Elucidating Methanogenesis and Membrane Filtration Performance of a Ceramic Anmbr Treating Municipal Waste Leachate

Abstract

An anaerobic ceramic membrane bioreactor has considerable potential for treating low-strength wastewater but needs more study on high-strength waste streams. This study investigated the methanogenesis performance and inorganic fouling behavior of a flat-sheet ceramic AnMBR treating fresh leachate. The performance was elucidated at an average operating flux of 6.2 L/m2·h-1. The system demonstrated over 95% chemical oxygen demand removal efficiency under a hydraulic retention time of 10 days and an organic loading rate of 5.8 kg-COD/m3·d. Different cleaning strategies were then tested under moderate or severe membrane fouling conditions. Physical cleaning can achieve efficient flux recovery after moderate fouling, while citric acid followed by NaClO cleaning was needed when severe membrane fouling occurred. The resistance-in-series distribution showed that pore blocking by inorganic matter dominated the fouling at the end of the experiment, accounting for 48.4% of total resistance, whereby a permeability of 99.7% was recoverable. From the industrial application point of view, a ceramic AnMBR must be evaluated further in large-scale research.

Keywords: anaerobic digestion, ceramic AnMBR, fresh leachate, Membrane fouling, cleaning strategy