Contribuição para o estudo e avaliação da relação carbono/nitrogênio na compostagem.

Abstract

This research was carried out at the Laboratory of Sanitary and Environmental Engineering (LESA) of the Universidade Federal de Vicosa - MG through the interchange between the UFV and the Universidade Federal da Paraiba - Campus I I . The experimental period happened from March to June of 2001 and was based on the evaluation and comparison of the stabilization degree of solid waste organic fraction, submitted to the composting process under different C/N ratios. With the purpose to vary the C/N ratio, two experiments were made adding sawdust to the solid waste organic fraction in the folio wings proportions: 30 and 15%, and two experiments adding grass to the solid waste organic fraction, in the same proportions. A fifth experiment was made only with the solid waste organic fraction from Coimbra - MG. The experiments were monitored during 90 days through the determination of the physical (temperature and density), chemical (nitrogen, total organic carbon, phosphorus, potassium and humic acids concentrations), physicochemical (moisture content, pH and the volatile and fixed solids) and microbiological (Fecal streptococci) parameters. Through this monitoring process it was possible to evaluate the degree of stabilization for these materials that were submitted to the composting process. It was verified the possibility to add until 30% of sawdust or of grass (in weight) to the solid waste organic fraction without damaging the composting process.The addition of these materials gave same benefits to the process, as the reduction of the composting period, in the experiment with grass and the obtainment of compost without bacteria, in the experiment with sawdust. Besides an efficient process of treatment for solid waste organic fraction, this can also be one solution to regions that produce a lot of sawdust, as well as that one who produce a lot of prune and scrap of grass.