Chloride Reduction & Removal in Residential ApplicationsBy: Michael Urbans
Strong Base Anion resins in the chloride form will not remove or reduce chlorides. Why? The resin exchanges chloride for alkalinity and contaminants (nitrate, TOC, etc.). Details are as follows:
- Strong Base Anion resin used in the home is regenerated with NaCl (salt).
- As water passes through any anion resin in the chloride form it is exchanging chloride for anions which have a greater affinity for the SBA – nitrate, sulfate, etc.
- When the resin is exhausted it is regenerated with NaCl. The anion resin is overwhelmed by the high concentration of chlorides and the nitrates, sulfates etc. are exchanged off as the chloride goes back on the SBA exchange sites.
- If you have 450 ppm of chloride coming in, it’s going to increase to a much higher level, equivalent to the amount of sulfate, nitrate anions that you take out of the water. This same problem will occur if you are trying to reduce sulfates – SO4.
- Adding sodium carbonate to the brine tanks may reduce chloride but it’s not a real strong science so it’s not recommended.
- Membrane technology – Reverse Osmosis is the only practical way to reduce chlorides in residential applications.
- Demineralization: A strong acid cation (SAC) in hydrogen (H) form followed by a strong base anion (SBA) resin in hydroxide (OH) form following will remove all ions including chloride but acid and caustic will be necessary for regeneration. This is not practical for home use.
- Mixed bed resin: A mixed bed composed of SBA in hydroxide form and SAC in H form will also remove all ions including chlorides however, as with demineralization it is not practical for home use.