A pilot application of recycled discarded RO membranes for low strength gray water reclamation.

Reuse of recycled RO membranes after oxidative treatment as ultrafiltration membranes promise to bring membrane filtration at par with conventional treatment processes in terms of cost-effectiveness. Although the treatment process in which discarded RO membranes are converted into ultrafiltration membranes is well documented, limited pilot data are available for their application in different filtration applications. This research gap is felt because most commercially available RO membranes are spiral, wound while the ultrafiltration membranes commonly used for water filtration applications are hollow fiber. Pilot-scale data will help to develop performance guidelines and predict fouling characteristics of different types of feed waters. In the current paper, converted RO membranes are subjected to filtration with domestic gray water as the feed source. The results show that the converted membranes performed at par with conventional filtration while also providing a consistent filtrate turbidity of < 1 NTU. The reduction in cost and physical footprints and recycling of membranes that would otherwise have ended up in landfills are added advantages that makes this an attractive proposition for gray water filtration applications.