JP6088378B2 - Selenium-containing water treatment method and selenium-containing water treatment apparatus - Google Patents
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Description
本発明は、セレン含有水中に含まれるセレン酸イオンおよび亜セレン酸イオンのうち少なくとも１つを除去するセレン含有水の処理方法および処理装置に関する。 The present invention relates to a method and an apparatus for treating selenium-containing water that remove at least one of selenate ions and selenite ions contained in selenium-containing water.
セレン含有水中において、セレンは通常、セレン酸イオン（ＳｅＯ4 2-：６価セレン）または亜セレン酸イオン（ＳｅＯ3 2-：４価セレン）の形態で溶存している。なお、これらのイオンがセレン含有水中に単独で存在することもあるが、通常は、両者が共存している場合が多い。 In selenium-containing water, selenium is usually dissolved in the form of selenate ion (SeO 4 2− : hexavalent selenium) or selenite ion (SeO 3 2− : tetravalent selenium). These ions may be present alone in the selenium-containing water, but usually both of them coexist in many cases.
従来、セレン含有水中に含まれるセレン酸イオンおよび亜セレン酸イオンのうち少なくとも１つ（以下、これらを「溶解性セレン」ということもある）を除去する方法として、下記（１）から（３）の物理化学的処理方法や、（４）の生物学的処理方法等が知られている。 Conventionally, as a method of removing at least one of selenate ions and selenite ions contained in selenium-containing water (hereinafter sometimes referred to as “soluble selenium”), the following (1) to (3) The physicochemical treatment method of (4) and the biological treatment method of (4) are known.
（１）セレン含有水中に含まれる溶解性セレンを樹脂等から構成される吸着材により吸着して除去する方法。
（２）セレン含有水にマグネシウム塩、亜鉛塩、第２鉄塩等の金属塩を添加して、セレンをこれら金属塩との不溶性セレン化合物として分離除去する方法。
（３）溶解性セレンを不溶性の分子状セレン（０価セレン）に還元することができる第１鉄塩をセレン含有水に添加して、溶解性セレンを不溶化した後、生成した不溶化物を沈殿等によって分離除去する方法。
（４）セレン含有水中に含まれる溶解性セレンを通性嫌気性条件（溶存酸素が実質的に存在しない条件）下での嫌気性生物処理によって不溶性の分子状セレンに還元した後、この分子状セレンを微生物に吸着させて微生物と共に分離したり、分子状セレン自体を沈降分離等により分離除去する方法。この方法では、セレン酸イオンはいったん亜セレン酸イオンに還元された後に分子状セレンに還元され、亜セレン酸イオンは分子状セレンに直接還元されると考えられる。
(1) A method in which soluble selenium contained in selenium-containing water is adsorbed and removed by an adsorbent composed of a resin or the like.
(2) A method in which a metal salt such as magnesium salt, zinc salt or ferric salt is added to selenium-containing water, and selenium is separated and removed as an insoluble selenium compound with these metal salts.
(3) A ferrous salt capable of reducing soluble selenium to insoluble molecular selenium (zero-valent selenium) is added to selenium-containing water to insolubilize soluble selenium, and then the insoluble matter produced is precipitated. A method of separating and removing by etc.
(4) Soluble selenium contained in selenium-containing water is reduced to insoluble molecular selenium by anaerobic biological treatment under aerobic anaerobic conditions (conditions in which dissolved oxygen is substantially absent). A method in which selenium is adsorbed by a microorganism and separated together with the microorganism, or molecular selenium itself is separated and removed by sedimentation separation or the like. In this method, it is considered that selenate ions are once reduced to selenite ions and then reduced to molecular selenium, and selenite ions are directly reduced to molecular selenium.
しかしながら、前述した（１）から（３）の方法は、それぞれ次のような問題点を有するものであった。 However, the methods (1) to (3) described above have the following problems.
（１）の吸着法では、処理の良否が共存物質の影響を受けやすく、また吸着材の再生廃液中に含まれる溶解性セレンの処理が問題となる。 In the adsorption method (1), the quality of the treatment is easily influenced by coexisting substances, and the treatment of soluble selenium contained in the adsorbent regeneration waste liquid becomes a problem.
（２）の化学的処理法では、４価の亜セレン酸イオンからは不溶性セレン化合物が比較的容易に生成するが、６価のセレン酸イオンからは不溶性セレン化合物が生成しにくく、そのため６価のセレン酸イオンが処理水中に残存し、その結果、全セレン濃度を排水基準値である０．１ｍｇ−Ｓｅ／Ｌ以下にまで除去することが難しかった。 In the chemical treatment method (2), insoluble selenium compounds are relatively easily formed from tetravalent selenite ions, but insoluble selenium compounds are hardly formed from hexavalent selenate ions. As a result, it was difficult to remove the total selenium concentration to 0.1 mg-Se / L or less, which is the wastewater standard value.
（３）の化学的処理法では、セレン酸イオンおよび亜セレン酸イオンの両方を除去することが可能であるが、この方法では第１鉄塩を多量に必要とするとともに、固液分離後の不溶化物（汚泥）が多量に発生するため、ランニングコスト、廃棄物処理コスト等の点で不利であった。 In the chemical treatment method (3), it is possible to remove both selenate ions and selenite ions, but this method requires a large amount of ferrous salt, and after solid-liquid separation. Since a large amount of insolubilized material (sludge) was generated, it was disadvantageous in terms of running cost, waste disposal cost, and the like.
また、これら物理化学的処理方法の共通の問題点としては、処理対象物質（この場合は溶解性セレンを指す）が高濃度の場合と比較して、低濃度の場合には反応効率が低下するという一般的な化学反応の性質から、高濃度の溶解性セレンを含むセレン含有水を処理してセレン濃度を低濃度にまで低減するためには、吸着材や凝集剤の量を増やしたり、反応効率を上げるために多段式処理にしたりする必要があり、コストが非常に高くなることがあった。 In addition, a common problem with these physicochemical treatment methods is that the reaction efficiency decreases when the concentration of the substance to be treated (in this case, soluble selenium) is low compared to when the concentration is high. In order to reduce the selenium concentration to a low concentration by treating selenium-containing water containing a high concentration of soluble selenium, the amount of adsorbent and flocculant can be increased or the reaction In order to increase the efficiency, it is necessary to use a multistage process, and the cost may become very high.
