WO2023026661A1 - Method for treating fluorine-containing water - Google Patents

Method for treating fluorine-containing water Download PDF

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WO2023026661A1
WO2023026661A1 PCT/JP2022/025086 JP2022025086W WO2023026661A1 WO 2023026661 A1 WO2023026661 A1 WO 2023026661A1 JP 2022025086 W JP2022025086 W JP 2022025086W WO 2023026661 A1 WO2023026661 A1 WO 2023026661A1
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tank
calcium
fluorine
reaction
sludge
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浩一 永田
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栗田工業株式会社
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    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C02F1/54—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using organic material
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/58—Treatment of water, waste water, or sewage by removing specified dissolved compounds

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  • the present invention relates to a fluorine-containing water treatment method for removing fluorine from fluorine-containing water.
  • a calcium compound such as slaked lime and calcium chloride is added to the fluorine-containing water in a reaction tank to adjust the pH to 6 to 10 to precipitate a precipitate containing calcium fluoride, and a coagulation tank.
  • a polymer flocculant is added to cause flocculation reaction, and sedimentation is carried out in a sedimentation tank.
  • the flocs generated are gel-like hydroxides that contain a large amount of water, so they have poor sedimentation properties. Moreover, the resulting sludge has poor dewatering properties and is not easy to treat. Also, the fluorine concentration in the treated water could not be sufficiently lowered.
  • Patent Document 1 discloses a reaction tank for reacting fluorine-containing water and a calcium compound, a raw water channel for introducing fluorine-containing water into the reaction tank, and transferring the reaction solution from the reaction tank. Then, using a flocculation device for flocculation by adding a polymer flocculant and a solid-liquid separation tank for performing solid-liquid separation by introducing a mixed liquid containing flocs formed in the flocculation device, separation in the solid-liquid separation tank describes a fluorine removing method in which a part of the sludge obtained is introduced into a reforming tank, a calcium compound is added thereto, and then circulated to a reaction tank.
  • JP-A-10-479 JP 2007-190517 A Japanese Patent Application Laid-Open No. 2009-233568
  • the amount of calcium compound added to the sludge reforming tank is controlled based on the results of measuring the raw water flow rate and fluorine concentration.
  • the concentration of the calcium compound aqueous solution may not be the set value, and the amount of calcium compound to be added may deviate from the target value. be.
  • the present invention is a fluorine-containing water treatment method in which a part of sludge separated in a solid-liquid separation tank is introduced into a sludge reforming tank, a calcium compound is added, and then circulated to a reaction tank.
  • An object of the present invention is to provide a fluorine-containing water treatment method capable of controlling the amount of a calcium compound to be added so as to be an appropriate amount.
  • the fluorine-containing water treatment method of the present invention comprises a reaction tank in which raw water made of fluorine-containing water and a calcium compound are reacted to generate a reaction liquid, a raw water channel for introducing the raw water into the reaction tank, and a reaction liquid from the reaction tank.
  • a flocculation device that transfers and adds a polymer flocculant to flocculate, a solid-liquid separation tank that introduces a mixed liquid containing flocs formed in the flocculation device and performs solid-liquid separation, and a solid-liquid separation tank.
  • a portion of the sludge obtained is introduced into a sludge reforming tank, a calcium compound is added by a calcium compound addition means, and a circulation path for circulating it to the reaction tank is used to treat fluorine-containing water.
  • the method is characterized in that the addition amount of the calcium compound to the sludge reforming tank is controlled based on the raw water fluorine concentration and raw water flow rate, and the calcium concentration in the reaction liquid.
  • a first reaction tank into which raw water and sludge from the sludge reforming tank are introduced, and an effluent from the first reaction tank is introduced, and a pH adjuster is added.
  • a second reaction tank is provided, and the sludge reforming tank is based on the fluorine concentration and raw water flow rate of the raw water, and the calcium concentration in the reaction liquid in the second reaction tank or outflowing from the second reaction tank. Control the amount of calcium compound added to the
  • a reference addition amount is determined so as to be equivalent to the fluorine introduction amount to the first reaction tank, and this reference addition amount is discharged into or out of the second reaction tank. Correct based on the detected calcium concentration in the reaction solution.
  • the addition amount of the calcium compound is determined according to the difference between the calcium concentration target value and the detected calcium concentration. is increased, and when the detected calcium concentration in the reaction solution is higher than a preset calcium concentration target value, the addition amount of the calcium compound is decreased according to the difference between the detected calcium concentration and the calcium concentration target value.
  • calcium hydroxide slurry is added as the calcium compound.
  • the amount of calcium compound added to the sludge reforming tank is controlled based on not only the fluorine concentration in the raw water but also the calcium concentration in the reaction liquid. can be properly controlled. This also improves the quality of the treated water. In addition, since the calcium concentration in the treated water is low and calcium scale is suppressed, it becomes possible to apply biological treatment after this treatment.
  • FIG. 1 is a configuration diagram of a fluorine-containing water treatment apparatus according to an embodiment
