What is anaerobic digestion?
Anaerobic digestion (AD) is the term applied to the process of the biological breakdown of organic material in the absence of oxygen.
During the process organic matter such as food waste is broken down biologically and this generates large amounts of biogas; the gas is mainly made up of methane and carbon dioxide.
The process is similar to that which takes place during composting but unlike that process it is done in the absence of oxygen and the methane generated is captured and utilised as a biogas rather than being lost to the atmosphere.
The biogas generated by PDM’s AD plants will be used as a fuel for combined heat & power engines to generate heat for the processing site and for the generation of renewable electricity. The electricity will be used on the site in place of imported power and the excess exported to the national grid.
By using biogas from the AD process as a fuel the PDM plant will be displacing the use of fossil fuels; this in turn reduces the amount of carbon dioxide released into the atmosphere.
As well as producing biogas for the combined heat and power units, the AD plants will also produce a mineral-rich liquid fertiliser for use by local arable farms.
The planned AD units will complement PDM Group's existing renewable energy generation and rendering plants.
The combination of the three complementary technologies will enable PDM Group to provide a unique range of food waste recycling services to the UK market.
.....
Read more about PDM Group's national food waste recycling services»
Read more about PDM Group's renewable energy operations»
.....
Click here to download the food waste collection & recycling service information sheet 
[133KB]
News - May 2008
PDM Group launches national Anaerobic Digestion plant network to recycle food waste
PDM Group has announced an ambitious plan to become the UK’s largest anaerobic digestion (AD) plant operator, beginning with an AD plant at the company’s headquarters in Doncaster.
PDM Group has submitted a planning request for the plant, which, if approved, will be the first in a national programme that will see the Group building AD plants alongside the company’s existing food waste processing facilities which already operate throughout the UK.
The company collects unsold or unusable food products such as animal by-products from most of the UK’s major retail chains; these products are recycled to produce bio-fuels or to generate renewable energy.
The new plant would become operational in 2009, processing approximately 50,000 tonnes of food waste per annum, which will be collected from local shops, restaurants and cafes as well as residues from PDM Group’s petfood production plant.
The system, which is being developed in partnership with one of Europe’s largest AD plant operators, will enable PDM Group to generate 2MW of renewable energy, which will be used to power the Doncaster plant and supply the national grid.
PDM Group ‘s Commercial Director Philip Simpson says that the development is an essential one if PDM is to retain its position as the UK’s most successful food waste processor. He says: “An increased demand for sustainable food waste recycling, and the proposed additional ROC [Renewable Obligation Certificate] credits have made anaerobic digestion a key component in PDM Group’s range of food waste recycling services.”
Additional AD plants are planned for PDM processing sites in the South West, South East, London, Midlands, North West and Northern England.
The plants will complement the company’s growing renewable energy generation portfolio; recent developments have seen construction commence at the Nuneaton renewable energy plant and planning consent is being sought for an increase in production capacity at the Widnes plant.
The Widnes expansion will more than double the site’s renewable energy generation, which is already powering over 25,000 homes in the North West.