CA1191627A - Trihalomethane precursor removal using ion exchange emulsions - Google Patents
Trihalomethane precursor removal using ion exchange emulsionsInfo
- Publication number
- CA1191627A CA1191627A CA000419667A CA419667A CA1191627A CA 1191627 A CA1191627 A CA 1191627A CA 000419667 A CA000419667 A CA 000419667A CA 419667 A CA419667 A CA 419667A CA 1191627 A CA1191627 A CA 1191627A
- Authority
- CA
- Canada
- Prior art keywords
- water
- resin
- ion exchange
- submicroscopic
- thm
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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- Treatment Of Water By Ion Exchange (AREA)
- Separation Of Suspended Particles By Flocculating Agents (AREA)
Abstract
- i -PATENT APPLICATION OF
Eric G. Isacoff and James W. Neely for TRIHALOMETHAME PRECURSOR REMOVAL
USING ION EXCHANGE EMULSIONS
Abstract of the Disclosure To avoid formation of toxic trihalomethanas in drinking waters disinfected with halogens, these waters are treated with submicroscopic ion exchange resin particles, optionally in the presenoe of a metal salt coagulant, to remove the trihalomethane precursors prior to halogenation.
Eric G. Isacoff and James W. Neely for TRIHALOMETHAME PRECURSOR REMOVAL
USING ION EXCHANGE EMULSIONS
Abstract of the Disclosure To avoid formation of toxic trihalomethanas in drinking waters disinfected with halogens, these waters are treated with submicroscopic ion exchange resin particles, optionally in the presenoe of a metal salt coagulant, to remove the trihalomethane precursors prior to halogenation.
Description
T~IHALOMETHANE PRECURSOR REMOVAL
NS
Back~round of the Inventi n The ubiquitous use of chlorine as a disinfectant in public water supplies has introduced a subtle health hazard of its own. Chlorine has been shown to react with humic substances present in such waters to produce trihalomethanes (THM) such as chloroform. The Environmental Protection Agency has identified trihalomethanes as carcinogens in animals, and has published a maximum contaminant level of 0.10 mg/liter (lOO ppb) for total THM in communit~ water s~stems (National Interim Primary Drinking Water Regulations;
Control of Trihalomethanes in Drinking Water; Final Rules. U.S. Environmental Protection Agency, Federel Register, Vol. 44, No. 231, November 29, 1979)o Attempts at removing trihalomethanes from chlorinated drinking water have met with but limited success. If THM i5 removad, ~ut residual chlorine and humic substances remain, the THM will re-form. If the active chlorine is removed, as with granular ~'.
6~7 activated charcoal, the water must be re-chlorinated to meet standards, and THM again may re form.
An alternative approach is to remove the humic substances that are THM precursors. These substances are found in many natural waters, are probably leached from organic materials found in soil, and are usually found at high concentrations in surface waters, and at lower concentrations in most ground waters. Materials that previously have been used for removing them from water include adsorbents such as granular activated carbon, coagulants such as alum and ferric sulfate, and conventional ion exchange resins, especially weakly basic anion exchanga resins. Each o~ these processes shares the problem that relatively large amounts of lS treating agents must be added to the drinking water to effectively reduce the THM precursor levels to below permissible limits. In addition, each possesses additional problems o~ its own, some of which are described above.
Accordingly, an object o~ the present invention i9 to minimize the amount of treating agent that must be added to water to signi~icantly reduce its T~IM
precursor content. Another obJect is to remove THM
precursors in a way that does not interfere with conventional drinking water disinfectant processes.
Additional objects will beoome apparent upon consideration of the follol~ing disclosure.
The Invention .
~e have diqcovered a process for removing the precursors of trihalomethane ~rom water, and especially from drinking water containing such trihalomethane precursors, which comprises treating the water with submicroscopic ion exchange resin particles having a diameter smaller than about 1.5,~ m. The submicroscopic ion exchange particles may be anion exchange particles alone, or ani~n exchange particles combined with cation exchange particles in the ~orm of a ~loc. These submicroscopic ion exchange particles are surprisingly e~fective in removing THM precursors, and are effective at surprisingly low concentrations.