  • FIG. 1 is a system diagram showing an embodiment of a fluorine-containing water treatment apparatus for carrying out the method of the present invention.
  • FIG. 2 indicates a second reaction tank, 3 a coagulation tank, 4 a sedimentation tank, and 5 a sludge reforming tank.
  • the raw water pipe 1a is provided with a raw water flow meter 21 and a fluorine sensor 16 including a fluorine ion electrode or the like for detecting the fluorine concentration of the raw water.
  • the reaction between the raw water and the calcium compound is carried out in the first reaction tank 1 and the second reaction tank 2 arranged in series in two stages. That is, the modified sludge from the sludge reforming tank 5 is added to the first reaction tank 1, and a calcium compound and a pH adjuster are added as necessary, preferably pH 4 to 10, more preferably pH 6 to 6. At 5, most of the fluorine in the raw water is insolubilized.
  • the effluent of the first reaction tank 1 is introduced into the second reaction tank 2, and if necessary, a pH adjuster is added to remove residual fluorine at a pH of preferably 4 to 10, more preferably pH 6 to 6.5. Insolubilize.
  • a calcium compound may be added in addition to the pH adjuster.
  • a calcium sensor 9 such as a calcium ion sensor for detecting the calcium ion concentration is provided in the second reaction tank 2 .
  • the calcium sensor 9 may be installed in the pipe 2a between the second reaction tank 2 and the flocculation tank 3, or in the pipe 4a after the treated water of the sedimentation tank 4.
  • the effluent from the second reaction tank 2 is introduced into the flocculation tank 3, added with a polymer flocculant, and flocculated.
  • the polymer flocculant is not particularly limited as long as it is used for the flocculation treatment of suspended waste water, and for example, a polyacrylamide-based polymer flocculant is used.
  • a polymer flocculant after adding an inorganic flocculant such as PAC or aluminum sulfate.
  • the flocculation treated water in the flocculation tank 3 is then introduced into the sedimentation tank 4 through the pipe 3a, solid-liquid separated, and the separated water is discharged out of the system as treated water.
  • Part of the separated sludge is sent to the sludge reforming tank 5 as returned sludge, and the rest is discharged out of the system as excess sludge.
  • the sludge reforming tank 5 By adding and mixing the calcium compound in the sludge reforming tank 5, at least part of the calcium compound adheres to the surface of the sludge by adsorption or the like, and the sludge is reformed.
  • this modified sludge is introduced into the first reaction tank 1, calcium compounds on the surface of the sludge react with fluorine in the raw water to grow sludge particles.
  • the sludge that has undergone grain growth in this way has good sedimentation properties, and is efficiently sedimented in the sedimentation tank 4 .
  • a calcium compound is added to the sludge reforming tank 5 in the form of a calcium compound-containing liquid (eg, water slurry of slaked lime (calcium hydroxide) or calcium carbonate, calcium chloride aqueous solution).
  • the calcium compound-containing liquid is preferably slaked lime slurry, and its concentration is 20 wt % or less, desirably 10 wt %.
  • a calcium chloride aqueous solution is used at a standard concentration (for example, 35 wt %).
  • the calcium compound-containing liquid is added to the sludge reforming tank 5 via a pipe 10, an on-off valve 11, a pipe 12, a control valve 13, and a pipe 14 by means of a pump or the like.
  • the control valve 13 is configured so that the degree of opening (that is, the amount of calcium compound supplied) can be changed continuously, and the degree of opening is controlled by the controller 15 .
  • a controller 15 receives detection signals from a calcium sensor 9, a fluorine sensor 16 including a fluoride ion electrode or the like for detecting the fluorine concentration of raw water, a detection signal from a raw water flow meter 21 in the raw water pipe, and The opening of the control valve 13 is controlled based on the detection signal of the flow meter 17 .
  • the amount of the calcium compound to be added is basically determined so as to be equivalent to the amount of fluorine introduced into the first reaction tank 1 (obtained from the product of the flow rate of the raw water and the fluorine concentration of the raw water).
  • this reference addition amount is determined by correcting it based on the calcium concentration detected by the calcium sensor 9 .
  • this correction when the calcium concentration detected by the calcium sensor 9 is lower than a preset calcium concentration target value, the addition amount of the calcium compound is increased according to the difference between the calcium concentration target value and the detected calcium concentration. Conversely, when the calcium concentration detected by the calcium sensor 9 is higher than the preset calcium concentration target value, the addition amount of the calcium compound is reduced according to the difference between the detected calcium concentration and the calcium concentration target value.
  • washing water can be supplied to the pipe 12 through a pipe 19 having a valve 18 in order to prevent the control valve 13 from being blocked.
  • a pipe 19 having a valve 18 By closing the valve 11 and opening the valve 18, washing water is passed through the control valve 13, and the control valve 13 is washed with this washing water to prevent clogging.
  • the cleaning of the control valve 13 with the cleaning water is preferably performed periodically by a timer, for example, once every 5 minutes to 24 hours, particularly once every hour.
  • the water flow time is 1 to 10 minutes, particularly about 2 minutes and 30 seconds, but is not limited to this. Tap water, industrial water, or the like can be used as the washing water.
  • the amount of calcium compound added is corrected by the detection value of the calcium sensor 9, so even if the calcium compound concentration of the calcium compound solution fluctuates, appropriate calcium compound addition control is performed. Thereby, it becomes possible to obtain treated water of good quality, and for example, the fluorine concentration and calcium concentration in the treated water can be lowered. This also facilitates recycling of the treated water.
  • control valve 13 since the control valve 13 is washed with washing water, the control valve 13 is prevented from being clogged and stable processing is possible.

