JP3319053B2 - Treatment method for fluoride-containing water - Google Patents

Treatment method for fluoride-containing water

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Publication number
JP3319053B2
JP3319053B2 JP19350993A JP19350993A JP3319053B2 JP 3319053 B2 JP3319053 B2 JP 3319053B2 JP 19350993 A JP19350993 A JP 19350993A JP 19350993 A JP19350993 A JP 19350993A JP 3319053 B2 JP3319053 B2 JP 3319053B2
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JP
Japan
Prior art keywords
membrane
water
fluoride
treatment
separation
Prior art date
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Expired - Fee Related
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JP19350993A
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Japanese (ja)
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JPH0747371A (en
Inventor
武 鶴見
武 佐藤
Original Assignee
栗田工業株式会社
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Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【0001】[0001]

【産業上の利用分野】本発明はフッ化物含有水の処理方
法に係り、特に、排煙脱硫排水等のフッ化物含有水を凝
集処理した後膜分離処理し、更に、フッ化物イオン吸着
材で吸着処理するフッ化物含有水の処理方法において、
分離膜の膜性能の低下防止とフッ化物イオン吸着材の再
生排液の有効利用を図る方法に関する。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating fluoride-containing water, and more particularly to a method for treating fluoride-containing water such as flue gas desulfurization effluent by coagulation treatment, followed by membrane separation treatment, and further using a fluoride ion adsorbent. In the method of treating fluoride-containing water for adsorption treatment,
The present invention relates to a method for preventing a decrease in membrane performance of a separation membrane and effectively utilizing a regenerated effluent of a fluoride ion adsorbent.

【0002】[0002]

【従来の技術】化石燃料を用いる火力発電所において
は、その排煙中のSO3 対策のために、脱硫処理が行な
われている。この脱硫処理で得られる排水は、燃料中に
含まれる重金属や、フッ素、COD成分を多く含むこと
から、そのまま放流することはできない。
2. Description of the Related Art In a thermal power plant using fossil fuel, desulfurization treatment is performed in order to take measures against SO 3 in flue gas. The wastewater obtained by this desulfurization treatment cannot be discharged as it is because it contains a large amount of heavy metals, fluorine and COD components contained in the fuel.

【0003】このため、従来、排煙脱硫装置の排水は、
2段凝集沈殿処理した後、濾過することにより、処理さ
れた後、放流されている。この2段凝集処理法では、第
1段目の凝集沈殿処理で重金属とフッ素の大部分を金属
水酸化物やフッ化カルシウムとして沈殿除去し、第2段
目の凝集沈殿処理で重金属とフッ素の残部を強アルカリ
性下でマグネシウム水酸化物と共沈させることにより処
理するものであるが、この処理法では、大きな設置面積
を必要とする沈殿槽が2槽必要であり、装置設置面積が
大きく、また、凝集剤の薬注制御が複雑であるという欠
点がある。
For this reason, conventionally, the wastewater from the flue gas desulfurization unit is
After the two-stage coagulation sedimentation treatment, the mixture is filtered and then discharged. In this two-stage flocculation treatment method, most of heavy metals and fluorine are precipitated and removed as metal hydroxide or calcium fluoride in the first flocculation and precipitation process, and heavy metals and fluorine are removed in the second flocculation and precipitation process. The remaining part is treated by coprecipitation with magnesium hydroxide under strong alkalinity. However, in this treatment method, two sedimentation tanks requiring a large installation area are required, and the equipment installation area is large. In addition, there is a disadvantage that the control of the coagulant injection is complicated.

【0004】このような欠点を解決するものとして、膜
処理によるSS分の濃縮除去が検討されている。例え
ば、フッ化物含有水にカルシウム化合物及び/又はアル
ミニウム化合物を加え、pHを6〜8に調整すると共
に、後段の膜分離工程から排出される濃縮液の少なくと
も一部を添加して撹拌し、得られた懸濁液を循環槽に導
入する反応工程、循環槽から導入された液を膜分離処理
して透過液と濃縮液とに分離する膜分離工程、膜分離工
程から排出される濃縮液の少なくとも一部を前記反応工
程に返送すると共に、残部は前記循環槽に循環する循環
工程、を備えることを特徴とするフッ化物含有水の処理
方法が本出願人より提案された(特願平1−25850
8号)。
[0004] As a solution to such a drawback, concentration and removal of SS content by membrane treatment have been studied. For example, a calcium compound and / or an aluminum compound are added to the fluoride-containing water to adjust the pH to 6 to 8, and at least a part of the concentrated liquid discharged from the subsequent membrane separation step is added and stirred to obtain A reaction step of introducing the suspension into the circulation tank, a membrane separation step of subjecting the liquid introduced from the circulation tank to membrane separation and separation into a permeate and a concentrate, and a process of the concentrate discharged from the membrane separation step. The applicant of the present invention has proposed a method for treating fluoride-containing water, comprising a circulation step of circulating at least a part to the reaction step and circulating the remainder to the circulation tank. -25850
No. 8).