（４）の生物学的処理方法では、セレン含有水と生物とを接触させ、溶解性セレンを生物の働きにより不溶性の分子状セレンに還元して、分離除去する。類似の例としては生物脱窒や生物脱硫があり、例えば脱窒菌は、通性嫌気条件（溶存酸素が実質的に存在しない条件）において、水素供与体としての有機物（例えばメタノール等）の存在下で、硝酸性窒素（ＮＯ3 -）および亜硝酸性窒素（ＮＯ2 -）のうち少なくとも１つの結合酸素（ＮＯ3のＯ、ＮＯ2のＯ）を利用して呼吸を行い、硝酸性窒素および亜硝酸性窒素のうち少なくとも１つを還元して窒素ガス化することにより、排水中の窒素を除去する。セレン還元菌も、脱窒菌と同様に、通性嫌気条件および水素供与体存在下において、セレン酸イオンおよび亜セレン酸イオンのうち少なくとも１つの結合酸素（ＳｅＯ4 2-のＯ、ＳｅＯ3 2-のＯ）を利用して呼吸を行うことにより、セレン酸イオンおよび亜セレン酸イオンのうち少なくとも１つを分子状セレンに還元すると考えられる。 In the biological treatment method (4), selenium-containing water is contacted with a living organism, and soluble selenium is reduced to insoluble molecular selenium by the action of the living organism and separated and removed. Similar examples include biological denitrification and biological desulfurization. For example, denitrifying bacteria can be used in the presence of organic substances (such as methanol) as hydrogen donors under facultative anaerobic conditions (conditions in which dissolved oxygen is substantially absent). And breathing using at least one combined oxygen (NO 3 O, NO 2 O) of nitrate nitrogen (NO 3 − ) and nitrite nitrogen (NO 2 − ), and nitrate nitrogen and Nitrogen in the waste water is removed by reducing at least one of the nitrite nitrogens into nitrogen gas. Similarly to denitrifying bacteria, selenium-reducing bacteria can also bind to at least one bound oxygen (SeO 4 2− O, SeO 3 2−) among selenate ions and selenite ions under facultative anaerobic conditions and in the presence of a hydrogen donor. It is considered that at least one of selenate ion and selenite ion is reduced to molecular selenium by performing respiration using O).
（４）の生物学的処理方法では、亜セレン酸イオンと共に、物理化学的方法では除去が困難であるセレン酸イオンを除去することができ、したがって溶解性セレンの大部分を毒性の弱い分子状セレンにできるという利点がある。しかし、この生物学的処理方法では、酸化還元電位（ＯＲＰ）を−５０ｍＶ以下にする必要があった（例えば、特許文献１参照）。酸化還元電位が０の場合でも嫌気状態であって、脱窒等の生物汚泥の本来の機能は現われるが、溶解性セレンの還元はほとんど起こらない。したがって、脱窒等が起こるよりもはるかに強い嫌気度とすることにより、溶解性セレンの還元が可能になる。 In the biological treatment method (4), selenate ions, which are difficult to remove by physicochemical methods, can be removed together with selenite ions. There is an advantage that selenium can be made. However, in this biological treatment method, the redox potential (ORP) needs to be −50 mV or less (see, for example, Patent Document 1). Even when the oxidation-reduction potential is 0, it is in an anaerobic state, and the original functions of biological sludge such as denitrification appear, but the reduction of soluble selenium hardly occurs. Therefore, it is possible to reduce soluble selenium by making the anaerobic degree much stronger than denitrification or the like.
酸化還元電位を−５０ｍＶ以下にする方法としては、例えば、有機物の添加量およびセレン含有水の滞留時間のうち少なくとも１つを制御する方法がある。有機物は基質として添加されるもので、通常メタノール等が用いられるが、有機排水等の他の有機物源であってもよい。このような有機物添加量を多くすると酸化還元電位は低くなり、嫌気度が高くなるが、有機物の添加量が反応等量よりも過剰となることがある。 As a method of setting the oxidation-reduction potential to −50 mV or less, for example, there is a method of controlling at least one of the addition amount of organic matter and the residence time of selenium-containing water. The organic substance is added as a substrate, and methanol or the like is usually used, but other organic substance sources such as organic waste water may be used. Increasing the amount of organic matter added decreases the oxidation-reduction potential and increases the anaerobic degree, but the amount of organic matter added may be more than the reaction equivalent.
セレン含有水の滞留時間を制御する方法では、セレン含有水の導入量を少なくすることにより滞留時間を長くすると、酸化還元電位が低下し、嫌気度が高くなる。そのため、特許文献１の方法では、滞留時間を１２時間から２４時間以上と長大にとる必要があった。この場合、滞留時間を長くするには反応槽を大きくする必要が生じ、装置建設コストが大きくなるデメリットがある。 In the method of controlling the residence time of selenium-containing water, if the residence time is lengthened by reducing the amount of selenium-containing water introduced, the oxidation-reduction potential decreases and the anaerobic degree increases. Therefore, in the method of Patent Document 1, the residence time needs to be as long as 12 hours to 24 hours or more. In this case, in order to lengthen the residence time, it is necessary to enlarge the reaction tank, and there is a demerit that the apparatus construction cost increases.
また、セレン含有水中に硫酸塩が存在する場合、酸化還元電位が低下しすぎると硫酸還元により硫化水素が生じるので、脱硫設備を設ける必要が生じる。 In addition, when sulfate is present in the selenium-containing water, if the oxidation-reduction potential is too low, hydrogen sulfide is generated due to sulfate reduction, so that it is necessary to provide a desulfurization facility.
本発明の目的は、生物学的処理方法を利用するセレン含有水の処理において、溶解性セレンを効率的に除去することができるセレン含有水の処理方法および処理装置を提供することにある。 An object of the present invention is to provide a method and an apparatus for treating selenium-containing water that can efficiently remove soluble selenium in the treatment of selenium-containing water using a biological treatment method.
本発明は、滞留時間を１２時間未満に制御して、セレン含有水を通性嫌気性条件下および有機物の存在下で多孔質の流動担体に保持された生物汚泥と接触させる生物処理工程を含み、前記流動担体は、粒径３ｍｍ以上５ｍｍ以下、比重０．１以上１．２以下の親水性のポリビニルアルコール担体である、セレン含有水の処理方法である。 The present invention includes a biological treatment step in which the residence time is controlled to be less than 12 hours, and the selenium-containing water is contacted with biological sludge held on a porous fluid carrier under the conditions of permeable and anaerobic conditions and in the presence of organic matter. The fluid carrier is a method for treating selenium-containing water , which is a hydrophilic polyvinyl alcohol carrier having a particle size of 3 mm to 5 mm and a specific gravity of 0.1 to 1.2 .
