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WO2018193907A1 - Procédé de traitement d'eau - Google Patents

Procédé de traitement d'eau Download PDF

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Publication number
WO2018193907A1
WO2018193907A1 PCT/JP2018/015019 JP2018015019W WO2018193907A1 WO 2018193907 A1 WO2018193907 A1 WO 2018193907A1 JP 2018015019 W JP2018015019 W JP 2018015019W WO 2018193907 A1 WO2018193907 A1 WO 2018193907A1
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WO
WIPO (PCT)
Prior art keywords
chlorine
water
water treatment
treatment method
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
PCT/JP2018/015019
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English (en)
Japanese (ja)
Inventor
勝郎 依田
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.)
Kurita Water Industries Ltd
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Kurita Water Industries Ltd
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 Kurita Water Industries Ltd filed Critical Kurita Water Industries Ltd
Publication of WO2018193907A1 publication Critical patent/WO2018193907A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
    • B01D61/04—Feed pretreatment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
    • B01D61/12—Controlling or regulating
    • 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
    • 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
    • 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
    • C02F1/50—Treatment of water, waste water, or sewage by addition or application of a germicide or by oligodynamic treatment

Definitions

  • the present invention relates to a water treatment method, and more particularly to a water treatment method for suppressing biofouling in a water treatment device such as a reverse osmosis membrane (RO membrane) device for seawater desalination.
  • a water treatment device such as a reverse osmosis membrane (RO membrane) device for seawater desalination.
  • RO membrane reverse osmosis membrane
  • RO membrane devices are widely used as means for producing pure water by treating industrial water, city water, well water, sea water, river water, lake water, factory waste water, and the like.
  • chlorine-based oxidizing agents such as chlorine, sodium hypochlorite, and sodium chlorite are added to the treated water (feed water) in order to suppress biofouling by microorganisms contained in the treated water. To do.
  • chlorine is also generated by electrolysis.
  • RO membrane When water containing free chlorine is added by the addition of chlorinated oxidant or electrolysis, the RO membrane undergoes oxidative degradation.
  • polyamide-based RO membranes are susceptible to oxidative degradation.
  • an activated carbon tower is installed at the front stage of the RO membrane apparatus to remove residual oxidants such as chlorine (Patent Document 1), or a reducing agent such as sodium bisulfite (SBS) or sodium sulfite is installed at the front stage of the RO membrane apparatus. Addition to decompose and remove chlorine (Patent Document 2).
  • FIGS. 2a and 2b are system diagrams showing an example of a conventional seawater desalination facility.
  • a chlorine-based oxidant such as sodium hypochlorite (NaClO) is added in the process of supplying seawater to the raw water tank 1 by a water pump.
  • an inorganic flocculant such as ferric chloride (FeCl 3 ) is added in the course of being fed from the raw water tank 1 to the reaction tank 2, and agglomeration treatment is performed in the reaction tank 2.
  • the RO membrane treatment is performed by the RO membrane device 6 through the water supply tank 4 and the security filter 5.
  • RO membrane permeated water is taken out as treated water.
  • a reducing agent such as sodium bisulfite (SBS) is added to decompose and remove the residual oxidant.
  • seawater is electrolyzed by the electrolyzer 7, and seawater containing chlorine generated by electrolysis is aggregated and filtered in the same manner as in FIG. 2a, and then a reducing agent such as SBS is added. And processed by the RO membrane device 6.
  • a control agent for example, “Kuriverter IK-110” manufactured by Kurita Kogyo Co., Ltd.
  • Kurita Kogyo Co., Ltd. may be added.
  • the conventional seawater desalination RO membrane treatment has the following problems.
  • Free chlorine produced by the addition of a chlorine-based oxidant such as sodium hypochlorite or the electrolysis of seawater is easily decomposed by organic substances, bromine and iodine in the seawater.
  • organic substances bromine and iodine in the seawater.
  • a chlorine-based oxidant is added to seawater, harmful organic chlorine compounds such as trihalomethane are produced, which is problematic for drinking water applications.
  • (3) In order to prevent oxidative degradation of the RO membrane it is necessary to add a reducing agent or install an activated carbon tower on the RO membrane inlet side, and the treatment is complicated.
  • This invention aims at providing the water treatment method which solves the subject of the above-mentioned conventional method.