【0005】このような膜処理を利用する方法では、従
来の2段凝集沈殿処理による除去効果が得られないた
め、処理水中のフッ素イオン濃度を放流規制値以下にま
で低減することは困難である。このため、膜処理の後段
に、フッ素イオンを選択的に吸着するフッ素吸着塔によ
る処理が必要となる。
In the method utilizing such a membrane treatment, the removal effect by the conventional two-stage coagulation sedimentation treatment cannot be obtained, so that it is difficult to reduce the fluorine ion concentration in the treated water to the discharge regulation value or less. . For this reason, after the membrane treatment, treatment by a fluorine adsorption tower that selectively adsorbs fluorine ions is required.

【0006】また、この膜処理を利用する方法では、懸
濁物を分離膜で濃縮分離することから、長期間の運転後
には、膜面へのシリカ系スケールの付着により、膜の処
理能力の低下が認められる。このため、膜性能の維持の
ために膜洗浄が必要となる。
In the method utilizing the membrane treatment, the suspension is concentrated and separated by a separation membrane. Therefore, after a long-term operation, the silica-based scale adheres to the membrane surface to reduce the membrane processing capacity. A decrease is observed. For this reason, membrane cleaning is required to maintain the membrane performance.

【0007】従来、一般的な膜処理装置において、膜の
洗浄操作は次のような方法で実施されている。 膜処理装置の処理水を膜濾過方向と逆方向に流す。 濃厚な酸液で浸漬洗浄する。 濃厚なアルカリ液で浸漬洗浄する。 界面活性剤で浸漬洗浄する。 酸化剤により洗浄処理する。 上記〜の洗浄方法のいずれか2種以上を組み合
せて洗浄処理する。
Conventionally, in a general film processing apparatus, a cleaning operation of a film is performed by the following method. The treated water of the membrane treatment device flows in the direction opposite to the membrane filtration direction. Immerse and wash in a concentrated acid solution. Immerse and wash with a concentrated alkaline solution. Immerse and wash with a surfactant. Washing treatment with an oxidizing agent. Washing treatment is performed by combining any two or more of the above washing methods.

【0008】洗浄操作は、上記〜の方法のうち、膜
面の付着物に応じて適当な方法が選択されて実施される
が、発電所総合排水の処理においては、重金属の酸化
物、シリカ、有機物が膜面付着物であることが多く、一
般には酸及び/又はアルカリによる洗浄処理が行なわれ
ている。
The washing operation is carried out by selecting an appropriate method from the above methods according to the deposits on the membrane surface. In the treatment of the integrated wastewater of the power plant, oxides of heavy metals, silica, Organic substances are often attached to the film surface, and generally, a cleaning treatment with an acid and / or alkali is performed.

【0009】[0009]

【発明が解決しようとする課題】しかしながら、火力発
電所総合排水処理に組み込まれた膜処理装置において、
酸及び/又はアルカリにより膜洗浄を行なった場合、実
際には、洗浄温度や浸漬時間等の制限から、洗浄処理後
も膜面に付着物が残留し、十分な洗浄効果を得ることは
できないという問題がある。
However, in a membrane treatment apparatus incorporated in a thermal power plant integrated wastewater treatment,
When the film is washed with an acid and / or an alkali, actually, due to restrictions on the washing temperature, immersion time, etc., deposits remain on the film surface even after the washing treatment, and it is not possible to obtain a sufficient washing effect. There's a problem.

【0010】本発明は、上記従来の問題点を解決し、火
力発電所総合排水等のフッ化物含有排水の処理に組み込
まれた膜処理装置の膜洗浄を効率的に行なうことができ
るフッ化物含有水の処理方法を提供することを目的とす
る。
[0010] The present invention solves the above-mentioned conventional problems, and can efficiently carry out membrane cleaning of a membrane treatment apparatus incorporated in the treatment of fluoride-containing wastewater such as thermal power plant integrated wastewater. An object of the present invention is to provide a method for treating water.

【0011】[0011]

【課題を解決するための手段】本発明のフッ化物含有水
の処理方法は、フッ化物含有水にカルシウム化合物及び
/又はアルミニウム化合物を加え、pHを6〜8に調整
し、得られた懸濁液を分離膜で膜分離して透過液と濃縮
液とに分離し、透過液をフッ化物イオン吸着材と接触さ
せてフッ化物イオンを除去するフッ化物含有水の処理方
法において、前記フッ化物イオン吸着材をアルカリと接
触させて再生し、その再生排液に酸を添加してフッ酸を
生成させた後、前記分離膜の洗浄に使用することを特徴
とする。
According to the method for treating fluoride-containing water of the present invention, a calcium compound and / or an aluminum compound is added to the fluoride-containing water, the pH is adjusted to 6 to 8, and the obtained suspension is treated. The method for treating fluoride-containing water, wherein the solution is separated into a permeate and a concentrate by membrane-separating the solution with a separation membrane, and the permeate is contacted with a fluoride ion adsorbent to remove fluoride ions. The method is characterized in that the adsorbent is regenerated by contacting with an alkali, an acid is added to the regenerated effluent to generate hydrofluoric acid, and then used for washing the separation membrane.

