Estudo e avaliação de um método híbrido de aeração forçada para compostagem em leiras.

Abstract

The Aerate Static Pile Systems - Forced Aeration are constituted as one o£ the most efficient processes, o£ low costs, t o the treatment o£ organic residue (urban garbage, sewer mud, etc.) (SCHULZE, 1981). The modes of aeration in the composting piles are done through air injection ( positive mode) and a ir suction (negative mode), but the positive mode , according to FINSTEIN et alii (1984) is the one that presents more advantages. However, much more can be done yet t o develop the process in relation to the elimination of pathogens and the degradation increasing of the organic material. This work had as its objective to study and evaluate the existent aeration methods and t o propose a hybrid mode ( alternating the positive and the negative modes, in cycles ), which objective-would be the in crea sing of the process efficiency. During the research, seven composting piles were assembled: two, in the positive mode; two, in the negative mode and three in the hy brid mode. The raw material used i n the experiment was a organic fraction of the urban garbage of Belo Horizonte city - MG., triturated, with particles from 20 t o 50 mm, "Zn natafia.". Table 3.1 presents the composition of the utilized garbage. The efficiency- evaluation of each aeration mode was realized thrcugh physical (density, temperature); physicochemical (moisture content, volatilesolids , carbon and pH);chemical (nitrogen) ; and bacteriologic faecal Streptococais analysis besides other diary observations like : aspects, odour, color, attraction of vectores , etc. In the comparison among the aeration modes, was verified that the hybrid mode, developed in this study , presents a betterefficiency . In ali the processes, up to the sixteenth day of the active phase, was registered the presence of pathogenics micro-organisms and on the last day of this phase was not more found the presence of these organisms. In relation to organic material degradation, the hybrid mode piles , presented, in average, a reduction of 35,431 Cin. twenty daysj, revealing the high efficiency of this method'in relation to the others , as i n the positive mode the reduction was of 20,79% (in thirty daysj, and in the negative mode it was of 6,02$ [In fifty - seven days). This study executed its objectives , because it developed a system that elation to moisture reduction, organic material degradation , and elimination of pathogens than the other systems used nowadays.