Cocomposting of Crawfish and Agricultural Processing By-Products

Disposal of crawfish processing residuals (hereinafter, referred to as crawfish residuals) poses a challenging problem to the rapidly expanding crawfish industry. Cocomposting is examined as a waste management alternative to landfill disposal. Four agricultural processing by-products were evaluated for use as bulking agents in composting crawfish residuals: wood chips, rice hulls, bagasse, and bark. Approximately 5 to 6.5 volumes of each bulking agents were mixed with one volume of crawfish residuals in 0.3-m³ composting reactors. Compost temperature was continuously monitored, and moisture content was maintained within a desirable range. Samples were collected twice weekly throughout the 50-d composting process. Use of bagasse as a bulking agent led to the largest reduction in volatile solids (27.6 percent), organic C (55.3 percent), particle size (64.7 percent), and compost volume (52.8 percent). Finished compost using bagasse contained the greatest concentration of N (18.4 g N/kg and 160 mg NH₄-N/kg). Self-heating patterns and decomposition of crawfish residuals were satisfactory using all four bulking agents, and no odor, insect or other nuisance problems were detected. The finished products of all compost mixtures were suitable for use as mulch or reuse as bulking agents.