JPH0824911B2 - Wastewater treatment system containing hexavalent chromium - Google Patents
Wastewater treatment system containing hexavalent chromiumInfo
- Publication number
- JPH0824911B2 JPH0824911B2 JP36113692A JP36113692A JPH0824911B2 JP H0824911 B2 JPH0824911 B2 JP H0824911B2 JP 36113692 A JP36113692 A JP 36113692A JP 36113692 A JP36113692 A JP 36113692A JP H0824911 B2 JPH0824911 B2 JP H0824911B2
- Authority
- JP
- Japan
- Prior art keywords
- hexavalent chromium
- reducing agent
- wastewater
- concentration
- sulfurous acid
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Description
【０００１】[0001]
【産業上の利用分野】本発明は、めっき等で生じる６価
クロムを含有する廃水の処理システムに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waste water treatment system containing hexavalent chromium generated by plating or the like.
【０００２】[0002]
【従来の技術】クロムめっきはニッケルめっき上に光沢
仕上げとして、またクロム単独で工業用クロムめっきと
して表面硬化に用いられる非常に有用なめっき方法であ
る。そのめっき浴には３価クロムを用いるものと、６価
クロムを用いるものがあるが、経済性、めっき浴管理等
から工業的には６価クロムを用いているケースが圧倒的
に多い。一方、めっきプロセスから発する廃水の処理は
不可避であり、公害規制の強化が行われて以来めっき工
業にとっては廃水処理の高度化、安定化は重要な課題と
なっている。特に６価クロムは水質汚濁防止法により有
害物質に指定され、その無害化処理はめっき廃水処理の
中でも最も神経を使わねばならぬものである。前記めっ
き工程からの６価クロム含有廃水はクロムめっき後の水
洗水が主体であるが、その他にめっき前処理工程のアル
カリ洗浄工程において吊り手に浸透したクロム酸の溶出
によるものもあり、通常その濃度は数ｍｇ／ｌから数百
ｍｇ／ｌの範囲である。これらの排水処理方法として
は、（１）６価クロムを酸性亜硫酸ナトリウム（ＮａＨ
ＳＯ3 ）や硫酸第１鉄（ＦｅＳＯ4 ）のような還元剤に
より還元して無害な３価クロムにした後、水酸化クロム
として沈澱分離する方法、（２）イオン交換樹脂で吸着
除去する方法の２つが一般的に知られており、特に
（１）の方法が経済的に有利な場合が多いため広く用い
られている。また還元剤としては多量の汚泥を発生する
硫酸第１鉄よりも酸性亜硫酸ソーダーの方が好まれて使
用されている。（１）の方法で従来行われて来た処理シ
ステムは、先ず６価クロム廃水のＰＨを２．０〜３．０
程度に下げ、次に酸性亜硫酸ソーダー等の還元剤を、酸
化還元電位（ＯＲＰ）を測定しながら投入し、その電位
がある値Ｐ0 に収斂するように還元剤の添加量を調節す
る。６価クロム含有廃水の酸化還元電位は図２のように
なっており、電位が或る値Ｐ0 より低ければ６価クロム
は還元された状態である。ここで、酸化還元電位計を用
いた従来の処理方式のフロー図を図４に示すが、先ずめ
っき工程などで生じる６価クロムを含有する廃水を原水
貯槽７０に溜めてポンプ７１によりＰＨ調整槽７２に送
り適当量の硫酸を投入してＰＨ２．０〜３．０程度に調
整し、これを次の還元槽７３において酸性亜硫酸ソーダ
ー等からなる還元剤を用いて６価クロムを３価クロムに
還元処理する。ここで、前記還元槽７３には酸化還元電
位計（ＯＲＰ計）７４を備え、処理液の酸化還元電位
（ＯＲＰ）を測定し、その電位が或る値Ｐ0 に収斂する
ように、前記還元剤の添加量を調節する。この廃水を更
に中和槽７５に送り、適当量のカセイソーダーを入れて
中和し、そのオーバーフロー分を中間槽７６に取りポン
プ７７で汲み上げて、凝集沈降槽７８に入れ、適当量の
凝集剤を投入して水酸化クロムとして沈澱させ回収して
いた。2. Description of the Related Art Chromium plating is a very useful plating method which is used for surface hardening as a bright finish on nickel plating and as an industrial chrome plating with chrome alone. There are two types of plating baths that use trivalent chromium and those that use hexavalent chromium. However, in terms of economy, plating bath management, etc., industrially, hexavalent chromium is predominantly used in many cases. On the other hand, the treatment of wastewater generated from the plating process is unavoidable, and since the pollution control has been strengthened, the sophistication and stabilization of wastewater treatment have been an important issue for the plating industry. In particular, hexavalent chromium is designated as a harmful substance by the