RO Recovery Calculator
Calculate permeate flow, reject flow, TDS, and concentration factor for single or double-pass reverse osmosis systems. Essential for ZLD plant design and water reuse projects.
Free · Single & Double Pass · TDS Mass BalanceRO System Parameters
Calculate permeate, reject, TDS, and concentration factor for single or double-pass RO systems.
Typical: 65–75% (single pass)
Standard membranes: 97–99%
How to Use This Calculator
- 1Enter the feed flow (KLD) and feed TDS (mg/L) — from your raw water or pre-treated effluent analysis.
- 2Set the recovery % — typically 65–75% for single pass. Enter your membrane's salt rejection % (usually 97–99%).
- 3Choose single or double pass. Double pass produces ultra-pure water (permeate of pass 1 feeds into pass 2).
RO Design Formulas
Permeate flow (KLD) = Feed × Recovery ÷ 100
Reject flow (KLD) = Feed − Permeate
Concentration factor (CF) = 1 ÷ (1 − Recovery ÷ 100)
Reject TDS (mg/L) = Feed TDS × CF
Permeate TDS (mg/L) = Feed TDS × (1 − Salt Rejection ÷ 100)
ZLD & Water Reuse in India
The Central Pollution Control Board (CPCB) has mandated Zero Liquid Discharge (ZLD)for water-intensive industries including textile dyeing and finishing, tanneries, sugar, distilleries, and certain pharmaceutical facilities located in critically polluted areas of India.
A typical ZLD system uses: primary treatment → biological treatment → ultra-filtration (UF) → reverse osmosis (RO) → evaporation/crystallisation. The RO system recovers 70–80% as reusable permeate while concentrating the reject for final evaporation.
Designing a ZLD or RO System?
Spans Envirotech designs and commissions ZLD systems, UF/RO plants, and water reuse solutions for textile, pharma, food, and industrial sectors across India.