Composting of Food Waste and Mixed Poultry Manure Inoculated with Effective Microorganisms

Abstract

Food waste and poultry manure mixes inoculated with effective microorganisms (EM) were composted by a rotating drum composter under initial moisture conditions of 63-74% (w.b). Composting was performed for 24 hrs using steam from a firewood boiler (450MJ/hr) which heated the composting mass in order to maintain the temperature of the compost between 60 and 80°C. Parameters monitored over this period included the nutrient content, heavy metal content, maturity and stability indices etc. Changes in pH, moisture content, EC (electrical conductivity), NaCl and C/N during composting were consistent with those generally observed in ordinary composting systems. The parameters were influenced by the feedstock materials but not affected by inoculation with EM. The C/N ratios and moisture content of the composts decreased with the composting time. The NaCl content of the food waste compost increased with composting time but was less than 1.0% (d.b). For the finished food waste compost, the compost stability index, based on oxygen uptakes, was less than 0.3 mg/ g VS· hr and the compost maturity index, based on seed germination rates, was greater than 80%. The finished food waste compost could be utilized for land improvement whereas that using food waste amended with poultry manure could not be utilized.