DRINKING WATER supplies should be supplemented with treated sewage effluent as a means of averting a national water crisis in the UK, the ICE has said.
In its annual State of the Nation report, the ICE recommends that effluent be put back into rivers and reservoirs at suitable locations for extraction to municipal supply.
'It is a resource that is not really being used at the moment.
It is a relatively untapped way of providing drinking water to meet growing long-term needs, ' said ICE water board chairman John Lawson.
However, Lawson shied away from companies treating the effluent at wastewater treatment works and putting it directly into supply.
'I think that is probably a step too far at the moment, ' he said.
'We are suggesting that rather than discharge effluent downstream (where it then flows out to sea) it is pumped into water courses upstream where it can then be put back into supply, ' he explained.
The suggestion got a mixed response from the water companies. The industry representative body Water UK criticised the ICE for labelling effluent reuse a 'radical solution'.
'The water cycle means that some of the water abstracted for public supply has been treated to a high standard and returned to the environment, ' it said.
'Following time in rivers or reservoirs, the water may be abstracted again under carefully managed circumstances for public supply use.
'There is no intention or need to change the current policy on effluent reuse, ' Water UK added.
Mayor of London Ken Livingstone is keen on effluent reuse. During the recent public inquiry into Thames Water's desalination plant he urged the company to take the lead in developing the technology.
'Effl uent reuse, which would cost a similar amount to a desalination plant but be less harmful to the environment, ' he said.
Thames Water is carrying out an effluent reuse pilot project at Deephams treatment works in Edmonton, north London.
The company is only producing 1Ml per day from effluent and is not yet putting it into public supply.
'The capability exists, but the matter of public perception still has to be dealt with, ' said a spokesman.
The Environment Agency backed the strategy, but warned of potential environmental impacts. Head of water resources Ian Barker said: 'Effluent reuse is a sensible option for water companies to consider when they need new sources of water.
'It is particularly good where water would otherwise be discharged into the sea.' But he added: 'Inland discharges from treatment works often support summer river flows and the removal of this source of water could damage the environment.' In its report the ICE called for the UK Environment Agency to take a stronger lead in water resource planning.
However, Barker said: 'It is up to the water companies to decide how they intend to plan for their customers' needs for the next 25 years.'
At Essex & Suffolk Water, reuse of effluent is supplying customers with up to 40Ml per day. As a water-only company it is using effluent from neighbouring sewage service provider Anglian Water to supplement supplies.
'We believe this is the only scheme of its kind in Europe, perhaps even in the world, ' said a spokesman.
'Effluent from Anglian Water's Chelmsford plant is taken from the discharge pipeline and put into our water treatment plant. Once it has been through the works at Langford it goes into the River Chelmer and this dilution further improves quality levels. It is then pumped to Hanningfield Reservoir in Chelmsford where it is put through another water treatment plant and into supply.' 'We are licensed to use up to 40Ml per day, but we operate at 30Ml per day. Usually we operate through April to October, but in the current challenging resource situation we expect to be doing this all year round, ' he said.
The scheme started in 2003 and cost $25M to build. 'It is working effectively and efficiently, and could be replicated, but it does require huge consultation with bodies such as the Environment Agency and the Drinking Water Inspectorate.'