Critical factors and their effects on product maturity in food waste composting

Product maturity represents the efficiency of composting performance, and it calls for high attention in food waste composting. In this study, a 24-1 fractional factorial design method combined with well-controlled experiments was introduced to characterize the effects of system factors (i.e., C/N ratio, aeration rate, starting culture amount, and coal ash amendment) on product maturity of food waste composting. The compost maturity was synthetically evaluated by developing a Mamdani fuzzy rule-based inference system. Temperature index, O2 uptake rate, ammonium, OM loss, C/N ratio, and ash content were chosen as indicators of the fuzzy multicriterion maturity evaluation. Evaluation results of compost maturity for the eight experiment runs demonstrated that the proposed method is capable of evaluating the compost maturity in food waste composting. The effect analyses indicated that the starting culture amount and aeration rate contributed the most to the compost maturity in this study. The results could provide decision support for the process control in food waste composting management.