前記セレン含有水の処理方法において、前記セレン含有水の全セレン濃度が、０．１〜２．０ｍｇ−Ｓｅ／Ｌの範囲であることが好ましい。 In the method for treating selenium-containing water, the total selenium concentration of the selenium-containing water is preferably in the range of 0.1 to 2.0 mg-Se / L.
前記セレン含有水の処理方法において、前記セレン含有水が、石炭火力発電所脱硫排水であることが好ましい。 In the method for treating selenium-containing water, the selenium-containing water is preferably coal-fired power plant desulfurization effluent.
また、本発明は、滞留時間を１２時間未満に制御して、セレン含有水を通性嫌気性条件下および有機物の存在下で多孔質の流動担体に保持された生物汚泥と接触させる生物処理手段を備え、前記流動担体は、粒径３ｍｍ以上５ｍｍ以下、比重０．１以上１．２以下の親水性のポリビニルアルコール担体である、セレン含有水の処理装置である。 The present invention also provides a biological treatment means for controlling the residence time to be less than 12 hours and bringing the selenium-containing water into contact with the biological sludge held on the porous fluid carrier under the condition of permeable and anaerobic conditions and in the presence of organic matter. wherein the flow carrier, the particle size 3mm or 5mm or less, Ru polyvinyl alcohol carrier der specific gravity 0.1 to 1.2 hydrophilic is a processing apparatus selenium-containing water.
前記セレン含有水の処理装置において、前記セレン含有水の全セレン濃度が、０．１〜２．０ｍｇ−Ｓｅ／Ｌの範囲であることが好ましい。 In the selenium-containing water treatment apparatus, the total selenium concentration of the selenium-containing water is preferably in the range of 0.1 to 2.0 mg-Se / L.
前記セレン含有水の処理装置において、前記セレン含有水が、石炭火力発電所脱硫排水であることが好ましい。 In the selenium-containing water treatment apparatus, it is preferable that the selenium-containing water is a coal-fired power plant desulfurization effluent.
本発明では、生物学的処理方法を利用するセレン含有水の処理において、滞留時間を１２時間未満に制御して、セレン含有水を通性嫌気性条件下および有機物の存在下で多孔質の流動担体に保持された生物汚泥と接触させることにより、溶解性セレンを効率的に除去することができる。 In the present invention, in the treatment of selenium-containing water using a biological treatment method, the residence time is controlled to be less than 12 hours, and the selenium-containing water is subjected to porous flow under anaerobic conditions and in the presence of organic substances. Soluble selenium can be efficiently removed by contacting with biological sludge held on a carrier.
本発明の実施の形態について以下説明する。本実施形態は本発明を実施する一例であって、本発明は本実施形態に限定されるものではない。 Embodiments of the present invention will be described below. This embodiment is an example for carrying out the present invention, and the present invention is not limited to this embodiment.
本発明の実施形態に係るセレン含有水処理装置の一例の概略を図１に示し、その構成について説明する。図１に示すセレン含有水処理装置１は、多孔質の担体が充填された嫌気性反応槽１０を備える。図１のセレン含有水処理装置１において、嫌気性反応槽１０の入口には原水配管２２が接続され、出口には生物処理水配管２４が接続されている。嫌気性反応槽１０には、担体を流動させるための撹拌手段として撹拌羽根等を有する撹拌装置１４が設置されている。また、嫌気性反応槽１０には、酸化還元電位測定手段として酸化還元電位測定装置１２が設置され、有機物供給手段として有機物供給槽１６がポンプ１８を介して有機物配管２６により接続されている。酸化還元電位測定装置１２とポンプ１８とには有機物供給量制御装置２０が電気的接続手段等により接続されていてもよい。 An outline of an example of a selenium-containing water treatment apparatus according to an embodiment of the present invention is shown in FIG. A selenium-containing water treatment apparatus 1 shown in FIG. 1 includes an anaerobic reaction tank 10 filled with a porous carrier. In the selenium-containing water treatment apparatus 1 of FIG. 1, a raw water pipe 22 is connected to the inlet of the anaerobic reaction tank 10, and a biological treated water pipe 24 is connected to the outlet. The anaerobic reaction tank 10 is provided with a stirring device 14 having stirring blades and the like as stirring means for flowing the carrier. In the anaerobic reaction tank 10, a redox potential measuring device 12 is installed as a redox potential measuring means, and an organic substance supply tank 16 is connected as an organic substance supplying means via an organic pipe 26 via a pump 18. An organic substance supply amount control device 20 may be connected to the oxidation-reduction potential measuring device 12 and the pump 18 by an electrical connection means or the like.
本実施形態に係るセレン含有水処理方法およびセレン含有水処理装置１の動作について説明する。 The operation of the selenium-containing water treatment method and the selenium-containing water treatment apparatus 1 according to this embodiment will be described.
セレン酸イオンおよび亜セレン酸イオンのうち少なくとも１つ（溶解性セレン）を含む原水であるセレン含有水は必要に応じて原水槽へ貯留された後、原水配管２２を通して、多孔質の担体が充填された流動床式等の嫌気性反応槽１０へ供給される。嫌気性反応槽１０において、撹拌装置１４により内容物が撹拌されながら、多孔質の担体に付着、保持されたセレン酸還元菌等の生物汚泥によりセレン含有水中に含まれる溶解性セレンが不溶性の分子状セレンに還元される（生物処理工程）。嫌気性反応槽１０へ有機物貯槽１６からポンプ１８により有機物配管２６を通して有機物が供給されて、また、嫌気性反応槽１０の滞留時間が１２時間未満に制御されて、嫌気性反応槽１０内の酸化還元電位（ＯＲＰ）が所定の範囲に調整される。嫌気性反応槽１０内の酸化還元電位は酸化還元電位測定装置１２により測定され、測定された酸化還元電位値に基づき、制御装置２０によりポンプ１８が制御されて、有機物の供給量が調整されてもよい。また、測定された酸化還元電位値に基づき、制御装置２０により原水の供給量が調整されてもよい。生物処理された生物処理水は、生物処理水配管２４を通して処理水として排出される。 Selenium-containing water, which is raw water containing at least one of selenate ion and selenite ion (soluble selenium), is stored in the raw water tank as necessary, and then filled with a porous carrier through the raw water pipe 22 Is supplied to the anaerobic reaction tank 10 such as a fluidized bed type. In the anaerobic reaction tank 10, while the contents are stirred by the stirring device 14, the soluble selenium contained in the selenium-containing water is insoluble due to the biological sludge such as selenate-reducing bacteria attached and held on the porous carrier. Is reduced to gaseous selenium (biological treatment process). The organic matter is supplied from the organic matter storage tank 16 to the anaerobic reaction tank 10 by the pump 18 through the organic pipe 26, and the residence time of the anaerobic reaction tank 10 is controlled to be less than 12 hours, so that the oxidation in the anaerobic reaction tank 10 is performed. The reduction potential (ORP) is adjusted to a predetermined range. The oxidation-reduction potential in the anaerobic reaction tank 10 is measured by the oxidation-reduction potential measuring device 12, and the pump 18 is controlled by the control device 20 based on the measured oxidation-reduction potential value to adjust the supply amount of organic matter. Also good. Moreover, the supply amount of raw water may be adjusted by the control device 20 based on the measured oxidation-reduction potential value. Biologically treated biologically treated water is discharged as treated water through the biologically treated water piping 24.
