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Yes, and nanofiltration (NF) is often called membrane softening. NF membranes will remove double-charged hardness ions (calcium and magnesium) better than the single-charged ions (sodium, potassium, chloride, etc.) from raw water. For certain source waters, NF may effectively replace lime softening or the sodium zeolite, ion exchange softener that uses sodium chloride salt for regeneration. Given the appropriate NF membrane, the finished total dissolved solids (TDS) of hard water can be reduced to 300 mg/L or less, with a resulting calcium carbonate hardness well below 100 mg/L. |
