JPS5925635B2 - How to treat wastewater - Google Patents
How to treat wastewaterInfo
- Publication number
- JPS5925635B2 JPS5925635B2 JP54041057A JP4105779A JPS5925635B2 JP S5925635 B2 JPS5925635 B2 JP S5925635B2 JP 54041057 A JP54041057 A JP 54041057A JP 4105779 A JP4105779 A JP 4105779A JP S5925635 B2 JPS5925635 B2 JP S5925635B2
- Authority
- JP
- Japan
- Prior art keywords
- amount
- potential
- hydrogen peroxide
- change
- wastewater
- 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
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- Treatment Of Water By Oxidation Or Reduction (AREA)
Description
【発明の詳細な説明】
この発明は、工場排水COD値を高める原因になつてい
る排水中の亜硝酸塩を無害な硝酸塩にするため、過酸化
水素(H202)を排水中に添加混合せしめ、酸化処理
する際の完全処理法とその自動化に関する。Detailed Description of the Invention The present invention involves adding and mixing hydrogen peroxide (H202) to wastewater to reduce nitrite in wastewater, which is a cause of increasing the COD value of industrial wastewater, and convert it into harmless nitrate. Regarding the complete processing method and its automation.
一般に、亜硝酸塩を含む熔融塩は加熱媒体として広く使
用されており、該加熱媒体で加熱処理された被処理物に
は亜硝酸塩の熔融塩が付着しているため、この塩を水洗
して取除く必要がある。Generally, molten salt containing nitrite is widely used as a heating medium, and since the molten salt of nitrite adheres to the workpiece that has been heat-treated with the heating medium, this salt can be removed by washing with water. need to be removed.
従つてこの水洗後の排水は亜硝酸塩が含まれCOD値が
高くなり公害発生のおそれがある。かゝる排水をH2O
2で酸化処理して無害な硝酸塩にして排出する方法は、
既に特開昭53−28952号で知られているところで
ある。然るに従来のこの方法は、H2O2の連続添加に
よつて変化する排水の酸化還元電位(ORP)を測定し
、処理反応終点での0RPの変化を0RP計器の目視管
理のもとにとらえて、その時点でH2O2投入用のポン
プ作動によつてその投入を中止する等、すべて此等の作
業は人手によつて行われていた。即ち、上記のH2O2
連続投人添加による0RPの時間に伴う変化を図示すれ
ば第1図の如し、図によれば槽内の排水全体に添加した
H2O2が均一に攪拌される迄に時間を要する為に0R
Pを表す1は絶えず上下に振動しながら上昇し、下降点
2で下降し初め、この点が処理反応終点であるが、目視
によつてこの下降点2の電位を正確にとらえる事は困難
である。それは下降点2の直前でも電位が上下に振動し
ているため下降点2と同電位を示す事があるからである
。従つて処理反応終点の目視判定には常に時間的おくれ
を生じ、たとえ熟練した作業者と錐もH2O2は連続投
入の為にH2O2は過量に添加することXなり、二次公
害発生のおそれがあつた。又作業者の代りに電位の自動
計測による自動制御によつてもH2O2の過剰投入が起
る事は同じである。それはH2O2連続投入のために0
RPの値は図中1の如く絶えず上下に振動するので下降
点2を正確にとらえること自体が目視であろうが自動計
測であろうが全く同様に困難であるからである。この発
明は、叙上の点に鑑みてなされたもので、排水中の亜硝
酸塩をH2O2で酸化処理する排水の処理方法において
、H2O2を連続的に投入せず、間欠的に排水中に投入
し、各投入後電位の振動が消失し安定した時点における
0RPを測定し、この安定電位と前回投入後の安定電位
との電位変化が逆転(例えば増加から減少すること)し
た時点でH2O2投入を中止することによつて、排水の
完全処理とその無人運転化を可能にしたものである。即
ち、この発明は、H2O2投入を連続的でなく間欠的に
換言すればH2O2を少量づつ分割して投入する事及び
各投入後H2O2が均一に攪拌されて0RPの振動が消
えた時点での安定電位を測定する事によつて酸化処理中
の正確な電位をとらえる事ができるので電位の自動計測
によるH2O2投入の自動制御を可能にしたものである
。つまり、H2O2の各投入後の正確な電位が測定でき
るので前回投入後の電位と比較して電位変化が逆転した
時点が酸化処理反応終点である事が判る。従つてこれに
より目視測定は勿論であるが0RPの自動計測も可能と
なり、その結果H2O2投入の自動制御が可能となる。
この発明ではH2O2の1回の投入量としては、完全に
亜硝酸塩の酸化が完結した時点で、更に過剰のH2O2
が最后の回で投入されても処理済の排水量全体中に含ま
れるその過剰H2O2によるCOD値が目標値例えば1
0ppm以下になるような量のH2O2を1回の投入量
とすればよい。Therefore, the waste water after washing contains nitrites and has a high COD value, which may cause pollution. The waste water is converted into H2O.
