Complaints about smells from wastewater treatment works fell by 19 per cent to 405, the fifth consecutive year in which there has been a reduction.

Key factors behind this success are substantial capital investment and implementation of our Odour Management Plan.

Six out of eight approved odour control schemes have been completed. A sustainable, green technology solution has been used at Ham Hill in Kent and Peel Common in Hampshire, where natural materials, such as bark, wood chips, seaweed and seashells, are used as filtering media.

Bugs live on these materials inside enclosed tanks and break down gases, such as hydrogen sulphide, that cause smells. The treated gas is eventually vented back to the atmosphere.