8/9/2019 The Grove Wastewater Reuse Fact Sheet

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The Grove Library and Community Centre is jointly funded by

the Town of Cottesloe, Shire of Peppermint Grove and Town of

Mosman Park, and is supported by funding from the AustralianGovernment under the Green Precincts Program.

 Josh Byrne

Environmental Scientist, Project Consultant and Ambassador for

The Grove: Leading. Learning. Living.

WASTEWATER

TREATMENT & REUSE

ENVIRONMENTALLY SUSTAINABLE DESIGN (ESD) FACT SHEET 6VERSION 1/MARCH 2011

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Waterless urinals at The Grove for yellow water collection prior to treatmentand reuse (via irrigation dosing)

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8/9/2019 The Grove Wastewater Reuse Fact Sheet

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THE GROVE — ESD FACT SHEET 6: WASTEWATER TREATMENT & REUSE pg 2

Changing weather patterns (reduced rainfall and extended periods of drought), increasingdemand and inefficient water management means that less water must start going further. Weneed to face up to the reality that water is a scarce and valuable resource, and if we want toensure a more secure supply into the future, we must both diversify our water sources plus usewater more carefully.

Treating and reusing our wastewater for landscape irrigation (as well as certain non-potableindoor applications) is one of several smart ways of reducing pressure on high-quality watersupplies. Studies around Australia have shown that there is strong public support for the reuse ofwastewater and that it can lead to significant savings of water, energy and money. A decentralisedonsite approach can be part of the solution – it often makes more sense as wastewater can besafely reused locally with much less pumping/energy consumption than remote end-of-pipecentralised systems.

WHY ISWASTEWATER TREATMENT & REUSE 

IMPORTANT?

 Australia is the driest inhabited continent, yet our per capita water

consumption is one of the highest in the world. At present, rather than

adopting a ‘fit-for-purpose’ approach (using different sources and varying

quality of water for different applications), high-quality drinking water is

used for practically everything – including watering the garden and flushing

the toilet.

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Wastewater tank arrangement at The Grove

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THE GROVE — ESD FACT SHEET 6: WASTEWATER TREATMENT & REUSE pg 3

The integrated wastewater system at The Grovehas been designed to supply a proportion oflandscape water demand for irrigation (i.e.substitute bore water); effectively manage andutilise nutrients from the wastewater streamfor landscape plant requirements; rechargethe shallow aquifer to offset bore water usefor seasonal landscape demands that exceedavailable wastewater volumes; and reducevolumetric and pollutant concentration loadingson the mains sewer.

The design of the system developed afterwater budget modelling was used to deliver anoptimised outcome for this specific project.The modelling analysed the anticipated rangefor the volumes of different wastewater streamsgenerated from the buildings (based on lowand high occupancy rates and different waterfixtures). Given the wastewater loads at TheGrove can be fluctuating and highly variable(it is a public daytime facility), a key design

parameter was to ensure that overflow anddiversion to the mains sewer is provided at allcritical points – thereby minimising the risk ofoverloading any of the treatment systems.

It is estimated that the wastewater systemat The Grove will reduce the draw ongroundwater that would be used for irrigationby approximately 700,000L each year. A majorinnovation is that the system provides for onsiteseparation, treatment and reuse of differentwastewater streams, namely greywater(showers and hand basins), brown water (toiletsas well as kitchen) and yellow water (urinals).

Greywater

The greywater system consists of a simplesedimentation tank followed by secondarytreatment in a pump-out tank. Before thegreywater is discharged it undergoes ozonation(a treatment process that destroys bacteriaand other microorganisms through an infusionof ozone). Once treated, the greywater is thenpumped to the onsite landscape (directly to theplants’ rootzone) via substrata (under mulch)drip irrigation.

When viewed in conjunction with the brown

water and yellow water system, the approachadopted for greywater at The Grove allowsmaximum utilisation of the available greywaterwith minimum operation and maintenancerequirements.

WHAT HAS BEEN DONEAT THE GROVE TO SHOWCASE

WASTEWATER TREATMENT & REUSE? An innovative wastewater system has been incorporated into The Grove as

 part of achieving a key objective of the three Councils to provide a tangible

real-life example of sustainability in action.

Brown water

The brown water system consists of a pre-treatment Biolytix biogrinder (BG4000PAV)and two Biolytix filters (BF63000PAV). TheBiolytix is a low energy, low maintenanceaerobic treatment unit that uses biological,

chemical-free processes to convert sewage andwastewater into high-quality irrigation water foronsite reuse. The system employs a number ofstaged filters and billions of micro-organisms toseparate solids and liquids, break down organicmaterial, nutrients and chemical compounds,and treat the residual water to a high standardthat is suitable for irrigation.

