EP2162398A1 - Method of treating water - Google Patents

Method of treating water

Info

Publication number
EP2162398A1
EP2162398A1 EP20080761076 EP08761076A EP2162398A1 EP 2162398 A1 EP2162398 A1 EP 2162398A1 EP 20080761076 EP20080761076 EP 20080761076 EP 08761076 A EP08761076 A EP 08761076A EP 2162398 A1 EP2162398 A1 EP 2162398A1
Authority
EP
European Patent Office
Prior art keywords
carbon dioxide
membrane
water
flushing stream
added
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.)
Ceased
Application number
EP20080761076
Other languages
German (de)
French (fr)
Inventor
Berthold Müller
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Air Liquide Deutschland GmbH
Air Liquide SA
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Original Assignee
Air Liquide Deutschland GmbH
Air Liquide SA
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Air Liquide Deutschland GmbH, Air Liquide SA, LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude filed Critical Air Liquide Deutschland GmbH
Publication of EP2162398A1 publication Critical patent/EP2162398A1/en
Ceased legal-status Critical Current

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
    • C02F1/66—Treatment of water, waste water, or sewage by neutralisation; pH adjustment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D65/00—Accessories or auxiliary operations, in general, for separation processes or apparatus using semi-permeable membranes
    • B01D65/02—Membrane cleaning or sterilisation ; Membrane regeneration
    • 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
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/444—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by ultrafiltration or microfiltration
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F3/00—Biological treatment of water, waste water, or sewage
    • C02F3/02—Aerobic processes
    • C02F3/12—Activated sludge processes
    • C02F3/1236—Particular type of activated sludge installations
    • C02F3/1268—Membrane bioreactor systems
    • C02F3/1273—Submerged membrane bioreactors
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2315/00—Details relating to the membrane module operation
    • B01D2315/06—Submerged-type; Immersion type
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2321/00—Details relating to membrane cleaning, regeneration, sterilization or to the prevention of fouling
    • B01D2321/04—Backflushing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2321/00—Details relating to membrane cleaning, regeneration, sterilization or to the prevention of fouling
    • B01D2321/12—Use of permeate
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2321/00—Details relating to membrane cleaning, regeneration, sterilization or to the prevention of fouling
    • B01D2321/18—Use of gases
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2209/00—Controlling or monitoring parameters in water treatment
    • C02F2209/02—Temperature
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2209/00—Controlling or monitoring parameters in water treatment
    • C02F2209/03—Pressure
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2209/00—Controlling or monitoring parameters in water treatment
    • C02F2209/40—Liquid flow rate
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2303/00—Specific treatment goals
    • C02F2303/16—Regeneration of sorbents, filters
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W10/00—Technologies for wastewater treatment
    • Y02W10/10—Biological treatment of water, waste water, or sewage

