JPH11319890A - Treatment of laundry waste water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a treating method of laundry waste water capable of suppressing the generation of secondary waste, easily disposing the generated waste, performing the treatment with continuous stability and high safety and making a treating device compact. SOLUTION: In a treating method for evaporating and condensing a laundry waste water or the like generated from, for example, a nuclear facility or the like and discharging the resultant condensed water, a foaming factor is removed and a part of COD component is oxidized and decomposed by adding hydrogen peroxide solution or ozone as an oxidizing agent to untreated waste water and irradiating with UV in an UV oxidation reactor 2. Though a problem that waste water untreated with irradiation of ultraviolet ray is vigorously foamed by being sent to a evaporation concentration vessel 3 to be evaporated and concentrated and a part of the COD component and a radioactive nuclide are moved to the condensation liquid side to be released to the environment is conventionally generated, the waste water treated with ultraviolet oxidation is not foamed even at the time of being concentrated at least up to 500 times.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating laundry waste liquid, and more particularly, to a method for treating a laundry waste liquid and a hand wash waste liquid generated in a nuclear facility or the like to a level that can be discharged to the environment.

[0002]

2. Description of the Related Art Freon has been used as a conventional dry-cleaning type cleaning agent, which causes environmental pollution. For example, in a nuclear facility such as a nuclear power plant, the washing method is dry cleaning. From water washing. Laundry wastewater and handwashing waste liquid containing a small amount of radioactivity can be released to the environment as it is, and the radioactivity concentration and C
The OD component violates the release criteria. Therefore, assuming release into the environment, it is necessary to remove the COD component and the BOD component in addition to the removal of the trace radioactivity. At present, activated carbon treatment is often performed to minimize the release of surfactants, which are the main components of the COD component and the BOD component in the waste liquid, into the environment. However, a large amount of secondary waste of the used activated carbon is generated, and the water content of the used activated carbon is high, which makes it difficult to perform incineration.

On the other hand, washing waste liquid and hand washing waste liquid are evaporated and concentrated to separate into condensed water and concentrated water, and the COD and the radioactivity concentration of the condensed water are reduced to the emission standard value and released to the environment, while the concentrated liquid is solidified. Methods have also been adopted. In this case, if the washing waste liquid and the hand washing waste liquid are directly evaporated and concentrated, foaming occurs vigorously during the concentration treatment, and a problem arises in that a high-concentration COD component or a radionuclide is transferred as a droplet to a condensed water system. At present, as a pretreatment, foaming components are reduced by activated carbon and a coagulant as a pretreatment, and evaporation and concentration are performed.
However, when a coagulant is used, there is a problem that a large amount of secondary waste is generated. As described above, regarding the method of treating the washing waste liquid in a nuclear facility such as a nuclear power plant,
There is a demand for the development of a treatment method that minimizes not only the radioactive component but also the COD component and the BOD component, enables release to the environment, and reduces the amount of secondary waste generated.

[0004] A known technique is a method of oxidatively decomposing organic substances with ultraviolet (UV) irradiation and aqueous hydrogen peroxide or ozone. However, this known processing method aims at thoroughly decomposing organic substances, and no attempt has been made at all to remove foaming factors. For example,
In "The feasibility of a Landry wastewater treatment method using ultraviolet light and ozone" (Abstracts of the Atomic Energy Society of Japan "1997 Spring Annual Meeting"), organic matter contained in washing wastewater and handwash wastewater in a nuclear power plant was analyzed using ultraviolet light and ozone. Although a technique for decomposing the solution is disclosed, only the reduction of the TOC concentration is pursued here, but no description is made on how to treat this processing solution. "Ozone /
Oxidative Decomposition of Organic Substances Using UV Light "(Chemical Engineering Society No. 6
The technology disclosed in the 2nd Annual Meeting (1997), also pursues only the reduction of the TOC concentration, and does not refer to foaming during evaporation and concentration.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and is directed to a processing method for processing a washing waste liquid so as to have a water quality that can be discharged into the environment or reused. The generation of secondary waste can be suppressed, and the generated secondary waste can be easily disposed of.
It is an object of the present invention to provide a method for treating laundry waste liquid, which can perform treatment with continuous stability and high safety, and can further reduce the size of the treatment device.

[0006]

According to the first aspect of the present invention, there is provided a washing and washing step including an evaporating and condensing step of heating and concentrating washing waste liquid and condensing an evaporative component to separate the washing waste liquid into a concentrated liquid and a condensed liquid. In the method for treating a waste liquid, an ultraviolet treatment step of irradiating a laundry waste liquid to which hydrogen peroxide water and / or ozone is added as an oxidizing agent with an ultraviolet ray is added before the evaporative concentration step. .

