JP2001191086A - Water treating apparatus - Google Patents

Water treating apparatus

Info

Publication number
JP2001191086A
JP2001191086A JP2000001392A JP2000001392A JP2001191086A JP 2001191086 A JP2001191086 A JP 2001191086A JP 2000001392 A JP2000001392 A JP 2000001392A JP 2000001392 A JP2000001392 A JP 2000001392A JP 2001191086 A JP2001191086 A JP 2001191086A
Authority
JP
Japan
Prior art keywords
water
membrane
ozone
treatment
acid
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.)
Granted
Application number
JP2000001392A
Other languages
Japanese (ja)
Inventor
Shigeki Sawada
繁樹 澤田
Original Assignee
Kurita Water Ind Ltd
栗田工業株式会社
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 Ind Ltd, 栗田工業株式会社 filed Critical Kurita Water Ind Ltd
Priority to JP2000001392A priority Critical patent/JP2001191086A/en
Publication of JP2001191086A publication Critical patent/JP2001191086A/en
Granted legal-status Critical Current

Links

Abstract

PROBLEM TO BE SOLVED: To provide a water treating apparatus which can be operated or worked stably, is improved in performance for removing a TOC component and can be used as a water purifying apparatus which produces drinkable water and various kinds of service water or a high-degree treating apparatus which further treats biologically treated water to a higher degree. SOLUTION: This water treating apparatus comprises an ozonating means which ozonates raw water, a membrane filtering means which separates and removes suspended materials and insoluble substances in water by passing the water which is subjected to ozonating treatment therethrough and a deionizing means which deionizes a membrane filtration water. Therein, an acid adding means is disposed on a front stage of the ozonating means or/and on the ozonating means.

Description

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

【0001】[0001]

【発明の属する技術分野】本発明は、安定に運転(稼
働)できると共にTOC成分の除去性能を向上すること
ができ、飲料水や各種用水を製造する浄水装置として、
或いは生物処理水をさらに高度処理する高度処理装置と
して使用することができる水処理装置に関する。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water purification device which can stably operate (operate) and improve the TOC component removal performance, and can produce drinking water and various kinds of water.
Alternatively, the present invention relates to a water treatment apparatus that can be used as an advanced treatment apparatus for further treating biologically treated water.

【0002】[0002]

【従来の技術】逆浸透膜(RO)を用いた脱塩装置を長
期間に亘って安定な状態で運転維持するために、原水中
の濁質を除去する装置として、凝集処理と沈殿、或いは
浮上、砂ろ過等の設備を組み合わせる方式が一般的に採
用されてきた。しかし、この従来の方式では、硫酸アル
ミニウム、ポリ塩化アルミニウム等のアルミニウム系凝
集剤や、塩化第二鉄、ポリ硫酸鉄等の鉄系凝集剤等を用
いた凝集操作が必要であり、原水の水質変動に対応した
凝集剤の添加量の調整やpH条件の調整など煩雑な操作
が必要であった。さらに、原水中の有機物濃度が高まる
と、凝集剤を多量に添加する必要があるが、このように
凝集剤が過剰に添加されると、凝集しきれない微量の溶
解状態の凝集剤が処理水中に残存し、この凝集剤がRO
で濃縮される過程で再凝集し、RO膜の表面に固着し、
薬品洗浄頻度を高める(=薬品洗浄間隔を短くする)と
いう問題もあった。
2. Description of the Related Art In order to maintain the operation of a desalination apparatus using a reverse osmosis membrane (RO) in a stable state for a long period of time, a coagulation treatment and precipitation, or A system that combines equipment such as floating and sand filtration has been generally adopted. However, this conventional method requires an aggregating operation using an aluminum-based flocculant such as aluminum sulfate or polyaluminum chloride, or an iron-based flocculant such as ferric chloride or polyiron sulfate. Complicated operations such as adjustment of the amount of coagulant added and adjustment of pH conditions corresponding to the fluctuation were required. Furthermore, when the organic matter concentration in the raw water increases, it is necessary to add a large amount of a coagulant.However, when the coagulant is added in such an excessive amount, a small amount of a coagulant in a dissolved state that cannot be coagulated is generated. And the flocculant remains in the RO
Re-agglomerates in the process of being concentrated in and adheres to the surface of the RO membrane,
There was also a problem of increasing the frequency of chemical cleaning (= shortening the chemical cleaning interval).

【0003】近年、限外ろ過(UF)膜や精密ろ過(M
F)膜の技術進歩により、前記従来の砂ろ過に代えてこ
れらUF膜やMF膜を用いた膜ろ過を、ROの前処理と
して組み合わせた方式が用いられるようになった。この
方式では、用いた膜孔径以上の濁質成分を確実に除去す
ることができるために凝集処理を必ずしも必要とせず、
そのため凝集剤による逆浸透膜の汚染を抑止し、薬品洗
浄頻度を低くし(=薬品洗浄間隔を長くし)、ROの運
転効率を向上させることができる。
In recent years, ultrafiltration (UF) membranes and microfiltration (M
F) With the technical advance of the membrane, a system in which the membrane filtration using the UF membrane and the MF membrane is combined as the RO pretreatment instead of the conventional sand filtration has come to be used. In this method, agglomerated treatment is not necessarily required because a turbid component larger than the used pore diameter of the membrane can be reliably removed.
Therefore, the contamination of the reverse osmosis membrane by the coagulant can be suppressed, the frequency of chemical cleaning can be reduced (= the chemical cleaning interval is lengthened), and the operating efficiency of RO can be improved.

