This week’s heavy rainfall has once again, for the third time this month, led to United Utilities pumping sewage into the sea off St. Anne’s North – consequently, the Department for Environment, Food and Rural Affairs has issued a warning to beachgoers to stay away from the waves, and not to go into the water. Sewage was also previously pumped into the sea on 4th May and 6th May.
A United Utilities Spokesperson said, ‘The sewer network is built in such a way that when there is heavy rain, there is a risk of flooding at our waste water treatment works. If there’s a risk of those being overwhelmed, we have permission to discharge storm water to relieve that in order to avoid flooding.’
United Utilities have a significantly higher proportion of combined sewers than any other water company. Over 54% of their public sewers combine foul and surface water (compared to an industry average of 33%). Combined sewers respond quicker to a storm with the capacity filling up more quickly when compared to more separate systems. United Utilities have 25% more sewer overflows than the industry average. The company say that storm overflows are an important part of the sewerage network and include combined sewer overflows (CSOs) and storm tank discharges. These act as a pressure relief valve when there is too much rainfall, allowing rain water, mixed with sewage, to rise inside the sewer and eventually enter a separate pipe which flows into a river or the sea. Sewers operate this way to help prevent the flooding of streets, homes and businesses. The Company says that when they use storm overflows, these can sometimes affect river and bathing water quality, adding ‘albeit temporarily’.