HMP Guys Marsh Bioplex Anaerobic Digestion Plant

Background Bio waste and in particular food waste is a challenge that the Prison Service is facing and the Bioplex system installed at Guys Marsh is the first of it’s kind. Previously, such waste matter was compacted and sent to Landfill.

Process All such matter is now passed through a shredder and fed into feedstock tanks. After a three day pasteurisation period, the contents of the tanks are emptied. Solid material is sent to the Farms for a 21day maturing period before being re-used as compost. The water content from the tanks is re-pumped via a Bio Gas tank for re-use in the pasteurisation process and the resultant gas is stored ready for use within a power generator, which is soon to supply electricity to adjacent greenhouses.

Additional benefits Fundamental to the process is the employment and training of prisoners to carry out this work. Prisoners have benefitted from gaining first hand experience of waste management and associated skills such as operating equipment and recording recycled material. The Bioplex is now part of an educational process, linked to the Kitchen Garden and NVQ food production within the Main Kitchen.