STUDY OF THE CO-COMPOSTING PROCESS OF MUNICIPAL SOLID WASTE AND SEWAGE SLUDGE: STABILITY AND MATURITY

Assessment of compost maturity or stability is important for successful use of compost in agricultural and horticultural production. The aim of this study consisted basically on the evaluation of several methods to determine the degree of stability and maturity of compost. The applied methods are microbial respira-tion and the measurement of several enzymatic activities for stability determination and biogermination test for maturity determination. These procedures have been applied to the monitoring of evolution of the process of compost of different urban waste: Pile 1, organic fraction of municipal solid waste (OFMSW); Pile 2, relationship in weight OFMSW/sewage sludge (2:1); Pile 3, relationship weight OFMSW / sewage sludge (1:2); Pile 4, sewage sludge. Piles were aerated by mechanical turning (windrow composting system).. There is a direct relationship between microbial respiration and several enzymatic activities, like dehydrogenase and phosphatase activities, and compost stability