Water Pollution Control Law, and its detoxification treatment is the most nerve-consuming process in the plating wastewater treatment. The hexavalent chromium-containing wastewater from the plating step is mainly rinse water after chromium plating, but there is also some that is due to the elution of chromic acid that has penetrated into the handle in the alkaline cleaning step of the plating pretreatment step, The concentration ranges from a few mg / l to a few hundred mg / l. These wastewater treatment methods include (1) adding hexavalent chromium to acidic sodium sulfite (NaH
SO 3 ) or ferrous sulfate (FeSO 4 ) to reduce harmless trivalent chromium and then precipitate and separate as chromium hydroxide, (2) adsorption and removal with ion exchange resin 2 are generally known, and in particular, the method (1) is widely used because it is often economically advantageous. Further, as a reducing agent, acid sodium sulfite is more preferred and used than ferrous sulfate which generates a large amount of sludge. In the treatment system that has been conventionally performed by the method (1), first, the pH of hexavalent chromium wastewater is adjusted to 2.0 to 3.0.
Then, a reducing agent such as acidic sodium sulfite is added while measuring the redox potential (ORP), and the addition amount of the reducing agent is adjusted so that the potential converges to a certain value P 0 . The redox potential of hexavalent chromium-containing wastewater is as shown in FIG. 2, and if the potential is lower than a certain value P 0 , hexavalent chromium is in a reduced state. Here, a flow chart of a conventional treatment method using an oxidation-reduction potentiometer is shown in FIG. 4. First, waste water containing hexavalent chromium generated in a plating process or the like is stored in a raw water storage tank 70 and a pH adjusting tank is pumped by a pump 71. It is sent to 72 and a proper amount of sulfuric acid is added to adjust the pH to about 2.0 to 3.0, and hexavalent chromium is converted to trivalent chromium in the next reducing tank 73 using a reducing agent such as acidic sodium sulfite. Perform reduction processing. Here, the reduction tank 73 is provided with an oxidation-reduction potentiometer (ORP meter) 74, measures the oxidation-reduction potential (ORP) of the treatment liquid, and reduces the reduction so that the potential converges to a certain value P 0. Adjust the amount of agent added. This wastewater is further sent to the neutralization tank 75, and an appropriate amount of caustic soda is added to neutralize it. The overflowed amount is taken into the intermediate tank 76 and pumped up by the pump 77 into the coagulation sedimentation tank 78, where an appropriate amount of coagulant is added. Was charged and precipitated as chromium hydroxide to be recovered.