本発明者らは、嫌気条件を必要とするセレン還元菌をいかに嫌気性反応槽１０内で効率的に働かせることができるか鋭意検討した結果、嫌気性反応槽１０における滞留時間を１２時間未満に制御して、多孔質の担体にセレン還元菌を含む生物汚泥を付着させ、流動状態で反応させることにより、低濃度の溶解性セレンであっても短時間で効率的に処理可能であることを見出した。また、嫌気性反応槽１０内での酸化還元電位が０ｍＶ以上となる条件でも、セレン濃度を全セレンとして例えば０．２ｍｇ−Ｓｅ／Ｌ以下に安定して低減することが可能であることを見出した。その機構は定かではないが、多孔質の担体表面に発達した生物膜内部に局所的に嫌気部が存在し、生物膜内でセレン還元反応が生じており、この担体が流動することによってセレン含有水との接触効率が高められ、効率的なセレン還元反応を支えていると考えられる。 As a result of earnestly examining how selenium-reducing bacteria that require anaerobic conditions can be efficiently operated in the anaerobic reaction tank 10, the inventors have made the residence time in the anaerobic reaction tank 10 less than 12 hours. By controlling and attaching biological sludge containing selenium-reducing bacteria to a porous carrier and reacting it in a fluidized state, it is possible to treat even low-concentration soluble selenium efficiently in a short time. I found it. Further, it has been found that the selenium concentration can be stably reduced to, for example, 0.2 mg-Se / L or less as the total selenium even under the condition that the oxidation-reduction potential in the anaerobic reaction tank 10 is 0 mV or more. It was. Although the mechanism is not clear, anaerobic parts are locally present inside the biofilm developed on the surface of the porous carrier, and a selenium reduction reaction occurs in the biofilm. It is thought that the contact efficiency with water is enhanced and supports an efficient selenium reduction reaction.
本実施形態に係るセレン含有水の処理方法は、セレン含有水を多孔質の担体に付着した生物汚泥と嫌気状態で接触させることにより、セレン含有水中の溶解性セレンを還元して無害化する。このときＳｅ6+はＳｅ4+を経てＳｅ0およびＳｅ2-のうち少なくとも１つに還元されるものと推定される。本実施形態において、「嫌気状態」とは酸素をばっ気等の手段によって供給することのない状態を意味し、セレン化合物の還元を阻害しない程度の若干の酸素の混入は許容される。 In the method for treating selenium-containing water according to this embodiment, the selenium-containing water is brought into contact with biological sludge attached to a porous carrier in an anaerobic state, thereby reducing and detoxifying soluble selenium in the selenium-containing water. At this time, Se 6+ is estimated to be reduced to at least one of Se 0 and Se 2− via Se 4+ . In the present embodiment, the “anaerobic state” means a state where oxygen is not supplied by means such as aeration, and a slight amount of oxygen that does not inhibit the reduction of the selenium compound is allowed.
上記の反応では嫌気状態であるため、生物汚泥が分子状酸素ではなくセレン酸イオンまたは亜セレン酸イオンの形で含まれる結合酸素を用いて電子受容体とし、セレン酸イオンまたは亜セレン酸イオンが還元される。基質としては有機物が用いられ、セレン含有水に含まれていればそのまま利用できるが、含まれていなければ、例えばメタノール等の有機物が別途添加されてもよい。有機物の添加量が増すと嫌気度が増し、酸化還元電位が下がるが、酸化還元電位測定装置１２を用いて嫌気性反応槽１０内の酸化還元電位が０ｍＶを下回らないよう、有機物の添加量を制御してもよい。 Since the above reaction is anaerobic, biological sludge is converted into an electron acceptor using bound oxygen contained in the form of selenate ion or selenite ion instead of molecular oxygen, and selenate ion or selenite ion is Reduced. As the substrate, an organic substance is used and can be used as it is if it is contained in selenium-containing water. However, if it is not contained, an organic substance such as methanol may be added separately. As the amount of organic matter added increases, the anaerobic degree increases and the redox potential decreases. However, the amount of organic matter added is adjusted so that the redox potential in the anaerobic reaction vessel 10 does not fall below 0 mV using the redox potential measuring device 12. You may control.
このような方法により、メタノール等の有機物の添加量を削減できるとともに、嫌気性反応槽１０内の滞留時間も減らすことができ、より高速での処理が可能となる。 By such a method, the addition amount of organic substances such as methanol can be reduced, and the residence time in the anaerobic reaction tank 10 can also be reduced, so that processing at a higher speed becomes possible.
セレン含有水から生物処理によって溶解性セレンを除去する場合に、嫌気性反応槽１０内の酸化還元電位を下げるために有機物の添加量やセレン含有水の滞留時間が過大になること、また、酸化還元電位が下がりすぎることで硫酸還元が生じることを防ぎつつ、溶解性セレンを不溶化して除去できるようになる。したがって、有機物の添加量を過剰に要したり、生物処理反応槽を大型にする必要が生じたりすることを防止しつつ、溶解性セレンを効率的に不溶化して除去することができる。 When soluble selenium is removed from selenium-containing water by biological treatment, the amount of organic matter added and the residence time of selenium-containing water become excessive in order to lower the oxidation-reduction potential in the anaerobic reaction tank 10, and oxidation Soluble selenium can be insolubilized and removed while preventing the reduction of sulfuric acid due to the reduction potential being too low. Therefore, soluble selenium can be efficiently insolubilized and removed while preventing an excessive amount of organic matter from being added or the necessity of increasing the size of the biological treatment reaction tank.
