The Effect of Mixing Rate on Performance of Anaerobic Reactor in Methane Production

Abstract

In this study, a mathematical model was used to predict the dynamic behaviour of the system under conditions of imperfect mixing in an Anaerobic Digestion (AD) process. To evaluate the system performance, the effect of mixing parameters by calculating the quantities of methane gas produced, system power, and effluent quality was investigated. Numerical results showed that with an increase in the mixing rate ( ) by 20%, methane production rate, power production, and the effluent COD removal efficiency of the system increased by 19%, 19% and 12%, respectively. At an equal mixing rate, the amount of methane produced in influent with a concentration of 12.1% was 4.5 times higher than the influent with a concentration of 2.5%, while no significant change was observed in the effluent quality. Additionally, it was found that the mixing rate effect is more important than the mean cell retention time in the anaerobic reactor. The best fitted correlations for methane production rate and effluent COD removal efficiency using regression analogy at different organic loads of wastewater are presented.

Biogas Production Optimization in the Anaerobic Codigestion Process: A Critical Review on Process Parameters Modeling and Simulation Tools

“…It has been reported that biomethane production increased by 220% with 160 rpm bidirectional mixing [48]. Mixing may be profcient by employing hydraulic (liquid recirculation), mechanical (manually or using a mixer), and pneumatic (recirculation of gases) systems at various frequencies (continuously or intermittently several times in an hour during a day) and strengths (intermittent, gentle, and rotation speed) [49].…”

CFD simulation of the laboratory-scale anaerobic digester to study the impacts of impeller geometric and operational parameters on its performance

“…A proper mixing leads to uniformity of materials and temperature in wastewater and causes the efficient material transfer from substrate to microorganisms in the large volume of the reactor [3]. According to investigations, methane gas production rate and the effluent quality using anaerobic digesters are significantly affected by the mixing [4,5].…”