Performance Evaluation of Polymeric Tubular Membranes for Wastewater from Rubber Production

The aim of this study was to assess the suitability of polymeric tubular ultrafiltration mem-branes for use in a closed-loop water system within a rubber manufacturing plant. The research focused on determining the transport and separation properties of polymeric tubular mem-branes during the ultrafiltration of wastewater generated from washing vulcanised rubber hoses. The tests were conducted using the installation of the UF-1 membrane supplied by APEKO Sp. z o.o. The study evaluated the performance of modified PES membranes with a molecular weight cut-off (MWCO) of 4 kDa and PVDF membranes with an MWCO of 100 kDa in the wastewater treatment process, as well as the effectiveness of membrane regeneration. Given the characteristics of wastewater, the key parameters for evaluating ultrafiltration performance included the determination of contaminant separation coefficients (R, %) for non-ionic surfactants (NIS) and chemical oxygen demand (COD), as well as turbidity reduc-tion. The results demonstrated that the tested membranes substantially improved the visual quality of the wastewater by reducing turbidity by more than 95%, and exhibited high sepa-ration efficiency for the analysed contaminants, with initial values of RNIS = 95% and RCOD = 85% at the beginning of the ultrafiltration cycle, decreasing to RNIS <  10% and RCOD <  10% after several hours of operation. During closed-loop filtration, when a twentyfold concentration of contaminants in the retentate was reached, membrane fouling occurred, sig-nificantly reducing filtration performance. Chemical cleaning enabled the recovery of ap-proximately 70% of the initial performance for modified PES membranes and full recovery (100%) for PVDF membranes.