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A Simple Numerical Model for Predicting Organic Matter Decomposition in a Fed‐Batch Composting Operation
Author(s) -
Nakasaki Kiyohiko,
Ohtaki Akihito
Publication year - 2002
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2002.9970
Subject(s) - decomposition , organic matter , degradation (telecommunications) , carbon fibers , raw material , total organic carbon , food waste , biodegradation , lag time , pulp and paper industry , biodegradable waste , environmental science , waste management , chemistry , biological system , mathematics , environmental chemistry , computer science , engineering , organic chemistry , algorithm , biology , telecommunications , composite number
Using dog food as a model of the organic waste that comprises composting raw material, the degradation pattern of organic materials was examined by continuously measuring the quantity of CO 2 evolved during the composting process in both batch and fed‐batch operations. A simple numerical model was made on the basis of three suppositions for describing the organic matter decomposition in the batch operation. First, a certain quantity of carbon in the dog food was assumed to be recalcitrant to degradation in the composting reactor within the retention time allowed. Second, it was assumed that the decomposition rate of carbon is proportional to the quantity of easily degradable carbon, that is, the carbon recalcitrant to degradation was subtracted from the total carbon remaining in the dog food. Third, a certain lag time is assumed to occur before the start of active decomposition of organic matter in the dog food; this lag corresponds to the time required for microorganisms to proliferate and become active. It was then ascertained that the decomposition pattern for the organic matter in the dog food during the fed‐batch operation could be predicted by the numerical model with the parameters obtained from the batch operation. This numerical model was modified so that the change in dry weight of composting materials could be obtained. The modified model was found suitable for describing the organic matter decomposition pattern in an actual fed‐batch composting operation of the garbage obtained from a restaurant, approximately 10 kg d −1 loading for 60 d.