The preferred treatment levels for removal of THM from drinking water are ~rom about 1 to about 50 milligrams per liter of water (mg/l), and more preferably about 10 mg/l or lessO
A convenient process by which water such as drinking water may be treated according to the process oP the present invention is to introduce the sub~icroscopic anion exchange resin in the ~orm of an lS emulsion, or to introduce a water~suspended floc of the anion and cation exchange resins, into the water prior to the settling and filtration treatment normally given to waters during pu-ification for drinking purposes.
It i9 beneficial to combine coagulant treatment and treatment with the submicroscopic anion exchange resin. Coagulant treatment is a well-known water treatment process; the coasulants used are similarly well known and include soluble polyelectrolytes, which may be cationic, anionic or nonionic polyelectrolytes, including polyacrylic acid and soluble, polymeric quaternary amines. The coagulants may also be metal salts, including the sulfates and chlorides of aluminum, ferrous and ferric ircn, magnesium carbonate and aluminum silicates including clays. Other coagulants will be aPParent to those skillea in the art. The coagulant treatment may occur prior to, simultaneous with, or subsequent to treatment with the submicroscopic anion exchange resin; it should preferably occur prior to any filtration step.
In the absence of a coagulant cr L locculant that ;~ ~
~ ~`
will flocculate any excess submicroscopic cation exchange resin, either present in the water prior to treatment or introduced as described above, the resin may pa~s through ~ubsequent filters and produce turbidity. Treatment with a soluble cationic flocculant or submicroscopic cation exchange resin may be necessary to prevent this turbidity. The conventional settling and filtration step removes the flocculated resin, and with it the THM precursors, ~rom the water. Chlorination or other disinfectant processes may be applied at any point during the water treatment, but desirably the disinfectant should be introduced subse~uent to treatment with, and more desirably subsequent to removal o~, the submicroscoDic ion exchange resins. Chlorination prior to treatment with the submicroscopic ion exchange resin allows the THM precursors to react with the chlorine prior to their removal, thus defeating the purpose of the present process, and chlorination prior to removal of the submicroscopic ion exc~ange resin allows the resin itself to react with the chlorine. The consequence of the latter reaction is unknown, but inasmuch as it introduces chlorinated organic materials tu the drinking water, it is considered undesirable.
The submicroscopic ion exchange particles ussd in the process of the present invention are those resins having a diameter of 1.5,ti m or smaller, and bearing from about 0.7 to about 1.5 ion exchange functional groups ~er monomer unit. Such submicroscopic ion exchange resins may be prepared as taught in U.S. Patent No.
4,200,695, of B.P. Chong et al, issued ~pril 29, 1980, said patent being assigned to Rchm and Haas Company.
The follow~ng examples are intended to illustrate the present invention, but not to limit it except as it is limited in the claims. All reagents used are of good commercial quality, and all percentages and other proportions are by weight, unless otherwise indicated.
In the following examples, samples of raw water were treated according to the process of the present invention, and for comparative purposes, according to conventional processes. Raw water was collected from the Delaware River at Philadelphia, Pennsylvania, filtared through a coarse screen, and sub~equently filtered through glass wool prior to testing. Raw water was sampled by the U.S. Environmental Protection Agency from the Ohio River at Cinoinnati, Ohio, and from the Preston Water Treatment Plant at Hialeah, Florida; these samples were tested as supplied.
The experimental procedure used was similar for each of the following examples. For the small-scale examples the material to be tested was added to 800 ml of the specified test water in a 1000-ml beaker. The submicroscopic ion exchange resins were added as aqueous suspensions containing 6.25% solids, and the other THM-precursor removers were added as dry solids. The water oontaining the THM-precursor removers to be tested was stirred for 5 minutes at 100 rpm using a Phipps and Bird jar test appanatus, and for an additional 20 minutes at 30 rpm, after which the water was allowed to stand undisturbed while the solidæ
settled. At 30 and 60 minut0s during the settling ; period the turbidity of the water was determined using a Hellige Turbidimeter and APHA Method No. 163b (APHA
Standard Methods, 13th edition, 1971~; if a sample containing the submicroscopic anion exchange resin still showed turbidity after 60 minutes of settling, a small amount of submicroscopic cation exchangs resin was added to flocculate the excsss anion exchange 6~
rssin. Subsaquent to the settlin~ period the water samples were filtered using"Whatman'i~1 filter paper.
