Woonton Civil Engineers and Building Contractors first started work on the Biogas installation in September 2012. Due to the natural ground conditions, the site required stone piling to stabilise the site. The winter of 2012/13, was very wet and cold, the more preparation work we did, the wetter the site became. Once the site was levelled and the drainage systems introduced, we could get on with commencing construction. There were times when the weather was too cold for the plants to supply concrete, but we managed to keep to schedules and continue operations.
Once the silage clamp, measuring 85m x 60m was constructed incorporating 3.8m high, mass concrete walls we could continue with the construction of the tank bases within the bunded compound area. The largest digester tank within on the compound sat on a 22m diameter circular concrete base. There were other numerous concrete bases, together with a steel frame building used to process the raw vegetable material pulp. The whole compound area was then concreted within a bund wall to satisfy the environment agency requirements. The construction of the AD plant was completed within 18 months.
The plant went operational at the end of 2013 and produces 11 million kilowatt hours of electricity per year. It is located at one of the top‐four potato processing sites in the UK supplies produce to leading national retailers. The site was officially opened on 1st May 2014 by Andy Clarke, Asda's President and CEO.
Anaerobic digestion plants use a series of natural biological processes to break down organic waste material anaerobically (in the absence of oxygen) and convert it into biogas, which can then be used to create electricity in a CHP (Combined Heat and Power) unit, put into the electricity grid, or used to power vehicles. The only other by-product of AD is a natural fertiliser and soil conditioner suitable for agricultural use.