Reverse osmosis (RO) is an advanced method of water purification that forces water through a semi-permeable membrane to remove impurities. While the membrane filter is central to the RO process, specialized chemicals are also utilized to optimize treatment efficiency.
Pre-Treatment Chemicals
Before forcing water through the RO membrane, pre-treatment chemicals ready the water and extend the life of downstream filters.
- Scale inhibitors - Polyphosphates prevent limescale from hard water that can clog membranes.
- Surfactants - Lower surface tension helping bubbles form around particles so they are easier to remove.
- Coagulants Flocculants - Destabilize particle charges so they clump together for filtration. Common ones are aluminum sulfate and ferric chloride.
- Oxidizing biocides - Chlorine-based disinfectants kill bacteria that can foul membranes.
- Acids - Sulfuric or hydrochloric acid lower pH and remove carbonate hardness.
Membrane Protection Chemicals
The RO membrane itself requires protection against chemical damage.
- Neutralizers - Caustic soda or calcite neutralize low pH water to prevent membrane corrosion.
- Antiscalants - Prevent membrane fouling by inhibiting scale formation from sulfates and carbonates.
- Cleaners - Specially formulated membrane cleaners remove mineral or biological deposits while maintaining integrity of the membrane.
Stabilizing Post-Treatment Chemicals
After water passes the RO membrane, stabilizing chemicals preserve water purity.
- Corrosion inhibitors - Compounds such as phosphates protect pipes from corrosion damage.
- Disinfectants - Chlorine continues protecting against microbes in pipes and storage tanks.
- pH buffers - Carbonates or phosphates stabilize pH at optimal levels.
- Fluoride - Added to adjust fluoride levels for dental health.
Monitoring Chemical Levels
Chemical dosages and concentrations need continual monitoring to maintain proper water treatment. Automated chemical controllers with digital sensors help keep chemical injection rates and residual levels optimized.
While the RO membrane provides the core contaminant removal, proper chemical integration improves membrane lifespan, pre-filters turbid water, enhances the purification process, and stabilizes the treated water. Including qualified chemical treatment experts is key for RO systems operating safely and efficiently.
