Septic tank
A septic tank is an underground chamber made of concrete, fiberglass or plastic through which domestic wastewater (sewage) flows for basic treatment. Settling and anaerobic processes reduce solids and organics, but the treatment efficiency is only moderate (referred to as "primary treatment"). Septic tank systems are a type of simple onsite sewage facility (OSSF). They can be used in areas that are not connected to a sewerage system, such as rural areas. The treated liquid effluent is commonly disposed in a septic drain field which provides further treatment. However, groundwater pollution may occur and can be a problem.
Abbey Mills Pumping Station
Lee Tunnel is a sewage tunnel that travels from Abbey Mills to Beckton Sewage Works and is designed to handle the 16 million tons of overflow sewage that was previously discharged into the River Lea each year. The tunnel boring machine's name, 'Busy Lizzie', was chosen via a competition open to local school children. Thames Water began construction in 2012 and on 28 January 2016, in a visit to the operations, London mayor Boris Johnson opened the tunnel for service.