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  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Removal Of Specific Substances (AREA)
  • Separation Of Suspended Particles By Flocculating Agents (AREA)

Abstract

Provided is a method for treating fluorine-containing water, which can control the amount of a calcium compound added to a sludge modification tank to a proper amount in a fluorine-containing water treatment device in which a part of sludge separated in a solid-liquid separation tank is introduced into a modification tank, and a calcium compound is added thereto, followed by circulation to a reaction tank. In a first reaction tank 1, modified sludge from a sludge modification tank 5 and, if required, a calcium compound and a pH adjuster are added to raw water, and the resultant is introduced into a flocculation tank 3 through a second reaction tank 2 and subjected to flocculation treatment. Flocculation treatment water in the flocculation tank 3 is subjected to solid-liquid separation in a precipitation tank 4, and a part of the separated sludge is introduced into the sludge modification tank 5. A calcium compound-containing liquid is added to the sludge modification tank 5 via a control valve 13. The amount of the calcium compound added is controlled on the basis of the flow rate and fluorine concentration of raw water and the calcium concentration in the second reaction tank 2.

Description

フッ素含有水の処理方法Method for treating fluorine-containing water
　本発明はフッ素含有水からフッ素を除去するためのフッ素含有水の処理方法に関するものである。 The present invention relates to a fluorine-containing water treatment method for removing fluorine from fluorine-containing water.
　フッ素含有水からフッ素を除去する方法として、反応槽においてフッ素含有水に消石灰、塩化カルシウムなどのカルシウム化合物を添加してｐＨ６～１０に調整してフッ化カルシウムを含む析出物を析出させ、凝集槽において高分子凝集剤を添加して凝集反応を行い、沈殿槽で沈殿分離する方法が行われている。 As a method for removing fluorine from fluorine-containing water, a calcium compound such as slaked lime and calcium chloride is added to the fluorine-containing water in a reaction tank to adjust the pH to 6 to 10 to precipitate a precipitate containing calcium fluoride, and a coagulation tank. In the method, a polymer flocculant is added to cause flocculation reaction, and sedimentation is carried out in a sedimentation tank.
　しかしこのような処理方法では、生成するフロックは多量に水を含むゲル状の水酸化物であるため、沈降性が悪い。また、生成する汚泥は脱水性が悪く、その処理は容易ではなかった。また、処理水のフッ素濃度を十分に低くすることはできなかった。 However, with such a treatment method, the flocs generated are gel-like hydroxides that contain a large amount of water, so they have poor sedimentation properties. Moreover, the resulting sludge has poor dewatering properties and is not easy to treat. Also, the fluorine concentration in the treated water could not be sufficiently lowered.
　このような点を改善する方法として、特許文献１には、フッ素含有水とカルシウム化合物を反応させる反応槽と、この反応槽にフッ素含有水を導入する原水路と、反応槽から反応液を移送し高分子凝集剤を添加して凝集を行う凝集装置と、凝集装置において形成されるフロックを含む混合液を導入して固液分離を行う固液分離槽とを用い、固液分離槽で分離された汚泥の一部を改質槽に導入し、カルシウム化合物を添加してから反応槽に循環させるフッ素除去方法が記載されている。 As a method for improving such points, Patent Document 1 discloses a reaction tank for reacting fluorine-containing water and a calcium compound, a raw water channel for introducing fluorine-containing water into the reaction tank, and transferring the reaction solution from the reaction tank. Then, using a flocculation device for flocculation by adding a polymer flocculant and a solid-liquid separation tank for performing solid-liquid separation by introducing a mixed liquid containing flocs formed in the flocculation device, separation in the solid-liquid separation tank describes a fluorine removing method in which a part of the sludge obtained is introduced into a reforming tank, a calcium compound is added thereto, and then circulated to a reaction tank.
　同様のフッ素含有水の処理方法が特許文献２，３にも記載されている。 A similar method for treating fluorine-containing water is also described in Patent Documents 2 and 3.
特開平１０－４７９号公報JP-A-10-479 特開２００７－１９０５１７号公報JP 2007-190517 A 特開２００９－２３３５６８号公報Japanese Patent Application Laid-Open No. 2009-233568
