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Volume 2 8 No 8 December 2001 Journal of t he Australian Water Association

Editorial Board F R Bishop, Chairm an B N Anderson, R Considine, W J Dulfer, G Finke, G Finlayson, G A Holder, B Labza, M Muntisov, P Nadebaum,J D Parker,] Rissman, F Roddick, G Ryan, S Gray

CONTENTS

Ch; Water

is a refereed journal. This symbol indicates chat a paper has been refereed.

2

FROM THE FEDERAL PRESIDENT: ANew Model for Operating our Association

Submissions

4

FROM THE EXECUTIVE DIRECTOR: No Magic Bullets

Submissions should be made co E A (Bob) Swinton, Technical Editor (see below for details).

4

FROM THE TECHNICAL DIRECTOR: Where is the Logic?

P e ter Stirling

6

INTERNATIONAL AFFILIATES: ASingle Strategic Council

Technical Editor

7

MY POINT OF VIEW:

Managing Editor

E A (Bob) Swinton

Is the Water Industry Truly Sustainable? Trevor Brid le

4 Pleasant View C res, Wheelers Hill Vic 3150 Tel/Fax (03) 9560 4752 Email: bswinton@bigpond.nec.au

8

CONFERENCE REPORTS

Crosscurrent Editor

15

CROSSCURRENT: Water News Around the Nation

24

INTERVIEW: Peter Moore and Keith Codee

W (Bill) R ees PO Box 388, Artarmon, NSW 1570 Tel +61 2 9413 1288 Fax: (02) 9413 1047 Email: brees@awa.asn.au

Water Production Hallmark Editions PO Box 84, Hampton, Vic 3188 Level I, 99 Bay Street, Brighton, Vic 3186 Tel (03) 9530 8900 Fax (03) 9530 8911 Email: hall111ark@halledit.com.au

FEATURES: ALLIANCE CONTRACTING For fast-tracking of innovative projects, alliance contracting has advantages. Three projects are reported. 26

Graphic design: Mitzi Mann

D McGill

Water Advertising N ational Sales Manager: Brian R ault Tel (03) 9530 8900 Fax (03) 9530 8911 M o bile 0411 354 050 Email: braulc@halledit .com.au

32 52 WATER

58

APPLICATION IN THE SYDNEY DRINKING WATER CATCHMENTS

AWA

Executive Director

~ AUSTRALASIAN STANDARDS FOR ON-SITE SEWAGE MANAGEMENT: K Charles, N Ash bolt, D Roser, D Deere, R McGuin ess

PO Box 388, Artarmon, NSW 1570 Tel +6129413 1288 Fax: (02) 9413 1047 Email: info@awa.asn.au ABN 78 096 035 773

C hris D avis

MELBOURNE'S WESTERN TREATMENT PLANT AUGMENTATION T Schubach

Australian Water Association

Ba rry N o rman

ALLIANCE BRINGS INNOVATION: WOODMAN POINT WWTP K Bartley

Water (ISSN 0310 â&#x20AC;¢ 0367) is published eight times a year in the months of February, M arch, May, June, August, September, November and December.

Federal President

THE STIRLING ALLIANCE: A CASE STUDY

~

AUSTRALIAN WATER ASSOCIATION

Australian Water Association (A WA) assumes no responsibility for opinions or statemen ts of facts expressed by comribut0rs or advertisers. Editorials do not necessarily represent official AWA policy. Advertisements are included as an infonnation service to readers and are reviewed before publication tO ensure relevance to the water environment and objectives of AW A. All material in Water is copyright and should not be reproduced wholly or in pare without the written permission of the General Editor.

Are the new standards adequate?

BUSINESS 65

Report by Bob (EA) Swinton

67

MEMBERSHIP

68

MEETINGS

SPECIAL WATERWORKS EDITION 40

Water is sent to all AWA members eight times a year. It is also available via subscription.

BALANCING THE WASTEWATER EQUATION G

44

Wall

UPGRADING THE MORWELL SEWAGE TREATMENT PLANT MCook

47

Subscriptions

TRAINING FOR OPERATIONAL STAFF: THE NATIONAL WATER INDUSTRY TRAINING PACKAGE 2000

PRACTICAL EXPERIENCES WITH PARTICLE COUNTERS M Colwell

* Part 2 of the article by W Paul and N T Diamond, Designing a Monitoring Program for Environmental Regulation, w ill be p ublished in the next edition of Water Journal.

Visit the Australian Wat Assoc ation

HOME PAGE

and access news, calendars, bookshop and over 100 pages of Information at

OUR COVER: The Woodman Point Wastewater Treatment Plant incorporates some novel features, in particular the circular SBR. This issue features this project along with two others which have been built utilising the Alliance Contract system. Photo courtesy of The Water Corporation.


FROM

THE

PRESIDENT

A NEW MODEL FOR OPERATING OUR ASSOCIATION Although I have been an AWA member for a long time, my active involvement is probably a lot more recent than for many of my colleagues in leadershjp roles around the country. Perhaps as a result of that, or because I am a bit of an independent at heart, l have a slightly different perspective. AWA's history, over almost 40 years, began ve1y n1.uch at grass roots leve l, as bra n ch es w e re gradually established, building up to eight. In the early years, bra n c h es w ere strongly autonomous and the then Federal Council, which met twice a year, was a bit of a toothless tiger, derided by locals for its lack of contact and its general irrelevance. In the era of Peter Hughes, our first Executive D irector, and Margaret Bates, whom Peter engaged to smarten up the national operation, things began to change. Federal Barry Norman Office, as it became known, started producing the A WWA Handbook, which has now become the authoritative Australian f;f/ater Directory. In 1992, the first O z water exhibition was organised in Sydney, providing a much better shop window on the industry and, of course, ea rning useful funds. At the same time as the 'dreaded Feds' became more effective and more strategic, the rapidly changing face of work in Australia began to deprive our Association (along w ith most others) of their accustomed workforce of volunteers. No longer could a water authority set aside an individual, or a team, to manage an event for the Association. C ash was tighter too, so the sponsorship equation cha nged fro m one of patronage to one o f more hard-edged promotion. We have now arrived at a point where branches, still playing the key local role for members, are relying more on paid support and our national operation has grov111. and is performing many of the functions centrally that used to be delivered by branches. This has led to some culture-shock, as roles change, so the next important step forward is to begin to deploy all our resources effectively to reach our objectives. T he nlission statement fo r AWA is, the Board recently agreed, to p ron-rote sustainable management of water, below which sits a basket of activities, including services to members and information, advocacy, liaison, training and so on. To deliver on our objectives, we need a seamless operation, in which Bra nches and our national operation work hand- in-glove. I' m convinced we have to instill a new sense of shared responsibility and shared ownership of projects and resu lts. There 1s no excuse fo r members' resources to be 2

WATER DECEMBER 2 001

expended on duplication of effort, nor on differen t directions. The o ld cu lture o f parochialism and a tendency towards a 'silo' mentality has to be replaced. This is where my different view comes into play. I think we also need to rethink our financial operations. Times are hard commercially, in the water business and for AW A. O ur financial result last year was a significant deficit, which did not threaten our viability at all, but which must not be re peated. Our financial manage m en t ha s t o be excellent to keep on top of the fl uid situation, and one option could be to consider consolidating fina ncial operations in a mann er that . would allow greater support of activities across the whole Association and importantly a consistent level of service to all M embers - ie Telstra 's level of service J ust as my own business operates many branch offices, but uses a central account, perhaps AW A should consider a sinlilar approach , even if that's not achieved in one go. It would allow greater support to the smaller Branches such as ACT, NT and Tasmania and afford them the opportunity to engage the extra resources essential to improving the local services to members. Taking a step like that requires complete confidence on the part of everyone concerned. Members of the Board and Branch Presidents are now canvassing the views of Branch Comnlittees on this, and l encourage eve1yone to talk the issue over. AW A needs to be strong to stay ahead and remain relevant in today's increasingly competitive environment. I hope we can gradually move in th e direction of more efficient use of our overall resources and ideally a consolidated fi nancial operation, so we can focus our attention on our goals. Communication is th e key that will unlock AW A's real potential - ongoing, constructive, open commun ication between our national Board, our staff in Artarmon and our Branches, both volunteers and staff. Eliminating tensions over money is one thing, but elinlinating misunderstanding and gaps in information is another and I venture to suggest that it's probably the more important, in the long ru n. With Internet technology today, there's no excuse for not having excellent lines of communication going, pe1111anently. That, coupled with gen uine, ongoing commitments from national and branch players to keep in touch and in tune, is going to make AW A fly. Barry Norman

Aquaphemera Water, in any form, had scant reference in any of the policy statements issued by the two major parties during the recent federal election. This leads me to wonder if the industry could improve its role as a lobbyist? My prime interest is in the field of rura l and urb an flood ing. Flooding, and most other aspects of water resources, is primarily a State responsibility and the most active lobby group is that of the Floodplain Ma nagement Authorities of New South Wales. Members are mainly drawn from elected and professio nal staff of local governments throughout the State and run an a nnu al Conference, with field visits to discuss the local flood problem. As a result the m embers are extremely well-informed in all aspects of flood mitigation. T h is is i n co nt ras t to Queensland w hich has a similar number of buildings at risk b ut lacks any co- orientated State policy on floo d risk. Interestingly, the FMA of NSW circulated all members w ith a summary of the election flood p olicy of the two m ajor federal parties. D uring its pe1iod in office the Coalitio n reduced federal government assistance fo r floodplain m anagement to w hat is probably the lowest level in the last thirty years. It also essentially restricted federal fu nding to regional Australia and changed t h e fund ing con tributions from 2:2:1, fo r fe dera l , state a n d l o ca l government contribu tions, to 1:1 :1. The Labor election statement indicated that they would to revert to 2 :2 : 1 funding and increase the overall fede ral contribution. T he details of the differences in policy are not the issue here, b ut the circulation of the outlines of the two policies prior to the election by the FMA is an illustration of how other aspects of the industry could lobby fo r more recognition at the time of a Federal (or state) election. A flood prior to the election would have been a majo r po licy and purs e opener! Dingle Smith


INTERVIEW

we agreed with the contractor. The incentive in this case is to bring the project in under budget in which case there is a sharing of the cost savings.

Rod: Keith, being a new process are you confident th at the plant will achieve your opera ting objectives? Perhaps you might also outline the wrrent progress of the plant and whether there has been innovation and cost savings achieved with the EPC approach? Keith: Water Corporation made th e decisi on to construct the M IEX plant after extensive pilot plant work over several years. We are reasonably confident of success, but as with any first of its kind proj ect such as this, we will all breathe a lot easier when the final commissioning is fi nished in D ecember. T he EP C approach has achieved many innovations in areas such as smaller concentrators due to higher resin concentrati ons and improvements to th e regen eration process, all the way through to m e tho ds of constructing various aspects of the plant in ways that we have not seen before in more traditional approaches. This particular proj ect was also n o ta ble i n the w ay that th e co nstru cti o n cost w as drive n down

~ Bowdens ., ~

GROUP

between the initial estimate and the final targe t cost through a highly interactive process between the Water Corpo ration and the E PC contractor to refine the scope.

Rod: Establishment of the Proj ect Target Price (PTC) is always a debatable issue? H ow has this been handled at Woodman Point and with the MIEX plant? Peter: At W oodman Point for example the PTC w as determin ed after about three months preliminary design work and detailed costing by the alliance team w hich w as then indep endently audited . For the M IEX plant the predesign work for the plant upgrading was carried out by Black & Veatch . This was then p riced and then independently audited. The final agreed price then became the ' Fixed Price'. The PTC and fixed costs are compared with our original defi nition estimates. History indicates the accuracy and confidence in these estimates has been and remains an issue particularly for the utilities . W e have reviewed our esti mating processes and developed a detailed in house system to improve our o w n es timating. In addition, we are co ntinu ing to look at m ethods of

ensuring appropriate PPT C figures are achieved as we continue to be innovate with relationship contracting. W hat is witho ut question is that we have achieved significan tly more innovation in th e delivery of our new assets throu gh relatio nship contracting. W e continu e to be open to further opportunities that will enable breakthroughs to be achieved in the definitio n, design and constructio n phases of projects.

Rod: What are your main problems in achieving proj ect delivery? Peter: W e have been very successful in achieving o ur proj ect delivery on time and to budget. O ver the last four or five ye a r s we h ave c omp l e t e d our programmed works at a cost which is within a few percent of the targeted, including last years $500 million capi tal works budget. Our main problems relate to delays with environmental, aboriginal heritage, native title and land acquisition. We are now looking at bringing these activities forward so that they are carried out at the planning phase rather than the proj ec t defin ition phase.

Thank you Peter and thank you Keith.

WATER SERVICING COORDINATORS

Bowdens would like to congratulate their team on Bowdens' appointment as Water Servicing Coordinators for Sydney Water. NEW STREAMLINED PROCESS FOR DEALING WITH SYDNEY WATER Obtaining a Sydney Water Section 73 Certificate is now a whole lot easier. Instead of lining up at Sydney Water, applications will now be lodged with Bowdens Group, a licenced Water Servicing Coordinator. Based in Parramatta, Bowdens Group is able to service the entire Sydney Water area. Greg Gearin, Managing Director of Bowdens Group, welcomes the new s treamlined process . "This is a positi ve move by Sydney Water that will revolu tionise the industry," he says, "Bowdens will be able to lodge

applications electronicall y with Sydney Water and keep track of their status online - a real time-sa ver for developers." Anyone planning a development or subdivision, which requires council consent, may need a Section 73 Certificate. "Bowdens Group will coordinate the entire process on their behalf, so developers won 't need to tear their hair out over it like they have in the past," Mr Gearin said. " Adding to the range of existing development services offered by the Bowdens Group, we will coordinate Section 73 Certificates, feasibility studies, Notice of Requirements,

design of sewer and water, project management , construction and handover." "Feasibility studies are now simple," says Jennifer Spencer of Bowdens Water, "We can directly access Hydra (Sydney Waters database), upload subdivision and design plans automatically and retrieve Sydney Water information fast." The new process for dealing with Sydney Water is just a part of the full suite of services offered by Bowdens Group - for more details go to www.bowdens. net.au or call Jennifer Spencer on (02) 9633 2277 or 0413 443 407.

For your next Section 73 Certificate, and details on how we will benefit you and your Project, contact: Bowdens Group - "the outcome managers" - www.bowdens.net.au Jennifer Spencer - 02 9633 2277 0413 443 407 DEVELOPMENT CONSULTANT WATER DECEMBER 2001

25


PROJECT

IMPLEMENTATION

THE STIRLING ALLIANCE A CASE STUDY

-

D McGill Abstract The Stirling Alliance was responsible for constructing 20 km of1420mm steel pipe and 7km of road near the town of Harvey, 140 km south of Perth. The project was delivered within budget and on tim e. It received In stitution of Engineering awa rds, both State and National, in the ca t egorie s of Management of Engineering and of the Environment. In addition it won the Nati onal Case Earth Awards for the Causeway construction. over $10 million category and the overall Best Project Award. The project delivery would be in the form of Department of Environmental Protection a number of separate schedule of rates and the Environmental P ro t ection construction contracts. Auth ority commended the Stirling Alliance for its performance, as did the b) The second part involved 20 km of client, the Water Corporation. pipeline from Stirling Dam to H arvey, with associated outlet structures, and 7 km This paper outlines the planning, of n ew road, incorporating four development and execution of the Stirling causeways. T he firs t 7 km of pipe was Alliance project and in particular the through an environmentall y sensi tive Alliance contract processes adopted to 1iver valley where the maximum allowable complete the project successfully. clearance widths were 13 metres and in Project Description so me stretc hes only 9 metres. The remaind er was through hilly, rocky P erth's population is expected to country. Due to the potential impact on increase fro m 1.2 million to 1. 7 million endangered flora and fauna, the EPA by 2010. T o meet the demand fo r required a Public E nvironmental R eview potable water, the Water Corporation covering all the work including the commenced work on the Stirling-H arvey construction of the new Harvey D am, and Redevelopment Scheme. T he Stirling some landholders had expressed concerns Dam 15 km south of Harvey supplies water to the downstream Harvey W eir to Why an Alliance? meet the irrigation demands in Harvey. The project tea m wanted a form of T he Water Corporation is now in the project delivery fo r the seco nd part process of constructing a new dam to which would minimise the impact of risk, replace the existing Harvey W eir. The dam was identified as a major source of be within time and budget and avoid disputes. Data was collected on alliances potable water to supplement Perth's water supply requirements. In 1999, a around the world and a suitability matrix 1420 mm diameter steel pipeline was was developed to measure each of the criteri a. Upon establishin g weighted design ed to transfe r up to 200 ML/day a scores for each of the project criteria, it distance of 106 km from Stirling Dam to became apparent an alliance was the most T amworth R eservoir near R ockingham. suitable form of project delivery for this The project was divided into two project. differen t sections of work, with different The key determinates for the selection forms of project delivery. were : a) The 86 km of pipeline from H arvey to 1. Complexity of the construction project, T amworth Reservoir presented no major especially the pipeline construction in the construction issues as the terrain was £lat river valley. and the soils were predominantly clay or sa nd. The soc ial, environmental or 2. The e nvironmen tal c onst rai nts abori gina l issu es had been previously associated with the Public Environmental addressed. As a result it was decided the Review. 26

WATER DECEMBER 2001

3. The tight time frame. W ork cou ld o nl y be completed b etween November and April due to the wi nter ra ins effecting construction in the clay soils. Construction could not start un til the Mi niste r fo r the Enviro nm ent signed off the Public Environmental R eview. 4. T he interfaces of pipeline and road construction. 5. The social issues with landowners and stakeholde rs 6. The fast track nature of the entire project mean t potential redefinition during the construction period 7. T he potential fo r disputes in a lump sum contract 8. The risk imposed upon a sole contractor was considered too great 9. The project estimate ($32 milJion) was large enough co warrant an Alliance contract.

Selection Process Previously, the project team had put o ut an expression of interest fo r contractors to prequalify to co nstruct portions of the 106 km of DN 1400 p ipeline and 7 km of road. Submissions were then requested from these same applicants to become a partner form ing the Alliance with the W ater Corporation. Eighteen subm issions were received and four preferred applicants were chosen based on the selection criteria developed. T his number was reduced to two after four, half-day workshops. Following this there were two, two-day workshops to ide ntify th e final p referred Alliance partner. In this process, there were key requirements identified for a successful alliance: • Commitment to the culture of an All iance • Expertise to complete the construction • Personnel to work well togethe r • Trust and respect for each other • Commitment to project objectives • Encouragement of innovation Once the preferred Alliance partner was chosen, the next step was co agree on a fai r risk-reward stru cture and develop the Project Target Cost (PCT). The riskreward workshop was also the fo rum to


PROJECT

Pipe laying in a narrow corridor.

ascertain th e basis of the Alliance agreement. At th is tim e the percentage for overhe ad and profit was also agreed betwee n the proj ect team and the Alliance Partners . Th e scope of work for the pipeline and road had been previously fina lised for tender as lump sum contracts so that design and doc umentation was compl ete. The Proj ect Target Cost was to be established as a direct cost, without allowance for profit and overhead. In ord er to inc rease the ince ntive for the Alliance to redu ce the Projec t Target Cost, consideration was given to in creasing the percentage reward

IMPLEMENTATION

for the Alliance partners as any underrun increases. Any overrun. would be shared by the project participants in an agreed manner. There can be a limit or cap placed on the amount the Alliance Partn ers wou ld be liable to pay. In the case of an underrun , an incentive was also incl uded in the form of three soft key performan ce indicators. These key areas were identified as environment, sa fety and pu blic relations. The agreed percentage of the underrun paid to the Alliance Partne rs was adjusted accord ing to how the Alliance Board assessed th e performance of the Alliance in those three key areas.

Management Personnel Selection Following agreement of the risk- reward process, the Allian ce Partners were then appointed. In alliance terms the alliance partn ers are referred to as the OAP (Other Alliance Partners) . The successfu l applicant was a joint venture between OM Civil (p ipclayers) and Brierty C ontractors (road constru ction). Both these companies are medium sized W estern Australian civil co ntractors .

The Stirling Alliance Board , the key decision making authority, comprised one senior manager each from the Water Co rporation , OM C ivil and Bri erty Contractors. The Lead T eam, led by the Alliance M anager, managed th e project and implemented decisions made by th e Allian ce Board. The structure and composition of both th e Alliance Board and the Lead T eam was critical to the success of the project. A fla t reporting structure was adopted fo r the lead team, w hich prevented duplication of effo rt. The philosophy was to selec t personnel from each organisation on a "best for the job" basis. The Allian ce Manage r, Environment Manager, Quality Representatives and D esign Managers were from the Water Corporation as e mployees or consultants. The Safety Manager, Pipe Proj ect Manager and Pipe Construction Manager w ere from DM Civil. The Roads Project M anager, Roads Constructio n Manager, Publi c Relations Office r and Safety Manager were fro m Brierty Co ntractors. At th is time Sl"lD Consulting was n omi nated as the fa cilitato r. SR O Co nsulting was responsible fo r managin g

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PROJECT

all meetings for the Allian ce Board and Lead Team as well as meetings for innovations, inductions, closeo ut and many others. The role of the facilitator cannot be underestimated and the faciJjtator played a major part in developing the Alliance culture and fostering cohesion between the project participants. A key factor in the success of the Stirling Alliance was the involvement of top management from the OAP. DM C ivil has two principals of the company. One was an Alliance Board member and the other was the Pipe Project M anager. Similarly Brierty C ontractors has two principals. One was an Alliance Board member as well as Roads Construction Manager and th e other the Public R elations Officer. These fou r people had a lot of involvement in th e project from start to finish and the workforce responded well to this. As the top management had day-to-day contact with the proj ec t, th e decision- making processes for the Alliance Board and the Lead Team were very effective.