Several 50-ml samples of the treated, filtered water were chlorinated to different levels of chlorine, using an approximately 4000-6000 ppm stock solution of chlorine gas dissolved in water; these chlorinated samples were allowed to stand in the dark ~or 24 hours, after which they were analyzed for chlorine spectrophotometrically using APHA Method No. 114g (APHA
Standard Methods, 13th edition, 1971~, to determine the sample containing a residual chlorine content of 1.0-1.5 ppm chlorine after 24 hours. The sample containing this specified amount of chlorine after 24 hours was treated with 0.25 ml of O.lN sodium thiosulfate to reduce the free chlorine and prevent further chlorination during analysis. The THM formed during the 24-hour period was determined using a gas-liquid chromatograph with electron-capture detector, direct injection of the aqueous sample, and similar injection of aqueous chloroform standards.
Examples 1-29, the results of which are given in Table 1, illustrate the removal of THM precursors, as evidenced by the reduction in THM following overnight chlorination, by a strongly ba ic, submicroscopic anion exchange resin of the present invention, in the hydroxyl form. In Examples 1~10 and 23 29 the tested waters were samples of Delaware River water, in Examples 11-16 they were settled Ohio River water, and in Examples 17-22 they were raw waters from the Preston Water Treatment Plant in Hialeah, Florida.
* Trad~k Treatment THM Gontent Level ~ g~ THM
Example (m~ Treated Control Reduction 1 1 66 100 34.0
NS
Back~round of the Inventi n The ubiquitous use of chlorine as a disinfectant in public water supplies has introduced a subtle health hazard of its own. Chlorine has been shown to react with humic substances present in such waters to produce trihalomethanes (THM) such as chloroform. The Environmental Protection Agency has identified trihalomethanes as carcinogens in animals, and has published a maximum contaminant level of 0.10 mg/liter (lOO ppb) for total THM in communit~ water s~stems (National Interim Primary Drinking Water Regulations;
Control of Trihalomethanes in Drinking Water; Final Rules. U.S. Environmental Protection Agency, Federel Register, Vol. 44, No. 231, November 29, 1979)o Attempts at removing trihalomethanes from chlorinated drinking water have met with but limited success. If THM i5 removad, ~ut residual chlorine and humic substances remain, the THM will re-form. If the active chlorine is removed, as with granular ~'.
6~7 activated charcoal, the water must be re-chlorinated to meet standards, and THM again may re form.
An alternative approach is to remove the humic substances that are THM precursors. These substances are found in many natural waters, are probably leached from organic materials found in soil, and are usually found at high concentrations in surface waters, and at lower concentrations in most ground waters. Materials that previously have been used for removing them from water include adsorbents such as granular activated carbon, coagulants such as alum and ferric sulfate, and conventional ion exchange resins, especially weakly basic anion exchanga resins. Each o~ these processes shares the problem that relatively large amounts of lS treating agents must be added to the drinking water to effectively reduce the THM precursor levels to below permissible limits. In addition, each possesses additional problems o~ its own, some of which are described above.
Accordingly, an object o~ the present invention i9 to minimize the amount of treating agent that must be added to water to signi~icantly reduce its T~IM
precursor content. Another obJect is to remove THM
precursors in a way that does not interfere with conventional drinking water disinfectant processes.
Additional objects will beoome apparent upon consideration of the follol~ing disclosure.
The Invention .
