KR20210048932A - Hybrid waste-water disposal system - Google Patents

Abstract

The present invention proposes a wastewater disposal system. The wastewater disposal system according to one embodiment of the present invention includes: a wastewater pretreatment unit for pretreating wastewater; a wastewater stripping unit for separating dissolved gases and low-boiling-point substances by heating or depressurizing the pretreated wastewater; an incinerator for incinerating the dissolved gas and low-boiling point substances separated in the wastewater stripping unit; a primary concentration unit including a hybrid thermal vapor recompression (TVR) concentrator and a live steam concentrator for evaporating and concentrating the stripped wastewater in the wastewater stripping unit; a secondary concentration unit for concentrating the concentrate concentrated in the first concentration unit; a condensing unit receiving cooling water from a cooling tower and condensing the evaporated vapor generated in the primary and secondary concentration units; a condensate stripping unit for stripping the condensed water transferred from the condensing unit; a microorganism processing unit for supplying and processing microorganisms to the condensed water transferred from the condensed water stripping unit; and a treated water recycling unit that recycles the treated water treated through the microorganism processing unit, wherein the treated water recycling unit supplies the treated water to the cooling tower, and uses as make-up water for the cooling water evaporated in the condensing unit.

Description

Wastewater treatment system{HYBRID WASTE-WATER DISPOSAL SYSTEM}

The present invention relates to a wastewater treatment system, and relates to a zero liquid discharge (ZLD) system for reusing treated water by treating wastewater, and discharging a small amount of sludge excluding treated water to the outside.

Recently, the interest of companies and academia is increasing in the Zero Liquid Discharge (ZLD) system. In addition, there are reasons such as a gradual increase in the supply price of industrial water, an increase in production costs due to an increase in discharge charges due to the regulation on the total amount of discharged water, and a legislated legal requirement for recycling more than 1/3 of the amount of wastewater discharged. It can be said that the value judgment of companies and academia itself to get rid of it is greater.

Recently, there has been a movement to introduce a total amount of non-discharge system treatment rather than a specific waste water treatment.

In the case of overseas, the zero-discharge system has been introduced for a long time, but it is estimated that about 100 sites are currently in operation in Japan, and thousands are installed and operated in the United States.

The discharge-free system in Japan is mainly installed in high-value-added semiconductor factories, but requires a large amount of high-quality water, or the installation area corresponds to a specific pollutant emission restricted area such as a national park, which requires expensive installation and operation costs. Has been introduced and operated.

This wastewater-free system (ZLD) is a process of reusing treated water by treating wastewater and discharging a small amount of sludge to the outside, largely through reverse osmosis (RO) ZLD, a separation process using a reverse osmosis membrane, and heating. It is classified into Thermal ZLD, which is a separation process of evaporation and concentration and phase change. Among them, thermal ZLD is an evaporative concentration technology used in the food industry in the 19th century, but it is a process that is applied to various industrial fields as the demand for re-use of water resources and reinforced environmental regulations as described above increase.

The thermal ZLD process using phase change by heating is particularly effective for hardly decomposable wastewater, and depending on the method of heating the wastewater, the waste heat steam heating method using a boiler, the method of evaporating under vacuum decompression, the flame direct heating method, etc. have.

In order to perform such a thermal ZLD process, a vertical tube falling film evaporator has been mainly used in the prior art, and has been proposed through Korean Patent No. 10-1152305.

The present application is to solve the problems of the prior art described above, and aims to provide a wastewater treatment system that builds a ZLD (Zero Liquid Discharge) system in which treated water generated in the process of concentrating wastewater is not discharged. It is done.

However, the technical problem to be achieved by the present embodiment is not limited to the technical problems as described above, and other technical problems may exist.

As a technical means for achieving the above technical problem, the wastewater treatment system according to the first embodiment of the present application includes: a wastewater pretreatment unit for pretreating wastewater; A wastewater stripping unit that separates dissolved gases and low-boiling substances by heating or decompressing the pretreated wastewater; An incinerator for incineration of dissolved gas and low boiling point substances separated by the wastewater stripping unit; A primary concentrator including a hybrid thermal vapor recompession (TVR) concentrator and a live seam concentrator for evaporating and concentrating the wastewater stripped from the wastewater stripping unit; A second concentrating unit for concentrating the concentrate concentrated in the first concentrating unit; A condensing unit receiving cooling water from the cooling tower and condensing evaporated vapor generated in the first and second concentrating units; A condensed water stripping unit for stripping the condensed water transferred from the condensing unit; A microbial treatment unit that supplies and treats microbes to the condensed water transferred from the condensate stripping unit; And a treated water recycling unit for recycling the treated water treated by the microbial treatment unit, wherein the treated water recycling unit supplies treated water to the cooling tower and uses it as supplemental water for cooling water evaporated from the condensing unit.