【０００３】[0003]
【発明が解決しようとする課題】図４に示す前記従来の
処理システムにおいては、酸化還元電位が正しく計測で
きることが安定操業の必須条件である。しかし、廃水中
にはごく微量の油分をはじめ、酸化還元電位計の電極を
不活性にする物質が含まれ、酸化還元電位計の感度が低
下し正しい電位が計測できない。即ち、酸化還元電位
は、前記処理システムにおいては、通常、低い値を示す
ため還元剤の供給が不足して還元不良を起こすことにな
り、これは、有害物質である６価クロムの流失という、
起こってはならない事態を招くことになる。そこで、前
記事態を防ぐためには電極の汚染を防止する必要があ
り、この為、数時間に一度の電極洗浄、場合によっては
電極内部の汚染部を削り取る等の処置が必要とされてい
た。更に、図２に示す廃水の酸化還元電位によって表さ
れる酸化還元電位曲線の変曲点が廃水の組成状態によっ
て変化するため、廃水の組成状態が異なれば、一律に特
定の酸化還元電位値によって前記還元剤の投入量を制御
できないという問題点もあった。これは廃水中に含まれ
る２価の鉄、ＰＨの変動などによるものと考えられる。
即ち、図３に示すように通常の廃水では酸化還元電位は
（ａ）の曲線を描くが、廃水の組成の変化により酸化還
元電位の曲線が（ｂ）の傾向に変化すれば通常より高い
電位で還元が完了することとなり、還元剤添加の制御を
通常の電位で行えば還元剤の過剰投入となり、逆に酸化
還元電位の曲線が（ｃ）の傾向に変化すれば還元剤の投
入不足となる。還元不良は当然許されるべきものではな
いが、還元剤の過剰供給は凝集沈澱効果を阻害し浮遊粒
子状物質の流失というこれまた許されない事態を招く。
本発明はかかる事情に鑑みてなされたもので、正確に還
元剤の投入を制御できる６価クロム含有廃水の還元処理
システムを提供することを目的とする。In the conventional processing system shown in FIG. 4, it is an essential condition for stable operation that the redox potential can be measured correctly. However, the wastewater contains a very small amount of oil and a substance that inactivates the electrodes of the redox electrometer, and the sensitivity of the redox electrometer decreases, so that the correct potential cannot be measured. That is, in the above-mentioned treatment system, the oxidation-reduction potential usually shows a low value, so that the supply of the reducing agent is insufficient and reduction failure occurs, which is the loss of hexavalent chromium which is a harmful substance.
It will lead to things that should not happen. Therefore, in order to prevent the above situation, it is necessary to prevent the electrode from being contaminated. Therefore, it is necessary to wash the electrode once every several hours, and in some cases, to remove the contaminated portion inside the electrode. Further, since the inflection point of the redox potential curve represented by the redox potential of the wastewater shown in FIG. 2 changes depending on the composition state of the wastewater, if the composition state of the wastewater differs, it will be uniformly changed by a specific redox potential value. There is also a problem that the amount of the reducing agent added cannot be controlled. It is considered that this is due to changes in divalent iron and PH contained in the wastewater.
That is, as shown in FIG. 3, in normal wastewater, the redox potential draws the curve of (a), but if the curve of the redox potential changes to the tendency of (b) due to the change of the composition of the wastewater, the potential is higher than usual. Thus, the reduction is completed, and if the control of addition of the reducing agent is carried out at a normal potential, the reducing agent is excessively charged. Conversely, if the curve of the oxidation-reduction potential changes to the tendency of (c), the reducing agent is insufficiently charged. Become. Poor reduction should not be tolerated, but an excessive supply of a reducing agent hinders the flocculation-precipitation effect, resulting in the loss of suspended particulate matter, which is another unacceptable situation.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a reduction treatment system for hexavalent chromium-containing wastewater capable of accurately controlling the input of a reducing agent.
【０００４】[0004]
【課題を解決するための手段】前記目的に沿う請求項１
記載の６価クロム含有廃水の処理システムは、６価クロ
ムの含有廃水に亜硫酸系還元剤を加えて還元処理する６
価クロム含有廃水の還元システムにおいて、処理中に発
生する亜硫酸ガスの濃度及び／又はその濃度変化率によ
り、前記亜硫酸系還元剤の投入量を制御するようにして
構成されている。また、請求項２記載の６価クロム含有
廃水の処理システムは、請求項１記載の処理システムに
おいて、亜硫酸ガスの濃度及び／又はその濃度変化率
は、連続亜硫酸ガス分析計によって行うようにして構成
されている。A method according to the above-mentioned object.
The hexavalent chromium-containing wastewater treatment system described is a reduction treatment by adding a sulfite reducing agent to the hexavalent chromium-containing wastewater.
In a reduction system of waste water containing chromium (VI), the amount of the sulfite reducing agent added is controlled by the concentration of sulfurous acid gas generated during the treatment and / or the rate of change of the concentration. Further, the treatment system for hexavalent chromium-containing waste water according to claim 2 is configured such that, in the treatment system according to claim 1, the concentration of sulfurous acid gas and / or the rate of change in concentration thereof are measured by a continuous sulfurous acid gas analyzer. Has been done.
