H2O GLOBAL NEWS M A G A Z I N E
July 2022 Issue 2
Using assessments and maintenance to tackle your CSO targets
The use of Combined Sewer Overflows (CSOs) continues to place water companies under intense scrutiny. In response to bleak Environment Agency figures and scathing media reports, policymakers and the public have called for tighter management and tougher enforcement.
T
he move to better has begun. In March 2022, the Department for Environment, Food and Rural Affairs (DEFRA) published a consultation on its Storm Overflows Discharge Reduction Plan. The document outlined Government’s plan to address sewage overflows, detailing actions for operators, regulators, and consumers. At the same time, water companies are exploring innovative solutions to boost network capacity and cut reliance on CSOs.
Matthew Humphreys, Utilities Sector Manager, Adler and Allan, discusses the role of ongoing assessment and maintenance in the race to reduce CSO spill incidents by 320,000 before 2050 – and the importance of changing the national narrative.
Reframing the CSO situation In recent years, a growing population, ageing infrastructure, and changing climate have placed extreme pressure on the UK’s water system. Centuries-old pipework has buckled under the strain, and CSO discharges – the system’s in-built ‘release valve’ – have sharply increased. Environment Agency (EA) statistics show that the ten UK water
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and wastewater companies expelled raw sewage into rivers more than 400,000 times during 2020. The EA’s Event Duration Monitoring (EDM) data – which tracks when spills happen and how long they last – shows the releases discharged for 3.1 million hours. Water companies are taking steps including investing £7.1 billion between 2020 and 2025 to protect the environment. Of this, £3.1 billion is earmarked specifically for storm overflow improvements. Similarly, all storm overflows will be monitored by the end of 2023 (up from 80% currently) and operators must report the frequency and duration of spills to the EA on an annual basis. To successfully address the CSO issue, however, we need to tackle root cause – which is not as cut and dry as the media makes out. CSOs are an essential part of the sewer network, not a defect of it. They were originally created to prevent drains being overwhelmed in heavy rainfall and backing up into homes, businesses, and roads. The rise in CSO spills is often attributed to overpopulation and overdevelopment. In other words, too many people and too many houses, generating more wastewater than the system can deal with.