本実施形態では、有機物の添加量およびセレン含有水の滞留時間のうち少なくとも１つを制御することにより、酸化還元電位が好ましくは−４０ｍＶ以上１７５ｍＶ以下となる条件で、多孔質の担体に保持された生物汚泥とセレン含有水を接触させ、有機物存在下で溶解性セレンを還元することが好ましい。酸化還元電位が−４０ｍＶ未満であると、有機物の添加量が過剰およびセレン含有水の滞留時間が過剰となり、処理水ＣＯＤの上昇や硫化水素の発生等の場合があり、１７５ｍＶを超えると、セレン還元が起きない等の場合がある。 In this embodiment, by controlling at least one of the addition amount of the organic substance and the residence time of the selenium-containing water, the oxidation-reduction potential is preferably held on the porous carrier under the condition that it is −40 mV or more and 175 mV or less. It is preferable to bring the biological sludge into contact with selenium-containing water to reduce soluble selenium in the presence of organic matter. When the oxidation-reduction potential is less than −40 mV, the amount of organic matter added is excessive and the residence time of selenium-containing water is excessive, and there are cases where the treated water COD rises and hydrogen sulfide is generated, and when it exceeds 175 mV, There may be cases where no reduction occurs.
処理対象となるセレン含有水は、セレン酸イオン（ＳｅＯ4 2-：６価セレン）および亜セレン酸イオン（ＳｅＯ3 2-：４価セレン）のうち少なくとも１つ（溶解性セレン）を含む排水またはその他の水である。セレン含有水は、溶解性セレンの他に、セレン単体を含んでいてもよい。 The selenium-containing water to be treated contains wastewater containing at least one (soluble selenium) of selenate ions (SeO 4 2− : hexavalent selenium) and selenite ions (SeO 3 2− : tetravalent selenium). Or other water. The selenium-containing water may contain selenium alone in addition to soluble selenium.
セレン含有水中のセレン酸イオンの濃度は、例えば、０．１〜１０ｍｇ−Ｓｅ／Ｌの範囲であり、亜セレン酸イオンの濃度は、例えば、０．１〜１０ｍｇ−Ｓｅ／Ｌの範囲であるが、これらの範囲に限定されるものではない。特に、溶解性セレンを全セレンとして例えば０．１〜２．０ｍｇ−Ｓｅ／Ｌの範囲、好ましくは０．１〜１．０ｍｇ−Ｓｅ／Ｌの範囲の濃度で含むセレン含有水を処理する場合に好適に適用される。 The concentration of selenate ions in the selenium-containing water is, for example, in the range of 0.1 to 10 mg-Se / L, and the concentration of selenite ions is, for example, in the range of 0.1 to 10 mg-Se / L. However, it is not limited to these ranges. In particular, when treating selenium-containing water containing soluble selenium as total selenium, for example, in a range of 0.1 to 2.0 mg-Se / L, preferably 0.1 to 1.0 mg-Se / L It is preferably applied to.
処理対象となるセレン含有水としては、例えば、金属精錬工業排水、ガラス工業排水、火力発電所排水、鉱山排水、化学工業排水、および石炭、石油または燃焼排ガス処理プロセスの排水等が挙げられる。本実施形態に係るセレン含有水処理方法および処理装置は、特に、石炭火力発電所脱硫排水に好適に適用される。これらのセレン含有水中にはセレン化合物以外に有機物、窒素化合物、硫酸塩等が含まれていてもよい。 Examples of the selenium-containing water to be treated include metal smelting industrial wastewater, glass industrial wastewater, thermal power plant wastewater, mine wastewater, chemical industry wastewater, and wastewater from coal, petroleum or combustion exhaust gas treatment processes. The selenium-containing water treatment method and treatment apparatus according to the present embodiment are particularly suitably applied to coal-fired power plant desulfurization effluent. These selenium-containing waters may contain organic substances, nitrogen compounds, sulfates and the like in addition to selenium compounds.
有機物としては、メタノールの他に、例えば、エタノール、酢酸、ギ酸等が挙げられ、臭気や取扱い、価格等の点から、メタノールが好ましい。 In addition to methanol, examples of the organic substance include ethanol, acetic acid, formic acid, and the like, and methanol is preferable from the viewpoint of odor, handling, price, and the like.
嫌気性反応槽１０における滞留時間は、１２時間未満であるが、１時間〜６時間の範囲が好ましい。嫌気性反応槽１０における滞留時間が１時間未満であると、還元反応が進まない場合があり、１２時間を超えると、過剰となる。嫌気性反応槽１０における滞留時間の制御は、例えば、嫌気性反応槽１０の内容積、嫌気性反応槽１０への原水の供給量等の調整等によって行われ、この場合、原水の供給量の制御装置等が制御手段として機能する。 Although the residence time in the anaerobic reaction tank 10 is less than 12 hours, the range of 1 hour to 6 hours is preferable. If the residence time in the anaerobic reaction tank 10 is less than 1 hour, the reduction reaction may not proceed, and if it exceeds 12 hours, it becomes excessive. The control of the residence time in the anaerobic reaction tank 10 is performed, for example, by adjusting the internal volume of the anaerobic reaction tank 10, the supply amount of raw water to the anaerobic reaction tank 10, and the like. A control device or the like functions as control means.
多孔質の担体としては、ポリビニルアルコール等の親水性ゲルの担体、ポリウレタンスポンジ、ポリオレフィン系樹脂発泡体等が挙げられ、沈降、流動性等の点から親水性ゲルの担体が好ましい。 Examples of the porous carrier include hydrophilic gel carriers such as polyvinyl alcohol, polyurethane sponges, polyolefin resin foams, and the like, and hydrophilic gel carriers are preferred from the viewpoint of sedimentation and fluidity.
多孔質の担体の粒径は、３ｍｍ以上５ｍｍ以下の範囲であることが好ましい。多孔質の担体の粒径が３ｍｍ未満であると、スクリーン等の流出対策措置を通過して担体が流出してしまう場合があり、５ｍｍを超えると、比表面積が低下して微生物保持量が減るとともに流動性も低下し、処理能力が低下する場合がある。 The particle size of the porous carrier is preferably in the range of 3 mm to 5 mm. If the particle size of the porous carrier is less than 3 mm, the carrier may flow out through an anti-spill measure such as a screen. If the particle size exceeds 5 mm, the specific surface area decreases and the amount of microorganisms retained decreases. At the same time, the fluidity is lowered, and the processing capacity may be lowered.