【0004】[0004]

【発明が解決しようとする課題】しかしながら、前記U
F膜やMF膜を用いた膜ろ過をROの前処理として組み
合わせた方式では、除去対象とする粘土鉱物や微生物等
の他に、高分子状のフミン酸やフルボ酸に代表される溶
存有機成分もUF膜やMF膜に吸着・沈着されるため、
特にこれらの濃度が高い原水の場合には頻繁な洗浄操作
が必要であった。しかも、高分子状のフミン酸やフルボ
酸による膜汚染に関しては、UF膜やMF膜の洗浄手段
として一般的に知られている水逆洗では除去できないた
め、薬品による洗浄を行う必要があった。また、薬品洗
浄サイクルを延ばすため膜ろ過流束を低く設定すると、
多大な膜面積が必要となり装置の建設費用を増大させる
という新たな問題が生ずるものであった。さらに、ごく
一部の溶存有機成分は上述のようにUF膜やMF膜にて
除去されるものの、基本的には後段のROに依存するも
のであるから、その負担が大きく、特に高度な除去率が
要求される超純水製造においてはROを多段に配置する
などの複雑なシステムを必要とするものであった。そこ
で、本出願人は特願平10−228862号にて膜ろ過
装置の前段にオゾン酸化処理装置を配置し、オゾンによ
る原水中の溶存有機成分を分解させる方式を提案し、U
F膜やMF膜の膜汚染を抑制し、充分な溶存有機成分の
除去性能を有することを見出したが、さらに鋭意検討の
末、より一層多大な効果を有する本発明に至った。
However, the above U
In the method combining membrane filtration using F membrane and MF membrane as pretreatment of RO, in addition to clay minerals and microorganisms to be removed, dissolved organic components typified by polymeric humic acid and fulvic acid Is also adsorbed and deposited on UF and MF membranes,
Particularly in the case of raw water having a high concentration thereof, frequent washing operations were required. In addition, membrane contamination by polymeric humic acid or fulvic acid cannot be removed by water backwashing, which is generally known as a cleaning means for UF and MF membranes, so it was necessary to perform chemical cleaning. . Also, if the membrane filtration flux is set low to extend the chemical washing cycle,
A new problem arises in that a large membrane area is required and the construction cost of the apparatus is increased. Furthermore, although a very small part of the dissolved organic components is removed by the UF film or the MF film as described above, since it depends on the RO in the latter stage, the burden is large, and particularly high removal is required. In ultrapure water production requiring a high rate, a complicated system such as arranging ROs in multiple stages has been required. In view of this, the present applicant has proposed in Japanese Patent Application No. 10-228862 a method in which an ozone oxidation treatment device is arranged in front of a membrane filtration device to decompose dissolved organic components in raw water by ozone.
It has been found that the film contamination of the F film and the MF film is suppressed, and that the film has a sufficient ability to remove dissolved organic components. However, after further intensive studies, the present invention has an even greater effect.

【0005】[0005]

【課題を解決するための手段】本発明の水処理装置は、
原水をオゾン酸化するオゾン酸化処理手段と、オゾン酸
化処理された水を通水して、水中の懸濁物質、不溶性物
質を分離除去する膜ろ過手段と、膜ろ過水を脱イオン処
理する脱イオン処理手段とを備えた水処理装置におい
て、前記オゾン酸化処理手段の前段又は/及びオゾン酸
化処理手段に酸添加手段を設けたことを特徴とする。
尚、上記脱イオン処理手段に通水する膜ろ過水に、還元
剤を添加する還元剤供給手段を設けることが望ましい。
The water treatment apparatus of the present invention comprises:
Ozone oxidation treatment means for oxidizing raw water with ozone, membrane filtration means for separating and removing suspended and insoluble substances in water by passing ozone oxidized water, and deionization for deionizing membrane filtered water A water treatment apparatus provided with a treatment means, wherein an acid addition means is provided in a preceding stage of the ozone oxidation treatment means and / or in the ozone oxidation treatment means.
In addition, it is desirable to provide a reducing agent supply means for adding a reducing agent to the membrane filtered water passing through the deionizing means.

【0006】[0006]

【発明の実施の形態】まず、本発明の水処理装置を構成
する各装置について説明する。本発明に適用するオゾン
酸化処理手段としては、オゾン含有ガスと原水とを接触
させることができるものであれば任意形式の気液接触装
置を使用することができる。例えば槽内に一時水が貯留
される槽の頂部に設けた散水装置から原水を散水し、槽
底部付近に設けられる散気装置からオゾン含有ガスを散
気し、ガスと水が向流接触する向流式気液接触装置を使
用することができる。また、接触槽内に充填層を設けた
装置でもよく、水貯留槽の下部に単に水とオゾンとを供
給するものでも良い。オゾン溶解量は、原水中の有機物
を酸化するのに必要な反応当量以上、好ましくは2〜2
0倍量とする。さらに、オゾンを溶解した水は、膜ろ過
装置に供給するまでに酸化反応が行われるように滞留時
間を考慮することが望ましく、TOC濃度、オゾン濃度
にもよるが、通常、1〜60分程度とする。そして、オ
ゾンが残存している状態で膜ろ過装置に通水することが
好ましい。これは膜面に沈着した汚損物質を分解除去す
るためである。
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, each device constituting the water treatment apparatus of the present invention will be described. As the ozone oxidation treatment means applied to the present invention, any type of gas-liquid contact device can be used as long as it can contact the ozone-containing gas with the raw water. For example, raw water is sprinkled from a sprinkler provided at the top of the tank in which water is temporarily stored in the tank, and an ozone-containing gas is sparged from an air diffuser provided near the bottom of the tank, and the gas and water come into countercurrent contact. A countercurrent gas-liquid contactor can be used. Further, a device in which a packed bed is provided in the contact tank may be used, or water and ozone may be simply supplied to the lower part of the water storage tank. The amount of dissolved ozone is at least the reaction equivalent required to oxidize the organic matter in the raw water, preferably from 2 to 2.
The amount is set to 0 times. Further, it is desirable to consider the residence time of the water in which ozone is dissolved so that the oxidation reaction is performed before the water is supplied to the membrane filtration device, and although it depends on the TOC concentration and the ozone concentration, it is usually about 1 to 60 minutes. And Then, it is preferable to pass water through the membrane filtration device while ozone remains. This is to decompose and remove fouling substances deposited on the membrane surface.

