Reading Sewage Treatment Works

Officially opened in 2005, Reading Sewage Treatment Works is one of the UK's most technically advanced sewage works.

The £80 million plant treats wastewater for 284,000 people. Its centrepiece is four, 20-metre-high, egg-shaped digesters.

Reading is one of 21 of our sewage treatment works that can generate renewable energy. Here we use a process called Combined Heat and Power, in which we burn methane, a by-product of the sewage treatment process, to drive an engine, creating energy. The electricity generated from this process is used to generate 48 per cent of the electricity needed at the site, reducing the amount of power imported from the Grid. This is equivalent to the electricity consumed by 1,300 homes or 3,277 tonnes CO2 e (carbon dioxide equivalent).

In addition, the exhaust heat from the electricity generation plant is also captured and in turn used to pasteurise the sewage sludge so that it can be disposed to agricultural land as a useful fertiliser.

To reduce our carbon emissions further we have implemented a number of energy-saving measures at Reading:

• There are many buildings on site, so we have installed switches which turn off the lights after 20 minutes - this saves 80 per cent of lighting costs here.
• Solar-powered lighting bollards and solar-and-wind-powered lampposts have been installed which switch on and off automatically. This has enabled us to switch off all other outside lighting.
• The gatehouse at the entrance of the works generates all its power through a wind turbine.
• Meters have been installed to monitor how much power is used at individual parts of the treatment process. This will enable us to target our future investment at the most energy intensive areas.

Overall, we believe these additional measures at Reading have reduced our carbon emissions by 193 tonnes per year. This is the equivalent of taking 77 cars off the road, and will save us £25,000 per year in energy costs.