RO Antiscalant (Phosphonate / Polymeric)
Proprietary blend · 2–6 mg/L
Phosphonate/polymeric threshold inhibitor that prevents CaCO3, CaSO4, BaSO4 and silica scaling on RO/NF membranes. Dosed at the high-pressure pump inlet to hold LSI in range — maintains flux, extends membrane life, and cuts CIP frequency.
Specifications
| Chemical Formula | Proprietary phosphonate / polymeric blends |
|---|---|
| Primary Function | Prevents CaCO3, CaSO4 & silica scaling on membranes |
| Physical Form | Liquid concentrate |
| Application Point | Pre-RO high-pressure pump inlet |
| Typical Dosage | 2–6 mg/L |
| Packaging | 20 kg / 200 kg drums |
Where it's used
- RO / NF Systems
- ZLD Pre-treatment
- High-Recovery Trains
- Sea & Brackish Water RO
- Scale & Silica Control
Related solutions
What it is and when to use it
RO antiscalant is a phosphonate/polymeric threshold inhibitor that prevents scale from forming on RO and NF membranes. Dosed at low concentration before the high-pressure pump, it keeps calcium carbonate, calcium sulphate, barium sulphate and silica in solution as they concentrate, protecting flux and reducing cleaning frequency.
As RO removes water, dissolved salts in the reject stream become more concentrated. At high recovery, sparingly soluble salts exceed their solubility limits and would crystallise on the tail-end membranes. An antiscalant interferes with crystal nucleation and growth, allowing the system to run at higher recovery without scaling.
The right product and dose depend on your feed water analysis, recovery and temperature. They are normally set using membrane projection or antiscalant dosing software, then verified by monitoring normalised flow and pressure drop. The typical dosage is 2–6 mg/L. It is supplied as a liquid concentrate in 20 kg or 200 kg drums. Check compatibility with any upstream cationic coagulant or polymer carryover.
Use it for
- Brackish and seawater RO and NF systems
- High-recovery RO trains and ZLD pre-treatment
- Feeds with high hardness, sulphate, barium or silica
- Any RO plant where scaling limits recovery
How to choose
- Provide a full feed water analysis, including hardness, alkalinity, sulphate, barium, strontium, silica and iron
- Set the dose from a projection at your design recovery and temperature
- Dose continuously, upstream of the cartridge filter or at the high-pressure pump inlet as designed
- Confirm compatibility with upstream coagulants, polymers and chlorine removal chemicals
- Monitor normalised permeate flow and stage pressure drop to detect early scaling
Frequently asked questions
What does an RO antiscalant do?
An antiscalant is a threshold inhibitor. At a few mg/L, it prevents sparingly soluble salts such as calcium carbonate, calcium sulphate, barium sulphate and silica from crystallising on membranes as they concentrate in the reject stream. This maintains flux, protects the tail-end elements and lets the plant run at higher recovery.
How is the antiscalant dose determined?
The dose depends on feed water chemistry, recovery and temperature. It is calculated from a full water analysis using projection software, typically falling within the 2–6 mg/L range, then verified on the plant by trending normalised flow and pressure drop. Under-dosing risks scaling, and over-dosing wastes chemical.
Is an antiscalant needed if I use a water softener?
Softening removes calcium and magnesium, which reduces carbonate and sulphate scaling risk, but it does not address silica or barium, and softener leakage can still cause scaling at high recovery. Many plants use an antiscalant as well. Your water analysis and projection will show whether it is needed.
Technically reviewed by Prashant Dwivedi, Co-Founder & Director ·