【0007】また、本発明に適用される膜ろ過手段とし
ては、限外ろ過装置(UF)または精密ろ過装置(M
F)が一般的に用いられるが、通常知られている任意形
式の装置を用いることができ、平膜、中空糸膜、管状膜
のいずれでもよく、また、膜に原水を加圧供給して透過
水を得る加圧型でも膜装置を水槽内に浸漬し、透過水側
を減圧して透過水を得る減圧型でも良い。尚、膜はセラ
ミック、4フッ化ポリエチレン、フッ化ポリビニリデン
等のオゾン耐性を有する素材から構成する。
The membrane filtration means applied to the present invention may be an ultrafiltration device (UF) or a microfiltration device (M
Although F) is generally used, any type of device that is generally known can be used, and any of a flat membrane, a hollow fiber membrane, and a tubular membrane may be used. A pressurized type for obtaining permeated water or a reduced pressure type for immersing the membrane device in a water tank and depressurizing the permeated water side to obtain permeated water may be used. The membrane is made of an ozone-resistant material such as ceramic, tetrafluoroethylene, or polyvinylidene fluoride.

【0008】さらに、本発明に適用される脱イオン処理
手段としては、特に限定されるものではないが、薬剤に
よる再生処理が不要な逆浸透膜(RO)装置、電気再生
式脱イオン装置、電気透析装置を使用することが好まし
い。特に好ましくは、有機物の除去能力を有するRO装
置を使用する。このRO装置は、塩類、イオン性物質を
逆浸透膜作用で分離、除去するものであって、通常知ら
れている任意形式の膜、装置を用いることができる。水
の回収率、運転圧等についても何等限定するものではな
い。尚、原水の水質や目的とする水質によって、上記脱
イオン処理手段を複数段に設けても良いし、二種以上を
併用しても良い。例えばRO装置を多段に設けても良い
し、RO脱塩装置の後段に電気再生式脱イオン装置を設
けるようにしても良い。
Further, the deionizing means applied to the present invention is not particularly limited, but a reverse osmosis membrane (RO) device which does not require a regenerating treatment with a chemical, an electric regenerating type deionizing device, Preferably, a dialysis device is used. Particularly preferably, an RO device having an ability to remove organic substances is used. This RO apparatus separates and removes salts and ionic substances by the action of a reverse osmosis membrane, and any type of membrane or apparatus generally known can be used. The water recovery rate, operating pressure and the like are not limited at all. Depending on the quality of the raw water and the desired quality of the water, the deionization means may be provided in a plurality of stages, or two or more types may be used in combination. For example, an RO device may be provided in multiple stages, or an electric regeneration type deionization device may be provided downstream of the RO desalination device.

【0009】また、本発明に適用される酸添加手段とし
ては、例えば酸貯留タンクから薬注配管、薬注ポンプを
介して前記オゾン酸化処理手段の前に設けられる貯水槽
に添加するようにしても良いし、オゾン酸化処理手段内
へ添加するようにしても良いし、両方に添加しても良
い。この酸としては、特に限定されるものではないが、
鉱酸を使用することが好ましく、特に硫酸、塩酸を好適
に使用することができる。さらに、酸の添加量は、原水
中のフミン質等の有機成分の表面荷電密度や疎水性等の
化学的性質を改質することによって、オゾンがアタック
する部位を増やすことにより、見掛け上のオゾン酸化を
促進するような量とし、具体的にはpH6以下、好まし
くはpH3〜6程度が好ましい。pHが3より低いと、
腐食などの点であまり好ましくない。
Further, the acid addition means applied to the present invention is, for example, such that the acid is added from an acid storage tank to a water storage tank provided in front of the ozone oxidation treatment means via a chemical injection pipe and a chemical injection pump. Or may be added into the ozone oxidation treatment means, or may be added to both. The acid is not particularly limited,
It is preferable to use a mineral acid, and particularly, sulfuric acid and hydrochloric acid can be suitably used. Furthermore, the amount of acid added can be increased by increasing the number of sites where ozone attacks by modifying the surface charge density and chemical properties such as hydrophobicity of organic components such as humic substances in the raw water. The amount is such as to promote oxidation, and specifically, pH 6 or less, preferably about pH 3 to 6. If the pH is lower than 3,
It is not very desirable in terms of corrosion and the like.

