Direct Potable Reuse (DPR) represents the future of sustainable water supply, but it comes with some of the toughest operational demands in water treatment. Systems are required to produce consistently high-quality water from secondary effluent, operate with minimal waste, and run reliably under variable conditions. Flow Reversal Reverse Osmosis (FR-RO) addresses these needs with a proven design that enhances both performance and operational stability. 

Unlike conventional RO, FR-RO reverses concentrate flow across membrane stages on a fixed cycle. This approach prevents scaling and fouling, delivering stable, high-recovery performance without the need for softening, aggressive chemical use, or complex pre-treatment systems. Integrated into the FR-RO system is ROTEC’s patented Block Rotation technology that periodically rotates membrane positions within the system, evenly distributing the burden of scaling and fouling. This method has been shown to extend membrane life and reduce the frequency of cleanings. 

In DPR applications, FR-RO consistently achieves 90–95% recovery. It significantly reduces brine volumes by 30–60% compared to conventional systems and handles elevated concentrations of hardness (250+ mg/L as CaCO₃), silica (40+ mg/L), and phosphate (6+ mg/L). FR-RO has also been validated in large-scale reuse facilities designed to treat ~40+ MGD, confirming its suitability for full-scale DPR implementation, even under challenging feedwater profiles. 

FR-RO integrates seamlessly with UV-AOP, ceramic pretreatment, and other advanced treatment processes. It supports compliance with leading potable reuse standards, including California Title 22 & 17, TCEQ, AZDEQ, and Florida DEP guidelines, and the U.S. EPA’s draft National Reuse Framework.  

Typical post-treatment permeate from FR-RO systems shows: 

• TDS: Consistently well beneath regulatory thresholds for potable water (<500 mg/L) 

• TOC: <2 mg/L, and often <0.5 mg/L when paired with AOP 

• PFAS: >99% removal  

• LRV: Achieves regulatory credit of 1.5–2.0 log virus removal, with actual performance estimated at up to 6-log, supporting full removal targets in DPR treatment trains. 

With fewer cleanings, lower chemical demand, and proven high recovery, FR-RO offers a robust solution for utilities looking to implement DPR at scale.