JP2001121164A - Method for treating sewage containing internal secretion disturbing substance or carcinogenic substance and apparatus for treating the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for stably treating various kinds of the internal secretion disturbing substances or carcinogenic substances, such as, for example, dioxin, bisphenol-A, dioxane and di(2-ethylhexyl) phthalate, existing in water. SOLUTION: The method for treating the sewage containing the internal secretion disturbing substances and/or carcinogenic substance consists in taking effluent out of the upper section of an ozone reaction chamber, refluxing the effluent to the lower section of the ozone reaction chamber, subjecting the effluent to irradiation with UV rays and gaseous ozone injection in a flow passage from the outflow to the reflux, adding raw water thereto in the flow passage for injecting the gaseous ozone and recovering the treated water from the upper section of the ozone reaction chamber. Hydrogen peroxide is recommended to be further injected into the water in the flow passage toward the irradiation with the UV rays or the gaseous ozone injection.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an endocrine disruptor,
More specifically, the present invention relates to a method for treating sewage containing carcinogens and the like, and more specifically, a method for treating sewage discharged from leachate and industrial wastewater at final disposal sites and containing endocrine disrupting substances and carcinogens. About.

[0002]

2. Description of the Related Art An endocrine disrupting chemical substance is a chemical substance that, when taken into the body of an animal, adversely affects the normal hormonal action performed in the living body. It has been pointed out that exposure to endocrine disrupting chemicals disrupts endocrine effects in humans and wild animals, and may cause reproductive dysfunction and malignant tumors. Endocrine disruptors act at very low concentrations. It has a serious effect on developmental stages such as fetal life,
It has also been pointed out that the effects may appear after growth. For this reason, there is a concern that it may have a serious impact on the survival of living organisms.

[0003] Carcinogenic substances are known to promote cell carcinogenesis. Some of the suspected endocrine disruptors and carcinogens from previous studies include:
PCBs, dioxins, polybrominated biphenyls, hexachlorobenzene, pentachlorophenol, 2,4,
5-trichlorophenoxyacetic acid, 2,4-dichlorophenoxyacetic acid, amitrol, atrazine, simazine, hexachlorocyclohexane, ethyl parathion, carbaryl, chlordane, 1,2-dibromo-3-chloropropane, DDT and its metabolites (DDE, DDD) ),
Kelsen, aldrin, endrin, dieldrin, endosulfan, heptachlor and heptachlor epoxide, malathion, mesomil, methoxychlor, Mailex, nitrophen, toxaphen, camfechlor, organic tin (such as tributyltin), trifluralin, alkylphenols, bisphenol A, diphthalic acid (2-ethylhexyl), butylbenzyl phthalate, dibutyl phthalate, dicyclohexyl phthalate, diethyl phthalate, benzo (a) pyrene, cadmium,
Lead, mercury, 2,4-dichlorophenol, adipic acid (2-ethylhexyl), benzophenone, 4-nitrotoluene, dioxane and the like are mentioned.

These include flame retardants, bactericides, insecticides, antifouling materials, corrosion inhibitors, heat carriers, preservatives, herbicides, respectively.
It is produced and used as a resin hardener, resin raw material, plastic plasticizer, solvent and the like. Alternatively, it is generated in the process of burning organic matter. The substance thus generated varies depending on the item, but is detected in environmental water at a concentration of approximately μ (micron) g / liter to p (pico) g / liter. Such concentration levels are COD, T
M (milli) g / of organic matter concentration in water estimated from OC etc.
It is very low compared to the liter order. However, these endocrine disrupting chemicals cause such effects in very small amounts. There is a demand for the development of a technology for removing even a trace amount of water from environmental water or water before being released into the environment. Taking leachate from landfills as an example, it contains various types of endocrine disruptors and carcinogens. The concentration is also high. Removal from these locations is an urgent task. As a conventional technique for treating a biologically hardly decomposable organic substance, for example, there is a method of performing a photochemical reaction such as ultraviolet rays and ozone. For example, a method is known in which active oxygen such as a hydroxy radical is generated once and then attacked. In that case, there is an excellent method using an ultraviolet lamp or a diffuser.

