Ultrafiltration for purification and treatment of water streams in swimming pool circuits

The paper presents possible applications of pressure-driven membrane processes for treatment of swimming pool water and purification of waste streams - washings. Newly identified swimming pool water quality issues are presented that require a modernization of existing technologies. The studies used polymer membranes with the same particle distribution range (50000 Da), but made of different membrane-forming materials: polyvinylidene difluoride (PVDF) and polyether sulfone (PES) for purification of washings. The ultrafiltration process allowed obtaining a high turbidity reduction rate in washings (over 95%), and also a significant reduction of total organic carbon. The effectiveness of the PES membrane was reduced after the process commencement, whereas the separation capacity of the PVDF membrane increased during the studied filtration process. While setting the operational process parameters consideration should be given also to the resistance of used membranes to chlorine present in the swimming pool water. A prolonged exposure of the polyether sulfone membrane to chloride may have caused its gradual damage and degradation of its separation properties.