‘Inadequate Infrastructure’ Leading To Increased Sewage Overspills

Why is water efficiency important - H2O Building Services


Sewage overspills have been hitting the headlines with increasing frequency over the last few years, with raw waste discharged into rivers, lakes and streams across the UK and Ireland on a daily basis.


This is permissible during periods of heavy rainfall, when the capacity of the combined sewage system (which was built by the Victorians) can be exceeded.


This means that sewage works can potentially be inundated with wastewater and back up into homes, roads and open spaces… so to prevent this, water suppliers are allowed to use combined sewer overflows to reduce the risks.


However, as climate change brings with it more frequent and more intense extreme weather events, the sewer system is likely to be overwhelmed more often… particularly when you take into account the country’s ageing infrastructure.


New research from Imperial College London has found that the recent increase in sewage overspill events is down to the fact that this infrastructure is currently unable to keep up with demand.


As such, it will be essential to find a range of different solutions to resolve this pollution problem, with blockage prevention and the separation of rain and foul water unlikely to be sufficient by themselves.


There are currently 14,346 CSOs to be found in England, all of which have been assessed for their environmental risk. However, questions have since been raised about the role they have to play in the nation’s wastewater systems, because of their increasing use, even during dry conditions.


Raw sewage overspill that lands directly into rivers and the sea can cause water pollution, especially when the CSOs are used when there’s no rainfall, which dilutes the sewage. The end result is environmental deterioration and human health hazards, which can have knock-on effects for leisure and tourism, as well as seafood consumption.


This latest data analysis indicates that most of the discharge increase is down to capacity issues in wastewater treatment works, which are struggling in the face of rising population numbers and more intensive industrial activities.


Professor Nick Voulvoulis lead researcher said: “Our findings reveal the chronic under-capacity of the English wastewater systems as a fundamental cause behind the increased frequency and duration of CSO spills.

“We hope this work can help the water industry demonstrate the need for capital investment in infrastructure. It is often taken for granted but investing in infrastructure is critical to our future prosperity.”


Between 2000 and 2008, just over one per cent of the sewers across England and Wales were replaced or upgraded. If this rate of replacement continues, given that most of the UK’s infrastructure was only intended to last between 60 and 80 years, it would take 800 years for all sewers to be replaced.


Do you want to find out why water efficiency is important? Get in touch with the H2o Building Services team today to see how we can help.