JP2006218354A - Method for treating fluorine-containing waste water - Google Patents
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本発明は、フッ素含有廃水の処理方法に係り、特に、フッ素含有廃水中のフッ素をフッ化カルシウム法で除去するに当たり、過剰に添加したカルシウム化合物を炭酸カルシウムとして回収してフッ素除去工程で再利用することにより、余剰汚泥排出量を低減すると共に、薬品使用量を削減する方法に関する。 The present invention relates to a method for treating fluorine-containing wastewater. In particular, when removing fluorine in fluorine-containing wastewater by the calcium fluoride method, an excessively added calcium compound is recovered as calcium carbonate and reused in the fluorine removal step. The present invention relates to a method for reducing excess sludge discharge and reducing chemical usage.
半導体部品製造におけるシリコンウェハ製造工程から排出されるフッ素含有廃水、ステンレス鋼板製造工程から排出される酸洗廃水、アルミニウム表面処理廃水、フッ酸製造廃水、肥料製造廃水、ゴミ焼却廃水等のフッ素含有廃水の処理方法として、廃水にカルシウム化合物を添加して、廃水中のフッ化物イオンとカルシウムイオンとを反応させて不溶性塩であるフッ化カルシウムを生成させ、これを固液分離して処理水を得るフッ化カルシウム法が知られている（例えば非特許文献１）。フッ化カルシウム法は、より具体的には、フッ素含有廃水にカルシウム化合物を添加した後、中和剤を添加してｐＨ中性付近に調整し、フッ化物イオンとカルシウムイオンとの反応によりフッ化カルシウムの不溶性塩を生成させ、更に高分子凝集剤を添加して凝集処理し、その後固液分離する方法である。この方法において、カルシウム化合物としては一般に消石灰が用いられており、中和剤としては、硫酸や塩酸が用いられる。 Fluorine-containing wastewater discharged from silicon wafer manufacturing processes in semiconductor parts manufacturing, pickling wastewater discharged from stainless steel sheet manufacturing processes, aluminum surface treatment wastewater, hydrofluoric acid manufacturing wastewater, fertilizer manufacturing wastewater, waste incineration wastewater, etc. As a treatment method, a calcium compound is added to wastewater, and fluoride ions and calcium ions in the wastewater are reacted to produce calcium fluoride as an insoluble salt, which is solid-liquid separated to obtain treated water. A calcium fluoride method is known (for example, Non-Patent Document 1). More specifically, in the calcium fluoride method, after adding a calcium compound to fluorine-containing wastewater, a neutralizing agent is added to adjust the pH to near neutrality, and fluorination is performed by a reaction between fluoride ions and calcium ions. This is a method in which an insoluble salt of calcium is produced, a polymer flocculant is further added, and agglomeration treatment is performed, followed by solid-liquid separation. In this method, slaked lime is generally used as the calcium compound, and sulfuric acid or hydrochloric acid is used as the neutralizing agent.
このようなフッ化カルシウム法において添加するカルシウム化合物量は、廃水のフッ素濃度によって必要量が変化するが、通常、廃水中のフッ化物イオンをカルシウムイオンと十分に反応させてフッ素をなるべく多く除去するために、廃水中のフッ化物イオンからフッ化カルシウムを生成するのに必要なカルシウム当量よりも３００〜４００ｍｇ−Ｃａ／Ｌ程度過剰量のカルシウム化合物が添加される。 The amount of calcium compound added in such a calcium fluoride method varies depending on the fluorine concentration of the wastewater, but normally, fluoride ions in the wastewater are sufficiently reacted with calcium ions to remove as much fluorine as possible. For this reason, an excess amount of calcium compound of about 300 to 400 mg-Ca / L is added to the calcium equivalent necessary for generating calcium fluoride from fluoride ions in wastewater.
また、通常、各種の工程から排出されるフッ素含有廃水にはフッ素以外にも各種の有機物やアンモニア等も共存しているため、フッ素含有廃水の処理系には、これらの共存物質を除去するために、フッ素除去工程の後段に生物処理工程が設置されている。
フッ素含有廃水に消石灰等のカルシウム化合物を添加した後、硫酸、塩酸などの中和剤を用いてｐＨ中性に調整するフッ化カルシウム法では、フッ素の除去性を高めて処理水質を向上させるために、消石灰等のカルシウム化合物をフッ素の除去に必要な反応当量よりも過剰に添加すると、使用する消石灰量が多いだけでなく、中和に使用する中和剤量も多くなり、薬品コストが高くつく上に、更に、次のような課題がある。 After adding calcium compounds such as slaked lime to fluorine-containing wastewater, the calcium fluoride method is adjusted to neutral pH using neutralizing agents such as sulfuric acid and hydrochloric acid to improve the removal of fluorine and improve the quality of treated water In addition, adding calcium compounds such as slaked lime in excess of the reaction equivalent required for removing fluorine not only increases the amount of slaked lime used, but also increases the amount of neutralizing agent used for neutralization, resulting in high chemical costs. In addition, there are the following problems.
