JPH06148391A - Equipment and method for treating liquid waste - Google Patents

Abstract

PURPOSE:To conduct stable concentrating treatment without lowering an evaporating treatment function, by a method wherein a liquid to be treated is subjected to the concentrating treatment while it is made to circulate through an activated carbon tower provided in liquid waste treating equipment, and a surfactant in the liquid to be treated is kept at low concentration. CONSTITUTION:Liquid waste containing a surfactant is supplied from a storage tank 9 to an evaporator 5 and heated to a prescribed temperature while it is made to circulate by a heating circulation system 8. As nonvolatile constituents such as salinity of the liquid to be treated in the evaporator 5 are concentrated, the surfactant contained in the liquid is also concentrated. The surfactant in the liquid to be treated is concentrated by evaporation in an activated carbon tower 1 and removed by adsorption. A monitor of a UV meter 3 is provided at an outlet of a circulation system of the activated carbon tower and thereby the concentration of the surfactant in the liquid is measured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waste liquid treatment apparatus for evaporating a waste liquid containing a surfactant and salt generated in a nuclear power plant facility, concentrating the salt content of a liquid to be treated, and collecting pure water. Regarding the method.

[0002]

2. Description of the Related Art In a nuclear power plant facility, waste liquid such as reclaimed waste water from a demineralizer, equipment drain and floor drain is generated. Since these waste liquids cannot be discharged directly to the outside of the power plant, they are treated by purifying them. The component of the waste liquid is sodium sulfate as a main component, and contains a clad, an ion exchange resin, a surfactant and the like. The current treatment method is a method of evaporating a waste liquid by an evaporator, concentrating non-volatile components such as salt, and condensing and collecting the evaporated water. The collected pure water will be reused as plant water. As the evaporation method, for example, a forced circulation type evaporator described in JP-A-62-68501 is used, and for example, film evaporation using a hydrophobic porous membrane described in JP-A-2-75387. Concentrators have been proposed.

[0003]

The method of evaporating and concentrating a waste liquid can recover highly pure condensed water even for a waste liquid containing a high concentration of salt. However, if the liquid to be treated contains a surfactant, various disadvantages due to the surfactant occur in the evaporative concentration of the waste liquid. That is, in the evaporator, the waste liquid boiling due to evaporation is vigorously foamed, and the generated foam overflows. Further, in the membrane evaporative concentrator, the hydrophobic porous membrane used is made hydrophilic, the concentrated liquid leaks, and the purity of the condensed water decreases.

Conventionally, a method has been used in which the liquid to be treated is pretreated to remove the surfactant and supplied to the evaporator. However, since the surfactant cannot be completely removed from the liquid to be treated, a small amount of the surfactant flows into the liquid to be treated supplied to the evaporator. As the concentration of the liquid to be treated increases due to the evaporative concentration of the waste liquid, there is a concern that the surfactant may cause various adverse effects.

An object of the present invention is to provide a waste liquid treatment apparatus capable of preventing various harmful effects caused by evaporative concentration of a waste liquid containing a surfactant.

[0006]

[Means for Solving the Problems] The above-mentioned object is to evaporate a waste liquid containing a surfactant and salt generated in a nuclear power plant facility, to concentrate the salt of a liquid to be treated, and to collect pure water. In the waste liquid treatment device, a system is provided to circulate the liquid to be treated vaporized in the evaporator of the device to the activated carbon tower, and the liquid to be treated is concentrated while being circulated to the activated carbon tower, and the surface activity of the liquid to be treated is increased. This is accomplished by keeping the agent at a low concentration.