  • the present inventor Prior to the generation of chlorine by addition of a chlorine-based oxidant or electrolysis, the present inventor added a nitrogen compound as a chlorine stabilizer to the feed water to stabilize the chlorine in the feed water.
  • a nitrogen compound as a chlorine stabilizer
  • biofouling of the RO membrane can be effectively suppressed.
  • the gist of the present invention is as follows.
  • a water treatment method for supplying free water to a water treatment apparatus after adding free chlorine by adding a chlorine-based oxidant to the water supplied to the water treatment apparatus or generating chlorine by electrolysis,
  • a water treatment method characterized by adding a nitrogen compound as a chlorine stabilizer to the feed water prior to the presence of free chlorine in the feed water.
  • a nitrogen compound is added to the feed water as a chlorine stabilizer, and then the free chlorine added or generated in the feed water is stabilized.
  • the presence of chlorine as stabilized chlorine in the feed water and the reduction of free chlorine concentration reduces the RO membrane oxidation degradation of the feed water, so the addition of a reducing agent on the RO membrane inlet side and the activated carbon tower The installation of can be made unnecessary. As a result, the process can be simplified, and biofouling in the RO membrane device can be effectively suppressed by the stabilized chlorine.
  • 1a and 1b are system diagrams of a seawater desalination facility showing an example of an embodiment of a water treatment method of the present invention.
  • 2a and 2b are system diagrams of a conventional seawater desalination facility.
  • 6 is a graph showing the results of Experimental Example 1.
  • 10 is a graph showing the results of Experimental Example 2.
  • 10 is a graph showing the results of Experimental Example 3.
  • 10 is a graph showing the results of Experimental Example 4.
  • 10 is a graph showing the results of Experimental Example 5.
  • 10 is a graph showing the results of Experimental Example 6.
  • 6 is a graph showing the results of Comparative Experimental Example 1.
  • FIGS. 1a and 1b are system diagrams showing an example of seawater desalination equipment to which the water treatment method of the present invention is applied, and are the same as members having the same functions as the seawater desalination equipment shown in FIGS. 2a and 2b, respectively.
  • symbol is attached
  • a nitrogen compound is added to the feed water as a chlorine stabilizer prior to the addition of a chlorine-based oxidizing agent such as sodium hypochlorite (NaClO) or the generation of chlorine by electrolysis. Add to stabilize chlorine in the feed water.
  • a chlorine-based oxidizing agent such as sodium hypochlorite (NaClO) or the generation of chlorine by electrolysis.
  • the nitrogen compound added for stabilizing the chlorine is not particularly limited as long as it can stabilize the chlorine in the supply water as stabilized bound chlorine or activated bound chlorine.
  • nitrogen compounds include sulfamic acid, sulfamic acid sodium salts, potassium salts, calcium salts, ammonium salts, and other sulfamic acid compounds, glycine, taurine, threonine, ornithine (L-ornithine), alanine, phenylalanine (L-phenylalanine), and the like.
  • Organic nitrogen compounds are mentioned. Only 1 type may be used for a nitrogen compound and it may use 2 or more types together.
  • the amount of nitrogen compound added to the feed water depends on the type of nitrogen compound used, the amount of chlorinated oxidant added in the subsequent stage, the amount of chlorine generated by electrolysis, the chlorine concentration to be maintained in the feed water, etc. However, it is preferably 0.3 to 50 mg / L, particularly about 0.3 to 20 mg / L. If the amount of nitrogen compound added is too small, the chlorine in the feed water cannot be sufficiently stabilized. Even if the amount of the nitrogen compound added is too large, the processing cost becomes high or it causes fouling and is inappropriate.
  • a nitrogen compound as a chlorine stabilizer is added at the above-mentioned preferable addition amount, and after the nitrogen compound is sufficiently uniformly diffused in the feed water, a chlorine-based oxidant is added or electrolysis is performed. It is preferable to generate chlorine.
  • a chlorine-based oxidizer as shown in FIG. 1a
  • a nitrogen compound as a chlorine stabilizer is added on the discharge side of the water pump and is homogenized while staying in the raw water tank 1.
  • a chlorine-based oxidizing agent such as NaClO together with an inorganic flocculant such as FeCl 3 at the outlet side of the raw water tank 1.
  • electrolysis as shown in FIG. 1b, it is preferable to add a chlorine stabilizer on the discharge side of the water pump to make it uniform during electrolysis in the electrolyzer 7 and to generate chlorine.
  • any conventionally known one can be used as the chlorine-based oxidant.
  • the chlorinated oxidant from the viewpoint of product safety, hypochlorite such as sodium hypochlorite or dichloroisocyanurate such as dichloroisocyanuric acid and sodium dichloroisocyanurate is preferable. It is preferable to use sodium chlorate or dichloroisocyanuric acid. Only one type of chlorine-based oxidizing agent may be used, or two or more types may be used in combination.