即ち、フッ素除去後の処理水は、通常、生物処理に供されるが、フッ化カルシウム法によるフッ素除去処理水中には、反応に使用されずに残留した余剰のカルシウムイオンが溶解した状態で存在している。 That is, the treated water after removal of fluorine is usually subjected to biological treatment, but the remaining calcium ions remaining in the fluorine-removed treated water by the calcium fluoride method are dissolved without being used in the reaction. is doing.
一方で、好気的な生物処理では、有機物の分解に伴って炭酸ガスが発生し、それらが曝気によって揮散するため、溶液中のｐＨが上昇することがある。このため、残留カルシウムイオンを含むフッ素除去処理水をこのような生物処理に供すると、ｐＨの上昇によってカルシウムが炭酸カルシウムとして配管、散気管、汚泥中で析出し、スケール発生を引き起こす。 On the other hand, in aerobic biological treatment, carbon dioxide gas is generated with the decomposition of organic substances, and they are volatilized by aeration, so that the pH in the solution may increase. For this reason, when the fluorine-removed treated water containing residual calcium ions is subjected to such biological treatment, calcium is precipitated as calcium carbonate in piping, aeration pipes, and sludge due to an increase in pH, causing scale generation.
嫌気的な生物処理においても、同様に炭酸が発生するため、炭酸カルシウムが発生する。また、窒素除去を行う場合には、脱窒反応によってｐＨが上昇し、炭酸カルシウムが析出することもある。 In the anaerobic biological treatment, since carbonic acid is similarly generated, calcium carbonate is generated. Moreover, when removing nitrogen, pH rises by denitrification reaction and calcium carbonate may precipitate.
このような炭酸カルシウム析出によるスケール障害を防ぐために、生物処理の前段にフッ素除去処理水中のカルシウムイオンを除去する工程を設置し、カルシウムイオンを炭酸カルシウムとして除去すると、大量の炭酸カルシウム汚泥が排出されることとなり、これを産業廃棄物として処分することが必要となる。 In order to prevent such scale failure due to precipitation of calcium carbonate, a process of removing calcium ions in the fluorine removal treated water is installed before biological treatment, and when calcium ions are removed as calcium carbonate, a large amount of calcium carbonate sludge is discharged. It becomes necessary to dispose of this as industrial waste.
本発明は、フッ素含有廃水中のフッ素をフッ化カルシウム法により除去する際の上記従来の課題を解決し、余剰カルシウムイオンの回収で排出される余剰汚泥量を低減すると共に、薬品使用量を削減するフッ素含有廃水の処理方法を提供することを目的とする。 The present invention solves the above-mentioned conventional problems in removing fluorine in fluorine-containing wastewater by the calcium fluoride method, reduces the amount of excess sludge discharged by recovery of excess calcium ions, and reduces the amount of chemicals used An object of the present invention is to provide a method for treating fluorine-containing wastewater.
