Reciclagem de resíduos orgânicos urbanos e rurais com biocarvão

Abstract

Organic wastes demand appropriate forms of disposal, advances in recycling techniques are fundamental to recovery the nutrients located in the material. Composting is the technique of recycling organic matter by the action of aerobic microorganisms. Pyrolysis is the process of carbonization of biomass, which has biochar as end product, commonly presenting favorable characteristics for use in agricultural crops. Co-composting is the process that integrates both techniques. The objective of this work was to evaluate the process of recycling waste organic matter, using composting and pyrolysis processes from urban and rural residues. In chapter one, the performance of biochars in the composting of the residues was evaluated and, for this, the biomass was charred and conducted to compost, analyzed the number of microorganisms present in the compost piles, determined the total emission of greenhouse gases during the process and the characterization of the products obtained. In chapter two, the toxicity of biochars associated to composting was evaluated and, for this, the tests of germination of sensitive seeds and the behavior of worms were used in relation to the preference for the products. The research was conducted at Embrapa Agrossilvipastoril, Sinop/MT unit and the residues used were corn silage, bovine manure, poultry litter, rice husk and raw vegetable peels. Biochars were produced from the rice husk at temperatures of 400°C and 600°C and from the poultry litter at 400°C and combined with the residues to process by the composting method. There was an increase in pH by adding the biochars into the composts. The higher amount of microorganisms along the composting process, as well as a higher CH4 emission, was identified in the compost without biochar. The compost associated with biochar of rice husk at 600°C and biochar of poultry litter at 400°C showed the lowest total emission of greenhouse gases during the decomposition process, the same materials showed no effect of avoidance for Eisenia fetida worms. The biochars from the rice husk, carbonized at 400°C and 600°C, showed good conditions for germination of radish seeds.