL·'

1.0

· 8-

1.0mgL·'

~

However, MCLR and MCLA were chlo rinated in the same experiments since both variants had been co-extracted and concentrated in the same spike solution. Chlorine was added from the chlorine stock solution to obtain the desired doses. Samples were quenched at various rime intervals with sodium sulphite at a stoich iometric ratio specified in Standard Methods (APHA et al., 1998). Selected microcysrin decay experiments were co nducted in duplicate.

Analytical methods Prio r to analyses, water samples were filtered through 0.45 µm membranes. The pH of the waters was measured on a PH I 50 pH merer (Beckman Instruments, USA). Dissolved organic carbon (DOC) measurements were made on an 820 Total Organic Carbon Analyser (Sievers I nstruments Inc, USA) while UV absorbance at 254 nm (UV254) was measured in a I cm quartz cell using a UV/VIS 9 18 Spectroph otometer (G BC Scientific Equipment Pry Ltd, Australia) . Prior to HPLC analysis, microcysrins were con centrated from sample waters by C l8 solid phase extraction according to the methods d escribed in Nicholson et al. (1994) . A H PLC system consisting of a 600 pump controller, 717 plus autosampler and 996 photodiode array detector {Waters Pry Ltd, Australia) was employed. A 150 x 4.6 mm Luna Cl8 column (Phenomenex, Australia) was used with a pore size of 5 µm. A 50 µL sample injection was utilised at a fl ow rate of 1 mL min· 1. Two mobile phases were used for the gradient run (30 % acetonitrile/0.05% rriflu oroaceric acid and 55% acetonitrile/0.05% trifluoroacetic acid). Concentrations of MCLR, MCRR and MCYR were determined by calib ration of the peak areas (at 238 nm) with that of external standards purchased from Sapph ire Bioscien ces (Sapph ire Bioscience Pry Led, Australia). All MCLA concentrations were expressed in terms of MCLR equivalents. The HPLC method has a detection limit of 0.025 µg L· 1• Microcystin recoveries were > 95% with a relative p recision of 10% .

'·:,:4

~ " · 4·········· L, ..........,,......... ...

Experimental Procedures Materials and reagents Four microcystin variants were used in this study: M CRR and MCYR were purchased from a commercial supplier (Sapphire

66 FEBRUARY 2006

water

0.0 -1----:;:'---- -0 10

'D

:;:.-~- ~ ~- - ~ ~ - ~ ~ ~ 60 30 40 50 20

Time (minutes)

Figure 2. Chlorine concentration as a function of time in Mypo nga and Morgan waters.

Results and Discussion Chlorine decay C h lorine decay experiments were conducted for Myponga and M organ waters, spiked with the microcystins at a concentration of 20 µg L· 1, using chlorine doses of 0.5, 1.0 and 1.5 mg L· 1 as Cl 2 . Figu re 2 shows rhe chlorine residual as a function of time in the two

refereed paper


algal toxins waters. T here was a significant difference in the consumption of chlorine in the two waters, with a higher consumption evident in Myponga water as shown in the firstorder rate constants for the consumption of chlorine in Table 2. The differences are due to a number of water quality factors, the most important being the natural organic material (NOM) present. Table 3 shows char Myponga water exhibited higher DOC, UV254 and SUVA values than Morgan water. Concentration and character of NOM influence the reaction with chl orine as NOM co ntaining a higher proportion of conjugated and subscicuced aromatic moieties (and co nsequently light absorbing chromophores) is more susceptible to chlorine arrack (Reckhow et al., 1990; Korshin et al., 1997). The two waters had also been coagulated at different pH values. The lower pH of Myponga water would also influence the reactivity of chlorine since the acid-base equilibrium favours hypochlorous acid (HOC[), a stronger oxidant than the hypochlorice ion (CIO·) which is the major species of chlorine present at pH > 7.5. T he ratio of HOC[ to CIO· at pH 6.3 is 16:1 whereas at pH 7.9 it is 0.4: I. The higher reactivity of HOC[ with NOM may also contribute to the higher chlorine consumption in Myponga water. Chlorination of microcystins in Myponga water

