Considerations for Co-digestion in Agricultural Anaerobic Digestion

Anaerobic digestion (AD) of livestock manure can be supplemented with additional agricultural or industrial organic waste, potentially adding sources of revenue through tipping fees and additional biogas production. However, quantifying the anticipated impact on digester performance and operation is challenging, particularly as some potential feedstocks have not been studied previously. Through a series of lab-scale mono- and co-digestion biomethane potential tests, we have characterized several feedstocks currently in use at a mixed agricultural AD facility. In addition, we examined the potential synergistic or antagonistic impacts on methane yield and rate of methane production. There are indications that some feedstock combinations do have synergistic effects on the rate of methane production. These results can help inform current or future agricultural AD operators regarding the use of co-digestion feedstocks and best practices in selecting new feedstocks for co-digestion.