Organic fertilezer production by industrial composting of agricultural industrial wastes

Abstract

Several mixtures of agricultural industrial wastes (sugar cane husks, coffee and cotton wastes) were composted in static piles of 30-40 m3 each. All residues are easily degradated which allows several different mixture composition tor the future full scale production. All mixtures attained thermophilic stage in short period (3-5 days). After 6 months of composting, the final products have good agronomic characteristics. Vinasse low pH levels (3,0 - 3,5) did not restrain microbial activity. The pH of mixtures increases rapidly (3-4 days) followed by stabilization above 6,5. This composting technology needs low investiments and allows production of low cost organic fertilizer. Aeration based on mechanical turning up and natural air diffusion through composting mass is the most important limiting factor observed. It restricts microbial activity in all mistures and leads to a long stabilization period (6 - 7 months).