Calcium sulfate (gypsum) scaling remains one of the most persistent challenges in high-recovery reverse osmosis (RO), particularly in sulfate-rich waters typical of mining operations. Conventional RO systems are limited by gypsum solubility, often requiring conservative recoveries and aggressive chemical pretreatment to avoid scale formation—leading to high operational costs and complex brine handling.
Flow Reversal Reverse Osmosis (FR-RO) offers a breakthrough by periodically reversing the direction of concentrate flow through the membrane array. This disrupts the development of localized supersaturation zones and prevents stable crystal growth, allowing the system to operate at higher recovery rates with reduced antiscalant dosing and less frequent cleanings.
This presentation introduces the principles of FR-RO and presents case studies from industrial and pilot-scale deployments treating high-sulfate waters where gypsum scaling was effectively controlled. The scaling conditions in these installations closely mirror those found in mine-impacted waters. The relevance of FR-RO to mining applications—such as water reuse, tailings water treatment, and ZLD integration—will be explored, with emphasis on how this technology enables cost-effective, high-recovery solutions under scaling-prone conditions.
FR-RO represents a promising tool for mining operations seeking to improve water efficiency and reduce the footprint of water treatment systems.