Modeling Anaerobic Degradation in Municipal Landfills

Abstract

Based on conceptual considerations dealing with anaerobic reaction processes, a model is presented to simulate the biodegradation of easily hydrolyzable solid organic matter, and the generation of biogas and heat release. The model is based on the fundamental relationships between physical, chemical, thermodynamic, and biological processes that occurring in municipal landfills. Local microbially mediated degradation processes occuring in municipal landfills are simulated in terms of the h ydrolysis 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 three sequential biochemical reactions: hydrolysis, acidogenesis, and methanogenesis. To study the impact of environmental factors on the biological decomposition processes, pH, temperature, and oxygen changes have been integrated into the d egradation model as reaction influencing terms. In a first investigating step the timedependent change of different components (e. g., organic substrates, gases, biomass, and temperature) is simulated by the model for a locally representative unit volume without convective transport.