A NOVEL 16-INCH REVERSE OSMOSIS SYSTEM FOR WATER RECLAMATION

This study focuses on the performance of a novel pilot RO system that incorporates 16-inch RO membrane elements at a local water reclamation plant over a period of 8,500 hours. The unique features of the RO system also include innovative patented flow distributors for even distribution of feed water at entrance and exit of each RO membrane element and electromagnetic field (EMF) coils embedded in the pressure vessels for fouling mitigation. The pilot RO system was run in parallel to the existing full-scale conventional 8-inch RO system, using the same ultrafiltrated secondary effluent from a nearby wastewater treatment plant as the feed water. Computational fluid dynamics (CFD) simulations had shown that higher feed flow rate associated with larger diameter membrane element was more evenly distributed across the face of the leading element in the 16-inch RO system with patented inlet flow distributor, compared to the flow distribution in the 8-inch full-scale RO system with standard anti-telescoping device (ATD). The average permeate flux of the 16-inch RO system was about two times higher than that of the full-scale 8-inch RO system. Even at a high permeation rate, fouling was effectively under control in the 16-inch RO system with the feed pressure and salt rejection well maintained throughout the study. The good fouling inhibition was partly attributed to the presence of EMF, which was demonstrated when the permeate flux declined immediately after the EMF was switched off for a period of time in the study. Another benefit of running the 16-inch RO system is the reduction of energy consumption. This study has shown that the 16-inch RO system consumed about 14.8% less energy compared to the 8-inch full-scale RO system