RO Recovery (%)

RO Recovery is the ratio of permeate (purified water output) to feed water input, expressed as a percentage. The remainder is **RO reject** (concentrated salt water, also called "brine"), which must be discharged or recovered. Typical recovery ranges: - **Single-pass RO** on low-TDS feed: 70-80% - **Single-pass RO** on high-TDS feed: 60-70% - **Twin-pass RO**: 75-85% (better permeate quality, similar overall recovery) - **High-recovery RO + RO reject recovery**: 85-95% (with capex penalty) Higher recovery means less reject water (lower discharge cost, important in ZLD-mandated states). But higher recovery also means more concentration on the membranes, accelerating fouling and shortening membrane life. Most Indian states now require **30%+ reject recovery or ZLD** (Zero Liquid Discharge) for new beverage plants, especially in water-stressed districts.