Water company says new techniques can help it extract 90% of calorific value from sewage sludge

Thames Water is planning to greatly increase the amount of energy it can extract from sewage sludge.

The water company can currently only extract half of the calorific value – the energy contained in raw sewage – from the sludge it treats by using anaerobic digestion (AD) to turn it into gas.

However, external affairs and sustainability director Richard Aylard told the London Infrastructure Summit yesterday that the company was developing new AD methods that could nearly double the amount of energy it can use.

“That will get us to 90% and also massively reduce the amount of residue that has to go out to farms,” Aylard told delegates.

Aylard also told the event, which was organised by the London First business lobbying group, that Thames Water was drawing up waste and water strategies for five of London’s fastest growing areas.

He said that the Greater London Authority’s (GLA) ‘opportunity areas’, which have been earmarked as areas of housing growth, provided the best potential for improving London’s waste and water network.

He said: “Retrofitting is pretty difficult in the waste and water area, if not impossible. We have mapped waste and water networks against those areas and we have identified five that need integrated water management strategies right at the outset.

“Once strategies are written we will have to be very disciplined in delivery; people won’t be able to take short cuts that they have in the past which have led to deterioration in the network in the past.”

At the same session, Shirley Rodriguez, London’s deputy mayor for environment and energy, said that the GLA was exploring how to source replacement finance, post-Brexit, for EU funding that has played a crucial role in bankrolling environmental projects such as energy efficiency measures and heat networks.

She said: “The GLA has been successful at getting resources into London from the EU. We are now looking at how we will replace that through mobilising more of the private finance that will need to go into this sector.”

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