Definitions

  • the present invention relates to a method of treating water, in particular treating wastewater.
  • the method according to the invention is concerned with membrane filtration in biological wastewater purification.
  • membrane filtration is widely used in water and wastewater treatment.
  • membrane filtration methods are used for activated sludge removal after biological treatment of the wastewaters.
  • backwashes are provided at relatively short intervals. This is necessary, since in particular in biological wastewater treatment, the corresponding membranes become plugged by coat formations.
  • the compressed air additionally accelerates the formation of lime on the membrane by stripping out carbon dioxide. This is taken to mean shifting the solution equilibrium by adding compressed air which leads to carbon dioxide which is dissolved in the water outgassing. If the membrane is blocked too severely, it must be removed and supplied to a physicochemical cleaning. This is cost-intensive and causes relatively long down times of the corresponding membrane.
  • the object of the present invention is to propose a method for treating water which at least mitigates the above-described disadvantages.
  • This object is achieved by a method having the features of the independent claim.
  • the dependent claims are directed towards advantageous developments.
  • the method according to the invention of treating water in which water is separated from a retentate by means of filtration through at least one membrane, wherein the water, on filtration, flows through the membrane in a permeation direction, wherein at least one membrane is, at least at times, flushed by a flushing stream in a direction essentially opposite to a permeation direction, is characterized in that gaseous carbon dioxide (CO2) is added to the flushing stream.
  • CO2 gaseous carbon dioxide
  • the carbonic acid is in reaction equilibrium with lime, in particular calcium carbonate and calcium hydrogen- carbonate :
  • the flushing stream comprises water (H 2 O) .
  • Water advantageously implements good cleaning of the corresponding membranes, it is available at low cost and has a high solubility for carbon dioxide. By using water as flushing stream, good cleaning of the membrane can thus be achieved with inexpensive simple means.
  • the proportion of gaseous carbon dioxide is above the saturation limit for carbon dioxide.
  • the saturation limit is taken to mean an equilibrium concentration of carbon dioxide in water at which a diffusion equilibrium prevails between carbon dioxide molecules entering into solution and leaving the solution. This saturation limit is dependent on the pressure and temperature of the flushing water.
  • gas bubbles can form in the flushing stream which advantageously increase the cleaning action within the membrane. This occurs, for example, by turbulence being generated or increased in the membrane by the carbon dioxide gas bubbles.
  • the carbon dioxide is added in such a manner that gas bubbles form which can also still penetrate into relatively small pores of the membrane.
  • carbon dioxide is added in - A - such a manner that carbon dioxide bubbles of a diameter from one micrometer to three millimetres are formed.
  • carbon dioxide is added in such a manner that carbon dioxide bubbles having a median diameter of 100 to 800 micrometers are formed.
  • Such a median diameter has the effect that the gaseous carbon dioxide can also penetrate into pores of small diameter and can there increase the cleaning action.
  • carbon dioxide is added in such a manner that the width of the distribution (FWHM, full width at half maximum) of the bubble diameter is less than 1 millimetre.
  • This width of the distribution advantageously makes possible a thorough cleaning of the various pores of the membranes which are used in wastewater treatment.
  • the carbon dioxide is added in such a manner that a size distribution is achieved which essentially corresponds to the size distribution of the pores to be cleaned.
  • the proportion of gaseous carbon dioxide is below the saturation limit for carbon dioxide.
  • the amount of carbon dioxide to be added is established as a function of at least one of the following parameters: a) a flow rate of the flushing stream and b) a temperature of the flushing stream.
  • an amount of carbon dioxide is determined which increases with increasing flow rate and decreases with increasing temperature.
  • Preference here is given to a method procedure in which the reaction equilibrium is essentially on the side of calcium hydrogencarbonate .
  • a time interval between two successive flushings of the membrane by the flushing stream is established as a function of the pressure drop of the membrane.
  • the pressure drop has proved to be a good index of the corresponding filtering action of the membrane. With increasing pressure drop and after exceeding a presettable threshold pressure drop, it can be assumed that the filtering action of the membrane is restricted. Then, backwashing of the membrane is initiated.
  • Fig. 1 a membrane filtration system for wastewater purification for illustration of the method according to the invention
  • Fig. 2 an example of a distribution of the bubble diameters .
  • the wastewater treatment system 1 comprises at least one membrane unit 2 having a multiplicity of membranes 3. Via a feed 4, the wastewater treatment system 1 is supplied with wastewater 5 to be treated. In the wastewater treatment system 1, in particular biological wastewater treatment with activated sludge is performed. By applying a reduced pressure to the outlet line 6, filtration is carried out in which the water in the wastewater 5 flows through the membranes 3 in a permeation direction, here from outside to inside. The filtrate 7 thus produced is taken off by the outlet line 6.
  • a flushing stream 8 can be introduced into the membranes 3 in such a manner that this flushing stream 8 flows through them in the opposite direction to the permeation direction.
  • gaseous carbon dioxide 10 can be added in a manner according to the invention to the flushing stream 8.
  • the gaseous carbon dioxide prevents the formation of calcium carbonate in the membrane or dissolves calcium carbonate present there by utilizing the above- described reaction with carbonic acid to form calcium hydrogencarbonate .
  • the carbon dioxide stream is of such a size that carbon dioxide is present oversaturated in the flushing stream 8. This leads to the formation of carbon dioxide bubbles which cause an increase in turbulence of the flow through the membranes 3 and an increased cleaning action in the membranes 3.
  • Fig. 2 shows an example of a distribution 11 of the bubble diameters.
  • the probability P(D) of a defined bubble diameter D is plotted against the bubble diameter.
  • Probability P(D) and bubble diameter D are reported in arbitrary units.
  • the distribution 11 has a median diameter 12 and a width 13 (FWHM, full width at half maximum) .
  • the integral under the distribution 11 is 1.
  • the method according to the invention advantageously permits the cleaning of membranes 3, for example in wastewater treatment systems 1, which, for example, carry out activated sludge separation.
  • the intervals between two backwashing processes can be significantly increased. This increases the profitability of the corresponding systems, since the operating times of the corresponding wastewater treatment systems 1 are increased and the intervals between backwashing processes and physicochemical cleaning of the membranes 3 are decreased.

