Two-stage hydrogen and methane production by the treatment of soybean processing waste (molasses and okara) in thermophilic and mesophilic condition

• Grant number: 22/01425-4
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• Effective date (Start): August 01, 2022
• Effective date (End): May 31, 2026
• Field of knowledge: Engineering - Sanitary Engineering - Water Supply and Wastewater Treatment
• Principal Investigator: José Alberto Domingues Rodrigues
• Grantee: Isabela Mehi Gaspari Augusto
• Host Institution: Escola de Engenharia Mauá (EEM). Instituto Mauá de Tecnologia. São Caetano do Sul , SP, Brazil
• Associated research grant: 15/06246-7 - Biorefinery concept applied to biological wastewater treatment plants: environmental pollution control coupled with material and energy recovery, AP.TEM

Abstract

The use of agro-industrial residues for biogas and biomolecules production through anaerobic digestion has gained prominence in the last year due to researchers focusing on the circular economy. Soybean molasses and okara, residues from soybean processing, are candidates for this process, as they have low added value and high production volume. From this perspective, this project evaluates the Anaerobic Sequencing Fed-Batch Biofilm Reactor (AnSBBR) with liquid phase recirculation for bioenergy (hydrogen and methane) production from soybean processing byproducts (molasses and okara) under thermophilic and mesophilic conditions by two-stage anaerobic digestion. This project is related to the thematic project entitled "Application of the biorefinery concept to biological wastewater treatment plants: the control of environmental pollution allied to the recovery of matter and energy" (FAPESP Process nº 2015/06246-7). The main project contribution is the study of soybean molasses and okara fermentation and subsequent digestion of the acidified effluent. The applied volumetric organic loading rate and co-processing with okara influence on performance parameters (productivity and biohydrogen yield), process stability, and reactor efficiency were analyzed. Simplified kinetic analysis of the metabolic pathways, thermodynamic analysis of the biochemical reactions, and microbiological examinations using molecular biology techniques were performed for full comprehension of the anaerobic digestion process. Furthermore, production estimates (hydrogen and methane) on a full scale and the simplified financial analysis comparing two-stage (project target) and single-stage scenarios. (AU)