JP2009255078A - Treatment device and treatment method for organic phosphorous based pesticide-containing water - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a treatment device and a treatment method for organic phosphorous based pesticide-containing water where, first, OH radicals are efficiently produced, thus an organic phosphorous based pesticide can be securely oxidized and decomposed, and secondary, the above operations can be achieved under excellent running cost, posttreatment cost, easiness of control, stability of treatment, initial cost or the like. <P>SOLUTION: In the treatment device 2 and the treatment method, an organic phosphorous based pesticide 1 comprised in treatment water 3 is oxidized and decomposed based on a Fenton process. Then, the treatment device 2 is provided with: a treatment tank 4; and a treatment water feeding means 5, a hydrogen peroxide adding means 6, an iron ion adding means 7 and a pH regulating means 8 attached to the treatment tank 4. Regarding the hydrogen peroxide adding means 6, hydrogen peroxide is added to the treatment water 3 in the treatment tank 4, regarding the iron ion adding means 7, bivalent ion ions are added to the treatment water 3, and, regarding the pH regulating means 8, a pH regulator is added to the treatment water 3, and the treatment water 3 is retained to prescribed weak acidity. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a treatment apparatus and treatment method for water containing organophosphorus pesticides. That is, the present invention relates to a processing apparatus and a processing method for oxidizing and decomposing an organic phosphorus-based agricultural chemical contained in wastewater contaminated with an organic phosphorus-based agricultural chemical based on the Fenton method.

《Technical background》
For example, pesticides such as herbicides, fungicides (plant disease prevention agents), fungicides, insecticides (pest control agents), rodenticides (animal control agents), plant growth regulators (plant hormone agents), soil disinfectants, It is used in large quantities in modernized agriculture.
In other words, pesticides are a general term for drugs used for the purpose of preventing and taking measures against insect damage and diseases of crops, stable supply and long-term storage of crops, simplification of weeding, etc. It is used a lot.
On the other hand, pesticides have a danger of showing strong toxicity to the human body and the environment, and substances that can be used as pesticides are regulated by law.

By the way, pesticides that can be used at present are in a situation where there are concerns about adverse effects on the human body, ecosystem, environment, etc. when they are discharged or discharged into the natural environment.
That is, pesticides are persistent organic compounds having characteristics that are difficult to be decomposed in the natural environment, and are likely to remain in the natural environment, causing environmental pollution and water pollution. In addition, it has the characteristic of being easily accumulated in living organisms, and is harmful and dangerous to the human body (for example, as an endocrine disrupting substance as an environmental hormone or a nervous system disturbing substance).
The pesticides contained in the wastewater discharged and discharged into the natural environment remain and are mixed in river water, water treatment plant intake water, sewage treatment plant inflow water, sewage treatment plant discharge water, groundwater, lake water, etc. Recently, its detection and confirmation have been reported one after another.
Organophosphorus pesticides are an important part of such pesticides, and their persistent properties are particularly problematic.

<Conventional technology>
On the other hand, effective countermeasure technology has not been established yet. The need for the treatment of pesticides remaining and contained in wastewater and the need for treatment of wastewater contaminated with organophosphorus pesticides are expected to increase in the future. Technology has not yet been proposed.
As this type of prior art, the following degree can be grasped only slightly. First, conventional water purification plants and sewage treatment plant facilities can be considered.
In addition, as technical proposals, a technique for irradiating electromagnetic waves after adding an oxidizing agent or a reducing agent (Patent Document 1 below), a wastewater treatment technique for golf courses in which many containers are filled with adsorbents such as activated carbon (described below) Technical document 2), a technique of decomposing using an alkali metal (technical document 3 below), a technique of Fenton method for generating and decomposing OH radicals with hydrogen peroxide and an iron salt, etc. are only occasionally seen.

《Information on prior art documents》
JP 2006-26460 A JP-A-4-256488 JP 2005-160709 A

About the problem
By the way, the following problems have been pointed out for this type of conventional example.
First, it has been considered to be difficult to treat persistent organophosphorus pesticides with facilities, capabilities, chemicals used, etc. of conventional water treatment plants and sewage treatment plants.
For technology that irradiates electromagnetic waves after addition of oxidizing agent or reducing agent, technology that adsorbs on activated carbon, etc., technology that uses alkali metal, etc., equipment cost, other initial costs, control complexity, processing stability, processing efficiency, etc. The problem was pointed out.
The conventional Fenton method has been pointed out in terms of processing performance, running cost (chemical use cost), and the like. For example, hydrogen peroxide is easily decomposed into water and oxygen during the treatment, and the generation efficiency of OH radicals is poor, and a large amount of hydrogen peroxide is excessively added to cover this. The post-processing cost by the agent was also increased.

<< About the present invention >>
The treatment apparatus and treatment method for organophosphorus agrochemical-containing water of the present invention have been made in order to solve the problems of the above-described conventional examples in view of such a situation.
The first aspect of the present invention is that OH radicals are efficiently generated, and the organophosphorus pesticide can be reliably oxidized and decomposed. Secondly, this is a running cost, a post-processing cost, and a control. It is an object to propose a treatment apparatus and treatment method for water containing organophosphorus pesticides, which is realized with excellent ease, stability of treatment, initial cost, and the like.

<About each claim>
The technical means of the present invention for solving such problems, that is, the technical means described in the claims are as follows. First, claim 1 is as follows.
The apparatus for treating organophosphorus pesticide-containing water according to claim 1 oxidizes and decomposes the organophosphorus pesticide contained in the water to be treated based on the Fenton method.
The organophosphorus pesticide consists of an organic compound containing nitrogen and phosphorus. The treatment apparatus includes a treatment tank and water to be treated, a hydrogen peroxide addition means, an iron ion addition means, and a pH adjustment means attached to the treatment tank.
The treated water supply means supplies the treated water containing the organophosphorus pesticide to the treatment tank. The hydrogen peroxide adding means adds hydrogen peroxide to the water to be treated in the treatment tank. The iron ion addition means adds divalent iron ions to the water to be treated in the treatment tank.
The pH adjusting means adds a pH adjusting agent to the treated water supplied to the treated tank from the treated water supply means and the treated water supplied to the treated tank, and the treated water Is maintained at a predetermined weak acidity.

About Claim 2, it is as follows. In the treatment apparatus for water containing organophosphorus pesticides according to claim 2, in claim 1, the hydrogen peroxide addition means adds a total amount of an aqueous solution of hydrogen peroxide at the beginning of the reaction. The iron ion addition means repeats a plurality of cycles intermittently after the addition of hydrogen peroxide, and adds the divalent iron ion solution in portions.
The pH adjusting means is characterized in that an acid pH adjuster is added before the addition of hydrogen peroxide, and an alkaline pH adjuster is added every time an iron ion solution is added after the addition of hydrogen peroxide. And
About Claim 3, it is as follows. According to a third aspect of the present invention, the organophosphorus pesticide comprises fenitrothion, phosphonomethylglycine, methamidophos, methyl dimethone, dichlorvos or parathion.
The iron ion adding means adds an aqueous solution of ferrous sulfate or ferrous chloride. The pH adjusting means adds sulfuric acid or caustic soda, for example, and maintains the water to be treated in the treatment tank at about pH 4 to suppress decomposition reaction of the added hydrogen peroxide into water and oxygen. It is characterized by.

