CA1315236C - Ozone-generating electrolytic cell provided with a solid electrolyte for treating water - Google Patents
Ozone-generating electrolytic cell provided with a solid electrolyte for treating waterInfo
- Publication number
- CA1315236C CA1315236C CA000531368A CA531368A CA1315236C CA 1315236 C CA1315236 C CA 1315236C CA 000531368 A CA000531368 A CA 000531368A CA 531368 A CA531368 A CA 531368A CA 1315236 C CA1315236 C CA 1315236C
- Authority
- CA
- Canada
- Prior art keywords
- water
- sidestream
- ozone
- electrolytic cell
- stream
- 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 - Fee Related
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
- C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
- C02F1/467—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electrochemical disinfection; by electrooxydation or by electroreduction
- C02F1/4672—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electrochemical disinfection; by electrooxydation or by electroreduction by electrooxydation
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B1/00—Electrolytic production of inorganic compounds or non-metals
- C25B1/01—Products
- C25B1/13—Ozone
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/72—Treatment of water, waste water, or sewage by oxidation
- C02F1/78—Treatment of water, waste water, or sewage by oxidation with ozone
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
- C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
- C02F1/46104—Devices therefor; Their operating or servicing
- C02F1/46109—Electrodes
- C02F2001/46133—Electrodes characterised by the material
- C02F2001/46138—Electrodes comprising a substrate and a coating
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
- C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
- C02F1/46104—Devices therefor; Their operating or servicing
- C02F1/46109—Electrodes
- C02F2001/46152—Electrodes characterised by the shape or form
- C02F2001/46157—Perforated or foraminous electrodes
- C02F2001/46161—Porous electrodes
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2201/00—Apparatus for treatment of water, waste water or sewage
- C02F2201/46—Apparatus for electrochemical processes
- C02F2201/461—Electrolysis apparatus
- C02F2201/46105—Details relating to the electrolytic devices
- C02F2201/46115—Electrolytic cell with membranes or diaphragms
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2301/00—General aspects of water treatment
- C02F2301/04—Flow arrangements
- C02F2301/043—Treatment of partial or bypass streams
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Metallurgy (AREA)
- Materials Engineering (AREA)
- Inorganic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- Treatment Of Water By Oxidation Or Reduction (AREA)
- Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
- Water Treatment By Electricity Or Magnetism (AREA)
Abstract
ABSTRACT OF THE DISCOSURE
Tap water is ozonized, using an electro-lytic cell provided with a solid electrolyte, by first dividing the freshwater stream into a main-stream and a sidestream and only feeding the latter via a water-softening unit to the electrolytic cell.
The ozonized sidestream is recombined with the main-stream in the mixer. The fractional rate of water of the sidestream is advantageously 0.5 to 3% by volume of that of the freshwater stream.
Tap water is ozonized, using an electro-lytic cell provided with a solid electrolyte, by first dividing the freshwater stream into a main-stream and a sidestream and only feeding the latter via a water-softening unit to the electrolytic cell.
The ozonized sidestream is recombined with the main-stream in the mixer. The fractional rate of water of the sidestream is advantageously 0.5 to 3% by volume of that of the freshwater stream.
Description
1 - 3 ~
The inven-tion concerns a process for ozonizing tap water, by the water electrolysis method and to equipment for ozonizing tap water using an ozone-generating electrolytic cell.
Ozonization is frequently used for the sterilisation of tap water. The conventional processes for this can be divided into the following part steps:
- Air preparation (drying) - Ozone generation by silent electric discharge - Contacting the tap water with the ozone-containing air stream (for example in a bubble column) - Removal of residual ozone, compare, for example C.M. Robson, "Design Engineering Aspects of Ozonation Systems", Handbook of Ozone Technology and Applications, R.G. Rice and A. Netzer, Editors, Volume 1, Ann Arbor, 1982.
The conventional processes as a rule require involved and expensive equipment, in parti-cular with respect to mixing of the tap water with the ozone-containing air.
It has been proposed in the past to generate ozone by electrolytic means, using highly pure water (compare H.-P. Klein and S. Stucki, "The Production of Ozone by Electrolysis and its Appli-cation in high-purity Water Systems", Conference Proceedings 7th Ozone World Congress, September ' . .
.~ ~
9-12, 1985, Tokyo; US-A-4,416,747).
The processes described above are less suitable for doping tap water with ozone, since large quantities must be handled and a considerable amount of apparatus is required. If the electrolytic process were used directly~ the cell would be blocked within a relatively short time by the divalent cations present in the tap water, so that its direct use would be uneconomical.
There is therefore a demand for improving and simplifying the known methods and equipment.
