JP4058787B2 - Method for treating boron-containing water - Google Patents

Method for treating boron-containing water Download PDF

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JP4058787B2
JP4058787B2 JP33912297A JP33912297A JP4058787B2 JP 4058787 B2 JP4058787 B2 JP 4058787B2 JP 33912297 A JP33912297 A JP 33912297A JP 33912297 A JP33912297 A JP 33912297A JP 4058787 B2 JP4058787 B2 JP 4058787B2
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Prior art keywords
boron
water
ion exchange
concentration
evaporation
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JPH11169864A (en
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良弘 恵藤
裕之 朝田
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Kurita Water Industries Ltd
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Kurita Water Industries Ltd
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Description

【0001】
【発明の属する技術分野】
本発明はホウ素含有水の処理方法に関し、特に蒸発濃縮およびイオン交換によるホウ素含有水の処理方法に関するものである。
【0002】
【従来の技術】
ホウ素化合物は種々の分野で使用されており、これらの分野から発生する排水、あるいは他の分野で発生する排水にはホウ素化合物を含むものがある。このような化合物は有害とされているため、ホウ素含有水からホウ素を除去するための処理が行われている。
【0003】
従来のホウ素含有水の処理方法として、アルミニウム化合物およびカルシウム化合物を用いて凝集沈殿によりホウ素を分離除去する方法が行われている(特公昭58−15193号、同59−24876号)。しかしこの方法では多量の薬剤を使用する必要があり、発生汚泥量も多く、その処理が困難であるという問題点がある。
【0004】
またホウ素含有水をアニオン交換樹脂によりイオン交換してホウ素を除去し、アニオン交換樹脂の再生排液を蒸発濃縮して処理する方法も知られている(特公平1−43594号)。しかしこの方法では原水を直接イオン交換するため、多量のイオン交換樹脂を使用する必要があり、再生頻度が高く、再生剤の使用量も多くなり、また蒸発濃縮により生成する凝縮水中のホウ素の処理については示されていない。
【0005】
このほかホウ素含有水を逆浸透(以下、ROという場合がある)膜装置において膜分離し、濃縮液を蒸発濃縮し、RO膜装置の透過液と蒸発濃縮による凝縮液をイオン交換樹脂で処理する方法が示されている(特開昭59−49898号)。しかしこの方法では、RO膜のホウ素除去率が最高でも約60%程度と低いため、多量の樹脂量および薬剤使用量が必要となる。
【0006】
この方法では再生排液を原水と混合して処理できるとしているが、再生排液を原水と混合してRO膜装置で処理すると、透過液のホウ素濃度は原水の約1.5倍程度になるため、原水を直接イオン交換する場合よりも多量の樹脂と再生剤量を必要とし、再生頻度も高くなるという問題点がある。
【0007】
【発明が解決しようとする課題】
本発明の課題は、イオン交換樹脂および薬剤の使用量を少なくし、イオン交換樹脂の再生排液も排出することなく、ホウ素を効率よく高除去率で除去して高水質の処理水を得ることができ、汚泥発生量も少なくできるホウ素含有水の処理方法を得ることである。
【0008】
【課題を解決するための手段】
本発明は次のホウ素含有水の処理方法である。