[0007]

The waste liquid treatment apparatus of the present invention is provided with a system for circulating the liquid to be treated, which has been vaporized in the evaporator, to the activated carbon tower. The liquid to be treated is concentrated while being circulated through the activated carbon tower. Moisture is evaporated from the liquid to be treated supplied into the evaporator, and non-volatile components such as salt are concentrated. With the concentration of the liquid to be treated, the surfactant contained in the liquid to be treated is also concentrated. In the present invention, the liquid to be treated is circulated through the activated carbon tower. This is because it was found that the adsorption performance of the surfactant by the activated carbon does not deteriorate even in a high temperature range. Therefore, by circulating the high-temperature liquid to be treated through the activated carbon tower, the surfactant of the liquid to be treated is adsorbed and removed by the activated carbon. The amount adsorbed by activated carbon increases as the concentration of the adsorbent, the surfactant, increases. If the surfactant is concentrated by the evaporation treatment of the liquid to be treated, the removal of the surfactant by adsorption of activated carbon becomes easier. Therefore, in the present invention, the concentration of the surfactant in the liquid to be treated that has been vaporized in the evaporator can be maintained at a low concentration at all times, and various adverse effects caused by the evaporative concentration of the surfactant-containing waste liquid can be prevented. It can be prevented.

[0008]

EXAMPLES The present invention will be described below based on examples.
FIG. 1 shows a system diagram of an embodiment of the waste liquid treatment apparatus of the present invention. This apparatus supplies the liquid to be treated to a storage tank 9 for the liquid to be treated, an evaporator 5 for evaporating the liquid to be treated, an evaporator 5 and draws the liquid to be treated from a system 8 for heating and circulation, and an evaporator 5, and an activated carbon tower. 1
It is composed of a system 4 which circulates into the system 4, a condensed water recovery system 12 for recovering the vapor generated in the evaporator 5, and a storage tank 13 for storing the liquid to be treated concentrated in the evaporator 5. A circulation pump 6 and a heater 7 are provided in the heating circulation system 8 for the liquid to be treated.
A circulating system 4 to the activated carbon tower 1 includes an activated carbon tower 1 and a circulation pump 2
And a UV meter 3 are provided. The condensed water recovery system 12 is provided with a cooler 10 and a condensed water tank 11.

Next, the operation of the waste liquid treatment apparatus of the present invention will be described. The waste liquid containing the surfactant is supplied from the storage tank 9 to the evaporator 5 and is heated to a predetermined temperature while being circulated by the heating circulation system 8. The water vapor evaporated in the evaporator 5 is cooled by the cooler 10 and collected in the storage tank 11 as condensed water.
As the non-volatile components such as salt of the liquid to be processed in the evaporator 5 are concentrated, the surfactant contained in the liquid to be processed is also concentrated. Here, when the concentration of the surfactant in the liquid to be treated rises, in the conventional evaporator, the liquid to be treated in the evaporator 5 is vigorously foamed, and the foam overflows to the condensation system side. On the other hand, in the waste liquid treatment apparatus of the present invention, the liquid to be treated in the evaporator 5 is extracted and concentrated by evaporating while circulating in the activated carbon tower 1. Since the surfactant in the liquid to be treated is adsorbed and removed by the activated carbon tower 1, the concentration of the surfactant in the liquid to be treated is maintained at a low concentration. Thereby, in the waste liquid treatment apparatus of the present invention, it is possible to suppress foaming of the liquid to be treated in the evaporation can 5. Also, activated carbon tower 1
A monitor of the UV meter 3 is installed at the outlet of the circulation system of 1 to measure the concentration of the surfactant in the liquid to be treated. When the adsorption performance of the activated carbon tower 1 deteriorates due to a long-time evaporation operation, the activated carbon is replaced with new activated carbon. When the concentration of the surfactant in the liquid to be treated in the storage tank 1 is high from the initial stage, a pretreatment device is installed to remove the surfactant before supplying it to the evaporator 5.

Next, FIG. 2 shows a system diagram of another embodiment of the present invention. This apparatus comprises a storage tank 9 for the liquid to be treated, a film evaporation concentrator 14 using a hydrophobic porous membrane for evaporating the liquid to be processed, a system 8 for supplying the liquid to be processed to the film evaporation concentrator 14 and heating and circulating it.
The system 12 for extracting the liquid to be treated from the concentrated liquid tank 15, circulating the cooling water to the system 4 and the membrane evaporation concentrator 14 circulating to the activated carbon tower 1, and condensing and recovering the generated vapor, and the concentrated liquid to be treated. It comprises a storage tank 13 for storing. In addition, the concentrated circulation tank 15, the circulation pump 6 and the heater 7 are provided in the heating circulation system of the liquid to be treated.
Is provided. A circulation system 4 to the activated carbon tower 1 is provided with an activated carbon tower 1, a circulation pump 2 and a UV meter 3. The condensed water recovery system is provided with a cooling water tank 16, a circulation pump 17, and a cooler 10.