The method in step 2 is to oxidize it and turn it into harmless nitrate and discharge it.
This is already known from Japanese Patent Application Laid-Open No. 53-28952. However, this conventional method measures the oxidation-reduction potential (ORP) of wastewater, which changes due to continuous addition of H2O2, and detects the change in ORP at the end point of the treatment reaction under visual control using an ORP meter. At that time, all such work was done manually, such as stopping the injection of H2O2 by operating the pump. That is, the above H2O2
Figure 1 shows the change in 0RP due to continuous addition of water over time.As shown in the figure, 0R changes over time because it takes time for the H2O2 added to the entire wastewater in the tank to be uniformly stirred.
1, which represents P, rises while constantly vibrating up and down, and begins to fall at the falling point 2, which is the end point of the processing reaction, but it is difficult to accurately capture the potential at this falling point 2 by visual inspection. be. This is because the potential oscillates up and down even just before the falling point 2, so it may show the same potential as the falling point 2. Therefore, there is always a time lag in the visual judgment of the end point of the treatment reaction, and even with skilled workers and drillers, since H2O2 is continuously added, an excessive amount of H2O2 may be added, and there is a risk of secondary pollution occurring. Ta. Excessive injection of H2O2 also occurs when automatic control is performed by automatically measuring the potential instead of the operator. It is 0 due to continuous H2O2 input.
This is because the value of RP constantly oscillates up and down as shown in 1 in the figure, so it is equally difficult to accurately determine the point of descent 2, whether by visual observation or automatic measurement. This invention was made in view of the above points, and in a wastewater treatment method in which nitrites in wastewater are oxidized with H2O2, H2O2 is not continuously introduced into the wastewater, but is intermittently introduced into the wastewater. After each injection, measure 0RP at the time when the potential oscillation disappears and becomes stable, and stop adding H2O2 when the potential change between this stable potential and the stable potential after the previous injection is reversed (for example, from increasing to decreasing). By doing so, it has become possible to completely treat wastewater and operate it unmanned. In other words, this invention allows H2O2 to be added intermittently rather than continuously, in other words, H2O2 is added in small portions, and after each injection, H2O2 is stirred uniformly and stabilized when the 0RP vibration disappears. By measuring the potential, it is possible to obtain an accurate potential during the oxidation treatment, so automatic control of H2O2 injection is possible by automatically measuring the potential. In other words, since the accurate potential after each injection of H2O2 can be measured, it can be determined that the end point of the oxidation treatment reaction is the point at which the potential change is reversed compared to the potential after the previous injection. Therefore, this allows not only visual measurement but also automatic measurement of 0RP, and as a result, automatic control of H2O2 injection becomes possible.
In this invention, as for the amount of H2O2 added at one time, when the oxidation of nitrite is completely completed, an additional amount of excess H2O2 is added.
Even if H2O2 is added at the last time, the COD value due to the excess H2O2 contained in the total amount of treated wastewater will be lower than the target value, for example 1.
