Pre-treatment reverse osmosis water recovery method for brine retentate metals removal

摘要

A pre-treatment method for cleaning and maintaining reverse osmosis membrane filters by injecting sulfurous acid into waters with suspended solids in a liquid fraction to be filtered to form sulfurous acid (H₂SO₃) to acid leach heavy metals into the liquid fraction, reduce alkalinity and mineral scaling, add sufficient SO₂ as a biocide to attack bacteria and other micro organisms to prevent membrane fouling, reduce iron to prevent iron deposit build-up, scavenge and remove dissolved oxygen prior to filtration to prevent membrane oxidation, and then sequentially filtering the acidified water through membrane filters to create a metal free permeate and a brine retentate, which can be pH adjusted to remove the heavy metals as metal hydroxide precipitates.