【０００５】[0005]
【作用】請求項１及び２記載の６価クロム含有廃水の処
理システムは、６価クロムの含有廃水に亜硫酸系還元剤
を加えて還元処理する場合に発生する亜硫酸ガスを捕集
し、例えば、亜硫酸ガス検出計あるいは連続亜硫酸ガス
分析計にて測定して、該亜硫酸ガスの濃度値及び／又は
その濃度変化率により、前記亜硫酸系還元剤の投入量を
制御するようにしている。即ち、還元剤に亜硫酸系還元
剤を用いているので、６価クロムが完全に還元された場
合には、前記亜硫酸系還元剤の一部に余剰の亜硫酸イオ
ンが残り、これが、低ＰＨの下では水素イオンと反応し
て亜硫酸ガスとなって気泡化するが、６価クロムが完全
に還元されない場合には、強い酸化力をもつ６価クロム
と前記亜硫酸イオンとが反応するので、亜硫酸ガスは一
切発生しない。従って、発生する亜硫酸ガスの濃度を測
定することによって、６価クロムの完全な還元状況を判
断できることとなり、かつ、亜硫酸ガス濃度の測定は、
例えば連続亜硫酸ガス分析計を用いて長時間の正確な連
続測定が行えるので、従来法の如く、溶液に電極を浸漬
することによって発生する電極汚染によって測定精度が
悪くなるということもない。The treatment system for wastewater containing hexavalent chromium according to claims 1 and 2 collects sulfurous acid gas generated when the wastewater containing hexavalent chromium is subjected to reduction treatment by adding a sulfite reducing agent. The amount of the sulfurous acid-based reducing agent added is controlled by the concentration value of the sulfurous acid gas and / or the rate of change in the concentration, which is measured by a sulfurous acid gas detector or a continuous sulfurous acid gas analyzer. That is, since the sulfite-based reducing agent is used as the reducing agent, when the hexavalent chromium is completely reduced, an excess of sulfite ion remains in a part of the sulfite-based reducing agent, which is under low pH. Then, it reacts with hydrogen ions to form sulfurous acid gas and bubbles, but when hexavalent chromium is not completely reduced, hexavalent chromium having a strong oxidizing power reacts with the sulfite ion. It does not occur at all. Therefore, by measuring the concentration of the generated sulfurous acid gas, it is possible to judge the complete reduction state of hexavalent chromium, and the measurement of the sulfurous acid gas concentration is
For example, since accurate continuous measurement can be performed for a long time using a continuous sulfur dioxide analyzer, the measurement accuracy does not deteriorate due to electrode contamination generated by immersing the electrode in the solution as in the conventional method.
【０００６】[0006]
【実施例】続いて、添付した図面を参照しつつ、本発明
を具体化した実施例について説明し、本発明の理解に供
する。図１は本発明の一実施例に係る連続亜硫酸ガス分
析計を用いた６価クロム含有排水の処理システムの説明
図である。原廃水を先ずＰＨ調整槽１０において硫酸に
てＰＨ２．０〜３．０に調整し還元槽１１に送る。還元
槽１１には亜硫酸系還元剤の一例である酸性亜硫酸ナト
リウムが供給され、６価クロムから３価クロムへの還元
が行われる。この場合還元が終了した後は、余剰の亜硫
酸水素ナトリウムは、ＰＨ２〜３のもとでは水素イオン
と次式のように反応し亜硫酸ガスが発生する。 ＨＳＯ3 - ＋ Ｈ+ → Ｈ2 Ｏ ＋ ＳＯ2 次に還元槽１１より廃水をサンプリングしポンプ１２に
よりサンプル採取管１３により気液分離箱１４へ導く。
このサンプル中の気液分離した亜硫酸ガスは外気導入口
１６からの空気によって一定の倍率で希釈され、連続亜
硫酸ガス分析計１７に導かれる。気液分離箱１４からの
排水は還元槽１１に戻す。赤外線を利用して吸光度から
亜硫酸ガスの濃度を測定する連続亜硫酸ガス分析計１７
によって、導入された気体の亜硫酸ガスを連続分析し、
その信号電圧を還元剤供給ポンプ１８の制御盤１９に送
る。制御盤１９により亜硫酸ガス濃度が或る濃度Ｃ0 以
下になると、還元剤供給ポンプ１８が始動し、亜硫酸ガ
ス濃度がＣ0 以上になった時点で還元剤供給ポンプ１８
が停止するよう制御する。そして、廃水はさらに図示さ
れていない中和槽、凝集沈降槽に送られクロムは水酸化
