A membrane coupled to a sequencing batch reactor for water reuse and removal of coliform bacteria

Wastewater reclamation was studied by using a small biological reactor and an external filtration membrane coupled in series. Use of the membrane enhanced the quality of the effluent of the biological reactor in terms of suspended solids and presence of indicator bacteria. Partial removal of faecal coliforms and Escherichia coli was observed in the effluent of a sequencing batch reactor (SBR) previous to filtration by the membrane. Use of the membrane ensured full removal of the indicator bacteria in the final permeate. More than 95% of organic matter, suspended solids, and coliform bacteria were successfully removed. The operation and behaviour of internal submerged membranes in two different bioreactors was an additional objective. For this reason, two configurations-a membrane coupled to a SBR (MSBR) and a continuous membrane bioreactor (MBR)-were used during the study. Particular attention was focused on fouling and hydraulic conditions in the membranes. Fouling could be reduced by maintaining turbulent conditions and by operating at sub-critical flux.