{"id":751206,"date":"2026-08-27T08:26:10","date_gmt":"2026-08-27T08:26:10","guid":{"rendered":"https:\/\/www.newsbeep.com\/uk\/751206\/"},"modified":"2026-08-27T08:26:10","modified_gmt":"2026-08-27T08:26:10","slug":"forever-chemicals-surge-during-pilot-of-thames-water-plan-to-combat-drought-water","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/uk\/751206\/","title":{"rendered":"\u2018Forever chemicals\u2019 surge during pilot of Thames Water plan to combat drought | Water"},"content":{"rendered":"

Levels of a toxic \u201cforever chemical\u201d rose to 13 times the legal limit during Thames Water<\/a> pilots for a controversial multimillion pound water recycling scheme that will pump millions of litres of treated sewage into the River Thames during drought.<\/p>\n

The data from the pilots is in stark contrast to public comments from Thames Water<\/a> that their water recycling project in south-west London will not harm the riverine environment.<\/p>\n

In technical notes in the company\u2019s files for the project, seen by the Guardian, the results from two pilots reveal the recycling system rapidly and significantly increased levels of a particularly toxic type of Pfas chemical perfluorooctane sulfonate (Pfos), a suspected carcinogen \u2013 breaching the legal limits by as much as 13 times.<\/p>\n

As standard wastewater treatment plants are not designed to filter or destroy them, treated and untreated sewage contains Pfas chemicals (short for per- and polyfluoroalkyl substances). They are known as \u201cforever chemicals\u201d because they do not break down in the environment, and the detrimental impact on rivers has been found<\/a> to be widespread. New figures<\/a> show every English water body is polluted with toxic chemicals. They are also considered a threat<\/a> to human health.<\/p>\n

Thames Water\u2019s recycling system<\/a> is intended to provide more water to cope with shortages resulting from both a rising population, and predicted droughts caused by climate breakdown, over the coming decades.<\/p>\n

It involves abstracting up to 75m litres<\/a> of water a day from the Thames at Teddington, south-west London, when the river is in low flow at times of drought, and replacing it with the same amount of treated sewage from the Mogden treatment plant via a new tunnel into the river. The 75m litres a day is a fraction of the 571m litres of water the company leaks each day.<\/p>\n

The results of the company\u2019s tests, however, reveal the scale of the treated sewage input would make it very difficult for the water to meet current standards for forever chemicals and pesticides.<\/p>\n

Thames Water, which is seeking a development consent order for the scheme, has insisted publicly that the water recycling system \u2013 which will cost at least \u00a3350m \u2013 would not harm the river, its habitats or be a threat to the public.<\/p>\n

But the technical note on the pilots shows levels of Pfos rose to 6.3 nanograms per litre in test one and 8.7 nanograms per litre in test two of the recycling technology. The UK legal limit for surface waters is 0.65 nanograms per litre.<\/p>\n

The documents show there was a \u201crapid breakthrough of Pfos\u201d above the legal threshold in less than one month of operation. The company said keeping within legal limits would be \u201coperationally challenging\u201d, requiring carbon filters to be frequently regenerated, reactivated and replaced, and would require \u201csignificant additional operational expense\u201d.<\/p>\n

In addition to the forever chemical, the pilots also showed the treated water contained very high levels of iron, which the document states would have a \u201csignificant detrimental impact\u201d on the river.<\/p>\n

Swimmers at Teddington Lock on the River Thames, 9 July 2026. Photograph: Dan Kitwood\/Getty Images<\/p>\n

Ian McNuff, of the campaign group Solar<\/a>, which opposes the project because of what they say will be irreversible environmental damage to the river, said: \u201cThames Water described the results for the pilot as \u2018operationally\u2019 challenging.<\/p>\n

\u201cIn essence, they can\u2019t make it work properly. Test failures were rapid, and the idea that they can switch this on and off as a completely reliable asset during drought is unrealistic against current standards, let alone the higher ones expected around Pfas and pesticides.\u201d<\/p>\n

Costs for the water recycling scheme are already rising for Thames, which is struggling under debts<\/a> of \u00a320bn and teetering on the brink of a government-handled administration.<\/p>\n

The original cost of \u00a3350m is now expected to rise to more than \u00a3500m, as Thames Water has discovered it needs to install more mechanical pumps within a nature reserve near Teddington to pump the water, according to sources close to the project.<\/p>\n

The Environment Agency<\/a> has been given the results of the two pilots carried out by Thames Water. The agency rejected an earlier scheme in 2019 because of the unacceptable impact on the environment of releasing millions of litres of treated effluent into the river.<\/p>\n

The project is opposed by the local council and local MPs, including the Liberal Democrat MP Munira Wilson. But as a strategic infrastructure project, it can be pushed through without local consent.<\/p>\n

An Environment Agency spokesperson said: \u201cWe have strict legal requirements in place to protect our rivers, groundwater and drinking water catchments from toxic chemicals and the Teddington site will continue to undergo rigorous environmental assessments to ensure these conditions are met before any development work can begin.<\/p>\n

\u201cEnvironmental protection and sustainable development must go hand-in-hand and water recycling projects, combined with new reservoirs, will be critical to securing future water supplies effectivity.\u201d<\/p>\n

A Thames Water spokesperson said: \u201cThe Teddington Direct River Abstraction (TDRA) project will not be allowed to operate without securing an environmental permit from the Environment Agency.<\/p>\n

\u201cThe pilot plant study was set up to test a range of technologies to help inform and refine the final design of the tertiary treatment plant. The data from the pilot plant study is not indicative of what would be released back into the river when the project is operational.\u201d<\/p>\n

The spokesperson added: \u201cWe want to see Pfas banned and the development of a national plan to remove it from the environment, which should be paid for by manufacturers as opposed to water bill payers.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":"Levels of a toxic \u201cforever chemical\u201d rose to 13 times the legal limit during Thames Water pilots for…\n","protected":false},"author":2,"featured_media":751207,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[59,57,58,50,56,54,55],"class_list":["post-751206","post","type-post","status-publish","format-standard","has-post-thumbnail","category-united-kingdom","tag-gb","tag-great-britain","tag-greatbritain","tag-news","tag-uk","tag-united-kingdom","tag-unitedkingdom"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/posts\/751206","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/comments?post=751206"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/posts\/751206\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/media\/751207"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/media?parent=751206"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/categories?post=751206"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/tags?post=751206"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}