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US 6,258,278 B1Granted
High purity water production
AssigneeZenon Environmental Inc.
InventorsAnthony A. Tonelli, Eric Harrison, Susan Leanne Wesno, Hadi Husain, Andrew Benedek
Life of this patent
Estimating the term…
Abstract
A method of producing high purity water using dealkalization and a double pass reverse osmosis membrane system having enhanced membrane life.
Claims35
A method of producing high purity water using dealkalization and reverse osmosis membrane systems having enhanced membrane life, the method comprising:
- (a) providing a body of feedwater to be purified;
- (b) adding a coagulant to said body to form a floc concentration in the range of 2 to 6 gm/l in a size range of 0.2 to 10 μm in said body for adsorbing contaminants thereon;
- (c) removing a portion of said body through a submerged semi-permeable membrane to provide a purified feedwater;
- (d) treating said purified feedwater with a strong base anion exchange for purposes of dealkalization to remove ions including bicarbonate, carbonate, sulfate and nitrate ions to provide a substantially completely dealkalized water containing ions having a major portion thereof comprised of sodium and chloride ions;
- (e) removing carbon dioxide from said dealkalized water to provide dealkalized, decarbonated water substantially free of carbon dioxide;
- (f) maintaining said decarbonated water at a pH in the range of 6 to 7.7;
- (g) providing a first membrane module having a first high pressure side and a first low pressure side separated by a first membrane;
- (h) introducing said dealkalized, decarbonated water to the first high pressure side of said first membrane and producing a first permeate in said first low pressure side to provide a permeate having a pH in the range of about 6.5 to 7.5;
- (i) providing a second membrane module having a second high pressure side and a second low pressure side separated by a second membrane;
- and
- (j) introducing said first permeate to the high pressure side of said second membrane module and passing water through said second membrane producing said high purity water having a resistivity greater than 0.8 microhm-cm in the low pressure side of said second membrane.
8 more elements
A method of producing high purity water using dealkalization and reverse osmosis membrane systems having enhanced membrane life, the method comprising:
- (a) providing a body of feedwater to be purified;
- (b) adding a coagulant to said body to form a floc concentration in the range of 2 to 6 gm/l in a size range of 0.2 to 10 μm in said body for purposes of adsorbing contaminants thereon;
- (c) removing a portion of said body through a submerged semi-permeable membrane to provide a purified feedwater;
- (d) treating said purified feedwater with a strong base anion exchange for purposes of dealkalization to remove at least one of the ions from the group consisting of bicarbonate, carbonate, sulfate and nitrate ions to provide a substantially completely dealkalized water containing ions having a major portion thereof comprised of sodium and chloride ions and having a pH in the range of 4 to 6;
- (e) removing carbon dioxide from said dealkalized water to provide dealkalized, decarbonated water substantially free of carbon dioxide;
- (f) maintaining said decarbonated water at a pH in the range of 6.7 to 7.7 and having a conductivity in the range of 100 to 500 micro-Siemens;
- (g) providing a first membrane module having a high pressure side and a low pressure side separated by a first membrane;
- (h) introducing said dealkalized, decarbonated water to the high pressure side of said first membrane and producing a first permeate in said low pressure side to provide a permeate having a pH in the range of about 6.5 to 7.5;
- (i) providing a second membrane module having a high pressure side and a low pressure side separated by a second membrane;
- and
- (j) introducing said first permeate to the high pressure side of said second membrane module and passing water through said second membrane producing said high purity water having a resistivity greater than 0.8 microhm-cm in the low pressure side of said second membrane.
