Integrating hydrogen and methane production in an AnSBBR: The kinetic model of metabolic pathways and energy estimation

Abstract

The separation of the anaerobic digestion process into two steps has several advantages over the conventional single-stage process, it allows the selection of different microorganisms in each reactor and enables the increase of energy recovery. In the acidogenic stage, biohydrogen and other metabolites of interest (such as ethanol and organic acids) can be obtained, and in the methanogenic phase, biomethane and environmental adequacy of the wastewater can be obtained. However, for full-scale implementation of projects, further insight is needed into the various aspects of this new technology. This work aims to compare AnSBBR that used pure substrates for hydrogen and/or methane production and AnSBBR that used effluent from hydrogen production to produce methane. Biokinetic modeling was used to understand the metabolic pathways of the reactors. It was possible to infer that in the one stage system the methane production originates mainly from the acetoclastic route and in the two stage system from both acetoclastic and hydrogenotrophic routes. The energy estimation of the investigated systems was carried out and the twostage bioenergy system treating sucrose-based wastewater was able to produces 21.1 kJ per gram of removed COD. © 2017 by Nova Science Publishers, Inc.