About Claim 4, it is as follows. The method for treating organophosphorus pesticide-containing water according to claim 4 oxidizes and decomposes the organophosphorus pesticide contained in the water to be treated based on the treatment process of the Fenton method. The organophosphorus pesticide consists of an organic compound containing nitrogen and phosphorus.
Then, hydrogen peroxide, a divalent iron ion solution, and a pH adjuster are added to the water to be treated containing the organophosphorus pesticide. The total amount of hydrogen peroxide is added at the beginning of the reaction. The divalent iron ion solution is added in portions by repeating a plurality of cycles intermittently after the addition of hydrogen peroxide.
As for the pH adjuster, an acid pH adjuster is added before the addition of hydrogen peroxide, and after the addition of hydrogen peroxide, an alkaline pH adjuster is added for each divided addition of the divalent iron ion solution. The water is maintained at a predetermined weak acidity.

About Claim 5, it is as follows. In the method for treating water containing organophosphorus agrochemicals according to claim 5, in claim 4, hydrogen peroxide added in whole amount is reduced with divalent iron ions dividedly added as a catalyst at each divided addition, OH radicals are generated.
Thus, the organophosphorus pesticide contained in the water to be treated is oxidized and decomposed by the OH radicals to be mineralized into a low molecular weight compound.
About Claim 6, it is as follows. In the method for treating organophosphorus pesticide-containing water according to claim 6, in claim 5, the hydroxide ions produced by the reduction reaction of hydrogen peroxide are further produced by the oxidation reaction of divalent iron ions. It is oxidized by trivalent iron ions to generate OH radicals.
Thus, the organophosphorus pesticide contained in the water to be treated is oxidized and decomposed by the OH radicals to be mineralized into a low molecular weight compound.
About Claim 7, it is as follows. In the method for treating water containing organophosphorus pesticides according to claim 7, in claim 5 or 6, the generated OH radical further reacts with water such as the water to be treated, to thereby produce new OH radical and water. The resulting reaction is repeated in a chain.
Thus, the organophosphorus pesticide is oxidized and decomposed by the OH radicals newly generated repeatedly as described above, and is mineralized into a low molecular weight compound.
About Claim 8, it is as follows. In the method for treating organophosphorus pesticide-containing water according to claim 8, in claim 5 or 6, trivalent iron ions generated by oxidation reaction of divalent iron ions react with hydrogen peroxide. The reaction that generates at least new OH radicals is repeated in a chain.
Thus, the organophosphorus pesticide is oxidized and decomposed by the OH radicals newly generated repeatedly as described above, and is mineralized into a low molecular weight compound.

<About the action>
Since the present invention comprises such means, the following is achieved.
(1) Water to be treated containing organophosphorus pesticides such as phosphonomethylglycine, methamidophos, and parathion is supplied to the treatment equipment. The organophosphorus pesticide is oxidized and decomposed by a treatment method based on the Fenton method.
(2) First, the treatment apparatus includes a water to be treated supply means, a treatment tank, a post-treatment tank, and the like.
The treatment tank is provided with hydrogen peroxide addition means, iron ion addition means, pH adjustment means, and the like.
(3) And the water to be treated is supplied to the treatment tank, but before that, sulfuric acid or the like is added from the pH adjusting means to make it weakly acidic at about pH 4.
(4) In the treatment tank, first, all the hydrogen peroxide is added from the hydrogen peroxide addition means to the water to be treated.
(5) Then, a divalent iron ion solution is dividedly added from the iron ion adding means, and for each divided addition, caustic soda or the like is added from the pH adjusting means, and the weak acidity of the water to be treated is maintained. .
(6) Now, in the treatment tank, hydrogen peroxide generates OH radicals using divalent iron ions as a catalyst. In this generation reaction, since iron ions are added in portions, there is no possibility of a reaction that wastes OH radicals and iron ions. Further, since the atmosphere is weakly acidic, the catalytic function of iron ions is promoted, so that hydrogen peroxide is not decomposed or wasted into water and oxygen.
(7) OH radicals can also be generated by the reaction of trivalent iron ions and hydroxide ions generated by the above reaction.
(8) The OH radical is further formed by the reaction of the OH radical generated by the above reaction with water such as water to be treated, or the trivalent iron ion and hydrogen peroxide generated by the above reaction. Also by reacting, new products are repeatedly generated in a chain.
(9) In the treatment tank, a large amount of OH radicals are generated by such a chain reaction, and due to the strong oxidizing power of the generated OH radicals, organophosphorus pesticides contained in the water to be treated are difficult. Although it consists of degradable organic compounds, it is reliably oxidized and decomposed. Thus, it is mineralized into water, carbon dioxide, and other low-molecular compounds.
(10) Then, the water to be treated is drained outside through the post-treatment tank.
(11) In this processing apparatus and processing method, the addition amount of the Fenton reagent and the like can be easily calculated from the reaction theoretical value, the configuration is relatively simple, and stable processing is possible.
(12) Then, the processing apparatus and the processing method of the present invention exhibit the following effects.

<< First effect >>
First, OH radicals are efficiently generated, so that the organophosphorus pesticide can be reliably oxidized and decomposed.
That is, in the processing apparatus and processing method of the present invention, first, a. OH radicals are efficiently generated by maintaining the weak acidity of the water to be treated, adding all of the hydrogen peroxide, split addition of divalent iron ions, and the like. And b. The OH radical repeats in a chain by the reaction of trivalent iron ions and hydroxide ions, the reaction of the generated OH radicals with water, the reaction of trivalent iron ions with hydrogen peroxide, etc. Produced with high efficiency.
With these a and b, OH radicals generated in a large amount by a chain reaction reliably oxidize, decompose, and remove the organophosphorus pesticide remaining, mixed, and contained in the water to be treated such as waste water. Wastewater contaminated with organophosphorus pesticides will be reliably detoxified.

<< Second effect >>
Secondly, such reliable oxidation and decomposition of the organophosphorus pesticide is realized with excellent running cost, post-treatment cost, ease of control, stability of treatment, initial cost, and the like.
That is, in the processing apparatus and processing method of the present invention, first, a. Like the Fenton method of this type, the hydrogen peroxide is not decomposed and wasted into water and oxygen, and it is not necessary to add an excessive amount of hydrogen peroxide. Cost and running cost are reduced. B. Like this conventional Fenton method, hydrogen peroxide is not added excessively, the water to be treated after treatment has a small residual content of hydrogen peroxide, and the post-treatment cost by the neutralizing agent is also reduced. .
C. The addition amount of hydrogen peroxide corresponding to the content of organophosphorus pesticides, the addition amount of divalent iron ions corresponding to the addition amount of hydrogen peroxide, the addition amount of pH adjuster, etc. are based on theoretical reaction values. It is easily calculated and the required number of moles is obtained. Therefore, it is easy to control the addition of an appropriate amount of chemicals without excess and deficiency, and automatic control is possible. For example, there is no situation where divalent iron ions remain or run short, and the processing is stabilized. .
D. Compared to this type of conventional example described above, the configuration is relatively simple and easy, and in this respect as well, the processing stability is excellent, and initial costs such as equipment costs and other various costs are reduced.
The processing apparatus and the processing method of the present invention open the way to scale-up application to full-scale processing, large-scale processing, large-capacity processing, etc., that is, practical application, from each of a, b, c, d. For example, by installing the treatment apparatus of the present invention in a facility and carrying out the treatment method of the present invention, it is possible to easily purify wastewater containing an organophosphorus pesticide.
As described above, the effects exerted by the present invention are remarkably large, such as all the problems existing in this type of conventional example are solved.

