Grey water: the biggest barrier to its use may well be the name. So reckons Paul Williams, managing director of Water Dynamics, Britain’s best known grey water recycling systems maker. “When you hear the term grey water, images of filthy waste from washing machines spring to mind. But the reality is that grey water is actually as clean as the water you would find in a swimming pool.”
Water Dynamics has been producing grey water systems since 1995, and their business has just taken a stride forward by achieving WIMLAS accreditation - something the NHBC and Zurich are now insisting on if grey water systems are to be included in their cover. After attracting interest from the self-build sector and from a few housing associations, Water Dynamics now finds itself with a raft of blue-chip customers, including Crest and Westbury. Planning departments in the South East are said to be looking more favourably on development proposals that include some form of water demand management.
The attraction of using grey water recycling to do that is simple. Unlike the alternative technique of rainwater harvesting, grey water recycling promises to match supply with demand, therefore greatly reducing the scale of the water storage required to make it work. This in turn reduces the installation costs to under £1000 for a single new build unit.
Most grey water recycling systems work by taking water draining from the bathtub, washbasins and/or showers, filtering out the suspensions and storing it in a bath-sized holding tank. This water is then pumped up into a header tank in the loft where it is treated with disinfectant and this tank is used to provide water to the WC cisterns.
However, two early trials of the Water Dynamics system have shown that this emerging technology has some way to go before it can deliver water savings seamlessly. The Environment Agency has recently published its report on a trial on 10 homes fitted with early Water Dynamics systems. And Essex & Suffolk Water Company is in the process of evaluating data collected for it by the BRE on three homes in their area which were metered and monitored weekly for a year. Both trials confirmed that significant savings were achievable, but also uncovered an alarming number of system failures.
Problems encountered included airlocks, blocked filters, chemicals running out and pumps malfunctioning. When breakdown occurs, the system automatically switches to normal mains supply, so in many cases, householders were unaware that the grey water system was not working.
Water Dynamics is not disheartened by these results. The trials were of huge benefit to the company, and have served to improve the product. Williams comments: “We have changed the pump, introduced a warning light system and switched to a different gauged filter. With something as new as grey water, there are no textbooks so, inevitably, a lot of it is developed by trial and error.”
Water Dynamics is not ploughing a lone furrow. Other system makers include Aquasaver, Water Matters and Merpro. Water Matters has worked on Integer projects, Merpro plans to launch a more heavily-engineered product at the end of this year, and Anglian Water and Beazer Homes have joined forces to promote Waterwise - a water recycling treatment plant suitable for whole housing sites, rather than individual homes.
Unlike many emerging technologies for the future home, the UK is not playing catch-up with grey water. Although rainwater harvesting is widely practised elsewhere, the reuse of washing water is still in its infancy and teething troubles are to be expected. What emerges from the first few years experience is that the reuse of grey water may yet have a significant impact on new housing, but single house units are unlikely ever to be a fit-and-forget solution.
Source
Building Homes
