Bedfordshire based Zoedale Plc has been involved in a number of Anaerobic Digestion & Biogas projects and supplied ATEX approved Electric Actuators, Pneumatic Actuators, Ball Valves, Butterfly Valves and Solenoid Valves from stock. This is how the AD process works:

In the UK 15 Million tonnes of food is wasted every year with 7 Million tonnes of this coming from households. Our throw away culture and 2 for 1 offers from the big supermarkets is partly to blame but what can be done to reduce the environmental impact? Many UK Councils have introduced a food waste bin for recycling. Some of it will be composted but a large proportion will be turned to Energy in Anaerobic Digestion plants like the one pictured. By using food waste as a source of power this material is diverted from over flowing landfill sites. When food rots down in landfill it gives off Methane, a powerful greenhouse gas 25 times more potent than carbon dioxide. By capturing the Methane in Anaerobic Digestion plants and using it for energy, our need for burning fossil fuels is reduced, saving even more carbon. So it’s a very “Green” process!

The Anaerobic Digestion process is part of a biological waste treatment method used commonly in waste treatment plants around the globe. The only difference is that instead of releasing the gases in to the atmosphere, they are collected and utilised as fuel.

In the biogas production system, food wastes, animal manure, liquid and solid organic wastes are fed into a digester where an anaerobic process using bacteria ferments the waste and produces Biogas. What’s left in the digester is collected as sludge that can later be returned back to farm land as a fertiliser. After the digestion process any liquid in the waste treatment plant will be rendered sufficiently harmless to the environment and safe to be discharged into the rivers.

Typically, the Biogas produced in a plant will produce:

  • Methane 60% - 70%
  • Carbon Dioxide 30% - 40%
  • Trace amounts of Hydrogen SulphideBio plant

This mixture of gas is further processed so that the Carbon Dioxide and Hydrogen sulphide gases are removed. The result is a gas consisting of mostly Methane. This is very similar to the Natural Gas we get from our North Sea Gas fields.

By using compressors in a bottling plant the gas can be stored under high pressures in cylinders or transpoted. Much of the biogas can be used for fuel in vehicles, electrical power generators and for other heating purposes.

With natural Oil and Gas reserves running low, the crisis in Ukraine / Russia and the UK’s reluctance to take advantage of Shale Gas, this method of fuel production is becoming very important in terms of Energy Security.