The amount of H2O2 added at one time may be such that the amount is 0 ppm or less.
例えば5m3の排水に対しては35%H2O2を1回の
投入量として200CC投入すれば酸化反応が完結した
時点で更に200CC過剰投入されてもCOD値は約1
0ppmとなるだけである。又排水中の亜硝酸塩の濃度
が余り変動しない場合には間欠投入の初期には比較的多
量のH2O2を投入し後期に少量のH2O2を投入する
方法でもよい。この発明による酸化処理反応終点即ち0
RPの変化が逆転した時点の検出法を詳述すれば次の如
し。For example, for 5 m3 of waste water, if 200 cc of 35% H2O2 is added at one time, the COD value will be approximately 1 even if an additional 200 cc is added when the oxidation reaction is completed.
It only becomes 0 ppm. Alternatively, if the concentration of nitrite in the wastewater does not change much, a relatively large amount of H2O2 may be added at the beginning of the intermittent injection, and a small amount of H2O2 may be added at the later stage. The end point of the oxidation treatment reaction according to this invention, that is, 0
The method for detecting when the change in RP is reversed is as follows.
第2図は、この発明による方法で亜硝酸塩を含む一定量
の排水中に少量づつH2O2を間欠的に投人した時の0
RPの時間に伴う変化を示した図表である。図によれば
、H2O2をA,B,C,D,E、時に間欠的に投人す
る事によつて0RPは各投入毎に最初は1の如く上下に
振動を生じるが順次3の如く振動がとまり安定化するの
で、この様に安定したA,b,c,d,e、時の0RP
の測定値はH2O2の各投入後の正確な0RPを与える
事になる。従つて常に前回投入後の電位と今回投入後の
電位とを比較する事によつて、即ちaとb、bとC.c
とD,.dとe時の電位を比較する事によつてその変化
が逆転した時点即ちe測定時を知る事ができ、これが酸
化処理反応終点2である。尚H2O2の各投入後電位の
振動が消える迄に要する時間は、亜硝酸塩を含む排水量
、攪拌条件等によつてきまるものであるが、予め実験的
にその所要時間は容易に判るのでその所要時間毎に0R
Pを測定する様にすればよい。勿論検知器によつて電位
の振動の消失時をしる事もできる。次に、この発明によ
り酸化処理反応終点検出とH2O2投入を自動制御した
場合の実施例に就て詳述する。Figure 2 shows the 0.0 0.00% when H2O2 is intermittently poured in small amounts into a fixed amount of wastewater containing nitrite using the method according to the present invention.
It is a chart showing changes in RP over time. According to the diagram, by intermittently pouring H2O2 into A, B, C, D, and E, 0RP initially vibrates up and down like 1 with each injection, but then vibrates sequentially like 3. stops and becomes stable, so the 0RP of stable A, b, c, d, e,
The measured value of will give the accurate 0RP after each injection of H2O2. Therefore, by always comparing the potential after the previous application and the potential after the current application, ie, a and b, b and C. c.
and D. By comparing the potentials at times d and e, it is possible to know the time when the change is reversed, that is, when e is measured, and this is the end point 2 of the oxidation treatment reaction. The time required for the potential oscillation to disappear after each addition of H2O2 depends on the amount of waste water containing nitrite, stirring conditions, etc., but the time required can be easily determined experimentally in advance, so the time required is 0R every time
What is necessary is to measure P. Of course, a detector can also be used to detect when the potential oscillations have disappeared. Next, an embodiment in which the detection of the end point of the oxidation treatment reaction and the injection of H2O2 are automatically controlled according to the present invention will be described in detail.