(1) ホウ素が1000〜10000mg/l含まれているホウ素含有水を、RO膜処理を行うことなく、蒸発濃縮により凝縮水と濃縮物に分離する蒸発濃縮工程と、
凝縮水をN−メチルグルカミン型のキレート樹脂からなるイオン交換樹脂と接触させてホウ素を除去するイオン交換工程と、
イオン交換樹脂を酸で再生し、再生排液を蒸発濃縮工程に戻す再生工程と
を含むホウ素含有水の処理方法。
(2) 再生排液を原水と混合し、中性以上のpHに調整して蒸発濃縮工程で蒸発濃縮する上記(1)記載の方法。
【0009】
本発明において処理の対象となるホウ素含有水は通常オルトホウ酸(HBO)の形でホウ素を含有する水であるが、ホウ酸塩その他の形でホウ素を含むものでもよい。このようなホウ素含有水としては、医薬、化粧品、石けん、その他のホウ素化合物を使用する製造工程排水、メッキ排水、原子力発電所から発生する放射性排水、地熱発電排水、排煙脱硫排水、ゴミ焼却場の洗煙排水などがあげられる。これらのホウ素含有水としては、ホウ素が1000〜10000mg/l含まれているものが処理の対象となる
【0010】
これらのホウ素含有水はそのまま本発明の処理を行ってもよく、また他の成分を除去する処理を行ったのち、本発明の処理を行ってもよい。原水が固形物その他のスケール成分、腐食成分を含む場合は凝集沈殿、濾過等の前処理により、これらの他の成分を除去するのが好ましい。
【0011】
凝集沈殿処理はアルミニウム塩、鉄塩等の凝集剤および必要により水酸化カルシウム等のアルカリ剤を加えて凝集を行い、固液分離することにより、固形物その他の凝集可能な成分を除去する操作である。濾過は凝集濾過のほか、固形物分離のための一般的な濾過を含む。
【0012】
前処理としてはこのような固形物除去など、蒸発濃縮を阻害する物質を除去する範囲で行えばよいが、ホウ素以外の成分をすべて除去しておくと、後の工程でホウ素を純粋な形で回収することができる。前処理ではホウ素は除去されてもよく、また除去されなくてもよい。また前処理として、蒸発濃縮工程の負荷を軽減するような濃縮操作を行ってもよいが、本発明ではRO膜処理を行うことなく、蒸発濃縮工程で濃縮を行う。またRO膜処理以外にも、ホウ素分離が不完全な濃縮操作を行うことなく、蒸発濃縮工程において濃縮を行うことができる
【0013】
蒸発濃縮工程はホウ素含有水をイオン交換樹脂の再生排液とともに蒸発させて濃縮し、ホウ素化合物を濃縮する。蒸発濃縮工程には、加熱蒸発、真空蒸発、これらの組合せなど任意の蒸発装置を採用できるが、加熱蒸発が好ましい。各蒸発装置の形式もフラッシュタイプ、フィルムタイプなど、任意の形式の蒸発装置を使用することができる。
【0014】
これらの蒸発装置にホウ素含有水、その前処理水等の被処理水およびイオン交換樹脂の再生排液を導入して水分を蒸発させ、蒸気を凝縮して凝縮水を生成させる。凝縮のための冷却水として原水を用いて熱回収することにより、少ない熱量で効率よく蒸発濃縮を行うことができる。水分の蒸発により液側にはホウ素化合物その他非揮発性成分が濃縮され、濃縮物が得られる。
【0015】
このときの濃縮倍率は原水濃度および濃縮液の処分方法を考慮して決定する。濃縮物は固形物または液状物の状態で得、そのままの状態で回収または処分することができるほか、セメント等で硬化して処分することもできる。また濃縮液の状態で得て凝集等により後処理することもできる。いずれの場合も純粋な形でホウ素化合物が得られる場合は回収して利用することが可能である。
【0016】
蒸発濃縮工程で得られる凝縮水には、蒸気に同伴して移行した1〜10mg/l程度のホウ素が含まれているので、この凝縮水をイオン交換工程においてイオン交換樹脂と接触させてホウ素を除去する。凝縮水に含まれるホウ素は原水の1/100〜1/10000程度になっているので、ここで使用する樹脂量および再生剤量も原水を直接イオン交換する場合に比べてその割合で少なくすることができる。
【0017】
イオン交換工程で使用するイオン交換樹脂は、ホウ素を除去するためにN−メチルグルカミン型のキレート樹脂からなるアニオン交換樹脂を使用するが、カチオンを除去する必要がある場合にはカチオン交換樹脂も使用することができ、この場合は混床で処理するのが好ましい。
【0018】
ホウ素を除去するためのアニオン交換樹脂は、ホウ素の吸着量を高めたキレート樹脂として、ホウ素を選択的に吸着するN−メチルグルカミン型の樹脂を用いると、ホウ素の除去率が高くなるほか、回収ホウ素化合物(ホウ酸)の純度が高くなる。
【0019】