Project Target Cost Developme nt/Agreement T he development and agreement of the Project Target Cost was a key element in the Allian ce process. It is the measuring stick fo r financial performance of the Alliance. Also it is the point from w hich the risk or reward is assessed at project completion. However it also can influence the culture and performance of the overall Alliance, sho uld it be considered too low or too high. It is paramount that as much work as possible is put unto establishing the Project T arget Cost amount so that it is seen as fair and reasonable by all project participants including the client, so an audito r was appointed to provide an independent assessment. To assess the Project Target Cost accurately the earli er work carried out by the client becomes im portant. T he geotechnical studies have to be suffi cient enough to be able to price the Project T arget Cost with o ut tryin g to price too many un knowns. If this is done then the amount of rock and unsuitable material can be allowed for more acc urately in the Project Target Cost. Any constrain ts on the project from environ mental and aboriginal issues can be allowed for in th e computations. In o th er words a successful Project Target Cost development is dependent on accurate factual data and the scope of work being covered completely. By having the proj ect participants j o intly develop the Project Target Cost with an auditor involved, there were decided benefits for the proj ect. Apart 28

WATER DECEMBER 2001

IMPLEMENTATION

from scoping the project in a more defined way, it gives an opportunity for the k ey A lliance members to defin e the construction process in de tail. By having designers, contractors, environm e ntal perso nnel an d client representatives involved a lot of potential issues are resolved prior to start of construction. As an example the process for constructing the pipeline in the l;....;::3111.::;~~. river valley was developed w hich Pipe laying in a river valley. minimised the movement of excess material and backfill . As access was ipated in a co mprehensive workshops difficult and the logistics of moving spoil, w hi c h aim ed t o remove barriers, sand and large diameter pipes w as encourage communication and develop complex, the opportunity to sit down and the Alliance Charter and Policies for plan the work w ith all the key personnel enviro nment, public relations and safety. present was invaluable. A number of stretch targets fo r each area The Project Target Cost development were also developed , with the aim of is also a measure of the cohesion and setting performance targets over and above w hat would normally be achieved cul tu re of the Alliance team. As there are many difficulti es to overcome in terms of under a normal contract (Business As agreement of the process and costing fo r Usual). This was an important step in setting the ground rules and specific objecth e project, the way the team members work togeth er is an indicator how well tives for the project, w hich ul timately the alliance will work in the future. In the ensured that the entire Alliance workforce case of the Stirling Alliance, the members operated as one integrated team towards of the lead team were already becoming achieving th e same high perfo rmance ou t co m es. The re we re up to 170 a closely knit team, w hich could work personnel on site worki ng for the Stirling together in trying circumstances. The Alliance. Alliance culture was thus established simply by choosing the people who could The challenge was to have all the team work well together as a team. members committed to working for the Stirling Alliance rathe r than for their T he Agreement should be compl eted as soon as possible after th e risk-reward respective companies. T his was achieved process is agreed. In this manner the throughout the OAP and their various subcontractors, including welders, tra ffic docu ment can be signed by the project participants prior co commencement of control officers and d rilling and blasting personn el. Apart from the workshops the co nstruction. culture was quickly developed by estabAlliance Culture lishing a camp to house all the employees A key aim was to change the way of together. This engendered a sense of thinking of all Alliance team members to belonging to the Alliance rath er than the individual company that employed them. embrace the allian ce meth odology. In tradi tional lu mp sum type contracts there Throughout the project there were is o ften a "them and us' philosophy. T he remin de rs to all personnel of the need to client and the contractor ca n become maintain the Alliance culture in meetings adversarial leading to potential contractual and in the Alliance newsletters. The record problems and even disputes. In an alliance of personnel in terms of public relations the contract parties agree to: and the environment was excellent and the Alliance members were proud of these • Share risks and rewards fea ts. • N o variations o r late nt cond itio ns The workers also quickly recogn ised • No disputes the efficiencies gained by having th e • Share reso urces decision makers on-site full time. They • No blame culture were pleased to be free of th e shackles of • Self- regulation a hard dollar contract in terms of th e • C hange control mechanism for scope frustratio n of waiting fo r approvals for changes change and the inspection processes. The • H o nesty and integrity and Stirling Alliance Lead T eam deliberately • Put the All iance fi rst chose not to have inspectors. Instead they Prior to the start of construction all were ca lled Q u ality Mana ge r' s R epresentatives and were carefully chosen managers, supervisors and workers partic-


PROJECT

for th eir ability as well as the ease in w hich they wou ld adopt the all iance culture. To quote one of the Supervisors in a close out interview "I'1n amazed at how much more you can achieve when everyone is working towards a common goal".

Incentives There were three types of incenti ve in th e Alliance project. 1. The Site Allowa nce. An hou rl y site allowance was allocated based on performa n ce for the prev iou s mo n th in env ironment, public relations and safety. The lead team mon itored the pe1form ance an d established th e site allowance each m o n th based on agreed criteria for each Key Performance Indicators (KP I). Th e Alliance t eam pe rforman ce actual ly imp r oved eac h month so th e site allowa nce payments increased each month. 2. In the agreed R isk R eward process, fee modifi ers for th e soft key performan ce indica tors of environment, public relations and safety were agreed upon by the All ian ce Board. On ce th e criteria were establis hed the Board calc ulated the percentages the reward would be adjusted. 3. A key to the success of any construction project is to maintain or improve the levels of produ ctivity. Th e Stirli ng Alliance com m e nced constructio n on November 10th 1999 and worked at a high produ ctivity rate until the C h ristmas break. The challe nge for th e Alli ance was how to increase the produ ctivity after C hristmas w hen traditi onally the work com n1_itment at that time of year tends to be lower. The Alliance Manager presented a Produ c t ivity Based Bonus In ce ntive Payment to th e Allian ce Board for ratification. Th e basis for the proposal was that if work was completed ea rl ier than th e stretch target date the n this would represent a substan tial cost saving to th e Alliance. For every day saved, there were large savi ngs as there were no requirements fo r plant and lab our. T h e Produ ctivity Based In ce ntive Scheme ground rules were: • The final as-built direct cost must be below the Project Target Cost • There was no co mprom ise on safety, environment, quality and public relations • No additional plant or labour was to be allocated to the works • Ther e was no change in the hours worked Th e results were ou tsta nding. Th e p ipeline stretch target date was beaten by 16 working days. The pipe and road construction was thus completed before substantial ra in. Financially the saving to

IMPLEMENTATION

the Allian ce after all payments w as approximately Sl million. However this particular incentive was also successful in having a full y motivated workforce with a defin ed goal. T he mora le on the proj ect was very hi gh and all workers were driven to succeed by the financial carrot at the end. All workers on the project were rewarded. As the road construction team had to structure their program to allow for the pip eline to be laid at th e requi red rate, th ey also received incen tive payments. Th ere was no detrimental effect on the enviro nm enta l, public relations and safety perform ance duri ng this ti me .

Innovations Innovat io n was st at e d as b e ing important fr om the outset. T he key e lem e nts w ere to firstl y e nco u rage innovation and then ensure the proposal is quickly assessed before putting it in to practice. On a lump sum project, the approval process for any inno vative ideas can be long and arduou s. As the Stirling Alliance had th e key decisio n makers on site or readi ly availabl e any innovative idea was

acti oned quickly. As a result, a very positive cul ture was developed and personnel were encouraged to continue pu tti ng forward inn ovative ideas. The innovative ideas submitted by the team m embers were recorded in the Inno vations and P o sitive Outco m es R egister. In many cases there were monetary savings to the Alliance. The total assessed valu e of these savin gs was $725,000. Of the 60 recorded innovations i n th e R egister, m any had beneficial outco m es in safet y , qualit y, t h e enviro nment or pu bl ic relations.

Workshops, Reporting and Meetings A number of meetings were held before and d urin g th e co urse o f construction to ensure the work was being completed in th e most effi cient manner but also that th e aims and objectives of the Allian ce Charter were being met. T he course of events from the pre-construction inducti on workshops on 5th November 1999 to th e C loseout meetings in J uly, 2000 is described as follows: 1. Personnel attended an Alliance-specific 3-4 hou r indu ction on 5th November

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PROJECT

IMPLEMENTATION

6. C limate Survey Final R eport in 1999, prio r to the Alliance team mobilising to site. The inductions included an J anuary 2000. The pu rpose was to provide performance benchmark from the overview of the project presented by the perceptions of the Allian ce Team Alliance Manager, followed by three membe rs about ho w th e Alliance separate workshop sessions on safety, approach to the project was pro gressing. environment and public relations. Each In addition areas of improvem ent were of the 45 minute workshops involved a presentation by the manager or officer of identified at all levels of the Alliance. 7 . Smarts M eetings. Three m eetings that area covering the relevant Alliance were held with lead team members, policy and objectives (including stretch constructio n managers, quality manager's targets), key issues and requ irements representati ves and supervisors to ensure This was followed by an interactive session all innovative ideas and recommendations involving the workers in identifying were progressed. potential project impacts and developing 8. Pipe/Road Interface Meeting. The relevant management strategies. The purpose of the m eeting was to identify the indu ctions were concl uded with an issues prior to interface work proceeding outlin e of the financial incentives offered and to reach agre e m e nt be t ween to workers for achieving a high level of construction crews of the best way to performance in the areas of environment, manage any potential problem s. safety and public relations. 9. C lose O ut Interviews R eport. T he 2. Mobilisation of the Alliance tea m from interviews were condu cted in o rder to Perth to Harvey c ommenced once capture the perceptions of key project staff Ministerial and Environmental Protection on the strengths and improvement opporAutho rity (EPA) approval had been tunities in the Stirling alliance. Th e received on 10th November 1999. A interviews were aimed at determining the number of planned meetings were held effectiveness of the Alliance from the and SRO Consulting distributed minutes points of view of a variety of stakeholders. and action lists on each occasion: T hey included all managers and super3. Lead team n1eetings were con du cted visors, Lead Team m embers, Board weekly initially and later fortn ightly. members, Water Corporation Person nel T hese were effective in encouraging and the Shire of Harvey. From this report positive o r negative aspects could be communication bet\¥een Managers and in identified. identifying and resolving any issues. The facilitation of these m eetings and the 10. Newsletters were w ritten each month whol e Allian ce proc ess by SRD and distribu ted to Stirli ng Allianc e personnel and stakeholders. Co nsulting assisted the Alliance to m aintain foc us on key issues and to meet 11. C lose Out Meetings. Final Close Out and in many cases exceed project targets. meetings we re held in July, 2000. 4. M onthly performance revi ews were Stirling Alliance Charter held to rate and document the workers The Alliance Charter was signed by prior month's perfo rmance against stretch Board M embers, Lead T eam m embers targets and several discretionary criteria. other AIJiance managers and sup ervisors. Hourly site allowance was adjusted up or The C harter defined the following specific down fo r the following month, depending objectives: on the results of the performance review. • Achieve an environmental outcom e that Th e reviews were effective in identifying impresses the DEP/CALM/ EPA problem areas and / or areas for potential • Develop innovative processes to assist improvem ent. Feedba ck was provided to us in doing better than project targets employees via an internal newsletter. The • Deli ver and maintain an integrated and incentive payments provided motivation equitable Alliance team, with a capabili ty to Alliance personnel to achieve a high to move on to future proj ects standard of performance in Environment , • D eliver water downstream to the next Public Relations and Safety. lt was stage for testing and commissio ning prior essential to ensure em ployees focussed on to target date these soft Key Performance Indicator • D eliver a quality product to specifica(KPI) areas, in addition to m eeting tions. program and budget targets. • Maintain a committed and motivated 5. Board Meetings were held monthly and workforce that is efficient, productive and attended by the three Board Members, the strives for continu ous improvement Alliance Managers and SRD Consulting .. • Complete project below cost and share Board R eports were compiled by the Lead profits Team each month and presented to each • Com plete and produ ce an award Board m ember two days prior to each winning project that is envied by our peers meeting. 30

WAT ER DECEMBER 2001

• Maintain harmonious relationships with all those that live, work and recreate in the vicinity of the project • H ave zero L Tl's and zero traffic accidents to workforce and public At the end of the proj ect the perforn1ance was m easured again st the objectives. Every objective was met except for the last one. Th ere were two LTl's and one traffic accident on the project. T he proj ect was such that the risk of LTI's and traffic accidents was high. The program of work was tight and there we re long working h ou rs. On the roadworks there were many potential safety issues partic ularl y w ith th e constructio n of the ca useways. The pipeline construction in the river valley was particularly dangerous du e to the confined clearing zone and the steep slop es. The overall objective was to "complete the Stirling to Harvey section of th e pipeline w hich enables delivery of water to T amworth in the least time and cost." In essence all the results of the Alliance work and th e achievem ent of the specific objectives have shown this objective was achieved. T he behavioural commitments stated in the charter were alJ achieved as a matter of everyday behaviour by all in the Alliance. T hese were: • Promote alliance objectives • Treat each other equally and respect individual points of v iew • Foster an open and cooperative team enviro nment • Behave unselfishly and share information, risks, resources, skills, rewards and awards • Encourage breakthrough thinking and best practise • Protect the environment, people and property • Act with integrity

Risk Management T he Stirling Alliance Lead T eam consisted of representatives from all the project participants. This meant the project was planned and managed by a team working together to obtain the optimum outcome for the project. T he Lead T eam was on site all the time and in the one location. As a group they had the necessary expertise and experience in all required asp ects to m anage the risks of the project. The Lead Team developed quickly into a closely knit team and communication was excellent. Where there was a potential risk to proj ect participants' resources or cashflow th e situatio n was quickly


PROJECT

addressed. The aim of the Lead Team was to identify the risks early and implem ent risk n1.anagement strategies to mitigate the risk . As this proj ect was constructed in a tight timeframe and there were many enviro n menta l and soc ial constrai n ts upon the Alliance, the potential and impact of risk was great. The success of the proj ect was p artly due to the manner in whic h risk was managed. T he reasons risk m anagement was successfu l are as foll ows: 1. Allian ce members worked as a team with excellent communication. 2. H ad expertise on site and backed u p with experience and knowledge of the project from other project participants 3. Identified risks and impl em en ted risk management strategies ea rly 4 . Prin cipals of OAP o n si te or close to the project to faci litate decision making 5. Faci litator to assis t with ri sk management stra tegies 6. OAP and clien t representati ves io nsite were very experienced in pipe and road constru ction 7. Alliance c ulture meant all alliance m em bers contributed to risk managem ent

IMPLEMENTATION

The responsibility for risk was passed on to those in the best position to identify it early and manage it. As each area had managers and officers chosen as "best for the job" from three organisations then these people were well qualifi ed to accept assignation of risk.

Summary While th e Stirling Alliance was very su ccess ful , there were s ignificant challenges and hurdles to overcome in the project. The critical lesso ns learnt from the Stirling Alliance project, which could be adopted for other similar proj ects, are as follows • Defin e th e scope acc urately and minimise unknowns • Assess if proj ect is su itabl e for an alliance • Learn from other similar allian ces • Appoin t a facili tator experienced in all iance contracting ea rly on the process • Plan the OAP selection process • Ensure Alliance partners will adopt alliance culture • H ave pro b i ty consulta n t present th ro ugh selection process • D evelop the PTC jointly, with an auditor

• Sign off the agreement and risk prior to start of construction • D evelop the cu lcure with all Alliance members before start of construction • Choose carefu ll y th e Lead Team members • Adopt the behavioural aspects identified in the Allian ce C harter • Introduce appropriate incentives • Encourage innovation • Identify and manage risk earl y • Incorporate in the Agreement a quick and effi cient way to m anage scope change • E ncourage involvement in the Alliance by th e clie nt and oth er stakeholders • Ens ure fast and effective decision making • Identify the needs of stakeholders, landown ers and the local public.

The Author David McGill is Senior Engineer, In frastructure Pla n ning Branc h , Water Corporation, PO Box 100 Leedervill e WA 6902, and was the A lliance Manager for th e Sti rlin g Alli ance T elephone 08 9420 4208, david.mcgill@ watercorporati on .com .au

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PROJECT

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ALLIANCE BRINGS INNOVATION: WOODMAN POINT WWTP K Bartley Abstract

Allian ce to carry o u t the Woodman Poi nt Environ mental Enhancement Project. The partic ipa nts in the Woodma n Alliance are the Water Corporation together with C lough Engi neering Ltd and Brown and Root Services Asia Pacific. T he Water Corporation chose alliancing as the project delivery strategy for the Woodm an Point Project havi ng regard to the va lue, nature and complexity of the project which was required to be designed and constructed with operational and environmental goals and a focus on min imisi ng whole- of- life costs. The all iance was designed to provide a co ll aborative contractua l relationsh ip with incentives for excep tiona l pe rforman ce , cos t The SBR has the capacity to hold 160 megalitres savin gs without sacrifice of quality, Introduction of wastewater. Aeration testing is an important and a sharing of the benefits of cost The Woodman p O i 11 t part of the commissioning process. savings. W astewater Treatment Plant was Alliancing was also considered to first conunissioned in 1966 and is the diam eter con nectin g sewer and a 1.2km offer the means o f best incorporating the largest of the three main treatmen t plants 1400 NB delivery pipeline. W ater Corporation's exp ertise together servici ng sewered properties in Perth's Th e proj ect is being deli vered by way with that of the contractor and consultant, metropolitan area. It had been previously of a project alli ance which h as led to to readily allow for c h ange and upgraded to its present capacity serving significant incorporation of innovation, innovation in design and construction, around 625 ,000 people, and is currently cost sav in gs and other benefits. and to meet objectives of exceeding treatin g around 105 m ega litres a day. busin ess as usual benchmarks for safety, Project Delivery Strategy The scope of works for the W oodman en vironmental performance and stakeP oint Environme ntal Enh an ce ment Th e Water Co rpo ration is th e holder relati ons. P roj ect is th e d etail ed design and principal provid e r of water and constru ction of: The Treatment Process Works wastewater services th roughout W estern • works to increase the Woodman Point Au stral ia. It formed th e Woodman The current process used at Wa stewater T re atm ent th e W oo dman P oint Plant ca pa c it y to 160 Wastewater Treatment Facility megalitres/ day including a is primary treatment with: new advanced Secondary oennl!nl!J PenmeterWal PtrBasin • coarse sc reening to remove / 62mHigll Treatment faci lity, sludge any large obj ects (papers and thickening fa c ilities, a rags) before passing through treated e fflu e nt sto rage tan ks to remove grit; reservoir and odou r contro l • settlin g tanks to remove facilities; TtHtti:1 Et'IWIC ,......,.,,. suspended solids; • disc harge of secondary t B~lng0¥n the p rimary t reated treated effiu ent to ocean, ........... wastewater from these tanks instead of prim ary treated receives no further treatment sewage. before bei ng discharged into Mi.eel uquor Recytle • works to in crease th e fJ(ces, ACtN'attd Sluclge Aeration Pipes To Pumps. 2 Se11 Per Hh 'Nltha'Nal System Diffusers On Tank the ocean. BISW\ (rachtDu1) .,.,_, J H1· main sewer and pumping ""°' 160m0Ia. • Anaerobic digestion of settled capacity to the treatment solids plant including a new 4,600 Figure 1. Diagram illustrating the components of t he litres/seco nd Wastewater The products of sludge Sequencing Batch Reactor - the first of its kind being round in Pump Statio n (Munster No. d iges ti o n are bi o - gas and shape. 3) with a 1.6km, 2250111111 stabilised biosolids. The bio-gas Near the southwestern fringe of the suburbs of Perth a $ 150 rnill ion proj ect for am plifi cation of was tew a t er co nve ya n ce a nd treatment faci lities is at an advanced stage of construction. The proj ect will meet projected increases in wastewater flows, produce a higher quality effluent and improve odour control. The major featu re of the proj ect is a new advan ce d secondary tr eatment facility, an innovative sequential batch reactor. This pap er describes the proj ect works an d outlines the method of project delivery, w hich involves a project alliance .

/

32

WATER DECEMBER 2001

,,,.


PROJECT

IMPLEMENTATION

New inlet works provide efficient removal of foreign matter larger than 6mm to avoid blockages further down the stream.

As the process is a batch system, continuous treatm ent is obtained by sequential operation of th e fo ur basins. C ommonly th e cycle is: fill and aerate fo r 2 hours, settl e for 1 ho ur and decant 1 hour. Thus at any one time the respective basins will be at d ifferent stages in the cycle. With a patented control system wh ich allows fo r some overlapping of cycles, the SBR has bee n designed to acco mmodate the peak flow of 4600 li tres/sec. T he usual design of reactors with rectangular tanks and feed from the centre of one side has deficiencies. Amongst these can be short circuiting and the presence o f " dead pockets" li miting the efficiency of th e aeration process. The refi nement adopted by the Alliance was to design a circular tank, with four equal sized com partn1ents. T he innovative shape impro ves mixing and aeratio n effi ciency with 'dea d' co rners eliminated and control parameters more accura tely measured. T he numb er o f sludge pumps and pumping costs have also been redu ced.

