Engineers urge UK action on sewage to guard against sickness outbreaks

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Maintenance, real-time monitoring, and UV disinfection among the required interventions

IMMEDIATE action to bolster maintenance of the sewage system and sensors to allow real-time monitoring of water quality are among engineering experts’ recommendations to reduce the risk of harmful organisms polluting UK’s waterways and making people sick.

Engineers assembled by the Royal Academy of Engineering (RAEng) ranked the costs and effectiveness of a range of wastewater measures for their report, Testing the waters, which was released on 21 May at a time of increased scrutiny for the UK’s water industry.

David Butler, chair of RAEng’s National Engineering Policy Centre working group on wastewater, said: “Growing urbanisation and forecasts for more frequent and intense rainfall events due to climate change will mean increasing pressure is put on our ageing wastewater system. Policymakers and industry should carefully consider the actions we have outlined here and their implications in future wastewater infrastructure projects.”

Sewage spills and public health

The recommendations come amid heightened pressure on the water industry to stop spilling sewage into waterways. Last year, industry spilled sewage into the environment through storm overflow pipes at a rate of 1,271 times a day.

This is one of two routes that introduce so-called faecal organisms from human sewage into the environment. The other is the treated effluent that is continuously discharged from wastewater treatment plants. These plants reduce the concentrations of harmful bacteria and viruses but do not eliminate them.

With the water system and those who operate it justifiably under fire for the environmental pollution caused by spills, the report’s contributors underscore that sewers have saved millions of lives by preventing faeces from contaminating drinking water, massively reducing outbreaks of cholera and typhoid.

With water companies set to invest £96bn (US$122bn) between 2025 and 2030 to meet the water regulator’s demands to reduce environmental pollution and boost water supplies, the report’s contributors said now would be a good time to bolster the public health benefits too.

Sir Chris Whitty, chief medical officer for England, said: “For several decades now, the principle thing that the system has been designed to do is reduce environmental impact. Our view is actually we should rebalance this so that the public health elements are part of the decision-making as to what investment goes where.”

He acknowledged that the evidence base is “quite thin” because it is difficult to trace an individual person’s illness to a specific leak. Despite this, he said engineering interventions should be targeted to minimise risk where people are most likely to be exposed.

Sir Chris said: “We’ve just been through one major pandemic. I’m not suggesting we’re going to go through another one led by the sewage system, to be clear. But I think it reminds us that thinking about all of the routes of transmission and minimising the risks down those routes is very sensible.”