[0005]

However, wastewater containing endocrine disrupting substances and / or carcinogenic substances has a high inorganic ion concentration. When an ultraviolet lamp or an air diffuser is used, inorganic ions contaminate the surface of the protective tube of the ultraviolet lamp, or cause clogging of the air diffuser, thereby causing a troublesome problem that processing becomes unstable. Therefore, the present invention provides a method for stably treating various endocrine disrupting substances and / or carcinogenic substances present in water, such as dioxin, bisphenol A, dioxane, di (2-ethylhexyl) phthalate, and the like. That is.

[0006]

The present invention has solved the above-mentioned problems by the following means. (1) In a method for treating sewage containing endocrine disrupting substances and / or carcinogenic substances, the effluent is taken out from the upper part of the ozone reaction tank and refluxed to the lower part of the ozone reaction tank, and the effluent is discharged to reflux. A method for treating sewage, comprising: irradiating ultraviolet rays and injecting ozone gas in a channel, adding raw water in a channel into which ozone gas is injected, and collecting treated water from an upper part of the ozone reaction tank. (2) The method for treating sewage according to (1), wherein hydrogen peroxide is further injected in a flow path toward ultraviolet irradiation or ozone gas injection. (3) In the ultraviolet irradiation, an ultraviolet reaction tank is provided in the flow path, and the effluent flowing out of the ozone reaction tank flows down along the inner surface of the ultraviolet reaction tank in a film form. The method for treating sewage according to the above (1) or (2), wherein the method is carried out by irradiating the sewage. (4) In a treatment apparatus for treating sewage containing endocrine disrupting substances and / or carcinogenic substances, an outflow passage extending from the upper part of the ozone reaction tank and returning to the lower part of the ozone reaction tank is provided, and an ultraviolet ray reaction is provided in the middle of the outflow path. A sewage treatment apparatus comprising a tank, an ozone gas injection ejector, a raw water addition port in a flow path toward the ejector, and a treated water discharge path in an upper part of the ozone reaction tank. (5) The sewage treatment apparatus according to (4), wherein the inlet to the ultraviolet reactor is provided at a position higher than the height of the ozone reactor outlet. In the present invention, endocrine disrupting substances or carcinogenic substances are stably decomposed by the following actions. Endocrine disrupting substances or carcinogenic substances are rendered harmless by the oxidizing action of OH (hydroxy cation) generated by the reaction with ozone, hydrogen peroxide and ultraviolet rays, and the dechlorinating action of ultraviolet rays. The raw water and the ozone gas are brought into parallel contact with each other, so that the relatively high-concentration organic matter and the ozone gas are efficiently contacted, and the reaction efficiency is improved.

[0007]

Embodiments of the present invention will be described below. FIG. 1 is a conceptual diagram showing one embodiment of the present invention. An ozone reaction tank 1 having a body length is provided in the vertical direction, and an ultraviolet reaction tank 2 is provided in the vicinity thereof. The ozone reaction tank 1 has an outflow pipe 3 extending near the upper surface of the water, and the outflow pipe 3 is branched from the middle into one and the other. One branch pipe 4 communicates with the lower part of the ozone reaction tank 1, and the tip of the branch pipe 4 expands the jet port 5 downward in the ozone reaction tank to form a first flow path. In the first flow path, on the downstream side of the branch portion, the raw water addition port 6,
A hydrogen peroxide injection port 7, a water supply pump 8, and an ejector 9 are provided in this order, and the ejector 9 is provided with an ozone gas injection section 10. The other branch pipe 11 from which the outflow pipe 3 branches has a pumping pump 12 on the way and communicates with the inflow port of the ultraviolet reactor 2. The ultraviolet ray reaction tank 2 has a long ultraviolet lamp 13 extended vertically in the center of the inside thereof. The outer peripheral portion of the upper end has a height position higher than the water surface of the ozone reaction tank 1, and a gutter-shaped inflow pipe 14 surrounds the outer peripheral portion in a horizontal ring shape. The inflow port of the ultraviolet reaction tank 2 opens into the gutter-shaped inflow pipe 14, and when the inflow pipe 14 overflows, water remaining in the inflow pipe 14 is directed into the ultraviolet reaction tank 2 along the inner wall surface. Flow into a film. The lowermost end of the ultraviolet reaction tank 2 is formed in a mortar shape and the diameter thereof is reduced, and the outlet of the ultraviolet reaction tank 2 communicates with the lowermost lower end of the ozone reaction tank 1 also formed in a mortar shape. Thereby, a second flow path is formed which flows out of the upper part of the ozone reaction tank 1, communicates with the inner peripheral surface of the ultraviolet reaction tank 2, and enters the lower part of the ozone reaction tank 1 from the ultraviolet reaction tank 2. In the upper part of the ozone reaction tank 1, a treated pipe 15 is opened separately from the outflow pipe 3, and a waste ozone gas discharge port 16 is provided in the upper end. In addition, the baffle 24 provided in the upper part inside the ozone reaction tank 1 is for preventing air lock of each pump.

