Modelling of the biodegradation of organic matter in municipal landfills

A model is presented to simulate the biodegradation of easily and slowly hydrolyzable organic matter, as well as the generation of biogas and heat release. The model is based on fundamental relationships among physical/chemical, thermodynamical and microbial processes occurring in municipal landfills. Local, microbially-mediated degradation processes occurring in municipal landfills, are simulated in terms of the hydrolysis of solid organic matter, the formation of glucose and acetate as intermediary carbon substrates and the generation of the biogases CH4 and CO2. Thus, the overall decomposition of the organic matter has been assumed to follow four sequential biochemical reactions: hydrolysis, acidogenesis, acetogenesis and methanogenesis. In order to study the impact of environmental factors on the biological decomposition processes, pH, temperature and hydrogen changes have been integrated into the degradation model as inhibition terms.