　前記汚泥改質槽に対するカルシウム化合物の添加量は、原水の流量及びフッ素濃度を測定し、その結果に基づいて制御される。 The amount of calcium compound added to the sludge reforming tank is controlled based on the results of measuring the raw water flow rate and fluorine concentration.
　ところが、カルシウム化合物が消石灰（水酸化カルシウム）、炭酸カルシウムなどのように難溶性である場合、カルシウム化合物水溶液の濃度が設定値通りとならず、カルシウム化合物の添加量が目的値から乖離することがある。 However, if the calcium compound is poorly soluble, such as slaked lime (calcium hydroxide) or calcium carbonate, the concentration of the calcium compound aqueous solution may not be the set value, and the amount of calcium compound to be added may deviate from the target value. be.
　汚泥改質槽に対するカルシウム化合物の添加が不足する場合には、フッ素含有水からのフッ素除去が不十分になる。逆にカルシウム化合物の添加が過剰である場合には、薬品コストが嵩むだけでなく、処理水を再利用する場合には、処理水中のカルシウム濃度を低下させるための処理が必要になる。 　If the addition of calcium compounds to the sludge reforming tank is insufficient, the removal of fluorine from the fluorine-containing water will be insufficient. Conversely, if the calcium compound is added excessively, not only does the chemical cost increase, but if the treated water is to be reused, treatment to reduce the calcium concentration in the treated water is required.
　本発明は、固液分離槽で分離された汚泥の一部を汚泥改質槽に導入し、カルシウム化合物を添加してから反応槽に循環させるフッ素含有水の処理方法において、汚泥改質槽に対するカルシウム化合物の添加量が適正量となるように制御することができるフッ素含有水の処理方法を提供することを課題とする。 The present invention is a fluorine-containing water treatment method in which a part of sludge separated in a solid-liquid separation tank is introduced into a sludge reforming tank, a calcium compound is added, and then circulated to a reaction tank. An object of the present invention is to provide a fluorine-containing water treatment method capable of controlling the amount of a calcium compound to be added so as to be an appropriate amount.
　本発明のフッ素含有水の処理方法は、フッ素含有水よりなる原水とカルシウム化合物を反応させて反応液を生成させる反応槽と、この反応槽に原水を導入する原水路と、反応槽から反応液を移送し高分子凝集剤を添加して凝集を行う凝集装置と、凝集装置において形成されるフロックを含む混合液を導入して固液分離を行う固液分離槽と、固液分離槽で分離された汚泥の一部を汚泥改質槽に導入し、カルシウム化合物をカルシウム化合物添加手段により添加して反応槽に循環させる循環路とを有するフッ素含有水の処理装置を用いたフッ素含有水の処理方法において、原水のフッ素濃度及び原水流量と、前記反応液中のカルシウム濃度とに基づいて前記汚泥改質槽へのカルシウム化合物の添加量を制御することを特徴とする。 The fluorine-containing water treatment method of the present invention comprises a reaction tank in which raw water made of fluorine-containing water and a calcium compound are reacted to generate a reaction liquid, a raw water channel for introducing the raw water into the reaction tank, and a reaction liquid from the reaction tank. A flocculation device that transfers and adds a polymer flocculant to flocculate, a solid-liquid separation tank that introduces a mixed liquid containing flocs formed in the flocculation device and performs solid-liquid separation, and a solid-liquid separation tank. A portion of the sludge obtained is introduced into a sludge reforming tank, a calcium compound is added by a calcium compound addition means, and a circulation path for circulating it to the reaction tank is used to treat fluorine-containing water. The method is characterized in that the addition amount of the calcium compound to the sludge reforming tank is controlled based on the raw water fluorine concentration and raw water flow rate, and the calcium concentration in the reaction liquid.
　本発明の一態様では、前記反応槽として、原水及び前記汚泥改質槽からの汚泥が導入される第１反応槽と、該第１反応槽流出液が導入され、ｐＨ調整剤が添加される第２反応槽とが設けられており、原水のフッ素濃度及び原水流量と、該第２反応槽内又は該第２反応槽から流出する反応液中のカルシウム濃度とに基づいて前記汚泥改質槽へのカルシウム化合物添加量を制御する。 In one aspect of the present invention, as the reaction tank, a first reaction tank into which raw water and sludge from the sludge reforming tank are introduced, and an effluent from the first reaction tank is introduced, and a pH adjuster is added. A second reaction tank is provided, and the sludge reforming tank is based on the fluorine concentration and raw water flow rate of the raw water, and the calcium concentration in the reaction liquid in the second reaction tank or outflowing from the second reaction tank. Control the amount of calcium compound added to the