【0012】[0012]

【作用】フッ化物イオン吸着材の再生排液中に含有され
るフッ素由来のフッ酸は、通常の酸やアルカリによる洗
浄では除去し難い膜面付着物である、シリカを主成分と
するスケールを効率良く溶解除去する。
[Function] Fluoric acid derived from fluorine contained in the regenerated effluent of a fluoride ion adsorbent is a scale mainly composed of silica, which is a film surface deposit that is difficult to remove by washing with ordinary acid or alkali. Dissolve and remove efficiently.

【0013】因みに、フッ化物イオン吸着材を充填した
フッ素吸着塔の再生により流出する排液の組成は、図2
に示す通りであり、フッ素濃度は、最高約4g/lにま
で達する。従って、このフッ素濃度の高い流出分を分画
し、酸を添加してフッ酸を生成させることにより、効率
的な膜洗浄を行なえる。
Incidentally, the composition of the effluent discharged by regeneration of the fluorine adsorption tower filled with the fluoride ion adsorbent is shown in FIG.
And the fluorine concentration reaches up to about 4 g / l. Therefore, by separating the effluent having a high fluorine concentration and adding an acid to generate hydrofluoric acid, efficient membrane cleaning can be performed.

【0014】[0014]

【実施例】以下、図面を参照して本発明のフッ化物含有
水の処理方法を詳細に説明する。
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The method for treating fluoride-containing water according to the present invention will be described below in detail with reference to the drawings.

【0015】図1は本発明のフッ化物含有水の処理方法
の一実施例を示す系統図である。
FIG. 1 is a system diagram showing one embodiment of the method for treating fluoride-containing water of the present invention.

【0016】図示の方法においては、まず、原水である
フッ化物含有水を配管11より撹拌機1Aを備える反応
槽1に供給し、配管12よりカルシウム化合物及び/又
はアルミニウム化合物、更に必要に応じてpH調整剤を
加えてpH6〜8に調整すると共に、後段の膜分離装置
3から配管15、16を経て返送された膜分離処理の濃
縮液の少なくとも一部を添加して撹拌する。
In the illustrated method, first, fluoride-containing water, which is raw water, is supplied from a pipe 11 to a reaction tank 1 provided with a stirrer 1A, and a calcium compound and / or an aluminum compound, and if necessary, from a pipe 12. The pH is adjusted to 6 to 8 by adding a pH adjuster, and at least a part of the concentrate of the membrane separation treatment returned from the subsequent membrane separation device 3 via the pipes 15 and 16 is added and stirred.

【0017】反応槽1に添加されるカルシウム化合物と
しては、水酸化カルシウム(Ca(OH)2 )、酸化カ
ルシウム(CaO)等が挙げられる。また、アルミニウ
ム化合物としては硫酸バンド(Al2 (SO43 )、
ポリ塩化アルミニウム(PAC)等が挙げられる。これ
らは1種を単独で用いても、2種以上を併用して用いて
も良い。
Examples of the calcium compound added to the reaction tank 1 include calcium hydroxide (Ca (OH) 2 ) and calcium oxide (CaO). As the aluminum compound, a sulfuric acid band (Al 2 (SO 4 ) 3 ),
Polyaluminum chloride (PAC) and the like. These may be used alone or in combination of two or more.

【0018】反応工程においては、反応液のpHを6〜
8、好ましくは6〜7に調整するために、必要に応じて
pH調整剤を添加する。即ち、Ca(OH)2 等を添加
する場合には、Ca(OH)2 自体がpH調整剤として
作用するために、別途pH調整剤を用いる必要はない
が、硫酸バンドを添加する場合には、pH調整剤として
NaOH、Ca(OH)2 等のアルカリを添加する。本
発明においては、スケール障害の問題は解決されてお
り、従来の硫酸バンド法のようなスケール障害発生の恐
れはないため、pH調整剤としてはCa(OH)2 を用
いるのが有利である。
In the reaction step, the pH of the reaction solution is adjusted to 6 to
In order to adjust the pH to 8, preferably 6 to 7, a pH adjuster is added as required. In other words, when Ca (OH) 2 or the like is added, Ca (OH) 2 itself acts as a pH adjuster, so there is no need to use a separate pH adjuster. An alkali such as NaOH or Ca (OH) 2 is added as a pH adjuster. In the present invention, the problem of scale hindrance has been solved, and there is no risk of scale hindrance unlike the conventional sulfate band method. Therefore, it is advantageous to use Ca (OH) 2 as a pH adjuster.