《About drawing》
Hereinafter, the treatment apparatus and treatment method for organophosphorus pesticide-containing water according to the present invention will be described in detail based on the best mode for carrying out the invention shown in the drawings.
FIG. 1 is a configuration flowchart for explaining the best mode for carrying out the present invention.

<< About organophosphorus pesticides 1 >>
First, the organophosphorus pesticide 1 that is a treatment target of the treatment apparatus 2 and the treatment method of the present invention will be described.
Organophosphorus pesticide 1 consists of an organic compound containing nitrogen (N) and phosphorus (P), and constitutes a major field of agrochemicals together with organochlorine pesticides and organosulfur pesticides (for pesticides, See above for technical background).
The organophosphorus pesticide 1 is particularly difficult to decompose, and specific examples include fenitrothion (C ₉ H ₁₂ O ₅ NPS), phosphonomethylglycine (C ₃ H ₇ O ₅ NP), methamidophos (C ₂ H). ₈ O ₂ PSN), parathion (C ₁₀ H ₁₄ NO ₅ PS), methyl dimethone (C ₆ H ₁₅ O ₃ PS ₂ ), dichlorvos and the like.
A typical example is phosphonomethylglycine (glyphosate isopropylamine salt), which is known as an organophosphorus and amino acid herbicide, and is used together with water and surfactant (1,4 dioxane). 48% vs. 52%).
Phosphonomethylglycine is a compound of glycine (HOOC—CH ₂ —NH ₂ ) and phosphonomethyl (CH ₃ —P— (O) (OH) ₂ ) which is a derivative of phosphoric acid (H ₃ PO ₄ ). In which the hydrogen atom (H) of the amino group (—NH ₂ ) of glycine is substituted with a phosphonomethyl group (its structural formula: HOOC—CH ₂ —NH—CH ₂ —P— (O) (OH) ₂ )).
Although parathion (diethyl / nitrophenyl / thiophosphoric acid) is currently prohibited in Japan in view of its toxicity, detection of methylparathion has been reported recently.
The present invention is directed to such organophosphorus pesticides 1 contained in various types of wastewater.

<< Outline of Processing Apparatus 2 and Processing Method >>
The treatment apparatus 2 and the treatment method of the present invention oxidize and decompose the organophosphorus pesticide 1 contained in the water 3 to be treated based on the improved Fenton treatment process. That is, in the treatment apparatus 2 and the treatment method of the present invention, the water containing the organophosphorus pesticide 1 is treated water 3.
Therefore, the organophosphorus pesticide 1 contained in the fenton reagent hydrogen peroxide (H ₂ O ₂ ) and divalent iron ions (Fe ²⁺ ), OH radicals generated by the Fenton main reaction (.OH) Or, it is oxidized and decomposed by OH radicals generated by the incidental, secondary and chain reactions of such a Fenton main reaction, thereby mineralizing it into water, carbon dioxide and other low molecular weight compounds.
And the processing apparatus 2 and the processing method of this invention are the processing tank 4, the to-be-processed water supply means 5, the hydrogen peroxide addition means 6, the iron ion addition means 7, and the pH adjustment means 8 which were attached to this processing tank 4. And has.
Hereinafter, these will be described in detail.

<< About treated water supply means 5 etc. >>
First, the treated water supply means 5 and the like will be described. The treated water supply means 5 supplies the treated water 3 containing the organophosphorus pesticide 1 to the treatment tank 4 as a treatment target.
That is, in the illustrated example, the treated water 3 is introduced into the raw water tank 9 of the treated water supply means 5, and the treated water 3 is supplied to the treated tank 4 via the raw water tank 9 and the pH adjustment tank 10. Is supplied. The treated water 3 introduced into the raw water tank 9 is subjected to pretreatment such as dust sludge removal and biological treatment in advance as necessary. In the pH adjusting tank 10, a pH adjusting agent is added from the attached pH adjusting means 8.
The pH adjusting means 8 adds a pH adjusting agent to the treated water 3 being supplied from the raw water tank 9 of the treated water supply means 5 to the treated tank 4 so as to reduce the treated water 3 to a predetermined weakness. After adjusting to acidity, it is supplied to the treatment tank 4. That is, the treated water 3 from the raw water tank 9 is often pH 6 or more, for example, so that the pH is adjusted to about pH 5 to about 3, typically about pH 4, so that an acid pH such as sulfuric acid is used as a pH adjuster. A modifier is used.
The reason for adjusting the pH in advance in this way is that, as will be described later, in order to ensure that the OH radical production reaction with hydrogen peroxide and divalent iron ions is performed efficiently as expected. is there. In addition, although the said pH adjustment tank 10 is used, for example in the case of the large volume process of the to-be-processed water 3, a continuous process, the process of the high concentration organophosphorus pesticide 1, etc., the pH adjustment tank 10 is used. Instead, the above-described pH adjustment can be performed in the raw water tank 9 as a substitute or a combination.
The treated water supply means 5 and the like are as described above.

<About hydrogen peroxide addition means 6>
Next, the hydrogen peroxide addition means 6 attached to the processing tank 4 will be described. The hydrogen peroxide addition means 6 adds a total amount of an aqueous solution of hydrogen peroxide (H ₂ O ₂ ) to the treated water 3 in the treatment tank 4 as a Fenton reagent at the beginning of the reaction. Hydrogen peroxide is a source of OH radicals.
The amount of hydrogen peroxide added per reaction depends on the specific content and concentration of the organophosphorus pesticide 1 to be treated contained in the treated water 3, but it is based on the theoretical reaction value. The actual required amount (necessary number of moles) that is calculated as the most is added all at once at the beginning of the reaction. The next addition is when hydrogen peroxide is exhausted from the water 3 to be treated in the treatment tank 4, that is, at the next reaction, and the whole amount is added in the same manner. Thus, in this specification, the addition of the total amount means that 100% of the total amount of the drug necessary for the reaction is added all at once.
In this way, the entire amount of hydrogen peroxide is added from the hydrogen peroxide addition means 6.