According to a second aspect of the present invention, in the first aspect, the enrichment ratio in the evaporative concentration step is 100 to 50.
It is characterized in that it is set to 0 times.

According to a third aspect of the present invention, in the first or second aspect of the present invention, of the concentrated liquid and the condensed liquid obtained in the evaporating and condensing step, the concentrated liquid is solidified, and the condensed liquid is exposed to the environment. It is characterized by being released or reused.

A fourth aspect of the present invention is the method according to any one of the first to third aspects, wherein the processing speed of the washing waste liquid in the ultraviolet treatment step is set to 10 m ³ / h / kW or less. .

According to a fifth aspect of the present invention, in the first aspect of the present invention, the main wavelength of the ultraviolet ray used in the ultraviolet ray treatment step is 253.7 nm or 184.9 nm.
It is characterized by the following.

The invention of claim 6 is characterized in that, in the invention of any one of claims 1 to 5, a filtration step of filtering washing waste liquid is added before the ultraviolet treatment step.

According to a seventh aspect of the present invention, in the first aspect of the present invention, the amount of the oxidizing agent added in the ultraviolet acid treatment step is determined by the number of moles of carbon determined from the total organic carbon concentration of the washing waste liquid. It is characterized in that the amount is at least 0.3 times the molar amount of the above.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION In the treatment method of the present invention, an aqueous solution of hydrogen peroxide or ozone as an oxidizing agent is added to a washing waste liquid, a hand washing waste liquid, or a mixed waste liquid thereof, and the mixture is irradiated with ultraviolet rays. In addition to desorbing the foaming factor contained in, a part of the TOC component is oxidatively decomposed. Conventionally, when waste liquid not subjected to ultraviolet oxidation treatment is sent to an evaporator and concentrated, foaming occurs violently during evaporation and concentration, and some T
There is a problem that the OC component and the radionuclide migrate to the condensed liquid side from which the environment is released. However, the waste liquid that has been subjected to the ultraviolet oxidation treatment by the treatment method of the present invention does not foam even if it is concentrated at least 500 times.

FIG. 1 is a diagram showing an example of the configuration of a processing system to which a method for processing waste laundry according to the present invention is applied. FIG.
, 1 is a filter, 2 is an ultraviolet (UV) oxidation reactor, 2a is an ultraviolet (UV) lamp, and 3 is an evaporator. The filter 1 has a function of removing lint or dirt such as clothes contained in the washing waste liquid and the hand washing waste liquid, thereby preventing the surface of the ultraviolet lamp from being stained. In addition, as this filter 1, it is preferable to use what can collect | recover the particle of 10-100 micrometers. UV
The oxidation reactor 2 has a function of desorbing the foaming factor and decomposing the COD component, and has a function of suppressing the propagation of various bacteria. The evaporative concentrator 3 concentrates the residual COD components and radionuclides of the processing waste liquid and separates them into concentrated water and condensed water. The obtained condensate (recovered liquid) is reused or released to the environment, while the concentrated liquid containing high-concentration COD and radionuclide is solidified with cement or the like.

In the present invention, the main wavelength of the ultraviolet light irradiated by the ultraviolet irradiation lamp is 253.7 nm,
Or 184.9 nm (more preferably 253.7 n
It is particularly effective to use light having a wavelength of m). Further, in the present invention, since it is only necessary to remove a part of the foaming factor of the TOC component, the processing can be performed at a processing speed approximately six times as high as the processing speed when the TOC is decomposed by 90% or more.

An embodiment of the processing method of the present invention will be described below. (Example 1) In this example, a simulated washing waste liquid
, And then a concentrated foaming test was performed. FIG. 2 shows an example of a diagram of the UV oxidation reaction apparatus used in this example. In FIG. 2, 11 is a power supply box, 12 is an ultraviolet (UV) reactor, 12a is an ultraviolet (UV) lamp,
13 is a circulation pump, 14 is a circulation flow meter, 15 is a cooler,
Reference numeral 16 denotes a simulated washing waste liquid tank, 17 denotes a hydrogen peroxide water supply pump, and 18 denotes a hydrogen peroxide water meter. Also in FIG.
FIG. 1 shows a schematic configuration diagram of a concentration foaming test apparatus used in this example. In FIG. 3, 21 is a replenishing liquid container, 22 is a rubber stopper,
23 is a scale, 24 is a foaming tower, 25 is a thermocouple protection tube,
26 is a waste liquid, 27 is a mantle heater, 28 is a cooler, 2
Reference numeral 9 denotes a measuring cylinder, 30 denotes a temperature recorder, 31 denotes an A / V meter, and 32 denotes a slide rack. Mantle heater 27
Has a power supply of 100 V and a power amount of 400 W, an effective length of 400 mm, a tower diameter of 55 φ, and a tower length of 1000.
mm, the material of the tower is Pyrex.
Is silicone rubber.

