Desempenho de um reator para compostagem descentralizada de lixo orgânico domiciliar e grau de maturação do composto

Abstract

In recent decades, the disposal of biodegradable solid waste has become a serious problem to be faced by all countries, due to the increasing scarcity of available land for landfills and increasing distance from generation centers, as well as the substantial increase in total solid waste generated per capita. The accumulation of solid waste in highly populated areas stimulates the dissemination of vectors (rates, cucarachas, flies, virus, bacteria, and parasites) and, consequently spreading of diseases. Regarding the solid waste generated in islands and isolated communities, decentralized strategies for treatment of organic fraction, reducing transportation and impacts related to that is very convenient. This study had the following main objectives: to test the same reactor for decentralized composting during the Swedish summer using organic waste from restaurants at the coast, in Kalmar, Sweden, and under Brazilian conditions, using organic waste from the kitchen of the municipal primary school at Abraão, Ilha Grande, RJ; to evaluate and propose mechanical and operational changes in the reactor for process optimization; to assess the quality and degree of maturation of the compost at different stages of composting through two respirometry methods, the Specific Oxygen Uptake Rate (SOUR) and the ABNT norm NBR 14283. In short, it was concluded that the solid waste composition and initial pH of the material used as amendment are important factors to determine the time required for degradation of the organic acids produced and subsequent pH increase; depending on the organic waste characteristics, it is necessary to use material for augmentation (ex: compost) to improve the development of microorganisms and consequently, optimization of the process; the physic-chemical and microbiological analyses confirmed that the aerobic degradation occurred inside the reactor and that the quality of the produced compost is satisfactory; however, considerable improvements in the shredding and feeding system is required in order to test the reactor s performance in its full-capacity. The respirometric tests carried out using the specific oxygen uptake ra(SOUR) method and the NBR 14283 norm, were effective in indicating the maturity of the compost and the degree of progress in the composting process. Once the mechanical problems in the shredding and feeding system are solved, the reactor might be useful as an innovative technology for treatment of organic waste in situ for small and medium generators.