本発明（請求項１）のフッ素含有廃水の処理方法は、フッ素含有廃水に、カルシウム化合物を添加して該フッ素含有廃水中のフッ化物イオンをフッ化カルシウムとして除去するフッ素含有廃水の処理方法において、該フッ素含有廃水に反応当量を超えるカルシウム化合物を添加して析出したフッ化カルシウムを除去するフッ素除去工程と、該フッ素除去工程を経た処理水から、該処理水中に残留するカルシウムイオンを炭酸カルシウムとして析出させ、この炭酸カルシウムの析出物を除去するカルシウム除去工程とを含むフッ素含有廃水の処理方法であって、前記フッ素除去工程は、フッ素含有廃水に炭酸カルシウムを添加して、フッ化カルシウムを析出させる第１工程と、第１工程を経た処理水に、該処理水のフッ化物イオンに対して反応当量を超える水溶性カルシウム化合物を添加して、フッ化カルシウムをさらに析出させ、該フッ化カルシウムの析出物を除去する第２工程とを備え、前記カルシウム除去工程における炭酸カルシウムの析出物を、該第１工程における炭酸カルシウムとして用いることを特徴とする。 The fluorine-containing wastewater treatment method of the present invention (Claim 1) is a fluorine-containing wastewater treatment method in which a calcium compound is added to fluorine-containing wastewater to remove fluoride ions in the fluorine-containing wastewater as calcium fluoride. Adding a calcium compound exceeding the reaction equivalent to the fluorine-containing wastewater to remove the precipitated calcium fluoride; and treating the calcium ions remaining in the treated water from the treated water that has undergone the fluorine removing process by calcium carbonate And a fluorine removal wastewater treatment method including a calcium removal step of removing the calcium carbonate precipitate, wherein the fluorine removal step adds calcium carbonate to the fluorine-containing wastewater, The first step of precipitation and the treated water that has undergone the first step react with fluoride ions of the treated water Adding a water-soluble calcium compound exceeding the amount, further precipitating calcium fluoride, and removing the calcium fluoride precipitate, the calcium carbonate precipitate in the calcium removal step, It is used as calcium carbonate in the first step.
請求項２のフッ素含有廃水の処理方法は、請求項１において、該カルシウム除去工程において、フッ素除去工程を経た処理水に炭酸ナトリウムを添加して、該処理水中に残留するカルシウムイオンを炭酸カルシウムとして析出させることを特徴とする。 The method for treating fluorine-containing wastewater according to claim 2 is the method according to claim 1, wherein in the calcium removal step, sodium carbonate is added to the treated water that has undergone the fluorine removal step, and calcium ions remaining in the treated water are converted into calcium carbonate. It is made to precipitate.
請求項３のフッ素含有廃水の処理方法は、請求項１において、該カルシウム除去工程において、フッ素除去工程を経た処理水に炭酸ガスを吹き込むことにより、該処理水中に残留するカルシウムイオンを炭酸カルシウムとして析出させることを特徴とする。 The method for treating fluorine-containing wastewater according to claim 3 is the method according to claim 1, wherein in the calcium removal step, carbon dioxide is blown into the treated water that has undergone the fluorine removal step, whereby calcium ions remaining in the treated water are converted into calcium carbonate. It is made to precipitate.
請求項４のフッ素含有廃水の処理方法は、請求項１ないし３のいずれか１項において、前記カルシウム除去工程を得た処理水を生物処理する生物処理工程を有することを特徴とする。 According to a fourth aspect of the present invention, there is provided a method for treating fluorine-containing wastewater according to any one of the first to third aspects, further comprising a biological treatment step of biologically treating the treated water obtained from the calcium removal step.
本発明によれば、フッ素除去工程の処理水中に残留するカルシウムイオンを炭酸カルシウムとして析出させて除去し、この炭酸カルシウム汚泥をフッ素除去工程のカルシウム源として再利用することにより余剰汚泥発生量を低減すると共に、薬品使用量を削減することができる。 According to the present invention, the calcium ions remaining in the treated water of the fluorine removal process are precipitated and removed as calcium carbonate, and this calcium carbonate sludge is reused as a calcium source in the fluorine removal process, thereby reducing the amount of excess sludge generated. In addition, the amount of chemicals used can be reduced.
本発明において、残留カルシウムイオンの除去は、フッ素除去工程の処理水に炭酸ナトリウムを添加して炭酸カルシウムを析出させ、これを分離する方法（請求項２）、或いはフッ素除去工程の処理水に炭酸ガスを吹き込み、晶析反応により炭酸カルシウム結晶を生成させる方法（請求項３）により行うことが好ましい。いずれの方法であっても、カルシウムイオンを炭酸カルシウム主体の無機汚泥として回収することができるため、これをそのままフッ素除去処理におけるＣａ源として再利用することができる。 In the present invention, residual calcium ions can be removed by adding sodium carbonate to the treated water in the fluorine removing step to precipitate calcium carbonate and separating it (Claim 2), or in the treated water in the fluorine removing step. It is preferably carried out by a method (claim 3) in which gas is blown and calcium carbonate crystals are produced by a crystallization reaction. In any method, since calcium ions can be recovered as inorganic sludge mainly composed of calcium carbonate, it can be reused as a Ca source in the fluorine removal treatment.
