Saturday, December 24th, 2011
Drain blockages in London are an all too common occurrence, as the city’s Victorian sewer system struggles with the pressure put on it by modern life.
When the Victorians built the London sewer network, they were not to envisage the population boom the city has seen over recent decades. And although the system has done well coping so far, there is still far too much sewage dumped into the River Thames at times of heavy rainfall.
Currently only around 2mm of rainfall can trigger a discharge into the River Thames from one of the 57 sewer overflows on the river. When the Thames Tunnel is built it will take the discharge from the 34 most polluting sewer overflows and transfer it to Beckton Sewage Treatment Works where it will be processed.
Thames Water say that on average a discharge is released around 50 times every year and a total of 39 million tonnes of sewage is released into the river. If the proposed tunnel build does not go ahead the forecast for annual sewage release is expected to increase to around 70 million tonnes, which could have a huge impact on the river and its wildlife.