  • the addition amount of the chlorine-based oxidant varies depending on the tendency of biofouling to occur in the water system to be treated, but is usually about 0.1 to 1.0 mg / L, particularly about 0.3 to 0.7 mg / L. preferable.
  • the residual chlorine concentration at the inlet of the RO membrane device is 0.3 to 1.0 mg-Cl 2 / L, particularly 0.5. It is preferable to control it to be about 0.7 mg-Cl 2 / L. If the residual chlorine concentration at the RO membrane device inlet is lower than the lower limit, a sufficient biofouling suppression effect may not be obtained. If the residual chlorine concentration at the RO membrane device inlet exceeds the above upper limit, there is a risk of RO membrane deterioration, depending on the proportion of free chlorine in the residual chlorine.
  • the residual chlorine concentration at the RO membrane apparatus inlet is in the above range by stabilizing chlorine by a chlorine-based oxidizing agent or chlorine generated by electrolysis with a nitrogen compound, and the free chlorine concentration is 0.1.
  • the free chlorine concentration is 0.1.
  • the proportion of bonded chlorine (total of activated bonded chlorine and stabilized bonded chlorine) in the residual chlorine at the entrance of the RO membrane device is preferably 90% or more, and more preferably 80% or more of stabilized bonded chlorine. It is preferable that By controlling the type and addition amount of the nitrogen compound as the chlorine stabilizer so as to be such a ratio, it is possible to obtain a favorable biofouling suppressing effect while preventing the RO membrane from being deteriorated.
  • Free chlorine, activated bound chlorine, and stabilized bound chlorine correspond to chlorine measured by the method described in the Examples section below. Residual chlorine is the sum of these free chlorine, activated bound chlorine and stabilized bound chlorine.
  • the water treatment apparatus is not limited to the RO membrane apparatus, and a chlorine-based oxidizing agent is used to suppress biofouling.
  • a water treatment device such as an ion exchange device in which free chlorine needs to be removed on the inlet side in order to prevent deterioration of the device.
  • Supply water is not limited to seawater, but can also be applied to river water, well water, lake water, various types of drainage, or the like.
  • the effect of the present invention is particularly effectively exhibited when applied to a desalination facility using a seawater RO membrane device.
  • the chlorine concentration (mg-Cl 2 / L) was measured using a pocket chlorine measuring device “HACH2470” manufactured by Toa DKK, and each chlorine concentration was determined by the following measurement method or calculation method.
  • Free chlorine concentration Chlorine concentration measurement result (mg-Cl 2 / L) after 5 to 30 seconds with DPD (Free) reagent, which is a reagent for measuring free chlorine
  • Activated bound chlorine concentration From the chlorine concentration measurement result (mg-Cl 2 / L) after 300 seconds by the DPD (Free) reagent, which is a reagent for measuring free chlorine, the above-mentioned free chlorine concentration (mg-Cl 2 / L) Value obtained by subtracting measurement results
  • Stabilized bound chlorine concentration Reagent for free chlorine measurement from the chlorine concentration measurement result (mg-Cl 2 / L) after 180 seconds using DPD (Total) reagent which is a reagent for total chlorine measurement The value obtained by subtracting the chlorine concentration measurement result (mg-Cl 2 / L) after 300 seconds using the DPD (Free) reagent.
  • Residual chlorine concentration Sum of the above free chlorine concentration, activated bound chlorine concentration and stabilized bound chlorine concentration (mg -Cl 2 /
  • Example 2 Glycine
  • Example 3 Phenylalanine
  • Example 4 Threonine
  • Example 5 Ornithine
  • Example 6 Taurine
  • a chlorine-based oxidant such as sodium hypochlorite is added or free chlorine is generated by electrolysis, whereby chlorine in the supply water is reduced. It can be stabilized, and the following excellent effects can be obtained. 1) Since the decomposition and consumption of chlorine by organic matter, bromine and iodine in seawater can be suppressed, the amount of chlorinated oxidant added necessary to suppress biofouling is reduced or the power consumption of the electrolyzer is reduced. be able to. 2) By reducing the free chlorine concentration, it is possible to reduce the influence of RO membrane deterioration and the like.
  • biofouling of the RO membrane can be suppressed without performing decomposition treatment with a reducing agent or activated carbon tower before the RO membrane device. 3) By stabilizing chlorine, it is possible to suppress the generation of harmful substances such as trihalomethanes.
  • the effect of the present invention cannot be obtained by the post-addition of the nitrogen compound, the effect of the present invention is that the chlorine-based oxidant is simply stabilized with the nitrogen compound and added as a combined chlorine-based oxidant. It turns out that it is completely different.

