Out To Dry

Each day in the UK, the average person produces 150 litres of waste water from household activities. 13% of this is ‘grey water’ from laundry; a mixture of detergents, fibres, water and dirt. Researchers from Plymouth University concluded that 'laundering 6 kg of synthetic materials could release between 137,951–728,789 fibres per wash' depending on the wash cycle, detergent and temperature of the water.

The grey water makes its way into the sewer system and eventually to your local water treatment plant. Here it goes through a series of steps to remove contaminants so it can be returned into the nearest river or the sea. However, due to the design of the sewerage system, sometimes waste water doesn't make it to the treatment plant at all.

Birmingham's sewer system was built in the Victorian era; from 1851 onwards, all new houses built in the city had to be connected to a sewer. The main London sewerage network was built in the late 1800s. Both networks were built for a much smaller population than they support now. Valves are built-in to the system, to release excess water from rainfall or heavy use of the network; these valves make sure that excess water doesn’t flood back up into our homes, but instead send it into rivers and canals as untreated sewage containing microplastics, faeces, and bigger pieces of plastic waste such as wet wipes and cotton earbuds. The Thames Tideway tunnel scheme is addressing this problem in London, but is not scheduled to be completed until 2025 and will not intercept all CSOs, although once completed it will result in a subtantial reduction in CSO events and their duration.

Water companies are meant to limit the amount of times the sewage network releases this untreated water into rivers. Each water company has a permit stating that sites can only discharge sewage into rivers if a certain rainfall level is reached or if the site is dealing with far more sewage than usual. A recent Panorama programme shared the work of clean river campaigner Peter Hammond, who mapped discharges from sites against levels allowed by the permit and found that sites frequently exceed their permits, some for months at a time.

The Environment Agency reported that untreated sewage was discharged 403,171 times, for over 3 million hours, across England in 2020.