KSB will supply four 52 ton wastewater pumps for the construction of the Lee Tunnel in London. Each of these pumps will feature an impeller measuring 2.2m in diameter. A total of six pump sets, including two smaller drainage pumps, will be installed in a shaft structure 85m below the Beckton Sewage Treatment Works in London, Britain’s largest wastewater and sewage treatment plant, and used to transport combined storm water and sewage.
These wear-resistant, white cast-iron pumps will each be driven by a 6600 volt motor with a drive rating of 3.4MW, controlled by a frequency inverter. To keep these motors cool, the pump manufacturer will deploy heat exchangers specially engineered for this underground application. Compared with equivalent air-cooled systems, these heat exchangers will sharply reduce the amount of energy required to dissipate the thermal load.
The shaft structure will be located at the end of the approximately 7km Lee Tunnel. The goal is to prevent an untreated mix of storm water and sewage from entering the Thames during periods of heavy rainfall. With a diameter of 7m, the Lee Tunnel will be able to capture and temporarily store some 382,000CUM of storm water.
By the final stage of construction, the tunnel will have a total length of 39km and around 40 shafts. It will follow the course of the Thames at a depth of 25 to 80m, making it the deepest tunnel in London and one of the deepest wastewater tunnels in Europe.
At a cost of GBP 675 million, this is the most expensive water project ever undertaken in the United Kingdom. It is scheduled for completion in 2015. Once in operation, the pumps will be maintained and serviced by the specialists from British-based KSB Limited.