イオン交換工程では、N−メチルグルカミン型のキレート樹脂からなるイオン交換樹脂を充填した樹脂層に凝縮水を通水してイオン交換を行いホウ素を交換吸着する。凝縮水に含まれるホウ素は大部分がオルトホウ酸であり、水中では(1)式により解離していると考えられている。
【化1】
BO+HO=B(OH) +H・・・・(1)
【0020】
(1)式における平衡はpHによって変化し、pHが高いほど平衡が右にずれる傾向にある。この場合キレート樹脂がSO4形の場合は、pH9以上でないと処理困難であり、またOH形の場合は、中性付近においても処理できるが、とくにpH9以上とすることによりイオン交換量が増大するので好ましい。
【0021】
イオン交換工程において、ホウ素含有水をキレート樹脂と接触させることにより、上記B(OH) -が樹脂に交換吸着され除去される。処理水はホウ素その他のアニオンが除去され、純水に近い高純度の処理水が得られ、そのまま利用可能である。凝縮水にカチオンが含まれる場合は、前述のようにカチオン交換樹脂で処理することによりカチオンを除去することができ、またキレート樹脂として他のアニオンも除去する樹脂を用いて処理する場合はこれにより処理水として純水を得ることができる。
【0022】
キレート樹脂がホウ素で飽和した場合、再生工程に移って樹脂層を逆洗し、さらに再生剤を通液して交換吸着したホウ素を溶離させる。再生剤としては、酸、アルカリなど一般的な再生剤を用いることができるが、特に硫酸、塩酸または硝酸を用いるのが好ましい。再生剤の通液によりホウ素が溶離し、高濃度ホウ素を含有する再生排液が発生する。ホウ素の溶離を終った樹脂は、必要により水酸化ナトリウムでOH形にしたのち、再びホウ素の吸着に用いることができる。
【0023】
再生排液はそのまま、またはpH調整して原水と混合して蒸発濃縮工程に戻す。蒸発濃縮工程ではpHが低いほど、オルトホウ酸が蒸気側に移行しやすいので、中性以上のpHで蒸発濃縮工程に導入するのが好ましい。原水が酸性またはアルカリ性であって、再生排液を混合することにより中性以上のpHとなる場合は、これらを単に混合するだけでよい。これらを混合して中性以上にならない場合にはpH調整剤として酸またはアルカリを添加するのが好ましい。再生剤として酸およびアルカリを用いる場合は、もちろんこれらを混合して蒸発濃縮工程に戻す。
【0024】
再生排液を原水と混合した被処理水を蒸発濃縮工程で蒸発濃縮することにより、再生排液に含まれる濃縮されたホウ素その他の物質は濃縮されて回収または処分される。また再生排液の混合により被処理のホウ素濃度が高くなり、その分凝縮水側に移行するホウ素の量も多くなるが、これらはイオン交換工程において除去される。
【0025】
蒸発濃縮工程に供給する被処理水の水質はできるだけ安定している方が蒸発濃縮工程の運転上好ましいが、このためには間欠的に排出される再生排液を貯槽に貯留しておき、蒸発濃縮工程に一定量ずつ戻すのが好ましい。またイオン交換樹脂の再生中にも蒸発濃縮工程は運転が続けられるので、その間に生成する凝縮水を貯留して処理量を均質化したり、あるいはイオン交換装置を複数個設けて切換により処理を連続的に行うようにするのが好ましい。
【0026】
上記の処理では、予め蒸発濃縮によりホウ素を濃縮し、ホウ素含量の少ない凝縮水のみをイオン交換するため、イオン交換樹脂および再生剤量が少なくてすみ、かつホウ素除去率を高くして高水質で純水に近い水質の処理水を得ることができる。またイオン交換樹脂の再生排液を蒸発濃縮工程に戻して蒸発濃縮するため、再生排液の処理が容易であり、発生する汚泥量も少なくなる。
【0027】
【発明の効果】
本発明によれば、ホウ素が1000〜10000mg/l含まれているホウ素含有水を、RO膜処理を行うことなく、蒸発濃縮により凝縮水と濃縮物に分離する蒸発濃縮工程と、凝縮水をN−メチルグルカミン型のキレート樹脂からなるイオン交換樹脂と接触させてホウ素を除去するイオン交換工程と、イオン交換樹脂を酸で再生し、再生排液を蒸発濃縮工程に戻す再生工程とを含むので、イオン交換樹脂および薬剤の使用量を少なくし、イオン交換樹脂の再生排液も排出することなく、ホウ素を効率よく高除去率で除去して高水質の処理水を得ることができ、汚泥発生量も少なくすることができる。
【0028】
【発明の実施の形態】
以下、本発明の実施の形態を図面に基づいて説明する。
図1は本発明の実施形態によるホウ素含有水の処理方法を示す系統図である。図1において、1は調整槽、2は蒸発濃縮装置、3はイオン交換槽、4は排液貯槽である。
【0029】