- mainl y meth ane - is used on site as a fuel in engines to produce heat and generate electricity. The stabilised material is dew atered, then carted away to be used in soil enrichm ent.

Secondary Treatment T he upgrade of th e plant involves se condary treatment processing to fur ther remove solids and redu ce nitroge n by nitrification/ denitrification before discharge to the ocean. Its design capacity is 160 ML/ day and the target eflluenc quality: BOD < 20 mg/L, T SS < 30 mg/ L, TN < 15 mg/L Secondary treatment is perfor med in an in novati ve circular Sequential Batch R.eacto r (SBR) as shown di agram matically in Figure 1. T he SBR is 160 metres in diameter w ith concrete floor and p erimeter walls 6. 2m hig h and is separated in to 4 quadrants or basins. Extending from the central inlet stru cture and provid ing the d ividing walls of each quadrant are large baflled rectangular concrete tanks. These constitu te the bioselector zones. In operation the primary treated was tewa ter is bro ught to the centre of the SBR. Penstocks direct the flows through the appropriate bioselector zone w here it is mixed with bio logically activated material (mixed liquor) . It then flows into the selected basin near the ce ntre of th e SBR Galvanised steel aerati on pipes ex tend fro m the nea rby Blowe r H ouse and are supported o n steel trussed bridges above and traversing the fo ur quadrants. T hese air supply pipes vary in size from 900 to 300m m in diameter. From the supp ly pipes on the bridges th e air is deli vered to fi ne bubble cylindrical membrane diffosers installed on a network of PVC distributor pip es across the floo r of each basin. T here are a total of 51 20 air diffusers. Following aeratio n and settlement the clear liquid is removed by way of decanters. There are 8 stainless steel decanters per basin installed around the perimeter wall. The decanters are lowered into the liquid and deliver effiu ent th roug h th e wall to a perimeter collection channel.

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WATER DECEMBER 2001

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PROJECT

IMPLEMENTATION

The circular shape and control system are among the innovations which have significantly reduced the 'footprint' and lowered the cost of the SBR. Five multistage centrifugal blowers supply the air requirement. T hese are electric motor driven with variable speed drives. The blowers are 500/450 NB, each with a capacity of:21,000 Nm3/ h, the motors 500 kW. T he Blower House is a portalised structure using tilt-up precast concrete panels. Beneath the main blower machine hall is a 4 111 deep reinforced concrete basement housing the main air inlet and outlet manifolds.

Other Upgrades and Plant Extension In addition to th e new secondaLy treatment the fo llowing upgrades and extension of the existing Woodman Point Wastewater Treatment Plant are included in the proj ect : • A new inlet works of increased capacity incorporating fine (6mm opening) stepped screens, screenings wash and presses, and screw-type conveyors to bins for disposal; • Modification of the primary sedim entation tanks fo r increased capacity, fitting of new skimmings scrapers, and importantly concrete protection work and fitting of covers to contain odours, w ith fou l air extraction to chemical scrubbers. The removable covers are aluminium and cover an area of 3680 square metres. • Provision of new sludge thickening facilities an d upgraded sludge treatment facilities. R otary screw thickeners are being installed w ith polyelectrolyte batching and dosing fo r a design thickened sludge flow of 800 1113/ day;

Decanters inside the SBR are lowered simultaneously to decant the clear liquid off the top of the effluent after the solids have been allowed to settle.

• A third 600kW reciprocating gas engine driven generating set will add to the Energy Recovery Facilities. • A fi nal eilluent 45 ML storage dam has been constructed. Its function is primarily to balance the flow to the eilluent outfall pipe. This is an excavated and earthen wall (limestone) dam with a syn thetic liner.

Conclusion T he project is plan ned for completion of commission ing in March 2002. Commissioning will be a progressive process with some components able to be conrniissioned independently of oth ers. T he four basins of the SBR are being commissioned progressively. Process commissioning commenced in October 2001. The delivery of the project by way of the project alliance has provided opportu nities generally not available with conventional contracting strategies - the opportunity to challenge the design and scope of works and utilise a team drawn from the vario us participant companies on a 'best for project' basis to work together to produce cost savings whilst designing and constructing a quality facility. The result to date is well meeting these expectations. The Woodman Alliance has achieved outstanding results including significant in novation in design and construction. The project, p roceeding to be commissioned on schedule, is fo recast to be completed for a capital cost below budget, and with a design incorporating long term operational cost savings. It has received a Worksafe Gold Award for Occupational H ealth and Safety managem ent. It has measured performance indicators in the areas of environmental achievement and comm unity relations as well as safety which are all ranked as ou tstanding.

The Author Ken Bartley, a civil engineer, is a Project Director w ith the Water Corporation, and curren tly seconded to the Wood m an Alliance in a coo rdination m anagement r o le for the Woodman Point E n v i ro n me n tal E nhancernen t P ro j ec t. ken.bartley@wa2 1.com.a u 34

WATER DECEMBER 2001


RKS

UBLISHED BY THE AWA AND THE AUSTRALIAN WATER & WASTEWATER OPERATORS ASSOCIATION

WELCOME TO WATERWORKS Welcome to the first edition of WaterWo rks. As the name suggests, this magazine is dedicated to daily operational activities within the water industry. Over the last ten yea rs the wate r industry has experienced a lot of change. C ustomers have become more aware o f drinking water quality and now expect a consistent high quality produ ct. This expectation places increasing demands on Water Treatment Plants. In many cases co nstruction o f new treatment plants or major upgrades have been necessary. Operations staff have had to master new more complicated plants or j uggle the operation of the old plant while modifications have been made to their plants. Th e new fo cus on the management of distri bution system s recognises that the water distribution system is more than just a system of pipes and has a profound effect on water quality. Similarly, environmental expectations r e quire greater em phasi s o n the managem ent of sewer reticulation systems to prevent spills and limit infiltration. Sewage T reatment Plants have also faced the need to m eet higher eilluent quality requirements and regulators are placing increased pressure on the development a nd impl e m e ntation of sustainable operational systems including reuse. T o meet this changed foc us, both water and wastewater treatment plants are becoming increasingly complicated with on line instrumentation, have sophisticated m onito ring including SCADA systems and are computer o r PLC controlled. Plan t laboratories are being used for a greater number and variety of tests, and data is now being m anaged in databases rather than the old plant run sheets. New equipment is released at such a rapid rate that it is difficult for operators to be aware of the instrumentation available or to trial new equipment. All these changes h ave placed increasing demands on the skills and knowledge of field operation staff and technical support staff This magazine is an idea I have had fo r some time to provide a means whereby real life operational experience

Pictured is the south aeration basin at the Morwell Wastewater Treatment Plant. See the article on page 44 by M ick Cook for more information about the upgrade of the Morwell STP.

can be made available to others involved in water industry operations. M any d ifferent and exci ti ng thi ngs are happening in different parts of Australia. The magazine will offer the opportunity to report on the actual experiences of operational staff and allow a transfer of knowledge in a format that should be easier to understand than so me other more technically based publications. We will produce 2 editions per year to start with , and the aim is for papers and reports to be contributed by field and technical support staff on any topic associated w ith the day to day operations of treatment plants and distribution or sewer reticulation systems. Since the concept o f the m agazine originated in Victoria the first edition reflects a bias to this area of Gippsland. Initially, we expect contributions to the magazine to be slow however we have access to a range of articles and also to pap e rs and posters from the V ic AWWOA conferences. These will be used to supplement the content of the magazine from time to time. We would hke to encourage operations staff to submit articles from the out set. We will also identify potential aut h ors and encourage them to contribute. Ultimately the ongoing

success o f the venture will depend on support from operational staff Th e m agazine will attempt to provide a balance between water and sewage and between treatment and pipes however at times it may appear to be skewed to one mode or the other. I hope the articles will be of sufficient interest for all, regardless of thei r particular discipline at this stage. And so with one bold step and the production of this the first edition, onwards into the future. Peter Mosse Editor

CONTENTS In Brief

33 34

Balancing the Wastewater Equation

40

Upgrading the Morwell Sewage Treatment Plant

44

Practical Experiences with Particle Counters

47

Comment

WATERWORKS DECEMBER 2001

35


Australian Pollution Engineering Ptv Lid P.O. Box 200 , Bendigo, Victoria, 3552 Ph: (03) 5448 8317 Fax: (03) 5448 8702 Email: ron@auspolleng.com.au Managing Director: Ron Bergmeier (0418)509817

Australian Pollution Engin eerin g specia li se in the management of slu dge. Contract services include dredging, mechanical sludge dewatering, air-drying, slu dge disposal, beneficia l slu dge reuse and sludge surveys. Equipment for hire includes: I 0-40m 3/hour • Belt filter presses • Centrifuges l 5-80m 3/hour • Excavators, swamp dozers, front end loaders, tippers. • Dredges , pipelines, generators, pumps. Other services include the manufacture of activated sludge/ BNR pilot plants and biological scum harvesters. APE offers a complete service and solution to your dredging, dewatering and site rehabilitation projects.

Proud Supporter of the Australian Water and Wastewater Operations Association AUSTRALIAN POLLUTION ENGINEERING ...,1

BENDIGO

(054) 488 .317 u,._f, Dtwattring Unit


ED I TORIAL

I wou ld like to congratulate Peter Mosse fo r h is initiative and effo rts in starting this important magazine . A publication such as th.is, with an operator fo cus, h as b ee n di sc usse d at A WW O A Comm ittee level for quite som e time but until now has not been possible. W e are pleased that Peter has taken up the challenge as inaugural Editor, and we look forward to assisting him in th e produ ction of fu ture editions. In this first editio n, I' d like to take th e opportu nity to introduce yo u to th e AWWOA - Au stralian W at er and W as t ew ate r Ope ra t o rs Assoc ia tio n. Historica ll y, in 1973 a sm all , but enthusiastic grou p, intent o n in creasing th e kn owledge and skills base of wastewater operators, formed the AWWOA. In those days the re were no training courses for op erators and, after m uch hard work, the efforts of this group was rewarded with the fo rmatio n o f the Victo rian W ater T rainin g Centre. T he link w ith th e deve lopm ent o f trainin g has been maintained and one of o ur C ommittee M.embe rs, M r John Harris, is the current vice C hair o f W IETTA-Water In dustry Ed u cati on Tra ini ng Associatio n o f Australia. As with the ea rly days, m uch hard work has been do ne over a number of years to develop a Water Indu stry T raini ng P rogram and to gain its National accreditation . T h is program inco rporates study modul es co vering nu merous tasks associated within the water industry inclu d ing water and w as t e w a t e r tre a t m e n t , ca tch m ent managem ent, headworks and supply, reticulatio n system co nstru ctio n and m aintenance, and irrigation management to name but a few. These courses are now up and running and som e Certificates have already p rese nted to operators und er the n ew system . Th e m embership criteria and services o ffered has been significantly expanded by th e Asso ciation since the early days and we now o ffer membersh ip to any person within Austra lia undertaking a rol e in ANY pa rt o f the water cycle. The A WWOA has constitutional goals of info rmatio n transfer and development of member skills. T o facilitate this, activities such as seminars and con fe rences are organised , a quarterly newsletter entitled Operator is produced, job advertisements fo r position vacant are distributed , and a website is maintained. Please take the tim e t o l oo k ove r t h e webs it e at www.awwoa.o rg.au n ext time you are

surfin g th e net. It contains much information including copies of past conference papers and newsletters, links to corporate m embers and oth er websites, a copy of our Constitu tion , and a membership application fo rm fo r those so in cl ined . AWWOA Members get all th ese benefits plus no w 2 editions of th is magazin e, for th e exorbitant fee o f $10 + C ST = $11 per year. In relation to this magazine, its success will depend entirely on th e contributio n o f you - th e o perators. From my observations over a number o f years, a lot of operato rs sell th emselves short when it com es to co mmu nicating what th ey do, or more impo rtantly w hat they have ach ieved. You need to consider that we all work in th e sam e industry with sim ilar issues relating to o ur jobs no matter w hat fu nction we undertake w ith in th e water cyc le. E ve ryo ne, includin g rese rvoir managers, water o r wastewater plant

operators or reticulation maintenance stal:f, have prob lems with plant, equipmen t, sho rtages ohime, money and labo ur and are u nd er th e sam e pressure to deli ver qu ali ty produ cts or services at all times. A pro blem worryin g yo u right n ow may be exactly the sam e as one fac in g a number o f operators across the breadth o f Australia . Someone else may have already fixed th.is problem and it may be beneficial to yo u if yo u knew h ow they did it. Conversely, it would be great fo r oth ers to read ho w yo u fi xed a p roblem no m atter ho w big o r small. So metimes the simpl est so lutions are overlooked in the u rge to gen erate a high-tech or m o re co mplex fi x. 1 urge you to take up the challenge and get in volved by writing an article and look fo rwa rd to readin g contributions fro m water industry practitio ners located all over Australia. R 11ssell Mack A WWOA President

AWA COMMENT I am really glad to see this publication hit the streets, tha nks to tl1 e energy of Pete r M osse a nd his colleagues, th e collaboration between the Operators' Association in Victoria and the Australian W ater Associatio n and, of course, the support of H allmark Ed itio ns. Although we are told repeatedly that today's is a wired world, the truth is that most people, given half a chan ce, prefer to read som ethi ng in hard cop y, prefe rab ly ni cely laid o u t, c o l ou rful and intere st ing. T hi s magazine is intended to fill th.at gap fo r Australia's water operators. T he journal, Water, that includes this m agazine has a long, proud tradition of bri nging high quality technical papers to Australia's water industry. Not many of those papers have appealed to the p eopl e at the coalface, though, because tliey tend to be tlieo retical and complex, rather than straigh tfor\vard and practica l. W hat op erators need is inform ation that talks about their daily challenges - how th ey can work b etter , smarter , more safe ly, and improve tlieir prosp ects of advan cem ent in the wo rkplace. I hop e th.at the articles collected here are going to answer those needs.

M y own, specific area of interest o n the operations fro nt is training, as I have a long involvem ent with WTET AA, the association that represents th e traini ng interests of the water industry. Afte r many years of stru ggle , a new national T rai ning Package fo r die water industry is abo ut to be fo rmally ado pted , free ing up train ing resources across the country. O nce the Package is signed and sealed, the challenge is to see its contents implemented ; that w ill be hard because operato rs are spread thinly across Australia and th.ere are not that many traini ng p roviders. For W IET AA to be effective in getting train ing implem ented , it needs to know w ha t p eople in water operatio ns want and need in the way of train ing and qualifications. A very helpfu l step ther e w ill b e direct feedbac k from operators in the fi eld . Pl ease contact m e o n th e p h one (02 9 413 1 288 ) o r b y e - ma il cdavis@awa.asn. au if you woul d lik e to spell o ut any training n eed, co ncern or idea. Enjoy th is first issu e of WaterWorks and I hope w e can bring yo u many mo re issu es, design ed in your interest. Chris Davis Executive Director, A W A

WATERWORKS DECEMBER 200 1

37


IN

Floated Sludge Removal Shepparton Water Treatment Plant by Neal Collins, Go ulbum Va lley Water Sheppartons' Plant No . 1 is the newest plant on site and was co nstructed in 1997 . This new plant is a dissolved air floatation filt ration (D.A.F.F. ) water plant which is comprised of three 13 ML cells. T he nominal capacity of Plant No. 1 is 40ML. /day. The D .A.F. process involves the introduction of air saturated water (water with micro bubbles) to the coagulated water as it enters the filter cell. This effec-

WATERW9 RKS Editorial Committee Peter Mosse, Editor mossep@gippswatcr.com.au Russell Mack mackr@gippswater.com.au George Wall GcorgeW@gvwater.vic.gov.au Direct mail to: WnterWorks Editor cl-Peter Masse, Gippsland Water PO Box 348, Traralgon, Vic 3844

Advertising Brian R a ult, Nation al Sales Manager H allmark E ditions PO Box 84, Hampton, Vic 3 I 88 Level 1. 99 Bay Street, Brighton, Vic 3186 Tel (03) 9530 8900 Fax (03) 9530 89 11 Mobile 0411 354 050 Email brault@halledit.com.au

WnterWorks is the publication of the Australian Water and Wastewater Operators Association (A WWOA). It is planned to be published twice yearly as a bound insert in Wnter Jo11n1t1/. Neither the AWWOA nor the AW A assume responsibility for opinions or statements of facts expressed by contributors or advertisers. All material in WnrcrWorks is copyright and should not be reproduced wholly or in part without the written permission of the Editor.

Contributions Wanted WarervVorks welcomes the submission of articles relating to any operations area associated w ith the water industry. Articles can include brief account.~ of one-off experiences or longer articles describing detailed studies or events. These can be c mailed to a member of the editorial committee or mailed to the above address in handwritten, typed or printed form. Longer articles may need to be copied to CD and mailed also.

38

WATERWORKS DECEMBER 2001

BRIE F.

tively do es away with the sedimentation stage of conventional treatm ent and causes the flocc ulated particles to rise to the surface with the assistance of micro air bubb les. Th e clea r water then descends through the filter bed, below each cell. The aerated sludge forming on the surface of each cell then needs to be periodically drawn off. The process of sludge removal is performed by flooding the cell above the spi ll way, which is at the opposite end of the cell inlet. This process is referred to as ajlont ~ff It is this process we looked at improving, as it uses a large volu me of water, which was being sent to w aste. At th e time of commissioning the float off occurred every two hours, for a duration of 6 minutes. It was calculated the water wasted d uring this 6 minute period was 42,480 litres. Our operators found that by using a hose to assist the sludge towards the spill way, during th e float off, it would shorten the duration of the float off This led us to investigate the possibility of sprays, as a permanent fixture, to assist with the sludge float off. T he mai n objective of this spray system is to reduce the time of'float off which in turn minimises water wastage. lt has seen the sludge float times reduced from 6 minutes to 2 minutes. We have calculated the water used in a float off, with the sprays in operation, to be 14,160 litres. A saving of 28,320 litres per float. When you n1.ultiply this by the number of floats in 20 hours of operating time (typical run time per day), then multiply that by 3, being the number of cells. It adds up to a saving of 849,600 litres per day. This wasted wat er was sent to Shepparton de-watering plant. It has made hu ge savings on the operating cost of this plant.

'Launder Scrubba' by Trevor Gordon, Go11lbiim Valley Water In the past the cleaning of the de- cant trough s was don e manually with oversized toilet brushes. T his involved wa lking ou t in each trough and physically scrubbing them. This method was physically demanding and time consuming. A better way was needed ... ... . At Shepparcon we are currently developing a new piece of machinery. 'The Dirty Scrubba.' It involves the cleaning of the water collection (de-canting)

troughs on the sedimentation tanks of our conventional Water Treatment Plants 3 and 4. With ongoing emphases on health and safety in the workplace and with the risk involved in this balancing act it was suggested we co me up with a fall arrest system for our operators to use while carrying out the cleaning task. Th ere were funds in the budget aUocated to this project. After som e investigation into cost and feasibility of this high wire act we discussed the possib ility of bui lding a machine to do the cleaning job for us and so the 'dirty scrubba' was created. A local engineering firm who have worked with us on the development of the dirty scrubba made the prototype . The cost of this project will come in well below the amount budgeted originally for the first suggestion of a faU arrest system . Th e manual labour has been all but eliminated as the dirty scrubba works as a stand alone cleaner with rotating brushes self propelling it along the troughs. Although it still needs so me work to maximise its cleaning ability and improve its user-friendly aspects we are very happy with the outcome. Still on the drawing board is the internal trough scrubba and the feedback from the engineer su ggests this wi ll be the simpler of the scru bbas and we hop e to have this fully op erational in the next month or so.

HELP!!!!!! Any Ideas??? This section is available for readers to raise issues or ask direct questions relating co unsolved operational problems. Readers are invited co respond directly to the author of the help article and also through the pages of the magazine so that others may benefit from the experience.

Alum Problems Gippsland Water has for some time now been experiencing problems with crystals present in alum in the dosing system at several of its WTPs. The crystals don 't seem to be present in the delivered product o r in the tank but are appearing in dosing pumps and back pressure valves on the dosing lines. Are any other o perators experiencing this. If so how have they solved the problems. M ichelle Colwell (51 774 600 or colwellm@gippswater.com.au).


IN

This un it was manufactured by Goulburn V alley E n g ineering. Fo r furt h er in forma ti on, co n tact T revor SecculJ on 035821 2266.

Propeller Blades at the Moe STP? by P aul K eating, T reatment P la11t O p era tor, Gippsland W ater No, not propeller blades but cwo stainless steel pipes that are now crushed flat, and all it took was 2.7 metres of head pressure. Moe STP has three treatment ceLls (Sm x 4111 x 4111), each holding on average four mi ll ion litres. Th e raw sewage is introduced into each cell by its own manifold whi ch is a 370mm stainless steel pipe with fou r 370mm droppers. Cell No3 's manifold is fed by a 370111111 stainl ess steel pipe which runs through Cell No 1, at 1.6 m eters above the floor of the cell. Cel.l No3 was the first cell to be drained fo r modifications to be carried out. After draining and cleaning, inspection took place. W hen we looked up th e inside of the empty pipe we didn't like what we thought we saw; and poked a torch up and had a better look.

