Physical, chemical and biological processes for optimizing decentralized composting

On-site composting of nonpolluted organic wastes avoids costs and energy for transportation since the volume to be transported can be reduced to about 20% of the original. This paper describes the aerobic processes in a small-scale composting reactor, and evaluates how these processes can be optimized. The optimized composting process has a relatively short turnover time for organic matter; at the same time the temperature of about 60degreesC decreases the problems with pathogens and weeds in the mature compost. The compost produced has a high nutritional value, with high concentrations of especially nitrogen, potassium and phosphorus, while the contamination by heavy metals and other toxic substances are very low.