Chlorination of all microcyscin variants was co nducted in Myponga water using doses of 0.5, 1.0 and 1.5 mg L· 1. Figure 3 shows che oxidation of the microcyscins as a fun ction of CT at two of the doses, 0.5 and 1.0 mg 1· 1• No observable di fference was eviden t in che oxidation of MC1R, MCLA and MCRR using a chlorine dose of 0.5 mg 1· 1• However, MCYR was the most susceptible to chlorine accack with up to 5 1% oxidised. When a chlorine dose of 1.0 mg L· 1 was employed, distinct differences were evident in the chlorination of each variant with che ease of oxidation following the trend: MCYR>MCRR>MC1R>MC1A. MCYR was again the easiest variant co oxidise as a CT of 2.3 mg min 1- 1 was required fo r oxidation of chis variant co below HPLC detection. T his is in contrast to MCLA which required a CT of 4. 1 mg min L· 1 for on ly 61 % oxidation. A chlorine dose of 1.5 mg 1· 1 with a reaction rime of 10 minutes was sufficient for the oxidation of all microcyscin variants to below the WHO guideline value of 1.0 µg L- 1 (data not shown}. This equates to a CT value of 6.9 mg min 1-1 which is 1 co 4 orders of magnitude lower than che CT values required for 99% inactivation of

refereed paper

0.5 mg L"1 100

100

-

110

j

80

~

70

0 .S:

EIO

-~

<40

• -MCLR •-MCLA • - MCRR • - MCYR

90

j

80

;2

70

0

I '°

::;; "i:

~

a.

30 20

10

0.0

02

o...

o.s

o.e

10

2

1.2

3

CT (mg min L"1)

CT (mg min L"1)

Figure 3 . Mic rocysti n oxidation as a function of chlorine exposure (CT) usi n g chlori ne doses of 0.5 and 1.0 mg L·1 in Myponga water. Error bars represent selected experiments conducted in d uplicate.

pathogens such as Giardia, Legionella, and Cryptosporidium Oacangelo et al., 2002). O nly small di fferences were observed in che oxidation of che microcystin variants using a chlorine dose of 1.5 mg 1-1 due to the rapid oxidation of all variants. Chlorination of microcystins in Morgan water

Si milar chlorination experiments were conducted in Morgan water. Results are presented in Figure 4. A 0.5 mg L· 1 chlorine dose, with a reaction time of 5 minutes, was found to oxidise MCYR to below HP1C detection. T his equates to a CT value of 1. 3 mg min L· 1• In contrast, incomplete oxidation of the other three variants was evident, similar to the results in Myponga water. For a chlorine dose of 1.0 mg L· 1, the oxidation trends of the variants were identical to chose reported in Myponga water. MCYR was again the most susceptible to chlorination fo llowed by MCRR which required a CT of 9.4 mg min 1· 1 (1.0 mg L· 1 dose for 20 minutes) for oxidation to below the WHO guideline value. In contrast, MC1A was nor completely oxidised withi n the contact times used for che 1.0 mg L· 1 chlorine dose.

A chlorine dose of 1.5 mg 1· 1 with a reaction time of 40 minutes was sufficient for oxidation of all che microcyscin variants to below che WHO gu ideli ne val ue (data not shown}. T his equates to a CT value of 30.7 mg min L· 1, which is higher than che analogous CT value for Myponga water. Furthermore, a 1.5 mg 1-1 chlorine dose resulted in only small differences in the oxidation of che microcyscin variants due to rapid oxidation of each variant, si milar to the findings with Myponga water. Comparison of microcystin chlorination in the two treated waters

The differences in the chlorination of the variants have not been previously reported since most of the work to date has foc ussed primarily on MCLR. A possible explanation for these differences may lie in the variable amino acids of each variant. The detection of microcystins by HP1C (at 238 nm) is considered to be due to che conjugated diene of the Adda moiety. This is a prime site fo r chlorine accack, which while destroying Adda, also removes toxicity (An and Carmichael, 1994). However, MCYR, MCRR and MCLR contain other potential reaction sires, in particular, the variable

__ ,,__,,_ ,,

0.5 mg L"1

1.0 mg L·'

,,

100

100 00

110

1

j

80

~

70

C

80

0

l

!

-•-MCLR - - MCLA - • - MCRR

C

~

a.

.!.! ::ii

i

JO

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20

10 0

10

15

CT (mg min L"')

20

25

30

0

10

15

20

CT (mg min L"' )

Figure 4. Microcystin oxidation as a function of ch lorine exposure (CT) usi ng chlorine doses of 0.5 and 1.0 mg L-1 in Morgan water. Error bars represent selected experiments conducted in duplicate.

water

FEBRUARY 2006 67


algal toxins amino acid side chains. MCYR con tains a tyrosine group with a phenolic moiety which would be expected to be highly reactive with chlorine (Reckhow et al., 1990; Gallard and von Gunten, 2002). In addition, MCYR contains an arginine group which would also be highly susceptible ro chlorine attack. Studies have indicated chat chlorine (through the reaction of HOC[) has a high reactivity with phenols and amino acids (Priitz, 1998; Pattison and Davies, 2001; Gallard and von G unten, 200 2). Therefore, the presence of these groups may account for che high race of oxidatio n of MCYR. Similarly, MCRR contains two arginine groups which could also make it highly susceptible ro chlorine attack. T he same reasoni ng would be the case for MCLR, although it only contains one arginine group with the other variable amino acid being leucine. MCLA is the o nly variant that does not contain argi nine, and hence may not be as susceptible to chlorine attack at sites other than Adda.

