Reuse and recycling techniques
Pages 54

Composting can provide animal producers with a convenient method for disposing of animal mortalities and also provide a valuable soil amendment. In addition, the finished compost can be stockpiled and reused to compost other mortalities. Composting is a natural decomposition process conducted by microorganisms that happen under controlled conditions. It reduces the size of the material by removing organic products, water, and energy as carbon dioxide, steam and heat. Also, the pathogens are destroyed by the high temperatures reached during the composting process, which require time and space, and some specialized equipment may be necessary. If the process is not done correctly, pathogens survive and odors may occur, attracting flies and vermin, as well as vultures that can uncover the carcasses. Composting of organic wastes is a biooxidative process involving the mineralization and partial humification of the organic matter, leading to a stabilized final product, free of phytotoxicity and pathogens and with certain

mortality disposal method, its use is declining due to groundwater and soil contamination concerns. Frequently composting is being adopted as a viable method for in situ treatment of livestock carcasses. Because the successful use in the poultry and swine industry, it is perceived to be an economical and environmentally friendly process. The high temperature acquired through microbial metabolism has potential to inactivate pathogens. Therefore it has been used for pathogen related carcasses disposal in USA and Canada. Glanville et al. (2006) reported excellent viral pathogen inactivation and animal tissue decomposition using a windrow type cattle composting system. Previous researchers reported animal tissues (internal organ and soft tissues) were fully decomposed in 4-10 months in windrow type composting systems (Glanville et al., 2006; Sander et al., 2002). They observed and determined animal tissues decay extent during excavating composting piles. Properly estimated carcass decomposition rate is valuable for designing and controlling animal mortality composting systems. However, it is still difficult to evaluate the decomposition rate inside of the field scale compost piles. Every year, Unesp (São Paulo State University) needs to dispose about 540 tones of this waste and the composting seemed to be the most sustainable alternative. In this study, 750 kg of carcasses were composted in two compost boxes with damp peanut hulls and tree pruning as cover materials. These carcasses are from teaching and researching activities of the university veterinary hospital.