【0019】カルシウム化合物及び/又はアルミニウム
化合物を添加してpHを6〜8に調整することにより、
原水中のフッ化物イオンが固体化される。即ち、カルシ
ウム化合物によりフッ化物イオンはCaF2 として析出
し、また、フッ化物イオンはアルミニウム化合物に吸着
されて析出する。この際、反応槽1には、後段の膜分離
装置3の濃縮液が返送され混合されているため、この濃
縮液中のSSが種晶として作用しスケールの生成は防止
される。
By adjusting the pH to 6 to 8 by adding a calcium compound and / or an aluminum compound,
Fluoride ions in the raw water are solidified. That is, the fluoride ion is precipitated as CaF 2 by the calcium compound, and the fluoride ion is adsorbed and precipitated by the aluminum compound. At this time, since the concentrated solution of the subsequent membrane separation device 3 is returned to and mixed with the reaction tank 1, the SS in the concentrated solution acts as a seed crystal to prevent scale formation.

【0020】反応槽1におけるカルシウム化合物及び/
又はアルミニウム化合物の添加量は、通常の場合、原水
中のフッ化物イオンに対して0.5〜3倍当量程度とす
るのが好ましい。通常、排煙脱硫排水等にはカルシウム
やアルミニウム化合物が含まれており、これらを含めて
上記の範囲とすれば良い。また、膜分離装置3から返送
する濃縮液量は、そのSS濃度によっても異なるが、原
水量に対して0.1〜4倍量程度とするのが好ましい。
The calcium compound and / or
Or, the amount of addition of the aluminum compound is usually preferably about 0.5 to 3 equivalents to the fluoride ions in the raw water. Normally, flue gas desulfurization wastewater and the like contain calcium and aluminum compounds, and the above ranges may be included including these. The amount of the concentrate returned from the membrane separation device 3 varies depending on the SS concentration, but is preferably about 0.1 to 4 times the amount of the raw water.

【0021】なお、この反応槽1における反応時間は、
通常の場合、30分以上とする。即ち、反応槽1内の反
応液から十分に析出物が生成するに要する時間、特に石
膏生成反応に要する時間は約30分程度であるため、ス
ケール障害の防止の面から、反応槽1における反応時間
は30分以上とするのが好ましい。
The reaction time in the reaction tank 1 is as follows:
Usually, it is 30 minutes or more. That is, the time required for sufficiently generating a precipitate from the reaction solution in the reaction tank 1, particularly the time required for the gypsum formation reaction, is about 30 minutes. The time is preferably 30 minutes or more.

【0022】反応槽1で得られた懸濁液は、次いで配管
13を経て循環槽2に導入する。
The suspension obtained in the reaction tank 1 is then introduced into the circulation tank 2 via a pipe 13.

【0023】循環槽2には後段の膜分離装置3から配管
15を経て排出される濃縮液のうち、配管16を経て反
応槽1に返送された濃縮液の残部が配管17を経て導入
されている。この循環槽2内の、反応槽1からの懸濁液
と膜分離装置3の濃縮液とは、ポンプ31を備える配管
14を経て、膜分離装置3に導入し、分離膜3Aにて膜
分離処理する。
Of the concentrated liquid discharged from the subsequent membrane separation device 3 through the pipe 15 into the circulation tank 2, the remaining part of the concentrated liquid returned to the reaction tank 1 through the pipe 16 is introduced through the pipe 17. I have. The suspension from the reaction tank 1 and the concentrated liquid of the membrane separation device 3 in the circulation tank 2 are introduced into the membrane separation device 3 through the pipe 14 having the pump 31 and are separated by the separation membrane 3A. To process.

【0024】なお、循環槽2の液滞留時間は1〜20時
間程度となるように設定するのが好ましい。また、循環
槽2には、経時的にSSが濃縮、蓄積されるため、この
SSは必要に応じて槽下部よりポンプ32を備える配管
18を経て系外へ排出する。
It is preferable that the residence time of the liquid in the circulation tank 2 is set to be about 1 to 20 hours. Further, since SS is concentrated and accumulated in the circulation tank 2 with time, this SS is discharged from the lower part of the tank through the pipe 18 provided with the pump 32 as needed.

【0025】膜分離装置3の分離膜3Aとしては精密濾
過(MF)膜又は限外濾過(UF)膜を用いるのが好ま
しい。MF膜を用いる場合、その孔径が大きく1μm以
上であるとフッ化物を含有する析出物が透過する場合が
ある。従って、MF膜としては孔径0.5μm以下のも
のを用いるのが好ましい。このような膜分離装置3で
は、液中の未反応のカルシウム化合物やアルミニウム化
合物は膜透過されずに濃縮水中に残留して、反応槽1に
返送されることとなり、これらは反応槽1にてフッ化物
イオンの固定化機能を発揮するため、極めて有利であ
る。
As the separation membrane 3A of the membrane separation device 3, it is preferable to use a microfiltration (MF) membrane or an ultrafiltration (UF) membrane. When the MF film is used, if the pore size is large and 1 μm or more, the precipitate containing fluoride may permeate. Therefore, it is preferable to use an MF film having a pore size of 0.5 μm or less. In such a membrane separation device 3, unreacted calcium compounds and aluminum compounds in the liquid remain in the concentrated water without being permeated through the membrane and are returned to the reaction tank 1. This is extremely advantageous because it exerts a function of immobilizing fluoride ions.