Table 3. DOC, UV254, SUVA, and pH values for M yponga (MYP) and Morgan (MOR) w aters prio r to WTP chlorination. Water

DOC (mg L·l)

MYP MOR

5.0 2.9

68 FEBRUARY 2006 water

·x

70

C:

60

0

~ >,

::;

Variant

Chlorine Dose (mg L·1)

Contact Time (mini

CT (mg min L· 1)

MYP

MCLA MCLR MCRR MCYR

1.5 1.5 1.5 1.0

10 10 5 5

6.9 6.9 4.2 2.3

MOR

MCLA MCLR MCRR MCYR

1.5 1.5 1.0 0.5

40 10 20 5

30.7 10.0 9.4 1.3

content and also the pH. At low pH (pH < 7.5), HOC! is the dominant reacting species of chlorine whereas at high pH (pH > 7.5), CIO·, a much weaker oxidant, is the dominant species. Since the pH val ues of the coagulated Myponga and Morgan waters were 6.3 and 7.9, respectively, then greater oxidation would be expected in Myponga water. Similar observations were made in a study by Nicholson et al. (1994), where decreased toxin removal was observed at higher pH as a result of the decreasing concentration of H OCl.

Practical implications from this study Even with the spiked concentrations of 20 µg L· 1, a chlorine dose of 1.5 mg L· 1 with a reaction t ime of 40 m in utes was sufficient for efficient oxidation of all the microcystins in both waters. Since optimised coagulation/ sedimentat ion/filtration will remove up to 98% of total microcystin present within

I

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intact cells it is unlikely that levels of d issolved microcystin above 5 µg L· 1 would reach the chlorination point in a WTP. Therefore, in practical situations where the DOC concentration is 5 mg L· 1 or lower a chlorination dose of 1.5 mg L· 1 should be suffi cient to reduce the d issolved microcyscin concentration to below the WHO guideline value of 1.0 µg L· 1• The CT values correspond ing to rhese conditions were 15.9 and 30.7 mg min L· 1 in Myponga and Morgan waters, respectively. T hese values would be within the CT range applied at many WTPs. However, previous recommendations that a residual of 0.5 mg L· 1 after 30 minutes contact would be sufficient to oxid ise all microcystins (i.e., a CT> 15 mg min L· 1) should be treated with caution. In this study, in Morgan water, the minimum recommend ation would have resulted in MCLA remaining in solution at a concentration above the WHO guideline value.

,,. ,,.

Conclusions

I I Q

40

/

C: Q)

6.3 7.9

Water

0

e .Sol

1.9 1.4

0.093 0.040

W HO guideline value (1.0 µg L·1) in M yponga (MYP) a nd Morgan (MOR) waters.

Q)

"' 'o

pH

Table 4. Chlorination cond itions required for oxidation of microcystins to below the

A comparison of che chlorination of microcystin as a functi on of CT for Myponga and Morgan waters is illustrated in Figure 5. Only CT data from the 0.5 and 1.0 mg L· 1 chlorine d oses are shown d ue to rapid oxidation of the microcystins using the 1.5 mg L· 1 chlorine dose. In most cases, a strong linear relationship exists between the percent oxidation of the variants and CT. However, for MCRR, poor correlation coefficients (R2) were observed for bo th waters. It is unclear why this is the case although a possible explanation could be d ue to the co mpetitive effects between chlorine and NOM and chlorine and MCRR. It is possible that MCRR and NOM may have formed an intermed iate compound at the lower chlorine dose, making it more resistant to oxidation. T he results also suggest that the oxidation mechanism for MCRR may be different to that of the other 100 microcystin variants. Further work is required to subsrantiate these 90 ,, 80 contentions. For a given CT, a higher degree of oxidation of the microcystins was evident in Myponga water (except for MCYR which was readily oxidised in both waters). This is confirmed in Table 4 which lists the conditions required for oxidation of each of the microcystin variants to below the WHO guideline value. In general, higher CT values were required for effective oxidation of the microcystins in Morgan water compared with Myponga water. This can be related to the NOM

SUVA (L mg·1 m·1)

/

o /

/ /

..

~ MCLA (R' 0.98) MCLR (R' 0.96) MCRR (R' 0.80) MCYR (R' 0.91)

....

