Industrial water reclamation using polymeric membranes - case studies involving a car manufacturer and a beverage producer

This study presents the evaluation of different polymeric membranes for the reclamation of wastewater generated by two manufacturers. Specifically, ultrafiltration (UF) membranes were evaluated for wastewater pretreatment use while nanofiltration (NF) and reverse osmosis (RO) membranes were evaluated for wastewater reclamation use. Results show that both the UF membranes used were not suitable for pretreatment of the oily wastewater stream due to the presence of suspended cathodic electrodeposition (CED) paint particles. The CED paint particles rapidly deposit on the membrane surface resulting in severe fouling and very low permeate fluxes. With respect to the metals and beverage wastewater streams, the polyvinylidine-difluoride (PVDF) UF membrane was shown to be more suitable for pretreatment than the polyacrylonitrile UF membrane. The PVDF-UF membrane had relatively lower flux decline rates, higher turbidity and higher total organic carbon reduction rates. Meanwhile, the low-pressure RO membrane proved to be suitable for wastewater reclamation of the oily and beverage wastewater streams - showing low flux decline rates, high conductivity and high chemical oxygen demand reduction rates. In terms of reclaiming the metals wastewater stream, the NF membrane proved more suitable than the low-pressure RO membrane. The NF membrane had relatively higher permeate fluxes and metals rejection rates compared to the RO membrane.