Produção de hidrogênio a partir da co-digestão de resíduos de indústrias de processamento de leite e frutas.

Abstract

The co-digestion of waste from milk and fruit processing industries for hydrogen production from anaerobic fermentation at mesophilic temperature was first investigated in this paper. The hydrogen-producing bacteria derived from an upflow anaerobic sludge blanket reactor (UASB) from a household wastewater treatment plant (WTP) were used to produce hydrogen from a wastewater solution from milk and fruit processing industries, through a factorial experimental design according to the methodology of the Central Composite Rotatable Design (CCRD). Inoculum heat pretreatment associated with pH control was applied to select hydrogen producing bacteria and endospore-forming bacteria. The assays were performed in eleven batch reactors to verify the efficiency of carbohydrate and protein conversion in H2 by the hydrogen producing bacteria. Given the studied reactors, the R8 reactor with substrate composed of 100% fruit processing industry effluent and inoculated with 12.5% substrate volume sludge presented the best hydrogen production efficiency, with a specific maximum yield of 0.82 mL H2/gSV for eighteen days of batch operation. Concluding that in case of impossibility of improvement of the experiment, aimed at dilution and inhibition of surfactant compounds present in the residue of the milk processing industry, it is more advantageous to work with the isolated digestion of residues of the fruit processing industry.