上記の装置によるホウ素含有水の処理方法は以下の通りである。まず調整槽1に原水路5から原水を導入し、排液供給路6から再生排液を導入して攪拌機7で攪拌して混合し、必要により薬注路8からpH調整剤を注入して、中性以上のpHに調整する。調整槽1内の混合液を被処理液として系路9から蒸発濃縮装置2に導入する。
【0030】
蒸発濃縮装置2は加熱蒸発式に構成されており、供給される被処理液を加熱蒸発させ、発生する蒸気を凝縮して凝縮水を得、この凝縮水を系路10からイオン交換槽3に送り、一方濃縮液を濃縮液路11から取出す。ここでは蒸発によりホウ素は濃縮液側に濃縮され、一部は凝縮液側に移行する。蒸気は被処理液により冷却して熱回収するように構成されているが、詳細な図示は省略されている。
【0031】
イオン交換槽3はN−メチルグルカミン型のキレート樹脂を充填した樹脂層12を有しており、イオン交換工程において樹脂層12に凝縮水を通水することによりホウ素を交換吸着させて除去し、処理水を処理水路13から取り出す。イオン交換槽3は複数個設けることにより、イオン交換工程の終了により再生工程に移る際、切換えて連続処理を行う。
【0032】
薬注路14から再生剤を注入して樹脂層12を再生し、再生排液を系路15から排液貯槽4に送る。再生剤としては酸とアルカリを順次流すことにより再生効率を高めることができる。この場合これらの排液を排液貯槽4に集め攪拌機16で攪拌することにより中和を行い、均質化流量で排液供給路6から調整槽1に供給する。
【0033】
【実施例1】
以下、本発明の実施例および比較例について説明する。
【0034】
実施例1
ホウ素を2500mg/l含むpH7.0の原水を、蒸発濃縮装置において100℃に加熱して濃縮倍数15倍で蒸発濃縮を行い、ホウ素濃度7.1mg/lの凝縮水を得た。この凝縮水をN−メチルグルカミン型ホウ素選択吸着樹脂(三菱化学社製ダイヤイオンCRB−02、商標)の樹脂層にSV2hr-1で通水したところ、440BVまでホウ素1mg/l以下の処理水が得られた。
【0035】
上記樹脂層を100g/l硫酸で再生したところ、ホウ素濃度2450mg/lの再生排液が得られた。この再生排液を中和することなく原水に混合したところpH3となり、これを蒸発濃縮装置において濃縮倍数15倍に濃縮したところ、凝縮水のホウ素濃度は26mg/lとなった。この凝縮水を前記と同様に樹脂層通水したところ、120BVまでホウ素濃度1mg/l以下の処理水が得られた。
【0036】
実施例2
実施例1において、再生排液に水酸化ナトリウムを添加してpH7.0に調整し、原水1 literに対し、中和した再生排液を3mlの割合で混合して蒸発濃縮したところ、濃縮倍率15倍における凝縮水のホウ素濃度は6.9mg/lになった。この凝縮水を実施例1と同様にイオン交換処理したところ、BV440までホウ素濃度1mg/l以下の処理水が得られた。
また上記蒸発濃縮工程における濃縮液を乾燥して得られた固形物は、原水1 literあたり25gであった。
【0037】
比較例1
実施例1と同じ排水をホウ素選択樹脂にSV2hr-1で通液したところ1.5BVまで1mg/l以下の処理水が得られた。また、ホウ素を吸着した樹脂を100g/l硫酸で再生したところ、ホウ素を2480mg/l含有する再生排液が得られた。この場合必要樹脂量は実施例1に比べ300倍程度となり、再生剤および再生排液中和用アルカリ剤量も実施例に比べ約300倍量必要であった。このため再生排液量は原水量とほぼ同等であり、再生排液を蒸発濃縮する場合蒸発装置容量は実施例1と同等となった。
【0038】
比較例2
比較例1で得られた再生排液を硫酸バンド45g/lおよび消石灰150g/l添加(pH12.4)30分攪拌後固液分離したところ、ホウ素含有量180mg/lの処理水が得られた。その際の固形物発生量は220g/l−原水であった。一方、実施例2において生成する固形物はわずか25g/l−原水であり、大幅に低減している。
【図面の簡単な説明】
【図1】実施形態のホウ素含有水の処理方法を示す系統図である。
【符号の説明】
1 調整槽
2 蒸発濃縮装置
3 イオン交換槽
4 排液貯槽
5 原水路
6 排液供給路
7、16 攪拌機
8、14 薬注路
11 濃縮液路
13 処理水路
[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for treating boron-containing water, and more particularly to a method for treating boron-containing water by evaporation and ion exchange.
