Co-digesting Poultry Litter with other Animal Wastes
Co-digesting poultry litter with another liquid manure can alleviate the low moisture content issue commonly existing in the litter that renders anaerobic digestion difficult to proceed. Similarly, many of the past reports mainly focused on co-digestion of poultry manure (rather than litter) with different liquid manures such as swine and dairy manure, with little information related to poultry litter co-digestion. An exciting fact observed by past researchers was that inclusion of poultry manure during anaerobic digestion of swine manure produced more methane and biogas than swine manure alone. However, some dilution of poultry manure was performed in this case which could mask the results due to the reduced ammonia level in the substrate. Therefore, in this project, different mixing ratios of poultry litter and either liquid swine or dairy manure will be investigated to determine the feasibility of this technology based on biogas production, methane content in biogas, volatile solids destruction, COD and BOD reduction. Another benefit of co-digesting these wastes is that the potential increase in the substrate C/N ratio can actually help improve the performance of the anaerobic digestion process. The best operating parameters including C/N ratio, temperature, pH, hydraulic retention time, and organic loading rate will also be determined for the digestion process.