<< About iron ion addition means 7 >>
Next, the iron ion addition means 7 attached to the processing tank 4 will be described. The iron ion adding means 7 intermittently repeats a plurality of cycles with respect to the water to be treated 3 of the treatment tank 4 after the addition of hydrogen peroxide as described above, thereby supplying a divalent iron ion (Fe ²⁺ ) solution to Fenton. Add in portions as reagents.
That is, substances that generate divalent iron ions in the liquid, such as ferrous sulfate heptahydrate (FeSO ₄ · 7H ₂ O), are typically used as such iron salts, but other anhydrous Salts and hydrated salts such as iron chloride (FeCl ₂ ) and hydrates thereof can also be used. The divalent iron ion functions as a catalyst for the OH radical generation reaction of hydrogen peroxide. The amount of iron ion added per reaction is calculated based on the theoretical reaction value, but the actual required amount is larger, for example, about 0.5 mole per mole of hydrogen peroxide. .
Moreover, this iron ion is divided and added in multiple times. That is, the necessary amount for one reaction is not added in the whole amount, but is divided into about 3 to 7 times, for example, 5 times, and is added sequentially. As for the addition timing for each time, the next time is added at the stage where the previous addition is gone. Thus, in this specification, divided addition means that the amount of drug necessary for the reaction is added in multiple portions.
The reason why the divalent iron ions are added separately is as follows: a, b, c. First a. If the total amount is added, in the chemical reaction to be described later, the OH radical is wasted at the same time as the intended positive reaction from the original system using hydrogen peroxide as a reactant to the production system using OH radical as a product. Reaction is likely to occur. That is, a reaction in which surplus OH radicals return to water easily occurs, loss occurs, and iron ions used for generating OH radicals are wasted. On the other hand, when the addition is divided, such a reaction is suppressed and the waste of iron ions is eliminated.
B. OH radicals have a very short reaction time due to their intense reaction, and have a very short life. When the total amount is added in a divided manner, OH radicals are generated each time, and the corner of the treated water 3 in the treatment tank 4 is generated. I will come across. As a result, the oxidation and decomposition of the organophosphorus pesticide 1 are ensured, made efficient, and accelerated. C. When the addition is divided, the remaining hydrogen peroxide is smaller than the total addition, and accordingly, the post-treatment cost by the neutralizing agent is reduced accordingly.
In this way, divalent iron ions and the like are dividedly added from the iron ion adding means 7.

<About pH adjusting means 8>
Next, the pH adjusting means 8 attached to the processing tank 4 will be described. The pH adjusting means 8 adjusts the pH of the water to be treated 3 before being supplied from the water to be treated supplying means 5 to the treatment tank 4 and the water to be treated 3 after being supplied to the treatment tank 4 as described above. An agent is added to maintain the water to be treated 3 at a weak acidity of about pH 4, for example.
That is, the pH adjusting means 8 adds an acid pH adjuster such as sulfuric acid (H ₂ SO ₄ ) before the addition of hydrogen peroxide, and after the addition of hydrogen peroxide, An alkaline pH adjuster such as caustic soda (NaOH) is added.
The reasons for maintaining the water to be treated 3 at about pH 3 to about pH 5 typically about pH 4 are as follows: a, b, c. First a. As will be described later, it functions to suppress a wasteful decomposition reaction of hydrogen peroxide into water and oxygen that inhibits the intended reaction. With this, b. It functions to promote electron donation of divalent iron ions to hydrogen peroxide. C. It functions to promote and ensure the incidental, secondary, and chain-repeated OH radical generation reactions described below. With these a, b, and c, generation of OH radicals proceeds efficiently.
On the other hand, first, the treated water 3 from the raw water tank 9 of the treated water supply means 5 is often, for example, pH 6 or higher, so that, as described above, in the pH adjusting tank 10, for example, from the pH adjusting means 8 Sulfuric acid is added to adjust the pH to about 4, for example.
Then, after the fact, when divalent iron ions are added in the treatment tank 4, the pH of the water to be treated 3 is lowered to, for example, about 2.8 and the acidity is excessively increased. For each divided addition, for example, caustic soda is added to adjust the pH of the water to be treated 3 to about pH 4, for example.
The pH adjusting means 8 is as described above.

<< Reaction in Treatment Tank 4 (OH Radical Generation: Part 1) >>
Next, the chemical reaction (generation of OH radicals: part 1) in the treatment tank 4 will be described.
In the treatment apparatus 2 and treatment method, first, in the treatment tank 4, the water 3 to be treated is stirred and flowed down, and the added hydrogen peroxide is added as a catalyst to the divalent iron ion. To generate OH radicals.
The generation of such OH radicals will be further described in detail. In the treatment tank 4, OH radicals are generated based on the following chemical formulas 1 and 2 (chemical formula 3). This is the Fenton main reaction.

These will be further described in detail. In this Fenton main reaction, the divalent iron ions (Fe ²⁺ ) sequentially added from the iron ion addition means 7 in the reaction formula of the above chemical formula 1 maintain the treated water 3 in a weakly acidic atmosphere having a pH of about 4, for example. Therefore, as a catalyst, electrons (e ⁻ ) are sequentially donated to the hydrogen peroxide (H ₂ O ₂ ) of the above reaction formula 2 as a catalyst, and the self oxidizes to trivalent iron ions ( Fe ³⁺ ).
Therefore, in the reaction formula of Chemical Formula 2, all of the hydrogen peroxide initially added from the hydrogen peroxide addition means 6 is sequentially supplied with electrons based on the chemical formula of Chemical Formula 1, and in each case, OH radical (.OH) And hydroxide ions (OH ⁻ ) are produced. When the reaction formulas of Chemical Formula 1 and Chemical Formula 2 are synthesized together, the reaction formula of Chemical Formula 3 is obtained.
By the way, in such a reaction, since the to-be-processed water 3 is maintained in the weakly acidic atmosphere as mentioned above, it is suppressed that hydrogen peroxide is decomposed | disassembled into water and oxygen, and wasted.
On the other hand, if it is not maintained in a weakly acidic atmosphere, hydrogen peroxide becomes water molecules (H ₂ O) while generating oxygen (O) in the nascent stage according to the following reaction formula 4; The reaction formula of Chemical Formula 2 (Chemical Formula 3) is wasted without generating OH radicals. It should be noted that oxygen in this nascent stage is out of the system as oxygen molecules (O ₂ ) when there is no oxidation target.
In the treatment tank 4, first, OH radicals are generated by such a Fenton main reaction.

<< Reaction in treatment tank 4 (generation of OH radicals: 2) >>
Next, the chemical reaction (generation of OH radical: part 2) in the treatment tank 4 will be described. Secondly, in the treatment tank 4, OH radicals (.OH) can be generated also by the following reaction formulas 5 and 6.
That is, in the treatment tank 4, first of all, OH radicals are generated by the Fenton main reaction in the reaction formula of the chemical formula 3 (Chemical formula 1, Chemical formula 2). OH radicals can also be generated incidentally, secondaryly, or chained by the reaction formula of ## STR5 ##

This will be further described in detail. In the treatment tank 4, the hydroxide ions (OH ⁻ ) generated by the reduction reaction of hydrogen peroxide are converted into trivalent iron ions (Fe ³⁺ ) generated by the oxidation reaction of divalent iron ions. Oxidized to generate OH radicals (.OH).
That is, the trivalent iron ion generated by the chemical formula 1 is converted into an electron (e ⁻ ) from the hydroxide ion generated by the chemical formula 2 according to the chemical formula 5 and chemical formula 6 above. OH radicals are generated, and they are reduced to divalent iron ions and returned. In this way, when not only the reaction formula of Chemical Formula 3 (Chemical Formula 1, Chemical Formula 2) but also the chemical formulas of Chemical Formula 5 and Chemical Formula 6 occur in a chain-balanced manner, OH radicals are generated more efficiently. The
Secondly, in the treatment tank 4, OH radicals can be generated by such a reaction.