第3図は上記制御に必要な装置を備えた電圧比較器Pの
プロツク線図である。以下図によつて説明すれば、先づ
0RP計4により測定された0RPは電圧比較器の入力
電圧となり、増幅器5で増幅され、測定タイミング器6
から測定開始命令のあつた時にアナログ/テイジタル変
換器(A/DCONV)7でデイジタル信号量に変換さ
れる。かくして各測定時における0RPのティジタル信
号は比較計算器(UP/DOWNCOUNTER)8で
前回測定値と今回測定値(第2図のaとB,.bとC,
.cとD,.dとe1の測定値)を比較計算し、その比
較計算値は比較器(COMPARATE)9に送られ、
こXで更にデイジタル設定器10に予め設定されている
電圧値とも比較される。比較計算器8での比較計算値が
前回測定値〉今回測定値(dとeの測定値)のとき即ち
両測定値の変化が増加より減少に逆転し、かつこの変化
量(差)がデイジタル設定器10に予め設定されている
電圧値よりも大なるときに継電器(RY)11が作動さ
れ以後のH2O2投入が中止される。若しこの差がデイ
ジタル設定器10の設定電圧値より小なる時は継電器1
1は作動せず間欠的H2O2投入は続く。而してデイジ
タル設定器10は計器測定誤差によつて自動制御が誤作
動するのを防ぐために設けられたものである。若し前回
測定値と今回測定値との電位変化量(差)が計器測定誤
差(例えば電気ノイズ、排水中にセツトされた0RP電
極への不純物付着等の原因による)の範囲内に入る如き
小さな変化しかしなかつた場合には、この電位変化が増
加していても減少即ち逆転していると誤判断され、デイ
ジタル設定器の設定電圧の働がなければ継電器は誤作動
してしまうおそれがある。よつてデイジタル設定器を設
けて比較器9から出た両測定値の差がデイジタル設定器
の設定電圧よりも大きい時にのみ継電器が作動するよう
にした。以上の如きこの発明による方法で処理量5m3
の排水中に35%H2O2を1回の投入量200m1、
投人時間16sec/回、投入間隔約110sec、0
RP測定タイム5sec/回、でデイジタル設定器の設
定電圧を0.05mvとして処理し、処理後のCODは
10ppm以下となつた。FIG. 3 is a block diagram of a voltage comparator P equipped with the necessary devices for the above control. To explain with reference to the diagram below, the 0RP measured by the 0RP meter 4 becomes the input voltage of the voltage comparator, is amplified by the amplifier 5, and is amplified by the measurement timing device 6.
When a measurement start command is received from , it is converted into a digital signal amount by an analog/digital converter (A/DCONV) 7. In this way, the digital signal of 0RP at each measurement time is calculated by the comparison calculator (UP/DOWN COUNTER) 8, which compares the previous measurement value and the current measurement value (a and B, .b and C in Fig. 2,
.. c and D,. The measured values of d and e1 are compared and calculated, and the comparison calculation value is sent to a comparator (COMPARATE) 9.
This is further compared with the voltage value preset in the digital setting device 10. When the comparison calculation value in the comparison calculator 8 is greater than the previous measurement value > the current measurement value (measurement values of d and e), that is, the change in both measurement values is reversed from increase to decrease, and this amount of change (difference) is digital. When the voltage is higher than the voltage value preset in the setting device 10, the relay (RY) 11 is activated and the subsequent injection of H2O2 is stopped. If this difference is smaller than the set voltage value of digital setting device 10, relay 1
1 does not operate and intermittent H2O2 injection continues. The digital setting device 10 is provided to prevent automatic control from malfunctioning due to instrument measurement errors. If the potential change (difference) between the previous measurement value and the current measurement value is within the range of instrument measurement error (e.g. due to electrical noise, impurity adhesion to the 0RP electrode set in the drainage water, etc.) If there is only a change in potential, it may be erroneously determined that the change in potential is decreasing or reversing even though it is increasing, and the relay may malfunction if the setting voltage of the digital setting device does not work. Therefore, a digital setting device is provided so that the relay is activated only when the difference between the two measured values output from the comparator 9 is greater than the set voltage of the digital setting device. Through the method according to the present invention as described above, the processing amount is 5 m3.