多孔質の担体の比重は、嫌気性反応槽１０内において良好な流動状態とするために、０．１以上１．２以下の範囲であることが好ましい。多孔質の担体の比重が０．１未満であると、浮上して流動しない場合があり、１．２を超えると、沈降したまま流動しない場合がある。 The specific gravity of the porous carrier is preferably in the range of 0.1 or more and 1.2 or less in order to obtain a good fluid state in the anaerobic reaction tank 10. If the specific gravity of the porous carrier is less than 0.1, it may float and do not flow, and if it exceeds 1.2, it may not flow while settling.
本実施形態において、嫌気性反応槽１０の後段に、添加した有機物を除去する目的で酸化槽を設けてもよい。本実施形態に係るセレン含有水処理装置の他の例の概略を図２に示す。図２に示すセレン含有水処理装置３は、図１の構成に加えて、嫌気性反応槽１０の後段に、酸化槽２８を備える。セレン含有水処理装置３において、酸化槽２８には、送気装置３０が設置されている。嫌気性反応槽１０の出口と酸化槽２８の入口は生物処理水配管２４により接続され、酸化槽２８には酸化処理水配管３２が接続されている。 In this embodiment, you may provide an oxidation tank in the back | latter stage of the anaerobic reaction tank 10 in order to remove the added organic substance. FIG. 2 shows an outline of another example of the selenium-containing water treatment apparatus according to this embodiment. The selenium-containing water treatment device 3 shown in FIG. 2 includes an oxidation tank 28 at the rear stage of the anaerobic reaction tank 10 in addition to the configuration of FIG. In the selenium-containing water treatment device 3, an air supply device 30 is installed in the oxidation tank 28. The outlet of the anaerobic reaction tank 10 and the inlet of the oxidation tank 28 are connected by a biological treatment water pipe 24, and the oxidation treatment water pipe 32 is connected to the oxidation tank 28.
原水であるセレン含有水は、図１のセレン含有水処理装置１と同様にして嫌気性反応槽１０において生物処理が行われた（生物処理工程）後、嫌気性反応槽１０から生物処理水配管２４を通して酸化槽２８に送液される。酸化槽２８において、送気装置３０から空気等の酸素含有気体が吹き込まれ、酸化的条件下で余剰の有機物が除去される（酸化工程）。酸化槽２８内の生物は担体を用いて担持させてもよいし、浮遊式の活性汚泥でもよい。酸化処理された酸化処理水は、酸化処理水配管３２を通して処理水として排出される。 Selenium-containing water that is raw water is subjected to biological treatment in the anaerobic reaction tank 10 in the same manner as the selenium-containing water treatment apparatus 1 in FIG. 1 (biological treatment step), and then the biologically treated water pipe from the anaerobic reaction tank 10. 24 is fed to the oxidation tank 28. In the oxidation tank 28, oxygen-containing gas such as air is blown from the air supply device 30, and excess organic substances are removed under oxidative conditions (oxidation process). The organism in the oxidation tank 28 may be supported using a carrier, or may be floating activated sludge. The oxidized treated water subjected to oxidation treatment is discharged as treated water through the oxidized treated water pipe 32.
本実施形態において、セレン含有水が溶解性セレンとともに硝酸および亜硝酸のうち少なくとも１つを含む場合は、嫌気性反応槽１０の前段に脱窒槽を設けてもよい。図３に示すセレン含有水処理装置５は、図２の構成に加えて、嫌気性反応槽１０の前段に、脱窒槽３４を備える。脱窒槽３４には、撹拌羽根等を有する撹拌装置３６が設置されている。セレン含有水処理装置５において、脱窒槽３４の入口には原水配管３８が接続され、脱窒槽３４の出口と嫌気性反応槽１０の入口は脱窒処理水配管４０により接続されている。 In the present embodiment, when the selenium-containing water contains at least one of nitric acid and nitrous acid together with soluble selenium, a denitrification tank may be provided in front of the anaerobic reaction tank 10. The selenium-containing water treatment apparatus 5 shown in FIG. 3 includes a denitrification tank 34 in the front stage of the anaerobic reaction tank 10 in addition to the configuration of FIG. The denitrification tank 34 is provided with a stirring device 36 having stirring blades and the like. In the selenium-containing water treatment apparatus 5, a raw water pipe 38 is connected to the inlet of the denitrification tank 34, and the outlet of the denitrification tank 34 and the inlet of the anaerobic reaction tank 10 are connected by a denitrification treatment water pipe 40.
原水であるセレン含有水は、必要に応じて原水槽へ貯留された後、原水配管３８を通して、嫌気性反応槽１０と同様に多孔質の担体が充填された流動床式等の脱窒槽３４へ供給される。脱窒槽３４において、多孔質の担体に脱窒菌を担持させてメタノール等の有機物を添加して脱窒反応させればよい（脱窒工程）。脱窒処理された脱窒処理水は、脱窒処理水配管４０を通して嫌気性反応槽１０へ送液され、図２のセレン含有水処理装置３と同様にして、嫌気性反応槽１０において生物処理が行われた（生物処理工程）後、酸化槽２８において、酸化的条件下で余剰の有機物が除去される（酸化工程）。 Selenium-containing water, which is raw water, is stored in the raw water tank as necessary, and then passed through the raw water pipe 38 to a denitrification tank 34 such as a fluidized bed type filled with a porous carrier in the same manner as the anaerobic reaction tank 10. Supplied. In the denitrification tank 34, denitrifying bacteria may be supported on a porous carrier and an organic substance such as methanol may be added to cause a denitrification reaction (denitrification step). The denitrified water subjected to the denitrification process is sent to the anaerobic reaction tank 10 through the denitrification process water pipe 40, and the biological treatment is performed in the anaerobic reaction tank 10 in the same manner as the selenium-containing water treatment apparatus 3 in FIG. Is carried out (biological treatment process), excess organic substances are removed under oxidizing conditions in the oxidation tank 28 (oxidation process).