[0002]
[Prior art]
Boron compounds are used in various fields, and some wastewaters generated from these fields or other fields include boron compounds. Since such a compound is considered harmful, a treatment for removing boron from the boron-containing water is performed.
[0003]
As a conventional method for treating boron-containing water, a method of separating and removing boron by coagulation precipitation using an aluminum compound and a calcium compound has been carried out (Japanese Patent Publication Nos. 58-15193 and 59-24876). However, this method has a problem that it is necessary to use a large amount of chemicals, the amount of generated sludge is large, and the treatment is difficult.
[0004]
In addition, a method is also known in which boron is removed by ion exchange of boron-containing water with an anion exchange resin, and the regenerated effluent of the anion exchange resin is evaporated and concentrated (Japanese Patent Publication No. 1-35944). However, in this method, since raw water is directly ion-exchanged, it is necessary to use a large amount of ion-exchange resin, the frequency of regeneration is high, the amount of regenerant used is large, and the treatment of boron in condensed water generated by evaporation and concentration Is not shown.
[0005]
In addition, the boron-containing water is subjected to membrane separation in a reverse osmosis (hereinafter sometimes referred to as RO) membrane device, the concentrated solution is evaporated and concentrated, and the permeated solution of the RO membrane device and the condensed solution obtained by evaporation and concentration are treated with an ion exchange resin. A method is shown (Japanese Patent Laid-Open No. 59-49898). However, in this method, since the boron removal rate of the RO membrane is as low as about 60% at the maximum, a large amount of resin and amount of drug used are required.
[0006]
In this method, the recycled wastewater can be mixed with the raw water and processed. However, when the recycled wastewater is mixed with the raw water and processed by the RO membrane device, the boron concentration of the permeate becomes about 1.5 times the raw water. Therefore, there is a problem that a larger amount of resin and regenerant are required than in the case of direct ion exchange of raw water, and the regeneration frequency is increased.
[0007]
[Problems to be solved by the invention]
An object of the present invention is to obtain a high-quality treated water by efficiently removing boron at a high removal rate without reducing the amount of ion-exchange resin and chemicals used, and without discharging the regeneration drainage of the ion-exchange resin. It is possible to obtain a method for treating boron-containing water that can reduce the amount of sludge generated.
[0008]
[Means for Solving the Problems]
The present invention is the following method for treating boron-containing water.
(1) An evaporative concentration step in which boron-containing water containing 1000 to 10000 mg / l of boron is separated into condensed water and concentrate by evaporative concentration without performing RO membrane treatment ;
An ion exchange step of contacting the condensed water with an ion exchange resin comprising an N-methylglucamine type chelate resin to remove boron;
To regenerate the ion exchange resin with acid, how to process the boron-containing water and a regeneration step of returning the playback drainage in evaporation process.
(2) The method according to (1) above, wherein the regenerated effluent is mixed with raw water, adjusted to a neutral or higher pH, and evaporated and concentrated in an evaporation and concentration step.
[0009]
The boron-containing water to be treated in the present invention is usually water containing boron in the form of orthoboric acid (H 3 BO 3 ), but may also contain boron in other forms of borate. Such boron-containing water includes pharmaceutical, cosmetics, soap, and other process wastewaters that use boron compounds, plating wastewater, radioactive wastewater generated from nuclear power plants, geothermal power generation wastewater, flue gas desulfurization wastewater, and waste incineration plants. Smoke drainage and so on. These boron-containing water, which boron is included 1000~10000mg / l is subject to processing.
[0010]
These boron-containing waters may be subjected to the treatment of the present invention as they are, or the treatment of the present invention may be performed after the treatment for removing other components. When the raw water contains solids, other scale components, and corrosive components, these other components are preferably removed by pretreatment such as coagulation precipitation and filtration.
[0011]
The coagulation sedimentation treatment is an operation of adding a coagulant such as an aluminum salt or iron salt and, if necessary, an alkali agent such as calcium hydroxide and coagulating, and separating the solid and other coagulable components by solid-liquid separation. is there. Filtration includes general filtration for solids separation in addition to coagulation filtration.
[0012]
The pretreatment may be performed within the range that removes substances that hinder evaporation and concentration, such as solid matter removal. However, if all components other than boron are removed, boron will be purified in a later step. It can be recovered. In the pretreatment, boron may or may not be removed. Further, as a pretreatment, a concentration operation that reduces the load of the evaporation concentration process may be performed, but in the present invention , the concentration is performed in the evaporation concentration process without performing the RO membrane treatment . In addition to the RO membrane treatment , the concentration can be performed in the evaporative concentration step without performing the concentration operation with incomplete boron separation.
