Processo de compostagem em pequena escala, com aquecimento solar e adição de micro-organismos eficientes

Abstract

An alternative for the treatment of organic waste is composting, which is a controlled aerobic microbial decomposition process conducted under conditions in which the decomposing microorganisms to develop. The objective was to evaluate the composting process on a small scale using solar heating system and adding efficient micro-organisms. Thereby, composting boxes were mounted using restaurant residue and tree pruning, applying 4 treatments: with heating and efficient Micro-organisms (EMs) (CC), with heating and without EMs (CS), without heating or EMs (SS) and without heating and with EMs (SC). Was performed physicochemical and microbiological monitoring for 42 days of composting. The evaluated physical-chemical parameters were: temperature, pH, ratio Carbon/Nitrogen (C/N), volatile solids, electrical conductivity and humidity. Microbiological monitoring were quantified by standard counting method plate, the heterotrophic bacteria and EMs: yeasts, actinomycetes, fungi and bacteria fermenters lactose. In relation to analyzed microorganisms, all treatments showed similar behavior over the composting process. At the end of 42 days the number of heterotrophic bacteria, actinomycetes, filamentous fungi, yeasts and bacteria fermenters lactose were on the order of 108, 108 a 109, 105 a 106, 107 a 108 e 104 a 105, respectively. All treatments reached the thermophilic stage with the highest temperature collected from 49,7°C, 49,0°C, 48,2°C and 47,7°C, respectively for the treatment SS, CC, CS and CS. The pH of all treatments at the end of the composting process was close to 7,5. The initial ratio of C/N of the treatments was approximately 10/1 and reduction treatments at the SS, CC, CS and CS were, respectively, 20,2%, 1,0%, 1,0% and 9,8%. The weight reduction after 42 days of composting ranged 67-76%, and the volume reduced in all treatments was about 60%. The electrical conductivity showed an increase of 218%, 309%, 254% and 290% in treatments SS, CC, CS and SC, respectively compared to the initial value. The humidity in the treatments was presented within the range 50-60%, which is within the limits desirable for this parameter. The reduction in volatile solids over the composting process was in the range of 5,0% in all treatments. For data analysis, it was found that the heating system and the EMs made no difference in the composting process to the four treatments.