PROCESSES INTEGRATION OF ADVANCED OXIDATIVE ELECTROCHEMICAL PROCESSES WITH ANAEROBIC BIOLOGICAL PROCESSES FOR THE TREATMENT AND ENERGY RECOVERY OF COMPLEX AGROINDUSTRIAL WASTES

• Grant number: 25/02633-8
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: November 01, 2025
• End date: October 31, 2028
• Field of knowledge: Engineering - Sanitary Engineering - Water Supply and Wastewater Treatment
• Principal Investigator: Marcelo Zaiat
• Grantee: Brenda Clara Gomes Rodrigues
• Host Institution: Escola de Engenharia de São Carlos (EESC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Associated research grant: 22/10615-1 - Consolidation of the biorefinery concept applied to the biological treatment of wastewater and solid wastes, AP.TEM

Abstract

In recent decades, growing global concern about climate change has intensified debates on the management of agro-industrial waste, such as vinasse, soybean molasses, and crude glycerol, with the aim of transforming them into bioenergy. For instance, ethanol production from sugarcane generates significant volumes of vinasse, a residue rich in organic compounds and highly polluting. In Brazil, ethanol production during the 2023/2024 harvest exceeded 35 billion liters, resulting in approximately 408 billion liters of vinasse. Meanwhile, in the soybean production chain, one of the main byproducts is soybean molasses, which accounts for about 30% of the volume generated during the protein concentration process of soybean meal. Rich in complex carbohydrates, such as raffinose and stachyose, soybean molasses requires pre-treatment to release fermentable monomers, enabling its efficient use in bioprocesses as a carbon source. Similarly, crude glycerol, a byproduct of biodiesel production primarily derived from soybean oil, reached an estimated production of 644 thousand m³ in 2023, representing about 10% of the total biodiesel volume produced during that period. However, crude glycerol faces challenges due to its toxicity, low nutrient content, and high purification costs, which limit its large-scale application. These agro-industrial residues hold significant energy potential for biogas production, contributing to a more sustainable energy matrix. Nevertheless, their complex physicochemical characteristics-such as the presence of toxic and recalcitrant compounds, as well as high organic loads-require specific strategies for proper and efficient management. Techniques such as co-digestion and pre-treatment have been widely studied to optimize the anaerobic digestion (AD) process, increasing biogas production and enhancing process stability. Moreover, the combination of advanced oxidative electrochemical processes (AOEPs) as a pre-treatment, followed by AD and co-digestion, has emerged as an integrated and promising approach. AOEPs, in particular, stand out as a complementary and sustainable technology capable of improving the biodegradability of waste and enhancing the efficiency of anaerobic systems. The integration of these technologies aligns with the principles of sustainable waste management and the circular economy, promoting the mitigation of environmental impacts and the energy recovery of agro-industrial byproducts. However, large-scale application still requires further studies to achieve technical and economic optimization, encouraging environmentally responsible and viable solutions. The adoption of these practices would not only reduce dependence on non-renewable energy sources but also contribute to lowering the environmental footprint associated with agro-industrial production.