<< Reaction in Treatment Tank 4 (Generation of OH radical: Part 3) >>
Next, the chemical reaction (generation of OH radicals: part 3) in the treatment tank 4 will be described. In the treatment tank 4, in addition to the first and second described above, new OH radicals are generated incidentally, secondary, and chained by the third reaction.
That is, the OH radicals generated in the reaction formulas of Chemical Formula 3 (Chemical Formula 1, Chemical Formula 2) and Chemical Formula 5 and Chemical Formula 6 react with water such as the water to be treated 3 to generate new OH radicals and water. The reaction to generate is repeated in a chained manner according to the following reaction formulas 7 and 8.

These will be further described in detail. First, in a neutral to alkaline atmosphere, OH radicals extract hydrogen atoms from water molecules and oxidize them to generate oxygen molecules, and are themselves reduced to water molecules.
On the other hand, in an acidic atmosphere, the OH radical (.OH) withdraws electrons (e ⁻ ) from water molecules (H ₂ O) according to the above reaction formula (7) and converts itself into hydroxide ions (OH ⁻ ). However, this abstraction reaction radically splits and activates water molecules to generate new OH radicals (.OH) and protons (H ⁺ ). The generated hydroxide ions and protons disappear by generating new water (H ₂ O) in the reaction formula of the above formula 8.
Since the water 3 to be treated in the treatment tank 4 is maintained in a weakly acidic atmosphere, new OH radicals are generated in this way. Further, based on the OH radicals thus generated, A series of reactions like this occur in a chain, and the subsequent process is repeated in a chain.
That is, once OH radicals are generated by the reaction formulas such as Chemical Formula 3, etc., OH radicals are obtained semipermanently by a chain reaction afterwards using this as an initiation reaction and reaction initiator. The OH radical excluding the amount consumed in the oxidation and decomposition processes of the organophosphorus pesticide 1 repeats the generation and extinction in a coexistence with the chain generation and extinction of protons. Considering that the OH radical has a very short lifetime, the significance of such repeated generation is great.
Thirdly, in the treatment tank 4, OH radicals are also generated by such a reaction.

<< Reaction in Treatment Tank 4 (OH Radical Generation: Part 4) >>
Next, the chemical reaction (generation of OH radical: part 4) in the treatment tank 4 will be described. In the treatment tank 4, in addition to the first, second, and third described above, OH radicals are newly generated incidentally, subsidiaryly, and continuously by the following reaction.
That is, the reaction in which trivalent iron ions generated by the oxidation reaction of divalent iron ions react with hydrogen peroxide to newly generate OH radicals or the like is represented by the following chemical formulas 9 and 10. The reaction formula (reaction formula of Formula 11) is repeated in a chain.

These will be further described in detail. The trivalent iron ion (Fe ³⁺ ) generated by the reaction formula of Chemical Formula 3 (Chemical Formula 1) reacts with hydrogen peroxide (H ₂ O ₂ ) by the reaction formula of Chemical Formula 9 above. The iron ion is reduced to a divalent iron ion (Fe ²⁺ ), and a superoxide anion (.O ₂ ⁻ ), which is an ion generated by combining oxygen molecules with electrons, is generated. Then, according to the reaction formula of the above chemical formula 10, this radical superoxide anion can react with hydrogen peroxide to generate an OH radical (.OH). When the reaction formulas of the chemical formulas 9 and 10 are synthesized together, the chemical formula of the chemical formula 11 is obtained.
Thus, as long as the hydrogen peroxide that was the source of OH radical generation in the reaction formula of Chemical Formula 3 (Chemical Formula 2) remains, (in the oxidation and decomposition process of the organophosphorus pesticide 1, However, even if it has been consumed up, as long as hydrogen peroxide remains, new OH radicals are generated in a chain semipermanently based on the hydrogen peroxide) Will be continued. Considering that the OH radical has an extremely short lifetime, the significance of such generation continuation is great.
However, in order to ensure that the reaction formula of Chemical Formula 11 (Chemical Formula 9, Chemical Formula 10) occurs, even a weakly acidic atmosphere that does not decompose hydrogen peroxide into water and dissolved oxygen (see the chemical formula of Chemical Formula 4), A pH operation is required, such as adding caustic soda or the like to the water to be treated 3 of the treatment tank 4 by the pH adjusting means 8, and it is necessary to move the pH value to the alkali side.
Furthermore, although the divalent iron ion generated by the reaction formula of Chemical Formula 11 (Chemical Formula 9) lowers the pH, the necessary pH operation is performed in order to coexist with hydrogen peroxide that is stably present in the weakly acidic atmosphere as described above. If carried out, the generation of OH radicals can be expected by the Fenton main reaction of the reaction formula such as Chemical Formula 3 above.
In the treatment tank 3, fourthly, OH radicals are also generated by such a reaction.

<< Reaction in treatment tank 4 (oxidation and decomposition of organophosphorus pesticide 1) >>
Next, oxidation, decomposition, and mineralization of the organophosphorus pesticide 1 due to OH radicals will be described.
In the treatment apparatus 2 and the treatment method, in the treatment tank 4, the organophosphorus pesticide 1 contained in the water to be treated 3 is oxidized by the OH radicals generated in the Fenton main reaction and others in this manner. Decomposed and mineralized.
These will be described in more detail. The OH radical, that is, the hydroxy radical (.OH) has a strong oxidizing power as is well known. That is, it has an extremely strong electron (e ⁻ ) deprivation ability, oxidation ability, that is, activation ability and decomposition ability, which is unparalleled as an active oxygen species, and is highly reactive with radicals. In addition, since the reaction is intense, its existence time is a very short-lived chemical species.
Now, the OH radical dispersed in the water phase oxidizes the organophosphorus pesticide 1 contained in the water to be treated 3 and eventually decomposes. In other words, the OH radical follows the chain process of oxidation and addition of the organic structure of the organophosphorus pesticide 1 and the organic structure of the transient intermediate of its decomposition process, so that its carbon chain, organic bond, and molecular bond are sequentially It is cut, decomposed and divided, and finally oxidized, decomposed and mineralized into inorganic low molecular weight compounds.
Most of the organophosphorus pesticide 1 is oxidized, decomposed and mineralized into water and carbon dioxide. Then, the remaining small portion is oxidized, decomposed, or mineralized by a small amount of other phosphorus-based low molecular compounds or ions (for example, nitrogen dioxide or phosphate ions).
For example, phosphonomethylglycine, which is a representative example of organophosphorus pesticide 1, is converted to a monovalent anion (anion) in the water to be treated 3 in view of water solubility, and is subjected to a chain process of oxidation and addition by OH radicals. , Go sequentially. As a result, decomposition of each process residue proceeds, and water (H ₂ O) and carbon dioxide (CO ₂ ) are derived, generated and liberated along the way, and nitrogen dioxide (NO ₂ ) is also slightly increased. Derived, generated and liberated. Finally, phosphate ions (H ₂ PO ₄ ⁻ ) are generated and complexed as described later.
In the treatment tank 4, the organophosphorus pesticide 1 is thus oxidized, decomposed, and mineralized.

