A Sustainable Approach to Low Pressure Reverse Osmosis

opulation increases within the city of Ormond Beach, Fla., during the late 1990s and early 2000s increased demand on the city’s 8-mgd conventional lime-softening water treatment plant (WTP). The city was faced with expanding the plant, but gradual deterioration of the city’s raw water supplies from saltwater intrusion and upconing made it impractical to increase the plant’s capacity by adding supplemental lime-softening units. To meet increased potable water demands, improve reliability, and continue to provide high-quality potable water from a deteriorating raw water supply, the city decided to expand the WTP with low pressure reverse osmosis (LPRO) membrane technology. Beginning in 2003, the city’s consultant, CDM, conducted a pilot study and completed the preliminary design for a 4-mgd LPRO membrane expansion to supplement the existing 8-mgd lime-softening facility. Several challenges were encountered throughout the project, but the most significant was associated with managing the LPRO concentrate stream.