Demineralization
There are two basic categories of demineralization systems: roughing demineralizers and polishing demineralizers. The roughing demineralization stage does a thorough job purifying your raw process water, removing the bulk of mineral contamination and bringing your water quality close to your desired purity. Polishing demineralizers put the final touch on your process water, achieving the exact water quality you need.
Roughing Demineralizers consist of either a Cation/Anion or reverse osmosis (RO) system. Cation /Anion systems use any combination of specialized ion exchange units to achieve the water purity determined by your process requirements. RO systems use membrane technology to provide a continuous process with reduced chemical consumption.
Polishing Demineralizers are specialized systems that are used after the roughing stage to reduce any residual minerals and ionic content. In some applications, such as low-pressure boilers, polishing is not required.
| Chosing A Roughing Demineralizer | Water Quality Produced | Capital Cost | Operating Costs | Waste Stream Produced | Ease Of Operation | Regenerant Chemical Use |
| RO* | Good | High | High | High | More Involved | Low |
| Double Pass RO* | Better | High | High | High | More Involved | Low |
| Co-Current Regen | Good | Medium | High | Medium | Easy | High |
| Split-Flow Counter Current | Better | High | Medium | High | Easy | Medium |
| Counter Current Layered Bed** | Better | Medium | Medium | High | More Involved | Low |
| Packed Bed (Amberpack) | Better | Medium | Low | Low | Easy | Low |
| Sandwich Packed Bed** (Amberpack) | Better | Medium | Low | Low | More Involved | Low |
Typically an RO System is a stand-alone unit, capable of achieving near polished water quality when a double pass system is used. However, in certain cases RO is followed by an ion exchange unit in the roughing or polishing stage to achieve extreme water purity.
Layered beds and sandwich beds (such as Amberpack™) are typically used when the hardness to alkalinity ratios are favorable or when there is high mineral acid content in the water.
| Chosing A Polishing Demineralizer | Feed Water Quality | Water Quality Produced | Capital Cost | Operating Costs | Waste Stream Produced | Ease Of Operation | Regenerant Chemical Use |
| E-Cell* | High | Best | High | High | Low | More Involved | None |
| Mixed-Bed** | High | Best | High | Low | Low | Very Involved | Medium |
| Hi-Flow Cation Polisher*** | High | Best | Low | Low | None | Easy | None |
E-Cell™ produces higher quality water than mixed beds at comparatively lower operating costs with average TDS (Total Dissolved Solids) levels.
When TDS levels are in the very low or very high range, mixed beds offer a better performance to cost ratio than EDI.
Cation polishers primarily remove Sodium ions
