Focus on grey water recycling
What is it, how does it work in practice – and why isn’t everyone doing it?
Water is an increasingly precious resource. Growing populations need more of it but climate change and over extraction means there is less available. Hosepipe bans are a short-term, reactive measure by water utility companies to combat water shortages. But if we reuse water from the wastewater from our baths and showers to flush the loo and other purposes, it will ease pressure on resources in the future.
What is greywater recycling?
‘Greywater’ is the name given to the stuff that drains from showers, baths, sinks and washing machines probably because of its cloudy appearance. It accounts for between 50 to 80% of a typical household’s wastewater volume. This wastewater has high potential for reuse but in most existing homes in the UK, plumbing directs it all down the sewer. Environmentalists say this is, well, a waste and a missed opportunity.
Separating the greywater from sewage from toilets, often described as ‘black water,’ allows homeowners to capture and reuse it for purposes that don’t require pure drinking or ‘potable’ quality water.
Grey water recycling systems collect, clean and re-use this slightly contaminated water for flushing toilets, clothes washing machines, garden irrigation and even topping up swimming pools. But while you’ll find greywater recycling systems in a few forward-thinking council housing estates, apartment buildings and hotels, it’s rare to find a homeowner in the UK with the technology despite a growing number of manufacturers supplying the market. Why is this?
The pros
There are many pros to grey water recycling. You can reduce your mains water consumption, lower your wastewater emission and (if you are on a water meter) save money on water and energy bills. You can also reduce your carbon footprint because less water needs to be pumped to and from your home and less water needs to be cleaned in wastewater facilities.
There are wider environmental benefits, too. Grey water recycling can reduce the strain on water sources and provide a reliable source of irrigation water during times of drought. Unlike a rainwater harvesting system, which relies on rainfall, greywater is available in plentiful supply every day.
And the cons …
There are, however, some cons. Greywater needs to be handled correctly and at present that makes it expensive. The problem is the need to store contaminated water that may contain bacteria which will start to breed and smell if not treated properly. So, you need to treat it, which would normally involve chemical treatment, filtering or sterilising with ultraviolet light. The technology is more cost-effective if it’s shared, for example in an apartment block or neighbourhood.
Typically, domestic water treatment systems are bulky tanks that need to be put in a garage with filters and membranes that often get dirty and clogged, so need regular cleaning and maintenance which means ongoing costs. Most also add chemicals to the water treatment process, making it less eco-friendly. Additionally, grey water can contain other pollutants, such as detergents and cleaning products, that can have a harmful effect on the environment if not properly filtered.
Plus, there are concerns over the hygiene and safety of reusing grey water. People may not like the idea of washing clothes in water previously used for cleaning dishes, but these are the kinds of mental hurdles we are going to have to get over to live more sustainably.
Greywater recycling systems
Various companies that specialise in water management and treatment offer grey water recycling systems in the UK, including Aquacell Water Solutions and Aquality. The devices vary in size and price.
Hydraloop, a Dutch invention, has won lots of positive press coverage. The company says its unique water treatment technology means “no filters, membranes or chemicals.” The devices clean the greywater in six processes, beginning with sedimentation and ending with UV disinfection, so are low maintenance. They are also self-cleaning.
Preparing the plumbing, says the company, “is not difficult”, whether you are planning a new build or retrofit of an existing property. An accompanying smartphone app lets you see exactly how much water you recycle and save per day, week or month. If there is a problem, it automatically switches to back-up water and sends a warning message to you and your installer.
The technology has the potential to recycle up to 95% of your shower and bath water as well as water from washing machines. Depending on the model, you can also collect and clean condensation water from the tumble dryer, heat pump and air conditioning units.
The company says the treated and disinfected water is suitable for re-use in loos, washing machines, pools and garden irrigation. This reduces both mains water and sewage run-off by 45. Prices vary from online retailers for the Hydraloop H300 (300 litres) between £4,250 - £5,549, excluding installation.
A cheaper option is to install a smaller tank that just stores your bath and shower water and uses it solely to flush the toilet. In the UK, ReAqua sells such a system. The tank (100 litres) is compact, fitting into a cupboard. A revised plumbing set-up takes all the wastewater from baths and showers and redirects it through a filtration system to treat it with disinfectant. The treated water is then piped on to flush all the loos. Expect to pay around £1,000 for a basic system and up to £300 to install it in an existing bathroom. It’s important to use a competent local plumber to install the pipework.
Grey water recycling has yet to catch on in the UK. Many people may simply be unaware that it is an option and its potential benefits. But another reason is that installing a whole-house grey water system can be expensive. Of course, if you have a water meter, there are future potential savings though the payback period could be lengthy.
But with climate change and the increasing pressure on the UK’s water resources, its time for the government and water companies to invest in the development of grey water recycling technology and raise awareness of its benefits. Water is a precious commodity. Greywater recycling offers the chance to cut household water use by up to a half.