M2wn a

20 10 V

MCLA (R' 0.96) 2 MCLR (R 0.94) MCRR (R' 0.72) MCYR (R' 0.86)

0 0

10

15

20

25

CT (mg min L"')

Figure 5. Comparison of microcystin oxi dation in M yponga and M o rgan waters (correlation coefficients, R2 , a re presented in pa rentheses).

These results indicate that chlorination is an effective treatment option for the oxidation of a range of microcystins. However, it is important for water suppliers to be aware of which microcysci n variants are present in their water source since each variant may be oxidised to a d ifferent degree depending on interactions with other source materials (i.e., NOM). This work, along with previous work by Cook and Newcombe (2002), has shown that MCLA is the most d ifficu lt microcystin variant to treat, and if

refereed paper


algal toxins presen t in significan t amounts, additional PAC and chlorine doses would be recommended for its effective removal from drinking water.

The Authors Lionel Ho, the correspond ing author, is a Research Scientist at the Australian Water Quality Centre, SA Water Corporation, PMB 3, Sal isb ury SA 5 108 (Email: lionel.ho@sawater.com.au). Stephanie Rinck-Pfeiffer is the Research & Development Manager at U n ited Water International, Adelaide SA. Keith Craig is the Technical Director of Veolia Water Australia, Pyrmont, NSW. Gayle Newcombe is a Senior Research Scientist at the Australian Water Quality Centre, SA Water Corporation, Salisbury SA.

from a Planktothrix bloom and rwo laboratory strains. Water Research 36 (8), 2133-2139. Korshin G.V., Li C.-W. and Benjam in M.M. (1997) Monitoring the properties of natural organic matter through UV spectroscopy: A consistent theory. Water Research 3 1 (7), I 787-1795. Nicholson B. C., Rositano J. and Burch M.D. ( 1994) Destruction of cyanobacrerial peptide hepatotoxins by chlorine and chloram ine. Water Research 28(6), 1297- 1303. Parrison D .I . and Davies M.J. (200 1) Absolute rare constants for rhe react ion of hypochlorous acid with protein side chains and pepride bonds. Chemical Research in Toxicology 14(10), 1453-1464. PrUrz W.A. ( 1998) React ions of hypochlorous acid with biological substrates are activated

catalytically by tertiary amines. Archives of Biochemistry and Biophysics 357(2), 265-273. Reckhow D.A., Singer P.C. and Malcolm R.L. ( 1990) Chlorination of humic materials: Byproduct formatio n and chemical interpretations. Environmental Science & Technology 24(11), 1655-1664. Sivonen K. and Jones G. (1999) Cyanobacterial

toxim. In Toxic cyanobacteria in water: A guide to their public health and consequences, monitoring and management. I. Chorus and J. Bartram (Eds), pp. 41-111, E&FN Spon Publishing, London, U K. Tsuji K., Watanuki T ., Kondo F., Watanabe M.F., Nakazawa H., Suzuki M., Uchida H . and Harada K.-l. (1997) Stability of microcystins from cyanobacreria - IV. Effect of chlorinat ion on decomposition. Toxicon 35 (7) , 1033-1041.

References Acero J.L., Rodriguez E. and Meriluoto J. (2005) Kinetic reactions berween ch lorine and t he cyanobacrerial toxins microcysrins Water Research 39(8), I 628-1 638. An J. and Carmichael W.W. (I 994) Use of a colorimetric protein phosphatase inhibition assay and enzyme linked immunosorbenr assay for the srudy of microcystins and nodularin. Toxicon 32( 12), 1495- 1507. APHA, AWWA and WEF ( 1998) Standard

Methods for the Examination of Water and Wastewater, 20th ed. Parr 4500-03. American Public Health Association, American Water Works Association and Water Environment Federation, Washington, DC, USA. C armichael W.W. ( 1992) Cyanobacreria secondary metabolites - The cyanotoxins. journal ofApplied Bacteriology 72(6), 445459. Codd G.A. (1995) Cyanobacterial toxins: Occurrence, properties and biological significance. Water Science & Technology 32(4), 149- 156. Cook D. and Newcom be G. (2002) Removal of microcysrin variants with powdered activated carbon. Water Science & Technology: Water Supply 2 (5/6), 201-207. Gallard H. and von Gunten U. (2002) Chlorination of phenols: Kinetics and formation of chloroform. Environmental Science & Technology 36(5), 884-890. Himberg K. , Keijola A.-M., Hiisvirta L., Pyysalo H. and Sivonen K. (1989) The effect of water treatment processes on the removal of hepatotoxins from Microcysris and Oscillatoria cyanobacreria: A laboratory study. Water Research 23(8), 979-984. H offman ) .R.H . (I 976) Removal of Microcystis toxins in water purificarion processes. Water SA 2(2), 58-60. Jacangelo J .G., Parania N.L., Trussell R.R. , Haas C.N. and Gerba C. (2002)