　本発明の一態様では、前記第１反応槽へのフッ素導入量と当量となるように基準添加量を決定し、この基準添加量を該第２反応槽内又は該第２反応槽から流出する反応液中の検出カルシウム濃度に基づいて補正する。 In one aspect of the present invention, a reference addition amount is determined so as to be equivalent to the fluorine introduction amount to the first reaction tank, and this reference addition amount is discharged into or out of the second reaction tank. Correct based on the detected calcium concentration in the reaction solution.
　本発明の一態様では、前記補正として、前記反応液中のカルシウム濃度が予め設定したカルシウム濃度目標値よりも低いときには、カルシウム濃度目標値と検出カルシウム濃度との差に応じてカルシウム化合物の添加量を増加させ、前記反応液中の検出カルシウム濃度が予め設定したカルシウム濃度目標値よりも高いときには、検出カルシウム濃度とカルシウム濃度目標値との差に応じてカルシウム化合物の添加量を減少させる。 In one aspect of the present invention, as the correction, when the calcium concentration in the reaction solution is lower than a preset calcium concentration target value, the addition amount of the calcium compound is determined according to the difference between the calcium concentration target value and the detected calcium concentration. is increased, and when the detected calcium concentration in the reaction solution is higher than a preset calcium concentration target value, the addition amount of the calcium compound is decreased according to the difference between the detected calcium concentration and the calcium concentration target value.
　本発明の一態様では、前記カルシウム化合物として水酸化カルシウムスラリーを添加する。 In one aspect of the present invention, calcium hydroxide slurry is added as the calcium compound.
　本発明のフッ素含有水の処理方法では、汚泥改質槽へのカルシウム化合物の添加量を原水中のフッ素濃度だけでなく反応液中のカルシウム濃度に基づいて制御するので、カルシウム化合物の添加量を適切に制御することができる。これにより、処理水の水質も向上する。また、処理水中のカルシウム濃度が低く、カルシウムスケールが抑制されるため、本処理の後段に生物処理を適用することが可能となる。 In the fluorine-containing water treatment method of the present invention, the amount of calcium compound added to the sludge reforming tank is controlled based on not only the fluorine concentration in the raw water but also the calcium concentration in the reaction liquid. can be properly controlled. This also improves the quality of the treated water. In addition, since the calcium concentration in the treated water is low and calcium scale is suppressed, it becomes possible to apply biological treatment after this treatment.
実施の形態に係るフッ素含有水の処理装置の構成図である。1 is a configuration diagram of a fluorine-containing water treatment apparatus according to an embodiment; FIG.
　以下、図１を参照して実施の形態について説明する。 An embodiment will be described below with reference to FIG.
　図１は本発明方法を行うためのフッ素含有水の処理装置の実施の形態を示す系統図であり、図１中、１は、原水が原水配管１ａを介して導入される第１反応槽、２は第２反応槽、３は凝集槽、４は沈殿槽、５は汚泥改質槽を示す。原水配管１ａに、原水流量計２１と、原水のフッ素濃度を検出するためのフッ素イオン電極等よりなるフッ素センサ１６が設けられている。 FIG. 1 is a system diagram showing an embodiment of a fluorine-containing water treatment apparatus for carrying out the method of the present invention. In FIG. 2 indicates a second reaction tank, 3 a coagulation tank, 4 a sedimentation tank, and 5 a sludge reforming tank. The raw water pipe 1a is provided with a raw water flow meter 21 and a fluorine sensor 16 including a fluorine ion electrode or the like for detecting the fluorine concentration of the raw water.
　図１では、原水とカルシウム化合物との反応を２段に直列に配置した第１反応槽１と第２反応槽２とで行う。すなわち、第１反応槽１に汚泥改質槽５からの改質汚泥を添加するとともに、必要に応じてカルシウム化合物及びｐＨ調整剤を添加して、好ましくはｐＨ４～１０、より好ましくはｐＨ６～６．５にて原水中のフッ素の殆どを不溶化させる。第１反応槽１の流出液を第２反応槽２に導入し、必要に応じてｐＨ調整剤を添加して、好ましくはｐＨ４～１０、より好ましくはｐＨ６～６．５にて残留するフッ素を不溶化させる。なお、第２反応槽２でさらにフッ素を不溶化するため、ｐＨ調整剤の他にカルシウム化合物を添加することもある。 In FIG. 1, the reaction between the raw water and the calcium compound is carried out in the first reaction tank 1 and the second reaction tank 2 arranged in series in two stages. That is, the modified sludge from the sludge reforming tank 5 is added to the first reaction tank 1, and a calcium compound and a pH adjuster are added as necessary, preferably pH 4 to 10, more preferably pH 6 to 6. At 5, most of the fluorine in the raw water is insolubilized. The effluent of the first reaction tank 1 is introduced into the second reaction tank 2, and if necessary, a pH adjuster is added to remove residual fluorine at a pH of preferably 4 to 10, more preferably pH 6 to 6.5. Insolubilize. In addition, in order to further insolubilize fluorine in the second reaction tank 2, a calcium compound may be added in addition to the pH adjuster.