本実施形態において、セレン含有水がさらにアンモニアを含む場合には、脱窒槽３４の前段に硝化槽を設けてもよい。図４に示すセレン含有水処理装置７は、図３の構成に加えて、脱窒槽３４の前段に、硝化槽４２を備える。硝化槽４２には、送気装置４４が設置されている。セレン含有水処理装置７において、硝化槽４２の入口には原水配管４６が接続され、硝化槽４２の出口と脱窒槽３４の入口は硝化処理水配管４８により接続されている。 In the present embodiment, when the selenium-containing water further contains ammonia, a nitrification tank may be provided in front of the denitrification tank 34. The selenium-containing water treatment device 7 shown in FIG. 4 includes a nitrification tank 42 in the previous stage of the denitrification tank 34 in addition to the configuration of FIG. An air supply device 44 is installed in the nitrification tank 42. In the selenium-containing water treatment device 7, a raw water pipe 46 is connected to the inlet of the nitrification tank 42, and the outlet of the nitrification tank 42 and the inlet of the denitrification tank 34 are connected by a nitrification water pipe 48.
原水であるセレン含有水は、必要に応じて原水槽へ貯留された後、原水配管４６を通して硝化槽４２へ送液され、硝化槽４２においてアンモニアが反応し、硝酸が生成する（硝化工程）。硝化処理された硝化処理水は、硝化処理水配管４８を通して脱窒槽３４へ送液され、図３のセレン含有水処理装置５と同様にして、脱窒槽３４において脱窒処理され（脱窒工程）、嫌気性反応槽１０において生物処理が行われた（生物処理工程）後、酸化槽２８において、酸化的条件下で余剰の有機物が除去される（酸化工程）。 Selenium-containing water, which is raw water, is stored in the raw water tank as necessary, and then sent to the nitrification tank 42 through the raw water pipe 46, where ammonia reacts in the nitrification tank 42 to generate nitric acid (nitrification step). The nitrified water subjected to nitrification is fed to the denitrification tank 34 through the nitrification water pipe 48 and is denitrified in the denitrification tank 34 in the same manner as the selenium-containing water treatment apparatus 5 in FIG. 3 (denitrification step). After the biological treatment is performed in the anaerobic reaction tank 10 (biological treatment process), excess organic substances are removed in the oxidation tank 28 under oxidative conditions (oxidation process).
以下、実施例および比較例を挙げ、本発明をより具体的に詳細に説明するが、本発明は、以下の実施例に限定されるものではない。 Hereinafter, although an example and a comparative example are given and the present invention is explained more concretely in detail, the present invention is not limited to the following examples.
＜実施例１＞
図１に示すセレン含有水処理装置１を用い、６価のセレン酸イオンを約１．０ｍｇ／Ｌ、硝酸態窒素を３７〜５６ｍｇ−Ｎ／Ｌ含む模擬排煙脱硫排水を嫌気性処理によりセレンの還元を行った。有機物源としてメタノールを添加した。硝酸態窒素に対するメタノールの添加比率は２．５ｇ／ｇＮ以下であり、嫌気性反応槽における滞留時間を１〜１．１時間に制御した。嫌気性反応槽では無機アンモニア処理装置の活性汚泥を種汚泥として、多孔質の担体として親水性ゲル担体（材質：ポリビニルアルコール、粒径４ｍｍ）を水槽容積比で２０％充填して嫌気性処理を行った。結果を図５に示す。図５に示すように、嫌気性処理槽の酸化還元電位（ＯＲＰ）は−２２〜＋１７５ｍＶであり、処理水中のセレン濃度はＩＣＰ−ＭＳにて測定し、全セレンとして０．２ｍｇ−Ｓｅ／Ｌ以下の範囲で安定して処理することができた。
<Example 1>
Using the selenium-containing water treatment apparatus 1 shown in FIG. 1, a simulated flue gas desulfurization waste water containing about 1.0 mg / L of hexavalent selenate ions and 37 to 56 mg-N / L of nitrate nitrogen is subjected to anaerobic treatment. Reduced. Methanol was added as an organic source. The addition ratio of methanol to nitrate nitrogen was 2.5 g / gN or less, and the residence time in the anaerobic reaction tank was controlled to 1 to 1.1 hours. In the anaerobic reaction tank, the activated sludge of the inorganic ammonia treatment apparatus is used as seed sludge, and a hydrophilic gel carrier (material: polyvinyl alcohol, particle size 4 mm) is filled as a porous carrier by 20% in the water tank volume ratio for anaerobic treatment. went. The results are shown in FIG. As shown in FIG. 5, the redox potential (ORP) of the anaerobic treatment tank is −22 to +175 mV, and the selenium concentration in the treated water is measured by ICP-MS, and 0.2 mg-Se / L as total selenium. The treatment was stable within the following range.
＜比較例１＞
実施例１と同様の条件で嫌気性反応槽への通水流量を減らして滞留時間を１２時間超である３０時間として嫌気性処理を行った。このとき、硝酸態窒素に対するメタノールの添加比率は３．０ｇ／ｇＮ以上であり、脱窒反応等量として過剰であった。結果を図６に示す。図６に示すように、嫌気性処理槽の酸化還元電位は−６０〜−２０２ｍＶであり、処理水中のセレン濃度は全セレンとして０．２ｍｇ−Ｓｅ／Ｌ以下の範囲で安定して処理することができたが、処理性能は実施例１と比べて大きな差異はなかった。
<Comparative Example 1>
The anaerobic treatment was performed under the same conditions as in Example 1 by reducing the flow rate of water to the anaerobic reaction tank and setting the residence time to 30 hours, which was more than 12 hours. At this time, the addition ratio of methanol to nitrate nitrogen was 3.0 g / gN or more, which was excessive as an equivalent amount of denitrification reaction. The results are shown in FIG. As shown in FIG. 6, the redox potential of the anaerobic treatment tank is −60 to −202 mV, and the selenium concentration in the treated water is stably treated in the range of 0.2 mg-Se / L or less as the total selenium. However, the processing performance was not significantly different from that of Example 1.
