Can large-scale water recycling work in England?
Large-scale water recycling technology could provide a solution where there are water constraints in areas of new urban development. However, the English water industry would need to adopt a more flexible approach to its structure and standards first, says Bob Sargent.The north-east Norwich growth area - which includes the Rackheath eco-town - is planned to provide upwards of 16,000 homes and associated housing in Norfolk. The area is in one of the driest parts of England and a water cycle study is being undertaken to establish the most sustainable approach to take.
The catchment area is in the Broads and it is therefore also a highly sensitive environment. There are several national and internationally designated wetland areas downstream of the development area, including a Ramsar site. Being in an intensive agricultural area these sites are already impacted by over-enrichment and there is limited scope for further discharge of nutrients.
The standard solution to this problem would be to import water from outside the catchment and pump treated effluent back out to less sensitive watercourses. Whilst feasible, this approach would be capital intensive, inflexible, requiring large-scale infrastructure development before the development could start, and have a very high carbon footprint: not a desirable solution for an eco-town, and not one the developers are keen to employ.
So is there an alternative? Recent development in Australia, where similar water constraints exist for new urban extensions, shows that there is, and that the technology might be easily applied in Norwich and elsewhere in England. The challenge is to make the technology work in an English context and with the administrative framework that exists in the country.
An example site is Fyansford, a new residential development located west of Geelong in Victoria, Australia, which involves more than 2,000 dwellings to be constructed over the next 10-15 years. The integrated water management scheme includes constructing a 660m3/day wastewater treatment plant (WWTP) as a first stage towards providing sewerage and recycled water services for this development.
The WWTP is capable of treating wastewater from the development to Class A+ standard - an Australian classification for recycled water for unrestricted urban reuse such as fire fighting, toilet flushing, washing machines and urban irrigation.
Another development, near Creswick, in Victoria, Australia comprises a golf course, 144 room hotel and 250 houses; the first stage was commissioned in 2008.
The integrated water cycle scheme for this development involves maximising the use of the local water resources for non-potable demands, thus reducing pressure on potable water supplies. It includes treating wastewater to Class A standard for irrigating the golf course and desalinating local groundwater for urban non-potable use in a separate recycled water supply reticulated system.
Stormwater harvesting is used to supplement both the reticulated recycled water supply and the golf course irrigation system. Both these sites demonstrate that rainwater harvesting and recycled water can be supplied at community level and doing so provides great flexibility as large infrastructure investment is not required at the beginning of the project.
Could it work in the UK? There is no reason why the technology should not be readily transportable, but community harvesting and recycling of water has not been yet been undertaken in the UK and there are difficulties to overcome. Firstly, the UK water industry is heavily regulated and geared towards traditional, large scale water companies. Supply of water to the public can only be carried out by a statutory water undertaking, regulated by Ofwat. Obtaining a licence to act as a water undertaking is an onerous process and few licences have been granted since the original privatisation of the water industry in 1974. If community recycling of water is to become a reality, small purpose-made water undertakings will be required and a ready means of creating them.
Secondly, resupply of treated sewage effluent into people's homes, even if only for non-potable uses, would be considered a new departure for the UK. Treated effluent is currently supplied for potable uses in many areas, of course, but only after the effluent has passed along a length of river first. Many inland water abstractions are downstream of effluent discharges, but that section of river between them creates a break in the public's eye. Without that river stretch some public acceptability issues are likely to be encountered before treated sewage can be supplied to homes.
And lastly, the UK lacks standards for harvested and recycled water for operators to work to. Users also do not have a clear idea of what recycled water could potentially be used for, or even if it is safe to have in the home. Simple, use-related standards would be a big help in the promotion of recycled water.
The technology already exists and works elsewhere. If it is to be used anywhere in the UK in the foreseeable future then Rackheath eco-town, with its water constraints and willingness to adopt truly sustainable measures, will surely be the site. The English water industry needs to respond to the challenge first, though, and adopt increased flexibility in the both its structure and its standards.
Bob Sargent, Environmental Advisors LLP