Evaluation of an aerobic composting process for the management of Specified Risk Materials (SRM)

In Nova Scotia (NS), approximately 2700 tonnes of Specified Risk Materials (SRM) are produced annually. SRM disposal is a serious concern for abattoirs and the beef industry. Composting offers a low risk and simple means to transform raw SRM into a more stable and easily managed material. In this project, wheat straw and sawdust were used to compost with SRM on a pilot scale. The study evaluated changes over time in total carbon, total nitrogen, pH, temperature, moisture content and electrical conductivity. Compost temperatures in all treatments met the Canadian Council of Ministers of the Environment (CCME) guidelines for pathogen kill. The compost maturity tests showed that the evolution of CO(2)-C in all the final compost products was less than 1 mg g(-1) organic matter day(-1). Wheat straw performed well as a composting feedstock for raw SRM as sawdust. While the wheat straw has advantages including greater availability, lower cost and easily decomposable carbon compounds more management is required to maintain adequate compost temperatures. The influences of seasonal variations due to temperate climatic conditions on SRM composting were also studied with wheat straw. The results suggest no significant differences in composting effectiveness between the two seasons.