~e have diqcovered a process for removing the precursors of trihalomethane ~rom water, and especially from drinking water containing such trihalomethane precursors, which comprises treating the water with submicroscopic ion exchange resin particles having a diameter smaller than about 1.5,~ m. The submicroscopic ion exchange particles may be anion exchange particles alone, or ani~n exchange particles combined with cation exchange particles in the ~orm of a ~loc. These submicroscopic ion exchange particles are surprisingly e~fective in removing THM precursors, and are effective at surprisingly low concentrations.
The preferred treatment levels for removal of THM from drinking water are ~rom about 1 to about 50 milligrams per liter of water (mg/l), and more preferably about 10 mg/l or lessO
A convenient process by which water such as drinking water may be treated according to the process oP the present invention is to introduce the sub~icroscopic anion exchange resin in the ~orm of an lS emulsion, or to introduce a water~suspended floc of the anion and cation exchange resins, into the water prior to the settling and filtration treatment normally given to waters during pu-ification for drinking purposes.
It i9 beneficial to combine coagulant treatment and treatment with the submicroscopic anion exchange resin. Coagulant treatment is a well-known water treatment process; the coasulants used are similarly well known and include soluble polyelectrolytes, which may be cationic, anionic or nonionic polyelectrolytes, including polyacrylic acid and soluble, polymeric quaternary amines. The coagulants may also be metal salts, including the sulfates and chlorides of aluminum, ferrous and ferric ircn, magnesium carbonate and aluminum silicates including clays. Other coagulants will be aPParent to those skillea in the art. The coagulant treatment may occur prior to, simultaneous with, or subsequent to treatment with the submicroscopic anion exchange resin; it should preferably occur prior to any filtration step.
In the absence of a coagulant cr L locculant that ;~ ~
~ ~`
will flocculate any excess submicroscopic cation exchange resin, either present in the water prior to treatment or introduced as described above, the resin may pa~s through ~ubsequent filters and produce turbidity. Treatment with a soluble cationic flocculant or submicroscopic cation exchange resin may be necessary to prevent this turbidity. The conventional settling and filtration step removes the flocculated resin, and with it the THM precursors, ~rom the water. Chlorination or other disinfectant processes may be applied at any point during the water treatment, but desirably the disinfectant should be introduced subse~uent to treatment with, and more desirably subsequent to removal o~, the submicroscoDic ion exchange resins. Chlorination prior to treatment with the submicroscopic ion exchange resin allows the THM precursors to react with the chlorine prior to their removal, thus defeating the purpose of the present process, and chlorination prior to removal of the submicroscopic ion exc~ange resin allows the resin itself to react with the chlorine. The consequence of the latter reaction is unknown, but inasmuch as it introduces chlorinated organic materials tu the drinking water, it is considered undesirable.
The submicroscopic ion exchange particles ussd in the process of the present invention are those resins having a diameter of 1.5,ti m or smaller, and bearing from about 0.7 to about 1.5 ion exchange functional groups ~er monomer unit. Such submicroscopic ion exchange resins may be prepared as taught in U.S. Patent No.
4,200,695, of B.P. Chong et al, issued ~pril 29, 1980, said patent being assigned to Rchm and Haas Company.
The follow~ng examples are intended to illustrate the present invention, but not to limit it except as it is limited in the claims. All reagents used are of good commercial quality, and all percentages and other proportions are by weight, unless otherwise indicated.
In the following examples, samples of raw water were treated according to the process of the present invention, and for comparative purposes, according to conventional processes. Raw water was collected from the Delaware River at Philadelphia, Pennsylvania, filtared through a coarse screen, and sub~equently filtered through glass wool prior to testing. Raw water was sampled by the U.S. Environmental Protection Agency from the Ohio River at Cinoinnati, Ohio, and from the Preston Water Treatment Plant at Hialeah, Florida; these samples were tested as supplied.