【0010】本発明者の研究によれば、脱イオン処理手
段の前処理として用いられる膜ろ過手段の前段でオゾン
酸化処理を実施することにより、原水中のTOC成分で
ある高分子状のフミン酸やフルボ酸が酸化分解され、高
分子状の成分を減少させることができる。しかもそのオ
ゾン酸化処理では酸添加手段から添加された酸によりオ
ゾン酸化が促進する。こうしてオゾン酸化された水を膜
ろ過手段に通水させるので、膜ろ過手段におけるUF膜
やMF膜には逆洗で容易に除去可能な有機成分が捕捉さ
れる。また、オゾン共存下で膜ろ過手段に通水すること
により、膜面に沈着した汚染物を酸化分解させることが
できる。さらに、その後段の脱イオン処理手段にRO装
置を使用した場合、RO膜装置にてTOC成分の透過は
阻止される。また、電気再生式脱イオン装置や電気透析
装置などの荷電性の脱イオン処理手段においても、オゾ
ン酸化処理により有機成分が分解して低分子化され荷電
状態のTOC成分が増加するので、TOC成分は除去さ
れる。しかし、一部のTOC成分は前段の膜ろ過手段に
て除去されているので、脱イオン処理手段でのTOC成
分の負荷は軽減される。したがって、本発明の水処理装
置は、安定に運転(稼働)でき、TOC成分の除去性能
が高いものとなる。また、ポリアミド系のRO装置で
は、RO膜においても荷電性を帯びているため、TOC
成分の透過阻止性(除去性)が高まるという効果ももた
らされる。このように本発明の水処理装置は、酸添加手
段により見掛けのオゾン酸化を促進した結果、膜の有機
物によるファウリングを抑制し、膜ろ過流束を高く設定
でき、TOC成分の除去率も増大させることができる。
According to the study of the present inventor, high-molecular humic acid which is a TOC component in raw water is obtained by performing ozone oxidation treatment before a membrane filtration means used as a pretreatment of a deionization treatment means. And fulvic acid are oxidatively decomposed to reduce high molecular components. Moreover, in the ozone oxidation treatment, the ozone oxidation is promoted by the acid added from the acid addition means. Since the ozone-oxidized water is passed through the membrane filtration unit, the UF membrane and the MF membrane in the membrane filtration unit trap organic components that can be easily removed by backwashing. In addition, by passing water through the membrane filtration means in the presence of ozone, contaminants deposited on the membrane surface can be oxidized and decomposed. Further, when an RO device is used in the subsequent deionization means, the permeation of the TOC component is prevented by the RO membrane device. Also, in charged deionization processing means such as an electric regeneration type deionization device and an electrodialysis device, the organic component is decomposed by the ozone oxidation treatment to reduce the molecular weight and the charged TOC component increases. Is removed. However, since a part of the TOC component has been removed by the preceding membrane filtration means, the load of the TOC component on the deionization treatment means is reduced. Therefore, the water treatment apparatus of the present invention can be operated (operated) stably and has high TOC component removal performance. In the case of a polyamide RO device, since the RO film is also charged, the TOC
The effect of increasing the component blocking performance (removability) is also provided. As described above, the water treatment apparatus of the present invention promotes apparent ozone oxidation by the acid addition means, thereby suppressing fouling due to organic substances in the membrane, setting a high membrane filtration flux, and increasing the removal rate of the TOC component. Can be done.

【0011】そして、本発明の水処理装置は、比較的低
濃度の有機物を含有する水を処理して浄水、工業用水、
プロセス用水など清澄水を得るのに適し、例えば、河川
水、湖沼水、地下水などから飲料水や各種用水を製造す
る浄水装置として使用することができる。また、比較的
高濃度の有機物を含む下水、し尿、各種工場排水などの
汚水を生物的処理をして得られる生物処理水をさらに高
度処理して再利用水とする高度処理装置として使用する
ことができる。
[0011] The water treatment apparatus of the present invention treats water containing a relatively low concentration of organic matter to produce purified water, industrial water,
It is suitable for obtaining clear water such as process water, and can be used, for example, as a water purification device for producing drinking water and various types of water from river water, lake water, groundwater, and the like. In addition, the wastewater containing relatively high concentration of organic matter, human waste, and various types of industrial wastewater, etc., should be used as an advanced treatment device that treats biologically treated water obtained by biological treatment to make it more advanced and reused. Can be.

【0012】また、前記膜ろ過手段の前段にて凝集工程
を行うようにしても良い。即ち、原水に凝集剤を添加
し、凝集フロックを形成して膜ろ過しても良いし、添加
せずに膜ろ過しても良い。凝集剤を添加する方がより高
純度の処理水が得られる。この凝集工程は膜ろ過手段の
前段であれば任意の位置で実施すればよく、オゾン酸化
処理手段の前でも後でも良い。上述の凝集剤としては、
塩化鉄、硫酸鉄、塩化アルミニウム、硫酸アルミニウ
ム、酸化アルミニウム、ポリ塩化アルミニウムなど公知
の無機凝集剤を用いることができる。さらに、ポリアク
リルアミド系凝集剤などの高分子凝集剤を用いることも
できる。
[0012] Further, a coagulation step may be carried out before the membrane filtration means. That is, a coagulant may be added to raw water to form a flocculated floc and then subjected to membrane filtration, or may be subjected to membrane filtration without addition. Addition of a coagulant results in higher-purity treated water. This aggregation step may be performed at any position as long as it is before the membrane filtration means, and may be performed before or after the ozone oxidation treatment means. As the above flocculant,
Known inorganic coagulants such as iron chloride, iron sulfate, aluminum chloride, aluminum sulfate, aluminum oxide, and polyaluminum chloride can be used. Further, a polymer flocculant such as a polyacrylamide flocculant can be used.