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  • Chemical & Material Sciences (AREA)
  • Water Supply & Treatment (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Organic Chemistry (AREA)
  • Environmental & Geological Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Nanotechnology (AREA)
  • Hydrology & Water Resources (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Treatment Of Water By Oxidation Or Reduction (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)

Abstract

L'invention concerne un procédé de traitement d'eau dans lequel, après avoir amené du chlore libre dans de l'eau destinée à être alimentée à un dispositif de traitement d'eau par production de chlore par l'addition d'un agent oxydant au chlore ou par électrolyse, le dispositif de traitement d'eau est alimenté en eau, ledit procédé ajoutant un composé azoté à l'eau destinée à être alimentée, en tant qu'agent de stabilisation de chlore avant avant d'amener le chlore libre dans l'eau destinée à être alimentée.
PCT/JP2018/015019 2017-04-19 2018-04-10 Procédé de traitement d'eau Ceased WO2018193907A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2017-082942 2017-04-19
JP2017082942A JP6565966B2 (ja) 2017-04-19 2017-04-19 水処理方法

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WO2018193907A1 true WO2018193907A1 (fr) 2018-10-25

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WO (1) WO2018193907A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US12221360B2 (en) 2021-09-24 2025-02-11 Bechtel Energy Technologies & Solutions, Inc. Low energy ejector desalination system

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP7243746B2 (ja) * 2021-01-20 2023-03-22 栗田工業株式会社 膜分離方法

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JP2006022097A (ja) * 2004-07-02 2006-01-26 Rohm & Haas Co 殺菌組成物
JP2006289298A (ja) * 2005-04-13 2006-10-26 Ase:Kk 水処理方法および水処理装置
WO2012133620A1 (fr) * 2011-03-30 2012-10-04 栗田工業株式会社 Procédé de séparation par membrane
JP2015063475A (ja) * 2013-09-24 2015-04-09 栗田工業株式会社 冷却水系の抗菌・殺藻方法および抗菌・殺藻剤
JP2016120457A (ja) * 2014-12-25 2016-07-07 オルガノ株式会社 ろ過処理システムおよびろ過処理方法
JP2016120466A (ja) * 2014-12-25 2016-07-07 オルガノ株式会社 ろ過処理システムおよびろ過処理方法
WO2016158633A1 (fr) * 2015-03-31 2016-10-06 栗田工業株式会社 Procédé de fonctionnement de système de traitement sur membrane d'osmose inverse et système de traitement sur membrane d'osmose inverse

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JPH07124559A (ja) * 1993-11-08 1995-05-16 Toyobo Co Ltd 海水淡水化プロセスにおける被処理水の殺菌方法
US8388990B2 (en) * 2002-10-07 2013-03-05 Ecolab Usa Inc. Acidified chlorite compositions containing nitrogenous stabilizers and systems and methods related thereto
US9206058B2 (en) * 2009-02-20 2015-12-08 The Water Initative, Llc Water purification and enhancement systems
JP6340566B2 (ja) * 2013-09-19 2018-06-13 三菱瓦斯化学株式会社 海生生物の付着防止方法

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006022097A (ja) * 2004-07-02 2006-01-26 Rohm & Haas Co 殺菌組成物
JP2006289298A (ja) * 2005-04-13 2006-10-26 Ase:Kk 水処理方法および水処理装置
WO2012133620A1 (fr) * 2011-03-30 2012-10-04 栗田工業株式会社 Procédé de séparation par membrane
JP2015063475A (ja) * 2013-09-24 2015-04-09 栗田工業株式会社 冷却水系の抗菌・殺藻方法および抗菌・殺藻剤
JP2016120457A (ja) * 2014-12-25 2016-07-07 オルガノ株式会社 ろ過処理システムおよびろ過処理方法
JP2016120466A (ja) * 2014-12-25 2016-07-07 オルガノ株式会社 ろ過処理システムおよびろ過処理方法
WO2016158633A1 (fr) * 2015-03-31 2016-10-06 栗田工業株式会社 Procédé de fonctionnement de système de traitement sur membrane d'osmose inverse et système de traitement sur membrane d'osmose inverse

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US12221360B2 (en) 2021-09-24 2025-02-11 Bechtel Energy Technologies & Solutions, Inc. Low energy ejector desalination system

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JP2018176116A (ja) 2018-11-15
JP6565966B2 (ja) 2019-08-28

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