The experimental procedure used was similar for each of the following examples. For the small-scale examples the material to be tested was added to 800 ml of the specified test water in a 1000-ml beaker. The submicroscopic ion exchange resins were added as aqueous suspensions containing 6.25% solids, and the other THM-precursor removers were added as dry solids. The water oontaining the THM-precursor removers to be tested was stirred for 5 minutes at 100 rpm using a Phipps and Bird jar test appanatus, and for an additional 20 minutes at 30 rpm, after which the water was allowed to stand undisturbed while the solidæ
settled. At 30 and 60 minut0s during the settling ; period the turbidity of the water was determined using a Hellige Turbidimeter and APHA Method No. 163b (APHA
Standard Methods, 13th edition, 1971~; if a sample containing the submicroscopic anion exchange resin still showed turbidity after 60 minutes of settling, a small amount of submicroscopic cation exchangs resin was added to flocculate the excsss anion exchange 6~
rssin. Subsaquent to the settlin~ period the water samples were filtered using"Whatman'i~1 filter paper.
Several 50-ml samples of the treated, filtered water were chlorinated to different levels of chlorine, using an approximately 4000-6000 ppm stock solution of chlorine gas dissolved in water; these chlorinated samples were allowed to stand in the dark ~or 24 hours, after which they were analyzed for chlorine spectrophotometrically using APHA Method No. 114g (APHA
Standard Methods, 13th edition, 1971~, to determine the sample containing a residual chlorine content of 1.0-1.5 ppm chlorine after 24 hours. The sample containing this specified amount of chlorine after 24 hours was treated with 0.25 ml of O.lN sodium thiosulfate to reduce the free chlorine and prevent further chlorination during analysis. The THM formed during the 24-hour period was determined using a gas-liquid chromatograph with electron-capture detector, direct injection of the aqueous sample, and similar injection of aqueous chloroform standards.
Examples 1-29, the results of which are given in Table 1, illustrate the removal of THM precursors, as evidenced by the reduction in THM following overnight chlorination, by a strongly ba ic, submicroscopic anion exchange resin of the present invention, in the hydroxyl form. In Examples 1~10 and 23 29 the tested waters were samples of Delaware River water, in Examples 11-16 they were settled Ohio River water, and in Examples 17-22 they were raw waters from the Preston Water Treatment Plant in Hialeah, Florida.
* Trad~k Treatment THM Gontent Level ~ g~ THM
Example (m~ Treated Control Reduction 1 1 66 100 34.0
2 3 - 54 100 46.0
3 5 44 100 56.0
4 7 32 100 68.0 6 1 124 138 10.1 7 3 70.6 138 50.7 8 5 36.1 138 73.8 9 7 34.9 138 74.7 9 30.2 138 78.1 11 2 120 148 18.9 ~ 12 5 84 148 43.2 ;~ 13 10 87 148 41.2 ~` 14 15 67 148 54.7 148 62.8 16 25 56 148 62.1 17 2 340 600 43.3 18 5 360 600 40.0 19 10 319 600 46.8 242 600 59.7 21 20 232 600 61.3 22 25 176 600 70.7 23 7.8 35 148 76.2 24 15.7 25 148 82.8 23.5 29 148 80.4 26 31.3 37 148 75.0 27 39.1 ~o 148 86.4 28 31.3 32 87 63.6 29 62.5 34 87 63.1 - .~
Examples 30-34, the results of which are given in Table Z, illustrate the removal of trihalomethane precursors from Delaware River water samples by a strongly basic, submicro~copic ion exchange resin of the present invention, in the chloride form.
Treatment THM Content Level (~Ig/l) % THM
Example (mg/l) Treated Control Reduction 1 124 136 8.8 31 3 52.6 136 61.3 32 5 25.1 136 81.5 33 7 23.1 136 82.8 34 9 19.1 136 85.9 6~7~
Examples 35-39, the results of which are given in Table 3, illustrate the removal of trihalomethane precursors from Delaware River water with a floc of the present invention formed by mixing the strongl~y basic S submicroscopic ion exchange resin of Examples 1-29 with a strongly acidic, submicroscopic ion exchange resin.