[0013]
In the evaporation and concentration step, the boron-containing water is evaporated together with the regenerated drainage of the ion exchange resin and concentrated to concentrate the boron compound. Although any evaporation apparatus such as heat evaporation, vacuum evaporation, or a combination thereof can be adopted for the evaporation concentration step, heat evaporation is preferable. As the type of each evaporator, any type of evaporator such as a flash type or a film type can be used.
[0014]
Boron-containing water, treated water such as pretreated water, and regenerated drainage of ion exchange resin are introduced into these evaporators to evaporate moisture, condense steam to generate condensed water. Evaporation and concentration can be efficiently performed with a small amount of heat by recovering heat using raw water as cooling water for condensation. Boron compounds and other non-volatile components are concentrated on the liquid side by the evaporation of moisture, and a concentrate is obtained.
[0015]
The concentration factor at this time is determined in consideration of the raw water concentration and the disposal method of the concentrate. The concentrate can be obtained in a solid or liquid state and can be recovered or disposed of as it is, and can also be disposed of after being cured with cement or the like. Further, it can be obtained in the form of a concentrated solution and post-treated by aggregation or the like. In any case, when the boron compound is obtained in a pure form, it can be recovered and used.
[0016]
Since the condensed water obtained in the evaporation and concentration step contains about 1 to 10 mg / l of boron that has been transferred along with the vapor, the condensed water is brought into contact with an ion exchange resin in the ion exchange step to thereby form boron. Remove. Since the boron contained in the condensed water is about 1/100 to 1 / 10,000 of the raw water, the amount of resin and regenerant used here should also be reduced at that rate compared to direct ion exchange of the raw water. Can do.
[0017]
The ion exchange resin used in the ion exchange step uses an anion exchange resin made of an N-methylglucamine type chelate resin to remove boron, but if it is necessary to remove cations, the cation exchange resin is also used. In this case, it is preferable to treat in a mixed bed.
[0018]
Anion exchange resins for removal of boron, a chelate resin having an increased adsorption amount of boron, the use of selective adsorption to N- methylglucamine type resins boron, in addition to removal rate of boron is high, The purity of the recovered boron compound (boric acid) is increased.
[0019]
In the ion exchange step, condensed water is passed through a resin layer filled with an ion exchange resin composed of an N-methylglucamine type chelate resin to perform ion exchange and exchange and adsorb boron. Most of the boron contained in the condensed water is orthoboric acid and is considered to be dissociated in the water according to the equation (1).
[Chemical 1]
H 3 BO 3 + H 2 O = B (OH) 4 + H + ... (1)
[0020]
The equilibrium in equation (1) varies with pH, and the higher the pH, the more the equilibrium tends to shift to the right. In this case, when the chelate resin is in the SO 4 form, the treatment is difficult unless the pH is 9 or more, and in the case of the OH form, the treatment can be performed even in the vicinity of neutrality. Therefore, it is preferable.
[0021]
In the ion exchange step, by bringing boron-containing water into contact with the chelate resin, the B (OH) 4 is exchanged and adsorbed on the resin and removed. From the treated water, boron and other anions are removed to obtain treated water with high purity close to pure water, which can be used as it is. When condensed water contains cations, cations can be removed by treatment with a cation exchange resin as described above, and when treating with a resin that also removes other anions as a chelate resin, Pure water can be obtained as treated water.
[0022]
When the chelate resin is saturated with boron, the process proceeds to a regeneration step, the resin layer is back-washed, and a regenerant is passed through to elute the exchanged and adsorbed boron. As the regenerant, general regenerators such as acids and alkalis can be used, but it is particularly preferable to use sulfuric acid, hydrochloric acid or nitric acid. Boron is eluted by passing the regenerant, and a regenerated drainage containing high concentration boron is generated. The resin after the elution of boron can be used for adsorption of boron again after being made into OH form with sodium hydroxide if necessary.
[0023]
The regenerated effluent is directly or after pH adjustment and mixed with raw water to return to the evaporation and concentration step. In the evaporative concentration step, orthoboric acid is more likely to move to the vapor side as the pH is lower. When the raw water is acidic or alkaline and the pH becomes neutral or higher by mixing the regenerated effluent, these may be simply mixed. When these are not mixed and become neutral or more, it is preferable to add an acid or an alkali as a pH adjuster. When acid and alkali are used as the regenerant, they are of course mixed and returned to the evaporation and concentration step.
