4 - Conclusions on Anaerobic Digestion

Part of: Anaerobic digestion

Area of Expertise:

On-farm anaerobic digestion and choice of system for AFBI Hillsborough.

Within Northern Ireland’s housed livestock, cattle produce the greatest volume of manure that is potentially available for on-farm anaerobic digestion (AD). On-farm AD of manures produced by housed cattle within Northern Ireland has significant potential to produce renewable energy and to assist in managing plant nutrients available in the manures. Due to the many, as yet unknowns, wide scale adoption of on-farm AD within Northern Ireland cannot yet be recommended. An on-farm AD will be installed at AFBI, Hillsborough as part of the AFBI Renewable Energy Centre. The feasibility and precise requirements for on-farm AD in Northern Ireland will be determined by research work with this digester. Because the on-farm digester at Hillsborough will be used for research, the specification of the system will include technologies that may or may not be required at farm level. The following summarises the specification for the on-farm AD at Hillsborough that will be used to research the feasibility of on-farm AD in Northern Ireland:

  • Utilise dairy cow slurry – in the first instance
  • Be single stage mesophilic with the capability of inclusion of a second stage digester at a later date
  • Will include ability to add material such as farmyard manure and crop residues
  • Will include the ability to pasteurise and chop feedstock
  • Will include a pre-mixing system for feedstock
  • Will be capable of including additional pre-treatment processes at a later date
  • Will include a centrifugal separator
  • Will include a biogas cleaning system
  • Will include a combined heat and power (CHP) unit for producing electricity and heat energy from biogas