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Organic Chemistry (AREA)
  • Biodiversity & Conservation Biology (AREA)
  • Microbiology (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)

Abstract

The method according to the invention of treating water in which water is separated from a retentate by means of filtration through at least one membrane (3), wherein the water, on filtration, flows through the membrane (3) in a permeation direction, wherein at least one membrane (3) is, at least at times, flushed by a flushing stream (8) in a direction essentially opposite to a permeation direction, is characterized in that gaseous carbon dioxide (CO2) is added to the flushing stream (8). The method according to the invention advantageously permits the cleaning of membranes (3), for example in wastewater treatment systems (1), which, for example, carry out activated sludge separation. By means of the method according to the invention, the intervals between two backwashing processes can be significantly increased. This increases the profitability of the corresponding systems, since the operating times of the corresponding wastewater treatment systems (1) are increased and the intervals between backwashing processes and physicochemical cleaning of the membranes (3) are decreased.

Description

Method of treating water
The present invention relates to a method of treating water, in particular treating wastewater. In particular, the method according to the invention is concerned with membrane filtration in biological wastewater purification.
The method of membrane filtration is widely used in water and wastewater treatment. Inter alia, in biological wastewater treatment, membrane filtration methods are used for activated sludge removal after biological treatment of the wastewaters. In order that the membranes do not block, backwashes are provided at relatively short intervals. This is necessary, since in particular in biological wastewater treatment, the corresponding membranes become plugged by coat formations. Despite vigorous turbulence which is generated around the membrane, in which, for example, compressed air is added, within a short time deposits on the membrane surface occur. The compressed air additionally accelerates the formation of lime on the membrane by stripping out carbon dioxide. This is taken to mean shifting the solution equilibrium by adding compressed air which leads to carbon dioxide which is dissolved in the water outgassing. If the membrane is blocked too severely, it must be removed and supplied to a physicochemical cleaning. This is cost-intensive and causes relatively long down times of the corresponding membrane.
Proceeding herefrom, the object of the present invention is to propose a method for treating water which at least mitigates the above-described disadvantages. This object is achieved by a method having the features of the independent claim. The dependent claims are directed towards advantageous developments.
The method according to the invention of treating water in which water is separated from a retentate by means of filtration through at least one membrane, wherein the water, on filtration, flows through the membrane in a permeation direction, wherein at least one membrane is, at least at times, flushed by a flushing stream in a direction essentially opposite to a permeation direction, is characterized in that gaseous carbon dioxide (CO2) is added to the flushing stream.
As a result of adding the carbon dioxide, carbonic acid forms in water:
CO2 + H2O → H2CO3.
The carbonic acid is in reaction equilibrium with lime, in particular calcium carbonate and calcium hydrogen- carbonate :
CaCO3 + H2CO3 <→ Ca(HCO3)2.
In this case calcium carbonate precipitates out as solid, whereas calcium hydrogencarbonate is still in solution. By increasing the carbonic acid proportion, the reaction equilibrium can thereby be shifted towards calcium hydrogencarbonate. This effectively prevents the precipitation of lime. As a result the blocking of the corresponding membrane is retarded, in such a manner that here a longer service life and operating time of the membrane can be achieved. In addition, on backwashing, lime already precipitated out on the membrane can be redissolved as calcium hydrogencarbonate. This causes a cleaning of the membranes and dissolution of the coatings already forming there.
According to an advantageous embodiment of the method according to the invention, the flushing stream comprises water (H2O) .
Water advantageously implements good cleaning of the corresponding membranes, it is available at low cost and has a high solubility for carbon dioxide. By using water as flushing stream, good cleaning of the membrane can thus be achieved with inexpensive simple means.
According to a further advantageous embodiment of the method according to the invention, the proportion of gaseous carbon dioxide is above the saturation limit for carbon dioxide.
In this case the saturation limit is taken to mean an equilibrium concentration of carbon dioxide in water at which a diffusion equilibrium prevails between carbon dioxide molecules entering into solution and leaving the solution. This saturation limit is dependent on the pressure and temperature of the flushing water.
By the proportion of gaseous carbon dioxide being above the saturation limit for carbon dioxide, gas bubbles can form in the flushing stream which advantageously increase the cleaning action within the membrane. This occurs, for example, by turbulence being generated or increased in the membrane by the carbon dioxide gas bubbles. Preferably, in this case, the carbon dioxide is added in such a manner that gas bubbles form which can also still penetrate into relatively small pores of the membrane.
According to a further advantageous embodiment of the method of the invention, carbon dioxide is added in - A - such a manner that carbon dioxide bubbles of a diameter from one micrometer to three millimetres are formed. Preferably, carbon dioxide is added in such a manner that carbon dioxide bubbles having a median diameter of 100 to 800 micrometers are formed.