It is the object of the invention to pro-vide equipment and a process, by means of which tap water can be doped with ozone in a simple and economical manner and without great expense on apparatus.
In accordance with the invention there is provided a process for ozonizing tap water by a water electrolysis method using a solid electrolyte, characterized in tnat a freshwater stream is divided into a mainstream and a sidestream, in that the water of the sidestream is softened in a water-softening unit and is fed to an electrolytic cell and ozonized, and in that the resulting doped sidestream is com-bined with the mainstream in a mixer, the sidestreamamounting to 0.5 to 3% by volume of the rate of the freshwater stream and its ozone concentration down-stream of the electrolytic cell being 30-120 g per m3 of H2O.
From a different aspect, and in accordance with the invention, there is provided equipment for ozonizing tap water, using an ozone-generating electrolytic ceil provided with a solid electrolyte, which comprises an inlet line for the freshwater stream, a line for the mainstream and also a line for the sidestream in which there is a water-softening ,, ~
_ 3 _ ~3~
unit and, downstream of the latter, an e:Lectrolytic cell, and additionally a mixer at the point of con~
fluence of the main and side streams.
The invention is described by reference to the following illustrative example explained in more detail by a figure.
Figure 1 shows a flow chart of -the process and the diagrammatic structure of the equipment.
is the freshwater stream which is fed to the equip-ment and which, on entry, is divided into the main-stream 2 and the sidestream 3. 4 is a two-part water-softening unit which is connected to 3 via two isolation valves and the individual chambers (4) of which are operated alternately. The intermittent feed of NaCl as a regenerating salt is indicated by arrows. 5 represents an electrolytic cell which has a solid electrolyte and which dopes the desalinated sidestream 3 with ozone. The two streams 2 and 3 are combined again and intimately mixed in the mixer 6.
Illustrative Example:
A unit in accordance with the figure showed the ~ollowing operating parameters:
Tap water system pressure: 10 bar (freshwater stream) freshwater rate (1): 2 m3/h Water rate in mainstream (2); 1.97 m3/h Water rate in sidestream (3): 0.03 m3/h Operating current of the 03 cell (S): 40 A
Corresponding current density: 1.33 A/cm2 Electrode area of the 03 cell: 30 cm2 Cell voltage: 4.1 V
03 concentration downstream of cell (S): 60 g/m3 03 concentration downstream of mixer (6): 0.9 g/m3 . -. .
J
- 3a ~
As the water-softening unit 4, two cation exchanger columns were used, which were regenerated at intervals with an NaCl solution. This tandem operation allowed a continuous procedure. The side-stream 3 was passed from the water-softening unit 4 into the anode space of an electrolytic cell. The latter was provided with a solid electrolyte in the form of a perfluorinated ion exchanger membrane (trade mark "Nafion" from Du Pont). On either side of the membrane, there were porous electrodes which were pressed against each other under a surface pressure of 400 N/cm . The positive electrode (anode) consisted of a 1 mm thick porous titanium plate coated with PbO2, whereas the negative elect-rode (cathode) used was a porous composite of graphite and polytetrafluoroethylene. A thin plati-num Layer, acting as an electro-catalyst, was arranged between the cathode and the solid electrolyte.
When a direct current flows through the electrolytic cell, ,,,,~
-- ~3~
a mixture of oxygen and ozone is evolved at the anode.
The 2/3 ratio is on average 85% by weight to 15% by weight.
A probe for measuring the percentage quantity of ozone dissolved in the water of sidestream 3 was fitted immediately downstream of the electrolytic cell 5. In the mixer 6, the ozone-containing sidestream 3 was combined with the main-stream 2. The mixer 6 was designed as a static mixer.
The advantages of this process are that the water-softening unit 4 and the electrolytic cell 5 have to be sized only for the water rate of the sidestream 3 and that there is no poisoning of the electrolytic cell by divalent cations (above all calcium) present in the tap water.
Preferably, the fractional rate of the sidestream 3 can be 0.5 to 3% by volume of the rate of the freshwater stream 1, its ozone concentration downstream of the electrolytic cell 5 advantageously reaching 30 - 120 9 per m3 of H20 ~
.
.
The inven-tion concerns a process for ozonizing tap water, by the water electrolysis method and to equipment for ozonizing tap water using an ozone-generating electrolytic cell.
Ozonization is frequently used for the sterilisation of tap water. The conventional processes for this can be divided into the following part steps:
- Air preparation (drying) - Ozone generation by silent electric discharge - Contacting the tap water with the ozone-containing air stream (for example in a bubble column) - Removal of residual ozone, compare, for example C.M. Robson, "Design Engineering Aspects of Ozonation Systems", Handbook of Ozone Technology and Applications, R.G. Rice and A. Netzer, Editors, Volume 1, Ann Arbor, 1982.