【0026】なお、逆浸透(RO)膜はCa2+、F-
SO4 2- の除去能力を有し、膜面の濃度分極によりスケ
ールが生成するため、本発明には好ましくない。
The reverse osmosis (RO) membrane is made of Ca 2+ , F ,
It has the ability to remove SO 4 2− and generates scale due to concentration polarization on the film surface, which is not preferred in the present invention.

【0027】膜分離装置3の濃縮液は、前述の如く、そ
の一部又は全部が配管15、16を経て反応槽1に返送
され、また、残部は配管17を経て循環槽2に循環され
る。
As described above, a part or all of the concentrated liquid in the membrane separation device 3 is returned to the reaction tank 1 through the pipes 15 and 16, and the remainder is circulated to the circulation tank 2 through the pipe 17. .

【0028】一方、膜分離装置3の透過液は、配管19
より撹拌機4Aを備えるpH調整槽4に送給し、必要に
応じてNaOH、HCl等のpH調整剤を配管20より
添加してpH2〜9程度にpH調整した後、ポンプ33
を備える配管21よりCOD吸着塔5へ導入して吸着処
理して、膜分離装置3の透過液になお残留しているCO
D成分を吸着除去する。
On the other hand, the permeate of the membrane separation device 3 is
The mixture is fed to a pH adjusting tank 4 having a stirrer 4A, and if necessary, a pH adjusting agent such as NaOH or HCl is added from a pipe 20 to adjust the pH to about 2 to 9, and then a pump 33
Is introduced into the COD adsorption tower 5 through a pipe 21 equipped with
The D component is adsorbed and removed.

【0029】このCOD吸着塔5の流出水は、配管22
より撹拌機6Aを備えるpH調整槽6に送給し、必要に
応じてNaOH、HCl等のpH調整剤を配管23より
添加してpH3〜7程度にpH調整した後、ポンプ34
を備える配管24よりフッ素吸着塔7へ導入して吸着処
理し、なお残留しているフッ化物イオンを吸着除去す
る。フッ素吸着塔7の流出水は処理水として配管25よ
り系外へ排出される。
The effluent of the COD adsorption tower 5 is supplied to a pipe 22
The mixture is fed to a pH adjusting tank 6 equipped with a stirrer 6A, and if necessary, a pH adjusting agent such as NaOH or HCl is added from a pipe 23 to adjust the pH to about 3 to 7, and then a pump 34
Is introduced into the fluorine adsorption tower 7 through the pipe 24 provided with the above, and is subjected to the adsorption treatment, and the fluoride ions still remaining are adsorbed and removed. The effluent from the fluorine adsorption tower 7 is discharged out of the system through a pipe 25 as treated water.

【0030】なお、フッ化物イオン吸着材としては、ト
リチウム,ジルコニウム,チタニウム又はハフニウム型
カチオン交換樹脂、強,弱酸性カチオン交換樹脂、ハロ
アルキルシラン系吸着樹脂、弱塩基性アニオン交換樹
脂、希土類金属水和酸化物型キレート樹脂、Al塩型キ
レート樹脂等の吸着樹脂、その他活性アルミナ、マグネ
シア系吸着剤等が挙げられる。また、COD吸着材とし
ては、ゲル型又はMR型弱,中,強塩基性アニオン交換
樹脂等のCOD吸着樹脂、その他活性炭等が挙げられ
る。
The fluoride ion adsorbents include tritium, zirconium, titanium or hafnium type cation exchange resins, strong and weakly acidic cation exchange resins, haloalkylsilane-based adsorption resins, weakly basic anion exchange resins, and rare earth metal hydrates. Adsorption resins such as oxide-type chelate resins and Al-salt-type chelate resins, as well as other activated aluminas and magnesia-type adsorbents are exemplified. Examples of the COD adsorbent include a COD adsorbing resin such as a gel type or MR type weak, medium, and strong basic anion exchange resin, and other activated carbon.

【0031】本発明においては、このような処理におい
て、フッ素吸着塔内のフッ化物イオン吸着材をNaOH
等のアルカリと接着させて再生処理する際に得られる再
生排液のうち、フッ素濃度の高い流分を配管26より貯
槽8に回収する。そして、膜分離装置3の分離膜3Aの
性能が低下したときには、処理系の運転を停止して、こ
の貯槽8内の再生排液及び貯槽9内の酸溶液を、それぞ
れポンプ35を備える配管26及びポンプ36を備える
配管27より混合して配管28を経て膜分離装置3内に
導入して所定時間浸漬洗浄を行なう。その後、水洗した
後、貯槽10内のアルカリ溶液をポンプ37を備える配
管29及び28を経て膜分離装置内に導入して所定時間
浸漬洗浄した後、水洗する。
In the present invention, in such treatment, the fluoride ion adsorbent in the fluorine adsorption tower is replaced with NaOH.
Among the regenerated effluent obtained when the regenerating process is performed by bonding with an alkali such as, for example, a stream having a high fluorine concentration is collected in the storage tank 8 from the pipe 26. When the performance of the separation membrane 3A of the membrane separation device 3 decreases, the operation of the processing system is stopped, and the regenerated wastewater in the storage tank 8 and the acid solution in the storage tank 9 are supplied to a pipe 26 having a pump 35, respectively. Then, the mixture is mixed from a pipe 27 provided with a pump 36 and introduced into the membrane separation device 3 through a pipe 28, and immersion cleaning is performed for a predetermined time. Thereafter, after washing with water, the alkaline solution in the storage tank 10 is introduced into the membrane separation device through the pipes 29 and 28 provided with the pump 37, immersed and washed for a predetermined time, and then washed with water.