このような本発明のフッ素含有廃水の処理方法は、特に後段に生物処理工程を設け、フッ素除去処理水を生物処理する場合に有効であり、余剰汚泥発生量の低減、薬品使用量の削減を図った上で、生物処理工程における炭酸カルシウムスケールの発生を防止することができる。 Such a method for treating fluorine-containing wastewater according to the present invention is particularly effective when a biological treatment process is provided in the latter stage to biologically treat the fluorine-removed treated water, reducing the amount of excess sludge generated and reducing the amount of chemicals used. In addition, the occurrence of calcium carbonate scale in the biological treatment process can be prevented.
以下に図面を参照して本発明のフッ素含有廃水の処理方法の実施の形態を詳細に説明する。 Embodiments of a method for treating fluorine-containing wastewater according to the present invention will be described below in detail with reference to the drawings.
図１は本発明のフッ素含有廃水の処理方法の実施の形態を示す系統図である。 FIG. 1 is a system diagram showing an embodiment of a method for treating fluorine-containing wastewater according to the present invention.
［フッ素除去工程１］
〈第１工程１Ａ〉
本実施形態においては、フッ素含有廃水に、まず、後段のカルシウム除去工程２で回収された炭酸カルシウム汚泥を添加して、フッ素含有廃水中のフッ化物イオンと、炭酸カルシウム汚泥由来のカルシウムイオンとの反応でフッ化カルシウムを析出させる。
[Fluorine removal step 1]
<First step 1A>
In this embodiment, first, the calcium carbonate sludge collected in the subsequent calcium removal step 2 is added to the fluorine-containing wastewater, and the fluoride ions in the fluorine-containing wastewater and the calcium ions derived from the calcium carbonate sludge Calcium fluoride is precipitated by the reaction.
フッ素含有廃水中のフッ化物イオンを炭酸カルシウムと反応させるためには、炭酸カルシウムをフッ素含有廃水中に溶解させる必要があり、そのために系内は酸性条件であることが必要となる。従って、炭酸カルシウム汚泥をフッ素含有廃水中に添加した際にｐＨが高く、炭酸カルシウムが溶解しない場合には必要に応じて硫酸、塩酸等の酸を添加するなどして、系内をｐＨ３．０〜５．０程度の酸性とする。 In order to react the fluoride ions in the fluorine-containing wastewater with calcium carbonate, it is necessary to dissolve the calcium carbonate in the fluorine-containing wastewater. For this reason, the system must be in an acidic condition. Therefore, when calcium carbonate sludge is added to fluorine-containing wastewater, the pH is high. If calcium carbonate does not dissolve, an acid such as sulfuric acid or hydrochloric acid is added as necessary to adjust the pH of the system to 3.0. The acidity is about ˜5.0.
ただし、通常、フッ素含有廃水中はｐＨ０．５〜４．０程度の酸性であり、一般的には、このフッ素含有廃水にカルシウム除去工程からの炭酸カルシウム汚泥を添加するのみで炭酸カルシウムがフッ素含有廃水中に溶解しフッ化物イオンとカルシウムイオンとの反応でフッ化カルシウムが析出する。 However, normally, fluorine-containing wastewater is acidic at a pH of about 0.5 to 4.0. Generally, calcium carbonate is fluorine-containing simply by adding calcium carbonate sludge from the calcium removal process to this fluorine-containing wastewater. Dissolved in the wastewater, calcium fluoride is precipitated by the reaction between fluoride ions and calcium ions.
〈第２工程１Ｂ〉
上記第１工程１Ａ後は、更にフッ素含有廃水中に消石灰等の水溶性カルシウム化合物を添加し、必要に応じて塩酸、硫酸等の酸を添加してｐＨ６．０〜７．５、好ましくはｐＨ約７．０の中性にｐＨ調整することにより、更にフッ化カルシウムを析出させる。
<Second step 1B>
After the first step 1A, a water-soluble calcium compound such as slaked lime is further added to the fluorine-containing wastewater, and an acid such as hydrochloric acid or sulfuric acid is added as necessary to adjust the pH to 6.0 to 7.5, preferably pH. Calcium fluoride is further precipitated by adjusting the pH to about 7.0 neutral.
ここで、水溶性カルシウム化合物としては、通常、消石灰（Ｃａ（ＯＨ）２）が用いられるが、塩化カルシウム等の他の水溶性カルシウム化合物を用いることもできる。また、水溶性カルシウム化合物の２種以上を併用添加しても良い。 Here, slaked lime (Ca (OH) 2 ) is usually used as the water-soluble calcium compound, but other water-soluble calcium compounds such as calcium chloride can also be used. Two or more water-soluble calcium compounds may be added in combination.