The conventional processes as a rule require involved and expensive equipment, in parti-cular with respect to mixing of the tap water with the ozone-containing air.
It has been proposed in the past to generate ozone by electrolytic means, using highly pure water (compare H.-P. Klein and S. Stucki, "The Production of Ozone by Electrolysis and its Appli-cation in high-purity Water Systems", Conference Proceedings 7th Ozone World Congress, September ' . .
.~ ~
9-12, 1985, Tokyo; US-A-4,416,747).
The processes described above are less suitable for doping tap water with ozone, since large quantities must be handled and a considerable amount of apparatus is required. If the electrolytic process were used directly~ the cell would be blocked within a relatively short time by the divalent cations present in the tap water, so that its direct use would be uneconomical.
There is therefore a demand for improving and simplifying the known methods and equipment.
It is the object of the invention to pro-vide equipment and a process, by means of which tap water can be doped with ozone in a simple and economical manner and without great expense on apparatus.
In accordance with the invention there is provided a process for ozonizing tap water by a water electrolysis method using a solid electrolyte, characterized in tnat a freshwater stream is divided into a mainstream and a sidestream, in that the water of the sidestream is softened in a water-softening unit and is fed to an electrolytic cell and ozonized, and in that the resulting doped sidestream is com-bined with the mainstream in a mixer, the sidestreamamounting to 0.5 to 3% by volume of the rate of the freshwater stream and its ozone concentration down-stream of the electrolytic cell being 30-120 g per m3 of H2O.
From a different aspect, and in accordance with the invention, there is provided equipment for ozonizing tap water, using an ozone-generating electrolytic ceil provided with a solid electrolyte, which comprises an inlet line for the freshwater stream, a line for the mainstream and also a line for the sidestream in which there is a water-softening ,, ~
_ 3 _ ~3~
unit and, downstream of the latter, an e:Lectrolytic cell, and additionally a mixer at the point of con~
fluence of the main and side streams.
The invention is described by reference to the following illustrative example explained in more detail by a figure.
Figure 1 shows a flow chart of -the process and the diagrammatic structure of the equipment.
is the freshwater stream which is fed to the equip-ment and which, on entry, is divided into the main-stream 2 and the sidestream 3. 4 is a two-part water-softening unit which is connected to 3 via two isolation valves and the individual chambers (4) of which are operated alternately. The intermittent feed of NaCl as a regenerating salt is indicated by arrows. 5 represents an electrolytic cell which has a solid electrolyte and which dopes the desalinated sidestream 3 with ozone. The two streams 2 and 3 are combined again and intimately mixed in the mixer 6.
Illustrative Example:
A unit in accordance with the figure showed the ~ollowing operating parameters:
Tap water system pressure: 10 bar (freshwater stream) freshwater rate (1): 2 m3/h Water rate in mainstream (2); 1.97 m3/h Water rate in sidestream (3): 0.03 m3/h Operating current of the 03 cell (S): 40 A
Corresponding current density: 1.33 A/cm2 Electrode area of the 03 cell: 30 cm2 Cell voltage: 4.1 V
03 concentration downstream of cell (S): 60 g/m3 03 concentration downstream of mixer (6): 0.9 g/m3 . -. .
J
- 3a ~
As the water-softening unit 4, two cation exchanger columns were used, which were regenerated at intervals with an NaCl solution. This tandem operation allowed a continuous procedure. The side-stream 3 was passed from the water-softening unit 4 into the anode space of an electrolytic cell. The latter was provided with a solid electrolyte in the form of a perfluorinated ion exchanger membrane (trade mark "Nafion" from Du Pont). On either side of the membrane, there were porous electrodes which were pressed against each other under a surface pressure of 400 N/cm . The positive electrode (anode) consisted of a 1 mm thick porous titanium plate coated with PbO2, whereas the negative elect-rode (cathode) used was a porous composite of graphite and polytetrafluoroethylene. A thin plati-num Layer, acting as an electro-catalyst, was arranged between the cathode and the solid electrolyte.
When a direct current flows through the electrolytic cell, ,,,,~
-- ~3~
a mixture of oxygen and ozone is evolved at the anode.
The 2/3 ratio is on average 85% by weight to 15% by weight.
A probe for measuring the percentage quantity of ozone dissolved in the water of sidestream 3 was fitted immediately downstream of the electrolytic cell 5. In the mixer 6, the ozone-containing sidestream 3 was combined with the main-stream 2. The mixer 6 was designed as a static mixer.
The advantages of this process are that the water-softening unit 4 and the electrolytic cell 5 have to be sized only for the water rate of the sidestream 3 and that there is no poisoning of the electrolytic cell by divalent cations (above all calcium) present in the tap water.