The effluent of the ozone reaction tank 1 taken out from the upper part of the ozone reaction tank 1 is passed through the ultraviolet reaction tank 2 and the ejector 9 to be returned to the lower part of the ozone reaction tank 1, while flowing into the ejector 9. Raw water is added to the water from the raw water addition port 6. Part of the water in the upper part of the ozone reaction tank 1 is obtained as treated water from the treated pipe 15. Hydrogen peroxide is added to the effluent from the ozone reactor 1, and ultraviolet rays are applied to the liquid falling film in the ultraviolet reactor 2. The effluent of the ultraviolet ray reaction tank 2 is introduced into the lowermost end of the ozone reaction tank 2, and the floating substance generated by the oxidation reaction of the inorganic substance in the raw water is not stored in the tank. That is, the treated water is recovered from the treated pipe 15 at the upper part of the ozone reaction tank 1 while adding the raw water from the raw water addition port 6 provided in the first flow path. During that time, the water pump 8 is driven to flow the water in the ozone reaction tank 1 through the first flow path, and hydrogen peroxide and ozone gas are injected. The pump 12 is driven to flow through the second flow path. Water in which hydrogen peroxide and ozone gas are mixed flows into the ultraviolet reactor 2 in a film form along the wall surface, and the ultraviolet lamp 13 emits light directly from a position where there is little influence of water droplets. Irradiate ultraviolet rays to water containing ozone gas. Excess ozone gas is discharged from the upper part of the ozone reaction tank 1 as waste ozone gas. As a light source for supplying ultraviolet rays in the ultraviolet reactor 2, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an excimer laser, or the like capable of irradiating ultraviolet rays having a relatively low wavelength in the range of 170 to 380 nm is provided. It would be fine. A protective tube may be used in combination with the light source to prevent damage to the ultraviolet lamp. As the material of the protective tube, quartz and synthetic quartz having a high ultraviolet transmittance of 170 to 380 nm are preferable.

A long ultraviolet lamp 1 in an ultraviolet reaction tank 2
As a method of installing the light source 3, there is a method in which the longitudinal direction of the ultraviolet lamps 13 is arranged vertically or horizontally with respect to the flow of water. The method of arranging in the direction is preferable because unevenness of the contact efficiency is reduced. As a method for injecting hydrogen peroxide, it is also possible to inject hydrogen peroxide from a plurality of locations. A plurality of ozone reactors 1 and ultraviolet reactors 2 may be provided. When providing a plurality, it is better to connect them in series rather than in parallel. In the configuration, the flow of water becomes a plug flow, and the processing is performed more reliably. In the above-described embodiment of the present invention, the raw water to be treated may be water before or after biologically decomposable organic matter is biologically removed from wastewater. The water may be either before or after the physicochemical removal of the physicochemically separable organic substance. It may be water before or after biologically removing the biologically separable organic matter. Activated sludge treatment, catalytic oxidation treatment, biofilm filtration treatment, anaerobic treatment, etc. are mentioned as methods of biologically removing organic matter from wastewater, and methods of physicochemical removal include sedimentation separation treatment, floating Separation treatment, membrane separation treatment, filtration treatment, coagulation sedimentation treatment, activated carbon treatment, electrodialysis and the like can be mentioned. In the above embodiments of the present invention, any of them can be preferably used. If water from which organic substances that can be separated biologically and physicochemically are removed is used as raw water to be treated, the treatment efficiency is increased. This is because the reaction between the hydroxyl radical and the endocrine disrupting substance and / or the carcinogenic substance is less likely to be inhibited by other coexisting organic substances. Hydroxy radicals efficiently act on the decomposition attack of endocrine disrupting substances and / or carcinogenic substances.