水溶性カルシウム化合物は、水中のフッ化物イオンの反応当量よりも過剰量、好ましくは、反応当量の３００〜４００ｍｇ−Ｃａ／Ｌ程度過剰量となるように添加することが、フッ素の除去性を高める上で好ましい。 The water-soluble calcium compound is added in an excess amount, more preferably about 300 to 400 mg-Ca / L of the reaction equivalent of the fluoride ion in water, to improve the fluorine removability. Preferred above.
このようにして水溶性カルシウム化合物を添加してｐＨ調整した後は、所定時間、例えば１０〜３０分程度撹拌して凝集処理することが好ましい。 Thus, after adding water-soluble calcium compound and adjusting pH, it is preferable to agglomerate by stirring for a predetermined time, for example, about 10 to 30 minutes.
水溶性カルシウム化合物を添加してｐＨ中性に調整し、所定時間凝集処理した後は、好ましくは、更に高分子凝集剤を添加して凝集処理する。この高分子凝集剤としては、ポリアクリルアミド部分加水分解物、ポリアクリル酸ナトリウム、ポリビニルアミジン等の１種又は２種以上を用いることができ、その添加量は、処理対象水の水質や用いる高分子凝集剤によっても異なるが、通常０．１〜５ｍｇ／Ｌ程度である。 After the water-soluble calcium compound is added to adjust to pH neutrality and the aggregation treatment is performed for a predetermined time, preferably, a polymer flocculant is further added to perform the aggregation treatment. As the polymer flocculant, one or more of polyacrylamide partial hydrolyzate, sodium polyacrylate, polyvinylamidine and the like can be used, and the amount added is the quality of water to be treated and the polymer used. Although it varies depending on the flocculant, it is usually about 0.1 to 5 mg / L.
凝集処理液は次いで固液分離して処理水を得る。この固液分離には沈殿槽、膜分離装置等を用いることができる。 The coagulation treatment liquid is then subjected to solid-liquid separation to obtain treated water. For this solid-liquid separation, a precipitation tank, a membrane separation device, or the like can be used.
［カルシウム除去工程２］
上記フッ素除去工程１からの処理水は、過剰添加された水溶性カルシウム化合物由来の残留カルシウムイオンを含むものであるため、次いで、この残留カルシウムイオンを炭酸カルシウムとして除去する。
[Calcium removal step 2]
Since the treated water from the fluorine removal step 1 contains residual calcium ions derived from an excessively added water-soluble calcium compound, the residual calcium ions are then removed as calcium carbonate.
このカルシウム除去工程２における残留カルシウムイオンの除去方法としては特に制限はないが、フッ素除去処理水に炭酸ナトリウムを添加して炭酸カルシウムを析出させ、これを分離する方法、或いはフッ素除去処理水に炭酸ガスを吹き込み、晶析反応により炭酸カルシウム結晶を生成させる方法等が挙げられる。 Although there is no restriction | limiting in particular as the removal method of the residual calcium ion in this calcium removal process 2, The method of adding sodium carbonate to fluorine removal processing water, and precipitating calcium carbonate, or carbonation to fluorine removal processing water is carried out. Examples thereof include a method of blowing gas and generating calcium carbonate crystals by a crystallization reaction.
ここで、炭酸ナトリウムの添加量、炭酸ガスの吹き込み量は、フッ素除去処理水中に残留するカルシウムイオン量に応じて適宜決定される。 Here, the addition amount of sodium carbonate and the blowing amount of carbon dioxide gas are appropriately determined according to the amount of calcium ions remaining in the fluorine removal treated water.
このカルシウム除去工程２で分離される炭酸カルシウム汚泥は、前述のフッ素除去工程１の第１工程１Ａへ返送する。この炭酸カルシウム汚泥は、炭酸カルシウム（ＣａＣＯ３）を主体とする無機汚泥であるため、これをフッ素除去工程１のカルシウム源として有効に再利用することができる。 The calcium carbonate sludge separated in the calcium removal step 2 is returned to the first step 1A of the fluorine removal step 1 described above. Since this calcium carbonate sludge is an inorganic sludge mainly composed of calcium carbonate (CaCO 3 ), it can be effectively reused as a calcium source in the fluorine removal step 1.
なお、後段の生物処理工程における炭酸カルシウム析出のスケール障害を確実に防止するために、この除去工程においては、処理水中のカルシウムイオン濃度が４０〜５０ｍｇ／Ｌ以下となるようにカルシウムイオンを除去することが好ましい。 In order to surely prevent the scale failure of calcium carbonate precipitation in the subsequent biological treatment process, in this removal process, the calcium ions are removed so that the calcium ion concentration in the treated water is 40 to 50 mg / L or less. It is preferable.
