WASTEWATER Water Corporation of Western Australia C'vJCWA), and are owned and funded either privately o r publicly. They cover diverse conditions with testing in place for operational data. User information is also being gathered. Geraldton A three- year trial is being undertaken at Geraldton. T his trial u ses all laundry and bathroom greywater from a single domestic house at Mt Tarcoola to irrigate ornamental garden areas by sub-
South Fremantle Greywater from two homes in builtup residential Fremantle is passed through a standard septic tank for sedimentation, then distributed subsurface to shrubbery in a public park situated on a corner block ofland. The 1500 litre sedimentation tank meets HDWA septic tank standards and effiuent can be diverted to either of two subsurface fields (see Figure 4). On one arm the effiuent distributes onto an Ecomax-designed bed of red mud (byproduct of bauxitt processing) before takeup by vegetation. The other arm, a sta ndby, distribu tes effluent along a subsoil d rain laid in an organic humus filter bed. Surface and groundwater conditi ons are monitored. The settling tank, when examined in August 1996, had accumulated onJy a 20 to 30 mm sludge layer since startup in M arch 1995. The principal test aspects are: • the effect of septic-tank settling on effluent quality and infi ltration • avoidance of surface ponding • the effect of irrigation of vegetation and the effect on the aquifer.
' ... .1n many count ry areas ... extensive greywater recycling is carried on illegally' surface soak pots. The proj ect was funded jointly in J an uary 1994 by the National Landcare Program and the then Wate r Au tho rity of Western Australia. After scree ning to remove ha ir and li nt, greywater is pumped to fou r distribu tion tanks and gravitates through 10 mm diamater distributors to subsurface soak pots, consisting of up to 30 inverted plastic funnels, th roughout garden areas. System monitor-ing starts with the householder keeping records of the typ es of p rincipal additives, cleaning agents etc, discharged in the greywater. Analyses of the greywaterirrigated garden soil will be carried out for any residual effects on the sandy (with a small clay fraction) subsoil. As a water conservation 1neasure, a small hand basin for toilet use rs discharges to the toilet cistern. The pri ncipal test aspects are: • screening and pumping raw greywater • distribution by low-head gravity reticulation through 10 mm tubing • effect of greywater use on garden soil • feasibility of using handbasin water for toilet fl ushing. Cottesloe In a project in Cottesloe greywater from the kitchen, bath room and laundry of a single suburban home of fou r people is initially treated by a bioMax Model ClO anaerobic/aerobic wastewa ter treatment uni t, modified fo r lower organic loading. Effluent, after chlorine disinfec tion, is pumped to underground D ripmaster drippers fo r irrigation o f garden shrubs and groundcover. T he installation is p rivately owned and operated. The principal test aspects are: • effectiveness of modi fication to the bioMax unit for greywater treatment • effectiveness of D ripmaster irrigation drippers. 20
WATER MARCH/APRIL 1998
Palmyra At Palmyra greywater from the kitchens, bathrooms and laund ries of six aged-couples units situat ed close to Fremantle is biologically treated and disinfected for u se in toilet flushing and garden irrigation. The project, fu nded under the Building B etter Cities Program, co mmenced operation in August 1995 and is owned by W estern Australia's housing authority, Homeswest. An Aquarius biological treatment unit produces a secondary-grade effl ue nt for di sinfection by 30- minute chlorine contact to not exceed the levels of thermo-tolerant colifonn org-anisms in Guidelines for Use of Recla imed Water in Australia (NHMRC/AWRC, 1987). The effluent is stored, then used fo r toilet flushing and irrigation of garden s by m eans of undergound drippers. The gardens are fenced and ornamental only, situated on silica sand with a low clay frac tion . T he principal test aspects are: • flow quantity measuring • sui tability of the aerobic treatment unit for greywater (low orga nic load) treatment • d isinfection effectiveness after chlorination and sto rage • feasibility o f reuse fo r toilet fl ushing and irrigation
Sandy loam mounding with grass, shrubs or ground cover
Scarified base soil \... 25 mm laterals. 2 m spacing, minimum 3 mm holes at 1 m intervals
Aerobic and sandy loam layer
Scarified base and improved soil layer
Figure 1, 2, and 3 Approved filtered effluent app lication methods