A comparative study on the use of membrane bioreactor (MBR) and activated sludge followed by ultrafiltration (CAS/UF) processes for advanced treatment of industrial wastewater

With increasing industrial wastewater reuse, due to inadequate water resources, membrane technology has shown results of very high efficiency in a wide range of reuse purposes and reverse osmosis (RO) pre-treatment. In the present study, the performance of two pilot-scale CAS/UF and MBR to polished effluent wastewater of an industrial town treatment plant were evaluated and compared in a continuous 43-day period. According to the test results, the removal efficiency of total suspended solids (TSS) for both reactors was nearly 100%. Nevertheless, the MBR improved the Chemical oxygen demand (COD) and the total dissolved solids (TDS) by nearly 3% and 5%, respectively. Total nitrogen (TN) and total phosphorus (TP) removals of approximately 31% and 20% in The MBR-based process and 24% and 18% in the CAS/UF module were obtained. Analysis of heavy metal concentration indicated that Cr, Pb, and Ni, which were in both soluble and particle forms, could be adequately eliminated by each system, while Cu, which was mainly in a soluble form, had a lower removal rate (32% and 51% in CAS/UF and MBR, respectively). Besides, since the silt density index (SDI) value for most of the samples was less than 3, both reactors can be used as RO pre-treatment systems.