Almost 10,000 people have signed a petition against proposals by Thames Water to tackle drought by drawing off up to 100m litres of water a day from the Thames and replacing it with treated effluent from one of Europe’s biggest sewage treatment works.
The company, which leaks 630m litres a day from its pipes, is attempting to get a new scheme approved involving tens of millions of litres of treated effluent being pumped into the Thames from Mogden sewage works in west London to tackle future water shortages.
Concerns over the impact of chemical pollution from the treated sewage, including harm from “forever chemicals”, has angered river users.
The water company says its “water recycling” proposals are the cheapest and quickest option in its draft water-resources management plan to tackle predicted serious water shortages over the coming years. The building of a new reservoir is not likely to happen until at least 2040 and Thames Water’s plans to reduce leaks by 50% will not be achieved until at least 2050.
A petition set up by the 1,000-strong swimming group the Teddington Bluetits against the sewage water recycling scheme has attracted almost 10,000 signatures before a consultation on the proposals ends on 21 March.
Magnus Grimond, from the swimming group, said the proposals were a significant threat to the fragile ecosystems of the river. “There is scientific evidence that treated sewage can have ill-effects on water-based creatures, both through changes in the chemical makeup of the water and its temperature,” he said.
“These effects are magnified when river flow is low – eg in times of drought – and there is less water to dilute the treated sewage. It is just at these times that Thames Water will need to increase the flow from the Mogden sewage works.”
Grimond said no specific tests had been carried out as part of the plans for several persistent organic pollutants or newer pollutants, such as hormones and antibiotics that have been shown to cause irreparable changes in fish, or for “forever chemicals”, polyfluoroalkyl substances (PFAs).
Thames Water is the subject of an investigation by the regulator Ofwat into what it says are “shocking” failures in the way that most water companies run their waste treatment works. It was given the a two-star rating by the Environment Agency for its environmental performance last year and a red rating for serious pollution incidents.
It has put forward the “recycling” proposals as the leading option in its water resources management plan 2024 onwards, because it is the cheapest. “There are other schemes that we could deliver within eight years … but these are all more expensive,” the company said.
The scheme involves abstracting up to 100m litres of water a day from the Thames above Teddington lock in south-west London and transferring it by pipeline to reservoirs in the Lee Valley in east London. The abstracted river water would be replaced by treated effluent from Mogden, one of the biggest sewage plants in the UK. Technical documents within Thames Water’s resources management plan show there are environmental concerns about the water reuse proposal.
Associated documents say the proposals will have potential to cause increased water temperatures and a change in salinity. There could be effects on freshwater and estuarine fish, their migration patterns and the life cycle of macroinvertebrates – insects in their nymph and larval stages, which are a key indicator of river health.
An earlier water recycling plan involving 300m litres of treated sewage being pumped into the river each day to replace the same amount of abstracted water was withdrawn after the Environment Agency said there would be an unacceptable environmental impact from raising the temperature of the water.
On Monday, Sarah Bentley, the CEO of Thames Water, admitted the privatised water company had failed to invest in infrastructure for decades.
Munira Wilson, the Liberal Democrat MP for Twickenham, said: “These plans are necessary because Thames Water has failed to fix leaks losing them a quarter of their precious daily supply, all whilst handing out millions in bonuses to their chief executives. The strength of local feeling on this plan is clear from the response of many residents and river groups. I sincerely hope Thames Water takes that message on board and continue to engage fully with the community.”
Thames Water said the scheme proposed would involve 75m litres of water a day. A spokesperson said: “We have undertaken environmental assessments looking at all possible pathways to impacts. The assessments complete to date show that a scheme up to 100m litres a day would meet Environment Agency guidance.
“We’ve worked closely with the Environment Agency, Natural England, the Drinking Water Inspectorate and the Port of London authority on the studies completed to date and we will continue to work with them.”
A consultation on the proposal runs until 21 March.