<< About the post-treatment tank 11 >>
Next, the post-treatment tank 11 will be described. A post-treatment tank 11 is attached to the treatment tank 4 described above. And the to-be-processed water 3 after the organophosphorus pesticide 1 is oxidized and decomposed | disassembled by the above-mentioned to this post-treatment tank 11 is discharged | emitted from the treatment tank 4, a required process is performed, and it drains outside.
Such a post-treatment tank 11 will be further described in detail. The illustrated post-treatment tank 11 includes a neutralization tank 12, a coagulation tank 13, a storage tank 14, a dehydration tank 15, a treated water tank 16, and the like in order toward the downstream.
First, the treated water 3 that has been subjected to the oxidation, decomposition, and mineralization treatment of the contained organophosphorus pesticide 1 is discharged from the treatment tank 4 to the neutralization tank 12 of the post-treatment tank 11. In the neutralization tank 12, a pH adjuster such as caustic soda is added to the water 3 to be treated, and the pH is adjusted to the optimum value for the inorganic flocculant. When hydrogen peroxide remains even in the treated water 3, a neutralizing agent such as catalase is added in order to avoid water pollution.
Next, in the coagulation tank 13, for example, polyaluminum chloride (PAC, Al ₂ (OH) _n Cl _6-n ) or ferric chloride is used as the inorganic coagulant for the water to be treated 3 flowing from the neutralization layer 12. (FeCl ₃ ) is added and stirred. Accordingly, phosphorus ions (for example, phosphate ions H ₂ PO ₄ ⁻ ) in the water to be treated 3 form a colloidal complex 17 with aluminum ions (Al ³⁺ ) and trivalent iron ions (Fe ³⁺ ), and agglomerate. , Precipitate, deposit, can be separated and removed.
In addition, when there is much residual amount of the trivalent iron ion which generate | occur | produced by the Fenton method in the to-be-processed water 3, since this iron ion functions as an inorganic flocculant, the addition of the said inorganic flocculant is unnecessary. On the other hand, for example, an anion may be added as a polymer flocculant to further agglomerate and flock the complex 17.
Then, the water 3 to be treated is supplied from such a coagulation tank 13 to the dehydration tank 15 via the storage tank 14 in the illustrated example. In the dehydration tank 15, the treated water 3 that has been precipitated and sludged into solid and liquid separated by, for example, an F / P-type dehydrator and floculated and dehydrated cake 17 is separated and stored in the container 18. Removed.
And the to-be-processed water 3 purified in this way is further purified in the treated water tank 16, and after having been adjusted to a pH value suitable for external discharge, it is discharged externally.
The post-treatment tank 11 is as described above.

《Action etc.》
The treatment apparatus 2 and treatment method for water containing organophosphorus pesticide 1 according to the present invention are configured as described above. Therefore, it becomes as follows.
(1) Water to be treated 3 such as waste water containing an organophosphorus pesticide 1 such as phosphonomethylglycine, methamidophos, parathion or the like is supplied to the treatment device 2. The treatment device 2 purifies the water to be treated 3 by oxidizing and decomposing the organophosphorus pesticide 1 that has remained and mixed in by a treatment method based on the treatment process of the Fenton method.

  (2) First, the treatment apparatus 2 includes a raw water tank 9, a pH adjustment tank 10, a treatment tank 4, a post-treatment tank 11, and the like of the treated water supply unit 5 in order. The pH adjusting tank 10 is provided with pH adjusting means 8. The treatment tank 4 is provided with hydrogen peroxide adding means 6, iron ion adding means 7, pH adjusting means 8, and the like.

  (3) Therefore, the treated water 3 is supplied from the raw water tank 9 of the treated water supply means 5 to the treatment tank 4. In addition, before the water 3 to be treated is supplied to the treatment tank 4, in the illustrated example, in the pH adjustment tank 10, an acid pH adjuster such as sulfuric acid is added from the pH adjustment means 8, so that the pH is about 3 to about 5 such as about pH 4. It is considered to be slightly acidic.

  (4) First, an aqueous solution of hydrogen peroxide is added from the hydrogen peroxide adding means 6 to the water to be treated 3 supplied to the treatment tank 4. The total amount of hydrogen peroxide is added at the beginning of the reaction.

(5) In the treatment tank 4, after the hydrogen peroxide is added in this way, a divalent iron ion solution is added from the iron ion addition means 7 to the water to be treated 3. This addition is performed by repeating a plurality of cycles intermittently divided into a plurality of times by divided addition during the reaction after the addition of hydrogen peroxide.
Further, for each divided addition of iron ions, an alkaline pH adjusting agent such as caustic soda is added from the pH adjusting means 8 so that the water to be treated 3 always maintains a weak acidity of about pH 4, for example. That is, the water to be treated 3 is adjusted to an optimum pH for generating OH radicals.

(6) Now, in the treatment tank 4, a large amount of OH radicals are generated based on the following first, second, third and fourth reactions.
First, the total amount of hydrogen peroxide added as described above is reduced by divalent iron ions added in portions as a catalyst, and OH radicals are generated each time the addition is performed.
That is, by the Fenton main reaction in the reaction formula of Chemical Formula 3 (Chemical Formula 1, Chemical Formula 2), the divalent iron ion donated an electron to hydrogen peroxide to become a trivalent iron ion, and the electron was donated. Hydrogen peroxide generates OH radicals. The generation of OH radicals is carried out efficiently without waste, since there is no risk of wasteful reaction of OH radicals and divalent iron ions because divalent iron ions are added in portions. Is done.
In addition to this, the generation of OH radicals is more efficiently and reliably performed by being maintained in a weakly acidic atmosphere having a pH of about 4. That is, under the weak acid atmosphere, first, electron donation of divalent iron ions is promoted, and further, hydrogen peroxide is decomposed into water and oxygen by the reaction formula (4) and is wasted. Suppressed and avoided, generating full-capacity OH radicals.

(7) Second, OH radicals are hydroxylated by a reduction reaction of hydrogen peroxide with trivalent iron ions generated by an oxidation reaction of divalent iron ions in the treatment tank 4. Ions can also be generated by oxidation.
That is, OH radicals can be generated by the reaction formulas of Chemical Formula 5 and Chemical Formula 6 based on the trivalent iron ions and hydroxide ions generated by the reaction formula of Chemical Formula 3 (Chemical Formula 1, Chemical Formula 2). From this aspect, OH radicals are efficiently generated. The OH radicals are also generated in a chain every time iron ions are dividedly added.

(8) OH radicals are also generated by the following third and fourth. That is, other than the Fenton main reaction of (6) above, it continues to be efficiently generated by incidental, secondary, and chain reactions.
Thirdly, OH radicals generated by the reaction formula of the chemical formula 3 react with water such as the water to be treated 3 by the reaction formulas of the chemical formulas 7 and 8 to form new OH radicals in a chain. Generated repeatedly.
Fourthly, the trivalent iron ion generated by the reaction formula of Chemical Formula 3 (Chemical Formula 1) and hydrogen peroxide react by the reaction formula of Chemical Formula 11 (Chemical Formula 9 and Chemical Formula 10). New OH radicals are repeatedly generated in a chain.
Note that the generation of the first, second, third, and fourth OH radicals ends when the hydrogen peroxide of the Fenton reagent is exhausted in the processing tank 4.

