*WINNER* Assessing the Impact of Different Inoculum Sources on Specific Methane Yield of Biomethane Potential Tests

Abstract

A Biomethane Potential (BMP) test is a simple and inexpensive technique that determines the biodegradability of a specific substrate, while also evaluating the potential amount of methane that can be produced within the anaerobic system. It is the first fundamental assessment in determining the amount of biogas generated from an anaerobic digestion system. First proposed in 1979 by Owen et al., inoculum from an established anaerobic digester is mixed with a proposed substrate in an oxygen free environment within a batch reactor. The biogas and methane content are then measured over the course of the testing period to determine methane production potential. Although BMP tests have been conducted for years, due to lack of a standardized method there is often inconsistencies in results between similar BMP studies. The source of the inoculum used in BMP tests is one parameter that remains inconsistent among studies. The microbial communities in different inoculum sources can vary. This can greatly affect the overall methane yield of the BMP test. Therefore, the objective of this study was to evaluate specific methane yield variability in the BMP test using inoculums from wastewater, agricultural, and industrial anaerobic digesters. Results indicated that inoculum source did not have an effect on specific methane yield. However, inoculum sources that had been adapted to similar substrates had a higher rate of reaction. Therefore, if speed of reaction is a necessary requirement during methane production, a well-adapted inoculum source should be considered.