Composting Process Model Considering Both Ventilation by Changing Gas Composition and Moisture Transfer by Water Potential

Abstract

Composting process modeling is necessary to design and operate a passive control composting tank. The model for the passive control composting process has been developed, which considered natural ventilation by changing gas composition and moisture transfer by water potential. The effect of water produced by microorganisms was also considered in the model. In order to evaluate the rate of water produced, water evaporation speed and ventilation rate in the model, experiments were performed with a passive aeration composting tank in a controlled laboratory condition. The down flow of air was caused by increasing CO2 concentration in the first stage of the composting. If the air flow direction was not changed from down flow to up flow by temperature rising, the results showed that the degradation was slowed down and odor was produced. Comparisons of experimental and simulation results for temperature and ventilation rate in general showed good agreement during the whole duration of the process in the passive control composting tank. Keywords : Composting, Modeling, Gas Composition, Water Product, Water Potential堆肥化，モデリング, 気体組成，水分生成, 水分ポテンシャル Associate Prof.,

Laboratory-scale Experiment for an Active-stage Composting Process under the Same Material and Operating Conditions

“…Recently proposed detailed simulation models (Sole-Mauri et al, 2007;Bongochugetsakul and Ishida, 2008;Hiraishi et al, 2012;Nakayama et al, 2007a;Nakayama et al, 2007b) show an increased recognition of the effectiveness of using unused biomass along with an upgrade in the numerical techniques being used. Although sensitivity analyses have been applied to these models, confirmation of their reproducibility has been insufficient, and further research is required to bring them up to the level required for effective practical use.…”