Desempenho de processos de compostagem em pequena escala: um estudo comparativo no semiárido Paraibano.

Abstract

It is estimated that around half of the solid wastes generated in Brazil is composed of organic wastes (IBGE, 2010). Since these wastes have the characteristic of biodegradability, the use of composting processes for its treatment becomes very attractive. This study examined the applicability of three types of composting bins and a compost pile for recycling organic solid wastes on a small scale so that to provide a useful alternative to tackle the problem of organic solid wastes and return to the environment a final product in the form of organic fertilizer. The methodology consisted of assessing and monitoring the composting processes for the different types of composters. The monitoring of the mixture of organic wastes was based on the correction of C/N ratio, moisture and oxygenation, and observation of the parameters: temperature, volatile solids, pH, dry matter reduction and electrical conductivity. Comparing the performance of the composting process developed in the pile with those conducted in composting bins, it was observed that the pile proved to be more efficient in most of the monitored parameters. The results also suggest that among the three types of composting bins evaluated, the ones constructed with water bottles stood out, especially for achieving the largest reductions in the parameters volatile solids and dry matter. The produced compounds attended almost all the minimum requirements for commercial purposes, as stated by the Instruction n° 25/2009 of the Ministry of Agriculture, Livestock and Supply, Brazil. Thus, the small-scale composting processes developed in this study were shown to be effective for the treatment of organic wastes and viable for semiarid conditions.