Improved bubbling for membrane fouling control in filtration of palm oil mill effluent anaerobic digester sludge

Abstract

Application of anaerobic membrane bioreactor is strictly limited by the membrane fouling because of the fouling prone nature of the feed. This study evaluates a method to enhance the effectiveness of a bubbling system for fouling control in filtration of anaerobic digestion sludge treating palm oil mill effluent using a tilted panel system. Such system is expected to enhance the role of biogas recirculation as the bubbling fluid for membrane fouling control. Effect of tilting angle, bubbling rate, intermittent bubbling period, and panel switching period was investigated. The energy consumption for applying such system was also estimated. Results show that the tilted panel with bubbling remarkably enhance permeability by more than double of the vertical system to reach a maximum value of 87 Lm−2h−1bar−1, the highest value reported so far. The panel switching mechanism helps to enhance the system throughput by allowing two-sided membrane panel with intermittently bubbling, in the expense of mechanical switching energy. The estimation of energy consumption of the system has been estimated at 0.247 kWhm−3, corresponding to 0.3 % of total electricity generated from anaerobic treatment of POME, very attractive for full-scale implementation.