Free engineering calculator

    RO Recovery, Feed & Concentrate Calculator

    Find RO feed flow by dividing permeate output by recovery, and concentrate flow as the difference. Concentrate TDS rises by 1/(1−recovery) — for 75 % recovery, reject water is 4× the feed TDS.

    Parameters & Duty InputsInteractive

    RO plant

    [m³/h]
    [%]

    20–95 %

    [ppm]
    Live Calculation EngineActive Live Sync

    Awaiting Valid Duty Parameters

    Adjust the parameters on the left to compute live hydraulic values, ranges, and sizing verdicts.

    On-Site & Workshop Support

    Designing or de-bottlenecking an RO plant?

    We size the feed and booster pumps for RO duty and repair existing sets — recovery math first, pumps second.

    RO recovery explained

    1

    The mass balance

    Recovery is the share of feed that becomes permeate. Feed flow = permeate ÷ recovery: at 75 % recovery, 10 m³/h of permeate needs 13.33 m³/h of feed and produces 3.33 m³/h of concentrate. Every plant design starts with this triangle, because it fixes the feed pump, the booster, the membrane train and the reject handling.

    The calculator returns all three numbers from your permeate target and recovery.

    2

    Concentrate TDS and scale risk

    The salts rejected by the membrane stay in the concentrate: concentrate TDS = feed TDS ÷ (1 − recovery). At 75 % recovery a 1000 ppm feed produces 4000 ppm reject; at 90 % it reaches 10,000 ppm — where scaling becomes the dominant design constraint and antiscalant dosing is mandatory.

    The calculator warns above 85 % recovery, and the dosing calculator sizes the antiscalant feed.

    3

    From balance to pumps

    The feed flow feeds the booster sizing: RO membranes need 5–15 bar (brackish) and the booster supplies the differential above the incoming pressure. Teflow supplies and repairs RO booster and feed pumps across Gujarat — call +91 98251 62709 with your permeate target for a pump recommendation.

    Frequently Asked Questions

    Technical & Operational FAQs

    Q1.What is RO recovery?

    The percentage of feed water that becomes permeate. Recovery = permeate ÷ feed × 100. Typical brackish designs run 65–80 %; higher recovery concentrates salts faster and risks scaling.

    Q2.How do I calculate feed flow?

    Feed = permeate ÷ recovery (as a fraction). For 10 m³/h permeate at 75 % recovery: 10 ÷ 0.75 = 13.33 m³/h feed, with 3.33 m³/h concentrate. The calculator does this instantly.

    Q3.Why is concentrate TDS higher?

    The membrane rejects salts into a smaller flow: concentrate TDS = feed TDS ÷ (1 − recovery). At 75 % recovery, salts concentrate 4×; at 90 %, 10×. This drives antiscalant needs and discharge compliance.

    Q4.What recovery should my RO run at?

    Typically 65–80 % for brackish water, lower for high-TDS or scaling feeds. Above ~85 %, scale risk and concentrate handling dominate — use antiscalant and monitor Langelier index. The calculator flags the risk zone.

    Q5.What pump do I need for my RO?

    A feed pump delivering the feed flow at the membrane feed pressure, plus a booster for the differential. Enter the feed flow here, then size with the booster calculator. Teflow supplies both for RO duty.

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    Need a custom hydraulic audit or specific duty curve verification? Call +91 98251 62709 or Request a Detailed Engineering Quote.