BRAIN TEASER M11ch ef what 111e do relies OJI calculatio11s. ill this segment 111e 111ill pose some real life operatio11s proble111s a11d give you the cha11ce to hm1e a go at working out the answer. The 111orkings will be provided i11 the 11ext edition cif the newsletter. Blacks Block!!

You n eed to disinfect water flowing in a 750 mm diam eter main at a constant rate of 80 I/sec. Yo u have a stock solu tion of 3% (w/v) hypo. What we fi rst thought was that the top of th e pipe roof had collapsed to half way and the rest was sludge. Out with the hose and another look revealed that the top had collapsed 50% but also the bottom had collapsed 50% as well - a completely bl o cked pi pe. After a few expletives(#$%"&0) the questions flew quick and fast. First thought was to determ ine how much of the pipe was squashed and how badly. A camera inspection from either end was a possible

ACROSS

DOWN

1 Next step after 4 down 7 Excrement 9 T his helps the pay packet 11 Type of water treatment (abbreviation) 12 Water is 13 Brekky food

1 The movement of liquid through a pipe

14 Important fo r brew 15 Flat 16 Copy 18 Salty 19 Not the most 20 Nothing 21 23 24 25

Do this to your l's Have a go Information technology (initials) Added to water for dental health

2 Short fo r operator 3 Chemical version ofB. O.D.

4 C hange the surface charge of colloidal particles 5 High ____ pump 6 What the water and wastewater plan t

are used for 8 To move water through a system of pipework 10 A method used to send and receive information and control items of plant 14 Place where armed forces eat 16 Look after 17 Put __ , To work hard 22 Used to propel a boat 24 Identification (initials)

• W hat flow rate is required from the dosing p ump to deliver hypo to the m ain to achieve a tota l chlorin e residual of 0.6 mg/ 1? • H ow m uch hypo w ill be used per day assum ing the water flows in th e pipe for 12 hrs/day? • H ow long wou ld it take fo r an increased dose of chlorine to be detected 2 km away along the same pipe? option, but we located a piece of 5011111, pvc and probed the damaged pipe from the surface. It felt like 13 metres out of 20 metres with problems, forge t the camera!! Th is raised a lot of qu esti o ns and a lo t of possible answers. Thinking vacuum was th e cause of our problem , we decided to fabricate a new pipe (to origi nal spec ifications, wh ich turn ed out to be all custom made,) and then get divers to rem ove th e damaged pipe and install the new p ipe . W e allowed two weeks for th e delivery of pa res and to organ ize eveiy thing w e thought we needed, and then we were into it. T he work took 12h rs but eve1y thing went to plan and we were back in action. Thjs was a T hu rsday. Friday every thing was still OK - BUT on Monday the cell that was supposed to be empty was now 3/4 full. The pipe had fa iled again ...... Bugger! This time concerned phone calls to fra ntic engineers confirmed chat an empty 270mm stai nless steel pipe with 1.5mm wall t hickness ca n only w it hstand 2 .7meters o f head pressure . A lot more questions and possible answers flew everywhere, and this time we decided to stay with 270mm stainless steel bu t w ith a wall thickness o f 2.5mm (5. 2 meters head pressure). Two-and-a-half weeks wait for parts, eight hours this time to replace the damaged pipe (getting good at this) and so far no problems with stainless steel pip es reducing in diameter. So if someone can explain to the engineers (they are the ones scratching their heads) and the rest of us, why a 13 m etre length of pipe would completely collapse flat one way fo r 6 metres and then the rest of its length collapse at 90° to th e firs t half please feel fr ee to enlighten us. • Paul K eating (k ea tingp @gippswater. com. au) is a Sewage Treatment P lant Operator at Gippsland Water and has opera ted the Moe S TP for 5 years . WATERWORKS DECEMBER 2001

39


T H E

WASTEWATER

EQUATION

BALANCING THE WASTEWATER EQUATION George Wall - Wastewater Specialist, Gottlburn Valley Water, Vic; Secretary, Australian Water & Wastewater Operators Association (AWWOA) Lagoon based systems are used for n1any purpo ses at Wastewate r Management Facilities (WMF), including primary or secondary treatment through to maturation/irrigation storage. Ask yourself the folJowing: • H ave you ever been caught with too much water in your lagoons due to heavy rain or unusual even ts? • Are you able to identify problems or malfunctions with yo ur p lant or equipment early? • Are you able to predict in advance when to take action or do you rely on crisis management? • Would you know the hydraulic impact of accepting efiluent from a new indust1y?

If you answered 'No' to any of these questions, I suggest you consider the development of a mass water balance model. I can hear some operators m umbli ng - "yeah sure, how hard is that going to be?". T here have been models designed for everything under the sun but most of time the model designer overcomplicates things, making them unattractive for operators to use. The key is to go back to the basics and provide a simple model that all operators with access to a PC can easily understand and use. A simple model has been used at a number of Gou lburn Valley Water WMF's for many years. This model ha s pro ven reli able at diffe rent plants, both large and small, and is used to predict potential operational

problems, allowing operators to develop appropriate water management plans welJ in advance of any need for action.

What information do we need to develop a mass water balance model? Effective models rely on quantifiable inputs and outputs. Inp uts include raw waste in flow to the plant, rainfall collected in the lagoons and returns to the plant (such as runoff coll ected in reuse dams following irrigation). Outputs include reclaimed water for irrigation, evaporation losses, and offsite discharges. In addition, we need so me physical information on the lagoons. Surface area is important to calculate evaporation; design freeboard or 'air space' to ensure the stabili ty of the embankments and avoid overtopping by wave action; a means of measuring the actual volume held in storage to alJow predictions by the model to be cross checked against real data; and access to weather data primarily rainfall and evaporation.

Model Figure 1 shows a simple mass water balance model fo r the fictitious Muddy Creek WMF. We can use this model to track flows in and out of the plant and, more importantly, to determine w hen and for how long, we need to discharge to the Muddy Creek.

What do the terms in the model mean and where do you collect the necessary data? The figures entered into the model are normally monthly values, with all flows recorded in megalitres. If an operator wished to run the model on any particular day during a month, cumulative values from the start of the month to that day are required for all parameters otherwise the model outcomes may not be sensible. Evaporation and rainfall

Ring the Bureau of M eteorology in your State. There will be a location somew here in your area record ing weather details. Evaporation data is

40

WATERWORKS DECEMBER 2001


TH E

WASTEWAliER

EQUATION

Muddy Creek Wastewater Management Facility

Figure 1. Samele Sereadsheet

2000

2001

JAN

JUNE JULY AUG SEPT OCT NOV DEC

FEB MAR APRil. MAY JUNE Totals

UNITS EVAPORATION RAINFALL

mm mm

30.8 41.3

o.sc

PAN COEFFICIENT

36.6 44.7 0.80

46.2 42.3 0.80

68.7 109.2

160 202.5

244

67.7

90

10.7

46.7

0.8(

0.8(

51.3 0.80

0.80

0.80

172 176.3

94.3

51.5

30.8

1,392

18

32.8

46.8

39.5

570

0.80

0.8(

0.80

o.sc

80 0.80

ML

136.57 141.3( 9 1.36 77.68 53.14 34.9f 27. 18 106.00 134.63 133.90

171.82 172.47 130.33

!LAGOON SURFAC AREA UTILISED

Ha.

13.56 13.5f 13.56 13.5f 13.56 13.5f 13.56 13.56 13.5f 13.56

13.56 13.51 13.56

NVr EVAPORATIVE LOSS

ML

-3.60

IINn .ow VOLUME

ML

38.45 39.87 43.75 42.68 45.14 44.79 38.85 40.52 42.62 39.87

TNlTI.U. STORAGE AVAILABLE

-2.34 -0.72

0.5(

2.67

5.15 20.52 20.14

7.81 16.68

-2.02

73.6(;

35.13 42.75 38.00

493.96 210.83

5.78 -0.7f

RRIGATION VOLUME (our site)

ML

0.00

0.00

0.00 10.68 2 1.43 22.03 47.80 23.7(

35.19 30.00

20.00

0.00

0.00

OFF-SITE IRRIGATION (Joe's Farm)

ML

0.00

0.00

12.63 10.00

0.00

0.00

o.oc

69.83

DISCHARGE TO MUDDY CREEK

ML

o.oc o.oc

0.00 10.00 30.0C

130.00

PREDICTED STORAGE

ML ML

ACrtJAL STORAGE Notes:

0.00 11.55 12.16

30.00 30.0C 30.00

o.oc

0.00

3.60 19.8S 0.00

o.oc

0.00

0.00

97.78 88.72 76.89 76. 17 72.03 68.15 103.63 129.2( 147.64 150.7

141.37 107.86 97.85

100,68 91.36 77.68 81.52 73.6C 70.56 106.0C 134.63 133.90

I. Values for Evaporation and Rainfall as recorded from (whclever you get the data) 2. Inflow volume recorded from the totalised inflow meter al the plant 3. Irrigation volumes to our site are as recorded on the meter (irrigation pump, water wheel etc). 4.Off-site Irrigation volumes to Joe's site arc as recorded on the meter (irrigation pump, water wheel etc).

5. Discharge off-site to (Muddy Creek) as per outflow meter. 6.Actual Storage Volume is calculated at the end of each month for comparison with the Predicted Storage Volume. 7. Figures arc accurate to the end of each month where an actual storage value has been entered. 8. Colours Used in model : Unshaded reserved for values calculated by the model. Blue or mauve is used for fields requiring the operator to input raw data.

li mited and you need to fin d a site with similar characteristics to you r plant. Alternatively, collect your own data on site w ith a calibrated rainfall gauge and evaporation pan. T his will give m uch better data and is inexpensive to set up. Pan Co-efficient

Pa n co-efficien t is necessaty to allow determ ination of net water loss or gain fro m the ponds due to evaporation and ra infall. Evaporation of water fro m the surface of a water body is a fu nction of a nu mber of facto rs affec ted by the surface area. An evaporation pan has a small surface area and , as air passes quickly over the pan, it is not likely to becom e saturated with water vapour. Lagoons are much bigger and air passing over them may become sa turated by water vapour by the time it has travelled only part of the distance over the lagoon. Thus, the volume of water evaporated from a pan may be higher than for a larger water body such as a lagoon . Most literature suggest a uniform monthly pan coefficient of80%, although in windy, inland or arid regions, it is possible for the co-efficient to be much higher due to the drier air. Initial storage available

To start the model, we reqmre the actual storage volume, as measured on the last day of the previous month. Each

m onth, the operator manually replaces the predicted storage at the start of the next m onth with the 'Actual' storage at the end of the previous month. To ob tain consisten t 'actual' storage da ta, some type of permanent marker system needs to be installed into each lagoo n fro m which the water level can be recorded. Graduated depth m arkers can be attached to structures or to posts driven into the banks, or even flow distribution pits. T he top (zero value) of the marker must coinc ide w ith the top of the lagoon emban kment. If the top of a pit is chosen as the 1neasuring point, the level of the pit above or below the top of ban k m ust be determined. This allows a measurement to be recorded even if the lagoon has been filled slightly above its design freeboard limit. Record the water level weekly with the measurem ent taken from the same point each time. A spreadsheet can be developed to calculate storage available. To do this we need: • lagoon surface area (average), • design or required freeboard, • heigh t above freeboa rd level to the top of the marker point or bank, and • actual depth to water from the m arker point. Surface area is required in hectares and all levels in millimetres.

Assu ming that the measuring points are set to be level with the top of the lagoon embankment, use the following fo rmula to determin e sto rage available: Storage Avail (ML) = (D epth to water required free board [mm]) x Su rface area/0.01 (ha) If the result is positive then there is capacity ava ilable fo r m ore water, if it is negative then the lagoon has been fill ed above its design freeboard level and steps should be taken to reduce the water level. A descriptio n of how to determin e average surface area is included below. Lagoon surface area utilised

The lagoon surface area (average) utilised is necessa1y to allow determination of net gain or loss of wa ter in the ponds due co rainfall and evaporation. U ndertake survey o f the lagoons to determine average surface area. Use a measu ring wheel or tape to determine the length and width of the lagoon banks at the top . Lagoons are usually constructed with batters of 3: 1 and unless the banks are very steep, assume this value. Measure the average water depth in the pond by using a boat and measuring stick to determine the water depth at a num ber of points in the pond on a unifor m grid pattern. Around 16 locations for a lagoon of approx 4ha in area should be enough. WATERWORKS DECEMBER 2001

41


TH E

WASTEWATER

T hese depths establish whether the floor of the pond is level and allow an average depth to be calculated fo r use in the su rface area calculation . M easure the air space between the current w ater level and the cop of the lagoon bank to give an overall depth . Attempt co pick the lowest point of the bank for this measurem ent, as this is where the p ond would overtop fi rst if overfilled. Assuming a pond is 50111 long and 30111 wide at the top , and the average depth of water the day it was surveyed was 1.6111 plus 0.4111 from water level to top of bank, giving an overall depth of 2111. Base Length = Surface length - 2 x (Depth x Slope)

= 50 = 50 -

2 ( 2 X 3)

12 = 38111

T herefore Average Len gth Base Width

= (50 + 38)/2 = 44111.

= Surface width - 2 x (Depth

x Slope)

= 30 - 2 ( 2 X 3) = 30-12 = 18111 Therefore Average Width = (30 Average Surface Area

+ 18)/2 = 24111.

= Ave Length x Ave width = 44m

x 24m

= 1,056 m2 or 1 .056 ha Assu me that the design freeboard 1s 0 .3111. T o determine the average usable volum e of th is lagoon : 1.056ha x 1.7111

r

i ) A

111

o,s .&

/~ING

Net evaporative loss

T his is a calculation performed by the

The Water Industry Training Centre Pty Ltd was established in Ju ne

.....,,._

~

deep = 1.79 M L. T he depth used in calculating the volum e is 1. 7111 as this is working depth caking into account the desired freeboard. It is possible to fill the lagoon to 2111, which would take the overall capacity of the lagoon to 2 .112ML but it is undesirable operationally. For odd shaped lagoons the best approach to determine average surface area is to dissect the lengths and widths to form squares, rectangles or triangles wherever possible. T he area of squares and rectangles can be calculated relatively easily as above. Average surface area applies when the lagoons are exactly half full . The m argin fo r error as the ponds fill or emp ty is usually not excessive and therefore we do not need to adjust the average surface area of the ponds in the model as we update it. T he exception to this is w hen lagoons are taken totally offiine for works or are emptied completely, as this will impact on overall evaporation area. Remove the area of these lagoons from the model and add again once they are refilled.