［生物処理工程３］
本発明では、フッ素含有廃水に含まれている有機物や、アンモニア等の窒化化合物を除去するために、上記フッ素除去工程１及びカルシウム除去工程２を経た処理水を更に生物処理することが好ましい。
[Biological treatment process 3]
In the present invention, in order to remove organic compounds contained in the fluorine-containing wastewater and nitride compounds such as ammonia, it is preferable to further biologically treat the treated water that has undergone the fluorine removal step 1 and the calcium removal step 2.
この生物処理方式としては特に制限はないが、活性汚泥法、生物膜処理法等のすべての生物処理方式を適用することができ、好気、嫌気の処理方式のいずれでも良く、これらの併用であっても良い。 There are no particular restrictions on this biological treatment method, but all biological treatment methods such as the activated sludge method and the biofilm treatment method can be applied. Either an aerobic treatment method or an anaerobic treatment method may be used. There may be.
いずれの場合も前段でフッ化物イオン及びカルシウムイオンが除去されていることにより、フッ素による生物反応阻害や炭酸カルシウムによるスケール障害を引き起こすことなく、安定かつ効率的な生物処理を行える。 In any case, since fluoride ions and calcium ions are removed in the previous stage, stable and efficient biological treatment can be performed without causing biological reaction inhibition by fluorine and scale failure by calcium carbonate.
［処理方式］
本発明のフッ素含有廃水の処理方法は、図１に示す連続式に限らず、バッチ式でも行うことができるが、前述の如く、カルシウム除去工程からの炭酸カルシウムとフッ素含有廃水中のフッ化物イオンとを反応させるために、炭酸カルシウムをフッ素含有廃水中に溶解させるためには、ｐＨ酸性条件であることが必要であり、一方で、水溶性カルシウム化合物によるフッ化カルシウムの析出のためには、ｐＨ中性が好ましいことから、水溶性カルシウム化合物の添加に先立ち、カルシウム除去工程からの炭酸カルシウム汚泥の添加を行う必要があり、従って、バッチ式の場合には、水溶性カルシウム化合物よりも先に炭酸カルシウム汚泥を添加し、また、連続式の場合には、図に示す如く、水溶性カルシウム化合物の添加箇所よりも上流側で炭酸カルシウム汚泥を添加する必要がある。
[Processing method]
The fluorine-containing wastewater treatment method of the present invention is not limited to the continuous method shown in FIG. 1, but can also be performed in a batch manner. As described above, calcium carbonate from the calcium removal step and fluoride ions in the fluorine-containing wastewater. In order to dissolve calcium carbonate in the fluorine-containing wastewater, it is necessary to be under acidic pH conditions, while for precipitation of calcium fluoride by a water-soluble calcium compound, Since pH neutrality is preferable, it is necessary to add calcium carbonate sludge from the calcium removal step prior to the addition of the water-soluble calcium compound. Calcium carbonate sludge is added, and in the case of a continuous type, as shown in the figure, the charcoal is added upstream from the location where the water-soluble calcium compound is added. It is necessary to add calcium sludge.
このような本発明のフッ素含有廃水の処理方法は、半導体部品製造におけるシリコンウェハ製造工程から排出されるフッ素含有廃水、ステンレス鋼板製造工程から排出される酸洗廃水、アルミニウム表面処理廃水、フッ酸製造廃水、肥料製造廃水、ゴミ焼却廃水等の各種フッ素含有廃水の処理に有効である。 Such a fluorine-containing wastewater treatment method of the present invention includes fluorine-containing wastewater discharged from a silicon wafer manufacturing process in semiconductor component manufacturing, pickling wastewater discharged from a stainless steel sheet manufacturing process, aluminum surface treatment wastewater, and hydrofluoric acid manufacturing. It is effective for treating various fluorine-containing wastewater such as wastewater, fertilizer manufacturing wastewater, and waste incineration wastewater.
以下に比較例及び実施例を挙げて本発明をより具体的に説明する。 Hereinafter, the present invention will be described more specifically with reference to comparative examples and examples.
