Anaerobic digestion of vinasse in fluidized bed reactors: Process robustness between two-stage thermophilic-thermophilic and thermophilic-mesophilic systems

Author(s)

Ramos, Lucas Rodrigues ^[1] ; Lovato, Giovanna ^{[2, 3]} ; Domingues Rodrigues, Jose Alberto ^[3] ; Silva, Edson Luiz ^[1]

Affiliation

^[1] Fed Univ Sao Carlos DEQ UFSCar, Dept Chem Engn, Rod Washington Luis Km 235, BR-13565905 Sao Carlos, SP - Brazil

^[2] Univ Sao Paulo EESC USP, Sao Carlos Sch Engn, Av Trabalhador Sao Carlense 400, BR-13566590 Sao Carlos, SP - Brazil

^[3] Maua Inst Technol EEM IMT, Maua Sch Engn, Praca Maua 1, BR-13566590 Sao Caetano do Sul, SP - Brazil

• Document type: Journal article
• Source: JOURNAL OF CLEANER PRODUCTION; v. 314, SEP 10 2021.
• Web of Science Citations: 0

Abstract

Two-stage anaerobic digestion (AD) is a solution for the biodegradation of complex wastes, but the best association of temperatures between acidogenesis and methanogenesis is unclear. Our study investigated whether it is best to associate a thermophilic acidogenic reactor with a thermophilic or a mesophilic methanogenic reactor and results were compared to single-stage AD. The effect of increasing the organic loading rate (OLR from 2.7 to 24.7 kg COD/m(3)/d) in thermophilic and mesophilic second-stage methanogenesis of two-stage AD was also assessed. A thermophilic acidogenic reactor (R2-H2-Thermo) treating sugarcane stillage fed thermophilic (R2-CH4Thermo) and mesophilic (R2-CH4-Meso) methanogenic reactors. A single-stage methanogenic thermophilic reactor was used as control (R1-CH4-Thermo). Reactors R2-CH4-Thermo and R2-CH4-Meso showed similar performance at OLR of 2.7-13.3 kg COD/m(3)/d, but the latter achieved the highest methane production rate at 24.7 kg COD/m(3)/d (3.2 L CH4/d/L - 78% higher than R2-CH4-Thermo). The two-stage system (R2-H2-Thermo + R2-CH4-Meso) achieved the best energetic yield: 5.5 kJ/g COD, which was 41% higher than the single-stage system. Operation of a second-stage reactor at mesophilic temperature is the most suitable for vinasse AD due to its flexibility, robustness, and stability of CH4 production, even in situations of organic overload and accumulation of toxic components. Digestate at ambient temperature is also more adequate for fertirrigation. (AU)

• FAPESP's process: 15/06246-7 - Biorefinery concept applied to biological wastewater treatment plants: environmental pollution control coupled with material and energy recovery
• Grantee: Marcelo Zaiat
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 18/17715-6 - Biohydrogen production by treating agro-industry wastes (whey and glycerin) in an AnSBBR operated in thermophilic condition
• Grantee: Giovanna Lovato
• Support Opportunities: Scholarships in Brazil - Post-Doctoral