Water Recycling
Rainwater and grey water are both important resources for increasing water efficiency.
Rainwater
Rainwater harvesting is the collection of filtered rainwater from roofs and its storage, for re-use as and when required. Washing machines, toilets and gardens account for around half of domestic water usage. By using rainwater, savings can be made and the strain placed on over utilized mains supply can be reduced.
Key advantages
- Up to 50% of mains water can be replaced by stored water.
- Ideal water source for remote areas.
- As part of a storm-water management scheme it reduces runoff and can control the flow-rate off site;
- Adds value to the property
According to the Chartered Institution of Water and Environmental Management, "Where there is negligible potential human contact the rainwater will usually only require coarse filtration to prevent leaf litter, debris and small animals entering the system."
Rainwater capture can also work when integrated with a drainage sewerage system.
Grey water
Greywater is defined as water that has already been used within the property, although this does not include toilet water. Greywater can thus account for between 50-80% of recycled "waste" water. This may be reused for other purposes, and is ideal for large landscape projects and gardens.
According to the Chartered Institution of Water and Environmental Management, "Unlike rainwater, greywater requires filtration to remove hair, skin and soap products from the water and chemical or biological treatment prior to reuse." They stress the need for adequate system maintenance to prevent health hazards, and their website includes a useful diagram explaining the dimensions of the potential risk, which could be useful for risk assessment of a greywater system.
Chartered Institution of Water and Environmental Management Rainwater Harvesting The Environment Agency |
