Treatment of primary settled municipal wastewater in a pilot scale MBR

Abstract

Abstract Membrane bioreactors (MBRs) technology shows many advantages that convert it into an attractive solution for upgrading existent wastewater treatment plants (WWTP). The aim of this study was to investigate the feasibility of applying an MBR for treating primary settled wastewater in large WWTPs. In the 400,000 inhabitants equivalent WWTP of Vigo (NW Spain), 174,000 m3 d−1 of wastewater receives primary treatment, whereas only 130,000 m3 d−1 receives secondary treatment. In this facility, land scarcity is an issue, thus, the conventional activated sludge system (CAS) used may be replaced by MBR to retrofit this WWTP. This study was carried out in an MBR pilot plant of 3.97 m3 effective volume using a modified University of Cape Town (UCT) process with a Zenon ZW500d membrane module operating at low HRT (4–7 h). During the experimental stage, permeability values ranged from 90 to 125 l h−1 m−2 bar−1, with fluxes between 20–23 l m−2 h−1. Only three maintenance cleanings were applied during the 286 ex...