A wastewater treatment method according to a second embodiment of the present application includes the steps of pretreating wastewater through a wastewater pretreatment unit; Stripping the pretreated wastewater through a wastewater stripping unit; Incineration of dissolved gas and low boiling point substances generated in the step of stripping the wastewater in an incinerator; Concentrating by supplying the wastewater subjected to the stripping step to a first concentrator for evaporating and concentrating first; Concentrating by supplying the concentrated solution concentrated in the first concentrating unit to a second concentrating unit for secondary evaporation and concentrating; Condensing the evaporated vapor generated in the first and second concentrating units through a condensing unit; Stripping the condensed water condensed in the condenser through a condensed water stripping unit; Treating the stripped condensed water through a microbial treatment unit; And recycling the treated water treated through the microbial treatment step.

According to the above-described problem solving means of the present application, the effect of remarkably reducing environmental pollution by constructing a ZLD (Zero Liquid Discharge) system in which treated water generated in the process of concentrating wastewater is not discharged will be greatly improved. I can.

1 is a schematic diagram of a wastewater treatment system according to an embodiment of the present invention.
2 is a view for explaining a wastewater stripping unit according to an embodiment of the present invention.
3 is a view for explaining a condensate stripping unit according to an embodiment of the present invention.
4 is a flowchart illustrating a wastewater treatment method according to an embodiment of the present invention.

Hereinafter, embodiments of the present application will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art may easily implement the present application. However, the present application may be implemented in various different forms and is not limited to the embodiments described herein. In addition, in the drawings, parts irrelevant to the description are omitted in order to clearly describe the present application, and similar reference numerals are attached to similar parts throughout the specification.

Throughout this specification, when a part is said to be "connected" with another part, this includes not only the case that it is "directly connected", but also the case that it is "electrically connected" with another element interposed therebetween. do.

Throughout this specification, when a member is positioned “on” another member, this includes not only the case where a member is in contact with the other member, but also the case where another member exists between the two members.

In the entire specification of the present application, when a certain part "includes" a certain component, it means that other components may be further included, rather than excluding other components unless specifically stated to the contrary. The terms "about", "substantially", etc. to the extent used throughout the present specification are used at or close to the numerical value when manufacturing and material tolerances specific to the stated meaning are presented, and the understanding of the present application To assist, accurate or absolute numerical values are used to prevent unreasonable use of the stated disclosure by unscrupulous infringers. As used throughout the specification of the present application, the term "step to (to)" or "step of" does not mean "step for".

The present application relates to a wastewater treatment system 10.

1 is a schematic diagram of a wastewater treatment system according to an embodiment of the present invention, FIG. 2 is a view for explaining a wastewater stripping unit according to an embodiment of the present invention, and FIG. 3 is a condensed water according to an embodiment of the present invention. A diagram for explaining a stripping unit, and FIG. 4 is a flow chart for explaining a wastewater treatment method according to an embodiment of the present invention.

First, the wastewater treatment system 10 (hereinafter referred to as'wastewater treatment system 10') according to an embodiment of the present application will be briefly described.

The wastewater treatment system 10 evaporates the wastewater through a concentrator to generate a concentrated liquid having a high concentration and high salinity (more than 50% moisture content), and the evaporation vapor generated at this time is liquefied into condensed water through a condenser. It relates to a wastewater-free treatment system 10 that reuses treated water generated by removing and purifying odors through biological treatment. In addition, the types of wastewater to be treated in the present invention include organic waste (sewage/wastewater sludge, animal/vegetable residue, food company waste, fish farm and pig farming waste, food waste, heavy metal waste, etc.) and refractory wastewater (food waste, Organic concentrated wastewater, organic compound wastewater, heavy metal wastewater, salt wastewater, etc.), but is not limited thereto.

Hereinafter, a wastewater treatment system 10 according to an embodiment of the present disclosure will be described in detail with reference to FIGS. 1 to 6.

The wastewater treatment system 10, referring to FIG. 1, is a wastewater pretreatment unit 100, a wastewater stripping unit 200, a primary concentration unit 400, a secondary concentration unit 500, and an evaporative vapor condensation unit 600. ), a condensed water stripper 710, a microorganism treatment unit 800, and a treated water recycling unit 900.

The wastewater pretreatment unit 100 is a device that performs a process of removing and separating relatively large impurities contained in wastewater through precipitation or related reactions, and various types of pretreatment devices may be employed depending on the physical properties of the wastewater. have. Exemplarily, the wastewater pretreatment unit 100 is a caustic soda treatment tank for neutralizing acidic wastewater such as desulfurization wastewater by inputting caustic soda, an alum treatment tank for separating organic substances by introducing a coagulant such as alum, and a polymer coagulant. It may include at least one or more of a polymer treatment tank for sedimenting the suspended solids through, etc., and a sedimentation separation tank for separating the precipitates by finally storing and chemically treating wastewater for a predetermined period, but is not limited thereto.