Eliminates phosphorus from water bodies and breaks the algal cycle: • Reduces phosphorus concentration • Caps sediments • Prevents remobilisation of phosphoru s • Stable at varying pH • Stable in anoxic conditions • Low in toxicity • Environmentally non-hazardou s • Safe to handle • Easy to apply

Suitable for use on many types of eutrophied water bodies: •

STP lagoons

Lakes, ponds and water reservoirs

Golf course water features

Farm dams

Recreational water courses

Inactivation ofwaterborne emerging pathogem by selected disinfectants. AwwaRF Report 90886, American Water Works Association, Denver, CO, USA. Keil C., Forchert A., Fasrner J., Szewzyk U., Rorard W., Chorus I. and Kracke R. (2002) Toxicity and microcysrin content of extracts

refereed paper

water

FEBR\,JARY 2006 69


education

USING EDUCATION TO YOUR ADVANTAGE G Collier, C Cheeseman Abstract Changing the behaviour of rhe community is a crucial element of the work of chose employed in water authorities, councils, catchment management authorities and government agencies. This paper provides a brief guide for engineers, scientists and others working in the water industry about the hows, whys and wherefores of education. Unlike engineering, education is an inexact science; a mixture of science and arr, mastery, magic and fun. Like engineering, however, there are specialist skills in the design, delivery and evaluation of education that are well understood by those specialists who engage in education. In general they are poorly understood by those who specialise in other areas and dabble with using education. Following the tips in this paper will assist you to engage your community more effectively in education about water-related behaviour.

Introduction The use of education is in a unique situation in the water industry. On the one hand, education is often seen as the panacea for gaining community engagement to improve water quality or to reduce demand and/ or even get people to pay their bills. The common rhetoric is "we need to educate the community", whenever there is a significant change or crisis. Even when the status quo is being maintained, there are continual calls for educating people more effectively. On rhe other hand, education is often nor evaluated or used strategically by the range of water agencies. There is limited p rofessional development for those who plan and deliver education about water, or fo r those who might do so. There is often less opportunity for training chose professional staff who use education as a tool bur are nor education specialists.

Education can: • Increase knowledge (and awareness), • Improve skills, T his paper is loosely based on a presentation given by Grahame Collier at the NSW AWA Heads of Water Conference August, 2004.

70 FEBRUARY 2006

water

• Challenge attitudes and feelings and promote responsible values. Schools programs are often conducted, bur there are few programs targeti ng adults at home or during recreation. For people at work, there are even less education programs focus ing o n operational change in the factory or the office. Even in the current "water crisis" across the country there are relatively few righ tly targeted and evaluated education programs being conducted.

Tips on engaging your community more effectively.

• Conversely people lack skills in running education programs char influence behaviour and there is limited professio nal developmen t available. "I'd like to use

education more but we don't have an education officer to do it and I don't really understand how it works. "

What Might You Want to Use Education For? Of course this depends on your business or your specific project. In general terms, when you engage your audience (customer) you might wan t them to do some or all of the following: • Buy your product or service. • Seek your input, opinion and/or advice.

Why is Education Under-Used?

• Change their behaviour, e.g. to reduce water use or pollute water less.

Why is chis so? Ir is nor possible to answer chis question with p recision; however some indicators of the answer are:

• Enhance the credibility (marketing capacity) of your company.

• There is a limited understanding of and evidence for the effect of educatio n on behaviour. "Don't I just have to tell them

what to do; give them the facts and they will just do it?" • People across the water industry are understandably technically focused and fail to appreciate how education of their communities might assist their cause. "I

don't know how to add an education component to my project. " • Limited funds are provided to deliver education programs and often specialist expertise is not employed in its design or evaluation. "If only I could get a specialist

educator to do this. " • For too many people education is what happens in schools. This is not accurate, because learning happens throughout life. Ir is not appropriate when we are facing a water crisis now and we need to change the behaviour of rhe adults in our community who are impacting on water now. "OK, we

don't just need a school's project but how do I educate people in the community?" • The expectation that education is simple and anyone can do it. "Even though I cross

the bridge every day, I am not an engineer. Similarly, just because we all went to school that does not mean that we understand all about education".

• Pay their bill. The first issue fo r you is to be clear about what you are trying to do. It may be that you want to achieve more than one objective. If char is the case identify chem and rank them in order of priority. In essence, the answer to the question, "What do you want to use education for?" identifies rhe problem or issue you are trying to address. Good education planning always scares at chis point. The first tip is to know what you are trying to engage them about. What is the problem you are trying to solve; what is the problem behaviour?