【0013】尚、オゾン酸化処理手段に通水することに
より、TOC成分である高分子状のフミン酸やフルボ酸
が分解されると、カルボン酸等の生物分解が容易な成分
が生産されることになるので、これが膜ろ過手段を通過
し、後段のRO装置等の脱イオン処理手段で微生物汚染
を招くこともある。即ち、オゾン酸化手段により原水中
の微生物を殺菌処理したにもかかわらず、オゾン酸化処
理した処理水を膜ろ過して、脱イオン処理手段に導入し
ても、やはり上記のことが主因で脱イオン処理手段の薬
品洗浄頻度を長くできないということもある。
Incidentally, when water is passed through the ozone oxidation treatment means to decompose the polymeric humic acid or fulvic acid, which is a TOC component, components that are easily biodegradable such as carboxylic acid are produced. Therefore, this may pass through the membrane filtration means and cause microbial contamination in a deionization treatment means such as an RO device at the subsequent stage. That is, despite the microorganisms in the raw water being sterilized by the ozone oxidizing means, even if the treated water subjected to the ozone oxidizing treatment is subjected to membrane filtration and introduced into the deionizing treatment means, the deionized water is still mainly due to the above. In some cases, the frequency of chemical cleaning of the processing means cannot be increased.

【0014】このような場合には、脱イオン処理手段の
前段で還元剤を添加することにより、残留オゾンを還元
すると共に、脱イオン処理手段への供給水を還元雰囲気
とすることにより、微生物の増殖を抑えることができ
る。
In such a case, the residual ozone is reduced by adding a reducing agent in the preceding stage of the deionizing means, and the water supplied to the deionizing means is made to have a reducing atmosphere so that microorganisms can be reduced. Proliferation can be suppressed.

【0015】上述の還元剤を脱イオン処理手段の前段で
供給する手段としては、還元剤貯留タンクから薬注配
管、薬注ポンプを介して脱イオン処理手段の前に設けら
れる貯水槽に添加するようにしても良いし、脱イオン処
理手段への給水配管に注入するようにしてもよい。この
還元剤としては、チオ硫酸ナトリウム、重亜硫酸ナトリ
ウム、ヒドラジン等の中から採用するが、好ましくは重
亜硫酸ナトリウムを用いる。さらに、還元剤の添加量
は、残留オゾンを消去し、還元性雰囲気となるような量
とする。好ましくは、酸化還元電位(ORP)が負とな
るようにすればよく、ORP計を用いて還元剤添加量を
制御することができる。
As means for supplying the above-mentioned reducing agent at the preceding stage of the deionizing means, the reducing agent is added from a reducing agent storage tank to a water tank provided before the deionizing means via a chemical injection pipe and a chemical injection pump. Alternatively, the water may be injected into a water supply pipe to the deionization processing means. As this reducing agent, sodium thiosulfate, sodium bisulfite, hydrazine or the like is employed, but preferably sodium bisulfite is used. Further, the amount of the reducing agent added is such that residual ozone is eliminated and a reducing atmosphere is obtained. Preferably, the oxidation-reduction potential (ORP) should be negative, and the amount of the reducing agent added can be controlled using an ORP meter.

【0016】このように脱イオン処理手段に通水する膜
ろ過水に還元剤を添加する還元剤供給手段を設けた水処
理装置では、UF膜又はMF膜やRO膜等のの膜汚染が
抑止され、ろ過性能を向上させるだけでなく、処理シス
テム全体のTOC除去性能を高めるという効果ももたら
される。
As described above, in the water treatment apparatus provided with the reducing agent supply means for adding the reducing agent to the membrane filtered water passing through the deionizing means, the membrane contamination of the UF membrane, the MF membrane, the RO membrane, etc. is suppressed. This not only improves the filtration performance, but also has the effect of increasing the TOC removal performance of the entire processing system.

【0017】また、本発明の水処理装置としては、上述
の説明以外の工程を適宜に追加するようにしたものでも
よく、例えばシリカ分散剤を併用すれば、経済性を向上
させることもできる。
The water treatment apparatus of the present invention may be one in which steps other than those described above are added as appropriate. For example, if a silica dispersant is used in combination, the economic efficiency can be improved.

【0018】[0018]

【実施例】〔実施例〕図1に示すように原水に硫酸を加
えて(酸添加手段)pHを酸性にした後、オゾンを注入
し、酸化処理する手段(オゾン接触塔)を設け、その後
段にオゾン酸化処理水を膜ろ過する手段(MF膜)を設
け、さらにその後段に膜ろ過水に重亜硫酸ナトリウムを
添加(還元剤供給手段)した後、RO装置に通水する形
態の実施例である水処理装置により通水実験を行った。
上記のオゾン接触塔は向流接触方式(滞留時間:18m
in)とした。MF膜は四フッ化ポリエチレン(PTF
E)膜で、公称孔径0.2μmの平膜からなるスパイラ
ル形状の膜モジュール(栗田工業(株)株式会社製『K
M0212R』)を用いた。また、このエレメントは
7.5分間隔で処理水側に空気を押し込み逆洗するとと
もに原水側にも空気を導入し、エアスクラビングを行
い、MF膜面の汚れを系外に排出した。さらに、MF膜
ろ過水に還元剤として重亜硫酸ナトリウム5mg/lを
添加し、MF膜ろ過水に残留する溶存オゾンを除去する
と共に還元雰囲気にすることにより微生物の増殖を抑え
てRO装置に供給した。RO膜はポリアミド系の材質か
らなるスパイラル型モジュール(日東電工(株)製『E
S−10』)を採用した。実験に供した原水は水田地の
伏流水であり、低濁度であるがフミン質含有量が高いた
め、高色度、高TOCを示した。
EXAMPLE [Example] As shown in FIG. 1, sulfuric acid was added to raw water (acid adding means) to make the pH acidic, then ozone was injected, and means for oxidizing treatment (ozone contact tower) was provided. An embodiment in which a means (MF membrane) for membrane filtration of ozone oxidized water is provided in the stage, and sodium bisulfite is added to the membrane filtered water (reducing agent supply means) in the subsequent stage, and then water is passed through the RO device A water-passing experiment was performed using a water treatment device.
The above ozone contact tower is a countercurrent contact type (residence time: 18 m
in). The MF membrane is made of polyethylene tetrafluoride (PTF
E) Spiral membrane module consisting of a flat membrane with a nominal pore diameter of 0.2 μm (Kurita Kogyo Co., Ltd. “K
M0212R ") was used. In addition, air was pushed into the treated water side at 7.5 minute intervals to backwash the element, and air was also introduced into the raw water side, air scrubbing was performed, and dirt on the MF membrane surface was discharged out of the system. Furthermore, 5 mg / l of sodium bisulfite was added as a reducing agent to the MF membrane filtrate to remove dissolved ozone remaining in the MF membrane filtrate and to reduce the microorganisms by reducing the atmosphere to supply the RO water to the RO apparatus. . The RO film is a spiral type module made of polyamide-based material ("E" manufactured by Nitto Denko Corporation).
S-10 "). The raw water used in the experiment was underground water in a paddy field and had high chromaticity and high TOC because of low turbidity but high humic substance content.

