Anaerobic biodegradability of cellulose and hemicellulose in excavated refuse samples using a biochemical methane potential assay

Abstract

Improved techniques are needed to predict potential methane generation from refuse buried in landfills. The Biochemical Methane Potential (BMP) test was used to measure the methane potential of ten refuse samples excavated from a Berkeley, CA, landfill. The test was conducted in 125-ml serum bottles containing phosphate-buffered medium and inoculated with anaerobically digested sewage sludge. Comparison of the measured BMP to the theoretical BMP calculated from measured cellulose and hemicellulose concentrations indicated that cellulose plus hemicellulose is not well correlated with the measured BMP. The average of the measured to theoretical BMP was 19.1% (range 0-53%, s.d. = 16.9%). Measured sulfate concentrations showed that sulfate was an insignificant electron sink in the samples tested. Once methane production from the refuse was complete, 0.072 g of Whatman no. 1 filter paper was added to two of the four serum bottles incubated for each sample. An average of 84.9% (s.d. = 2.5%) of the added filter paper was recovered as methane, suggesting that some cellulose and hemicellulose present in refuse is recalcitrant or otherwise not bioavailable.