【0032】このような膜洗浄処理により、膜面の付着
物は効率的に洗浄除去され、膜性能が回復する。この膜
洗浄により得られる洗浄排液は、配管30を経て反応槽
に導入し、原水と共に処理され、含有されるシリカ、フ
ッ素が除去される。
By such a film cleaning treatment, the deposits on the film surface are efficiently cleaned and removed, and the film performance is restored. The cleaning effluent obtained by this membrane cleaning is introduced into a reaction tank via a pipe 30, and is treated together with raw water to remove silica and fluorine contained therein.

【0033】このような膜洗浄に用いる再生排液は、フ
ッ素を500mg/l以上の高濃度で含むものが好まし
い。また、このような再生排液に添加する酸の割合は、
再生排液のpHによって異なり、通常の場合、再生排液
をpH3.5以下程度の酸性とするような割合で添加さ
れる。
The regenerated effluent used for such membrane cleaning preferably contains fluorine at a high concentration of 500 mg / l or more. Also, the proportion of acid added to such reclaimed effluent is
It depends on the pH of the regenerated effluent, and is usually added at such a rate that the regenerated effluent is acidified to a pH of about 3.5 or less.

【0034】本発明において、原水のフッ化物含有水と
しては特に制限はないが、例えば排煙脱硫及び/又は脱
硝排水、アルミニウム電解精錬工程排水、リン酸肥料の
製造工程排水、シリコン等の電気部品の洗浄工程、ウラ
ン精錬工程、表面処理洗浄工程排水等が挙げられ、本発
明は特に火力発電所向け総合排水処理に好適である。
In the present invention, the fluoride-containing water of the raw water is not particularly limited. For example, flue gas desulfurization and / or denitrification wastewater, aluminum electrolytic refining process wastewater, phosphate fertilizer production process wastewater, and electrical components such as silicon The present invention is particularly suitable for comprehensive wastewater treatment for thermal power plants.

【0035】なお、図1に示す例は本発明の一実施例で
あって、本発明は何ら図示の方法に限定されるものでは
ない。本実施例方法においては、膜分離装置の透過液を
CODに吸着処理しているが、透過液が十分に高水質の
場合であれば、COD吸着処理は行なわなくても良い。
また、吸着処理において、吸着塔は上向流で処理しても
下向流で処理しても良いことは言うまでもないが、一般
に、フッ化物イオン吸着及びCOD吸着は下向流にて処
理を行なう。更に、膜分離装置の濃縮水は必ずしも反応
槽及び循環槽に返送する必要はないが、この濃縮液の返
送により、前述の如く、スケールの生成防止が図れ、有
利である。
The example shown in FIG. 1 is an embodiment of the present invention, and the present invention is not limited to the illustrated method. In the method of the present embodiment, the permeate of the membrane separation device is adsorbed on COD, but if the permeate has sufficiently high water quality, the COD adsorption process may not be performed.
In addition, in the adsorption treatment, it goes without saying that the adsorption tower may be treated in an upward flow or in a downward flow, but generally, fluoride ion adsorption and COD adsorption are performed in a downward flow. . Furthermore, although the concentrated water of the membrane separation device does not necessarily need to be returned to the reaction tank and the circulation tank, the return of the concentrated liquid is advantageous in that scale formation can be prevented as described above.

【0036】以下に具体的な実施例を挙げる。Specific examples will be described below.

【0037】実施例1 実際の火力発電所排煙脱硫廃水を用いて、図1に示す方
法で処理を行なった。なお、膜分離装置としては、孔径
0.5μmで面積0.2m2 の分離膜を設けたものを用
いた。
Example 1 The treatment was performed by the method shown in FIG. 1 using the actual flue gas desulfurization wastewater of a thermal power plant. As the membrane separation apparatus, an apparatus provided with a separation membrane having a pore diameter of 0.5 μm and an area of 0.2 m 2 was used.

【0038】まず、新膜を用いて、約1ケ月の通水処理
を行なった結果、膜の性能を示すフラックス(透過流
束)は、図3の□で示す通り、当初の12m/dayか
ら8m/dayに低下した。
First, as a result of performing a water-passing treatment for about one month using a new membrane, the flux (permeation flux) showing the performance of the membrane is reduced from the initial 12 m / day as shown by the square in FIG. It decreased to 8 m / day.

