Strategies to anaerobic co-digestion of animal manure and lignocellulosic residues in a solid-state leach bed reactor with a focus in circular economic of agro-industrial sector

Abstract

The use of Leached Bed Reactors (LBR) is an advantageous alternative to the anaerobic co-digestion of agricultural residues with high concentration of solids. This type of reactor can be a key part of the transition from a linear to a circular economy in the agro-industrial sector, through the recovery of energy from waste. However, there are still few studies that address the treatment of agro-industrial waste in LBR with a focus on the production of combustible gases. Most of these studies were carried out in Europe, few in North America and Asia, but none in South America. In addition, high solids anaerobic digestion has a disadvantage, the limitation in mass transfers which can result in lower biogas yields. This disadvantage can be partially compensated with alkaline or enzymatic pretreatments of the raw material, aiming to increase the accessibility to its biodegradable compounds. Thus, considering the high generation of lignocellulosic residues and animal manure in the Brazilian agricultural sector, the objective of this internship research project is to evaluate different combinations of alkaline pretreatments and enzymatic pretreatment and anaerobic co-digestion of bovine manure and straw in LBR. The different scenarios will be evaluated in terms of efficiency in waste treatment, methane production, energy balance and economic viability, to establish future perspectives for the use of LBR in the anaerobic co-digestion of animal manure and lignocellulosic residues in Brazil. Being fundamental for this, the obtaining of the technological knowledge of the process in the National Institute of Research for Agriculture, food and Environment (INRAE) of France. It is estimated that the time for the development of this research is 12 months, making it possible at its end to disseminate the knowledge acquired INRAE-LBE to the research group of the Laboratory of Biological Processes of the University of São Paulo. (AU)