Insights of energy potential in thermophilic sugarcane vinasse and molasses treatment: does two-stage codigestion enhance operational performance?

Author(s)

Ribeiro, Alexandre Rodrigues ; Devens, Kauanna Uyara ; Camargo, Franciele Pereira ; Sakamoto, Isabel Kimiko ; Varesche, Maria Bernadete Amancio ; Silva, Edson Luiz

• Document type: Journal article
• Source: BIODEGRADATION; v. 36, n. 1, p. 20-pg., 2025-02-01.

Abstract

The study evaluated the performance of thermophilic co-digestion in both single-stage methanogenic reactors (TMR) and two-stage systems, consisting of a thermophilic acidogenic reactor and a thermophilic sequential methanogenic reactor (TSMR). A 1:1 mixture of sugarcane vinasse and molasses was codigested in anaerobic fluidized bed reactors, with varying organic matter concentrations based on chemical oxygen demand (COD) ranging from 5 to 22.5 g COD L-1. Both systems achieved high organic matter removal efficiency (51 to 86.5%) and similar methane (CH4) yields (> 148 mL CH4 g(-1)COD(removed)). However, at the highest substrate concentration (22.5 g COD L-1), the TSMR outperformed the TMR in terms of energy generation potential (205.6 kJ d(-1) vs. 125 kJ d(-1)). Phase separation in the two-stage system increased bioenergy generation by up to 43.5% at lower substrate concentrations (7.5 g COD L-1), with hydrogen (H2) generation playing a critical role in this enhancement. Additionally, the two-stage system produced value-added products, including ethanol (2.3 g L-1), volatile organic acids (3.2 g lactate L-1), and H-2 (0.6-2.7 L H-2 L-1 d(-1)). Microbial analysis revealed that Thermoanaerobacterium, Caldanaerobius, and Clostridium were dominant at 5 g COD L-1, while Lactobacillus prevailed at concentrations of >= 15 g COD L-1. The primary methane producers in the single-stage system were Methanosarcina, Methanoculleus, and Methanobacterium, whereas Methanothermobacter, Bathyarchaeia, and Methanosarcina dominated in the two-stage system. (AU)

• FAPESP's process: 22/10615-1 - Consolidation of the biorefinery concept applied to the biological treatment of wastewater and solid wastes
• Grantee: Marcelo Zaiat
• Support Opportunities: Research Projects - Thematic Grants