【0039】そこで、4重量%HCl水溶液5リットル
を膜分離装置内に導入し、5時間静置した後水洗し、次
いで、2重量%NaOH水溶液5リットルを膜分離装置
内に導入し、4時間静置した後、水洗した(洗浄処理
I)。この洗浄処理I後、第2回目の通水を行なったと
ころ、図3の+で示す如く、フラックスは当初9.2m
/dayから、1ケ月後5.9m/dayとなり、新膜
に比べて25%の性能低下であった。
Then, 5 liters of a 4% by weight aqueous solution of HCl was introduced into the membrane separator, left standing for 5 hours, washed with water, and then 5 liters of a 2% by weight aqueous solution of NaOH was introduced into the membrane separator, followed by 4 hours. After standing, it was washed with water (washing treatment I). After this cleaning treatment I, the second water passage was performed. As shown by + in FIG. 3, the flux was initially 9.2 m.
/ Day, it was 5.9 m / day one month later, and the performance was 25% lower than that of the new film.

【0040】この通水後、4重量%HCl水溶液5リッ
トルを膜分離装置内に導入し、5時間静置した後水洗
し、次いで、50℃に加温した2重量%NaOH水溶液
5リットルを膜分離装置内に導入し、4時間静置した
後、水洗した(洗浄処理II)。この洗浄処理II後、第3
回目の通水を行なったところ、図3の◇で示す如く、フ
ラックスは当初8.0m/dayから、1ケ月後5.2
m/dayとなり、性能の低下を防止することはできな
かった。
After passing the water, 5 liters of a 4% by weight aqueous solution of HCl was introduced into the membrane separator, left standing for 5 hours, washed with water, and then 5 liters of a 2% by weight aqueous solution of NaOH heated to 50 ° C. After being introduced into the separation device and allowed to stand for 4 hours, it was washed with water (washing treatment II). After this cleaning treatment II, the third
When the water was passed for the first time, the flux was initially 8.0 m / day, 5.2 months after one month, as shown by ◇ in FIG.
m / day, and a decrease in performance could not be prevented.

【0041】このとき、膜面付着物の一部を採取して組
成分析を行なった結果、付着スケールの主成分はシリカ
及びアルミナであることが判明した。
At this time, a part of the deposit on the film surface was sampled and analyzed for composition. As a result, it was found that the main components of the deposit scale were silica and alumina.

【0042】そこで、別途調製した、下記性状のフッ素
吸着塔の模擬再生排液3リットルと8重量%HCl水溶
液0.5リットルとを混合した液(pH2.8)を膜分
離装置内に導入し、5時間静置した後水洗し、次いで、
2重量%NaOH水溶液5リットルを膜分離装置内に導
入し、4時間静置した後水洗した(洗浄処理III )。
Therefore, a separately prepared liquid (pH 2.8) obtained by mixing 3 liters of the simulated regenerated effluent of the fluorine adsorption tower having the following properties and 0.5 liter of an 8% by weight HCl aqueous solution was introduced into the membrane separation apparatus. After standing still for 5 hours, wash with water,
Five liters of a 2% by weight NaOH aqueous solution was introduced into the membrane separation device, allowed to stand for 4 hours, and then washed with water (washing treatment III).

【0043】模擬再生排液(性状) フッ素濃度 :3300mg/l SO4 2- 濃度 : 300mg/l PO4 3- −P濃度: 100mg/l pH :13.1 この洗浄処理III 後、第4回目の通水を行なったとこ
ろ、図3の△で示す如く、フラックスは当初9.2m/
dayから、1ケ月後8m/dayとなり、新膜と殆ど
同等の性能が得られた。
Simulated regenerated effluent (property) Fluorine concentration: 3300 mg / l SO 4 2- concentration: 300 mg / l PO 4 3- -P concentration: 100 mg / l pH: 13.1 The fourth time after this washing treatment III As a result, the flux was initially 9.2 m /
From day, it became 8 m / day one month later, and almost the same performance as the new film was obtained.

【0044】[0044]

【発明の効果】以上詳述した通り、本発明のフッ化物含
有水の処理方法によれば、フッ化物イオン吸着材の再生
排液を利用して、フッ化物含有の処理に組み込まれた膜
処理装置の分離膜に付着した、従来の膜洗浄処理では除
去困難なシリカを主成分とするスケールを効率的に洗浄
除去することができる。このため、本発明によれば、膜
性能の低下防止及び再生排液の有効利用が図れ、工業的
に極めて有利である。
As described above in detail, according to the method for treating fluoride-containing water of the present invention, the membrane treatment incorporated in the treatment containing fluoride by utilizing the regenerated effluent of the fluoride ion adsorbent. It is possible to efficiently remove and remove the scale mainly composed of silica, which is attached to the separation membrane of the apparatus and is difficult to remove by the conventional membrane cleaning treatment. For this reason, according to the present invention, it is possible to prevent the deterioration of the membrane performance and to effectively use the regenerated effluent, which is industrially extremely advantageous.