比較例１
〈フッ素除去工程〉
フッ素：１３０ｍｇ／Ｌ、有機酸：５０ｍｇ−ＴＯＣ／Ｌ、ＮＨ４−Ｎ：３０ｍｇ−Ｎ／Ｌ、ｐＨ２．０の電子産業廃水１０Ｌに対し、５５０ｍｇ／Ｌの消石灰を添加し、塩酸を用いてｐＨを７に調整した。３０ｍｉｎ撹拌して凝集処理した後、高分子凝集剤を１ｍｇ／Ｌ添加して固液分離を行った。発生したフッ化カルシウム汚泥量は約１．３ｇでフッ素除去処理水のフッ素濃度は１５ｍｇ／Ｌであった。
Comparative Example 1
<Fluorine removal process>
Fluorine: 130 mg / L, organic acid: 50 mg-TOC / L, NH 4 -N: 30 mg-N / L, and pH 2.0 electronic industrial wastewater 10 L, 550 mg / L slaked lime was added and hydrochloric acid was used. The pH was adjusted to 7. After stirring for 30 minutes for aggregation treatment, 1 mg / L of a polymer flocculant was added to perform solid-liquid separation. The amount of generated calcium fluoride sludge was about 1.3 g, and the fluorine concentration of the fluorine removal treated water was 15 mg / L.
〈カルシウム除去工程〉
フッ素除去工程の処理水に炭酸ナトリウム１７００ｍｇ／Ｌを添加して凝集処理した後固液分離を行った。発生した炭酸ナトリウム汚泥量は約４ｇで、カルシウム除去処理水のカルシウム濃度は３０ｍｇ／Ｌであった。
<Calcium removal process>
After 1700 mg / L of sodium carbonate was added to the treated water in the fluorine removal step and agglomeration treatment was performed, solid-liquid separation was performed. The amount of generated sodium carbonate sludge was about 4 g, and the calcium concentration of the calcium removal treated water was 30 mg / L.
〈生物処理工程〉
カルシウム除去処理水を活性汚泥処理に供し、有機物の分解と窒素の除去処理を行った。
<Biological treatment process>
The calcium removal treated water was subjected to activated sludge treatment to decompose organic matter and remove nitrogen.
各工程で得られた処理水の水質は表１に示す通りであった。 The quality of the treated water obtained in each step was as shown in Table 1.
実施例１
比較例１において、カルシウム除去工程で発生した炭酸カルシウム汚泥約４ｇを比較例１で処理したものと同様の電子産業廃水１０Ｌに添加し（このときのｐＨは３．０であった。）、その後３７０ｍｇ／Ｌの消石灰を添加し、塩酸を用いてｐＨを７に調整した。３０ｍｉｎ撹拌して凝集処理した後、高分子凝集剤を１ｍｇ／Ｌ添加して固液分離を行った。その後、比較例１と同様にカルシウム除去工程、生物処理工程を行い、得られた処理水の水質を汚泥発生量、消石灰及び塩酸使用量と共に表１に示した。
Example 1
In Comparative Example 1, about 4 g of calcium carbonate sludge generated in the calcium removal step was added to 10 L of electronic industry wastewater similar to that treated in Comparative Example 1 (the pH at this time was 3.0), and thereafter. 370 mg / L of slaked lime was added, and the pH was adjusted to 7 using hydrochloric acid. After stirring for 30 minutes for aggregation treatment, 1 mg / L of a polymer flocculant was added to perform solid-liquid separation. Then, the calcium removal process and the biological treatment process were performed similarly to the comparative example 1, and the quality of the obtained treated water was shown in Table 1 with sludge generation amount, slaked lime, and hydrochloric acid usage.
表１より明らかなように、本発明によれば、最終処理水の水質に影響を及ぼすことなく、余剰の炭酸カルシウム汚泥をなくし、また消石灰の使用量を大幅に削減した上で、良好な処理を行える。 As is clear from Table 1, according to the present invention, the surplus calcium carbonate sludge is eliminated without affecting the quality of the final treated water, and the amount of slaked lime used is greatly reduced, and a good treatment is achieved. Can be done.
