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Wastewater plant to supply gas using ‘black gold’

United Utilities’ award-winning wastewater treatment works in Davyhulme, Manchester, is set to feed biogas produced from sewage sludge to the grid, turning waste into a renewable energy source.

United Utilities’ award-winning wastewater treatment works in Davyhulme, Manchester, is set to feed biogas produced from sewage sludge to the grid, turning waste into a renewable energy source. 

The anaerobic digestion centre currently generates electricity from the biomethane it produces and has previously been branded as one of the most innovative green energy schemes in the UK. 

However, a new upgrade will clean the gas enough for it to be fed into the grid for the first time - allowing homes and businesses to use it for heating.

‘Black gold’ 

Tom Lissett, sludge business manager at United Utilities, said: “We’re always looking at ways to maximise the amount of value we can get from sewage sludge.

“It might have been considered a waste stream at one time, but now we call sludge ‘black gold’. Already we use our biogas in engines to generate renewable heat and electricity from Davyhulme - enough to power the entire works. 

“As we increase the efficiency of the sewage and sludge treatment process we are able to generate more biogas and as a result we’ll be able to put that into the gas grid for the very first time.”

Increased efficiency

A gas pipe to connect the plant to the existing gas network has already been built, while a new pre-treatment cleaning plant will make sure the biogas is pure enough to be injected into the grid. 

The pre-treatment process also increases the amount of biogas produced by the sludge, meaning that more renewable electricity will be generated on-site as well as more gas fed into the grid. 

Cutting costs

Lisset added: “Everyone will benefit from our more flexible approach to utilising biogas for electricity generation and supplying ‘green’ gas to the grid.

“This maximises the benefits we can obtain from the biogas we produce which will help us protect our customers from higher bills in the future.”

The UK is believed to be the fastest growing market in the world for biomethane-to-grid connections, with a total of 50 plants now operational, 23 of which were completed in 2015.