The processing test method according to this embodiment will be described below. First, the simulated washing waste liquid 16 prepared as shown in FIG. 2 is filled with the prepared simulated washing waste liquid 20 L, and then the filled simulated washing waste liquid is sent to the ultraviolet reactor 12 using the circulation pump 13. Note that, as the simulated washing waste liquid in the present embodiment, a washing liquid obtained by putting a detergent, worn clothes, and water into a home washing machine and washing the used washing liquid is used. As the detergent in this example, sodium linear alkylbenzene sulfonate,
A material containing sodium alkyl sulfate, sulfate, aluminosilicate, enzyme, fluorescent agent and the like as components is used.

After the inside of the ultraviolet reactor 12 is filled with the simulated washing waste liquid, the ultraviolet lamp 12a of 2 kW is turned on, and at the same time, the hydrogen peroxide water supply pump 17 is operated to supply hydrogen peroxide (35%) to 13%. It is sent to the simulated washing waste liquid tank 16 at a flow rate of 0.7 ml / h. The mixture of the hydrogen peroxide solution and the simulated washing waste liquid is circulated by the circulation pump 13 and is oxidatively decomposed in the ultraviolet reactor 12. This oxidative decomposition treatment
After 0 minutes, the simulated washing waste liquid in the simulated washing waste tank 16 and the ultraviolet reactor 12 is extracted.

Next, 500 ml of the simulated washing waste liquid extracted
Is packed in the foaming tower 24 of the concentration foaming test apparatus shown in FIG. Then, the power of the mantle heater 27 is turned on, and the simulated washing waste liquid is heated and evaporated. The evaporation rate at this time is 1
Set to 60 ml / h. The evaporation generated by boiling is introduced into the cooler 28 and condensed. The condensed liquid obtained is guided to the measuring cylinder 29, and the amount of evaporation at each time is measured. If the simulated washing waste liquid foams by heating, it is observed in the foaming tower. The height at which the foam rises at that time is measured on a scale. The simulated washing waste liquid that evaporates is constantly replenished.

FIG. 4 shows the results of the concentrated foaming test. As shown in FIG. 4, in the simulated laundry waste liquid not subjected to the ultraviolet treatment, the temperature of the waste liquid reached the boiling point of water by heating, and at the same time, the foaming of the waste liquid started, and overflowed the foaming tower immediately. Here, the foam height of 80 cm indicates the top of the scale. On the other hand, the simulated washing waste liquid subjected to the ultraviolet treatment for 30 minutes is 1
Foaming did not occur at all even after the concentration of 00 times.

Table 1 shows the properties of each solution obtained in this test.
Shown in

[0022]

[Table 1]

The TOC and COD of the condensate (distillate) are 5p
pm, which was a value that could be released to the environment. Also, p
H was also 7.8 and could be released as it was without adjusting the pH.

Example 2 In this example, a simulated washing waste liquid was irradiated with ultraviolet rays for 3 hours, and then a concentration foaming test was carried out. In this embodiment, the simulated washing waste liquid prepared in the same manner as in Embodiment 1 was subjected to ultraviolet treatment for 3 hours by the test apparatus used in Embodiment 1, and concentrated to 500 times. FIG. 5 shows the results of the concentration foaming test. As in Example 1, the untreated liquid boiled and violently foamed at the same time as the untreated liquid, but the foam that had been subjected to the ultraviolet treatment for 3 hours did not show any foaming even when concentrated to 500 times.

Table 2 shows a property analysis table of each liquid obtained in this test.
Shown in

[0026]

[Table 2]

The TOC and COD values of the condensate (distillate) were around 1 ppm, which was even lower than in Example 1. That is, a value that can sufficiently clear the release standard was obtained.

It is considered that the phenomenon that the foaming is suppressed by performing the ultraviolet oxidation treatment is obtained by the initial detachment or cutting of the component that causes the foaming. As one of the mechanisms, elimination of the sulfone group of sodium linear alkylbenzene sulfonate contained in the detergent is considered. FIG. 6 shows the change over time of the sulfate ion and the chlorine ion with respect to the ultraviolet irradiation time. As shown in FIG. 6, desorption of sulfate ions has started at the same time as irradiation with ultraviolet light. This trend is consistent with the foaming situation.

