Greywater Reuse Systems

•   There is an increasing awareness of the need to recycle and reduce waste; however, there is also little evidence of any real desire in the community to reduce the level of consumption.
• We all need to treat and recycle waste to prevent pollution, and to conserve and re-use our limited resources.
• Each of us needs to adopt reuse strategies for a sustainable future.
•  Generally, the community supports greywater reuse, and the interest in reuse schemes is high. However, the initial capital outlay to install reuse systems is also high and this prohibits the implementation of reuse systems.
•  Each of the greywater systems discussed here have specific advantages and particular applications. These types of systems have been approved because of the intention to reuse wastewater to irrigate garden areas. However, the use of greywater to provide effective irrigation is limited, as subsurface piped trench systems generally do not supply an adequate or consistent watering regime for plants. Dripper systems are now becoming more popular, and may be better suited for plant watering.
•  On-going monitoring of greywater reuse systems will help determine their effectiveness to save water, reduce nutrients and pathogens, and irrigate plants.
• Global warming of 0.7C and sea-level rise of 17 cm since 1900
• Past 11 years are amongst the 12 warmest years since 1985
•  Increase in extremely high temperatures, decrease in extremely low temp
•  More intense rainfall.
• More intense cyclones
•  Oceans more acidic due to higher carbon dioxide
• Glaciers and artic ice extent have decreased
• Shift in animal and plant locations and behaviour 

• Global average 1200 m3/person/year   
• Vegetarian 600 m3/person/year 
• Meat diet 1800 m3/person/year                                

•    beef            -  15 m3 
•   chicken         -  5 m3    
•   grain            - 1.5 m3  
•   fruit/veges   - 1 m3   

• Rainwater tanks are a more cost-effective alternative to other water saving measures.
• The study conducted by economists found that rainwater tanks are more than five times as energy efficient as a desalination plant per kilolitre of water produced.
• If governments rolled rainwater tanks out to 5 per cent of households in Sydney and south-east Queensland, big water projects like dams could be delayed for up to a decade.
• Nearly 40 per cent of Adelaide households have installed them, but only 5 per cent of households in Perth, Melbourne and Sydney have them.
•  Australian average 17%.   

• It is estimated the average application of 10 mm of water to soil for irrigation uses: 

  • 10 L over 1 square metre.
  • If dripline 5 L/hr, drippers @ 300 mm and 300 mm spacing (ten drippers) = 12 minutes.
  • If dripline = 2 L/hr, this equates to 20 mins watering.

For 10mm of rain fall

•     200sqm roof = 2,000 litres X 80% collection / rain bounce
•     = 1,600 litres water stored 

• Toilet  - 4 litres / flush – 140 litre / week
• Laundry 80 litres / wash  - 320 litre / week
• Total Usage = 460 / week = 5 weeks storage after the last rain  

Five Star Plus- (new changes to the building code) 

•  Stage 1- September 1 2007.  -  Water efficient fixtures, energy-efficient HWS.
• Stage 2 - September 1, 2008 - Provision for alternative water sources and greywater systems. 

Five Star Plus Rainwater -  Criteria 4 – provision for future connection

• All toilets and washing machine/s to be connected to alternative water supply.  Typically, install a dedicated ring line linking these fixtures and then connect back into     scheme.
• Plumbed so that new pipes, in any future connection, do not have to be laid.   Pipes are pre-laid and connected outside building so that alternative water supply can    easily be installed at a later date.
• Bore water can be used, if appropriate.    Quality of bore water is very variable and may not be suitable in all areas. 

Criteria 6 – to apply in all new homes in Perth Metropolitan / Peel scheme water areas only.

• Any home with more than two showers or toilets must be connected to alternative water supply.  This will apply to 5% houses with more than 2 showers and 7% houses with more than 2 toilets.
• Any additions to house will need to be connected to alternative water (but not existing house fixtures).  

• All shower, bath, laundry trough and washing machine drains connected to greywater diversion device. 
• Plumbed to enable future connection to a greywater reuse system.   

• Above Ground  700 litre - $ 450 = $ 0.65 / litre2500 litre - $ 750 = $ 0.30 / litre 
• Slimline  - Above Ground3000 litre - $ 1650 = $ 0.55 / litre 
• Underground Poly – Pedestrian traffic  - 1800 litre - $ 1000 = $ 0.55 / litrePoly – Heavy Duty traffic  - 1800 litre - $ 1500 = $ 0.83 / litre