【図面の簡単な説明】[Brief description of the drawings]

【図1】本発明のフッ化物含有水の処理方法の一実施例
を示す系統図である。
FIG. 1 is a system diagram showing one embodiment of a method for treating fluoride-containing water of the present invention.

【図2】フッ素吸着塔再生排液の流出水の性状を示すグ
ラフである。
FIG. 2 is a graph showing properties of an effluent of a regenerated effluent of a fluorine adsorption tower.

【図3】実施例1における各通水試験時のフラックスの
経時変化を示すグラフである。
FIG. 3 is a graph showing a temporal change of a flux at the time of each water flow test in Example 1.

【符号の説明】[Explanation of symbols]

1 反応槽 2 循環槽 3 膜分離装置 4,6 pH調整槽 5 COD吸着塔 7 フッ素吸着塔 8,9,10 貯槽 DESCRIPTION OF SYMBOLS 1 Reaction tank 2 Circulation tank 3 Membrane separation device 4,6 pH adjustment tank 5 COD adsorption tower 7 Fluorine adsorption tower 8,9,10 Storage tank

───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 FI C02F 9/00 503 C02F 9/00 503G (56)参考文献 特開 平5−253576(JP,A) 特開 平4−371292(JP,A) 特開 平3−118897(JP,A) 特開 昭61−192385(JP,A) 特開 昭57−84704(JP,A) 特開 昭62−298490(JP,A) (58)調査した分野(Int.Cl.7,DB名) C02F 1/58 C02F 1/28 C02F 1/44 B01D 65/00 ──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. 7 Identification symbol FI C02F 9/00 503 C02F 9/00 503G (56) References JP-A-5-253576 (JP, A) JP-A-4-371292 (JP, A) JP-A-3-118897 (JP, A) JP-A-61-192385 (JP, A) JP-A-57-84704 (JP, A) JP-A-62-298490 (JP, A) ( 58) Field surveyed (Int.Cl. 7 , DB name) C02F 1/58 C02F 1/28 C02F 1/44 B01D 65/00

Claims (1)

(57)【特許請求の範囲】(57) [Claims] 【請求項1】 フッ化物含有水にカルシウム化合物及び
/又はアルミニウム化合物を加え、pHを6〜8に調整
し、得られた懸濁液を分離膜で膜分離して透過液と濃縮
液とに分離し、透過液をフッ化物イオン吸着材と接触さ
せてフッ化物イオンを除去するフッ化物含有水の処理方
法において、前記フッ化物イオン吸着材をアルカリと接
触させて再生し、その再生排液に酸を添加してフッ酸を
生成させた後、前記分離膜の洗浄に使用することを特徴
とするフッ化物含有水の処理方法。
1. A calcium compound and / or an aluminum compound are added to fluoride-containing water to adjust the pH to 6 to 8, and the obtained suspension is subjected to membrane separation with a separation membrane to form a permeate and a concentrate. In the method for treating fluoride-containing water for separating and contacting the permeate with a fluoride ion adsorbent to remove fluoride ions, the fluoride ion adsorbent is regenerated by contacting it with an alkali, A method for treating fluoride-containing water, comprising using an acid to generate hydrofluoric acid and then washing the separation membrane.
JP19350993A 1993-08-04 1993-08-04 Treatment method for fluoride-containing water Expired - Fee Related JP3319053B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP19350993A JP3319053B2 (en) 1993-08-04 1993-08-04 Treatment method for fluoride-containing water

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP19350993A JP3319053B2 (en) 1993-08-04 1993-08-04 Treatment method for fluoride-containing water

Publications (2)

Publication Number Publication Date
JPH0747371A JPH0747371A (en) 1995-02-21
JP3319053B2 true JP3319053B2 (en) 2002-08-26

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Country Status (1)

Country Link
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JP2003340210A (en) * 2002-05-28 2003-12-02 Japan Organo Co Ltd Cleaning method for filter apparatus
JP4591170B2 (en) * 2004-11-15 2010-12-01 パナソニック株式会社 Fluorine-containing water treatment equipment
JP4633079B2 (en) * 2007-03-09 2011-02-23 三洋電機株式会社 Method and apparatus for treating fluorine-containing water
JP4902450B2 (en) * 2007-07-13 2012-03-21 Dowaメタルマイン株式会社 Arsenic treatment method
JP2009207953A (en) * 2008-02-29 2009-09-17 Sanyo Electric Co Ltd Wastewater treatment apparatus and method
JP5393409B2 (en) * 2009-11-12 2014-01-22 三菱重工業株式会社 Waste water treatment apparatus and waste water treatment method
JP5319730B2 (en) * 2011-05-10 2013-10-16 株式会社東芝 Fluorine recovery device and fluorine recovery method
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JPH0753276B2 (en) * 1989-10-03 1995-06-07 栗田工業株式会社 Fluoride-containing water treatment method
JP2503806B2 (en) * 1991-06-19 1996-06-05 電源開発株式会社 Fluoride-containing water treatment method
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