【0019】〔比較例1,2〕オゾンを添加しない以外
は前記実施例と同様にしたものを比較例1とし、酸を添
加しない以外は前記実施例と同様にしたものを比較例2
とした。
[Comparative Examples 1 and 2] Comparative Example 1 was the same as the above-mentioned Example except that ozone was not added, and Comparative Example 2 was the same as the above-mentioned Example except that no acid was added.
And

【0020】〔通水条件〕前記実施例及び比較例1,2
の水処理装置における通水条件を以下の表1に整理し
た。
[Water flow conditions] The above embodiment and comparative examples 1 and 2
Table 1 below summarizes the water flow conditions in the water treatment device of No.

【表1】 [Table 1]

【0021】〔通水試験結果1;MF膜のろ過安定性〕
前記通水条件にて3〜5日の連続通水を行い、1日1回
実施したエアスクラビング後の膜差圧からその差圧速度
上昇速度を求め、MF膜のろ過安定性を評価した。この
結果を表2に示した。
[Water flow test result 1; Filtration stability of MF membrane]
Water was continuously passed for 3 to 5 days under the above-mentioned water passing conditions, and the rate of increase in the differential pressure speed was determined from the membrane differential pressure after air scrubbing performed once a day, and the filtration stability of the MF membrane was evaluated. The results are shown in Table 2.

【表2】 上表2より明らかなように、原水に酸を添加してオゾン
酸化処理し、さらに膜ろ過水中に残留オゾンが検出され
る条件で通水した本発明の実施例では、膜ろ過流束が
5.0m/dという高流束でも膜差圧上昇速度が極めて
低く、安定した通水が可能であることが確認された。こ
れに対し、オゾンを注入しなかった比較例1では、膜差
圧上昇速度が極めて高く、この運転を継続すれば2〜4
週間に1回の高頻度で薬品洗浄する必要が生じることが
確認された。さらに、オゾンを注入したものの酸を添加
しなかった比較例2では、実施例ほどではないものの膜
差圧上昇速度が低いため安定な通水が可能であった。
[Table 2] As is clear from Table 2 above, in the embodiment of the present invention in which the raw water was subjected to ozone oxidation treatment by adding an acid, and further the water was passed under the condition that residual ozone was detected in the membrane filtration water, the membrane filtration flux was 5%. Even at a high flux of 0.0 m / d, the rate of increase in the membrane differential pressure was extremely low, and it was confirmed that stable water flow was possible. On the other hand, in Comparative Example 1 in which ozone was not injected, the membrane differential pressure increasing rate was extremely high.
It was confirmed that chemical cleaning needs to be performed once a week at a high frequency. Furthermore, in Comparative Example 2 in which ozone was injected but no acid was added, although not as high as in the example, the rate of rise in the membrane differential pressure was low, so that stable water flow was possible.

【0022】〔通水試験結果2;MF膜ろ過水のTOC
と除去率〕連続通水期間の原水TOC、MF膜ろ過水の
TOCを測定し、その結果を表3に示した。また、MF
膜によるTOC除去率を算出し、併せて示した。
[Water flow test result 2: TOC of MF membrane filtered water]
And removal rate] The raw water TOC and the TOC of the MF membrane filtered water during the continuous water flow period were measured. The results are shown in Table 3. Also, MF
The TOC removal rate by the membrane was calculated and shown together.

【表3】 上表3より明らかなように、原水に酸を添加してオゾン
酸化処理し、さらに膜ろ過水中に残留オゾンが検出され
る条件で通水した本発明の実施例では、MF膜によるT
OC除去率は63%と高い値を示し、後段のROの負担
を軽減することが確認された。これに対し、オゾンを注
入しなかった比較例1では、TOCの除去性は殆ど認め
られなかった。さらに、オゾンを注入したものの酸を添
加しなかった比較例2では、TOC除去率は比較例1よ
りは高くオゾン注入の効果が認められたが、実施例に比
べると明らかに差異が認められ、TOC除去率が低かっ
た。
[Table 3] As is clear from Table 3 above, in the embodiment of the present invention in which the raw water was subjected to ozone oxidation treatment by adding an acid, and furthermore, water was passed under the condition that residual ozone was detected in the membrane filtered water, the T
The OC removal rate was as high as 63%, and it was confirmed that the burden on the RO at the subsequent stage was reduced. On the other hand, in Comparative Example 1 in which ozone was not injected, TOC removal was hardly recognized. Furthermore, in Comparative Example 2 in which ozone was injected but no acid was added, the TOC removal rate was higher than that of Comparative Example 1 and the effect of ozone injection was recognized, but a clear difference was recognized as compared with the Example. The TOC removal rate was low.

