Campaigners warn against Thames Water’s £250m effluent ‘recycling’ scheme

Thames Water is facing a public backlash over a multimillion-pound water “recycling” scheme promoted as a solution to tackling climate crisis-induced droughts.

The technology involves using effluent from sewage treatment works, putting it through a further layer of treatment and releasing the treated water into a river, in order to replace the same amount of water that is abstracted off for drinking water.

Thames Water’s £250m scheme would involve abstracting 75m litres of water a day from the River Thames at Teddington, south-west London, in times of drought, and replacing it with treated sewage from the nearby Mogden sewage treatment works via a new tunnel.

The company is promoting its water recycling project as one solution to finding more water sources in the coming decades, and the use of indirect water recycling is also being promoted by other water companies in their draft plans for the next decades.

But campaigners have raised a number of potential environmental concerns such as damage to river systems from the increased water temperatures caused by pumping treated sewage into the river during low flow, a change in the salinity of the river, and the impact on fish and biodiversity. Critics say fixing Thames Water’s leaks of 630m litres a day would provide much more water than the recycling project.

Ian McNuff, a founding member of Save Ham Lands and River, said there were multiple flaws in the scheme. He believed it was not a long-term strategic solution to providing future water resources. “Thames Water keeps trying to tell us this won’t make the river any worse … But we want to make the river better, healthier and more resilient for the future. This will only cause more pollution.”

And he raised another concern, over the impact on river quality from so-called forever chemicals, per- and polyfluoroalkyl substances (PFAS), potentially contained in the treated effluent. “Thames will not be screening for these, and there are increasing concerns worldwide about the impact of these chemicals on river systems.”

Raw and treated sewage, discharged by water companies into rivers, and agricultural runoff are the key reasons that rivers in England are in a dire state. No river has passed key chemical and biological tests for water quality as a result of pollution. Data published last week revealed Thames Water had pumped more than 72bn litres of sewage into the River Thames since 2020.

Water recycling is already used in countries such as Australia and Singapore. But in Singapore it is direct potable recycling that is being pursued, with treated effluent not discharged into a river or lake system, but instead highly treated and taken direct to the tap.

As Thames Water puts its plans out to a second consultation, tens of thousands of people have signed a petition against the project, which is also opposed by local MPs and the council. The company has been invited by the council to a town hall meeting on 27 November but has not yet accepted the invitation.

Nevil Muncaster, strategic partnerships director at Thames Water, said: “Our proposals for the Teddington DRA project are at a very early stage and we want to work with our stakeholders and with local communities to shape them. Water is an essential resource to keep the city functioning and in London we supply around 2bn litres every day; that’s equivalent to 25m baths. We need to plan ahead, to meet a growing demand and prepare for extreme heat, as seen in 2022 when temperatures reached record highs in the UK.”

Trust in Thames Water, which is at the centre of a criminal investigation by the Environment Agency and an inquiry by the regulator Ofwat over illegal raw sewage discharges, is a key issue among local campaigners.

John Bryden, of the campaign organisation Thames 21, argued that the Thames Water proposal had the potential to increase pollution in the river, and that water companies in the UK should instead be looking at direct water recycling, from treatment works to the tap, as a better water resource for the future.

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“Forever chemicals in the treated effluent will definitely be an issue as a result of this scheme and increase the pollution load on the river,” he said.

The Environment Agency has said Thames Water must invest in new research and development to identify ways to substantially reduce its leakage, before pursuing the recycling project, where there are reservations on environmental and long-term viability.

Campaigners are also trying to prevent the destruction of a protected nature reserve which is threatened by the building works for the new tunnel. The 72-acre site, Ham Lands, is a designated site of importance for nature conservation (SINC) – an area of substantive nature conservation value.

Water recycling is likely to provide just a small portion – about 7% – of the new water needed by 2050, which is equivalent to the demand of a 9 million strong population, experts say. Critics say reducing public demand for water is required, with a major public education campaign.

Munira Wilson, the Liberal Democrat MP for Twickenham, said fixing just over a tenth of the leaks would deliver the water being proposed in the “controversial” scheme. “Trust in our water companies is at an all-time low. Local residents and river users will be forgiven for asking whether what they are actually proposing in terms of putting treated sewage into our river is feasible, is good for us, not to mention the risk of turning conservation areas into construction sites.”

The Guardian