LETTERS – No quick fix for sewage problems

Your contributor (Time to sort sewage problems) raises an important issue.
The water companies are correct when they refer to the increases in both rainfall events and intensities which are causing ever more wastewater overflows.
Increases in global temperatures are driving these events. Having said this, water companies have been slow to react bearing in mind that this has been on the horizon for some time.
Unfortunately, there is no quick fix solution and wastewater flooding and overflows to rivers and the sea will continue for some time and this is something people will have to accept.
Some improvements such as new relief sewers, increased capacity at wastewater treatment works and maintenance will provide some improvement in the shorter term.
The longer term solution is to intercept excess flows and divert them to underground storage tanks. Once the storm has abated, flows would then be pumped back into the sewerage system for onward treatment. This is not as straight forward as it seems as suitable sites will need to be identified requiring sophisticated modelling of the sewerage system, possible compulsory land purchase, obtaining regulatory approval and requiring robust engineering solutions.

Michael Quenault C.Eng M.I.C.E
via email