yi

~ (,,~

~~~;i:~0~0itt~~~~~: for

water and was tewater treatment plant operators, previo usly provided by the Water Trai ning Centre for over 20 years .

~

The Centre is a Regis tered Training Organisation with authority to de li ver training and award the fo llowing Certifi cates from the National Water Indu stry Training Package• • •

Certifi cate 11 in Water Industry Operations Certifi cate 111 in Water Indus try Operations Certificate 1 V in Water Indus try Operations

The Centre provides a range of training modules with several delivery modes:- off-the-job, distance learning and a combi na tion of these two. Modules can be tailo red to meet local needs and are available on-site or regionall y. A Schedule of modules offered at the Centre is available together with full details of the Na tio nal Water Industry Training Package.

Water Industry Training Centre Pty Ltd C/· Deakin University P.O. Box 593, Belmont, Vic. 3216 Tel: (03) 52 440800 42

WATERWORKS DECEMBER 20 0 1

model caking into accou nt pan evaporation, rainfall, pan coefficient and lagoon surface area. T he model calculates net loss or gain of water at the plant in m egalitres. Inflow vol ume

This is the m.onthly total of raw waste entering the plan t and is essential for any plant. Some form of raw waste metering is usually required in the W M F's EPA License. Normally only monthly totals are required , except for special updates. Irrigation volume

In ou r example, there are two areas utilising reclaimed water from the plant for irrigation. The fi rst is 'our site' which is land owned , operated and irrigated by staff fro m th e Muddy Creek Water Au thority. T he second is 'off-site reuse' on a neighbouring property - 'Joe's', with volu mes applied to both sites recorded by flow meters. Discharge volume

Surplus reclaimed water not able to be irrigated can be discharged to the Muddy Creek u nder an E PA License. T he volume discharged is recorded by a flow meter. In this case the daily discharge li mit is lML. Predicted storage

\tlDUs,-A -L~

EQUATION

At the end of each month, the net inflow and outflow volumes are calculated taking into account the initial storage capacity available . T he model th en predicts the volume of storage capacity likely to be available at the end of the mon th. Actual storage

This is calculated by physically measuring the water depth in each pond as described earli er. T he 'actual' storage volu me is entered into the model and com pared with the 'predicted' volume. This value can be used to indicate that all data to the end of this particular month are accu rate - fo r the rest of the year, where there is no value in the 'Actual storage' step, all values are understood to be predicted. Balance figure

T here will be a difference between the 'Predicted' and 'Actual' storage volume on a monthly basis. Any discrepancies plus or minus 10% should be immediately investigated. Items likely to cause a discrepancy include fa ults due to the accuracy o f data such as the actual storage capaci ty measured; the calculated surface area or evaporation volume; isolated or locally


THE

WASTEWA'IER

heavy ram events not recorded at the weather m onito ring site; problems with flow meters etc.

Interpreting the data and results It is necessary to enter average inflow and outflow figures into ALL fields in the model when attempting to predict future ba lances. Inflow and outflow volumes should be readily available at all plants, therefore the only difficult data to source are likely to be rainfall and evaporation. If long term reliable flo w data aren't available, ent er actual valu es fr om inu11ediate past months and estimate values for th e remainder of the current year. T he Bureau of Meteorology should be able to supply weather data fo r a site with a climate similar to yours. If data for are not available, use the next closest data to get you started and consider setting up yo ur own pan. As th e model is updated with actual data each month, it becomes progressively more accu rate. In the absence of long term data, actual figures from this year can be entered as predicted figures for next year. The model can be used to provide data on 'what if scenarios. It is possible to check th e impact of certain events by altering th e values in a row of the mo del and then looking at overa!J effects. Some examples of how you might use the model are: • Assume we are experiencing a rea!Jy wet year. By entering 90th percentile data for rainfall and evaporation (instead of average data), we can review the ]jkely impacts on balances if th e weather is wee for the rest of the year. Alternatively, it is possible to check o n the availability of reclaimed water for irrigation on a monthly basis in a dry year. Entering higher evaporation and irrigation demand, coupled with lower rainfall, may indi cate w hether rationing of reclaimed water for irrigation wi!J be required. • Assume we want to take a lagoon off lin e and empty to do some work in it. Once empty, reduce the total lagoon smface area and the initial storage available by the area and volume of the p ond off line. This allows us to see how long the pond can stay off-line to allow the works to be completed, and when or if we need to discharge due to reduced storage capacity. • Assume that a new industry wants to start up in town. Add their predicted efiluen t volume to the monthly inflow figu res and, leaving all other facto rs the same, see w hat impact this has. The model indicates the need for more irrigation

EQUATION

areas, increased discharge, or more storage ponds. Alternatively it might demonstrate that in normal years we can handle the extra volume. • Assume that we have lots of Blue-green algae in o ur lagoons and it is too wet to irrigate. If we estimate how much we could possibly irrigate for the rest of the season (which may be none), the model indicates how much storage room is left and the latest date to start discharges. This inform ation may be important in determining the most appropriate cou rse of action chosen to lower the algal levels. As demonstrated, entering data to cover various scenarios alerts the plant operator to the possibility of future events and the operator can then develop necessary contingency plans well in advance

Further refinement development of target draw down curves Once data from a few years have been collected , the operator can easily develop a target draw down cu rve for the WMF. This curve alerts operators to minimu m and maximum volumes of water that

should be retained within the lagoons o n a monthly basis. After updating the mass balance model, the operator can check the available storage aga inst th e target curve. This w ill indicate if there is m ore or less water in the lagoo ns than normal. Appropriate site management decisions can then be made. U se of a simple m odel such as this is a step forward in allowing WMF operators to adopt pro-active management systems at their plants. This type of model has been successfu!Jy operated at a numb er o f Goulburn Valley Water WMF's for many years an d is being introduced as a standard management tool for alJ plants. Two versions of the spreadsheet model can be downloaded from the Australian W ater and Wastewater Operator's Association (A WWOA) we bsite at www.awwoa.org.au. - an Excel 5.0/95 and Excel 97 /2000 workbook depending on what computer system you use. Copy the blank model and then modify it to suit your own WMF by adding or deleting rows. If you have any queries on the operatio n of the model send me a note at waterbalance@aww·oa.org.au and l'IJ try to help you out. Good luck and good balancing !!!

KSB GJ

All new

Forrers

proud l y manufactured in Austra l ia

Pumps Mixers Service Victoria: (03) 9314 0611 New South Wales: (02) 9584 2099 Queensland: (07) 3282 1766 South Australia: (08) 8234 0066 Western Australia: (08 ) 9455 7900 New Zealand: (09) 634 4020 Email: ksbcentra@ksbajax.com.au Website: www.ksbajax.com.au

KSB Ajax Pumps Pty Ltd WATERWORKS DECEMBER 2001

43


SEWAGE

T R EA t MENT

PLANT

UPGRADING THE MORWELL SEWAGE TREATMENT PLANT Mick Cook, Gippsland JiVciter Operator The Morwell Sewage Treatment Plant (STP) consists of 2 separate extended aeration plants. Each plant has an aeration basin with 2 low speed aerators, a circular clarifier (see Fig. 1), RAS and WAS pumps. There is a common raw sewage feed via 2 Archimedean screw pumps. South plant has a larger basin (2 130 111 3) than North plant (1313 1113) with both having the same size clarifiers. Both clarifiers discharge into a common lagoon system which discharges to the Morwell River. At present a new UV disinfection system is being installed on the plant discharge, at which point the lagoon system as it now stands will be decommissioned, keeping two fo r sludge lagoons and two for emergency storage (Fig 5). T he problems faced at the plant over the last 5 years and the solutions to the problems are described below.

North

M orwe ll STP - Ortho Pho s ph ate - 1998

• South

~ ji ffiIII flj~j.:JJi.......................l 11

Aug

Sep

111 Oct

Nov

Dec

Dec

Jan

Jan

Graph 1 . Phosphorous levels in the effluent from the Morwell STP before and after

the introduction of PFS to the raw sewage. Solution

• Dosing of raw sewage with Poly Ferric Sulphate (PFS) for P removal. • pH correction using caustic. The caustic is dosed after the PFS. • Installation of a new UV disinfection unit on Figure 1 . Activated Sludge Plant overview. the eilluent from the meters before the caustic injection . The clarifiers to eliminate the lagoons from the Problem No 1 - High solution to the lagoon problems involved normal process and allow discharge Phosphorous a longer time frame and at the writing of directly into Morwell River. The EPA discharge licence requires a this report the UV disinfection unit was • Set up 2 lagoons for emergency storage median total phosphorous (T-P) of ready for commissioning. almost in the event of plant breakdowns or high 0.5mg/L and a 90th percentile of 1 mg/L. turbidity. The lagoon effluent can be Results There was no dedicated removal of pumped back to head of plant. • P levels at the discharge of the clarifiers phosphorous from the raw sewage other • After a substantial on-site trial period now average 0.5 mg/ L, fluctuating than what normally occurred in the using temporary equipment supplied by between 0.3 - 0.6 mg/L (see graph below) conversion of food to biomass within the Aluminates Chemical Industries, the • The effluent from the south clarifier is activated sludge plants. The N and S required P results were ac hi eved. slightly more turbid than the effluent from clarifier effluent T-P's were 5 mg/ L with Aluminates were commissioned to install the north clarifier. The turbidity is due final discharge from the lagoon system to a permanent dosing facility of lx 10,000 to ferric hydroxide/ferric phosphate floe, the Morwell River ranging from 5 - 9 litre PFS tank, lx 10,000L Caustic tank resulting in the P level from the south mg/L. The increase through the lagoon and variable speed diaphragm pumps with clarifier being 0.1- 0.2 mg/L higher. Both system was attributed to P release from the PFS pump flow paced to inflow and plants are fed common raw sewage, dosed the anaerobic sludge layer in the lagoons. Caustic pump controlled by an in-situ pH with PFS at 180 mL/kL, so we are Further to this, the lagoon system was meter in the south basin. Due to physical currently looking into areas where floe prese nting major blue gree n algae constraints the PFS injection point was problems in relatio n to the E. P .A. shearing may occur such as the RAS mounted in the inlet channel only 4 licence. pumps and check valves. The RAS flow rates in the south plant are higher than those from the north plant due to llorwell lTI' • Turbldlly • 1111 clarifier design and intermittent operation (explained later). ao ++~=-----,c~;___i1.---==.:...:::::;;::.:.:::..;===:.::.::.:.:.::::::.:::::.:!------~ • There were doubts as to the position ; 111 of the PFS injection point providing a 10 t--------...:;_~'\---P.~L-~t----::.....-JAt,,;a;..;::lloc....d good mixing zone so it has been relocated ll t----------....ljt-------=:...i.-,--------=i further upstream before the screw pumps, Jul Jul Jul Jul Jun Jun to aid mixing. • Flow pacing of the variable speed PFS Graph 2 . Turbidity in the clarifier effluent from t he Morwell STP before and after pump has not been as accurate as desired, modifications t o the operation of the influent screw pumps.

aa-li=:.=====:::::;;;~============================~

...,

44

WATERWORKS DECEMBER 2001


SEWAGE

due to the inability of the pump to cover the f.low range adequately e.g. @ 20 Lisee = 225 mL/kL, @ 40 Lisee = 135 mL/kL. A new, more accurate pulse pu mp 1s currently being installed.

Problem No 2 • Hydraulic overload of clarifiers Initially there were two Arch imedean screw pumps with one on duty and o ne on standby . T hey were controll ed by a muJtitrode level sensor wh ich allowed the pum p well to fill to TWL before the p u m p operated, at w hi ch point it delivered approxi mately 200 Lisee (17000 3 111 /d) . This caused hydraulic overloading of both clarifiers resulting in solids washover. Solution

Operate the duty pump on continuous manual run to el imi nate th e bu ild-up of raw sewage in the pump well and remove the associated hydraulic peaks to th e north and south plan ts. Results

Solids wash-over from the north and south clarifiers is now not an issue resulting in higher quality effluent (Graph 2).

Problem No 3 · More accurate control over aeration to achieve consistent N removal The north and sou th basin aerators were controlled by timers so that the two aera tors in each basin were co nnected to a co nunon timer and operated intermittently to achieve conversion of foo d to biomass and Nitrogen removal. The EPA licence req uires ammonia reduction to 2mg/L m edian (5mg/L maximum), and nitrate to a level so as not to exceed a T otal Nitrogen level of 10 mg/ L. W ith no dedicated m ixing zone for denitrification and the chan ce of under or over aerating du e to varying o rganic loading over a 24 hr period, it was very difficult to reach and sustain the above requirements given the restriction of m a nu al l y set t imer operation. Solution

Install a D.O. sensor on each o utl et ae rator for automatic control via the plant PLC to achieve food conversion and nitrification (ammonia removal) whilst

TREATMENT

PLANT

Morwell STP • South Clarifier· 1111111

t

N03 --NH4

12 10 8 6 4

2 0 Feb

Feb

Mar

Apr

May

Morwell STP • North Clarifier 19911

Jun

Jul

Jul

Aug

Sep

Ocl

N03 --NH4

20 - , - - - - - - - - - - - - - - - - - - - - - - - - - - - - - , 15

110

5 .

outlel aerator changed from 1,mer to 0.0. sensor I PLC conlrol

-i

0 .jJ..:~~~~~i,,,...l~..CW:.M~~l,lQ~QQll,4\j~~-~,...Q,~~-1,,11,,,~

Graphs 3 and 4. Ammonia and Nitrate levels in the effluent from the north and south clarifiers showing the effect of the modified aeration controls.

l eaving eac h in le t aerator operating intermitt ently via ti mers (4 min on 40 min off). Th e int e rmittent operation of the inl et aerator creates a denitrifica tion zone (re fer Figure 2) where raw sewerage is mixed with th e biomass th ereb y encouragin g ni trate reduction. Result

Figure 2. Intermittent aerator/mixer in foreground.

T he modifications to the DO and mixing con trol has stabilised N removal at the plant, with ammonia and nitrogen levels staying well within licence limits (Graphs 3 and 4) . H owever, given that the bulk of nitrification/denitrifi cation is occurring at opposite ends of the basin (excepting sim ultaneous nitrifica tion/ denitrification in the nitrification

zone) it doesn 't take much of a shift in operating parameters to upset the balance. There is still work to be done to trim up the process in this area to reduce so me of the ammonia/nitrate peaks as shown in the graphs and thereby ach ieve more reliable ope ration. Furth er areas to consider are: • Dete rmi ning the most effective position for the D.O sensor in regards to distance from the aerator and depth under the surface. At the moment the D .O . probe is surface mounted and is approx. 8 meters from the edge of the aerator impeller. The intention is to move closer to the aerator (approx 3 metres from edge of imp eller) and deeper under the surface (approx. 2.5 metres/1 metre from the bottom). Hopefu ll y this position will result in more sensitive con tro l over Figure 3 . Splitter-box (foreground) and screw pumps and inlet works (rear). anunonia/nitrate removal by WATERWORKS DECEMBER 2001

4S


T R EATMEN t

SEWAGE

- -North

Morwell STP -Mixed Liquor Su1pended Sollda -1999

- - South

6000 5000 4000

't

3000 2000 1000 0 Mey

Jun

Jun

Aug

Jul

Sep

Aug

Nov

Oct

Dec

Graph 5. St abil isation of MLSS in the north and south basins after commissioning of the f low splitter box.

the other. This transfer caused an imbalance in # . -~·-a:ii!f;~ . :, the mixed liquor solids _ ~ . . . ~-,c--...,. •f .. rJ . .• . as well as a drop of u p ~ !"' t o 400 111111 i n the .... .- -. . clarifier T W L. This was Figure 4. South Clarifier. caused by the north and sou th basins (both at diffe rent TWL's), being interconnected having the aerators switch off at an earlier via a co mmon raw sewage inlet pi pe. stage w hen the D.O. wou ld in dicate completion of nitrification (thus not over Solution aerating and destroying den itrification) A raw sewage flow splitter box was and switch back on earlier as D.O.'s begin constructed to isolate the north and so uth to fall. H opefully this will also save some basins from each other. The box was power usage. constructed so that a choice of splits was • Style of 0 .0. probe. At this stage available e.g. 50/50 or 60/ 40. Th e design also included an overflow weir to membrane style probes are used and in o ur application they seem to requi re re-direct flows in excess of 6 M L to the regular cleaning (1/ week) and calibration lagoon system (see Fig. 3) thereby elimi(1/mth). Biom ass adheres to the surface nating hydraulic overload of the activated o f the membrane and if not rem oved, it sludge plant. begins to affect the performance of the membrane. A Zullig probe with a mo tor d rive n grin d stone w ill be trailed to see if it can provide more accurate results over longer m aintenance intervals ly· pau (s upposedly 1/yr other than occasional visual inspection). • Trial a VSD on the inlet aerators in the de-nitrification zone to slow down the speed to 15 - 45 rp m , thereby reducing the 0.0. input and To Morw1II River increasing their potential as a U,Y,,.__ _ _ _,. contin uous mixer/ stirrer. lludg1 ....... :UML U•L The fi nal speed is very H mL much dependent o n the gearbox design of the aerators lludg1 ....... e.g. the north aerator has oil H mL ( 1tandby) immersed gears and can turn down to 5 rpm, while the To pl a nt Inlet Horw,11 , 1:!Uutnt Pete sou th aerato r has oil pump ( ) • Stand, DIV, Horwen · Aeu1tlon1I Pecernes:ece lubrication and can only turn SRT • 21 d1Yt COD • no (110) mg/I down to 15 rpm. NHS • 34 (10) mg / I MLII • SOOO mg/ I

.~ ·-· - --=

~'\

. '" .

- - - - - -·

- - -

---;--~ ,

-

¥

••

.•I

' __ - -

_,.;_

· - · - - -

.

!. ,-'-!-:o, · · --~

_

...--

PLANT

Result

As a result of these changes the clarifier water levels do not flu ctuate relative co each other, solids transfer has stopped and the M LSS in the basins has stabilised (Graph 5). T he high flow bypass has also assisted in reducing clari fie r turbidity levels during periods of high rainfall.

Problem No 5 • Poor removal of sludge from south clarifier Settled sludge in the bottom of the south clarifier was not being removed uniformly due to the suction tubes in the clarifie r bridge (see Fig. 4) block ing off w hen a lower flow rate was selected. Solution

T he RAS pu mp rate was changed from a continuous 11 L /sec (950 kL/ d), to intermittent p u mping by reconfiguring the existing timers and setting them at 20 min off/6 min on. This setting still achieved the required 950 kL/ d over 24 h rs , but when operating, the p u mp delivers 29 L /sec thus keeping the suction tubes fl ushed clea n. Results

Sludge is now removed in a u niform manner across the fu ll w idth o f the clarifier floo r. However, the ti mer controlled metho d will not be long term, since during the R AS pump operating period there is a flow surge created by the higher return rate to the south basin and back to the clarifier. To overcom.e this, the intention is to program the PLC to ramp the VSD up to a maximum flow rate of29 L /sec but for only 30 seconds and at 30 min intervals, thus elim.inating the extra surging.

........, ......

TP04 • 7,5

Problem No 4 · Stabilisation of solids in aeration basins During perio ds oflow flow there was a partial transfer of the contents from one basin to

46

WATERWORKS DECEMBER 2001

RAI • 111 (Qr I QI) ~- (Pn) • 170 mL/kl

(1,S)mg / I

~

IOD mg/ I II mg/I NHS mg/I

10 15

15

Toi.I N mg/I TP04 mg/ I

10 0,5

15

so 5

Figure 5. Morwell Plant Layout with t he U.V. unit operating.

Author Mick Cook (cookm.@ gippswater.com.au) is a sewage treatment plant operator with Gippsland Water. He has operated the Morwell STP for 3 112 years. Prior to joining Gippsland Water, Mick worked at a n umber of South East Water STP's. Acknowledgements T he plant upgrade changes have invo lved Ruth Knight (previo us operator), D r Peter Mosse, D r J o h n Messenger (CMP S&F) and J ohn Smith (CMPS&F).


PARTICLE

PRACTICAL EXPERIENCES WITH PARTICLE COUNTERS Michelle Colwell - Jifiater Treatment Technologist, Gippsland Jifiater Particle counters are useful tools for optimising and mon itoring the overall performance of treatment plants. H owever, their usefu lness depends upon ca reful maintenance, correct set-up, and being aware of their limitations. This article provides an insight into some of the exciting things that can be done with particle counters, but also details some of the operational difficulties that m ay be encountered when using particle counters, and offers some adv ice on how to overcome these problems. Further, this article wi!J explain in practical terms, how to use the information provided by a particle cou nter to optimise fi ltration performance. What is a Particle Counter?

Conventional water treatment reli es upon t u rbidity m eas u rements to determine how well filters are performing. While turbidity measurements are useful, the info rmation received from a turbidity meter is limited. A turbidity meter can tell yo u how ' cloudy' the water is, but it can't tell you whether the 'cloudiness' is ca used by lots of smalJ particles, a few large particles, or any combination of the two. A particle counter is an instrument that can measu re both the number of and size of particles in a water sample. A laser beam passes through the water sample, and the 'shadow' cast by particles in the sample fulls onto a sensor. Each 'shadow' is counted, and the size of the 'shadow' is directly related to the size of the pa1ticle. Particle counters are therefore more versatile tools for monitoring filtration performance than turbidity meters. Th e particle co un t ers u sed by Gippsland Water have been configured co measure the total number of particles

in the 2- lSµm size range in the filtered water. By measuri ng this size range, we can cou nt particles the sam e size as Cryptosporidi11rn (4-6µm ) and Ciardia (812µ 111) 1. Cryptosporidi,1111 and Ciardia are both protozoan (single celled animal) pathogens that are extremely resistant to conventio nal meth ods of disinfection. Th ey are capable of ca using moderate to severe gastrointestinal illnesses. Filtration provides a physical barrier, which is the most effective way to red uce the risk of these organisms entering the reticulation where they may cause disease. Log reduction

Log reducti o n is a term often used w hen descri bing the effectiveness of a WTP in removing particles. However, given that many raw waters have relatively low particle counts to begin with (less than 20,000 particles/ml in the 2-1 Sµ m size range), and measuring particle counts in raw water can be difficu lt and u nreliable, measuring log reductions does not give a true indicator of the fi.lter's perfo rmance. Achieving a good log redu ction is dependant upon high raw water counts, and takes no account of the actual q uality of the water exiting the filters. A particle counter will generate real time particle count informa tion on the actual particle cou nts exiting a filter, and these are a more reliable indica tor of filtratio n performance. Gippsland Water aims co achieve less than 200 particles/ml (in the 2-l Sµm size range) for 95% of the time. 2 U sing actual particle co unts requires no complex mathematics. H owever, for the mathematically inclined, the following formula can be used co calculate a log removal.

Table 1. Comparison of log reduction and absolute counts (all figures are

counts/ml in t he 2-15µ m size range) Raw wate r counts

FIitered water counts

Log Reduction

Rank based on log reduction

Rank based on outlet counts

3

Filter 1

1,000,000

100

4

1

Filter 2

20,000

95

2.3

2

2

Filter 3

10,000

100

2

3

3

Filter 4

7,000

80

1.9

4

1

Log reduction

= -logrn (Filtered

wacer particle count) (Raw water particle count)

Example

Particle count exiting Filter 4 (Filtered water particle count) = 80 counts/ml Raw water particle count= 7,000 counts/111.l Using fo rmula, Log reduction = - logi 0 (80/7000) = -log 10 (0.011)

= -(-l.942) = 1.942 = 1.9

Table 1 ill ustrates t he proble m s associated with reporting log red uctions versus absolute counts exjcing a filter. The table illustrates that although Fil ter 4 is produ cing the best quality water, it is the worst performer with respect to lo g removal of particles. When using a particle counter to optimise perfo rmance, the lower the particle co unt achieved, the better the quality of water being produced.

