Food waste from London can now be transformed into biogas and fertiliser

Willen Biogas is now helping London manage the city’s waste in a greener manner. Xergi has supplied the biogas plant and will be responsible for the operation over the next two years.

Willen Biogas Limited has been very satisfied with the new biogas plant supplied by Xergi which it took over during May this year. The plant processes food waste from London into CO2-neutral biogas and green fertiliser.

The project started in late August 2014 with a very comprehensive time schedule put in place with milestones to be reached at specified dates to ensure delivery of the complete project on time.

“We have been very impressed with Xergi and the commitment its project manager gave the Willen project. We felt that he took the project on personally and made sure nothing would compromise the situation of achieving the ultimate goal. Obviously with any project of this size, occurrences happen and unforeseen problems arise. However, the project team had a very practical way of attacking potential problems and was still able to bring the project timelines back to the desired timelines,” says Adrian Williams, one of the investors behind the plant.

“In summary the project ran very well, achieved the timelines and we managed to start producing electricity slightly earlier than anticipated and also remained on budget throughout the build program.  We would definitely use Xergi and their project team on our next anaerobic digestion project,” states Adrian Williams.

Together with his family members Howard and Brian Williams, he owns Cattlegate Farm on the outskirts of London where the biogas plant has been built. The other investors are the Williams’ business partner, Mark Lennon and the Foresight Group, which manages two funds that have invested in the biogas plant.

From waste to green energy and fertiliser

Willen Biogas will process approximately 25,000 tonnes of waste on an annual basis from households, restaurants, schools, universities and the food industry. Up until now, the waste has been deposited in landfills where it emits significant quantities of greenhouse gases while it decomposes.

Before the waste enters the biogas digester, plastic packaging and other foreign elements are removed in two stages. First the packaging is removed, and then the biomass undergoes a screening process in which small plastic particles and other foreign objects are removed from the biomass.

Then the waste is treated in the biogas plant in which biogas is generated that is used to produce CO2-neutral electricity. The biogas process converts all waste to a green fertiliser product, which the Williams family can use in the fields of Cattlegate Farm instead of imported fertilisers.

The excess heat is used to vaporise water from the fertiliser product. It reduces the volume and thus both the cost and CO2 emissions in connection with transport. The vaporised water is reused in the processes at the biogas plant so that the water consumption of the plant is minimised.

Satisfaction and pride at Xergi

“We are pleased that with our technology we can help to solve a wide range of environmental and climate challenges – and at the same time strengthen the local production of energy and fertiliser,” notes Jørgen Ballermann, CEO at Xergi.

“Meanwhile, we are thankful for the good cooperation with Willen Biogas and are of course proud of the fact that we have a very satisfied customer. We take it as an expression of the fact that we have a well-trimmed concept for both design of the biogas plants and the planning and construction process that are to get the biogas plants under way,” he says.


For further information, contact

Jørgen Ballermann, CEO, Xergi – tel: +4599351600 – jba@xergi.com

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