Who Are Your Audience? In order to use education efficiently and effectively it is essential chat you define your target audience as precisely as possible. This involves going beyond a mere demographic profile. Certainly it is important to know and understand the age, gender, education level, socio-economic profile, ere of your audience. Bur you also need to be aware of a lot of other information, for example: • How they learn? • Where they currently receive education messages from? • Do they read pamphlets, newspapers ere?


education Table 1. Motivators for Behaviour Change Passian

Table 2. Motivators Available for Community Engagement Engagement By.... Example....

Comment

Crisis or Event

• • • • •

The oi l spill in Sydney Harbour The Pooh Marches The drought Falling dam levels Water restrictions

Crises hurt and it's hard to manufacture them. When crises occur it is important to use them to promote more responsible progra ms. However in most circumstonces it i s not appropriate to base the w hole education prog ram on them; because when the crisis posses so will the program.

Hip pocket

• • • •

Paying what it really costs User pays Incentives, rebates and subsidies Financial Rewords

Hip pockets and political/ organisational credibility ore always intertwined. If the community is being asked to pay m ore then related education is required to explain why and to seek community support.

Knowledge

• Information provision • Appealing to a rational, common-sense response • Just explain and they will do ...

While knowledge is on important i ssue too much informa tion con be counter productive; Some people know lots but " don' t a lways do" OR "don' t always do what they kn ow."

Attitudes and feel ings

• Passion • Concern for future generations • M otivation and visible activity

"Passion" works for some people some of the time. Early adopters and champions often are motivated by passion. But it is not necessarily a useful tool for others because sometimes it gets in the way and puts people off.

Location

• Proximity to water is a motivator • Recreational use of water • Need for water to support livelihood

While there is substantial research to support the proximity to water theory it is n ot a perfect motivator. Not everyone is "located " near water and of those that ore, not al l are engaged in reducing water pollution or reducing demand .

Regulation

• Penalties and offences

These do have a deterrent affect o n behaviour when they are visible and appropriately enforced. They establish a benchmark for what the community is prepared to acce pt. BUT just having a law on the statutes witho ut enforcement is useless.

Demonstration Crisis Knowledge Regulation, laws and fines Kids (future generations) Proxim ity Cham pions Dollars Location

• Who are the champions with in their commu nity; will they listen to these people? • Are there ocher programs or social norms o n which char you can build your program • What are the barriers to people changing their current behaviour and raking up a mo re d esirable behavio ur? I n designing any education program ir is important to tal k with stakehold ers in o rder to defin e you r aud ience closely. There are people our there who know things about your audience char you need to know. Find chem and talk with chem. Pick their brains about whom it is you are crying to educate and how you reach them.

The second tip is to know your audience.

What Drives People's Behaviour? The specific outcome of most ed ucation programs is rhe drive towards behaviou r sh ift. Getting people to d o something d ifferently and to rein force appropriate behaviou r is rhe ul timate goal. People's behaviou r is affected by a range of mo tivators. These are highlighted in T able 1. Of these, a num ber are specifically related to the educatio n process, e.g. growing knowledge, building on passio n, using champions, demonstrating responsible behavio ur. Bur ir n eeds to be acknowledged that other drivers of behaviour exist and can be used by policy and program providers. While there is no direct, consistent linear relationship between improving any of these and gaining appropriate behaviour

outcomes, all are precurso rs co behaviour change in different ways with different people. To promote behavio ur-shift, ed ucation should be used in close conjunction wi th ocher tools.

The third tip is we have lots of motivators for engagement going for us. We would be best to use whatever behaviour possible to drive people's behaviour. Table 2 p rovid es some derail about the use of some of th ese motivators to engage rhe community.

How Do You Identify the Barriers to the Behaviour You Wish to Encourage? Ir is important to identify rhe barriers char may inh ibi t your audience. The more

info rmation you are able to obtai n, the greater chance yo u have fo r success in meeting your objectives. There has been research carried our in Australia and overseas relati ng ro the barriers for a variety of behaviours, so initially a literatu re review should be conducted. Following this, qualitative research th rough focus groups and observation al swdies may be carried out to scope the deeper arri wdes and b e haviours of your target audience. If you rhen wish to en hance rhe knowledge o f barriers in the community furth er, rel iable information may b e obtained by undertaking su rveys of the proposed audience. So char you can see the point of this step, some examples of the barriers char you migh t identify through chis process are

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water

FEBRUARY 2006 71


education listed below. Nore rhar chis list is illustrative only and is nor exhaustive. • The audience may have a low level reading ability; therefore to distribute a brochure requiring a high reading age would be a waste of t ime. • The audience might nor be able to attend evening events if child care is not provided; therefore run events at other times and/or provide child care. • The audience do not read English well; therefore print material needs to be low literacy or translated into community languages. • The audience do nor place a high priority on acting on your particular water issue therefore you have to raise their interest in the issue. • The audience accept the need and the issue bur don't know what to do about it; therefore education needs to be directed at providing realistic, alternative behaviours and not to waste rime on explaining the need.