１ フッ素除去工程
１Ａ 第１工程
１Ｂ 第２工程
２ カルシウム除去工程
３ 生物処理工程
DESCRIPTION OF SYMBOLS 1 Fluorine removal process 1A 1st process 1B 2nd process 2 Calcium removal process 3 Biological treatment process
Claims (4)
該フッ素含有廃水に反応当量を超えるカルシウム化合物を添加して析出したフッ化カルシウムを除去するフッ素除去工程と、
該フッ素除去工程を経た処理水から、該処理水中に残留するカルシウムイオンを炭酸カルシウムとして析出させ、この炭酸カルシウムの析出物を除去するカルシウム除去工程とを含むフッ素含有廃水の処理方法であって、
前記フッ素除去工程は、
フッ素含有廃水に炭酸カルシウムを添加して、フッ化カルシウムを析出させる第１工程と、
第１工程を経た処理水に、該処理水のフッ化物イオンに対して反応当量を超える水溶性カルシウム化合物を添加して、フッ化カルシウムをさらに析出させ、フッ化カルシウムの析出物を除去する第２工程とを備え、
前記カルシウム除去工程における炭酸カルシウムの析出物を、該第１工程における炭酸カルシウムとして用いることを特徴とするフッ素含有廃水の処理方法。 In a method for treating fluorine-containing wastewater, a calcium compound is added to fluorine-containing wastewater to remove fluoride ions in the fluorine-containing wastewater as calcium fluoride.
A fluorine removal step of removing calcium fluoride precipitated by adding a calcium compound exceeding a reaction equivalent to the fluorine-containing wastewater;
A treatment method for fluorine-containing wastewater, comprising: from the treated water that has undergone the fluorine removal step, precipitated calcium ions remaining in the treated water as calcium carbonate, and removing the calcium carbonate precipitate;
The fluorine removal step
A first step of adding calcium carbonate to fluorine-containing wastewater to precipitate calcium fluoride;
A water-soluble calcium compound that exceeds the reaction equivalent to the fluoride ions of the treated water is added to the treated water that has undergone the first step to further precipitate calcium fluoride, and to remove the calcium fluoride precipitate. With two steps,
A method for treating fluorine-containing wastewater, wherein a precipitate of calcium carbonate in the calcium removal step is used as calcium carbonate in the first step.
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009165990A (en) * | 2008-01-18 | 2009-07-30 | Kurita Water Ind Ltd | Method for treating wastewater containing fluorine |
| JP2010082546A (en) * | 2008-09-30 | 2010-04-15 | Japan Organo Co Ltd | Water treatment apparatus and method |
| CN102897954A (en) * | 2011-07-26 | 2013-01-30 | 兆联实业股份有限公司 | Method and equipment for recovering and treating ammonia-containing wastewater |
| CN104528908A (en) * | 2014-12-12 | 2015-04-22 | 瓮福（集团）有限责任公司 | Method for removing fluorine in acidic wastewater by using lime serving as byproduct |
| KR102190985B1 (en) * | 2020-06-04 | 2020-12-14 | 최윤진 | Method of recovering high purity calcium difluoride particles with large particle size from waste water including fluorine compounds with ammonium ions by using organic acids |
| CN116425373A (en) * | 2023-06-13 | 2023-07-14 | 长春柏美水务科技有限公司 | System for high fluorine-containing waste water advanced treatment resourceful treatment of high pH |
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| JP2003311279A (en) * | 2002-04-23 | 2003-11-05 | Kurita Water Ind Ltd | Apparatus and method for treating waste water |
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| JPS5267152A (en) * | 1975-12-02 | 1977-06-03 | Mitsui Toatsu Chem Inc | Continuously treating method of exhaust liquid containing fluorine and phosphoric acid ions |
| JP2001276851A (en) * | 2000-03-29 | 2001-10-09 | Japan Organo Co Ltd | Drain treatment equipment |
| JP2003311279A (en) * | 2002-04-23 | 2003-11-05 | Kurita Water Ind Ltd | Apparatus and method for treating waste water |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009165990A (en) * | 2008-01-18 | 2009-07-30 | Kurita Water Ind Ltd | Method for treating wastewater containing fluorine |
| JP2010082546A (en) * | 2008-09-30 | 2010-04-15 | Japan Organo Co Ltd | Water treatment apparatus and method |
| CN102897954A (en) * | 2011-07-26 | 2013-01-30 | 兆联实业股份有限公司 | Method and equipment for recovering and treating ammonia-containing wastewater |
| CN104528908A (en) * | 2014-12-12 | 2015-04-22 | 瓮福（集团）有限责任公司 | Method for removing fluorine in acidic wastewater by using lime serving as byproduct |
| KR102190985B1 (en) * | 2020-06-04 | 2020-12-14 | 최윤진 | Method of recovering high purity calcium difluoride particles with large particle size from waste water including fluorine compounds with ammonium ions by using organic acids |
| CN116425373A (en) * | 2023-06-13 | 2023-07-14 | 长春柏美水务科技有限公司 | System for high fluorine-containing waste water advanced treatment resourceful treatment of high pH |
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