The wastewater stripping unit 200 strips the pretreated wastewater. The above-described stripping refers to heating or depressurizing a liquid to release a dissolved gas and a low-boiling point substance of the liquid into the gas phase. Since dissolved gases and low-boiling substances are factors that severely deteriorate the operation performance of the concentrator, it is preferable to separate the wastewater before introducing it into the concentrator.

In addition, referring to FIG. 2, the wastewater stripping unit 200 preheats wastewater using evaporative steam generated from the hybrid thermal steam recompression concentrator 410 and the live steam concentrator 420 of the primary concentrator 400. A wastewater preheater 210, a wastewater stripper 220 that separates dissolved gas and low-boiling substances by heating or decompressing wastewater, and a first condensation trap 230 for condensing the evaporative vapor discharged from the wastewater preheater 210. I can.

Specifically, the pre-treated wastewater may be preheated by evaporative steam in the wastewater preheater 210 in the hybrid thermal steam recompression concentrator 410 and the live steam concentrator 420, and then may be supplied to the wastewater stripper 220. In addition, the wastewater supplied to the wastewater stripper 220 may be supplied to the upper portion and moved to the lower portion to separate dissolved gas and low-boiling point substances in the wastewater, and then supplied to the primary concentrator 400. In addition, the evaporative vapor discharged from the wastewater preheater 210 may be condensed through the first condensation trap 230 and supplied to a condensate stripper 710 to be described later.

The incinerator 300 incinerates the dissolved gas and low boiling point substances separated by the wastewater stripping unit 200. In addition, the incinerator 300 may incinerate the evaporated vapor generated in the first concentrating unit 400 and the second concentrating unit 500 when the amount of evaporated vapor that can be processed in the condensing unit 600 is exceeded. . In addition, the incinerator 300 may preferentially treat dissolved gas and low-boiling point substances discharged from the wastewater stripping unit 200 and substances generated from the vacuum pump exhaust of the concentrating unit, thereby greatly improving the water quality of the condensed water.

In preparation for a case in which a large amount of dissolved gas generated from the wastewater stripper 220 is generated, the evaporation amount of the LBT (Low Boiling Temperatur) solution is selected to be about 125%, thereby preventing a decrease in the treatment capacity of the concentrator.

In addition, the wastewater stripped from the wastewater stripping unit 200 is evaporated and concentrated by sequentially passing through the first concentrating unit 400 and the second concentrating unit 500.

The primary concentrator 400 includes a hybrid thermal vapor recompression (TVR) concentrator 410 and a live steam concentrator 420. In other words, the wastewater stripped from the wastewater stripping unit 200 is supplied to the hybrid thermal steam recompression concentrator 410 or the live steam concentrator 420, and the supplied wastewater is the hybrid thermal steam recompression concentrator 410 or the live steam. It may be concentrated by the concentrator 420 and supplied to the secondary concentrator 500.

The hybrid thermal vapor recompression concentrator 410 recompresses a part of the evaporated vapor generated from the evaporator and reuses it as a heat source of the evaporator, and a detailed description thereof will be omitted since it is a general technique in the concentrator field.

The live steam concentrator 420 may evaporate and concentrate the wastewater pretreated in the wastewater stripping unit 200. In addition, the hybrid thermal vapor recompression concentrator 410 and the live vapor concentrator 420 may use a vertical thin film plate evaporator. In addition, the wastewater treatment system 10, as the vertical thin film elevating concentrator is used, not only has a low installation height of the concentrator, but also reduces the operating weight of the overall device, thereby saving land by installing a concentrator on the upper part of the water treatment facility. Not only that, it is easy to manage the entire facility.

The second concentrating unit 500 may perform a semi-batch operation in which wastewater concentrated in the first concentrating unit 400 is concentrated, and the wastewater is periodically supplied while maintaining a constant internal liquid level during operation. Accordingly, it is possible to continuously treat a larger amount of wastewater. In addition, the second concentrating unit 500 may use the evaporated vapor generated in the first concentrating unit 400 as a heat source for heating wastewater.

In addition, the concentrate concentrated in the secondary concentration unit 500 may be incinerated in the incinerator 300, but the present invention is not limited thereto, and the concentrate may be mixed with fly ash and treated in a solid form.

