Thames Tideway Earl Pumping Station

Located in Southeast London, the Earl Pumping Station sits within an operational sewage treatment works, surrounded by industrial sites dating back to the 1800s. This historical usage left a legacy of hydrocarbon-contaminated groundwater, which would require treatment before discharge to a receptor.

As part of the Thames Tideway Tunnel project, a shaft was constructed to connect the new “super sewer” to the existing stormwater and sanitary sewer network. The shaft, built using a secant piled wall, was constructed and excavated by CVB Joint Venture (Costain, Vinci, Bachy), who engaged WJ to manage the groundwater drainage and treatment.

Initially, the task was straightforward due to low leakage rates, with flows under 5 litres per second being pumped and treated. However, during excavation into the river terrace gravels at approximately 10 metres below street level, and following the breakthrough out from the shaft, wall, flow rates increased to 10 litres per second.

WJ deployed a treatment system with a total capacity of 75,000 litres, designed to meet stringent discharge consent requirements at flows of up to 15l/sec. The system was continuously monitored and operated reliably for 2.5 years, ensuring full compliance throughout.