Resource Conversion through Composting of thermo-chemically Treated Buried Carcasses by Mixing with Kenaf and Rice Straw

Objectives In this study, thermo-chemically treated carcasses from livestock burial sites were composted, and kenaf and rice straw were used as moisture control agents for composting. Changes in the characteristics of the compost pile for 60 days were observed, and the physico-chemical characteristics of the comopost were analyzed after the end of the experiment to evaluate the potential for recycling of buried livestock carcasses through composting. Methods The compost pile was prepared by mixing the treated carcass with kenaf and rice straw in the ratios of 7:3, 6:4, 2:1, and 1:1 (V/V), respectively. Samples were collected on days 0, 7, 15, 30, 45, and 60 after deposition to analyze temperature, pH, and EC. The emissions of the three gases H2S, NH3 and CO2 generated were measured. After composting was completed, the characteristics of the compost pile were identified through physicochemical analysis. Results and Discussion After the initial mixing of raw materials, the temperature increased in all treatment areas after the initial stage. The initial pH of composting was strongly alkaline, then gradually decreased and stabilized on the 50th day of composting. H2S and NH3 are mainly generated in the early composting stage and decreased rapidly. CO2 reached its maximum concentration on day 15 and then decreased. After the end of composting, the nitrogen, phosphorus, and potassium contents increased compared to before composting. In all compost piles, the organic matter content was over 30%, the moisture content was 4.3~5.9%, and the organic matter to nitrogen ratio was 65.3~82.9. Escherichia coli and Salmonella were not detected in all compost piles. The maturity of compost piles in which carcass and Kenaf were mixed in the ratio of 2:1 and the compost bed in which carcass and rice straw were mixed in the ratio of 6:4 and 1:1 were over 70, showing acceptable maturity. Conclusion In this study, the recycling potential of livestock burial samples through composting was evaluated. Physico-chemical analysis has shown that kenaf or rice straw and carcass are to be mixed to form a compost pile that can be used as compost.