Comparison
Single-Pass vs Twin-Pass RO: Which Configuration for Your Plant?
The RO architecture decision is driven entirely by your feedwater TDS. Here is the clean threshold-based answer.
| Specification | Single-Pass RO | Twin-Pass RO |
|---|---|---|
| Feedwater TDS range | < 1,200 ppm | 1,200 – 2,500 ppm |
| Output TDS | 20–80 ppm (variable) | < 30 ppm (consistent) |
| Recovery | 60–75% | 70–85% |
| Capex (same LPH) | Baseline | +45–60% |
| Membrane life | 24–30 months | 24–36 months |
| Power consumption | Baseline | +30–40% |
| BIS compliance reliability | Marginal on hard water | Consistent across feed variations |
Our verdict
For Indian beverage plants in Delhi NCR, Rajasthan, parts of UP and Punjab, twin-pass is mandatory for BIS compliance. For lower-TDS regions (Uttarakhand, HP, NE India), single-pass is sufficient and more capex-efficient.
Frequently asked
Do I need EDI on top of twin-pass RO?+
Only for sub-5 µS/cm output (pharma, semiconductor, ultra-low-TDS specialty water). For BIS packaged drinking water (50-250 ppm), twin-pass is plenty.
Still deciding?
Talk to one of our engineers and we will match the right configuration to your business.
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