Comparison of two laboratory methods for the determination of biomethane potential of organic feedstocks

Abstract

The increased interest in anaerobic digestion systems has led to the increased need for laboratories to conduct biomethane potential (BMP) to determine the possible usefulness of various feedstocks. There is currently no standard method, but two well established methods have emerged as standardized methods for BMP testing. These two methods are the Automated Methane Potential Testing System, or AMPTS and the German DIN standard method using eudiometers. While these are widely-used, there have been no comparison of how these systems relate to each other in terms of BMP results for identical feedstocks. This study compared the BMP results for ten feedstocks using both the AMPTS and DIN methods to see if the results can be directly related. Results suggest that the methods provide different BMP results for 8 of the ten tested feedstock (p<0.05). Each method has advantages in terms of using it for BMPs, but overall results suggest that users of these methods should be aware of method differences when comparing results between methods or labs. For those interested in determining BMPs for larger-scale projects they should choose a testing facility that has experience with both methods and understands the differences in results between methods. While both methods can provide valuable information, it is important to be cautious in interpreting the results of these methods when compared to each other and likely the many in-house methods that various labs have developed.