[0010] If the water before removal of biologically and physicochemically separable organic substances is used as raw water and the treatment according to the above embodiment of the present invention is carried out, the safety is enhanced. Organic matter remaining in the raw water is subsequently separated biologically or physicochemically. This is because harmful endocrine disrupting substances or carcinogenic substances are hardly contained in the sludge generated after the treatment. The ideal treatment conditions in the above embodiment of the present invention slightly vary depending on the properties of the raw water to be treated, for example, the concentrations of endocrine disrupting substances and / or carcinogens, COD concentration, and the like. When the total endocrine disrupting substance or carcinogen is 100 to 10,000 [pg / liter], the iron ion concentration is 0.5 to 5 [mg / liter], and the chloride ion concentration is 1,000 to 10,000 [mg / liter]. Examples are given below. The ozone injection rate is usually 10 to 100
[Mg / liter], preferably in the range of 20 to 50 [mg / liter]. The injection rate of hydrogen peroxide is 1 to 50, preferably 2 to 25 [mg / liter].
Should be selected from the range. When a low-pressure mercury lamp or a medium-pressure mercury lamp is used, the irradiation amount of the ultraviolet ray when combined with the ultraviolet ray is usually 0.1 to 5.0 [whr / liter], preferably 0.1 to 3.0 [whr / liter]. ]
Should be selected from the range. In the case of the falling film system, the water layer thickness is usually 0.2 to 5 [mm], preferably 0.3 to 3 [mm].
It is selected from the range of [mm].

[0011]

Hereinafter, specific examples of the present invention will be described.
The present invention is not limited to this. Example 1 Leachate from a landfill was treated as raw water using the treatment apparatus shown in FIG. The total amount of dioxins in raw water is 1000 [pg / liter], the concentration of iron and manganese is 1 [mg / liter], and the concentration of chloride ion is 500.
It was 0 [mg / liter]. -Ozone injection rate: 50 [mg / liter]-Hydrogen peroxide injection rate: 20 [mg / liter]-Ultraviolet lamp: medium pressure mercury lamp-Ultraviolet irradiation amount: 1.0 [Whr / liter]-Residence time: 30 [Min]-Circulation rate to ultraviolet reactor: 3 [-]-Circulation rate to ozone reactor: 3 [-] Operation was performed for one month under the above conditions. Table 1 shows the results one month after the operation. UV transmittance of the protective tube surface (254
nm) was exactly the same as in the initial stage, and no decrease in ultraviolet intensity due to the protective tube was observed. Also, the ozone absorption rate was exactly the same as the initial one, and no decrease in the ozone absorption rate was observed.

[0012]

[Table 1]

Comparative Example FIG. 5 is a diagram showing an outline of an apparatus formed as a comparative example. An apparatus as shown in FIG. 5 was assembled to treat sewage containing endocrine disrupting substances or carcinogenic substances. Members having the same purpose as the members shown in FIG. 1 are given the same reference numerals in principle. An ozone reaction tank 1 having a body length is erected, a raw water inlet 6 is formed at the lower part of the reaction tank 1 with a hydrogen peroxide inlet 7, and a treated water outlet 15 is provided at an upper part near the water surface. It is. An ozone gas diffusing port 20 communicating with an ozone gas source is provided at the bottom inside the reaction tank 1, and an ultraviolet lamp 13 is horizontally installed below the water surface. The outflow pipe 3 extends out of the tank from a position higher than the ultraviolet lamp, bends and descends, returns to a position lower than the height of the ultraviolet lamp 13, and a pump 8 is provided in the middle of the outflow pipe 3. Using such a device, it was operated for one month under the following conditions. Table 2 shows the results. The ultraviolet transmittance (254 nm) of the surface of the protective tube was reduced to 2% of the initial value. In addition, a brown scale was attached to the surface of the diffuser tube, and some pores were closed. The ozone absorption rate had dropped to the initial 95%. -Ozone injection rate: 50 [mg / liter]-Hydrogen peroxide injection rate: 20 [mg / liter]-Ultraviolet lamp: medium-pressure mercury lamp-Ultraviolet irradiation amount: 1.0 [Whr / liter]-Residence time: 30 [Min]