クロムとして沈降させ、回収される。Embodiments of the present invention will now be described with reference to the accompanying drawings to provide an understanding of the present invention. FIG. 1 is an explanatory diagram of a treatment system for wastewater containing hexavalent chromium using a continuous sulfur dioxide gas analyzer according to an embodiment of the present invention. First, the raw wastewater is adjusted to pH 2.0 to 3.0 with sulfuric acid in the pH adjusting tank 10 and sent to the reducing tank 11. An acidic sodium sulfite, which is an example of a sulfite-based reducing agent, is supplied to the reducing tank 11 to reduce hexavalent chromium to trivalent chromium. In this case, after the reduction is completed, excess sodium hydrogen sulfite reacts with hydrogen ions under PH2 to PH3 as shown in the following equation to generate sulfurous acid gas. HSO 3 − + H + → H 2 O + SO 2 Next, the waste water is sampled from the reducing tank 11 and guided to the gas-liquid separation box 14 by the pump 12 through the sampling pipe 13.
The gas-liquid separated sulfurous acid gas in this sample is diluted with air from the outside air inlet 16 at a constant ratio, and then introduced into the continuous sulfur dioxide analyzer 17. The waste water from the gas-liquid separation box 14 is returned to the reduction tank 11. Continuous Sulfurous Acid Gas Analyzer 17 for measuring the concentration of sulfurous acid gas from the absorbance using infrared rays
Continuously analyzes the introduced gaseous sulfurous acid gas,
The signal voltage is sent to the control panel 19 of the reducing agent supply pump 18. When the sulfur dioxide gas concentration becomes a certain concentration C 0 or less by the control panel 19, the reducing agent supply pump 18 is started, and when the sulfur dioxide gas concentration becomes C 0 or more, the reducing agent supply pump 18
Control to stop. Then, the wastewater is further sent to a neutralization tank and a coagulation sedimentation tank, which are not shown, and chromium is precipitated as chromium hydroxide and recovered.
【０００７】さらに、実際の操業では操業中にも廃水中
の６価クロム濃度の変動が相当程度あるので、安定作働
するためには制御盤１９に次のような制御機能を付加す
るのが好ましい。即ち、通常６価クロムが低濃度の廃水
を処理している場合は還元剤の過剰供給を防ぐため還元
剤の供給速度は遅くし、６価クロムが高濃度の廃水に切
り替わった場合には還元剤の供給速度を早くする。この
ため、亜硫酸ガス濃度値を微分し、濃度低下、又は上昇
の速度に合わせて還元剤の供給速度を増大または減少さ
せる制御回路を組み込むようにするのが好ましい。な
お、前記実施例においては、亜硫酸ガスの検出に赤外線
を利用して吸光度から亜硫酸ガスの連続分析してその濃
度を測定したが、亜硫酸ガスの濃度の測定には、昭和６
２年６月２５日に発行の通商産業省立地公害局監修の
「公害防止の技術と法規」に一例が記載されているよう
に、紫外線吸収法、溶液導電率法、炎光光度検出法、定
電圧電解法あるいは電量法を応用した亜硫酸ガスの濃度
検出方法であっても本発明は適用される。Further, in actual operation, the hexavalent chromium concentration in the wastewater varies considerably during operation. Therefore, the following control functions should be added to the control panel 19 for stable operation. preferable. That is, when the hexavalent chromium is normally treated with low-concentration wastewater, the supply rate of the reducing agent is slowed to prevent excessive supply of the reducing agent, and when the hexavalent chromium is switched to the high-concentration wastewater, reduction is performed. Increase the supply rate of the agent. Therefore, it is preferable to incorporate a control circuit that differentiates the sulfur dioxide gas concentration value and increases or decreases the reducing agent supply rate according to the rate of concentration decrease or increase. In the above examples, infrared rays were used to detect the sulfurous acid gas, and the concentration of the sulfurous acid gas was measured by continuous analysis from the absorbance.