The fourth tip is to identify the harriers to the behaviour you wish to encourage and to ensure your program is designed in such a way as to avoid or deal directly with these barriers.

Education: Goals, Objectives and Outcomes To conduct effective education programs you have to know what you are intending to do and what you are intending to achieve by doing ic. Like every area of human endeavour, education is full of jargon. What you are intending to do is a goal and this can be broken down into objectives that when ful filled will mean that rhe goal is achieved. What you have achieved at the end of a program are the

outcomes. Therefore an education program that you might conduct might be shaped as o utlined in the following example:

Goal: By 2007 all residents in the ....... will reduce water use by 20 %.

of the people in ... have installed dual flu sh toilets in their houses. This means that X% of people have d ual flu sh toilers. Goals, objectives and outcomes always relate to the knowledge, skills and/ or attitudes that you wan t to achieve through the program. They do nor relate to the methods of how you are going to achieve these things. For example many people think char "distribu ting 2000 brochures" is a program objective. WRONG! Ir is a method of rhe program; it indicates how we are goi ng to deliver o ur program. The obj ective is what reading the brochure is going to help people to know, to believe or to do.

The fifth tip is that all projects must clearly state goals and objectives. Outcomes should be identified and measured (see below).

Evaluating Our Education Efforts Education efforts are always under scrutiny. Do they work? Are they value for money? Surely it would be easier just to pass a new law or establish a regulatio n? Two important responses are desirable to these important questions. The first is that education must support o ther efforts. Just having a dual flu sh toilet available will do nothi ng to reduce water demand. People have to know it's available; they have to see that the advantages outweigh th e extra co sts; they have to know how to install ir ere. This involves rhe effective integration of education efforrs. Second, education programs must always be evaluated. All objecrives should be measu red. To what extent were they achieved) What were the outcomes of rhe program? Evaluation can be defined as the process (collection of judgments/measures/ observations) about how the program operates and rhe effect it is havi ng. This must be as objective as possible and data on which the judgments are based should be collected from as wide a range of sources as possible.

education program residents will:

Space does nor allow fo r a derailed outline of how to undertake evaluation however, the NSW EPA (2004) document, Does Your

• Increase the use of AAA rared showers by 20%.

Program Make a Difference: A Guide to Evaluating Education Projects and Programs

• Install dual flush toilers in 100% of new houses.

is a very useful guide to how to evaluate effectively.

• Retrofit installation of dual flu sh toilets in 10% of existing premises.

The sixth tip is that all programs should be evaluated in order to determine whether its objectives were met and what outcomes were achieved.

Objectives: As a result of the water

• Reduce garden water use by 20%.

Outcomes These will measure the extent to which rhe objectives have been met. They are stated as outcomes of the program. For example 7%

72 FEBRUARY 2006

water

Education and Trust If you are going to attempt education that changes behaviour about water, which most

people rake for granted, then they have to trust you as a credible source of in formation and education. Water authorities who are trusted sources of water are also trusted sources of information about its use and quality. Becoming a credible educatio n source also assists the water authority to further its broader image. In order to achieve this reputation some current or potential water education p roviders are: • Working h ard on creati ng an image that is acceptable to their audience. • Working in partnership with other agencies in order to conduct joint education programs. • Poolin g resources and expertise so as to use joint educative efforrs. • Engaging experts to assist rhem to run (and/or evaluate) effective education programs.

The seventh tip is that you have to be a credible education provider to your audience in order to gain their trust.

Researching and Piloting your Education Program Research is an important component of any education p rogram. Ir can assist in rhe design and delivery o f the program and also allow you to gain a better understanding of your target audience's attitudes. Educators (th ose who deliver education) are happy to share their experiences and even the co ntent of their p rograms. So why reinvent the wheel? An important component, particularly for wide reaching education programs, is a pilot program. By piloting rhe program, to a limited but representative audience, important improvements can be made. To find that your full program contains some major limitations is far more costly in the long run.

