Bio-methane potential tests to measure the biogas production from the digestion and co-digestion of complex organic substrates.

Abstract

Bio-methane potential (BMP) tests are widely used in studies concerning the anaerobic digestion of organic solids. Although they are often criticized to be time consumer, with an average length longer than 30 days, such tests are doubtless easy to be conducted, relatively inexpensive and repeatable. Moreover, BMP tests give significant information about the bio-methanation of specific substrates and provide experimental results essential to calibrate and validate mathematical models. These last two aspects have been handled in this work where the following elements have been de- scribed in detail: i) the methods used to conduct the BMP tests; ii) the cumulative bio-methane curves obtained from three BMP tests, concerning respectively two pure organic substrates (swine manure-SM and greengrocery waste-GW) and an organic substrate obtained by mixing buffalo manure (BM) and maize silage (MS); iii) the procedure used to calibrate a mathematical model proposed by the authors to simulate the anaerobic digestion process; iv) the results of the calibration process. This paper shows that BMP tests are extremely helpful to determine the amount of bio-methane obtainable from different organic solids and under different operational conditions as well as the biodegradability of the investigated sub- strate, the relative specific rate of bio-methanation and the synergic effect of multiple co-digested substrates. Furthermore BMP tests represent an interesting tool for the technical and economical optimization of bio-methane producing plants.