Treal;ment THM Content Level(~g/l) % THM
Examvle (mg/l)Treated Control Reduction 72 110 34.7 37 62.5 58 ~7 32.8 38 125 62 87 28.4 39 250 52 87 ~l0.5 Example 40 illustrates the removal of trihalomethane precurqors from Delaware River water with a mixture of lO mg/l of ferric sulfate (a krown coagulant) and 9 mg/l of the strongly basic, submicroscopic ion exchange resin of the present invention. Examples 41-45 illustrate, for comparative purposes, the removal of trihalome.thane precursors from Delaware River water by ferric sulfate alone. The results of Examples 40-45 are given in Table 4.
Treatment THM Content Level ~ g/l) % THM
Example (m~/l) Treated Control Reduction 10 ~ 9 16 71 77.5 41 10 65 71 8.5 42 20 48 71 32.4 43 30 36 71 49.3 44 40 31 71 56.3 26 71 63.4 - ll Examples 46-54, the results o~ which are given in Table 5, illustrate ~or comparative purposes the removal of trihalomethane precursors from Delaware River water by conventional treatment with alum, or aluminum sulPate-16 hydrate.
Treatment THM Content Level(~ g/l) ~ THM
Exam~le ~m~!l)Treated Control Reduction 51 50 34 87 60.9 52 50 25 148 83.2 53 50 49 110 55.1 54 100 41 110 63.1 Examples 55 and 56, the results of which are given in Table 6, illustrate for comparative purposes the removal of trihalomethane precursors from Delaware River water by conventional treatment with activated charcoal (Pittsburgh RC Pulverized Grade, obtained from Calgon Corporation).
Treatment THM Content Level(~g/l) ~ THM
Example (mg/l)Treated Control Reduction 5079 110 28.5 56 100 42 110 61.9 Examples 57-61, the results of wh.ich are glven in Table 7, illustrate for comparative purposes the removal of trihalomethane precursors from Delaware River water by treatment with soluble cationic polymers ~etz 1175~. These examples are included to compare the effectiveness of low level treatment with the insoluble submicroscopic ion exchange re~in~ o~ the present invention with similar ionic, but soluble9 materials which have been previously used for removal : lO of anionic material~q from water.
Treatment THM Content Level ~ g/1~ ~ THM
Example(mg/1~ Treated_ Control Reduction lS 57 5 168 176 4.5 58 10 122 176 30.6 59 15 91.9 176 47.7 84.5 176 51.1 61 25 40.4 176 77.0 * Trademark
Examples 30-34, the results of which are given in Table Z, illustrate the removal of trihalomethane precursors from Delaware River water samples by a strongly basic, submicro~copic ion exchange resin of the present invention, in the chloride form.
Treatment THM Content Level (~Ig/l) % THM
Example (mg/l) Treated Control Reduction 1 124 136 8.8 31 3 52.6 136 61.3 32 5 25.1 136 81.5 33 7 23.1 136 82.8 34 9 19.1 136 85.9 6~7~
Examples 35-39, the results of which are given in Table 3, illustrate the removal of trihalomethane precursors from Delaware River water with a floc of the present invention formed by mixing the strongl~y basic S submicroscopic ion exchange resin of Examples 1-29 with a strongly acidic, submicroscopic ion exchange resin.
Treal;ment THM Content Level(~g/l) % THM
Examvle (mg/l)Treated Control Reduction 72 110 34.7 37 62.5 58 ~7 32.8 38 125 62 87 28.4 39 250 52 87 ~l0.5 Example 40 illustrates the removal of trihalomethane precurqors from Delaware River water with a mixture of lO mg/l of ferric sulfate (a krown coagulant) and 9 mg/l of the strongly basic, submicroscopic ion exchange resin of the present invention. Examples 41-45 illustrate, for comparative purposes, the removal of trihalome.thane precursors from Delaware River water by ferric sulfate alone. The results of Examples 40-45 are given in Table 4.