In relation to responsible water use, the following summary data is drawn from rhe NSW W ho cares about rhe environment study (2003) and the most recent ABS data (2004) . • 57% rare water as the most important environmental issue. This compares to air (37%) and flora and fauna protection (2 1%). • 17% rank water issues as the highest priority for the NSW Government; compare 12% fo r education and 10% for air quality. More than 90 % of Australians reported conserving water in the garden, usually by mulching (59%) . More are using recycled water on rhe garden (18% in 2004 versus 11 % in 2001 ), planting natives (17% from


education I 0%) or not watering at all ( I 0% up from

6%). Water conserving devices were used in 82% households in 2004, principally with d ual flush toilets (74%) .

The eighth tip is to take a look at what is already out there and if possible pilot your program before rolling out to a wider audience.

Planning Your Education Activity Just like the construction of a sewer or a house, education must be planned in a detailed and comprehen sive m anner. Effective education does not just happen . An immense amou nt of hard wo rk goes into its planning. While there is no blue print, every program sh ould have a tangible plan of what it is intending to do with whom and how ic is intending to d o ir and evaluate it. The E PA (1 997) booklet What we need is a community education project is a useful guid e to all those who are developing programs. l e will provide you wich a step by step guide about planning your program. J ust letting ed ucation 'happen ', and building on it opportunistically when it does, is not good enough. Maybe it is even co unter productive because when it fails to meet ics objectives, you don 't get funding for another attempt.

scientists) can use education more effectively if they follow the brief h in ts in this paper.

About the Authors

Bibliography The fo llowing references are important reading for those involved in d elivering and evaluating education. Environment Protection Authority ( 1997).

What we need is a community education project. (Sydney) Environment Protection Authority (2004). Does

Your Program Make a Difference: A Guide to Evaluating Education Projects and Programs. Fien, J. and Tilbury, D . (2002) The Global Challenge ofSustainability. Funnell S. ( 1997): Program Logic: An Adaptable Tool for Designing and Evaluating Programs in Evaluation News and Comment, Vol 6, number 1, July 1997, Ausrralasian Evaluation Society, ACT McKenzie-Moh r D, Smith W. ( 1999) Fostering

Sustainable Behaviour: An Introduction to Community-Based Social Marketing. New Society Publishers. Canada Robinson L., G lanznig A. Enabling Action (2003): A Handbook far Anyone Working with the Public on Conservation. H umane Society International. Sydney

The final tip is that you have to plan and work at it.

Strategic, qualiry education programs set themselves apart from the rest because they are research-based: they are programs built on kn owledge. They identify the problem chat is to be add ressed and they in tervene in the most appropriate ways to address that p roblem with the audience; they promote change. For example, in NSW over the past six years ed ucacion has been used in relationship to stormwacer qualiry. Although there is still more to achieve people are washing their cars less and from buckets, they are wash ing out their paint b rushes on the grass, cleaning up dog poo, b inn ing their cigarette butts m ore, and not disposing of green waste in creeks, drains and rivers. These were all id entified as p roblem behaviours when che p rogram was first planned.

All water authorities have a responsibiliry to use educatio n as much as possible and as effectively as possible. AJI non-education specialists in the water sector (engineers and

Grahame Collier is the Directo r of T Issues Consultancy, a private co mpany specialising in education and training. He was previously the D irector of Industry and Comm uni ry Ed ucation at the NSW Environm ent Protection Auchoriry. He is currently the President of rhe A u stralian Association of Environmental Education. Corinne Cheeseman is the Education Manager at the Australian Water Association. H er role is to support water educators nationally th rough the Water Education Network. Corinne is responsible for all of AWA's education related activities and projects. She previously worked ac Sydney Water in various roles re lated to water quality, water co nservation and community and school education. For assistance in educatio n planning and evaluation contact Grahame Co llier ac tissues@acay.com.au or Corinn e Cheesem an at ccheeseman@awa.asn.au.

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Conclusion

Good education programs are a mixture of science and art, mastery, magic and fun. This is nor to suggest chat hunches, intuition and professional judgments don't play a part. In fact, they are vital ar the right time and used in the righ t way.

Wadsworth Yoland (I 997). Everyday Evaluation on the Run. Allen and Unwin. S t Leonards, Australia.

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Water Business aims co keep readers alert co business news and new product releases within the water sector. Media releases sho uld be emailed co Brian Rault at brian.rault@halledir.com.au or Tel (03) 8534 5014. AWA wish to advise readers chat Water Business information is supplied by third parries and as such, AWA are not responsible fo r the accuracy, or otherwise, of the information submitted. both power and water usage. "Our staff are being trained co actively seek opportunities to increase efficiencies and as a result we now have 200 pairs of eyes managing the company's day-co-day operations in line with EMS standards." "A closed-loop water cooling system, which we use co cool our d ies, is currently being investigated. The cooling system is a

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Water Journal February 2006  

Water Journal February 2006