Anaerobic treatment of agro-industrial wastewaters for COD removal in expanded granular sludge bed bioreactor

• DOI: 10.18331/brj2017.4.4.3
• Publication Date: 2017-11-29T15:43:28Z
• Authors: Abumalé Cruz-Salomón; Edna Ríos-Valdovinos; Francisco Pola-Al...; Rocío Meza-Gordillo; Selene Lagunas-Ri...; Víctor M. Ruíz-Va...
• Keywords: Vinasse; Biogas production; Fuel; Energy industries. Energy policy. Fuel trade; 01 natural sciences; 7. Clean energy; 6. Clean water; 12. Responsible consumption; TP315-360; 13. Climate action; Anaerobic EGSB reactor; HD9502-9502.5; Coffee-processing wastewater; Cheese whey; 0105 earth and related environmental sciences

Untreated agro-industrial wastewaters are undesirable in the aquatic environment due to the presence of high organic matter contents. However, they may constitute a large potential for biogas production. The present investigation is focused on three laboratory-scale anaerobic expanded granular sludge bed (EGSB) bioreactors, continuously operated for 60 d under mesophilic condition with the aim of exploring the feasibility of treating three most significant agro-industrial wastewaters in Chiapas, Mexico (i.e., cheese whey, vinasse, and coffee-processing wastewater). The EGSB bioreactors were operated with a hydraulic retention time (HRT) of 6 d under stable conditions (i.e., buffer index (BI) of 0.31, 0.34, and 0.03), generating a maximum chemical oxygen demand (COD) removal efficiency of 91, 74, and 96% with an average methane production of 340, 245, and 300 mL/g COD∙d for cheese whey, vinasse, and coffee-processing wastewater, respectively. According to the obtained results, the EGSB bioreactors could be a sustainable alternative to simultaneously solve the environmental problems and to produce bioenergy.