[0024]
By evaporating and concentrating the water to be treated in which the regenerated effluent is mixed with the raw water in the evaporative concentration step, the concentrated boron and other substances contained in the regenerated effluent are concentrated and recovered or disposed of. Further, the concentration of boron to be treated increases due to the mixing of the regenerated effluent, and the amount of boron transferred to the condensed water side increases accordingly, but these are removed in the ion exchange step.
[0025]
Although it is preferable for the operation of the evaporative concentration process that the quality of the water to be treated supplied to the evaporative concentration process is as stable as possible, for this purpose, the regenerated effluent discharged intermittently is stored in a storage tank and evaporated. It is preferable to return to the concentration step by a certain amount. The evaporative concentration process continues to operate even during regeneration of the ion exchange resin, so the condensed water generated during that time can be stored to homogenize the processing volume, or multiple ion exchange devices can be installed to switch the process continuously. It is preferable to do it automatically.
[0026]
In the above treatment, since boron is concentrated in advance by evaporative concentration and only the condensed water with a low boron content is ion-exchanged, the amount of ion exchange resin and regenerant can be reduced, and the boron removal rate is increased to achieve high water quality. Treated water with a quality close to that of pure water can be obtained. In addition, since the regeneration drainage of the ion exchange resin is returned to the evaporation concentration step and concentrated by evaporation, the regeneration drainage can be easily treated and the amount of generated sludge is reduced.
[0027]
【The invention's effect】
According to the present invention, the boron-containing water containing 1000 to 10000 mg / l of boron is separated into condensed water and concentrate by evaporation and concentration without performing RO membrane treatment, and the condensed water is N -It includes an ion exchange step of removing boron by contacting with an ion exchange resin comprising a methylglucamine type chelate resin, and a regeneration step of regenerating the ion exchange resin with an acid and returning the regenerated effluent to the evaporation and concentration step. , to reduce the amount of ion exchange resin and a drug, regeneration effluent of the ion exchange resins without discharging, it is possible to boron is removed efficiently high removal rate obtain treated water of high quality, sludge The amount can also be reduced.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a system diagram showing a method for treating boron-containing water according to an embodiment of the present invention. In FIG. 1, 1 is an adjustment tank, 2 is an evaporative concentration apparatus, 3 is an ion exchange tank, and 4 is a drainage storage tank.
[0029]
The treatment method of boron-containing water by the above apparatus is as follows. First, the raw water is introduced into the adjustment tank 1 from the raw water channel 5, the regenerated drainage is introduced from the drainage supply channel 6, stirred and mixed by the stirrer 7, and a pH adjuster is injected from the drug injection channel 8 as necessary. Adjust the pH to neutral or higher. The mixed liquid in the adjustment tank 1 is introduced into the evaporative concentration apparatus 2 from the system path 9 as a liquid to be treated.
[0030]
The evaporative concentrator 2 is configured as a heat evaporation type, heats and evaporates the supplied liquid to be processed, condenses the generated vapor to obtain condensed water, and this condensed water is transferred from the system 10 to the ion exchange tank 3. On the other hand, the concentrate is taken out from the concentrate channel 11. Here, boron is concentrated on the concentrate side by evaporation, and a part of the boron moves to the condensate side. Although the steam is cooled by the liquid to be treated and recovered by heat, the detailed illustration is omitted.
[0031]
The ion exchange tank 3 has a resin layer 12 filled with an N-methylglucamine type chelate resin, and boron is exchanged and adsorbed by passing condensed water through the resin layer 12 in the ion exchange step. The treated water is taken out from the treated water channel 13. By providing a plurality of ion exchange tanks 3, continuous processing is performed by switching to the regeneration process when the ion exchange process is completed.
[0032]
The regenerant is injected from the chemical injection path 14 to regenerate the resin layer 12, and the regenerated drainage is sent from the system path 15 to the drainage storage tank 4. The regeneration efficiency can be increased by flowing an acid and an alkali sequentially as the regeneration agent. In this case, these effluents are collected in the effluent storage tank 4 and agitated by the stirrer 16 to neutralize the effluent, and supplied from the effluent supply path 6 to the adjustment tank 1 at a homogenized flow rate.
[0033]
[Example 1]
Examples of the present invention and comparative examples will be described below.
