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| An anaerobic degradation model for landfilled municipal solid wastes considering effects of pH and VFA |
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Abstract A two-stage anaerobic degradation mechanistic model was developed to describe degradation processes and behaviors of municipal solid wastes (MSWs). Primary environmental factors, including moisture content, VFA and pH, were considered in this model. In order to simulate degradations in different leachate acidified situations, effects of unionized VFA and pH on methanogenesis were considered separately. An equation calculating leachate pH under high CO2 atmospheric pressure was presented, and an approach for estimating CO2 pressure in landfilled conditions was provided. The effectiveness of this model was demonstrated by simulating a degradation experiment of MSWs. Finally, analyses were conducted with the presented pH calculating equation. Results showed that high CO2 pressure in landfilled environment affected leachate pH remarkably; a consistent correlation between pH and VFA at different acidified levels was not available; under highly acidified condition leachate pH was not sensitive to VFA concentration change and the inhibition caused by unionized VFA was considerable.
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Received: 26 March 2014
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