A method for evaluating and verifying biochemical methane potential test completion performed with landfilled municipal solid waste.

Abstract

The biochemical methane potential (BMP) test is significant for the landfill industry as it provides a means to evaluate the gas potential, and therefore potential degradability, of both incoming and in-place municipal solid waste (MSW). However, the BMP test is not standardized making comparison of BMP results across sites problematic. For example, the BMP test duration has historically ranged from 20 days to several months with most current BMP tests lasting 60 days. However, the gas generation data can potentially be modelled for any of those durations to produce a prediction of the ultimate BMP value (BMP_ULT). Currently, the predicted BMP_ULT values of 23 long-duration (115-150 days) BMP tests were used to determine the required quantity of data (i.e. number of days) needed to produce an accurate BMP_ULT prediction. Results showed that no single test duration produced both accurate and efficient results, so a novel performance-based endpoint was proposed. The relative change in predicted BMP_ULT values with respect to time (dBMP_ULT/dt) was chosen as a potential performance-based completion metric. Results indicate that once the absolute normalized dBMP_ULT/dt value is within <2.5, <1.5 and <0.6% day^-1 that the predicted BMP_ULT is within 20, 10 and 5% of the true BMP_ULT, respectively. Overall, the use of performance-based metrics for determining BMP test completion will allow for the collection of partial data sets, reduced experimental times and verification of results.