　この第２反応槽２にカルシウムイオン濃度を検出するためのカルシウムイオンセンサ等のカルシウムセンサ９が設けられている。なお、カルシウムセンサ９は、第２反応槽２の他に、第２反応槽２と凝集槽３との間の配管２ａ、または沈殿槽４の処理水以降の配管４ａに設けてもよい。 A calcium sensor 9 such as a calcium ion sensor for detecting the calcium ion concentration is provided in the second reaction tank 2 . In addition to the second reaction tank 2, the calcium sensor 9 may be installed in the pipe 2a between the second reaction tank 2 and the flocculation tank 3, or in the pipe 4a after the treated water of the sedimentation tank 4.
　この第２反応槽２の流出液は、凝集槽３に導入されて、高分子凝集剤が添加され凝集処理される。この高分子凝集剤としては、懸濁排水の凝集処理に用いられるものであれば特に制限されるものではないが、例えばポリアクリルアミド系高分子凝集剤などが用いられる。また、凝集効果を高めるため、ＰＡＣや硫酸バンドなどの無機凝集剤を添加後、高分子凝集剤を添加することも可能である。 The effluent from the second reaction tank 2 is introduced into the flocculation tank 3, added with a polymer flocculant, and flocculated. The polymer flocculant is not particularly limited as long as it is used for the flocculation treatment of suspended waste water, and for example, a polyacrylamide-based polymer flocculant is used. Moreover, in order to enhance the flocculation effect, it is possible to add a polymer flocculant after adding an inorganic flocculant such as PAC or aluminum sulfate.
　凝集槽３の凝集処理水は次いで、配管３ａを通って沈殿槽４に導入されて固液分離され、分離水が処理水として系外に排出される。分離汚泥は、その一部が返送汚泥として汚泥改質槽５に送給され、残部は余剰汚泥として系外へ排出される。 The flocculation treated water in the flocculation tank 3 is then introduced into the sedimentation tank 4 through the pipe 3a, solid-liquid separated, and the separated water is discharged out of the system as treated water. Part of the separated sludge is sent to the sludge reforming tank 5 as returned sludge, and the rest is discharged out of the system as excess sludge.
　汚泥改質槽５においてカルシウム化合物を添加して混合することにより、カルシウム化合物の少なくとも一部が汚泥の表面に吸着等により付着して汚泥が改質される。この改質汚泥が第１反応槽１に導入されると、汚泥表面のカルシウム化合物が原水中のフッ素と反応し、汚泥粒子が成長する。このように粒成長した汚泥は、沈降性が良好となるので、沈殿槽４において効率よく沈殿する。 By adding and mixing the calcium compound in the sludge reforming tank 5, at least part of the calcium compound adheres to the surface of the sludge by adsorption or the like, and the sludge is reformed. When this modified sludge is introduced into the first reaction tank 1, calcium compounds on the surface of the sludge react with fluorine in the raw water to grow sludge particles. The sludge that has undergone grain growth in this way has good sedimentation properties, and is efficiently sedimented in the sedimentation tank 4 .
　汚泥改質槽５に対しては、カルシウム化合物がカルシウム化合物含有液（例えば、消石灰（水酸化カルシウム）又は炭酸カルシウムの水スラリー、塩化カルシウム水溶液）の形態で添加される。カルシウム化合物含有液は、好ましくは消石灰スラリーであり、その濃度は２０ｗｔ％以下、望ましくは１０ｗｔ％である。塩化カルシウム水溶液は規格濃度（例えば３５ｗｔ％）で用いられる。 A calcium compound is added to the sludge reforming tank 5 in the form of a calcium compound-containing liquid (eg, water slurry of slaked lime (calcium hydroxide) or calcium carbonate, calcium chloride aqueous solution). The calcium compound-containing liquid is preferably slaked lime slurry, and its concentration is 20 wt % or less, desirably 10 wt %. A calcium chloride aqueous solution is used at a standard concentration (for example, 35 wt %).
　カルシウム化合物含有液は、ポンプ等により配管１０、開閉弁１１、配管１２、コントロール弁１３、配管１４を介して汚泥改質槽５に添加される。 The calcium compound-containing liquid is added to the sludge reforming tank 5 via a pipe 10, an on-off valve 11, a pipe 12, a control valve 13, and a pipe 14 by means of a pump or the like.
　コントロール弁１３は、開度（すなわちカルシウム化合物供給量）を連続的に変えることができるよう構成されたものであり、制御器１５によって開度が制御される。制御器１５は、カルシウムセンサ９と、原水のフッ素濃度を検出するためのフッ素イオン電極等よりなるフッ素センサ１６の検出信号と、原水配管の原水流量計２１の検出信号と、配管１２に設けられた流量計１７の検出信号とに基づいてコントロール弁１３の開度を制御する。 The control valve 13 is configured so that the degree of opening (that is, the amount of calcium compound supplied) can be changed continuously, and the degree of opening is controlled by the controller 15 . A controller 15 receives detection signals from a calcium sensor 9, a fluorine sensor 16 including a fluoride ion electrode or the like for detecting the fluorine concentration of raw water, a detection signal from a raw water flow meter 21 in the raw water pipe, and The opening of the control valve 13 is controlled based on the detection signal of the flow meter 17 .