Add 35% H2O2 into the wastewater at a time of 200ml,
Throwing time: 16sec/time, Throwing interval: approx. 110sec, 0
The RP measurement time was 5 sec/time, and the set voltage of the digital setting device was set to 0.05 mV, and the COD after processing was 10 ppm or less.
H2O2連続投入の従来の方法で上記と同様の排水を処
理したところCODは40〜100ppmであつた。明
らかにこの発明による処理方法は従来の方法よりも勝つ
ている。尚上記自動制御の実施例では0RP値をデイジ
タル信号に変換してデイジタル量で以て制御したのは制
御が比較的容易でしかも精度が良いためであるが、デイ
ジタル量に変換せずに0RP値をアナログ量の侭で用い
られる事は言うまでもない。When the same wastewater as above was treated using the conventional method of continuously adding H2O2, the COD was 40 to 100 ppm. Clearly, the processing method according to the invention has advantages over conventional methods. In the automatic control example described above, the 0RP value was converted into a digital signal and controlled using the digital quantity because the control was relatively easy and the accuracy was good. Needless to say, it can be used as an analog quantity.
以上詳述せし如く、この発明による排水の処理方法は、
完全処理に近く、処理精度に個人差なく、自動化による
無人運転ができて、工業土有効である。As detailed above, the method for treating wastewater according to the present invention is as follows:
It is close to complete processing, there are no individual differences in processing accuracy, and unmanned operation is possible through automation, making it effective in industrial environments.
第1図は、過酸化水素(H2O2)の連続投入による酸
化還元電位(0RP)の変化を表した図表であり、第2
図は、この発明によるH2O2の間欠的投入に伴う0R
Pの変化を表した図表であり、第3図は、この発明によ
る各種制御装置を備えた電圧比較器Pのプロツク線図で
ある。
1:酸化還元電位(0RP)、2:処理反応終点、3:
安定時の酸化還元電位(0RP)、4:酸化還元電位測
定計器(0RP計)、5:増幅器(AMP)、6:測定
タイミング器、7リアナログ/デイジタル変換器(A/
DCONV)、8:比較計算器(UP/DOWNCOU
NTER)、9:比較器(COMPARATE)、10
:テイジタル設定器、11:継電器(RY)。Figure 1 is a chart showing changes in oxidation-reduction potential (0RP) due to continuous injection of hydrogen peroxide (H2O2).
The figure shows 0R due to intermittent injection of H2O2 according to the present invention.
3 is a diagram showing changes in P, and FIG. 3 is a block diagram of a voltage comparator P equipped with various control devices according to the present invention. 1: Redox potential (0RP), 2: Treatment reaction end point, 3:
Redox potential at stable time (0RP), 4: Redox potential measuring instrument (0RP meter), 5: Amplifier (AMP), 6: Measurement timing device, 7 Real analog/digital converter (A/
DCONV), 8: Comparison calculator (UP/DOWNCOU
NTER), 9: Comparator (COMPARATE), 10
: Digital setting device, 11: Relay (RY).