[0014]

[Table 2]

From these results, it was confirmed that the ultraviolet ray transmittance on the surface of the protective tube in the present invention was hardly reduced, and that the ultraviolet rays were stably supplied to the water to be treated. Further, it was recognized that there was almost no decrease in the ozone absorption rate, and that ozone was stably absorbed by the water to be treated. The reason why the dioxin treatment performance of the comparative example was low was that the treatment became unstable due to contamination of the protective tube and the diffuser tube.

[Embodiment 2] FIG. 2 is a diagram showing an outline of a second embodiment of the present invention. In this example, the ultraviolet reactor 2
Adopts a configuration in which the ultraviolet lamp 13 is immersed in water. The treated pipe 15 is not provided in a different direction from the outflow pipe 3, but is provided by branching from the other branch pipe 11 at an upstream portion of the ultraviolet reaction tank 1. A suction pump 21 is provided instead of the pump 12 on the way from the ultraviolet reactor 2 to the ozone reactor 1. Two ultraviolet reaction tanks 2 are provided in series, and an ultraviolet lamp 13 is provided at right angles to the flow direction in a tank filled with water to be treated. Inflow piping 14
Is not provided. The water to be treated is circulated by the suction pump 21 and the water supply pump 8, and the water to be treated is filled in the ultraviolet reactor 2. Others are the same as the embodiment of the present invention. Since the two ultraviolet reaction tanks 2 are connected in series, the processing becomes more reliable. Even in such a configuration, the effect of the present invention is not changed.

[Embodiment 3] FIG. 3 is a diagram showing an outline of a third embodiment of the present invention. In this example, a part of the circulating water is introduced into the ejector 9. The ultraviolet reactor 2 is configured to irradiate ultraviolet rays to the liquid falling film and is connected in series. The first flow path is provided with a bypass 22 on the way, and the bypass 22 is provided with the hydrogen peroxide inlet 7 and the ejector 9. Another hydrogen peroxide inlet 7 is
It is on the way to the ultraviolet reaction tank 2 in the first flow path. The treated pipe 15 is provided in the upstream outflow pipe 3 before reaching the branch portion. Others are the same as the embodiment of the present invention. In this way, the amount of circulating water and the amount of water introduced into the ejector 9 can be changed. Further, the ultraviolet treatment becomes more reliable. Even in such a configuration, the effect of the present invention is not changed.

[Embodiment 4] FIG. 4 is a diagram showing an outline of a fourth embodiment of the present invention. Part of the effluent from the ultraviolet reactor 2 is introduced into the ejector 9. As the ultraviolet reaction tank 2, those configured to irradiate the liquid falling film with ultraviolet light are connected in parallel. The outflow pipe 3 branches and one branch pipe 4 leads to one ultraviolet reaction tank 2, the other branch pipe 11 leads to another ultraviolet reaction tank 2, and the outlets of the respective ultraviolet reaction tanks 2 join downstream. , Refluxed to the lowermost end of the ozone reactor 1. Outflow pipe 3 refluxing at the lowermost end of ozone reactor 1
Forms a bypass 22 in a part of the downstream of the junction, has a water supply pump 8 and a hydrogen peroxide water inlet 7 in the bypass 22, and further arranges an ejector 9 for injecting ozone gas near the same place. Have. If the ultraviolet reactors 2 are connected in parallel, the water treatment load per ultraviolet reactor 2 can be reduced. Even in such a configuration, the effect of the present invention is not changed.