Example 3 In this example, a simulated hand washing waste liquid was irradiated with ultraviolet rays for 3 hours, and then a concentration foaming test was carried out. As the simulated hand washing waste liquid, a hand washing detergent (main component: potash coconut oil, isopropyl methyl phenol) was added to 20 L of water in a predetermined amount, and the liquid was used by 30 persons for washing their hands. A concentration foaming test was performed using the simulated hand washing waste liquid under the same conditions as in Example 2. FIG. 7 shows the results of the concentration foaming test. In the untreated liquid, foaming occurred intensely at the same time as the boiling, but the foam treated with the ultraviolet ray for 3 hours did not show any foaming even when concentrated to 500 times.

Table 3 shows the property analysis table of each liquid obtained in this test.
Shown in

[0031]

[Table 3]

As a result, the simulated hand washing waste liquid showed almost the same tendency as the simulated washing waste liquid.

(Embodiment 4) In this embodiment, actual washing waste liquid
After irradiating with UV for a period of time, a concentration foaming test was performed. The actual washing waste liquid is obtained by actually washing clothes worked in a nuclear power plant with an existing washing machine, using the same detergent as the simulated washing liquid. In this example, the UV oxidizing apparatus used for the simulated washing waste liquid was brought into a nuclear power plant, and a concentration foaming test was performed using actual washing waste liquid. The test conditions were in accordance with the example of the simulated washing waste liquid. FIG. 8 shows the results of the concentration foaming test. The untreated liquid generated intense foaming at the same time as boiling.
Foaming was not observed at all even when concentrated to 00 times.

Table 4 shows the properties of each solution obtained in this test.
Shown in

[0035]

[Table 4]

As a result, the TOC of the condensate (distillate) is 1
ppm and COD was below the measurement limit.
From this, it was confirmed that the environmental discharge of the condensate was sufficiently possible.

Example 5 In this example, a concentrated foaming test was performed after irradiating the simulated washing waste liquid with ultraviolet light for 3 hours using ozone as an oxidizing agent. In this example, a simulated washing waste liquid (TO) prepared in the same manner as in Example 2 was used.
C; 178 ppm), and at the same time, 0.75 O ₃ Nl / h of ozone was supplied thereto, and at the same time, ultraviolet rays having a wavelength of 254 nm were irradiated. As shown in FIG. 2, the ozone was introduced by blowing from the lower part of the ultraviolet reactor 12.

The simulated washing waste liquid is composed of 20 g of detergent and 30 tap water.
Laundry (wearing work clothes) 2 by washing liquid mixed with L
kg was obtained by washing. Take 650 ml of this simulated washing waste liquid and supply 254 nm with a mercury lamp while sending in ozone.
An oxidation treatment was performed by irradiating ultraviolet rays having a wavelength. At this time, the ozone feed rate was 0.75 O ₃ Nl / h, and the oxidation treatment time was 3 hours. By this treatment, the TOC of the simulated washing waste liquid was reduced from 178 ppm to 53 ppm.

Next, 600 ml of the simulated washing waste liquid subjected to the above-mentioned oxidation treatment was taken, and a concentration foaming test was conducted in the same manner as in Example 1. The concentration ratio was 100 times, and 594 ml of a condensate (distillate) and 6 ml of a concentrate were obtained. At this time, no foaming was observed.

As described above, in the present invention, the amount of the oxidizing agent added to the washing waste liquid, the hand washing waste liquid or a mixture thereof is as follows.
About 1/6 of the amount capable of decomposing 90% of the TOC is sufficient. By treating the waste liquid to which such a small amount of the oxidizing agent is added with ultraviolet irradiation, even if it is concentrated 500 times, foaming does not occur. Was found. The present invention is also applicable to the treatment of surfactants generated from the general industry and the general household, and it is highly likely that adoption of this method is desired as environmental regulations become stronger in the future.

