Sewage treatment

Wessex Water"s sewage treatment works treat millions of litres of sewage every day. The sewage goes through the following processes: debris, rags and large objects, are removed using screens, sewage flows into tanks where the solids sink to the bottom and are removed as sludge, the sewage is treated biologically - the liquid passes through media with bacteria growing on them, such as filters of stone or plastic. The bacteria feeds off the waste, helping to clean the water. Another form of biological treatment used by Wessex Water is known as the activated sludge process. Bacteria are mixed with the waste in large tanks using equipment which either blows or beats air into the mixture. The cleaned effluent leaves the treatment works and flows into local rivers or the sea. The treated effluent enters settlement tanks where any remaining solids settle leaving water which is ready to be returned to the environment.