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Winner of 'Best AD Plant' chooses ADBA member Gas Data


Fernbrook Bio uses food waste from local authorities and other outlets to produce electricity through the anaerobic digestion process. The company’s Rothwell Lodge biogas plant is located near Kettering and accepts 30,000 tonnes of segregated food wastes from homes and businesses in the surrounding area. Rothwell Lodge won the ‘Best Anaerobic Digestion Project 2012’ at the first UK AD & Biogas Industry 2012 Awards.

Initially, a gas analyser was installed as part of the construction of the plant, but when it was due to be serviced, the site manager had a bit of a shock.

Carl Woolley, Rothwell Lodge Site Manager, said:

The gas analyser was supplied by a German company, and when it came to having an annual service we were quoted a price which meant after 2-3 years we could have bought a completely new system. It just wasn’t practical. We looked at the market and different types of analyser and we liked the idea of the Gas Data Click! System where we can just change small parts as required instead of larger more expensive ones. We are able to get the unit serviced locally, the parts are smaller and easier to change and I am able to manually select which sample point I want to test.

Gas analysis is crucial to Fernbrook’s business.

Carl Woolley:

The digesters are just like giant stomachs, if you over feed them the gas quality drops and if you under feed them the gas quality goes up. This fluctuation can cause problems with the combined heat and power (CHP) engines, so we need gas analysers to help us maintain the engine performance.

If our methane quality changes too much the CHP can’t cope and then turn off, so we lose power generation – and money. Also, if our hydrogen sulphide (H2S) content is too high, it creates more wear on the engines and our service costs get higher.


We are able to see our methane content which is one of the first indicators on how well the digester is working , it also tells us our H2S content so if this gets too high we can add chemicals to our digester to reduce the amount and save on damage to our CHPs.

Fernbook now have two digesters on site and planning permission for a third, so they can increase the site capacity to 45,000 tonnes per year.

Carl Woolley:

This gives us a higher return on gate fees and more power production whilst also reducing waste going to landfill and helping the environment.

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