Claims (1)
亜硝酸塩を酸化せしめる排水処理方法において、一定量
の排水中に含まれる亜硝酸塩を完全に酸化するに必要な
量より充分少ない量の過酸化水素を間欠的に排水中に投
入し、各投入後における酸化還元電位の振動がなくなつ
た時の電位を測定し、この電位と前回投入後の電位との
電位変化が逆転した時点で過酸化水素の投入を中止する
事を特徴とする排水の処理方法。 2 上記電位変化が逆転した時の電位変化量が所定量よ
り大きい時に過酸化水素の投入を中止する事を特徴とす
る特許請求の範囲第1項記載の排水の処理方法。 3 前記酸化還元電位を酸化還元電位計で測定し、この
測定電圧を増幅器で増幅し、過酸化水素の各投入後、測
定タイミング器より測定開始命令信号が発せられた時に
、増幅された上記測定電圧をアナログ/ディジタル変換
器でディジタル量に変換し、このディジタル量を比較計
算器に記憶し、該比較計算器でこのディジタル量と前回
投入後の測定電圧のディジタル量との変化量を算出し、
この変化量が逆転する迄過酸化水素の間欠投入を続け、
逆転した時点以後の過酸化水素投入を中止する事を特徴
とする特許請求の範囲第1項記載の排水の処理方法。 4 上記逆転時の変化量とディジタル設定器に予め設定
してある所定量とを比較器で比較し、該変化量が該所定
量より大きい時に継電器を作動させ、過酸化水素の投入
を中止する事を特徴とする特許請求の範囲第3項記載の
排水の処理方法。[Scope of Claims] 1. In a wastewater treatment method in which hydrogen peroxide is added to and mixed with wastewater containing nitrite to oxidize the nitrite, the amount of water required to completely oxidize the nitrite contained in a certain amount of wastewater is Inject hydrogen peroxide in an amount sufficiently smaller than the amount of hydrogen peroxide into the wastewater intermittently, measure the potential when the oxidation-reduction potential no longer oscillates after each addition, and calculate the potential between this potential and the potential after the previous addition. A wastewater treatment method characterized by stopping the addition of hydrogen peroxide when the change is reversed. 2. The wastewater treatment method according to claim 1, wherein the addition of hydrogen peroxide is stopped when the amount of potential change when the potential change is reversed is larger than a predetermined amount. 3. The redox potential is measured with a redox potential meter, this measured voltage is amplified with an amplifier, and after each injection of hydrogen peroxide, when a measurement start command signal is issued from a measurement timing device, the amplified measurement voltage is The voltage is converted into a digital quantity using an analog/digital converter, this digital quantity is stored in a comparison calculator, and the comparison calculator calculates the amount of change between this digital quantity and the digital quantity of the measured voltage since the previous input. ,
Continue to add hydrogen peroxide intermittently until this amount of change is reversed,
2. A method for treating wastewater according to claim 1, characterized in that the addition of hydrogen peroxide is stopped after the point of reversal. 4 Compare the amount of change during the above reverse rotation with a predetermined amount preset on the digital setting device using a comparator, and when the amount of change is greater than the predetermined amount, activate the relay and stop adding hydrogen peroxide. A method for treating wastewater according to claim 3, characterized in that:
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP54041057A JPS5925635B2 (en) | 1979-04-06 | 1979-04-06 | How to treat wastewater |
DE19792930442 DE2930442A1 (en) | 1978-07-29 | 1979-07-26 | WASTEWATER TREATMENT METHOD |
GB7926180A GB2027004B (en) | 1978-07-29 | 1979-07-27 | Method of treating nitrate-containing waste water |
US06/061,263 US4268397A (en) | 1978-07-29 | 1979-07-27 | Method of treating waste water |
FR7919496A FR2433484A1 (en) | 1978-07-29 | 1979-07-27 | PROCESS FOR TREATING WASTEWATER |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP54041057A JPS5925635B2 (en) | 1979-04-06 | 1979-04-06 | How to treat wastewater |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS55134694A JPS55134694A (en) | 1980-10-20 |
JPS5925635B2 true JPS5925635B2 (en) | 1984-06-19 |
Family
ID=12597775
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP54041057A Expired JPS5925635B2 (en) | 1978-07-29 | 1979-04-06 | How to treat wastewater |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS5925635B2 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0453108Y2 (en) * | 1986-07-18 | 1992-12-14 |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6475373B1 (en) | 1999-04-08 | 2002-11-05 | Mitsubishi Gas Chemical Company, Inc. | Method of controlling NOx gas emission by hydrogen peroxide |
KR100471977B1 (en) * | 2000-08-24 | 2005-03-07 | 재단법인 포항산업과학연구원 | Chemical oxygen demand control method of the scrubbing water |
-
1979
- 1979-04-06 JP JP54041057A patent/JPS5925635B2/en not_active Expired
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0453108Y2 (en) * | 1986-07-18 | 1992-12-14 |
Also Published As
Publication number | Publication date |
---|---|
JPS55134694A (en) | 1980-10-20 |
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