Two stages kinetics of municipal solid waste inoculation composting processes

In order to understand the key mechanisms of the composting processes, the municipal solid waste (MSW) composting processes were divided into two stages, and the characteristics of typical experimental scenarios from the viewpoint of microbial kinetics was analyzed. Through experimentation with advanced composting reactor under controlled composting conditions, several equations were worked out to simulate the degradation rate of the substrate. The equations showed that the degradation rate was controlled by concentration of microbes in the first stage. The degradation rates of substrates of inoculation Run A, B, C and Control composting systems were 13.61 g/(kg x h), 13.08 g/(kg x h), 15.671 g/(kg x h), and 10.5 g/(kg x h), respectively. The value of Run C is around 1.5 times higher than that of Control system. The decomposition rate of the second stage is controlled by concentration of substrate. Although the organic matter degradation rates were similar to all Runs, inoculation could reduce the values of the half velocity coefficient Km and could be more efficient to make the composting stable. Particularly, for Run C, the degradation rate is high in the first stage, and Km is low in the second stage. The results indicated that the inoculation was efficient for the composting processes.