Study on the treatment of corn alcohol wastewater by the internal circulation anaerobic reactor

Abstract

To comprehensively assess the efficacy of employing the internal circulation (IC) anaerobic reactor for corn alcohol wastewater treatment and investigate its feasibility, this study focused on anaerobic digestion parameters, energy balance, and the composition of the prokaryotic microbial community. During the operation of the reactor, the hydraulic retention time was progressively reduced from 4.8 to 1.6 days while achieving an average organic loading rate of 12.46 kg chemical oxygen demand (COD)/(m3·d). Moreover, the removal rate of COD exceeded 98%, and the energy balance (ΔE) reached 10.29 kJ/g fed COD. The initial manifestation of organic acidosis in the reactor was a decline in gas production, which is primarily caused by propionic acid accumulation. The subsequent analysis revealed a high diversity of prokaryotes in granular sludge, with the predominant archaea primarily involved in methane production through the acetic acid pathway. The IC anaerobic reactor shows exceptional performance in treating corn alcohol wastewater by optimizing its operating conditions. Energy balance analysis confirmed the feasibility of the process. The findings of this study may offer valuable insights for optimizing control strategies and engineering applications. HIGHLIGHTS The COD removal rate of the IC reactor exceeded 98%.; The production of biogas can serve as a crucial indicator for rapidly determining the occurrence of organic acidosis.; The implementation of the external circulation of the IC reactor enhanced system stability.; Methanosaeta is emerging as the predominant genus among methanogenic archaea.;

Keywords

• anaerobic digestion
• energy balance
• organic acidosis
• prokaryotic biodiversity