Avaliação de diferentes inóculos na digestão anaeróbia da fração orgânica de resíduos sólidos domésticos

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

The process of anaerobic digestion of organic solid wastes can be optimized and accelerated by using methods that contribute to achieve a rapid and balanced start-up, such as the use of appropriate inocula. In this context, the present study aimed to analyze the potential application of bovine manure, pig manure and bovine rumen as inocula for the anaerobic digestion of the Organic Fraction of Municipal Solid Wastes (OFMSW). The organic fraction used as substrate was prepared in the laboratory according to the method described by Pinto (2000). The bioreactor consisted of a high density polyethylene container with a total volume of five liters, equipped with a biogas measuring system. The reaction media were prepared in duplicate using standard waste, inocula (bovine and pig manure and bovine rumen), water and buffer (sodium bicarbonate). An inoculum factor of 0.2 was employed, and 600 g of Prepared Organic Fraction of Municipal Solid Wastes (POFMSW) were used in each bioreactor, considering that the total solid wastes of the reaction medium would be approximately 20%. A comparison was made of the performance of the different inocula and of the blank (control) reactor, in which the reaction medium consisted only of OFMSW, water and buffer. Throughout the 167-day experiment, all the bioreactors showed intense biogas production, with a mean biogas volume of 1.3 L/day. In terms of total biogas production, the bioreactor inoculated with bovine rumen (144 L) was found to produce the largest volume, followed by the blank reactor (137 L), the reactor inoculated with pig manure (117 L), and lastly the one inoculated with bovine manure (122 L). At the end of the experiment, it was found that the Total Volatile Solids (TVS) degradation rate in the blank reactor was 58%, while that of the bioreactors inoculated with bovine manure, pig manure and bovine rumen showed degradation rates of approximately 25%, 47% and 41%, respectively. The TVS degradation rates indicated that the amount of inoculum employed here was probably insufficient to accelerate the digestion. Possibly, also, the microorganisms of the inocula did not adapt to the OFMSW, since the blank reactor showed a higher degradation rate than the other reactors.

ASSUNTO(S)

inóculos saneamento ambiental fração orgânica de resíduos sólidos urbanos digestão anaeróbia

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