As described in "Techniques and Regulations for Pollution Prevention" supervised by the Ministry of International Trade and Industry's Location Pollution Bureau, issued on June 25, 2nd, the ultraviolet absorption method, solution conductivity method, flame photometric method, The present invention can be applied even to a method for detecting the concentration of sulfurous acid gas by applying the constant voltage electrolysis method or the coulometry method.
【０００８】[0008]
【発明の効果】請求項１及び２記載の６価クロム含有廃
水の処理システムにおいては、還元剤の投与の過剰、不
足を、連続亜硫酸ガス分析計を用いて発生する亜硫酸ガ
スの濃度を測定することによって判断しているため、６
価クロムの完全な還元状況が判断でき、かつ亜硫酸ガス
濃度の測定は長時間の正確な連続測定が行えるので、従
来法の如く、溶液に電極を浸漬することによって発生す
る電極汚染によって測定精度が悪くなるということもな
いし、数時間に一度の電極洗浄、電極内部の汚染部を削
り取る等の処置も不必要となる。さらに、酸化還元電位
計を用いた従来の処理方式では避けられない廃水の組成
の変化による６価クロムの還元不足、還元剤の過剰投与
による浮遊粒子状物質の流失という許されない事態をさ
けることができるようになった。特に、請求項２記載の
６価クロム含有廃水の処理システムにおいては、還元剤
の投与の過剰、不足を連続亜硫酸ガス分析計を用いて発
生する亜硫酸ガスの濃度及び／又はその濃度変化率を測
定することによって判断しているため、ＰＨの安定とい
う条件さえみたせば、亜硫酸ガスの発生を常に生じさせ
ながら、そのレベルを十分に低い値に制御することによ
り、還元剤の添加を必要最小限にかつ、安定して行うこ
とができる。In the treatment system for hexavalent chromium-containing wastewater according to the first and second aspects, the concentration of the sulfurous acid gas generated is measured by using a continuous sulfurous acid gas analyzer to determine whether the dosing of the reducing agent is excessive or insufficient. 6 because it is judged by
Since the complete reduction state of valent chromium can be determined and the sulfurous acid gas concentration can be measured continuously for a long time, the measurement accuracy is improved by the electrode contamination generated by immersing the electrode in the solution as in the conventional method. It does not become worse, and it is not necessary to wash the electrode once every several hours or scrape off the contaminated portion inside the electrode. Furthermore, it is possible to avoid the unacceptable situation of insufficient reduction of hexavalent chromium due to changes in the composition of wastewater that cannot be avoided by the conventional treatment method using an oxidation-reduction potentiometer, and loss of suspended particulate matter due to excessive administration of a reducing agent. I can do it now. Particularly, in the treatment system for hexavalent chromium-containing wastewater according to claim 2, the concentration of sulfurous acid gas and / or the rate of change of concentration thereof generated by measuring the excess or insufficiency of the reducing agent using a continuous sulfite gas analyzer are measured. As long as the conditions for stable PH are met, the sulfur dioxide gas is always generated, and the level is controlled to a sufficiently low value to minimize the addition of reducing agent. In addition, it can be performed stably.
【図１】図１は本発明の一実施例に係る亜硫酸ガス自動
分析計を用いた６価クロム含有排水の処理システムの説
明図である。FIG. 1 is an explanatory view of a treatment system for wastewater containing hexavalent chromium using an automatic sulfur dioxide gas analyzer according to an embodiment of the present invention.
【図２】廃水の酸化還元電位によって表される酸化還元
の境界電位曲線を表す図である。FIG. 2 is a diagram showing a redox boundary potential curve represented by a redox potential of waste water.
【図３】通常の廃水における酸化還元の境界電位曲線を
表す図である。FIG. 3 is a diagram showing a boundary potential curve of redox in normal wastewater.