8 more elements
A method of producing high purity water using dealkalization and reverse osmosis membrane systems having enhanced membrane life, the method comprising:
- (a) providing a body of feedwater to be purified;
- (b) adding a coagulant to said body to form a floc in said body in a concentration range of 2 to 6 gms/l in a size range of 0.2 to 10 μm for purposes of adsorbing contaminants thereon;
- (c) removing a portion of said body through a submerged semi-permeable membrane to provide a purified feedwater;
- (d) treating said purified feedwater with an ion exchange for purposes of dealkalization to remove an ion from the group consisting of bicarbonate, carbonate, sulfate and nitrate ions to provide a substantially completely dealkalized water containing ions having a major portion thereof comprised of sodium and chloride ions and having a pH in the range of 4 to 6;
- (e) removing carbon dioxide from said dealkalized water to provide dealkalized, decarbonated water substantially free of carbon dioxide;
- (f) maintaining said decarbonated water at a pH in the range of 6.7 to 7.7 and having a conductivity in the range of 100 to 500 micro-Siemens;
- (g) providing a first membrane module having a high pressure side and a low pressure side separated by a first membrane;
- (h) introducing said dealkalized, decarbonated water to the high pressure side of said first membrane and producing a first permeate in said low pressure side to provide a permeate having a pH in the range of about 6.5 to 7.5;
- (i) providing a second membrane module having a high pressure side and a low pressure side separated by a second membrane;
- and
- (j) introducing said first permeate to the high pressure side of said second membrane module and passing water through said second membrane producing said high purity water having a resistivity greater than 0.8 microhm-cm in the low pressure side of said second membrane.
8 more elements
A method of producing high purity water using dealkalization and reverse osmosis membrane systems having enhanced membrane life, the method comprising:
- (a) providing a feedwater to be purified;
- (b) treating said feedwater with a strong base anion exchange for purposes of dealkalization to remove ions including bicarbonate, carbonate, sulfate and nitrate ions to provide a substantially completely dealkalized water contaaing ions having a major portion thereof comprised of sodium and chloride ions;
- (c) removing carbon dioxide from said dealkalized water to provide dealkalized, decarbonated water substantially free of carbon dioxide;
- (d) maintaiing said decarbonated water at a pH in the range of 6 to 9.5;
- (e) providing a first membrane module having a first high pressure side and a first low pressure side separated by a first membrane;
- (f) introducing said dealkalized, decarbonated water to the high pressure side of said first membrane and producing a first permeate in said low pressure side having a pH in the range of about 6.5 to 7.5;
- (g) providing a second membrane module having a high pressure side and a low pressure side separated by a second membrane;
- (h) introducing said first permeate to the high pressure side of said second membrane module and passing water through said second membrane producing said high purity water having a resistivity greater than 0.8 microhm-cm in the low pressure side of said second membrane;
- (i) measuring the resistivity of said high purity water produced at said second low pressure side of said second membrane module to provide a resistivity measurement;
- (j) relaying said resistivity measurement to a programmable logic controller;
- (k) in said programmable logic controller, comparing said resistivity measurement with a previous resistivity measurement to provide a comparson;
- and
- (l) in response to said comparison, maintaining or changing the pH of said dealkalized, decarbonated water upwardly or downwardly to produce said high purity water having said desired resistivity.
10 more elements
A method of producing high purity water using dealkalization and reverse osmosis membrane systems having enhanced membrane life, the method comprising:
- (a) providing a feedwater to be purified;
- (b) treating said feedwater with a strong base anion exchange for purposes of dealkalization to remove ions including at least one of the ions selected from the group consisting of bicarbonate, carbonate, sulfate and nitrate ions to provide a substantially completely dealkalized water containing ions having a major portion comprised of sodium and chloride ions and having a pH in the range of 4 to 6;
- (c) removing carbon dioxide from said dealkalized water to provide dealkalized, decarbonated water substantially free of carbon dioxide;
- (d) maintaining said decarbonated water at a pH in the range of 6.7 to 7.7 and having a conductivity in the range of 100 to 750 micro-Siemens;
- (e) providing a first membrane module having a high pressure side and a low pressure side separated by a first membrane;
- (f) introducing said dealkalized, decarbonated water to the high pressure side of said first membrane and producing a first permeate in said low pressure side to provide a permeate having a pH in the range of about 6.5 to 7.5;
- (g) providing a second membrane module having a high pressure side and a low pressure side separated by a second membrane;
- (h) introducing said first permeate to the high pressure side of said second membrane module and passing water through said second membrane producing said high purity water having a resistivity greater than 0.8 microhm-cm in the low pressure side of said second membrane,
- (i) measuring the resistivity of said high purity water produced at said second low pressure side of said second membrane module to provide a resistivity measurement;
- (j) relaying said resistivity measurement to a programmable logic controller;
- (k) in said programmable logic controller, comparing said resistivity measurement with a previous resistivity measurement to provide a comparison;
- and
- (l) in response to said comparison, maintaining or changing the pH of said dealkalized, decarbonated water upwardly or downwardly to produce said high purity water having said desired resistivity.
10 more elements
Dependencies are inferred from the claim text.