[0034]
Example 1
Raw water of pH 7.0 containing 2500 mg / l of boron was heated to 100 ° C. in an evaporating and concentrating apparatus and evaporated and concentrated at a concentration factor of 15 times to obtain condensed water having a boron concentration of 7.1 mg / l. When this condensed water was passed through a resin layer of N-methylglucamine type boron selective adsorption resin (Diaion CRB-02, trademark, manufactured by Mitsubishi Chemical Corporation) with SV2hr- 1 , treated water of boron 1 mg / l or less up to 440 BV. was gotten.
[0035]
When the resin layer was regenerated with 100 g / l sulfuric acid, a regenerated drainage solution having a boron concentration of 2450 mg / l was obtained. When this regenerated effluent was mixed with raw water without neutralization, it became pH 3, and when this was concentrated to a concentration factor of 15 in an evaporation concentrator, the boron concentration of the condensed water was 26 mg / l. When this condensed water was passed through the resin layer in the same manner as described above, treated water having a boron concentration of 1 mg / l or less was obtained up to 120 BV.
[0036]
Example 2
In Example 1, sodium hydroxide was added to the regenerated effluent to adjust the pH to 7.0, and the neutralized regenerated effluent was mixed at a ratio of 3 ml to 1 liter of raw water and concentrated by evaporation. The boron concentration of the condensed water at 15 times was 6.9 mg / l. When this condensed water was subjected to an ion exchange treatment in the same manner as in Example 1, treated water having a boron concentration of 1 mg / l or less was obtained up to BV440.
Moreover, the solid substance obtained by drying the concentrate in the said evaporation concentration process was 25g per liter of raw | natural water.
[0037]
Comparative Example 1
When the same waste water as in Example 1 was passed through a boron selective resin with SV2hr −1 , treated water of 1 mg / l or less was obtained up to 1.5 BV. Further, when the resin adsorbing boron was regenerated with 100 g / l sulfuric acid, a regenerated drainage containing 2480 mg / l of boron was obtained. In this case, the amount of the necessary resin was about 300 times that of Example 1, and the amount of the regenerant and the alkali agent for neutralizing the regenerated drainage was about 300 times that of the Example. For this reason, the amount of the regenerated drainage is almost the same as the amount of the raw water.
[0038]
Comparative Example 2
When the regenerated effluent obtained in Comparative Example 1 was stirred for 30 minutes after addition of sulfuric acid band 45 g / l and slaked lime 150 g / l (pH 12.4), treated water with a boron content of 180 mg / l was obtained. . The amount of solid matter generated at that time was 220 g / l-raw water. On the other hand, the solid matter produced in Example 2 is only 25 g / l-raw water, which is greatly reduced.
[Brief description of the drawings]
FIG. 1 is a system diagram showing a method for treating boron-containing water according to an embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Adjustment tank 2 Evaporation concentration apparatus 3 Ion exchange tank 4 Waste liquid storage tank 5 Raw water path 6 Waste liquid supply path 7, 16 Stirrer 8, 14 Chemical injection path 11 Concentrated liquid path 13 Process water path

Claims (2)

ホウ素が1000〜10000mg/l含まれているホウ素含有水を、RO膜処理を行うことなく、蒸発濃縮により凝縮水と濃縮物に分離する蒸発濃縮工程と、
凝縮水をN−メチルグルカミン型のキレート樹脂からなるイオン交換樹脂と接触させてホウ素を除去するイオン交換工程と、
イオン交換樹脂を酸で再生し、再生排液を蒸発濃縮工程に戻す再生工程と
を含むホウ素含有水の処理方法。
An evaporative concentration step in which boron-containing water containing 1000 to 10,000 mg / l of boron is separated into condensed water and concentrate by evaporative concentration without performing RO membrane treatment ;
An ion exchange step of contacting the condensed water with an ion exchange resin comprising an N-methylglucamine type chelate resin to remove boron;
A method for treating boron-containing water, comprising: a regeneration step of regenerating an ion exchange resin with an acid and returning the regenerated effluent to an evaporation concentration step.
再生排液を原水と混合し、中性以上のpHに調整して蒸発濃縮工程で蒸発濃縮する請求項1記載の方法。The method according to claim 1, wherein the regenerated effluent is mixed with raw water, adjusted to a neutral or higher pH, and evaporated and concentrated in an evaporation and concentration step.
JP33912297A 1997-12-09 1997-12-09 Method for treating boron-containing water Expired - Fee Related JP4058787B2 (en)

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JP4936505B2 (en) * 2005-10-04 2012-05-23 株式会社神鋼環境ソリューション Method and apparatus for treating ammonia-containing water
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Publication number Priority date Publication date Assignee Title
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