Such a median diameter has the effect that the gaseous carbon dioxide can also penetrate into pores of small diameter and can there increase the cleaning action. The carbon dioxide present not in gas form, but dissolved, also increases the cleaning action in the membranes .
According to a further advantageous embodiment of the method according to the invention, carbon dioxide is added in such a manner that the width of the distribution (FWHM, full width at half maximum) of the bubble diameter is less than 1 millimetre.
This width of the distribution advantageously makes possible a thorough cleaning of the various pores of the membranes which are used in wastewater treatment. Preferably, in this case, the carbon dioxide is added in such a manner that a size distribution is achieved which essentially corresponds to the size distribution of the pores to be cleaned.
According to a further advantageous embodiment of the process according to the invention, the proportion of gaseous carbon dioxide is below the saturation limit for carbon dioxide.
This has the effect that no gaseous carbon dioxide, but only dissolved carbon dioxide, is present in the flushing stream. Dissolved carbon dioxide causes an enrichment of the water in the neighbourhood of the membrane to be cleaned with carbon dioxide, as a result of which the formation of lime by reaction with atmospheric oxygen is delayed. This delays lime precipitates and shifts the corresponding reaction equilibrium in such a manner that already formed lime precipitates regress again.
According to a further advantageous embodiment of the method according to the invention, the amount of carbon dioxide to be added is established as a function of at least one of the following parameters: a) a flow rate of the flushing stream and b) a temperature of the flushing stream.
In this case, preferably an amount of carbon dioxide is determined which increases with increasing flow rate and decreases with increasing temperature. Preference here is given to a method procedure in which the reaction equilibrium is essentially on the side of calcium hydrogencarbonate .
According to a further advantageous embodiment of the method according to the invention, a time interval between two successive flushings of the membrane by the flushing stream is established as a function of the pressure drop of the membrane.
The pressure drop has proved to be a good index of the corresponding filtering action of the membrane. With increasing pressure drop and after exceeding a presettable threshold pressure drop, it can be assumed that the filtering action of the membrane is restricted. Then, backwashing of the membrane is initiated.
Hereinafter, the invention will be described in more detail on the basis of the accompanying drawings, without restricting it to the details disclosed there. In the drawings there are shown diagrammatically : Fig. 1 a membrane filtration system for wastewater purification for illustration of the method according to the invention and
Fig. 2 an example of a distribution of the bubble diameters .
The wastewater treatment system 1 comprises at least one membrane unit 2 having a multiplicity of membranes 3. Via a feed 4, the wastewater treatment system 1 is supplied with wastewater 5 to be treated. In the wastewater treatment system 1, in particular biological wastewater treatment with activated sludge is performed. By applying a reduced pressure to the outlet line 6, filtration is carried out in which the water in the wastewater 5 flows through the membranes 3 in a permeation direction, here from outside to inside. The filtrate 7 thus produced is taken off by the outlet line 6.
If, for example, because of coating formation in or on the pores of the membranes 3 backwashing is necessary, by corresponding means such as, for example, a pump, a flushing stream 8 can be introduced into the membranes 3 in such a manner that this flushing stream 8 flows through them in the opposite direction to the permeation direction. Via a valve 9, in this case, gaseous carbon dioxide 10 can be added in a manner according to the invention to the flushing stream 8. The gaseous carbon dioxide prevents the formation of calcium carbonate in the membrane or dissolves calcium carbonate present there by utilizing the above- described reaction with carbonic acid to form calcium hydrogencarbonate . In this case, preferably, the carbon dioxide stream is of such a size that carbon dioxide is present oversaturated in the flushing stream 8. This leads to the formation of carbon dioxide bubbles which cause an increase in turbulence of the flow through the membranes 3 and an increased cleaning action in the membranes 3.
Fig. 2 shows an example of a distribution 11 of the bubble diameters. In this case, the probability P(D) of a defined bubble diameter D is plotted against the bubble diameter. Probability P(D) and bubble diameter D are reported in arbitrary units. The distribution 11 has a median diameter 12 and a width 13 (FWHM, full width at half maximum) . The integral under the distribution 11 is 1.
The method according to the invention advantageously permits the cleaning of membranes 3, for example in wastewater treatment systems 1, which, for example, carry out activated sludge separation. By the method according to the invention, the intervals between two backwashing processes can be significantly increased. This increases the profitability of the corresponding systems, since the operating times of the corresponding wastewater treatment systems 1 are increased and the intervals between backwashing processes and physicochemical cleaning of the membranes 3 are decreased.
List of reference signs
1 Wastewater treatment system
2 Membrane unit
3 Membrane
4 Feed
5 Wastewater
6 Outlet line
7 Filtrate
8 Flushing stream
9 Valve
10 Carbon dioxide
11 Distribution
12 Median diameter
13 Width

