LA: To evaluate how water supply and demand can be managed sustainably By Adrijana, Stagg and Leon.

Key Point! Identify the benefits AND problems of greywater.

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What is greywater? Greywater is wastewater generated from bathrooms (shower and basin), laundries and kitchens, or those components of household sewage that DO NOT come from a toilet, urinal or bidet.

What does greywater contain? The characteristics of greywater produced by a household will vary according to the lifestyle, health status and water usage patterns of the occupants. Greywater contains micro-organisms, chemical contaminants (in particular nutrients and salts) and physical contaminants (such as dirt, lint and sand).

The main advantages of utilising greywater are… Reducing your potable water consumption [environmental/economic] Reducing the amount of sewage discharged to the ocean or rivers [environmental] Reducing your water bills [socio-economic] Irrigating your garden during drought periods [environmental]. Groundwater recharge [environmental] Plant growth [environmental] Increased awareness of and sensitivity to natural cycles [social/environmental].

Main disadvantages of the use of greywater include… The potential for pollution and undesirable if the greywater is not reused correctly [environmental]. Undesired health effects could be produced if the greywater is not produced and utilised correctly [social]. Initial cost of a greywater system and plumbing requirements [economic]. Ongoing maintenance [economic].

How can greywater be used? UNTREATED Sub-surface irrigation (irrigation buried at least 10 cm below the surface of soil or mulch). TREATED Sub-surface immigration again Surface irrigation Toilet flushing Washing machine use.

Why use greywater? Greywater reuse is a part of the fundamental solution to many ecological problems. The use of greywater is becoming widely utilised around the world. US Green Building Council, the City of Santa Barbara, CA, Oregon ReCode, SLO Green Build are among those organizations which independently chose greywater standards as the technology with which to launch their programs of regulatory reform.

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