How to use the Particle Counter to Improve Filtration Performance With common sense, and a methodical approach, significant improvements co the particle co u nts exiting the fil ters can be ach ieved. Patience and self-control is required to achieve these results, but the process is cha.llenging and exciting, and the outcomes are intensely rewarding and satisfying. Record Initial Conditions

Once jar testing has been used to detennine an optimal chemical dosing regime, the particle counter should be left to monitor existing conditions. Without chis preliminary information, you will never be able co cell whether any changes you have made have improved o r adversely affected the overall operation of the filter. Several stop/start sequences, various plant run times and several backwas hing sequen ces sh o uld be observed. It is important to record all chemical dose rates, backwash times, filter run times and plant stop/start trigger levels. Do not attempt to make any changes to your plant without first gaining this prelimina1y information. Figure 1 illustrates a typical particle count WATERWORKS DECEMBER 2001

47


PARTICLE

COUNlERS

normal backwashing (on profile prior to making any ~ ,n~I, time) should be inhibited. operatio nal c han ges . ilter Plant shutdown on filter I I Notice th e ve ry high II a,dSecc n~a~I 100 0 ' \V "" Cf outlet turbidity or head loss !"d l econda ,,IY Fllter I particle counts occurring I " ~000 I sh ould be activated t o whe n a prima ry and ----il '3000 pr eve nt t urbid water seconda1y filter come back carrying thro ugh to the 2000 - I Pia tonon line after a backwash. I \ reticulation. Carefu l T hese particle counts are J: d I Ji.. .i I .. planning is also required in ~ orders of magnitud e E::=tg g g : g 8 8 8 8 order to ensure that any g greater than the counts ;,; ~ ,!; ,!; ~ ~ ~ ~ = tu rbid water exiting the i!lg ~ ~ ~ ~ experienced during nonnal ~ ~ ~ ~ filters is disposed of to operation, and attem.pts waste, and not to the reticshould be made to signif- Figure 1. Particle counts/ml in the 2-15µm-s ize range before making operational changes. ulation , where it may pose icantly reduce or eliminate a health threat to consumers. these particle p eaks, in plant. Simple mathematics is required to Experience indicates that it is often order to achieve the target ofless than 200 calculate the following: difficult to effectively dump water, as particles/ml in the 2-15µm-size range, for existing control mechanisms and flow • The capacity of your backwash tank(s) 95% of the time. paths are generally not designed to cater • The capacity of your sludge handling Start by using gross visual means to for this kind of activity. facilities optimise plant performance • T he backwash rate(s) Compromises may be required The first thing to check is wheth er • The supernatant return rate Once a filter has been allowed to your filters are cleaning up effectively Once these figures are understood for proceed to particle breakthrough, you during backwashing. Watch and time each component of the plant, you know several backwashes under existing condimay fi nd that a single backwash is insufthe boundaries that you are working ficient to clean it effectively. If this occurs, tions. Record your observations, and also w ithin. E ntering informatio n into a record backwash rates by measuring the the filter should be backwashed again until spreadsheet is a useful way to represent rise rate of water in the filter du ring is comes clean, and a reduced maximum this information. For example, if your backwashing. A plot of level versus time filter run time should be estimated based backwash tank capacity is 25000L and the will allow you to calculate backwash rates. on the plant's ability to clean the filter in backwash rate is 1501/s, then you know a single backwash. You will find that Your observations may indicate a need that the maximum time that you can compromises such as this are required in to increase or decrease either the backwash backwash your filters is 2.75 minutes. rate or duration. Exercise caution if order to produce the highest quality water. Similarly, if the supernatant return rate is changing the backwash rate, as the rate Do not be ove rly su rprised if the 4 1/s, then it is going to take just over an must be high eno ugh to fluidise the bed, operating conditions that you eventually ho ur and a half to empty the sludge but not so high as to risk media loss over decide upon are far removed from the handling facility if you backwash for 2 .75 the launders. A long handled rake inserted original design chara cteristics of th e minutes, so you will have to w ait at least into the sand bed during a backwash w ill plant. Achieving design capacity may also this long before backwashing again. give a good indication of whether the bed be difficult, given that backwashing may Depending upon the quality of water is fluidising. If the rake does not fall to either consume more water, take longer entering you r plant, you may or may not the bottom of the filter under its own to complete, or be more frequent than be able to wait this Long before another weight (but remember to hold onto the before. Running at lower flow rates will backwash is required. You must underhandle!), then the bed is not effectively also impact the plant's capacity to produce stand these physical limitations before you fluidising . the maximu m amount of water, especially make any changes to the process. Without If you decide to make changes, it is if the plant already runs for extended this knowledge, the process or the fil ters important to make only one change at a periods of time each day. could be affected detrimentally, and it may time, and WAIT and use the particle Be patient - Eradicate or minimise take some time to recover. counter to observe the effects of each rapid flow changes If yo u already have filter ou tlet change. Compare the results after making It is really important to make only one turbidity trended at your plant, you should a change w ith previous res ults to change at a time, and make small changes. have an idea of w hen filter ou tlet determine w hether the cha nge has Use common sense to determine where turbidity begins to rise. This has tradi improved the filtered water quality. the 'big wins' are likely to be. If you make tionally been the trigger for backwashing. Determine the maximum run time of changes, carefully note down the date and H owever, particle breakthrough occurs your filters time of the change, then sit back and wait, BEFORE tu rbidity brea kthrough. It • How long can your filter run before and watch the trends to see what they tell makes sense therefore to determine when particle breakthrough occurs? you. Don't be tempted to 'fiddle' and particle breakthrough begins to occur, and make other changes at the plant until at • Can you still backwash the filter effecinitiate backwashes just prior to this. If you least two complete filtration cycles have tively if the filter reaches breakthrough? do not have filter outlet turbidity trended, elapsed. A filtration cycle is the time from To determine the answers to these or the filter outlet turbidity trend does not one backwash to the next of all filters questions (under relatively stable raw show a characteristic breakthrough curve, under normal operating conditions. wate r co nditions) requires patience, then 'pushing the limits' is required. To When the particle counts exiting the simple mathematics, and the discipline not do this without introducing confounding filter suddenly increase, the filter is said to alter more than one parameter at a time. variables requires careful coordination. to be 'shedding' particles. M ost particle Ideally, the plant should be allowed to run You w ill need to understand the shedding events are likely to be attributed uninterrupted for as long as possible, and physical limitations of your treatment . -LC- •

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WATERWORKS DECEMBER 2001

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PARTIC L: E

COUNTERS

to rapid changes in flow, controlled in an attempt to ~ Plan star - Fllt11~ -~ ml S>1 1 . and the most dramatic ~-P' ak < 200 fine tune the performance Filte 2 - min: , 10 , pe, k < 1 c h an ges in flow occur of the plant. Once again , Fi,er1 ~ack ~ash 4 n ns> ~oo. oak MO during plant start up , w hen I ~ 2 B ckw Uh th e minimi sat i on of 60 hydraul ic shocks, which components of the plant Filt, 2 B ckw sh 19' ~ - 4 hins 100 lneal _.,,. ca n be associated with come back on line after ,o C1 B •ckw~sh rapid changes in flow, is a backwashing, or when a ' l'-iit key driver. A signifi cant fi lter backwashes and the [\. ,._ contributor to rapid flow .. IILl.o flow through the plant does ~ \ io-' " c h anges, part i c u l a rl y not reduce accordingly. g g g g g g g g g g g g g ' g ~ '.': ;,; ::: during backwashes and If the number of plant 2MJl/99 ~,'01A plant start/stop routines is starts can be minimised, Figure 2. Particle counts/ ml in the 2-15µm size range achieved after th e speed that valves open overa ll water quality sho uld making operational changes. and close. If alterations can improve. Consider running be made to make the the plant for longer at a T he assistance of a PLC programmer transiti on from ope n to closed and vice .lower flow rate, or allow storage basin may be required to achieve proportional versa as smooth as possible, then signiflevels to fall lower than before to allow inflow red uction, and variable speed flow icant improve ments in particle counts w ill the plant to run for longer. Consider depending upon operating conditions if be seen. Slowing down the rate that valves combining these two strategies to a!Jow ramp open or close is an easy way to it does not already exist. Allowing the the plant to run continuously. achieve better water quality, but m ay plant to com e back up to fu ll production One of th e most disruptive influences require the ass i st a n ce of a PL C slowly after a filter backwash, or when the on fi ltration performance is the change in programmer, and must be done in a plant starts up fro m stopped will improve flow rate through a filter. If plant inflow manner that does not adversely affect the water quality exiting the filters. does not reduce proportionally when one other parts of the treatmen t process. or more units go off-line, then during this Fine Tuning Figure 2 below shows the particle cou nts time, the remaining in-service filters effecOnce plant run tim es, fi lter run times that were achi eved by fine-tuning the tively take more load. The fewer the and backwashing intervals and durations operation of valves at a water treatment nu mber of filters at your plant, the greater have been determined, other factors plant. Comparing th e scale of Figu res 1 the load applied to the remaining filters contributin g to particle shedding (the and 2 gives a clear indication of the during the backwash of a single unit if in crease in particle cou nts from normal magnitude of improve ment in particle flow does not reduce proportionally. operating levels) can be hunted down and coun ts that can be achieved.

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PARTICLE

Traps for the Uninitiated Before embarking upon any particle counting exercise, a number o f key points should be addressed. To avoid falling into some common traps, th e following advice is offered. Location

Correct location of the particle counter is vital in order to achi eve worthwhile results. Particle counters are generally not suited to untreated or partially trea ted waters. Raw water particle numbers are generally high , and co unting of particles in raw water is likely to be unreliable. T he reason for this is that the sensor becomes 'swamped' . For example, if dirty water enters the unit, there m ay be so many particles passing by the sensor that individual particles are unable to be distinguished. l nstead, the senso r incorrectly counts many particles as one large 'blob', effe ctively u nde res timati n g th e total nu mber of particles, and overestimating the size of the particles. Air and slime

The relati vely low flo w rates through the particle-counting unit m.ay encourage biological growths in the sample tubing and sensor. Biological growths can fall off

the sample tubing without warning and provide a misleading 'particle event' , or may contribute to poor results due to intermittent changes in flow. Partially treated water can also foul the unit, as small floes can aggregate and restri ct flow through the unit. It is therefore important to locate the unit where there is no likel ih ood of backflow or syphoning of u ntreated water. Slime growths can be controlled by backflushing the u nit w ith a weak hypochl orite solutio n. Entrapped air can also cause spu rious results , as the unit can not distinguish between air bubbles and real parti cles. Care must be taken to avoid air entering the unit, and pipework should be designed to avoid air entrapm ent. Constant head devic es supplied with som e particle co u nters ha ve breather pip es at the highest point to purge air from the system, but if not well designed, they ca n contribute to operational difficu lties such as acting like a venturi and sucking air into the system, or allowing all the flow to escape via the breather pipe. If the breather pipe is o flarger diam.eter than th e sample pipe, and th e breather pipe outlet height is h igh er than the maximum hydraulic level of the system, the system should opera te properly.

Movement

Particle counters are sensitive pieces of scientific equipment, and sho uld be treated with care. Some brands are more sensitive to movement or bumps than o thers, or 'b umping' of co mponents during cleaning. Over zealous cleaning can move internal componen ts only fractions of a millimetre, but this can significantly affect the internal calibration of som e particle counters. Flow

Another important factor contributing to unreli able results is flow. T o provide reliable results, the particle counter requ ires co nstant flow. Most units are designed to operate with flows between 70 and 100 mis/min. T o ensure constant flow through the unit , a co nstant head device should be installed. Constant head devices are generally suppli ed with the particle co u nters. Flow th rough the unit should be checked at various tim es o f day and at various stages of the filter run. Flow m eters suppli ed with some co mmercially available units can be unreliable. Manual checks with a measuring cylinder and stopwatch are essential to verify actual flow th rough the unit.

Sludge Interface Monitor The world's leading ultrason ic manufacturer, Hawk, has now developed and successfully tested a new range of sonar interface units for use in primary and secondary clarifiers, IDEL and IDEA plants as well as DAF plants and potable water clarifiers. We offer continuous level measurement of the blanket for pump control as well as monitoring the fluff layer for water quality. Point density analogue for monitoring water density changes and sonar point switch devices. We also have a portable density analyzer that can be calibrated to work in water to sludge density. All instruments are 100% Australian made and come w ith a two year warranty.

50

WATERWORKS DECEMBER 2001


PARTICLE

PARTICLE COUNTING

COUNTERS

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Maintenance

Record keeping As with alJ instruManual me nt s, a partic le A facto r vita l to cou n ter wi ll not event m o nitoring is prov i de reliable the availability of an results if it is poorly accurate record of maintained. T he unit the plane's activi ties. must be regularly To interpret the data Figure 3 . Exa mple of a particle correc tly, knowledge cleaned, either by counter with supporting software on man ually inserting a of plant activities and laptop computer. t he time chat it ta kes mi n iat ure bottlefo r th e sa m ple to brush , back flushi ng the un it or both. travel from its origi n to the sensor is vital. Periodic fl ushing with a cleaning fl uid m ay You must be able to correlate a 'particle be necessary in some cases, but it is wise even t' detected by the particle cou nter to to c heck with the manu facturer prior to an operational activity (such as a backwash) in troducing any type of ch e1ni cal cleaner at the plant . Y ou m ust be able to track into the unit. fi lter backwashes for all plant co m ponents Software and power failures (not j ust the filter you are looking at), plant stop tim es, plant start up times, and any Som eti m es the software programs chat cha nges in raw water flow or q uality . acco m pa n y the pa rt icle - cou nt i n g Wit hou t chis in formatio n, coll ectin g instru ment can cause difficulti es. If power pa rticle counts is a waste of ti me. to the co mp uter is interrupted, w hen

power is restored, often the unit will either fa il to resume data capture or capture incorrect data as pre-set flow rates and sam pl ing times have bee n replaced by defaul t settings. It is important to ensure a constant power supply to the un it to avoid these data capture proble m s. Surge protectio n of the entire un it is also hi ghl y reco mmended. Sample line layout and materials

PMS LIQUILAZ COUNTER Particle Measuri ng Systems range of water and liquid counters are today used a s primary testing standards in water treatment and related fields. Fea tures include 15-32 user definable size channels, validated software and much more.

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T he length an d layout of samp le tubing, and th e type of m aterial used for the samp le lines ca n also con tribute to poor resu lts. W here possible, sa mple cubing sho uld be as shore as poss ible to min imise hydraulic losses, and conta in lo ng sweeping bends in prefere nce to 90degree bends. T he tu b ing should also be constructed of a m ateri al chat does not have a tendency for particles co accu m ulate on internal surfaces, and then fall off the walJs without warning. It is wise to use tubing that complies with the manu facturer's recommendation. Sweeping bends mi nimise turbulence, which can cause any accumulated particles to fall off th e inte rnal walls of the sample tubing. Similarly, ho rizontal pipework is preferred over vertical pipework, as more even flow dynamics can be attained in horizontal pipework. Solenoid valves o n sample lines should also be avoided where possible, as the ir sudden action may incite a spurious particle peak due to the 'shedding' of particles that may have accumulated in the line behind the closed valve . The use of incompatible m etals in pipework and fittings should also be avoided , as even minute corrosion will be detected as particles.

Electronic The abili ty to tre nd particle counts in para ll el with o ther plant related inform ation is invaluable. A pictu re tells a tho usa nd words, and be ing able to grap hi cally rep resent p lan t flow, turbi d ity , particle cou nt, head loss, filter levels and va lve positio ns all on the one g rap h is extremely usefu l. If the pa rticle cou nter that you c hoose is likely to be a permanent installatio n , it is worth w hil e checking w hether the particle counter has the ability to sen d out a 4-20mA signal chat can be picked u p by a SCADA system . It is preferable to be able to trend al l releva nt plant i nformation o n t he one system, and the one graph, rath er than attempting to ' m arry' incompati ble software syste m s. If correctly located and m ain tained, particle cou nters are val uable m on itori ng tools to assist in t he full o pti misation of filtratio n p lant performa nce and ensure that the high est q uali ty water is produced at all ti m es.

Acknowledgements T h e assistance of D r Peter Mosse for encou raging t he concept of w riting a practical ' hands on' guide to particle counti ng and criti cally reviewing the manuscript is gracefully acknowledged.

References 1. Anon (1996) Australian Drinking Water

Guidelines. N HMRC and ARMCANZ. Commonwealth of Australia. 2. Murray, B. A. ( [995). Particle Counting in Water Treatment. Water, 22:37-40

The Author Michelle Colwell (colwellm@ gippswater.com.au) is a Water T reatment Technologist at Gippsland Water. P rior to th is s h e wo r ked as a senior M icrobiologist in the Gippsland Water laboratory. WATERWORKS DECEMBER 2001

S1


PROJECT

IMPLEMENTATION

MELBOURNE'S WESTERN TREATMENT PLANT AUGMENTATION T Schubach Abstract Melbo urn e's Western Treatment Plant, which was commissioned over a hundred years ago based on land treatment, now operates largely on huge lagoon systems and deals with an average of 500 ML/ d. An Environmental l mproven1ent Strategy to achieve nitrogen reduction has r ecent ly been developed and approved. The first stage i s the Anoxic zone 1 and 2 which houses the mixers . conversion of one pond in the SSE lagoon to a unique Proj ect planning cons id e red all activated sludge system, beyond the contra ct delivery methods and recomlimits of conventional engin ee ring mended the adoption of an Alliance practices.

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contract appro ach wi t h common incentives fo r all service providers. T his paper outlines two key components in the success of the project - the Alliance and the Process D esign Workshop.

Background The Western Treatment Plant (WTP) is the largest sewage treatment facility in Au stralia an d processes mo re t han 500 Ml of sewage a day. What makes it unique in Australia is that it discharges diluent into an enclosed bay - Port Phillip Bay. The Bay is Melbourne's most vital natural asset for economic, recrea tional and environmental reaso ns. B etween 1992 and 1996 M elbourne Water sponsored t h e CS IRO to undertake an in-depth study (Port Phillip Bay Environment Study) into the health of the Bay and found it to be "mrprisingly healthy" by world standards. It found that the nutrient inputs into the Bay from the Yarra River and its tributaries, stormwater drains and the Western T reatment Plant balanced the natural breakdown of the nutrients. H owever, the study identified that there was a danger of eutrophication if the input of nutrients were to increase. Therefore, it recommended that there should be a target reduction in the annual nitrogen load of 1000 tonnes from aII sou rces. Half of the nitrogen load entering the Bay comes from the WTP Conseq ue n tl y th e Environme nt Protection Authority (EPA), issued a revised wastewater discharge licence for the WTP. This contained more stringent effluent quality standards which will come into effect on January 1, 2005, along with an inm1ediate requirement for a 30% reduction of nitrogen by December 2001. . The amended licence also updates limits fo r a number of key characteristics of the effluent, including Ammonia


PROJECT

IMPLEMENTATION

(NH 3), Biochemical Oxygen Demand (BOD), and Total Suspended Solids (TSS). A separate but equally im p ort ant environmental factor was that the WTP also provides a haven for tens of thousands of birds and is recognised internationally as one of the world's most significant wetlands. It is listed as a 'Wetland of International Importance under the Ramsar Agreement. T his meant that any upgrades or construction work on the WTP site could Return Activated Sludge (RAS) pump station only be undertaken under the strictest environmental guidelines and practices. 1. To reduce the total amount of In o rder to meet all these challenges nitrogen discharged to less than 3500 Melbourne Water commen ced the tonnes/ year. 'Environment Improvement Project' 2. To improve diluent quality in relation (E IP). to BOD, TSS, ammonia and other pa rameters. The Environmental Improvement Project 3. To achieve nil offensive odour at the boundaries of the plant. In 1998 M elbourne Water, assisted by 4. To maximize effluent reuse opportuConnell Wagner, developed a formal nities. Strategy for the Western Treatment Plant to identify the most approp riate w ay for M elbourne Water to comply with the EPA requirements: • Extensive consultation w ith stakeholders • Process mass balance modeling • Examination of land irrigati on economics • Probability-based lifecycle financial evaluation of potential options The final Strategy recomm ended phasing out the application of raw sewage to land by progressively replacing it with lagoon-based treatment systems. The EIP involves a rolling capital program to achieve the replacement of sewage to land practices with improved lagoon- based treatment systems by 2005. T he staged release of land currently irrigated with raw sewage enables progressive implementation of a major reuse scheme for treated effluent. T he broad goals of the EIP are: 1. Compliance with EPA license requirements 2. Ga ining "shareholder value" fo r sewage treatment and land management 3. Compliance with wildlife treaties 4. Environmental sustainability 5. Public health Achievement of these goals is to be managed by the following specific objectives:

-

5. T o consistently operate within Melbourne Water policies. O ther important objectives of the E IP are: 1. To allow for existing and

expected longer tem1 increases in sewage inflow to the WTP. 2. To comply with international wildlife treaties. 3. T o implement processes that are ecologically and environmentally sustainable 4. T o comply with health and safety regulatoty requirements 5. To maxmuze treatment system robustness and flexibility 6. T o maximize shareholder valu e, including life cycle costs T he 55 East Lagoon Upgrade is the fi rst major lagoon augmentation and is an integral part of the E IP. E ngineering initiatives applied in the 55 East Lagoon w ill be reviewed and used in future augmentations.

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With our inspection systems a user con cover a number of diverse areas. The investigation of drain damage is just as possible as the final inspection of newly built laterals. iPEK colour TV systems ore used for the investigation of air conditioning systems and coble pits, power station lines and filte ring units as well as in the reconstruction of buildings and the monitoring of cavities. Experience the benefits and costeffectiveness of our portable colour TV system. The heart of the system is a high resolution solid state colour-TV-camera, which may be continuously focussed from 2 cm to l m. It is equipped with on integrated light ring, ensuring absolute colour stability. In combination with an iPEK crawler, you hove on unbeatable team.

