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Grey Water Recycling Systems

By: Dr Gareth Evans - Updated: 9 Jun 2010 | comments*Discuss
 
Recycling Systems Grey Water Recycling

With greater extremes in our weather patterns predicted as a result of climate change and Britain’s annual water demand already growing, the prospect of sporadic water shortages in the future looks increasingly likely and interest is growing in all forms of water recycling systems.

Rain water harvesting is one solution which has been on the receiving end of a growing amount of interest over recent years, but the lesser known grey water recycling could also have its role to play in helping to reduce our use of treated water from the mains.

What Is Grey Water?

Grey water is the description given to the waste water from baths, wash hand basins and washing machines – but not kitchen sinks or toilets. Typically lightly contaminated with a whole range of substances including grease, detergent, soap and bacteria, grey water can be reused, but it cannot be stored for any length of time or it will begin to smell – meaning it has to be used quickly, once collected. Bath and shower water tend to be the best candidates for recycling systems since any contaminants they contain generally tend to be fairly well diluted.

Improving Quality

The quality of the grey water available for reuse entirely depends on what you put in it in the first place. For top quality grey water recycling it is a good idea to move to natural, biodegradable cleaning products – and fit some kind of a filter to separate out hairs and any other particles that might be present in the water before use.

Even a simple mesh strainer on the plughole will prove helpful to sieve out undesirable bits, but for recycling systems using large amounts of grey water, it’s probably worth installing an additional sand filter to reduce the likelihood of harmful chemicals accumulating.

Using Grey Water

Probably the best use of grey water is in the garden. However, since many of its common contaminants including soap, salt and grease, can cause problems, the less contaminated the water is, the better. Although using grey water for irrigation has obvious benefits, there are a few precautions that need to be taken.

It should only be used on ornamental plants, or well established vegetable plots and even then direct contact between the water and the plants themselves is best avoided.

Using grey water in this way is a very cheap approach to reducing your mains demand, involving little more than a few buckets to transfer your used bath water to the greenhouse or garden. It is possible to use grey water for other domestic purposes – including toilet flushing and washing cars – but to do this inevitably requires rather more sophisticated recycling systems.

The technology behind them is currently very young – and consequently rather expensive. In addition, many of today’s commercially available grey water recycling systems require disinfectants which are typically energy intensive to make, while independent studies suggest that running costs add up to more than using the mains supply.

At least for the moment, it seems that these systems are not likely to be appropriate for most average British households, nor particularly eco-friendly to operate. However, future developments coupled with growing pressures on water resources may eventually change this in time.

Whether you opt for a full blown diversion kit, or use the simpler, bucket-for-your-bathwater approach, recycling grey water is something to think about. While it may not make a huge difference to you household bills, used sensibly and carefully, it does represent a way to get double use out of one of the planet’s most precious resources.

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