【0023】〔通水試験結果3;RO透過水のTOCと
除去率〕連続通水期間のMF膜ろ過水、RO透過水のT
OCを測定し、その結果を表4に示した。また、ROに
よるTOC除去率を算出し、併せて示した。
[Permeation test result 3: TOC and removal rate of RO permeated water] T of MF membrane filtered water and RO permeated water during continuous water passage
The OC was measured, and the results are shown in Table 4. The TOC removal rate by RO was calculated and shown together.

【表4】 上記表4より明らかなように、原水に酸を添加してオゾ
ン酸化処理し、さらに膜ろ過水中に残留オゾンが検出さ
れる条件で通水した本発明の実施例では、RO透過水の
TOCは0.035mg/lの極めて低い値を示し、
0.05mg/l以下の水質を得る高度処理が可能なこ
とが確認された。これに対し、オゾンを注入しなかった
比較例1やオゾンを注入したものの酸を添加しなかった
比較例2では、ROにおけるTOC除去率では実施例と
近い数値が得られているが、実施例のような高水質が得
られなかった。以上の実験結果より、RO等の脱イオン
処理手段の前処理にオゾン酸化処理手段とMF膜等の膜
ろ過手段を導入し、さらにオゾン酸化処理手段に際して
は酸添加することにより、膜ろ過手段及び脱イオン処理
手段が安定して運転できること及びTOC除去率が高く
なることが確認された。
[Table 4] As is clear from Table 4 above, in the embodiment of the present invention in which the raw water was subjected to ozone oxidation treatment by adding an acid, and furthermore, water was passed under conditions where residual ozone was detected in the membrane filtration water, the TOC of the RO permeated water was Showing a very low value of 0.035 mg / l,
It was confirmed that advanced treatment for obtaining a water quality of 0.05 mg / l or less was possible. On the other hand, in Comparative Example 1 in which ozone was not injected and in Comparative Example 2 in which ozone was injected but no acid was added, the TOC removal rate in RO was close to that of the Example, but the Example High water quality such as was not obtained. From the above experimental results, the ozone oxidation treatment means and the membrane filtration means such as MF membrane were introduced into the pretreatment of the deionization treatment means such as RO, and the ozone oxidation treatment means was further added with an acid, so that the membrane filtration means and It was confirmed that the deionization processing means can be operated stably and the TOC removal rate is high.

【0024】[0024]

【発明の効果】以上詳述した通り、本発明の水処理装置
によれば、オゾン酸化処理を酸添加による酸性条件下に
て行うことにより、原水中のTOC成分である高分子状
のフミン酸やフルボ酸を酸化分解し、膜ろ過手段及び脱
イオン処理手段にて容易に除去することができる。ま
た、オゾン酸化処理により有機成分が分解して低分子化
され、荷電状態のTOC成分を増加するので、ポリアミ
ド系の逆浸透膜のように荷電性の脱イオン処理手段で
は、それらのTOC成分の阻止性が高まる。したがっ
て、本発明の水処理装置は、膜ろ過手段における有機物
汚染を抑制すると共にTOC成分の除去性を高め、膜ろ
過流束を高く設定することができ、脱イオン処理手段の
負担を軽減することもできる。その結果、安定に運転
(稼働)できると共にTOC成分の除去性能を向上する
ことができ、特に高度な除去率が要求される超純水製造
にも複雑なシステムを必要とすることなく容易に適用す
ることができる。そして、本発明の水処理装置は、比較
的低濃度の有機物を含有する水を処理して浄水、工業用
水、プロセス用水など清澄水を得るのに適し、例えば河
川水、湖沼水、地下水などから飲料水や各種用水を製造
する浄水装置として使用でき、また、比較的高濃度の有
機物を含む下水、し尿、各種工場排水などの汚水を生物
的処理をして得られる生物処理水をさらに高度処理して
再利用水とする高度処理装置として使用することができ
る。また、特に脱イオン処理手段に通水する膜ろ過水に
還元剤を添加する還元剤供給手段を設けた場合、脱イオ
ン処理手段への供給水が還元雰囲気となり、微生物の増
殖を抑えることができる。その結果、薬品洗浄頻度を低
く(=薬品洗浄間隔を長く)することができ、脱イオン
処理手段の運転効率を向上させることができる。
As described in detail above, according to the water treatment apparatus of the present invention, the ozone oxidation treatment is performed under acidic conditions by adding an acid, so that the polymeric humic acid as the TOC component in the raw water is obtained. And fulvic acid can be oxidatively decomposed and easily removed by membrane filtration means and deionization treatment means. In addition, since the organic components are decomposed into lower molecules by the ozone oxidation treatment and the charged TOC component is increased, the charged deionization treatment means such as a polyamide-based reverse osmosis membrane can reduce such TOC components. Deterrence increases. Therefore, the water treatment apparatus of the present invention can suppress the organic substance contamination in the membrane filtration means, enhance the removability of the TOC component, set the membrane filtration flux high, and reduce the load on the deionization treatment means. Can also. As a result, it is possible to stably operate (operate) and improve the TOC component removal performance, and it can be easily applied without particularly a complicated system to ultrapure water production requiring a high removal rate. can do. And the water treatment apparatus of the present invention is suitable for treating clear water such as purified water, industrial water, and process water by treating water containing a relatively low concentration of organic matter, for example, from river water, lake water, groundwater, and the like. It can be used as a water purification device for producing drinking water and various types of water, and further advanced treatment of biologically treated water obtained by biologically treating sewage, human waste, and various factory wastewater containing relatively high concentrations of organic matter. It can be used as an advanced treatment device to make recycled water. In particular, in the case where a reducing agent supply unit for adding a reducing agent to the membrane filtration water passing through the deionizing unit is provided, the water supplied to the deionizing unit becomes a reducing atmosphere, and the growth of microorganisms can be suppressed. . As a result, the frequency of chemical cleaning can be reduced (= the chemical cleaning interval is lengthened), and the operation efficiency of the deionization processing means can be improved.