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PROJECT

IMPLEMENTATION

The 55 East Lagoon Project The immense scale o f the project presented unique and difficult challenges both to the design and th e construction of the 55 E ast Lagoo n project. Average dry weather flow is 190 ML/d with peak flows o f up to 900 ML/d. D esign so lution s w e re develo ped w hich , in many cases, were beyond the limits o f conventio nal engineering practices. The principal objectives of the 55 East Lagoon upgrade Aeration zone 1 and 2 which houses the aerators. are: Alli ance and th e Proc ess Design 1. To deliver a 50% redu ction in Workshop. n itrogen load ou tput by D ecember 30, T he Alliance fram.ework encou raged 2001. all m embers to focus on agreed project 2 . T o achieve significant reductions in objectives with the resul t that there was pollutants, incl uding am m onia and ffi c i e n t c o n t r o I a n d p r o j e c t e suspended solids. T his was achieved through management. 3. To re-cycle effluent and m inimize number of key factors includ ing: self a efflu ent discharge into the Bay. managem ent among all members; a share 4. To increase design inflow capacity. of rewards; a resolution of issues without Immediately formal approval for the rigid contract boundaries; the use of E IP Strategy had been given proj ect advanced database system s; open book pla n n i n g c omme n ce d w ith a comprehensive im plementation plan. T his plan considered all contract Table 1 . Design Flows for 55 E Lagoon delivery methods and recommended 190 ML/ d Average dry weather flow the adoption of an Allian ce contract Peak instantaneous d ry weather flow approach with com mon incentives 290 ML/ d fo r all service providers. Peak instantaneous wet weather flow 900 ML/ d T here were two key com ponents Peak flow in 24 Hours 350 ML/d to the success of the project - th e

accounting; and shared proj ect scheduling. T here were four technical issues w hich were identified early in the design process and whi ch needed to be solved fo r the proj ect to be successful. T hese were; the ex tent to which m odifying th e lagoo ns wo uld i mp act o n t h e prod u cti o n o f al g ae, th e amount of nitrogen w hich co uld be r emoved , w ha t actions to take to prevent odour and the wh ether the process adopted would be able to achieve the required levels of disinfec tion . Th e Process D e sign Workshop recommended: 1. T he adoption of an activated sludge configura tion to co ntrol the growth of algae. 2. Th e use of math ematical mod eli ng techniqu es to d ete rmine o ptim u m p rocess design and plant configuratio n. 3. R etaining existing aeration capacity and compou nding th e aeration process by impl ementing a recycle system . Risk Assess me n t and Safe t y H azard identificatio n were also key components of the project delivery strategy. Q ualitati ve Risk Assessment (QRA) was und er take n at t he com mencem ent of the project and regular reviews w ere conducted to

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WATER DECEMBER 2001

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PROJECT

IMPLEMENTATION

ensure that risks incurred were regularly assessed . With the QRA a risk score based o n probability and conseq uence was used to assign levels o f control for specific tasks. Because of the nature of the WTP's operations and the nature of the project environ menta l sta ndards were high and necessitated rigorous applica tio n. The Alliance was able to ensure effec t ive env ironm ental Two of the four clarifiers. management of the site in six key areas: 1. T h e protec t io n of parties. T his created an opportu n ity for ex isting flora and fa una. all team m embers to bring operational, design and constructio n issues together, 2. Th e con trol of air and dust pollution. foc using o n the best possi ble outcom e at 3 . No water pollutio n and/or erosio n. all stages o f the project. 4 . Th e control of construction noise. Separate suppliers were engaged fo r 5 . The safe storage and handling of process design , detail design and the dangerous goods. co nstru ction fo llowing an E O I and 6. Th e ab ili ry to manage and minimize tender processes. waste. The 55 East Lagoon project is 110w able to meet the perforn1a11ce impro11eme11ts specified by the EPA . It also i11creases the capacit )' to harness biogas produced b)' t/1e lagoo11 process. This is used to generate electricit)', thus significant!)' reducing Greenhouse Gas emissions. Financial planning and control was on the basis that the proj ect was delivered in a cost-effective manner. T h is was ac hieved through the setting o f accu rate budgets early in th e plann ing phase and conti n ually reviewi ng and up dati ng these budgets throughout the process design and detail design phases. T he project budget incorporated a contingency of 5% over th e estimated p roject cost.

The Benefits

• A culture of excellence . T ea m m emb ers fo cus on quali ty in desig n and co nstru ction without fee and co ntract issues limiting possibilities. • An optimized design resulting from cross-fun ctional input at all stages. • Fast tracking of th e project w ith overla pping design and construction stages. Fixed cost contract arrangements negate th is advantage due to the requirem e n t s to un de r take eac h p hase

Thiess Services is supported

by an innovative network of technical and human resources. Professionals in the provision of municipal and infrastructure services, we offer: Infrast ructure maint enance services for water and sewerage reticulation systems;

The Alliance

Drainage maint enance services;

A critical initiative

- Wastewater treatment services; and

Th e Alliance contracting strategy was based on a perceived benefit over traditional lump-su m contracting m ethods. The stru cture proved integral to the success of the proj ect, du e to a broad range of benefi ts. T he Alliance consisted of specialist service providers with individual agreements drawn between Melbourne Water and Alliance members. The Alliance contracts were fo rmulated to provide a non-adversarial arrangement between

Four maj o r com pani es were in volved. • Design Consultants Sinclair Knight Merz Pty Ltd Proc ess Design Gutteridge Haskins and Davey Pty Ltd • Construction - John Holland Pty Ltd • Superintendent Connell Wagner

- Hydrographic services.

.

SERVICES For enquiries call 1800 818 293 www.thiess-services.com.au feedback@thiess-services.com.au

WATER DECEMBER 2001

55


PROJECT

sequentially in order to define requirements for pricing. • Significant cost reduction as team members constantly sought cost savings. • B alanced decisions incorporating cost and quality with input from the owner and the operator of the asset. This avoided over/under design and allowed the appropriate targeting of capital. • Optimal time management ensured overall time objectives were met. The project was completed prior to winter 2001 . • Professional fulfillment for all team members. • Shared project risks , such as Environment an O H &S risks , resulted in a uniform and appropriate level of focus. • Knowledge and efficiencies gained from the first lagoon project (SSE) will be applied to the fu ture E IP projects • Minimization of the project cost due to strong finical incentives being allo cated to all Alliance members. Discrete packages of construction work, such a work that demanded the use of sp ecialist e quipme nt and

procurement of materials, were subcontracted by the Constructor and subj ect to competition through tender processed. Performance Driven

Performance fees provided a clear incentive to Allian ce m em b ers. Performance fees were linked to projectrelated outcomes, which w ere common to all Alliance members. T he three main outcomes were cost, time quality. The performance fee arrangement encouraged the service provider or contractor to perform collaboratively in order to n1.eet shared outcomes. The 'open book' nature o f the Alliance allowed expert analysis of work methods and cost estimates. The effluent quality performance fees were available if the lagoon met the future EPA license requirements. Economic and Environmental

There are two categories of economic and environmental benefits achieved by the project; chose achieved during the construction phase and those achieved by the finished project.

SPECIALISING IN ENVIRONMENTAL SERVICES Water Supply & Treatment Water Quality Management Management Systems & Compliance Auditing Water Resources Development, Hydrology, Irrigation & Drainage Wastewater Collection, Treatment & Reuse Environmental AudiVSite Investigations Contamination Assessment & Remediation Hazardous/Industrial Waste Management Solid Waste Management Environmental Impact Statements Environmental Management Planning Emissions Testing & Air Quality Monitoring & System Development Emissions Testing & Air Quality Monitoring

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WATER DECEMBER 2001

IMPLEMENTATION

Ii

ENVIRONMENTAL GROUP NATIONALLY

Dr Peter Nadebaum (03) 9272 6666 NEWCASTLE

Ian Gregson (02) 4929 3255 NSW

Dr Ian Garrard (02) 9412 9999 QLD

Stephen Trainor, George Khouri & Brad Steele (07) 3233 1611 VIC

Ron Edwards & Dr Wayne Drew (03) 9272 6666 WA

Warren Dodge (08) 9220 9300 SA

Paul Lindon (08) 8271 2322

During the construction phase the economic benefi ts (cost savings) were: (a) Cost co n tro l by the u se of Performance l ncentives. (b) The use of a Cost Process Concept. For the finished project the economic benefits achieved by the proj ect are: (a) Protection of the health of Pore Phillip Bay for the benefit of business and recreational users. (b) Design and flexi bili ty for futu re improvements. (c) Potential for long term deferment of major capital investment as loads to the plant increase, or standards are tightened further. (d) An advanced, high capacity treatment facility designed and constructed at a greatly reduced cost co alternatives. Economic

By choosing to upgrade pare of the WTP, Melbourne Water was effectively saving on a huge capital cost without in any way compromising the desired outcomes. M elb ourne W ater wou ld have needed co consider alternative treatment processes such as a full scale M echanical Treatment Plant at a potential cost of up to $7S0M. The capital cost of SSE Lagoon, including the initial capital cost of the lagoons, together with the final upgrade cost, has resulted in a substantially lower financial spend than is typical for similar sized wastewater treatment plants. T he operating cost of the project is also well below that of conventional solutions. This has been achieved by the high degree of automation. Environmental

Since the Western T reatment Plant is a recognised Wildlife Sanctuary, during the construction phase particular attention was placed on protecting the environment, including: • Protection of existing flora and fauna through rigorous adherence to protocols and the training of staff. • Control of air/ dust pollution through restricted ve hi cle movement and ongoing monitoring. • Control of water pollution and erosion through the development of process procedures, which included control of run-off water and re-growth of natural grasses. • Control of noise through a 'plant identification register' and regular noise testing of machinery.


PROJECT

â&#x20AC;˘ Storage and handling of dangerous goods controlled through Material Safety Data Sheets system and Job Safety Analysis. â&#x20AC;˘ Waste Management and Minim.ization thro ugh the development of a procedure to identify, control and record the generatio n of waste caused by construction activities. T h is included metal and timber recycling programs.

Design Concept T he upgrade of the SSE Lagoon prov id es increased capaci t y and improved effiu ent quality with respect tO ammonia, tOtal nitrogen, suspended solids and bioc hemical oxygen demand (BOD) . The design flows for SSE Lagoon are deta iled in Table 1. Lagoon 55 comprises lO ponds, with Po nd 1 being the inlet pond and Pond 10 being the outlet pond. The works assoc iated with the project are mainl y directed at Pond 5, with the constru ction of the Activated Sl udge Plant (ASP). The ASP compri ses of two anoxic zones, two aeration zones and fou r clarifi ers. T h e activated sludge process is arranged in the modifi ed LudzackEttinger (MLE) format for nitrogen removal with forma l clarifiers. The process is located in the first section of Po nd 5 and is fed w ith effiu ent from P ond 4 s u p p lemen t ed wit h Carbonaceous Oxygen D emand (COD) from Pond 1 to sustain the nitrifying populati on as well as tO den itrify part of the nitrogen load. T h e upgrad e also i n vo l ves construction of lagoon transfer structures and recycle pip es and channels, as well as various p ump stations. Operating philosophy

SSE Lagoon is designed to operate continuously all year around , and to cater fo r the different rates associated with th e varying seasons. The system is designed fo r unmanned operation. System operating parameters are m on itored by a SCADA system.

IMPLEMENTATION

Twenty two mixers are located in the anoxic zones, 11 in each of the two zones.

clarifi ers and then to the downstrea m sections of th e lagoon.

Twenty aerat0rs and eight mrygen sensors are located in the aeration zones, with 10 aerators and four oxygen sensors in each of the two zones. Recycle p umps are installed in the concrete wall between Anoxic Zone 1 and Aeration Zone 2. Th e C larifi er basin houses the four clarifiers as well as the R eturn Activated Sludge Pump Station (R AS). Four electromagnetic flow meters, one for each RAS return line are installed in pits in the suction sid e of the return lines.

The anoxic zones are designed to provide conditions suitable for d eni trification where, in the absence of oxygen, nitrates are co nverted to ni trogen gas, which bubbles out of the wastewater, thus reducing the amo u nt of total nitrogen in the waste water.

The Aeration Zones

T he aeratio n zones are designed to provide cond itio ns suitable for nitrificatio n to occur. Comb in ed with high mrygen levels, ammon ia is converted to nitrates. Th e high recycle flow ensures that the nfrrates produced in the aeratio n zone are returned to the anoxic zone for de-nitrification, th us minimizi ng the amount of nitrogen progressin g to the

The Anoxic Zones

The Result The 55E Lagoon project was co111pleted ti111e 111itho11t any reco11rse to the contingeircy The total capital cost lo date for the 55E Lagoon project has been $32M. This is below the budget figure of $35. 6M and represents a sailit1g of $3. 6M. 011

The Author Terry Schubach worked in the Sou th African Water Industry for 10 years as a P roject Manager on a variety of proj ects, specifically in the fields of E lectrical, M echanical, Process and Civil E ngineering before joining John Ho ll and as a Seni or Project Manager.

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Activated Sludge Plant

The ASP provides nitrification and de-nit r ificati on, removes algae, suspended solids, BOD and COD from the wastewater The ASP is constructed in two basins at the western end of Pond 5 . The activated sludge basin is divided into fou r compartments, with two compartments used as anoxic zones and two used as aeration zones. The second basin is the clarifi er basin.

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WATER

AUSTRALASIAN STANDARDS FOR ON-SITE SEWAGE MANAGEMENT: APPLICATION IN THE SYDNEY DRINKING WATER CATCHMENTS K Charles, N Ashbolt, D Roser, D Deere, R McGuinness Abstract Aus t ralasia n Standard AS / NZS 1547:2000 provides the framework for improved design of new on-site sewage n1anagement systems (OSMS) through greater consideration oflocal site and soil conditions, and improved pe1formance of existing syste ms through the promotion of proper operation and maintenance. H owever, its abili ty to protect the environment and public health is less satisfactory due to limited criteria for management of pathogens (viruses and

protozoa) and nutrients (nitrogen and phosphorous). In the Sydney Catchment Authority area of operation patho gen and nutrient pollution fro m OSMS is of particular co ncern. T hese drinking water catchments are the context used for assessing the applicability of AS/NZS 1547:2000 to sensitive environments, an assessment which has highlighted the importance of the management sections ability to improve the performance of OSMS in the short term through better operation and

maintenance, and the education of stakeholders to ensure adequate consideration of qualitative criteria for pathogens and nutrients in OS MS design. It also identifies possible improvements for the design of new and the managemen t of ex istin g OSMS, including decision n1.aking tools for setting buffer distances to protect water quality. Keywords: On-site sewage management, Australian Standards, Sydney Catchment Authority, pathogen, nutrient

Introduction Sustained functioning of on-site sewage management systems (OSMS) is required to p rotect the environment and public health, and proper design and operation and maintenance (O&M) is vital to ensure sustainability and continued performance. In sensitive catchments the risks and potential impact from poor system performance are greater still . The Sydney Catchment Authority (SCA) area of operation, providing potable water for over 4 million people, comprises several such sensitive catchments. The Sydney Catchment Authority (SCA) aims to protect water quality in these catchments, including minimising risks to human h ealth and t h e e n vi ronment from pathogens and nutrients. H ence, the high rates of OSMS failure rep orted in NSW are a concern for the SCA. O'Neill et al. (1993) reported visible surfac ing efflue nt at over 40% of absorp tion trenches . Coote (1995) reported 95% of aerated wastewater treatment systems (AWTS) failing to comply with at least one parameter in the NSW efiluent guidelines (DLG, 1998). Australian Water Technologies (1999) reported densities of thermotolerant (faecal) coliforms in effluent pooled on the soil surface from absorption trenches and spray irrigation areas of up to 10 7 colony forming units (cfu) per 100 mL, representing a p otential risk to human

58

WATER DECEMBER 2001


WATER

Table 1: Comparison of Aust ralasian and internation al 0SMS standards Standard/ s

Australia

AS 1547 :1994 ¡ Disposal systems for effluent from domestic premises" (Standards Australia, 1994)

Systems

Site evaluation

Land application system design criteria

Performance Criteria

Comments

& Management

Surface and subsurface disposal systems . Collection wells and grey water treatment tanks.

Depth of soil, permeability, climate, seasonal changes in soil and groundwater, seepage , runoff, impact on neighbours, life expectancy of system and area available for primary and alternative systems.

300 L of wastewater produced per bedroom/ day (town water). Permeability based loading rate.

Quantitative criteria for surface irrigation.

Prescriptive standard. Inadequate coverage of nutrients and pathogens1

Australasia AS/ NZS 1547:2000 "On-site domesticwastewater management" (Standards Austral ia / Standards New Zealand , 2000)

Surface and subsurface land application systems, including mounds.

Desktop study, site and soi l check and site and soil assessment, including soi l properties, vegetation, fill, slope, exposure and salinity.

Wastewater production 180 L per person/ day (t own water). Loading rate from soi l texture and structure. Consideration of effluent treatment.

Qualitative criteria for system performance, management, construction and inst allation and design.2 Criteria for irrigation of effluent. Management information for administ ration, education, monitoring, and O&M (for guidance only).

Performance based. Inadequate coverage of nutrients and pathogens 1

USA

D5879 "Surface Site Characterisation for On-Site Septic Systems " (ASTM, 1 995) D5921 "Subsurface Site Characterisation of Test Pits for On-Site Sept ic Systems" (ASTM, 1996a) D5925 "Preliminary Sizing and Delineation of Soil Absorption Field Areas for On-Site Septic Systems " (ASTM , 1996b)

Subsurface land Desktop study and application site assessments. systems, Subsurface including assessment includes filter beds. limiting depth based on changes in permeabi lity, rupture resistance, cement ation, penetration resistance , roots and pores.

Wastewater product ion is 568L per bedroom/ day. Loading rates , based on soil texture and structure , may be higher than AS/ NZS 1547:2000.

Nil

Inadequate coverage of nutrients and pathogens.

Europe 3

BS 6297:1983 "Code of practice for design and installation of small sewage treatment works and cesspools" (British Standards, 1983)

Disposal to waterways, surface and subsurface land appl ication systems.

Includes installation approval, system integrity and alarms to indicate failure or malfunction.

No coverage of nutrients and pathogens.

Desktop study and Wastewater production is site assessment of 120L per person/day. potential noise , Percolation based potential for pollution loading rates, lower t han of waterways, slope, AS/ NZS 1547:2000 prevail ing wind, flooding for equivalent permeability. potent ial, water table depth and percolation. Consideration of effluent treatment.

Notes

1 Acknowledges that a low thermotolerant coliform count does not imply an absence of pathogens 2 Includes qualitative performance criteria for nutrients and pathogens 3 The available European standard , EN 12566-1:2000 (European Committee for Standardisation , 2000). only addresses septic tanks , however, additional standards are being developed for 'Soil Infiltration Systems' and 'Filtration Systems¡.

health. Similar data has been reported fro m other states. T hirty percent of absorptio n trenches had visible surface flow an d 73% performed unsatisfactorily in South Australia (Geary, 1992). In Q ueensland, 39% of trenches had poor petformance or surface seepage Qelliffe et al., 1994) and 70% of A W T S failed to

achieve the required effluent quality (Beavers et al., 1999) . T he primaty causes of performance failure are poor design, including siting and sizing, and inadequate O&M, which are o ften caused by inadequate understanding of design Jjmitations and failure modes, fi nancial pressures and change of

usage or owner. The above scudjes did not specifically identify adverse environmental imp acts, or directly measure effects on h uman health or ecology. H owever, potential adverse effects are expected if guideline values are not met. T herefore, the SCA is vitally interested in w hether the new Australasian Standard WATER DECEMBER 2001

59


WATER

requirements fo r abso rption , evapotranspiration and irrigation disposal systems, co!Jection wells Median Maximum Applies to and grey water treatment tanks, surface spray, covered surface 30 with disposal area design based on drip, subsurface drip the long-term acceptance rate surface spray, covered surface S30 45 (LTAR) of the site, a permedrip, subsurface drip ability-based design hydraulic surface spray S10 20 loading. AS/NZS 1547: 2000 (in 4 out of introduces the term ' land appli5 samples) cation' to replace 'disposal' to surface spray ~0.5 acknow ledge the treatment provided by the soil matrix and sustainable and protect the environment ecosystems, and improves OSMS sustainand public health. This paper evaluates ability through: whether AS/NZS 1547:2000 will fully • increased consideration of local site and achieve these aims by assessing whether environmental conditions in site assessits pathogen and nutrient management ments and sizing of land application recommendations and procedures reflect systems; best possible managen1ent practice. • replacement of the LTAR with a Design Loading Rate (DLR) based on a Overall detailed soil assessment, including soil AS/NZS 1547:2000 'On-si te texture and stru cture; and Domestic-Wastewater Management' is a • inclusion of management recommensignificant advance on the previous dations and qualitati ve performance standard, AS 1547:1994, especially with criteria. respect to improved efiluent land appliIn these and other respects AS/NZS cation system design criteria and th e 1547:2000 com.pares well with internaintroduction of management recommentional on-site effiuent disposal standards dations. AS 1547: 1994 included design (Table 1). Further notable featu res of AS/NZS 1547:2000 are as follows.

Table 2. Effluent Quality Requirements for 0SMS Parameter

Biochemica l oxygen demand (BO D) (g/m·3 ) Suspended Solids (g/m·3) Thermotolerant coliforms (cfu/100 mL·1 )

Total chlorine (g/m 3)

for domestic wastewater management, AS/NZS 1547:2000 will reduce the number of failures, promote better human health and ecological protection in sensitive environments such as the Sydney drinking water catchments, and adequately address the pathogen and nutrient concerns.

AS/NZS 1547:2000 The new Australasian Standard for onsite sewage management, AS/NZS 1547:2000, integrates design and O&M with other management issues and is intended to promote a great improvement in OSMS performance. AS/NZS 1547:2000 requires that OSMS designs are

Site Evaluation Aspects

The AS /NZS 1547:2000 site evaluation addresses public health , environmental, legal and econo mic considerations, as well as site and soil characteristics, by requiring a desktop study, preliminary site and soil check (SSC) and detailed soil assessment. This provides information for selection of design parameters, treatment system selection and land application system location. The SSC ensures a broad range of site and environmental factors are considered in system siting and design. The soil assessm ent attempts to ensure land application area is sustainable by prediction o f soil permeability through classification, hence, reducing failure due to surfacing effiuent. Design Aspects

