Ultrafiltration membrane separation for anaerobic wastewater treatment

Abstract

Membrane technology has attracted a lot of attention from scientists and engineers in recent years as a new separation process. Various membrane technologies such as reverse osmosis (RO), ultrafiltration (UF) and microfiltration (MF) have been successfully used for a variety of water and wastewater treatment applications. In this study UF membranes of 10 000 nominal molecular weight limit were used in conjunction with an anaerobic reactor to treat wastewater from a brewery. The UF membranes serve to retain active biomass in the reactor, which is essential for a good reactor performance and for the production of a clear final effluent. The reactor was operated over a range of hydraulic retention times and organic loading rates (OLR) in order to evaluate its treatment efficiency. Six steady states were attained over a range of mixed liquor suspended solids (31 000-38 000 mg 1−1). The maximum organic loading rate applied was 19.7 kg COD m−3 d−1 resulting in a methane yield of 0.27 1 CH4 g−1 COD. The percentages of COD removal achieved were above 96%. The results indicated that the UF membranes were capable of efficient biomass-effluent separation thus preventing any biomass loss from the reactor and have potential for treating industrial wastewaters.