 The inclusion of a pre-treatment biogrinderensures that the volume of incomingwastewater is matched to the treatmentcapacity of the system. The biogrinder receivesall brown water and then distributes theincoming flows evenly between two Biolytixfilters in parallel. In the event of flows greaterthan the peak daily allowable load these areautomatically diverted to sewer. This designeffectively means that the filters are onlyrequired to treat a maximum defined volume ofwastewater with any excess or peak flows beingdiverted directly to sewer.

Yellow water

The yellow water system represents state-of-the-art source separation of wastewater byincorporating waterless urinals. These collecturine separately so that it can be stored for 6months (for treatment purposes) prior to use.The intention is to also include urine divertingtoilet pans for the female toilets in the future(pre-plumbing has been installed to allow thisonce the proposed overseas toilet systemshave been granted the WaterMark certificationrequired in Australia).

After collection, the urine is stored in 3 x 10kLin-ground concrete tanks and cycled in sucha manner to ensure a minimum of 6 monthsstorage before discharge to irrigation. Therich mix of nutrients in the treated (sterile) endproduct can then be dosed as required into the

various subsurface and substrata irrigation linesas a fertiliser for plants.

.

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THE GROVE — ESD FACT SHEET 6: WASTEWATER TREATMENT & REUSE pg 4

It is important to note that you can only installa greywater system that has been approved bythe WA Department of Health. The approvedsystems range from simple direct diversionmodels that provide basic filtration prior toirrigation, through to more elaborate systemsthat treat and disinfect the greywater.

As greywater can contain pathogens (diseasecausing organisms), it is important to followsome simple practices to eliminate any healthrisks. The greywater must be applied beneaththe ground via a subsoil trench or purplecoloured dripline covered with 100mm of

mulch (unless the greywater is treated anddisinfected). This reduces the scope for humancontact and minimises the potential health risksassociated with greywater systems.

You will need to lodge an application andreceive approval from your Local Governmentbefore installing your greywater system, and alicensed plumber must undertake all changes tothe house and sewer plumbing.

Greywater systems vary greatly in costdepending on the type of system you install. Asimple gravity fed direct diversion system will

cost around $800, mid-range pumped systemsrange from $2,000 - $8,000, while a top-endtreatment system (which allows the greywaterto be safely stored in tanks for an extendedperiod of time as well as used for above-groundirrigation) can cost in excess of $10,000. TheFederal Government greywater rebate of $500only applies to these more expensive treatmentsystems.

WHAT CAN YOU DO AT HOME?

While a fully integrated wastewater system like what is being showcased at

The Grove is not feasible at the household scale, you can however install a greywater system for your own home. On average each person in Australia

 produces about 100 litres of greywater per day. Instead of simply wasting

this resource, you can divert the greywater for garden irrigation.

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Greywater system and lilac dripline in ahome garden

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Reusing greywater to irrigate your gardenwill enable you to:

 • Reduce your mains waterconsumption for garden irrigation

 • Save money on your water bill • Have an alternative source of

irrigation during water restrictions

 • Reduce the energy used in pumpingwastewater from your house (hencelowering greenhouse gas emissions)

 • Help in conserving Perth’s scarcedrinking water reserves, therebyreducing the costs and pressure onexisting or new water infrastructure

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THE GROVE — ESD FACT SHEET 6: WASTEWATER TREATMENT & REUSE pg 5

Living Smart/Perth Solar City Program:Greywater Reuse How to Guide

Department of Sustainability, Environment,Water, Population & Communities: GreywaterReuse Fact Sheet

Your Home Technical Manual: WastewaterReuse Fact Sheet

WA Department of Health: Greywater ReuseFact Sheet

WA Department of Health: List of ApprovedGreywater Systems

Water Corporation: List of Waterwise Plumbersfor Metropolitan Perth

Save Water Alliance: Greywater ReuseInformation Resources

Living Greener: Household GreywaterInformation

FIND OUT MORE ONGREYWATER REUSE FOR YOURHOME

WA Department of Health: (08) 9388 4999

WA Department of Water: (08) 6364 7600

Water Corporation:  13 10 39

Department of Sustainability, Environment,Water, Population & Communities: 1800 218 478

Content - Josh Byrne & Associates Graphic design - Oakridge Communication Group

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  Further Information   Relevant Organisations

Please visit www.thegroveprecinct.com to download an electronic version of this fact sheet with

hyperlinks to the above online resources.

The Grove, an environmental sustainability pioneer.