(9) Now, a large amount of OH radicals are generated by such a chain reaction, and the OH radicals thus generated have an extremely strong oxidizing power.
Therefore, in the treatment tank 4, the organophosphorus pesticide 1 contained in the water to be treated 3 is oxidized and decomposed by the OH radicals, and thus is mineralized into a low molecular compound. Organophosphorus pesticides 1 such as phosphonomethylglycine, methamidophos, and parathion are organic compounds with large molecular weights that are difficult to separate, but low molecular weights such as water and carbon dioxide by chain addition of OH radicals and oxidation reactions. It becomes mineralized into a compound.

(10) In the water 3 to be treated, the organophosphorus pesticide 1 contained therein is mineralized in this way into water, carbon dioxide, and the like, and is discharged from the treatment tank 4 to the post-treatment tank 11. The illustrated post-treatment tank 11 includes a neutralization tank 12, a coagulation tank 13, a storage 14, a dehydration tank 15, a treatment water tank 16, a container 18, and the like.
Since hydrogen peroxide is effectively used without waste for the generation of OH radicals as described above, the remaining amount after the treatment is small, and the use of the neutralizing agent in the neutralization tank 12 is negligible or absent. . And the to-be-processed water 3 is adjusted to the state which can be drained by passing through the post-treatment tank 11, and is drained outside.

(11) In this treatment apparatus 2 and treatment method, as described above, the organophosphorus pesticide 1 contained in the water to be treated 3 is mineralized based on the treatment process or the like of the Fenton method. Realized.
That is, the amount of chemicals added such as hydrogen peroxide, divalent iron ions, and Fenton's reagent such as a pH adjuster is easily calculated from the theoretical reaction value, and is the same as or larger than the theoretical reaction value. Several times as much as the actual required amount is added, and thus the addition amount is optimized.
The treatment apparatus 2 is provided with a raw water tank 9 and a post-treatment tank 11 with a treatment tank 4 as the center, and a hydrogen peroxide addition means 6, an iron ion addition means 7, a pH adjustment means 8 and the like. It consists of the structure which was made. That is, in this processing method, the processing device 2 having a relatively simple configuration is used, and stable processing is possible.
The operation of the present invention is as described above.

Next, examples of the present invention will be described.
First, regarding the processing apparatus 2 and the processing method of the present invention, the oxidation and decomposition processes of Example 1 will be described.
That is, with respect to the place described above entitled “Reaction in treatment tank 4 (oxidation and decomposition of organophosphorus pesticide 1)”, as Example 1 of the present invention, phosphonomethylglycine which is a representative example of organophosphorus pesticide 1 An example of the oxidation and decomposition process will be theoretically verified.
As shown in Example 1, phosphonomethylglycine (C ₃ H ₇ O ₅ NP) contained in the water to be treated 3 includes an organic structure of an intermediate in its oxidation and decomposition processes. Each reaction formula (formula 1 to formula 10) of the chain processes 1 to 10 shown in the following chemical formula 12, chemical formula 13, chemical formula 14, chemical formula 15, chemical formula 16, etc. is sequentially traced. In turn, OH radicals (.OH) are involved, and oxidation and addition reactions proceed. At the same time, water, carbon dioxide, oxygen, and other low-molecular compounds are derived, generated, liberated, and decomposed and mineralized. End up.
The phosphate ion P (═O) (OH) ₂ (O) ⁻ generated in the reaction formula (Formula 7) of the process 7 of the following chemical formula 15 is converted into a complex and coprecipitated, that is, coagulated, precipitated, and removed. The Then, in the reaction formula (Formula 10) of the process 10 of the following chemical formula 16, nitric acid (HNO ₃ ) is finally generated.
In the reaction formula of the process 10 (Formula 10), first, hydrogen radicals (H ⁺ + e ⁻ ) that are nascent hydrogen atoms are generated by oxidative decomposition of water by OH radicals, and residues are generated in the hydrogen radicals. Is reduced to nitric acid. Moreover, in the reaction formula of each process, the chemical formula was described in the upper stage, and the structural formula was described in the lower stage.

The chemical formula 17 is a general reaction formula of the reaction formulas (formula 1 to formula 10) of the chain processes 1 to 10 shown in the chemical formulas 12 to 16.
As shown in the general reaction formula of this chemical formula 17, theoretically, 1 mol of phosphonomethylglycine is co-precipitated with 3 mol of carbon dioxide, 1 mol of nitric acid and 22 mol of OH radical. It is decomposed and mineralized into 1 mol of phosphate ion, 0.5 mol of oxygen and 13 mol of water.
The OH radicals may be prepared in 22 mol as the theoretical reaction value, but the actual required amount is prepared several times as much. The same applies to hydrogen peroxide, divalent iron ions, and the like, which are OH radical products.
In this way, phosphonomethylglycine is oxidized and decomposed.

By the way, although the above-mentioned phosphonomethylglycine is widely known as a herbicide for the organophosphorus pesticide 1, in view of its poor water solubility in its use, the surfactant dioxane (1, 4) is generally used. Dioxane). The composition ratio is 48% to 52%, for example.
Dioxane also follows the reaction formulas of the chain processes 1 to 3 shown in the following chemical formulas 18 and 19 (formulas 1 to 3), whereby OH radicals are sequentially involved and oxidized and added, and carbon dioxide. It is decomposed and mineralized into carbon, oxygen, water, etc. For the upper and lower two lines of the reaction formula for each process, refer to the previous section.

The above chemical formula 20 is a general reaction formula of the reaction formulas (formula 1 to formula 3) of the chain processes 1 to 3 of chemical formulas 18 and 19.
Theoretically, 1 mol of dioxane is decomposed and mineralized by 24 mol of OH radicals into 4 mol of carbon dioxide, 1 mol of oxygen, and 16 mol of water. For the relationship between the theoretical reaction value and the actual required amount, see above.
Dioxane is also oxidized and decomposed in this way.
About Example 1, it is as above.

Next, a second embodiment of the present invention will be described. That is, the experimental result of Example 2 is demonstrated regarding the processing apparatus 2 and the processing method of this invention.
In this experiment, treated water 3 containing fenitrothion (C ₉ H ₁₂ O ₅ NPS), which is an example of organophosphorus pesticide 1, is treated as sample 1-1 (raw water) at room temperature at treatment tank 4. Supplied to.
And each chemical | medical agent was added in predetermined order, changing the addition amount suitably for every sample 1-2, 1-3, 1-4, and 1-5. Sample 1-2 is a reference example in which only hydrogen peroxide is added, and Samples 1-3, 1-4, and 1-5 are examples processed by the Fenton method of the present invention.
The experimental procedure is as follows. That is, first, the treated water 3 is treated by the Fenton method or the like, and then the complex 17 is agglomerated, precipitated and removed by addition of PAC, and solid-liquid separation is performed (see the above-mentioned place regarding the post-treatment tank 11). The filtrated water 3 to be treated was used as an analysis object of the experiment and an evaluation object of the experiment result.
The test conditions are shown in Table 1 below. That is, the amount of each chemical added, such as hydrogen peroxide as a source of generation of OH radicals in the Fenton method, ferrous sulfate as a catalyst, sulfuric acid or caustic soda for pH adjustment, PAC for aggregation, etc. is shown in Table 1 below. As of.