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

【図1】本発明の水処理装置の一実施例を示すフロー
(流れ系統図)である。
FIG. 1 is a flow (flow system diagram) showing one embodiment of a water treatment apparatus of the present invention.

───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 FI テーマコート゛(参考) C02F 1/44 C02F 1/44 K 1/70 1/70 Z Fターム(参考) 4D006 GA03 GA06 GA07 HA61 KA02 KA03 KA31 KA33 KA43 KA52 KA53 KA55 KA57 KA71 KB13 KB21 KB30 KC03 KC13 KC14 KD02 KD08 KD11 KD21 KE05P KE06P KE11Q KE12P KE13P KE15Q KE30Q MA01 MA02 MA03 MA22 MC03 MC29 MC30X MC54X PA01 PB04 PB05 PB08 PB24 PB70 4D050 AA02 AA03 AA17 AB07 AB16 AB17 BA06 BA07 BA09 BB02 BD02 BD06 BD08 CA09 CA10 CA13 CA16 ──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. 7 Identification symbol FI theme coat ゛ (reference) C02F 1/44 C02F 1/44 K 1/70 1/70 Z F term (reference) 4D006 GA03 GA06 GA07 GA07 HA61 KA02 KA03 KA31 KA33 KA43 KA52 KA53 KA55 KA57 KA71 KB13 KB21 KB30 KC03 KC13 KC14 KD02 KD08 KD11 KD21 KE05P KE06P KE11Q KE12P KE13P BA KE15Q KE30Q MA01 MA02 MA03 MA02 P03 MC05 P03 MC03 MC01 MC03 BB02 BD02 BD06 BD08 CA09 CA10 CA13 CA16

Claims (2)

    【特許請求の範囲】[Claims]
  1. 【請求項1】 原水をオゾン酸化するオゾン酸化処理手
    段と、オゾン酸化処理された水を通水して水中の懸濁物
    質、不溶性物質を分離除去する膜ろ過手段と、膜ろ過水
    を脱イオン処理する脱イオン処理手段とを備えた水処理
    装置において、前記オゾン酸化処理手段の前段又は/及
    びオゾン酸化処理手段に酸添加手段を設けたことを特徴
    とする水処理装置。
    1. Ozone oxidation treatment means for oxidizing raw water with ozone, membrane filtration means for passing ozone-oxidized water through to separate suspended substances and insoluble substances in water, and deionizing membrane filtered water A water treatment apparatus provided with a deionization treatment means for treating, wherein an acid addition means is provided before the ozone oxidation treatment means and / or in the ozone oxidation treatment means.
  2. 【請求項2】 脱イオン処理手段に通水する膜ろ過水に
    還元剤を添加する還元剤供給手段を設けたことを特徴と
    する請求項1記載の水処理装置。
    2. The water treatment apparatus according to claim 1, further comprising a reducing agent supply unit for adding a reducing agent to the membrane filtration water flowing through the deionization processing unit.
JP2000001392A 2000-01-07 2000-01-07 Water treating apparatus Granted JP2001191086A (en)

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Publication Number Publication Date
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Family

ID=18530628

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Country Link
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JP2003265935A (en) * 2002-03-15 2003-09-24 Suido Kiko Kaisha Ltd Membrane filtration module cleaning method, membrane filtration apparatus, and chemical-used cleaning apparatus
JP2004136183A (en) * 2002-10-16 2004-05-13 Fuji Electric Systems Co Ltd Water treatment method and apparatus therefor
JP2004141738A (en) * 2002-10-23 2004-05-20 Ngk Insulators Ltd Method of modifying membrane-treated water
JP2005324118A (en) * 2004-05-14 2005-11-24 Kurita Water Ind Ltd Method and apparatus for treating water
JP2006263640A (en) * 2005-03-25 2006-10-05 Ngk Insulators Ltd Method for producing pure water by using ceramic membrane
JP2007203249A (en) * 2006-02-03 2007-08-16 Kurita Water Ind Ltd Water treating apparatus and method
JP2007524500A (en) * 2003-04-11 2007-08-30 コスロウ テクノロジーズ コーポレーション Microporous filter media with safe features
JP2007245001A (en) * 2006-03-16 2007-09-27 Ngk Insulators Ltd Water cleaning method
JP2007245003A (en) * 2006-03-16 2007-09-27 Ngk Insulators Ltd Seawater desalination method
KR101420063B1 (en) * 2013-12-30 2014-07-17 주식회사 한화건설 a treated wastewater recycling system using both ozone treated back washing water and the inorganic memberane and the treated wastewater recycling method
JP2016073902A (en) * 2014-10-03 2016-05-12 栗田工業株式会社 Method and apparatus for electric deionization treatment of vanadium-containing water
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JP2016073902A (en) * 2014-10-03 2016-05-12 栗田工業株式会社 Method and apparatus for electric deionization treatment of vanadium-containing water
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