　カルシウム化合物の添加量は、基本的には、第１反応槽１へのフッ素導入量（原水の流量と原水のフッ素濃度との積より求まる。）と当量となるように基準添加量を決定し、この基準添加量をカルシウムセンサ９の検出カルシウム濃度に基づいて補正して決定する。この補正の一例では、カルシウムセンサ９の検出カルシウム濃度が予め設定したカルシウム濃度目標値よりも低いときには、カルシウム濃度目標値と検出カルシウム濃度との差に応じてカルシウム化合物の添加量を増加させる。逆に、カルシウムセンサ９の検出カルシウム濃度が予め設定したカルシウム濃度目標値よりも高いときには、検出カルシウム濃度とカルシウム濃度目標値との差に応じてカルシウム化合物の添加量を減少させる。 The amount of the calcium compound to be added is basically determined so as to be equivalent to the amount of fluorine introduced into the first reaction tank 1 (obtained from the product of the flow rate of the raw water and the fluorine concentration of the raw water). , this reference addition amount is determined by correcting it based on the calcium concentration detected by the calcium sensor 9 . In one example of this correction, when the calcium concentration detected by the calcium sensor 9 is lower than a preset calcium concentration target value, the addition amount of the calcium compound is increased according to the difference between the calcium concentration target value and the detected calcium concentration. Conversely, when the calcium concentration detected by the calcium sensor 9 is higher than the preset calcium concentration target value, the addition amount of the calcium compound is reduced according to the difference between the detected calcium concentration and the calcium concentration target value.
　なお、この実施の形態では、コントロール弁１３の閉塞を防止するために、配管１２に対し洗浄水が、弁１８を有する配管１９を介して供給可能とされている。弁１１を閉とし、弁１８を開とすることにより、コントロール弁１３に洗浄水が通水され、コントロール弁１３がこの洗浄水で洗浄され、閉塞が防止される。この洗浄水によるコントロール弁１３の洗浄は、タイマーにより定期的に行われることが好ましく、例えば５分～２４時間に１回、特に１時間に１回程度の頻度で、また１回の洗浄水の通水時間は１～１０分、特に２分３０秒程度で行われるが、これに限定されない。洗浄水としては、水道水、工業用水などを用いることができる。 Note that in this embodiment, washing water can be supplied to the pipe 12 through a pipe 19 having a valve 18 in order to prevent the control valve 13 from being blocked. By closing the valve 11 and opening the valve 18, washing water is passed through the control valve 13, and the control valve 13 is washed with this washing water to prevent clogging. The cleaning of the control valve 13 with the cleaning water is preferably performed periodically by a timer, for example, once every 5 minutes to 24 hours, particularly once every hour. The water flow time is 1 to 10 minutes, particularly about 2 minutes and 30 seconds, but is not limited to this. Tap water, industrial water, or the like can be used as the washing water.
　このように、この実施の形態では、カルシウム化合物の添加量をカルシウムセンサ９の検出値で補正するので、カルシウム化合物溶液のカルシウム化合物濃度に変動があっても、適切なカルシウム化合物添加制御を行う。これにより、良好な水質の処理水を得ることが可能となり、例えば処理水中のフッ素濃度やカルシウム濃度を低くすることができる。また、これにより、処理水をリサイクルすることが容易となる。 Thus, in this embodiment, the amount of calcium compound added is corrected by the detection value of the calcium sensor 9, so even if the calcium compound concentration of the calcium compound solution fluctuates, appropriate calcium compound addition control is performed. Thereby, it becomes possible to obtain treated water of good quality, and for example, the fluorine concentration and calcium concentration in the treated water can be lowered. This also facilitates recycling of the treated water.
　この実施の形態では、コントロール弁１３が洗浄水で洗浄されるので、コントロール弁１３が閉塞することが防止され、安定した処理が可能である。 In this embodiment, since the control valve 13 is washed with washing water, the control valve 13 is prevented from being clogged and stable processing is possible.
　本開示を特定の態様を用いて詳細に説明したが、本開示の意図と範囲を離れることなく様々な変更が可能であることは当業者に明らかである。
　本出願は、２０２１年８月２３日付で出願された日本特許出願２０２１－１３５６９８に基づいており、その全体が引用により援用される。 Although the present disclosure has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications can be made without departing from the spirit and scope of the disclosure.
This application is based on Japanese Patent Application No. 2021-135698 filed on August 23, 2021, which is incorporated by reference in its entirety.
　１　第１反応槽
　２　第２反応槽
　３　凝集槽
　４　沈殿槽
　５　汚泥改質槽
　９　カルシウムセンサ
　１３　コントロール弁
　１５　制御器
　１６　フッ素センサ
　１７，２１　流量計