When an experiment was performed under the above test conditions, the experimental results shown in Table 2 below were obtained.
That is, the content of fenitrothion contained in the water to be treated 3 to be analyzed, and other analysis items are the sample 1-1 before the Fenton treatment, the sample 1-2 of the reference example, and the sample 1 after the Fenton treatment. As a result of measuring each of −3, 1-4, and 1-5, the following experimental results in Table 2 were obtained.
The measurement and analysis methods for each analysis item are as follows.
・ PH: JIS K0102.12
・ TOC (total organic carbon)
: JIS K0102.22.1 (combustion oxidation-infrared TOC analysis method) (C conversion)
・ Fenithrion
: Gas chromatograph mass spectrometry / electric conductivity: JIS K0102.13.1 (electrode method)

From the experimental results shown in Table 2, the following points were confirmed in terms of data. That is, according to each example of Samples 1-3, 1-4, and 1-5 treated by the Fenton method of the present invention, fenitrothion that is an organophosphorus pesticide 1 is carbon dioxide, oxygen, water, It was confirmed and evaluated in terms of data that it was oxidized, decomposed and mineralized into nitric acid, sulfuric acid, etc., and almost disappeared in the water 3 to be treated.
This was supported by a decrease in the TOC data value and an increase in the electrical conductivity data value.
About Example 2, it is as above.

BRIEF DESCRIPTION OF THE DRAWINGS It is used for description of the best form for implementing invention about the processing apparatus and processing method of the organophosphorus agrochemical containing water which concern on this invention, and is a structure flowchart.

DESCRIPTION OF SYMBOLS 1 Organophosphorus pesticide 2 Treatment apparatus 3 Treated water 4 Treatment tank 5 Treated water supply means 6 Hydrogen peroxide addition means 7 Iron ion addition means 8 pH adjustment means 9 Raw water tank 10 pH adjustment tank 11 Post-treatment tank 12 Neutralization Tank 13 Coagulation tank 14 Storage tank 15 Dehydration tank 16 Treated water tank 17 Complex 18 Container

Claims (8)

A treatment device that oxidizes and decomposes organophosphorus pesticides contained in water to be treated based on the Fenton method,
The organophosphorus pesticide comprises an organic compound containing nitrogen and phosphorus, and the treatment apparatus includes a treatment tank, a treated water supply means attached to the treatment tank, a hydrogen peroxide addition means, and an iron ion addition means. , PH adjusting means,
The treated water supply means supplies the treated water containing the organophosphorus pesticide to the treatment tank, and the hydrogen peroxide addition means adds hydrogen peroxide to the treated water in the treatment tank. The iron ion addition means adds divalent iron ions to the water to be treated in the treatment tank,
The pH adjusting means adds a pH adjusting agent to the treated water supplied to the treated tank from the treated water supply means and the treated water supplied to the treated tank, and the treated water An apparatus for treating water containing organophosphorus pesticides, characterized in that is maintained at a predetermined weak acidity. 2. The treatment apparatus for water containing organophosphorus pesticides according to claim 1, wherein the hydrogen peroxide adding means adds a total amount of an aqueous solution of hydrogen peroxide at the beginning of the reaction, and the iron ion adding means adds hydrogen peroxide. Later, repeated multiple cycles intermittently, divalent iron ion solution was added in portions,
The pH adjusting means is characterized in that an acid pH adjuster is added before the addition of hydrogen peroxide, and an alkaline pH adjuster is added every time an iron ion solution is added after the addition of hydrogen peroxide. To treat water containing organophosphorus pesticides. The treatment apparatus for water containing organophosphorus pesticides according to claim 2, wherein the organophosphorus pesticide comprises fenitrothion, phosphonomethylglycine, methamidophos, methyl dimethone, dichlorvos, or parathion.
The iron ion adding means adds an aqueous solution of ferrous sulfate or ferrous chloride, and the pH adjusting means adds, for example, sulfuric acid or caustic soda, so that the water to be treated in the treatment tank is brought to about pH 4. An apparatus for treating water containing organophosphorus pesticides, characterized by maintaining and suppressing decomposition reaction of added hydrogen peroxide into water and oxygen. A treatment method for oxidizing and decomposing an organophosphorus pesticide contained in water to be treated based on a Fenton process, the organophosphorus pesticide comprising an organic compound containing nitrogen and phosphorus,
Hydrogen peroxide, a divalent iron ion solution, and a pH adjuster are added to the water to be treated containing the organophosphorus pesticide, and hydrogen peroxide is added in its entirety at the beginning of the reaction. The iron ion solution of is intermittently added in multiple cycles after the addition of hydrogen peroxide,
As for the pH adjuster, an acid pH adjuster is added before the addition of hydrogen peroxide, and after the addition of hydrogen peroxide, an alkaline pH adjuster is added for each divided addition of the divalent iron ion solution. A method for treating water containing organophosphorus pesticides, which comprises maintaining water at a predetermined weak acidity. 5. The method for treating organophosphorus pesticide-containing water according to claim 4, wherein the hydrogen peroxide added in whole amount is reduced with divalent iron ions added in a divided manner as a catalyst, and OH radicals are reduced. Generated
Thus, the organophosphorus pesticide-containing water is characterized in that the organophosphorus pesticide contained in the water to be treated is oxidized and decomposed by the OH radicals to be mineralized into a low molecular weight compound. Processing method. 6. The method for treating organophosphorus pesticide-containing water according to claim 5, wherein the hydroxide ions produced by the reduction reaction of hydrogen peroxide are trivalent produced by the oxidation reaction of divalent iron ions. Oxidized with iron ions to generate OH radicals,
Thus, the organophosphorus pesticide-containing water is characterized in that the organophosphorus pesticide contained in the water to be treated is oxidized and decomposed by the OH radicals to be mineralized into a low molecular weight compound. Processing method. The method for treating organophosphorus pesticide-containing water according to claim 5 or 6, wherein the produced OH radical further reacts with water such as the water to be treated to produce new OH radical and water. Is repeated in a chain,
Thus, treatment of water containing organophosphorus pesticides, characterized in that the organophosphorus pesticides are oxidized and decomposed and mineralized into low molecular weight compounds by OH radicals that are repeatedly generated in this manner. Method. 7. The method for treating organophosphorus pesticide-containing water according to claim 5 or 6, wherein the trivalent iron ions produced by the oxidation reaction of divalent iron ions react with hydrogen peroxide, so that at least new The reaction of generating OH radicals is repeated in a chain,
Thus, treatment of water containing organophosphorus pesticides, characterized in that the organophosphorus pesticides are oxidized and decomposed and mineralized into low molecular weight compounds by OH radicals that are repeatedly generated in this manner. Method.

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