Water recycling

Saving water

Living in the UK we get used to rain!  So living in such a green and plush country we often forget about the importance of water conservation until the next hosepipe ban prevents us from washing our cars or watering our flowerbeds.  

So apart from the inconvenience of a water shortage, you may be one of the 20% of householders who have a water meter fitted and for whom saving water could even save you money.

It also displaces a large proportion of the water that would otherwise be provided by the mains supply - thus reducing overall water supply costs.

So what are your options and how much can you expect it to cost?

The two main methods of recycling water is by harvesting rainwater or reusing  grey water.

Rainwater harvesting

• Safety
• How much does it cost?

Greywater recycling

• Safety
• How much does it cost?
• Is it green?

Other options

Rainwater harvesting

At a very simple level, water can be collected from the downpipes running from your rooftop into the drain and collected in a water butt, allowing you to fill a watering can and water your garden, or to have it fed into a more sophisticated irrigation system using filters to catch any debris before it is distributed around the garden. If such a system is not supplemented by mains water (some more complex systems have a mains backup) then it is not subject to the hosepipe ban.

The next step in sophistication (and cost) is a system that feeds the water into an underground storage tank using debris filters and water smoothing inlets to ensure that rainwater flowing into the tank doesn’t mix up the sediment on the bottom of the tank. This water can then be pumped through designated pipes to supply washing machines and toilets.

Safety

It is important to note that rainwater collected using these systems are not treated unless a specialised sterilisation system is installed, and is therefore not suitable for cooking, drinking or bathing.

However, as this rainwater is stored below 18˚c and is kept well oxygenated there is little chance of Legionella and other harmful bacteria growing.

How much does it cost?

Between £2000 and £3000 for a good quality domestic system depending on the  of the tank used. There is generally a choice of three tank sizes; 1300L, 3500L and 5000L.

Greywater recycling

Greywater is waste water generated from domestic processes such as dish washing, laundry and bathing and  comprises 50-80% of residential wastewater and can therefore have a significant affect on water usage.  Greywater recycling involves collecting waste water, treating it and then reusing. Again, this water is not suitable for drinking or cooking purposes.

This reuse of water reduces the load on valuable ground water reserves, and also reduces the drainage burden because the water is processed within the confines of the house.  After processing, slightly polluted water from the bath, shower and washbasin is reused in the house for flushing the toilet, watering the garden or for cleaning purposes.  If the water is used to water the garden, ensure that you use eco-friendly washing powders (because bleach can affect plants and wildlife),  and only water established plants.

Safety

Greywater is warm water when it is stored and therefore requires treatment using 'physical' or 'biological' systems. Physical treatment is suitable for small scale systems using filters and chemicals to prevent bacteria from growing. Biological treatment is used for larger systems and is based on the systems used to process sewage.  Some systems use a combination of both systems.

This water is not suitable for cooking, drinking or bathing.

How much does it cost?

A system like the AquaCycle 900 working without the use of chemicals and purely biomechanically will produce water which meets the strict E.U. Directive for clean Recreational Water and cost about £4100 for a standard system.

Is it green?

This is a complex issue. The water saved can be significant, however, energy and chemicals are required to clean the water and this may cancel out the benefits of the system.