Higher Recovery, Lower Costs: Municipal Success Stories with FR-RO Technology
As water scarcity intensifies, municipalities are turning to advanced treatment technologies to maximize local water resources. The webinar, “Squeezing the Last Drop: Using Enhanced-Recovery Reverse Osmosis to Improve Water Production,” showcased how ROTEC’s Flow Reversal Reverse Osmosis (FR-RO) technology is enabling cities like Santa Monica and the Orange County Water District (OCWD) to achieve higher recovery rates, reduce waste, and enhance sustainability in real-world applications.
Orange Country Water District Project
The Orange County Water District (OCWD) is a global leader in water reuse that operates the Groundwater Replenishment System (GWRS), the world’s largest potable reuse facility. To enhance recovery, OCWD piloted ROTEC’s Flow Reversal RO technology, aiming to increase recovery rates and reduce brine waste.
Results:
- Recovery Rates: The FR-RO pilot system evaluated treating primary flow to their existing RO units and treating the concentrate from their existing RO units. The demonstration reached and sustained a consistent recovery rate of 91% showing that a full-scale FR-RO retrofit at OCWD could boost overall recovery while maintaining operational reliability and reducing brine volume by nearly 50%
- Proven Operational Stability: During the pilot, FR-RO maintained stable performance with no membrane degradation, steady flux, and only one CIP every three months. The results supported seamless integration into OCWD’s full-scale system with minimal operational disruption.
- Energy and Cost Effectiveness: The FR-RO system not only demonstrated strong technical performance but also delivered clear advantages in energy and cost metrics. With a specific energy consumption (SEC) of 0.25 kWh/m³, the FR-RO system outperformed the conventional RO system’s 0.29 kWh/m³. This gain in energy efficiency becomes even more significant when considering the increase in water recovery, with more clean water produced using less energy per unit of product. With these results, OCWD compared the costs and found FR-RO to be more cost-effective than CCRO and FO-RO hybrids. The unit cost of additional permeate was lowest with FR-RO, especially at higher recovery levels, supporting the decision to scale up.
Santa Monica Arcadia Treatment Plant Project
The City of Santa Monica aims for water self-sufficiency through its Sustainable Water Master Plan, targeting a diverse, drought-resilient supply and reduced reliance on imported water. A key component is the Arcadia Water Treatment Plant, which piloted and then underwent a retrofit to increase capacity from 10 to 13 million gallons per day (MGD) and enhance RO system recovery to up to 90% with ROTEC’s FR-RO technology.
The City piloted both FR-RO and CCRO technologies in a side-by-side trial to determine the most effective solution for achieving high recovery. FR-RO delivered stronger performance in both recovery rate and system stability, making it the clear choice for full-scale implementation. Based on the pilot results, ROTEC was awarded the contract and successfully completed the retrofit of the Arcadia Water Treatment Plant.
Results:
- Recovery Rates: The FR-RO system consistently achieved a high recovery rate of 91%. This level of performance demonstrated the system’s ability to sustain elevated recovery without compromising stability. In comparison, the existing conventional system can only operate at a maximum recovery of 83%.
- Fewer Membrane Replacement: Over a 144-day pilot period, a comparison was done looking at the membrane replacement of FR-RO vs CCRO. The CCRO system required 5 membrane replacements while FR-RO’s membranes were never replaced showing strong operational stability and low membrane fouling with FR-RO, even under high-recovery conditions.
- Limited Scaling: The FR-RO system maintained efficient scaling control and operated effectively at a pH of 6.3 with just 1 ppm of AWC A-119 antiscalant. Whereas the conventional system typically required a higher antiscalant dose to manage similar fouling risks, highlighting FR-RO’s ability to reduce chemical usage without compromising performance.
The Santa Monica and OCWD case studies validate ROTEC’s FR-RO technology as a scalable, efficient solution for municipal water reuse. By achieving higher recovery rates, reducing operational costs, and enhancing sustainability, FR-RO demonstrates its potential in real-world applications. This approach is already being implemented in other large-scale projects, such as those in Malta and Tuas