Greenview Environmental announces new approach to biogas production

(20/12/2008)

According to Defra, the UK has fewer than 20 agricultural digesters producing electricity. According to John Jardine, founder and Chief Executive of Greenview Environmental, this is because everyone is under the illusion it is difficult and expensive.

Greenview Environmental has announced a new approach to biogas production and John Jardine explains that he went back to first principles in his design: “Anaerobic digestion is a natural process - the secret is creating and maintaining the right conditions. In my travels I saw simple home-based digesters where the contents of the family latrine provided gas to cook the dinner.

“I have incorporated the simplicity of this concept into the design of a combined aerobic and anaerobic organic waste refinery that overcomes many of the issues that have been holding back acceptance of this technology.”

Greenview Environmental is announcing an organic waste refinery that produces two valuable outputs from green-bin and category 3 organic waste collections – nutrient rich compost and biogas.

The innovative aspect is that Greenview runs the two systems in parallel. Its unique in vessel approach with Mistral aeration technology conforms to EU standards. By pulverising the waste to 12 mm to increase the surface area and then forcing air through the decomposing matter in an enclosed building it heats rapidly to 70°C killing all harmful microbes.

To create compost, the pasteurised matter is then moved to maturation bays where decomposition continues in warm, moist, aerated heaps ideal for the natural microbial action. However, at this point a proportion of the pulverised waste can be used as feed for the anaerobic digester. As it is already warm, all the energy it produces is then available to create electricity.

In the new plant, John Jardine has overcome one of the fundamental problems faced by other approaches to anaerobic digestion. “Our system uses source sorted material and then grades it. A carefully regulated parallel system means that oversize particles are mixed with fine ones, and wet material mixed with dry to create a consistent feed material. By creating a feed material with particles of less than 12mm there is a large surface area available for microbial action and this promotes fast anaerobic digestion which is a challenge for other systems.”

Any large matter is pulverised by a Tollemache specially modified by Greenview to take organic material so there is very little that cannot be processed. The Greenview Tollemache can run on bio-electricity so in addition to being quiet and clean, the organic waste refinery can be self-sufficient for energy.

Another benefit of a combined approach is that reduces the amount of waste-water produced by the anaerobic process. Liquid is reused by the system and bio-filtered reducing both the volume and cost of storage.

Related categories:  Biodegradable waste   Biofuels and biomass   Environmental technologies for Residential and Green homes