Storm overflows causing severe discharges of sewage are ‘unacceptable’ and must be addressed, argued the boss of Thames Water.
Sarah Bentley, chief executive of the UK’s largest water supplier, confirmed the company’s “corporate change in position” at the House of Lords today.
She warned that Thames Water was facing two challenges when it came to managing sewage overspills in London.
Firstly, the capital’s combined sewerage and surface system was first constructed by Sir Joseph Bazalgette during ‘The Great Stink’ in 1858, serving a city of two million people rather than the nine million across Greater London today – which was “stretching it’s availability.”
Bentley also noted that London was shedding permeable surface area every year for rain water – around 2.5 Hyde Parks per year.
She said: “Over the last 10-20 years, over 50 per cent of London has been concreted. So, the amount of rainfall is really the issue. Which is getting in and then being contaminated with sewage.”
The water boss confirmed that Thames Tideway Tunnel will help mitigate the issue, with the project aiming to cut sewer discharges by 95 per cent on completion.
Thames Water targets improvements
Bentley was bullish that Thames Water can normally cope with treating sewage and managing rainfall – and that it was deluges and high groundwaters that were “overwhelming” their works and causing discharges.
The Government has established targets for reducing sewer overflows as part of a reduction plan unveiled this summer by the Department for Environment, Food and Rural Affairs.
It is demanding water companies to improve 75 per cent of overflows discharging into high priority nature sites and all overflows into designated bathing water.
By 2050, this will apply to all remaining storm overflows covered by Government targets, regardless of location.
Bentley was speaking to the House of Lord’s Industry and Regulators Committee, which is assessing the role of Ofwat in the water industry.
Thames Water serves almost a quarter of the UK population with water and wastewater services.
It launched an overhaul of its business in March, following reports last October that Thames Water illegally discharged the equivalent of two years’ worth of untreated sewage into rivers.
Currently, it is under intense regulatory scrutiny from Ofwat, after the industry watchdog raised “serious concerns” over its treatment of sewage.
The watchdog has since slapped six water companies with enforcement cases.
It also teamed up with the Environmental Agency to announce investigations into all water and wastewater companies last November.