  1 first reaction tank 2 second reaction tank 3 flocculation tank 4 sedimentation tank 5 sludge reforming tank 9 calcium sensor 13 control valve 15 controller 16 fluorine sensor 17, 21 flow meter

Claims (5)

  1. 　フッ素含有水よりなる原水とカルシウム化合物を反応させて反応液を生成させる反応槽と、
    　この反応槽に原水を導入する原水路と、
    　反応槽から反応液を移送し高分子凝集剤を添加して凝集を行う凝集装置と、
    　凝集装置において形成されるフロックを含む混合液を導入して固液分離を行う固液分離槽と、
    　固液分離槽で分離された汚泥の一部を汚泥改質槽に導入し、カルシウム化合物をカルシウム化合物添加手段により添加して反応槽に循環させる循環路と
    を有するフッ素含有水の処理装置を用いたフッ素含有水の処理方法において、
    　原水のフッ素濃度及び原水流量と、前記反応液中のカルシウム濃度とに基づいて前記汚泥改質槽へのカルシウム化合物の添加量を制御することを特徴とするフッ素含有水の処理方法。     a reactor in which raw water made of fluorine-containing water and a calcium compound are reacted to generate a reaction liquid;
    A raw water channel for introducing raw water into the reaction tank;
    a flocculation device that transfers the reaction liquid from the reaction tank and adds a polymer flocculant to flocculate it;
    A solid-liquid separation tank for introducing a mixed liquid containing flocs formed in the flocculation device and performing solid-liquid separation;
    A portion of the sludge separated in the solid-liquid separation tank is introduced into the sludge reforming tank, a calcium compound is added by a calcium compound addition means, and a circulation path is used to circulate the sludge to the reaction tank. In the method for treating fluorine-containing water,
    A method for treating fluorine-containing water, wherein the amount of calcium compound added to the sludge reforming tank is controlled based on the fluorine concentration and flow rate of the raw water and the calcium concentration in the reaction liquid.
  2. 　前記反応槽として、原水及び前記汚泥改質槽からの汚泥が導入される第１反応槽と、該第１反応槽流出液が導入され、ｐＨ調整剤が添加される第２反応槽とが設けられており、原水のフッ素濃度及び原水流量と、該第２反応槽内又は該第２反応槽から流出する反応液中のカルシウム濃度とに基づいて前記汚泥改質槽へのカルシウム化合物添加量を制御することを特徴とする請求項１のフッ素含有水の処理方法。 As the reaction tanks, a first reaction tank into which raw water and sludge from the sludge reforming tank are introduced, and a second reaction tank into which the effluent from the first reaction tank is introduced and a pH adjuster is added are provided. The amount of calcium compound added to the sludge reforming tank is determined based on the fluorine concentration and raw water flow rate of the raw water and the calcium concentration in the reaction liquid in the second reaction tank or outflowing from the second reaction tank. 2. The method for treating fluorine-containing water according to claim 1, wherein controlling.
  3. 　前記第１反応槽へのフッ素導入量と当量となるように基準添加量を決定し、この基準添加量を該第２反応槽内又は該第２反応槽から流出する反応液中の検出カルシウム濃度に基づいて補正する請求項２のフッ素含有水の処理方法。 A reference addition amount is determined so as to be equivalent to the amount of fluorine introduced into the first reaction tank, and this reference addition amount is used as the detected calcium concentration in the second reaction tank or in the reaction solution flowing out of the second reaction tank. 3. The method for treating fluorine-containing water according to claim 2, wherein the correction is made based on
  4. 　前記補正として、前記反応液中のカルシウム濃度が予め設定したカルシウム濃度目標値よりも低いときには、カルシウム濃度目標値と検出カルシウム濃度との差に応じてカルシウム化合物の添加量を増加させ、前記反応液中の検出カルシウム濃度が予め設定したカルシウム濃度目標値よりも高いときには、検出カルシウム濃度とカルシウム濃度目標値との差に応じてカルシウム化合物の添加量を減少させる請求項３のフッ素含有水の処理方法。 As the correction, when the calcium concentration in the reaction solution is lower than a predetermined calcium concentration target value, the addition amount of the calcium compound is increased according to the difference between the calcium concentration target value and the detected calcium concentration, and the reaction solution is 4. The method for treating fluorine-containing water according to claim 3, wherein when the detected calcium concentration in the water is higher than a preset calcium concentration target value, the amount of calcium compound added is reduced according to the difference between the detected calcium concentration and the calcium concentration target value. .
  5. 　前記カルシウム化合物として水酸化カルシウムスラリーを添加することを特徴とする請求項１～４のいずれかのフッ素含有水の処理方法。

          5. The method for treating fluorine-containing water according to any one of claims 1 to 4, wherein calcium hydroxide slurry is added as said calcium compound.
PCT/JP2022/025086 2021-08-23 2022-06-23 Method for treating fluorine-containing water WO2023026661A1 (en)

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0615278A (en) * 1991-11-21 1994-01-25 Chubu Electric Power Co Inc Control of injection amount of slaked lime in treatment of fluorine-containing waste water and fluorine component removing apparatus
JP2009165990A (en) * 2008-01-18 2009-07-30 Kurita Water Ind Ltd Method for treating wastewater containing fluorine

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0615278A (en) * 1991-11-21 1994-01-25 Chubu Electric Power Co Inc Control of injection amount of slaked lime in treatment of fluorine-containing waste water and fluorine component removing apparatus
JP2009165990A (en) * 2008-01-18 2009-07-30 Kurita Water Ind Ltd Method for treating wastewater containing fluorine

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