[0041]

As is apparent from the above description, according to the present invention, it is possible to suppress the foaming phenomenon at the time of evaporation and concentration by adding an oxidizing agent to the washing waste liquid and performing the ultraviolet oxidation treatment. In addition, it is possible to prevent the COD component and the radionuclide component from being transferred to the condensate due to foaming, and it is possible to perform highly reliable processing of the washing waste liquid. In addition, since there is no need to use coagulants, activated carbon, etc., there is no secondary waste generated, and reasonable treatment can be performed.
High safety because waste liquid treatment is possible under normal pressure conditions.
In order to suppress foaming, it is only necessary to desorb some foaming factors of the COD and TOC components, so that running costs and equipment costs can be significantly reduced. Further, since the COD and TOC concentrations are reduced, the amount of solidification processing on the concentration side after concentration and evaporation can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a processing system to which a method for treating waste laundry according to the present invention is applied.

FIG. 2 is a diagram showing a diagram of a UV oxidation reaction apparatus used in an example of the present invention.

FIG. 3 is a schematic configuration diagram of a concentrated foaming test apparatus used in an example of the present invention.

FIG. 4 is a view showing the results of a concentration foaming test in Example 1.

FIG. 5 is a view showing the results of a concentration foaming test in Example 2.

FIG. 6 is a diagram showing an example of a change over time of sulfate ions during ultraviolet irradiation.

FIG. 7 is a diagram showing the results of a concentration foaming test in Example 3.

FIG. 8 is a diagram showing the results of a concentration foaming test in Example 4.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Filter, 2 ... Ultraviolet (UV) oxidation reactor, 2a ... Ultraviolet (UV) lamp, 3 ... Evaporation concentrator, 11 ... Power supply box,
12 ... ultraviolet (UV) reactor, 12a ... ultraviolet (UV)
Lamp, 13: Circulating pump, 14: Circulating flow meter, 15 ...
Cooler, 16: Simulated washing waste liquid tank, 17: Hydrogen peroxide water supply pump, 18: Hydrogen peroxide water meter, 21: Replenishing liquid container, 22: Rubber stopper, 23: Scale, 24: Foaming tower, 25 ... Thermocouple protection tube, 26 ... waste liquid, 27 ... mantle heater, 28 ... cooler, 29 ... graduated cylinder, 30 ... temperature recorder, 31 ... A / V meter, 32 ... sliding slider.

Continued on the front page (51) Int.Cl. ⁶ Identification code FI C02F 1/32 C02F 1/32 1/72 101 1/72 101 1/78 ZAB 1/78 ZAB G21F 9/08 511 G21F 9/08 511B ( 72) Inventor Satoshi Miyamoto 2-3-1 Minatomirai, Nishi-ku, Yokohama-shi, Kanagawa Prefecture, Japan 1-72 JGC Corporation (72) Inventor Kazumi Kawamura 3-7-1, Ichibancho, Aoba-ku, Sendai, Miyagi Prefecture Tohoku Electric Power Co., Inc. (72) Inventor Yuji Yamazaki 3-7-1 Ichibancho, Aoba-ku, Sendai City, Miyagi Prefecture Tohoku Electric Power Co., Inc. (72) Inventor Hideyuki Ito Maeda No. 1 Tsukahama, Onagawa-cho, Oshika-gun, Miyagi Tohoku Electric Power Co., Inc.

Claims (7)

[Claims] 1. A method for treating laundry waste liquid, comprising the step of evaporating and concentrating the laundry waste liquid by heating and condensing an evaporative component, thereby separating the laundry waste liquid into a concentrate and a condensate. A method for treating laundry waste liquid, wherein an ultraviolet treatment step of irradiating ultraviolet light to the laundry waste liquid to which hydrogen water and / or ozone has been added is added before the evaporative concentration step. 2. The method according to claim 1, wherein the concentration ratio in the evaporative concentration step is 1
2. The method for treating a washing waste liquid according to claim 1, wherein the washing waste liquid is set to 00 to 500 times. 3. The method according to claim 1, wherein, of the concentrate and the condensate obtained in the evaporative concentration step, the concentrate is solidified, and the condensate is discharged or reused in the environment. 2. The method for treating waste laundry liquid according to 2. 4. The method for treating a laundry waste liquid according to claim 1, wherein the processing speed of the laundry waste liquid in the ultraviolet treatment step is set to 10 m ³ / h / kW or less. 5. The method for treating laundry waste liquid according to claim 1, wherein the main wavelength of the ultraviolet light used in the ultraviolet light treatment step is 253.7 nm or 184.9 nm. 6. The method according to claim 1, further comprising a step of filtering the washing waste liquid before the ultraviolet treatment step. 7. The method according to claim 1, wherein the amount of the oxidizing agent added in the ultraviolet treatment step is at least 0.3 times the molar number of carbon determined from the total organic carbon concentration of the washing waste liquid. 6. The method for treating a washing waste liquid according to any one of 6.