[0019]

According to the present invention having the above-mentioned constitution, it is possible to provide a method for stably treating various endocrine disrupting substances and / or carcinogenic substances present in water. By using the method for treating wastewater containing endocrine disrupting substances and / or carcinogenic substances, endocrine disrupting substances or carcinogenic substances in wastewater can be treated stably and safely. (1) The volume of the ultraviolet reaction tank can be made sufficiently small by separating it from the ozone reaction tank. If the volume is reduced, even when the protective tube of the UV lamp which is easily contaminated is cleaned with a chemical, the amount of the chemical used is only required to fill the small UV reaction tank. Cleaning can be performed with a small amount of chemicals used. (2) Ejectors usually do not have micropores like diffusers. If an ejector is used, poor air diffusion due to clogging does not occur. (3) If the liquid falling film is irradiated with ultraviolet light, the sewage does not come into contact with the ultraviolet light source or the protective tube that protects the ultraviolet light source.
These contaminations do not occur.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing one embodiment of the present invention.

FIG. 2 is a diagram showing an outline of a second embodiment of the present invention.

FIG. 3 is a diagram showing an outline of a third embodiment of the present invention.

FIG. 4 is a diagram showing an outline of a fourth embodiment of the present invention.

FIG. 5 is a diagram showing an outline of an apparatus formed as a comparative example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ozone reaction tank 2 Ultraviolet reaction tank 3 Outflow pipe 4 One branch pipe 5 Injection port 6 Raw water addition port 7 Hydrogen peroxide injection port 8 Water feed pump 9 Ejector 10 Ozone gas injection section 11 The other branch pipe 12 Pumping pump 13 Ultraviolet lamp 14 Inflow pipe 15 Treated pipe 16 Waste ozone gas outlet 20 Ozone gas diffuser 21 Suction pump 22 Detour 23 Protection pipe 24 Baffle plate

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Manabu Ikeguchi 11-1 Haneda Asahimachi, Ota-ku, Tokyo Ebara Corporation (72) Inventor Toshihiro Tanaka 4-2-1 Motofujisawa, Fujisawa-shi, Kanagawa Prefecture, Japan (72) Noboru Katsukura, Inventor No. 11-1 Haneda Asahimachi, Ota-ku, Tokyo Ebara Corporation (72) Inventor Mitsuru Imai 11-1, Haneda Asahimachi, Ota-ku, Tokyo Ebara Corporation Inside the factory (72) Inventor Koji Kosaka 11-1 Haneda Asahimachi, Ota-ku, Tokyo F-term in the Ebara Corporation (reference) 4D037 AA11 AA13 AB11 AB14 AB16 BA18 BB01 CA07 CA11 CA12 4D038 AA08 AB09 AB11 AB14 BA02 BA04 BA06 BB16 BB19 4D050 AA12 AA13 AB07 AB13 AB15 AB19 BB02 BB09 BC09 BD02 BD03 CA17

Claims (5)

[Claims] 1. A method for treating wastewater containing an endocrine disrupting substance and / or a carcinogenic substance, comprising taking out effluent from an upper part of an ozone reaction tank, refluxing the effluent to a lower part of the ozone reaction tank, and refluxing the effluent. Irradiating ultraviolet rays and injecting ozone gas in the flow path up to, adding raw water in the flow path injecting ozone gas, and collecting treated water from the upper part of the ozone reaction tank. 2. The method for treating sewage according to claim 1, wherein hydrogen peroxide is further injected in a flow path toward ultraviolet irradiation or ozone gas injection. 3. The ultraviolet irradiation is performed by providing an ultraviolet reaction tank in the flow path, causing effluent flowing out of the ozone reaction tank to flow down in a film form along the inner surface of the ultraviolet reaction tank, and from the center of the ultraviolet reaction tank. The method for treating sewage according to claim 1, wherein the irradiation is performed by irradiating the liquid onto a liquid falling film. 4. An apparatus for treating sewage containing endocrine disrupting substances and / or carcinogenic substances, wherein an outflow path extending from the upper part of the ozone reaction tank and refluxing to the lower part of the ozone reaction tank is provided. A wastewater treatment apparatus comprising an ultraviolet reaction tank, an ozone gas injection ejector, a raw water addition port in a flow path toward the ejector, and a treated water discharge path in an upper part of the ozone reaction tank. . 5. The sewage treatment apparatus according to claim 4, wherein the inlet to the ultraviolet reactor is higher than the outlet of the ozone reactor.