Thermal Hydrolysis to replace AD sludge treatment in London

Cambi has been awarded a contract to provide thermal hydrolysis process (THP) technology for utility Thames Water’s Beckton and Crossness Sewage Treatment Works advanced digestion projects in London.

Two separate B12 Cambi plants will be supplied under a subcontract from Tamesis – a joint venture between Laing O’Rourke and Imtech Process – who is the contractor for the Crossness facility upgrade. Work is slated for completion in 2014.

Located on the north bank of the river Thames just east of Docklands, Beckton sewage treatment works was first connected to the London Sewer network in 1850. Today, it serves a population of 3.5 million people and is one of the largest treatment works in the UK. Situated on the south bank of the Thames nearly opposite, CrossnessSewage Treatment Works serves two million people.

The original process at both plants was anaerobic digestion followed by the disposal of the treated digested sludge in the North Sea. In 1998 Thames Water commissioned fluidized bed SPGs (Sludge Powered Generators) to provide an opportunity to generate renewable energy from London’s waste and to comply with EU legislation prohibiting all disposal to sea, both treated and untreated sludge.

Due to capacity pressure, the replacement chosen method is to pre-treat the secondary sludge with Cambi thermal hydrolysis and anaerobically digest it before making an agricultural grade fertilizer. The final pasteurized biosolids will be dewatered and used in agriculture close to London. Generated biogas would have the potential to generate 4MW of electricity per plant, according to Cambi.

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