＜比較例２＞
図７に示すセレン含有水処理装置９を用い、実施例１と同様の条件で親水性ゲル担体を用いずに、浮遊式活性汚泥の条件で嫌気性処理を行った。図７のセレン含有水処理装置９において、生物処理水配管２４が沈殿槽５０の入口に接続され、沈殿処理水配管５２が沈殿槽５０の上部の処理水出口に接続され、沈殿槽５０の下部の汚泥出口と嫌気性反応槽１０とが汚泥返送配管５４によりポンプ５６を介して接続されている。滞留時間は１２時間であった。電力排煙脱硫排水処理装置の活性汚泥を種汚泥とし、ＭＬＳＳ ４０００ｍｇ／Ｌで処理を行った。結果は図８に示すように処理槽内のＯＲＰは−２００〜＋４０ｍＶであり、処理水中のセレン濃度は全セレンとして０．２〜１．０ｍｇ／Ｌの範囲で不安定であった。
<Comparative example 2>
Using the selenium-containing water treatment device 9 shown in FIG. 7, anaerobic treatment was performed under the conditions of floating activated sludge under the same conditions as in Example 1 without using a hydrophilic gel carrier. In the selenium-containing water treatment apparatus 9 of FIG. 7, the biological treatment water pipe 24 is connected to the inlet of the precipitation tank 50, the precipitation treatment water pipe 52 is connected to the treatment water outlet at the upper part of the precipitation tank 50, and the lower part of the precipitation tank 50. The sludge outlet and the anaerobic reaction tank 10 are connected by a sludge return pipe 54 via a pump 56. The residence time was 12 hours. The activated sludge of the power flue gas desulfurization waste water treatment apparatus was used as seed sludge and treated with MLSS 4000 mg / L. As a result, as shown in FIG. 8, the ORP in the treatment tank was −200 to +40 mV, and the selenium concentration in the treated water was unstable in the range of 0.2 to 1.0 mg / L as the total selenium.
このように、実施例１では、生物学的処理方法を利用するセレン含有水の処理において、滞留時間を１２時間未満に制御して、セレン含有水を通性嫌気性条件下および有機物の存在下で多孔質の流動担体に保持された生物汚泥と接触させることにより、溶解性セレンを効率的に除去することができた。 Thus, in Example 1, in the treatment of selenium-containing water using a biological treatment method, the residence time is controlled to be less than 12 hours, so that the selenium-containing water is permeable under anaerobic conditions and in the presence of organic matter. Thus, soluble selenium could be efficiently removed by contacting with biological sludge held on a porous fluid carrier.
１，３，５，７，９ セレン含有水処理装置、１０ 嫌気性反応槽、１２ 酸化還元電位測定装置、１４，３６ 撹拌装置、１６ 有機物供給槽、１８，５６ ポンプ、２０ 有機物供給量制御装置、２２，３８，４６ 原水配管、２４ 生物処理水配管、２６ 有機物配管、２８ 酸化槽、３０，４４ 送気装置、３２ 酸化処理水配管、３４ 脱窒槽、４０ 脱窒処理水配管、４２ 硝化槽、４８ 硝化処理水配管、５０ 沈殿槽、５２ 沈殿処理水配管、５４ 汚泥返送配管。 1,3,5,7,9 Selenium-containing water treatment apparatus, 10 anaerobic reaction tank, 12 oxidation-reduction potential measurement apparatus, 14,36 stirring apparatus, 16 organic substance supply tank, 18,56 pump, 20 organic substance supply amount control apparatus , 22, 38, 46 Raw water piping, 24 Biologically treated water piping, 26 Organic matter piping, 28 Oxidation tank, 30, 44 Air supply device, 32 Oxidized water piping, 34 Denitrification tank, 40 Denitrification treated water piping, 42 Nitrification tank , 48 Nitrification water piping, 50 sedimentation tank, 52 sedimentation water piping, 54 sludge return piping.
Claims (8)
前記流動担体は、粒径３ｍｍ以上５ｍｍ以下、比重０．１以上１．２以下の親水性のポリビニルアルコール担体であることを特徴とするセレン含有水の処理方法。 By controlling the residence time to less than 12 hours, it viewed including the biological treatment step of contacting the selenium-containing water in the presence of facultative anaerobic conditions and the organic porous biological sludge held in the flow carrier,
The method for treating selenium-containing water, wherein the fluid carrier is a hydrophilic polyvinyl alcohol carrier having a particle size of 3 mm to 5 mm and a specific gravity of 0.1 to 1.2 .
前記セレン含有水の全セレン濃度が、０．１〜２．０ｍｇ−Ｓｅ／Ｌの範囲であることを特徴とするセレン含有水の処理方法。 The method for treating selenium-containing water according to claim 1,
The total selenium concentration of the selenium-containing water is in the range of 0.1 to 2.0 mg-Se / L.
前記セレン含有水が、石炭火力発電所脱硫排水であることを特徴とするセレン含有水の処理方法。 A method for treating selenium-containing water according to claim 1 or 2,
The method for treating selenium-containing water, wherein the selenium-containing water is a coal-fired power plant desulfurization effluent.
前記生物処理工程において、酸化還元電位が−４０ｍＶ以上１７５ｍＶ以下となる条件で前記セレン含有水を前記生物汚泥と接触させることを特徴とするセレン含有水の処理方法。 In the biological treatment step, the selenium-containing water treatment method is characterized in that the selenium-containing water is brought into contact with the biological sludge under a condition that an oxidation-reduction potential is -40 mV or more and 175 mV or less.
前記流動担体は、粒径３ｍｍ以上５ｍｍ以下、比重０．１以上１．２以下の親水性のポリビニルアルコール担体であることを特徴とするセレン含有水の処理装置。 Comprising a biological treatment means for controlling the residence time to be less than 12 hours and bringing the selenium-containing water into contact with the biological sludge retained on the porous fluid carrier under the permeabilized anaerobic condition and in the presence of organic matter ,
Wherein the flow carrier, the particle size 3mm or 5mm or less, the processing apparatus of selenium-containing water, wherein the polyvinyl alcohol carrier der Rukoto specific gravity 0.1 to 1.2 hydrophilic.
前記セレン含有水の全セレン濃度が、０．１〜２．０ｍｇ−Ｓｅ／Ｌの範囲であることを特徴とするセレン含有水の処理装置。 The selenium-containing water treatment apparatus according to claim 5 ,
The total selenium concentration of the selenium-containing water is in the range of 0.1 to 2.0 mg-Se / L.
前記セレン含有水が、石炭火力発電所脱硫排水であることを特徴とするセレン含有水の処理装置。 The selenium-containing water treatment apparatus according to claim 5 or 6 ,
The apparatus for treating selenium-containing water, wherein the selenium-containing water is a coal-fired power plant desulfurization effluent.
前記生物処理手段において、酸化還元電位が−４０ｍＶ以上１７５ｍＶ以下となる条件で前記セレン含有水を前記生物汚泥と接触させることを特徴とするセレン含有水の処理装置。 In the biological treatment means, the selenium-containing water treatment apparatus, wherein the selenium-containing water is brought into contact with the biological sludge under a condition that an oxidation-reduction potential is -40 mV or more and 175 mV or less.
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