A 5MW farmer-owned AD plant in Suffolk has chosen HRS Heat Exchangers to supply a new system to pasteurise its digestate; the valuable organic biofertiliser produced by the process.
Agri-Gen, which is based near Woodbridge in Suffolk, is owned by a consortium of six local farmers who locally grow some 22,000 acres of arable and root crops, such as potatoes, carrots, parsnips and sugar beet. The AD plant is fed with a mixture of agricultural materials including rye, sugar beet, beet pulp, vegetable out-grades and maize, although the farms try to minimise the amount of maize grown. The energy produced by the plant is used, amongst other things, to dry and cold store crops such as potatoes and onions.
Since it began producing biogas four years ago the company has focused on expanding and running the plant, but is now in a position to carry out a number of improvements to the process, including the additional of pasteurisation to improve the biosecurity of the digestate fertiliser which is returned to the farms’ fields. The HRS 3-Tank Batch Sludge Pasteuriser will treat the digestate between the main digester and storage. The use of a three-tank system means that while one tank is being heated and pasteurised, another is being emptied and the third is being filled, which results in a continuous operation.