Aerobic thermophilic composting of piggery solid wastes

Aerobic static pile composting of piggery solids was investigated at a 5 m3 scale. Sawdust was used as the bulking agent to provide additional carbon and to increase the porosity of the substrate. The temperature profiles indicated that the solid waste could be pasteurised completely. The nutrient analysis showed that 79% of initial nitrogen was conserved in the compost while there was no significant change in phosphorus concentration. The microbiological assays revealed that there was a four orders of magnitude decline in Enterococci counts while the MPN counts decreased by three orders of magnitude suggesting there may be spore-forming bacteria surviving the composting process.