Process for removing arsenic from water
AssigneeTexas Romec, Inc.
InventorsRodney J. O'Connor, Mark A. O'Connor
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Abstract
A process for treating arsenic-containing aqueous waste is described wherein the aqueous waste, treated if necessary to minimize the presence of materials which reduce the efficiency of reverse osmosis membranes, is passed through an ultrafilter to remove solids followed by a chemical treatment to adjust the pH to range from about 6 to 8 and to add antiscalants and antifouling materials, then following to subject the chemically treated filtrate to a reverse osmosis process to result in a permeate stream having less than about 50 parts per billion arsenic.
Claims11
A process for treating a arsenic-contaminated aqueous waste to recover usable water comprising the steps of:
- passing the arsenic-contaminated water through an ultrafilter membrane to remove solids to create an arsenic-containing aqueous filtrate
- chemically treating the filtrate to produce a filtrate having a pH of from about 6 to about 8;
- and
- subjecting the filtrate to reverse osmosis at elevated pressure of up to about 1,000 psig to yield a permeate stream having less than about 50 ppb arsenic and a reject stream containing the balance of the arsenic.
A process for recovering water from arsenic-contaminated aqueous waste stream which comprises the steps of:
- pretreating the aqueous waste streams to remove components which would reduce efficiency of or damage a reverse osmosis membrane;
- filtering the treated waste stream to remove particles of a size of greater than about 5 micron diameter;
- passing the filtered waste stream through a membrane ultrafilter to recover substantially particle-free arsenic contaminated water;
- adjusting the pH of the substantially particle-free arsenic-contaminated water to a value of from about 6 to about 8;
- and
- passing the arsenic-contaminated water through a reverse osmosis membrane to produce from about 50% to about 90% of the water as a permeate stream of useful water and a reject stream containing the arsenic;
- and
- recovering the permeate stream.
Dependencies are inferred from the claim text.