Preferably, the fractional rate of the sidestream 3 can be 0.5 to 3% by volume of the rate of the freshwater stream 1, its ozone concentration downstream of the electrolytic cell 5 advantageously reaching 30 - 120 9 per m3 of H20 ~
.
.
Claims
1. Process for ozonizing tap water by a water electrolysis method using a solid electrolyte, characterized in that a freshwater stream is divided into a mainstream and a sidestream, in that the water of the sidestream is softened in a water-softening unit and is fed to an electrolytic cell and ozonized, and in that the resulting doped sidestream is combined with the mainstream in a mixer, the sidestream amounting to 0.5 to 3% by volume of the rate of the freshwater stream and its ozone concentration downstream of the electrolytic cell being 30-120 g per m3 of H2O.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CH99586A CH667867A5 (en) | 1986-03-11 | 1986-03-11 | METHOD AND DEVICE FOR LOADING TAP WATER WITH OZONE USING AN OZONE GENERATING ELECTROLYSIS CELL EQUIPPED WITH A SOLID ELECTROLYTE. |
| CH995/86-0 | 1986-03-11 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1315236C true CA1315236C (en) | 1993-03-30 |
Family
ID=4199996
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000531368A Expired - Fee Related CA1315236C (en) | 1986-03-11 | 1987-03-06 | Ozone-generating electrolytic cell provided with a solid electrolyte for treating water |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0244565B1 (en) |
| JP (1) | JPS62221490A (en) |
| CA (1) | CA1315236C (en) |
| CH (1) | CH667867A5 (en) |
| DE (1) | DE3762961D1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2006042373A1 (en) * | 2004-10-21 | 2006-04-27 | Ozone Manufacturing Pty Ltd | Potable water purifier for pressurised systems for buildings |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0813356B2 (en) * | 1988-09-29 | 1996-02-14 | ペルメレック電極株式会社 | Water treatment method and apparatus using electrolytic ozone |
| JPH0326389A (en) * | 1989-06-22 | 1991-02-04 | O D S:Kk | Active-oxygen reactor |
| JP3007137B2 (en) * | 1990-11-27 | 2000-02-07 | ペルメレック電極株式会社 | Electrolytic ozone generation method and apparatus |
| FR2698349B1 (en) * | 1992-11-24 | 1995-06-09 | Trailigaz | INSTALLATION FOR THE REMOVAL OF MICRO-POLLUTANTS FROM RAW WATER, PARTICULARLY DRILLING WATER, BY COMBINED ACTION OF OZONE AND HYDROGEN PEROXIDE. |
| JP3979671B2 (en) * | 1996-03-28 | 2007-09-19 | アレヴァ エンペー ゲゼルシャフト ミット ベシュレンクテル ハフツング | Gas injection device |
| US6171551B1 (en) * | 1998-02-06 | 2001-01-09 | Steris Corporation | Electrolytic synthesis of peracetic acid and other oxidants |
| EP1199931B1 (en) | 1999-08-05 | 2003-07-23 | Steris Inc. | Electrolytic synthesis of peracetic acid |
| JP2002263650A (en) * | 2001-03-14 | 2002-09-17 | Sanyo Electric Co Ltd | Method for generating ozone by electrolysis and ozone generating device |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4316787A (en) * | 1979-08-06 | 1982-02-23 | Themy Constantinos D | High voltage electrolytic cell |
| EP0068522B1 (en) * | 1981-05-11 | 1984-10-24 | BBC Aktiengesellschaft Brown, Boveri & Cie. | Process and apparatus for the synthetic preparation of ozone by electrolysis, and its application |
-
1986
- 1986-03-11 CH CH99586A patent/CH667867A5/en not_active IP Right Cessation
-
1987
- 1987-02-06 DE DE8787101607T patent/DE3762961D1/en not_active Expired - Lifetime
- 1987-02-06 EP EP19870101607 patent/EP0244565B1/en not_active Expired - Lifetime
- 1987-03-06 CA CA000531368A patent/CA1315236C/en not_active Expired - Fee Related
- 1987-03-11 JP JP5427187A patent/JPS62221490A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2006042373A1 (en) * | 2004-10-21 | 2006-04-27 | Ozone Manufacturing Pty Ltd | Potable water purifier for pressurised systems for buildings |
Also Published As
| Publication number | Publication date |
|---|---|
| CH667867A5 (en) | 1988-11-15 |
| EP0244565A1 (en) | 1987-11-11 |
| DE3762961D1 (en) | 1990-07-05 |
| JPS62221490A (en) | 1987-09-29 |
| EP0244565B1 (en) | 1990-05-30 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |