Animal residues

Cattle, chicken and pig waste can be converted to bio-energy by conversion to gas or burning directly for heat and power.
Obtaining bio-gas from animal waste is carried out in an Anaerobic Digester (AD) The AD plant can be regarded as part of an integrated waste management plan and can assist farmers in complying with legislation on the safe handling of waste : the process stabilises slurries, making them easier to handle and can reduce the odour by up to 80%.
Improving the efficiency of waste management will also help to reduce the risk of land and water pollution by reducing and controlling residues. The remaining nutrients in the solid residue and liquor can be returned to the farms and used as a fertiliser, educing the need for inorganic fertilisers.

Anaerobic Digesters - the process
Anaerobic digestion (AD) is a process which enables organic matter is broken down by bacteria in the absence of air. Organic matter is placed in a digester (a warmed sealed airless container) for between 10- 25 days. The materials ferment and produce a gas (methane), a solid called the digestate, which in turn can be separated out into fibre and liquor. Once cleaned of contaminants, the biogas can be used in a furnace, gas engine or turbine or further refined for use in gas powered vehicles and CHP plants. The digestate can be returned to the farms for re-use as a soil conditioner and fertiliser.
The AD plant can operate on a small scale, recycling slurry products at an on-farm facility run by an individual farmer or at a larger scale development at a centralised anaerobic digester, taking feedstock from local farmers and food processors and marketing the products on a larger scale.

Targets for the North West have been established for Anaerobic digestion including the following: