University of Cambridge installs largest water recycling system in the UK
The University of Cambridge, in partnership with local water company Cambridge Water, are putting in place the UK’s largest water recycling system at the 150 hectare North-West Cambridge Development. This extensive system will involve the recycling of rain and surface water, which will be used for flushing toilets, watering gardens and cleaning clothes. A separate system will supply high quality water for drinking, cooking and bathing. Construction consultancy Turner and Townsend are managing the project for the University. Cambridge Water’s sister company, Integrated Water Services (IWS), are constructing the water treatment works. Both the latter two companies are owned by South Staffordshire Water PLC.
More Cambridge housing needed, but water supplies limited
Cambridge is one of the UK’s high growth areas. However, as employment opportunities have brought more people to the area, a serious housing shortage has resulted, with rents and mortgages becoming unaffordable to many. Many workers have to live far away from the city, commuting over long distances along congested roads. One new development is the University’s North-West Cambridge Development, which will eventually incorporate 3000 new houses, along with accommodation for 2000 postgraduate students, a supermarket, hotel, shops, a doctor’s surgery, a community centre and a primary school. The school took its first pupils in September 2015. The first phase of the development is due to be completed in 2017.
However, Cambridge is also one of the driest areas in the UK. Local water is extracted from nearby boreholes, but the supply is not unlimited, so any substantial new developments need to incorporate water-saving measures.
Largest water recycling system in the UK will almost halve water usage
The new recycling system involves directing rain and surface water into artificial lakes, where natural filtration through reed beds occurs. Refiltration, sterilisation with ultraviolet light and chlorination take place, before the water is reused for toilets, clothes washing and gardening. The lakes will also reduce the risk of flooding in downstream areas, by acting as buffers for rainwater. This is an example of a sustainable drainage system (SuDS).
Various efficient plumbing fittings, for example aerated taps and showers, are to be incorporated into buildings in the new development. It is estimated that water usage will almost halve, reaching an average daily level of 80 litres per person (the UK average is currently around 150 litres per person).
SuDS systems and water recycling
Sustainable drainage systems (SuDS) are designed to mimic the flows of water on undeveloped land, releasing rainwater slowly to watercourses, so that they are less likely to be overwhelmed. Traditional drainage systems, involving hard pipes and culverts, lead to the rapid deposition of water in watercourses when rainfall is high. High rainfall may also cause pollution, particularly if water overflows into the foul sewage system. SuDS can also improve water quality in downstream watercourses, as vegetated swales and ponds can help remove pollutants. Retention systems, such as retention ponds (stormwater ponds) can hold excess water and help prevent floods. However, such retention systems can also be used as a source of recyclable water. The Cambridge development, as the largest water recycling system in the UK, should showcase the use of such systems, and be a template for the incorporation of large-scale water recycling in other new developments.
North West Cambridge Development Website, ‘UK’s largest water recycling system secured.’ http://www.nwcambridge.co.uk/news/uks-largest-water-recycling-system-secured
British Geological Survey Website, ’What are SuDS and how do they work?’ http://www.bgs.ac.uk/research/engineeringGeology/urbanGeoscience/suds/what.html
Cambridge Water Website, ‘How much water do you use?’ http://www.cambridge-water.co.uk/customers/how-much-water-do-you-use