The operation of the waste liquid treatment apparatus of the invention shown in FIG. 2 will be described. The waste liquid containing the surfactant is supplied from the storage tank 9 to the concentrated liquid tank 15 and is heated to a predetermined temperature while being circulated by the heating circulation system 8. Membrane evaporation concentrator 14
The water vapor evaporated in 1 is condensed to the cooling water side through the film, and is collected in the condensed water tank 11 via the cooling water tank 16. As the salt content of the liquid to be treated in the concentrated liquid tank 15 is concentrated,
Here, when the concentration of the surfactant in the liquid to be treated increases, the hydrophobic porous membrane used in the conventional membrane evaporation concentrator is made hydrophilic, and the concentrated liquid leaks. On the other hand, in the waste liquid treatment apparatus of the present invention, the liquid to be treated is extracted from the concentrated liquid tank 15 and is concentrated while being circulated to the activated carbon tower 1. Since the surfactant in the liquid to be treated is adsorbed and removed by the activated carbon tower 1, the concentration of the surfactant in the liquid to be treated is maintained at a low concentration. From this, in the waste liquid treatment apparatus of the present invention, leakage of the concentrated liquid due to the hydrophilicity of the hydrophobic porous membrane used in the membrane evaporative condenser 14 can be suppressed. A UV meter 3 is installed at the outlet of the circulation system of the activated carbon tower 1 to measure the concentration of the surfactant in the liquid to be treated. When the adsorption performance of the activated carbon tower 1 deteriorates due to a long-time evaporation operation, the activated carbon is replaced with new activated carbon. When the concentration of the surfactant in the liquid to be treated in the storage tank 1 is high from the initial stage, a pretreatment device is installed to remove the surfactant before supplying it to the membrane evaporation concentrator 14.

[0012]

EFFECTS OF THE INVENTION According to the present invention, a stable concentration process can be performed on a waste liquid containing a surfactant without deteriorating the evaporation process function of the evaporator.

[Brief description of drawings]

FIG. 1 is a system diagram of an embodiment of the present invention.

FIG. 2 is a system diagram of another embodiment of the present invention.

FIG. 3 is a system diagram of a conventional waste liquid treatment device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Activated carbon tower, 4 ... System which circulates to activated carbon tower 1, 5 ... Evaporation can, 8 ... Heating circulation system of to-be-processed liquid, 12 ... Condensed water recovery system, 14 ... Membrane evaporation concentrator, 19 ... Pretreatment device .

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Takashi Hayada Inventor Takashi 7-2, Omika-cho, Hitachi City, Ibaraki Hitachi Ltd. Energy Research Laboratory (72) Inventor Toshio Sawa 7-2, Omika-cho, Hitachi City, Ibaraki Prefecture No. 1 Incorporated Hitachi, Ltd. Energy Research Laboratory (72) Inventor Tatsuo Izumida 3-1-1, Saiwaicho, Hitachi-shi, Ibaraki Hitachi Ltd. Hitachi factory

Claims (2)

[Claims] 1. A waste liquid treatment apparatus for recovering pure water by evaporating a waste liquid containing a surfactant and salt generated in a nuclear power plant facility with an evaporator and concentrating the salt content of a liquid to be treated to recover pure water. A waste liquid treatment apparatus comprising a system for circulating a liquid to be treated, which has been vaporized in an evaporator, to an activated carbon tower. 2. A waste liquid treatment method for recovering pure water by subjecting a waste liquid containing a surfactant and salt generated in a nuclear power plant facility to evaporation treatment, concentrating the salt content of the liquid to be treated, and collecting pure water. A method for treating waste liquid, which comprises subjecting the liquid to evaporation treatment while circulating the liquid through an activated carbon tower.