【図４】従来例に係る酸化還元電位計を用いた６価クロ
ム含有廃水の処理システムのフロー図である。FIG. 4 is a flow diagram of a hexavalent chromium-containing wastewater treatment system using a redox potentiometer according to a conventional example.
１０ ＰＨ調整槽 １１ 還元槽 １２ ポンプ １３ サンプル採取管 １４ 気液分離箱 １５ 廃水管 １６ 外気導入口 １７ 連続亜硫酸ガス分析計 １８ 還元剤供給ポンプ １９ 制御盤 ２０ 還元剤タンク ２１ 酸性亜硫酸ナトリウム 10 PH adjustment tank 11 Reduction tank 12 Pump 13 Sample collection pipe 14 Gas-liquid separation box 15 Waste water pipe 16 Outside air inlet 17 Continuous sulfite gas analyzer 18 Reducing agent supply pump 19 Control panel 20 Reducing agent tank 21 Sodium acid sulfite
Claims (2)
を加えて還元処理する６価クロム含有廃水の還元システ
ムにおいて、 処理中に発生する亜硫酸ガスの濃度及び／又はその濃度
変化率により、前記亜硫酸系還元剤の投入量を制御する
ことを特徴とする６価クロム含有廃水の処理システム。1. A reduction system for a hexavalent chromium-containing wastewater, which comprises adding a sulfite-based reducing agent to wastewater containing hexavalent chromium, to reduce the concentration of sulfurous acid gas generated during the treatment and / or the rate of change of the concentration. A treatment system for hexavalent chromium-containing wastewater, characterized in that the amount of the sulfite reducing agent added is controlled.
化率は、連続亜硫酸ガス分析計によって行う請求項１記
載の６価クロム含有廃水の処理システム。2. The treatment system for hexavalent chromium-containing wastewater according to claim 1, wherein the concentration of sulfurous acid gas and / or the rate of change in the concentration thereof are measured by a continuous sulfurous acid gas analyzer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP36113692A JPH0824911B2 (en) | 1992-03-24 | 1992-12-29 | Wastewater treatment system containing hexavalent chromium |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4-98945 | 1992-03-24 | ||
| JP9894592 | 1992-03-24 | ||
| JP36113692A JPH0824911B2 (en) | 1992-03-24 | 1992-12-29 | Wastewater treatment system containing hexavalent chromium |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0679289A JPH0679289A (en) | 1994-03-22 |
| JPH0824911B2 true JPH0824911B2 (en) | 1996-03-13 |
Family
ID=26440034
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP36113692A Expired - Lifetime JPH0824911B2 (en) | 1992-03-24 | 1992-12-29 | Wastewater treatment system containing hexavalent chromium |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0824911B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108586766A (en) * | 2018-05-09 | 2018-09-28 | 中钢集团洛阳耐火材料研究院有限公司 | A kind of method of multiple tooth coordination polymer of the liquid phase method synthesis containing chromium |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7264733B2 (en) | 2001-09-03 | 2007-09-04 | Aquatech Corporation | Method for treating heavy-metal-containing wastewater using sulfidizing agent |
| JP4840229B2 (en) * | 2007-03-02 | 2011-12-21 | 株式会社吉崎メッキ化工所 | Method and apparatus for maintaining appropriate concentration of reducing agent in waste water after reduction treatment of waste water containing hexavalent chromium |
| CN104310651B (en) * | 2014-10-28 | 2016-09-14 | 温玉友 | Oil-containing stainless-steel cold-rolling wastewater treatment equipment and processing method |
| CN104310650B (en) * | 2014-10-28 | 2016-09-14 | 温玉友 | Chromium stainless steel cold rolling wastewater processing method |
-
1992
- 1992-12-29 JP JP36113692A patent/JPH0824911B2/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108586766A (en) * | 2018-05-09 | 2018-09-28 | 中钢集团洛阳耐火材料研究院有限公司 | A kind of method of multiple tooth coordination polymer of the liquid phase method synthesis containing chromium |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0679289A (en) | 1994-03-22 |
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