DEGRADATION OF IMPROVED VEGETABLE WASTE WITH BOVINE AND CAPRINE MANURE AND ANALYSIS OF LEACHATE TOXICITY PRODUCED BY VERMICOMPOSTING

Abstract

In Brazil, a half of the fraction of solid urban waste is organic. These wastes, when improperly refused, can form potentially toxic liquids and gases related to big environmental impacts. In this sense, this study aimed to evaluate the vermicomposting process of materials such as pruning residues, leaves and branches in the mixture with bovine and caprine manure. For this purpose, a wooden composter was built, divided into four compartments duly filled with mixtures of similar total masses, varying only the type of manure. To monitor the efficiency of the compost formation process (humus), parameters such as moisture and organic matter (OM) were determined. The phytotoxicity of the leachate produced was also evaluated by analyzing the germination index of Lactuva sativa L. (lettuce), using organic and conventional seeds. After 60 days of monitoring, 17% OM was produced in the mixture with bovine manure, yield 8% higher than caprine, however, more time is needed for the stabilization of the compost. It was verified that the phytotoxic tests with organic seeds presented germination indexes superior to 120%, in 10% of bovine manure and 2.5% of caprine manure, demonstrating stimulus effect, however, the conventional seeds presented opposite results, revealing effect of toxicity.