Enhancement of Anaerobic Treatment Efficiency through Process Modification

Three different series of anaerobic filters were compared for operational stability and conversion efficiency under steady (continuous) and transient (pulse) loading conditions. Each of the three series was similar with respect to hydraulic flows, but differences in gas management resulted in correspondingly unique levels of biological hydrogen removal and gas phase washout in each case. Preliminary results demonstrated that the series designed to maximize physical gas phase washout of hydrogen from the early process stages performed better than reactors which depended primarily on biological hydrogen removal. However, the results also demonstrated that biological hydrogen removal can be enhanced by providing longer gas phase retention times, thereby enriching for hydrogen-oxidizing methanogens. Recommendations for further studies to determine whether this latter option can be applied for the advancement of process control in comparison with enhancing physical gas transfer and removal are presented.