Treatment THM Content Level ~ g/l) % THM
Example (m~/l) Treated Control Reduction 10 ~ 9 16 71 77.5 41 10 65 71 8.5 42 20 48 71 32.4 43 30 36 71 49.3 44 40 31 71 56.3 26 71 63.4 - ll Examples 46-54, the results o~ which are given in Table 5, illustrate ~or comparative purposes the removal of trihalomethane precursors from Delaware River water by conventional treatment with alum, or aluminum sulPate-16 hydrate.
Treatment THM Content Level(~ g/l) ~ THM
Exam~le ~m~!l)Treated Control Reduction 51 50 34 87 60.9 52 50 25 148 83.2 53 50 49 110 55.1 54 100 41 110 63.1 Examples 55 and 56, the results of which are given in Table 6, illustrate for comparative purposes the removal of trihalomethane precursors from Delaware River water by conventional treatment with activated charcoal (Pittsburgh RC Pulverized Grade, obtained from Calgon Corporation).
Treatment THM Content Level(~g/l) ~ THM
Example (mg/l)Treated Control Reduction 5079 110 28.5 56 100 42 110 61.9 Examples 57-61, the results of wh.ich are glven in Table 7, illustrate for comparative purposes the removal of trihalomethane precursors from Delaware River water by treatment with soluble cationic polymers ~etz 1175~. These examples are included to compare the effectiveness of low level treatment with the insoluble submicroscopic ion exchange re~in~ o~ the present invention with similar ionic, but soluble9 materials which have been previously used for removal : lO of anionic material~q from water.
Treatment THM Content Level ~ g/1~ ~ THM
Example(mg/1~ Treated_ Control Reduction lS 57 5 168 176 4.5 58 10 122 176 30.6 59 15 91.9 176 47.7 84.5 176 51.1 61 25 40.4 176 77.0 * Trademark
Claims (13)
1. A process for removing trihalomethane precursors from water containing said precursors which comprises treating the water with submicroscopic anion exchange resin having an average particle diameter smaller than 1.5 micrometers, and subsequently removing the resin from the water.
2. The process of Claim 1 wherein the water is treated with the resin at a rate of 50 milligrams or less of resin per liter of water.
3. The process of Claim 1 wherein the water is treated with the resin at a rate of from about 1 to about 10 milligrams of resin per liter of water.
4. The process of Claim 1 wherein the resin is removed from the water by filtration.
5. The process of Claim 4 wherein removing the resin by filtration is facilitated by adding to the water, prior to filtration, a submicroscopic cation exchange resin having an average particle diameter smaller than 1.5 micrometers.
6. The process of Claim 1 wherein the resin is introduced to the water in the form of an aqueous emulsion.
7. The process of Claim 1 wherein the resin is introduced to the water in the form of a floc with a submicroscopic cation exchange resin having an average particle diameter smaller than 1.5 micrometers.
8. The process of Claim 1 wherein the water is treated with the resin in the presence of a metal salt coagulant.
9. The process of Claim 8 wherein the metal salt coagulant is a clay.
10. The process of Claim 8 wherein the metal salt coagulant is ferric sulfate.
11. The process of Claim 8 wherein the metal salt coagulant is present in the water at a level greater than about 5 milligrams per liter of water.
12. The process of Claim 1 wherein the resin is in the hydroxyl form.
13. The process of Claim 1 wherein the resin is in the halide form.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US34458482A | 1982-02-01 | 1982-02-01 | |
| US344,584 | 1982-02-01 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1191627A true CA1191627A (en) | 1985-08-06 |
Family
ID=23351141
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000419667A Expired CA1191627A (en) | 1982-02-01 | 1983-01-18 | Trihalomethane precursor removal using ion exchange emulsions |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS58133837A (en) |
| CA (1) | CA1191627A (en) |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4380590A (en) * | 1978-09-19 | 1983-04-19 | Rohm And Haas Company | Emulsion copolymer cation exchange resins |
-
1983
- 1983-01-18 CA CA000419667A patent/CA1191627A/en not_active Expired
- 1983-02-01 JP JP58013836A patent/JPS58133837A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0325225B2 (en) | 1991-04-05 |
| JPS58133837A (en) | 1983-08-09 |
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