Compostagem de resíduos agroindustriais através da inoculação de microrganismos eficientes : uma alternativa para a compostagem em pequena escala

Abstract

Waste composting has been growing as an alternative to reduce environmental impacts caused by poor management of waste generated on rural properties. Among the residues, the main one is animal manure. Small properties have difficulty using compost as an alternative to this problem due to the small volume of manure generated. Small-scale composting is a problem, due to its difficulty in maintaining high temperatures and the consequent non-elimination of pathogens, common in animal manure. Due to this, this work had as objective to use the inoculation of effective microorganisms (EM) in small scale composting, in order to eliminate the pathogenic bacteria and to generate a compound rich in nutrients at the end of the process. The internal temperature was measured daily and the analysis of macronutrients, coliforms and Salmonella spp were performed at the beginning and end of the process. The experiment was carried out in the field, using three equal piles, with 0.7 m3 of volume each. Concentrations of EM were placed at the beginning of the composting, 4, 2 and 0 mL/L of water for the 3, 2 and 1 piles respectively, and the no EM addition layer served as control of the experiment. The maximum temperatures reached were 49 °C for pile 1 to 28 days, 50 °C for pile 2 to 25 days and 51 °C for pile 3 to 25 days of composting. The amount of macronutrients increased with the composting process for the three piles studied, the C / N ratios at the end of the process were 11.62:1, 12.33:1 and 11.51:1 for piles 1, 2 and 3 respectively. No initial Salmonella spp was detected and the amounts of coliforms decreased for the three piles, remaining at 14000, 17000 and 400 NMP/g. The use of EM at a concentration of 4 mL/L turned out to be beneficial for small-scale composting of cattle and sheep manure, which caused the compound to reach higher temperatures, keeping them high for a longer period of time and resulting in efficiency in the removal of pathogens and accumulation of N, P and K.