Avaliação da produção de biogás a partir de água residuária de cervejaria

Abstract

The search for alternatives to substitute the demand over fossil fuel nowadays, also for the environmental impact mitigation, are on a worldwide raising, giving a new perspective over the researching field. The composition of the effluents used on a beer production supports the application of fermentative processes on its treatment, making possible the generation of energy compounds (H2 e CH4) through anaerobic digestion, a natural biological process that improves the agglomeration of different kinds of microorganisms, without oxygen, stimulating complex organic compounds’ conversion into simpler compounds. This research’s main goal was to evaluate the efficiency of organic matter removal over indicating the oxygen amount and the biogas production in anaerobic reactors, treating the wastewater of a brewery before and after the acidogenic reactor. The Treatments were made on adapted Schott flasks, for gas and substrate removal, and these flasks were put on shaker in a 37 Celsius degrees temperature. 2 of the 8 Treatments were made on batch process and, the other 6, in different HRTs (6, 12, 24, and 48 hours). The better results in methane and hydrogen production, as in the whole sugar reducer concentration removal, were on the batch process treatments. The whole sugar reducer remotion was the same for both treatments, 1 and 2, and its reactors, getting to 99% of remotion efficiency. Treatment 4 had the best operational condition for the chemical oxygen demand remotion in both reactors, where the post H2 reactor wastewater was used. Which means that the mixed process of H2 and CH4 production allows a higher chemical oxygen demand reduction of some leavings, when compared to an individual process. For the volumetric evaluation, the best operational condition was in A5 reactor (TRH= 24h, 15% inoculum, no buffer) effluent pH 6,01, and affluent pH 3,05, in a 6168 mg L-1 COD and 18,58 g L-1 TRS, organic load applied, leading to 8,7 L d-1 biogas amount, because of sugar high concentration. The best operational condition for methane production was in treatment 2 (B2 reactor), getting 1,41 CH4/d, while the best operational condition for hydrogen production was in treatment 1 (B1 reactor), getting 2,13 L H2/d. As observed in the achieved results, there is a promising biogas production over breweries wastewater, as over its potential usage.