Sustainable Production of Compost from Animal Waste Using an In-vessel Bioreactor: A Health Policy Brief

Abstract

Background: Livestock manure, particularly from cattle and poultry, represents a major source of organic waste, and improper disposal can pose significant environmental risks. Composting offers a sustainable solution by stabilizing manure, enhancing nutrient availability, and reducing pathogen load. Objectives: This study aimed to evaluate the effects of biochar amendment and varying cattle-to-poultry manure (CM/PM) ratios on compost quality, pollutant removal, and microplastic dynamics. Methods: Twelve treatments combining three CM/PM ratios (1:1, 3:1, and 1:3) with biochar levels (5%, 10%, and 15%) were composted under controlled aerobic conditions. Physicochemical properties, nutrient dynamics, heavy metals, and microplastics were monitored throughout the co-composting process. Results: Biochar significantly improved compost maturity, humification, nutrient stabilization, and pollutant reduction, with total organic carbon, humic acid content, and C/N ratio showing enhanced trends in biochar-amended treatments. Heavy metal removal efficiencies increased with biochar, while microplastic abundance decreased moderately. Conclusions: These findings demonstrate that animal manure compost produces environmentally safe, nutrient-rich compost, offering a practical strategy for sustainable waste management, soil fertility improvement, and circular bioeconomy promotion.