AS/NZS 1547:2000 recommends varying effiuent land application areas based on design wastewater production rates, depending on water supply and usage factors, which are generally more conservative than previous values. Design wastewater production rates can be based on the number of bedrooms or occupants in a dw elling. The former, be ing controlled by co un cil development processes, better guarantees usage will not exceed the design.

60

WATER DECEMBER 2001


WATER

Table 3. OSMS Survey Results System Type

Number in SCA area of operation

Percent of Total

13,500

73

AWTS

3 ,744

20

Pump out

1 ,168

6

53

<1 100

Septic tank/ Absorption trench

Other* Total

18,465

* Includes sand filters, composting toilets, grey-water t reatment systems, mounds, evapotranspi ration beds and constructed wetlands

The DLR varies according to local soil properties, the land-app lication system type and th e eilluent quality . DLRs are generally lower than the LTARs and, with the c h ange in design wastewa t er production rate, wilJ generally result in the need for larger land application areas. Performance Criteria & Management

AS/NZS 1547:2000 incorporates qualitative performance criteria for wastewater systems, evaluation of site and soil characteristics, construction and instaUation, and management, and quantitative performance criteria for systems using irrigation (Table 2). T h e performan ce criteri a require the life expectancy of an OSMS to be above 15 years (unless otherwise nominated). Management in AS/NZS 1547:2000 aims to ensu re sustainable long-term performance and protect public health, the e n v ir o n m e nt a nd p ubl i c amenity. Potentially, management can redu ce the risk fro m OSMS failure and poor performance through improved O&M and through: • education of stakeh olders, including accreditation of design ers and site assessors; • recording OSMS information o n the property titl e, and hence, chan ges of owner and information managem ent; • regu lar monitoring of system perform ance; and • the preparation of O&M guidelines.

OSMS in the SCA area of operation A survey of councils in the SCA area of operation, undertaken by the Centre fo r Water and Waste T ec hn ology (CW WT) (u npublished data), has identified over 18 000 OSMS. Seventythree percent were septic tank/ absorption trench systems. AWTS were th e second most pop ular (Table 3). In the SCA area of operation, pathogen contamination of the drinking water catchments is the key public health risk. Nutrients, particularly phosphorus, are also of concern as they impact on native vegetation and can cause eutrop hication,

which has public health and environmental implications. OSMS are potentially significant sources of both. The primary pathogens of concern are human enteric viruses and Cryptosporidiw-11. Pathogen transport from land-appl ica tion of OSMS eillu ent to groundwater has bee n reported (Curry, 200; Scandura & Sobsey, 1997) and has been li nked to drinking water outbreaks in the US (Scandu ra & Sobsey, 1997). Runoff from unsewered urban areas was found to be the fourth most signi fi cant so urce of Cryptosporidi11111 in the Sydney catchm ents (Swanson et al., 2000).

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Phosphorous removal from land applied efflue n t primarily occu rs in unsaturated soil, with up to 98% b eing immobilised thro ugh sorption and precipitation (Bicki et al., 1984). In groundwater, phosphorous transport is retard ed by reversibl e sorptio n reactions, however, phosphorous plume transport has been detected 180111 fro m its sou rce (Cu rry, 2000). Phosphorou s transport impacts on surface water have been identified from absorption trenches within 50 111 of water or where insufficient unsaturated soil d ep th occurs (B icki et al., 1984) . Additionally, nitrate contamination of grou ndwater is a 'virtual certainty' where grou nd water recharge occurs (Brouwer, 1983). Hence, appropri ate selectio n , sizing and management ofland application areas is required to protect water quality.

Weaknesses of AS/NZS 1547:2000 in the SCA area of operation The d esign criteria 111 AS / NZS 1547:2000 should reduce the risks to water quality in the Sydney catchments fro m OSMS in th e lon g-term. How eve r,

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WATER DECEMBER 2001

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WATER

concerns exist regarding the secondaty effi uent D LRs for absorption trenches, which result in small areas in high permeability soils, due to the potential for groundwater contam ination or failure fr om clogging where effluent does not comply w ith criteria. Stakehold e r ed ucation, as recommended i n the managem ent sectio n , is essen tial for the success of AS/NZS 1547:2000. T o address this, and hence the a b ove des i gn co n c e rn , AS/NZS 154 7 :2000 recommends accreditation of certain stakeholders but no guidance on accredi tation course content is inclu ded. Additionally, while the m anagem en t section is informative, implem entation is not required by AS/NZS 1547:2000 fo r compliance. The O &M rec omme nda tion s i n AS/N ZS 1547:2000 address many of the concerns regarding existing systems in the SCA area of operation. The success of these recom mendations, however, may depend on the availability of resources for inspections. The current failure detection m ethods d o n ot relate directly to environmental and public health impacts, and hence, may o ffer inadequate protection o f

water quaJity in the Sydney drinking water catchments. T he inspection outcomes are also limited by a lack of gu idance o n remedial measures. And while AS/N ZS 1547:2000 does consider life expectancy, good record keeping and a manage ment plan to assess con tinu ing life expectancy or rem edial action are only assumed . The p erformance criteria require that OSM S p rotect publi c h ealt h , the en viro nment and public and community amenity. H owever, the standard p rovides limited guidance on how co achieve these aims, particu larly on pathogen and n utrient issues th at are implicit in these aims, and he nce, do es not appear to adequately address the prim ary water q uality concerns in the Sydney drinking water catch men ts. Pathogens

For over twenty years, microbiologists have report ed that th erm oto lera nt coliforms will not reliably indicate the presence of viruses and parasitic protozoa. Coliforms do n ot su rvive as lo n g, especially with system s using chlo ri natio n (Sobsey et al., 1989; R ennecker et al., 2000), and, being larger than the

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viruses, they are fi ltered o ut more effectively in subsurface environments (Mader and Merkle, 2000; Lance & Gerba, 1984; Scandura & Sobsey, 1997) . Yet more su itable index organisms for th ese pathogens are not yet routinely used (Ash bolt et al., 2001). AS/ N ZS 1547:2000, similarly to its predecessor, w hile recognising the inadequacy of thermotoleran t coliforms as an indicator of public health risk still, uses this as the sole microbial analyte, and places the responsibility to ensure health risks are tolerable on local authorities who tend to have lin1ited m icrobiological expertise. Testing fo r a ran ge o f faeca l bacteria (including sp ore-forming Clostridium pe,jri11gens), as well as coliphages (viruses to selected colifo rm s) , provides more reliable inform ation on the poss ible presence of p at h oge n ic o rgan ism s. Additionally, coliphages have been widely used as surrogates of viruses in studies of fate and transport in groundwater (Cuny, 2000; Deborde et al., 1999). The US EPA Proposed G round W ater Rule (2000) recomm ends E. coli, Entero co cci an d coli phage be used as monito ring tools for faeca l con tami nation. Similar regulation in Australia would improve identification of risk fro m faecal contamination, and improve quantification of risk associated w ith OSM S o n a local scale, such as fr om irrigation , as well as on a catchment scale. The adequ ate imp le men tation of the q ualitative performance criteria , w ith regard to path ogens, d uring OS M S design relies on th e education and local knowledge of the designer. For exam ple, impacts o f virus survival and transport in grou ndwater n eed to be considered b efo re rec om me nding h igh DLRs. W itho u t appropriate knowledge qualitative perform an ce criteria are inadequate managem ent tools. Buffer zones are an importan t tool for attenu ating pathogens and n utri en ts (Ba rling & M oore, 1992) . AS/NZS 1547:2000 does not recommend bu ffer zones o r provide tools fo r developi ng buffers appropriate for local conditions, placin g responsib ility on often po orly resourced local authorities. Nutrients

AS/N ZS 1547:2000 does not include quantitative perform ance criteria fo r nutrients, other than BOD , bu t addresses them through identification of the impacts on water quality and vegetatio n in land application area design, and consideration of system life expectancy. These qualitative criteria, and associated nu trient balances, rely on designer expertise to


WATER

adequately consider site and environmental conditions, and regulatory authorities. AS/NZS 1547:2000 does not provide sufficient links to receiving water quality. For example, it is hard to see how design criteria for a single system can be related to the Healthy Rivers Commission (1998) water qnality objectives of 50 pg/L total phosphorus and 700 µg/L total nitrogen, particularly when several landuses occur in the catchment. Nor is AS/NZS 1547:2000 yet linked to the new ANZECC & ARMCANZ (2000) guidelines (draft first circulated in ·1999) which provide various guides for setting water quality objectives and include a shared national objective, with guidance on issues that may arise in individual circumstances and the flexibility to address these issues.

Conclusions The reported high rates of OSMS performance failure indicate a need for improved design and management to protect the environment, public health and community amenity. AS/NZS 1547:2000 addresses this need through consideration of a broader range of site and soil design factors and promotion of O&M and education. However, AS/NZS 1547:2000 appeats to be deficient in addressing pathogen and nutrient issues in sensitive catchments, such as the Sydney drinking water catchments. Following the ANZECC & ARMCANZ (2000) model, a number of possible improvements should be explored: • Development of an effective, standardised method for failure detection during inspections, better methods for rehabilitation and subsequent monitoring of failing systems and appropriate criteria for decommissioning, upgrading or replacement, tracking of desludging and AWTS maintenance, and auditing of the service providers to improve O&M. • Development of tools for undertaking nutrient balances and identifying buffer distances required for single lots and subdivisions, in wet and dry weather, to protect water quality, based on effluent quality, site conditions and receiving environment. • Enhanced but workable graded eflluent quality criteria that include pathogens and nutrients, with monitoring of long-term compliance and performance of innovative systems. • Means of linking AS/NZS 1547:2000 to water quality targets and other relevant environmental management tools. The education of stakeholders, and hence the management section, is fonda-

mental in ensuring the proper implementation of AS/NZS 1547:2000. Ultimately, the success of this standard will depend on the resources available to local government and other regulatory authorities to allow them to address the issues in their area, and enforce restrictions where necessa1y. For the SCA, this will include setting criteria for system performance and buffer distances, and promoting better methods for assessing pathogen and nutrient impacts. Recognising the need for improvements complementary to AS/NZS 1547:2000, the SCA and the CWWT are developing a catchment OSMS risk assessment, encompassing septic tanks, A WTS (chlorine and ultraviolet disinfection) and Ecomax systems. The risk assessment will provide information on cumulative catchment-scale impact of OSMS and most effective methods of managing risk, and a mass balance of nutrient inputs from OSMS in the Sydney catchments where algal blooms are a problem for water quality managers. Ultraviolet disinfection and Ecomax systems are being investigated as potential alternatives for high-risk areas, especially

their effectiveness for removing a range of pathogens, nutrients and indicators. Additionally, experiments of fate and transport of pathogens and nutrients will be undertaken to provide a quantitative basis for buffer design and size. The intended outcome of this work is a comprehensive catchment management strategy for OSMS in sensitive catchments to which other local government and regulat01y authorities will be encouraged to contribute.

Acknowledgements The assistance of those individuals who have aided in the development of this paper and in the associated research is greatly appreciated. In particular thanks to Stephen Manson, SCA, and the staff of the councils in the SCA area of operation.

References ANZECC and ARMCANZ (2000). Australian and New Zealand Guidelines for Fresh and Marine Water Quality. (National Water Quality Management Strategy No 4.) Australian & New Zealand Environment & Conservation Council.

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Ashbolt NJ , Grabow, W . 0. K. and Snozzi, M. (2001). l11dicators of 111icrobial water quality. In Fewtrell , L. and Bartram, J. (ed.), Water Quality: Guidelines, Standards and Health. Risk assessm ent and management for waterrelated infectious disease. WHO, (in press) . ASTM (1995). D 5879 - 95 Standard Practice for Surface Site C haracterization for On-Site Septic Systems. American Society for Testing and Mate rials, W ashington D .C.. ASTM (1996a). D 5921 - 96 Standard Practice fo r Subsurface Site C haracterization of Test Pits for On-Site Septic Systems. American Society for Testing and Mate1ials, Washington D.C .. ASTM (19966). D 5925 - 96 Standard Practice for Preliminary Sizing and Delineation of Soil Absorption Field Areas for On-Site Septic Systems. American Society for T esting and Materials, Washington D.C.. Au stralian Wate r Techno logies ( 1999). Assessments of the Environmental Impacts of Unsewered Areas in the Werriberri Creek Catchment. AWT Environment, Science and Technology, Sydney. Barling RD and l D Moore (1992). The Role of Buffer Strips in the Management of Wate rway Pollution. In: T/, e Role of B1iffer

Strips i11 the Ma1iage111w t of Watenvay Pollution fro111 Diffi,se Urba11 a11d Rum/ Sources. Proceedings of a Workshop, October 1992. (Eds. : Wood full, J, B Finlayson an d T M cMahon) Land and Water R esources Research and Development Corporation, Canberra, p. 44.

Beavers P, l Tu lly and A W oolley (1999). Performance evaluation of On-site Aerated ¡wastewater Treatment Systems. In: Proceedi11gs of 0 11-site '99 Coiiferwce: Maki11g 011-site wastewater syste111s work; 13th-1 5th July 1999, University of New England. (Ed.: Patterson, R.A.) Lanfax Laboratoiies, Armidale, pp. 4552. Bicki T J, R B B rown, M E C ollins, R. S Mansell and D F Rothwell (1984). Impact of On-site Sewage Disposal Systems on Surface and Groundwater Quality. Florida Department of H ealth and R ehabilitative Services, USA. British Standards (1983). BS 6297:1983 Code of practice for D esign and installation of small sewage treatment works and cesspools. British Standards Institution, London. Brouwer J (1983). Land Capability for Septic Tank Efiluent Absorption Fields. Part B: R eview of Research and R egulations in Australia and Overseas for on-site W aste Water Disposal. (Australian W ater Resources Council Technical Paper No. 80.) Australian Government Publishing Service, Canberra. Coote B (1995) . Aerated Septic Systems for Camden Council. AWT R eport 95/ 194. Sydney Water Corp., Sydney. Curry D S (2000) . Final Report for the Septic Siting Study. New York C ity D epartment of Environmental Protection, New York. DeBorde DC, WW Woessner, QT Kiley and P BaU (1999). R apid transport of viruses in a floodplain aquifer. Wat. Res. 33:2229-2238.

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DLG (1998) . Environment and Health Protection Guidelines: O n-site Sewage M anagement fo r Single H ouseholds. Department of Local Go vern men t, NSW. European Committee for Standardization (2000). EN 12566-1 :2000 Small wastewater treatment systems for up to 50 PT - Part 1: Prcfab1icated septic tanks. CEN , London. Geary P (1992). Di ffuse pollution from wastewater disposal in small unsewered communities. Aust. ). Soil & Wat. Co11serv. 5( 1):28-33. Healthy R..ivers Commissio n (1998) . Independent Inquiry into the Hawkesbury Nepcan River System , Final R eport. H ealth y Ri vers Commissio n, Sydney. J elliffe PA, G Sabburg and J Wolff (1994). Key fa ctors in minimising water pollution from unsewered areas. AWW A 16th Federal Convention :85-90 . Lance J C and G erba C P (1984) . Virus movement in soil during saturated and unsaturated flow. Appl. Enviro11. Microbial. 47, 335-337. Macler B A and J C Merkle (2000) . Current knowl edge on grou ndwate r microbial pathogens and their control. H ydrogeology). 8 (1): 29-40. O'Neill RA , G K Roads and RN Wiese (1993). On-site waste water treatment and disposal in NSW. School of Civil and Environmental E ngineering, UTS,. R.ennecker J L, A M Driedger, S A Rubin and B J Marinas (2000). Synergy in sequential inactivation of Cryptosporidium parvu111 with ozone/free chlorine and ozone/ monochloramine . Wat. Res. 34(17):4 121- 4 130. Scandura] E and MD Sobsey (1997) . Viral and bacterial contamination of groundwater fro m on- site sewage treatment systems. Wat . Sci. Teel,. 35(1 1-12): 141 -146. Sobsey MD (1989). Inactivation of health-related microorganisms in water by disinfection processes. Wat. Sci. Teel,. 21(3):179-195. Standards Australia (1994). Disposal systems for eilluent from do mestic premises. Standards Australia, Homebush. Standards Australia/ Standards New Zealand (2000) . AS/NZS 1547:2000 On-s ite domestic-wastewater management. Standards Australia, H omebush . Swanson P, A Davidson, P H awkins and M C unnin g h am (20 0 0). Sources of Cryptospo ridium and Giardia in th e Warragamba water supply catchment. AWT, Sydney. U .S. Environme ntal Protection Agency (2000). National Prima r y Drinki n g Wat e r Regulations: Ground Water Rule; Proposed Rules. Federal Register, Vol. 65, No. 91 ed. US-EPA.

Authors Katrina Charles, Nicholas Ashbolt and David Roser are w ith the Centre fo r Water and Waste T echnology (CWWT), School of Civil and E nvironmental Engineering, University of New South Wales, NSW 2052 , ema il: cwwt@ civeng.unsw.edu .au. Daniel Deere and Robert McGuinness are w ith the Sydney Catchment Authority, Penrith , NSW 2750.

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TRAINING FOR OPERATIONAL STAFF: THE NATIONAL WATER INDUSTRY TRAINING PACKAGE 2000 Th is package was endorsed in 1999 and is the culmjnation oflong and significant efforts o f many cont rib u tin g organisations to industry and training reform agendas that have been ongoing since the early 1990's. Austra lia now has nationally recognised, tra nspo r ta ble and eq uitabl e q u a Ii f i c a t i o n s b a s e d u p o n t h e achievement of "competencies" that more truly reflect current business needs of modern industry. A revision of this package referred to as the harmonised package is due for endorsement later this year. This new version wi!J include a Certifi cate IV in Water Industry Operations. At least two major Centres are now offering relevant courses for Australian operators.

Rod Arthur, Director and Don Mackay, Principal Teacher, Open Learning Institute of TAFE, recognise Lew Maguire's (right) contribution to Operations training through 30 years.

The Open Learning Institute in Brisbane

The Water Industry Training Centre, Geelong, Victoria

This governm ent educational institution has long been a foc us for training throughou t Q ueensland, under the aegis of Principal T eacher, Don Mackay T he new courses at OLI have been w ritten to comply with th e National Water Industry Training Package 2000 requirements and provide the substance behind the rhetoric of training fo r the nati ona!Jy recognised Certificate II and III in Water Industry Operations. C urrently O LI has chosen to concentrate its development resou rces on the fields of Water and Wastewater T reatment Plant Operation. Gone are the days when a student had to pass a number of subjects to achieve a qu ali fication. Studen ts in today's environment w i!J be expected to dem onstrate "competence" in their field of study as required under the National Training Package guidelines. At OLI, all courses are provided through the distance education mode and can be substantia!Jy completed at their own workplace under superv1S1on of in-house staff and O LI teachers. Further information from Don Mackay, 0 7 3259 4282 email Donald.Mackay@det.qld.gov.a11

T he need for formal operator training was recognised in the 1970s by th e Victorian Branch of the Australian Water and W astewater Association, and with the cooperation of the government authorities of the day a T raining Centre was set up in 1978. It was origina!Jy based in Werribee, close to M elbourne Water's W estern Treatment Plant, but moved to D eakin University in 1996, continuing to provide a structured training program, which is consistent with the N ational Package. "The W ater Industry Training Centre P ty Ltd." was established in 200 1 and now owns the assets of the Governm ent Business Enterprise, and has th ree Directors, John Park, Stephen W ilson and Ken H erbert. The new organisation is a R egistered Training Organisation with authority to deliver the National Water Indust1y Trairung Package. It still operates from the campus of Deakin U niversity, Geelo n g, and offers tra ining both nationally and internationally, available in several delive1y modes which include: • Off-j o b training at the Ce ntre (regul arly scheduled) • Off-job training at regional centres (on request)

• Distance learning modules • On-job competency assessment by an Assessor The basic certificates and uruts of competency are su mmarised in Table 1. Each provider has their own system for running the necessary courses. For example, the Queensland O LI course fo r the technical competency fo r Certificate II , wate r treatmen t is as shown in Table 1.

The course structure fo r the Techrucal Competency for Ce rtific ate Ill , Wastewater T reatment, is shown in Table

3. Other streams in the National Package are So urce Mana ge m e nt , Wa t er Di st r ib u tion System O p eration , Wastewa t er Collection System Operation. Simila r mixes of course work and onthe-job tra irung are run by the Water Industry Training Centre in Geelong. This Centre regula rl y co n ducts training p rograms in Victoria an d Tasmania but has also recently provided training in New South Wales, South Australia and Indonesia. Further information from John Park 03 5244 0800 , ema il parky @ deakill. edit. au WATER DECEMBER 2001

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Table 1. The Certificates and Units of Competency Certificate II In Water Industry Operations (Water Treat ment)

Certificate II In Water Industry Operations (Wastewater Treatment)

Competencies

Competencies

Core:

Core:

UTWNWS010A

Follow Defi ned OH&S Policies and Procedures

UTWNWS010A

Follow Defined 0H&S Policies and Procedures

UTWNWS020A

Plan and Organise Personal Work Activities

UTWNWS020A

Plan and Organise Personal Work Activities

UTWNWS030 A

Work in a Team Environment

UTWNWS030A

Work in a Team Environment

Implement Environmental Procedures

UTWNWS040A

Implement Environmental Procedures

UTWNWS040A

Technical:

Technical:

UTWNWS600A

Monitor and Operate Water Treatment Processes

Certificate Ill in Water Industry Operations (Water Treatment) Competencies

UTWNWS620A

Monitor and Operate Wastewater Treatment Processes

Certificate Ill in Water Industry Operations (Wastewater Treatment) Competencies

Core:

Core:

UTWNWS050A

Improve Customer Relations

UTWNWS060A Monitor and Implement the Application of Environmental Plans and Procedures Technical:

UTWNWS640A

UTWNWS050A

Improve Customer Relations

UTWNWS060A

Monitor and Implement the Application of Environmental Plans and Procedu res

Technical:

Monitor and Co-ordinate Water Treatment Processes

UTWNWS650A

Monitor and Co-ordinate Wastewater Treatment Processes

Table 2 . Certificate II , Water Treatment Nominal Hours

Unit Type

600A01

20

FTAB

600A02

15

FTA

Foundation Chemistry

600A03

15

FTA

Introductory Microbiology

600A04

5

FTA

Water Quality Parameters

600A05

10

TA

Basic Water Treatment

600A06

TA

600A07

90

Process and Operation Introduction to Laboratory Practice

600A08

50

TAB

Monitor and Operate a Water Treatment Process

600A09

25

WA

Module of Training/ Assessment

Module UTWNWS.

Introduction t o the Water Industry Foundation Maths

Technical Competency

UTWNWS600A Monitor and Operate Water Treatment Processes

Table 3. Certificate Ill, Wast ewat er Treatment Technical Competency

Module of Training/ Assessment

Module UTWNWS.

Nominal Hours

Unit Type

Foundation Physics and Introductory Hydraulics

650A01

20

FTA

Monitor and

Introduction to Drawing Conventions, Sketching and Plan Readi ng

650A02

20

FTA

Co-ordinate

Introductory Maintenance of Plant Equipment and Machinery

650A03

25

FTA

Wastewater

Introductory Computer Skills

650A04

25

FTA

Treatment

Advanced Wastewater Treatment

650A05

140

TA

Processes

Process and Operation

650A06

Advanced Wastewater Process Monitoring

600A07

80

TAB

Monitor and Co-ordinate a Wastewater Treatment Process A

650A08

40

WA

Monitor and Co-ordinate a Wastewater Treatment Process B

600A09

60

WA

UTWNWS650A

A = Assessment

T = Train ing

F = Foundation underpinning knowledge

W = Workplace activities/assessment

66

WATER DECEMBER 20 0 1

B = Block release

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Water Journal December 2001  

Water Journal December 2001