Claims

Claims
1. Method of treating water in which water is separated from a retentate by means of filtration through at least one membrane (3) , wherein the water, on filtration, flows through the membrane
(3) in a permeation direction, wherein at least one membrane (3) is, at least at times, flushed by a flushing stream (8) in a direction essentially opposite to a permeation direction, characterized in that gaseous carbon dioxide (CO2) is added to the flushing stream (8) .
2. Method according to Claim 1 in which the flushing stream (8) comprises water.
3. Method according to Claim 1 or 2, in which the proportion of gaseous carbon dioxide is above the saturation limit for carbon dioxide.
4. Method according to Claim 3, in which carbon dioxide is added in such a manner that carbon dioxide bubbles of a diameter from 1 micrometer to 3 millimetres are formed.
5. Method according to Claim 4, in which carbon dioxide is added in such a manner that the width
(13) of the distribution (11) (FWHM, full width at half maximum) of the bubble diameters is less than 1 millimetre.
6. Method according to Claim 1 or 2, in which the proportion of gaseous carbon dioxide is below the saturation limit for carbon dioxide.
7. Method according to one of the preceding claims, in which the amount of carbon dioxide to be added is established as a function of at least one of the following parameters: a) a flow rate of the flushing stream and b) a temperature of the flushing stream.
8. Process according to one of the preceding claims, in which a time interval between two successive flushings of the membrane (3) by the flushing stream (8) is established as a function of the pressure drop of the membrane (3) .
EP20080761076 2007-06-28 2008-06-16 Method of treating water Ceased EP2162398A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE200710030105 DE102007030105A1 (en) 2007-06-28 2007-06-28 Process for the treatment of water
PCT/EP2008/057569 WO2009000693A1 (en) 2007-06-28 2008-06-16 Method of treating water

Publications (1)

Publication Number Publication Date
EP2162398A1 true EP2162398A1 (en) 2010-03-17

Family

ID=39643194

Family Applications (1)

Application Number Title Priority Date Filing Date
EP20080761076 Ceased EP2162398A1 (en) 2007-06-28 2008-06-16 Method of treating water

Country Status (3)

Country Link
EP (1) EP2162398A1 (en)
DE (1) DE102007030105A1 (en)
WO (1) WO2009000693A1 (en)

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS57190605A (en) * 1981-05-18 1982-11-24 Hitachi Plant Eng & Constr Co Ltd Method for washing membrane of separation apparatus
JPS6287205A (en) * 1985-10-14 1987-04-21 Hitachi Ltd How to clean hollow fiber membrane filters
JPS63147506A (en) * 1986-12-12 1988-06-20 Hitachi Ltd How to clean hollow fiber membrane filters
JPS63171605A (en) * 1987-01-09 1988-07-15 Hitachi Ltd Carbon dioxide cleaning method for hollow fiber membrane filters
JPS63302910A (en) * 1987-05-30 1988-12-09 Nippon Atom Ind Group Co Ltd Method for washing porous filter
JPH04271819A (en) * 1991-02-27 1992-09-28 Fuji Photo Film Co Ltd Method for regeneration of filter membrane
JPH06194296A (en) * 1992-12-25 1994-07-15 Meidensha Corp Method for measuring ozone bubble diameter in ozone contact tank
DE19623999C2 (en) * 1996-06-15 2000-12-07 Letzner Hans Hermann Method and device for treating cold water
DE19734759C1 (en) * 1997-08-10 1998-08-27 Chmiel Horst Waste water treatment and assembly
US20040129637A1 (en) * 2000-07-07 2004-07-08 Hidayat Husain Multi-stage filtration and softening module and reduced scaling operation
JP2003010651A (en) * 2001-07-03 2003-01-14 Sumitomo Heavy Ind Ltd Method for backward washing of filter

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2009000693A1 *

Also Published As

Publication number Publication date
DE102007030105A1 (en) 2009-01-02
WO2009000693A1 (en) 2008-12-31

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