Process optimization of dry batch anaerobic digestion of municipal solid waste

Abstract

Optimizing anaerobic digestion aims to maximize organic waste stabilization at short
digestion period with higher biogas production. This paper presents different strategies to
optimize the anaerobic digestion of organic fraction of municipal solid waste in combined
process in which early flushing and microaeration were conducted during pre-stage, Also, the
influence of substrate particle size reduction and the advantage of thermophilic system over
mesophilic in the overall digestion process are presented, Additionally, an attempt was taken
to employ sequential staging concept by using a mature (old) reactor which underwent a
combined digestion process. Importantly, process evaluation between an optimized combined
process and sequential staging concept were evaluated with the main objective of optimizing
the process, Process efficiency evaluation was based on biochemical methane potential
(BMP) test The overall result suggest that the combined anaerobic digestion process can be
optimized by conducting shorter duration of pre-stage at reduced volume of flushing water
with microearation, under thennophilic condition at reduced substrate particle size of 30 mm,
Nevertheless, the sequential staging concept offers an improved operation over the combined
anaerobic digestion wherein the higher specific methane yield of 11.9 L CH4/kg VS.day was
achieved, Improved waste stabilization with 86% and 79% mass and volume reduction which
corresponds to 84% process efficiency was obtained by sequential staging process,