The condensing unit 600 receives cooling water from the cooling tower and condenses the evaporated vapor generated in the first concentrating unit 400 and the second concentrating unit 500. In addition, the evaporated steam generated in the condensing unit 600 is discharged from the cooling tower as evaporated steam, and the condensed water generated in the condensing unit 600 may be moved to the condensed water stripping unit 700.

The condensed water stripping unit 700 strips the condensed water generated in the evaporative vapor condensing unit 600.

3, the condensed water stripping unit 700 is a condensed water stripper 710 for stripping the condensed water generated in the condensing unit 600 and the condensed water of the condensed water stripper 710 to evaporate vapor of the first condensing unit 400. It may include a condensed water heater 720 that is heated by using. In other words, the condensed water supplied to the condensed water stripper 710 may be supplied to the upper portion and moved to the lower portion, so that the dissolved gas and the low-boiling point substance in the condensed water are separated, and then stored in the lower portion. In addition, the condensed water stored in the lower part may be supplied to the condensed water heater 720 to be heated, and then supplied to the condensed water stripper 710 for stripping. At this time, the generated dissolved gas and low boiling point material may be supplied to the incinerator 300 to be incinerated.

The microorganism treatment unit 800 supplies and processes microorganisms to the condensed water transferred from the condensate stripper 710. In other words, the microbial processing unit 800 may decompose and remove organic substances that can be decomposed by living organisms among organic substances present in the condensed water through microorganisms such as algae, bacteria, and protozoa.

The treated water recycling unit 900 recycles the treated water treated through the microbial treatment unit 800. Specifically, the treated water recycling unit 900 may supply the treated water to the cooling tower and use it as supplemental water for the cooling water evaporated from the condensing unit 600. In addition, the treated water recycling unit 900 supplies the treated water to a semi-dry reactor (SDR) of the incinerator 300, or uses it as scrubber washing water of the incinerator 300, or as process water for neutralizing waste acid. Can be used.

Accordingly, the wastewater treatment system 10 can completely treat the treated water in the system 10, thereby constructing a zero liquid discharge (ZLD) system.

Hereinafter, a wastewater treatment method according to an embodiment of the present invention will be described with reference to FIG. 4.

In step S110, the wastewater stock solution may be pretreated. Specifically, in step S110, the wastewater is supplied and relatively large impurities contained in the wastewater may be removed and separated through precipitation or a related reaction.

In step S120, the pretreated wastewater is stripped. In other words, in step S120, the pretreated wastewater may be heated or depressurized to discharge a liquid dissolved gas and a low boiling point substance into the gas phase. For example, after preheating the pre-treated wastewater through the wastewater preheater 210, the preheated wastewater may be supplied to the wastewater stripper 220 to strip the wastewater.

In step S130, the dissolved gas and the low boiling point material separated in step S120 are incinerated using the incinerator 300.

In step S140, the wastewater that has undergone the springing step is supplied to the first concentrator 400 for evaporating and concentrating first and condensing it. Specifically, in step S140, wastewater may be supplied to the hybrid thermal vapor recompression concentrator 410 and the live vapor concentrator 420, respectively, and evaporated and concentrated. The evaporated vapor generated at this time may be supplied to a condenser and condensed. In addition, the evaporative vapor generated in the first condensing unit 400 may be supplied to the wastewater preheater 210 or the condensate heater 720 to be used as a heat source for heating wastewater or condensed water. In addition, when the amount of evaporated vapor that can be processed in the condensing unit 600 is exceeded, the evaporated vapor generated in the first condensing unit is supplied to the incinerator 300 and can be immediately incinerated.

In addition, in the case of the hybrid thermal vapor recompression concentrator 410, the evaporated vapor is supplied to a thermal vapor recompession (TVR) and recompressed, so that it can be reused as a heat source of the evaporator.

In step S150, the concentrated solution concentrated in the first concentrating unit 400 is concentrated through the second concentrating unit 500. For example, the secondary concentrating unit 500 may be operated in a semi-batch type that periodically supplies wastewater while maintaining a constant internal liquid level during operation.

In step (S160), the cooling water is supplied from the cooling tower and condensed through the condensing unit 600 evaporated vapor generated in the first concentrating unit 400 and the second concentrating unit 500.

In step S170, the condensed water condensed in the condensing unit 600 is stripped through the condensed water stripping unit 700. In other words, the condensed water may be heated or depressurized by using the condensed water stripping unit 700 to discharge dissolved gas and non-low point substances remaining in the condensed water into the gas phase.

In step S180, the condensed water is treated through the microbial treatment unit 800. In other words, the condensed water can be decomposed through microorganisms such as algae, bacteria, and protozoa in the microbial treatment unit.

In step S190, the treated water may be recycled. In detail, in step S180, the treated water may be supplied to the cooling tower and used as supplemental water for the cooling water evaporated in the condensing unit 600.

In addition, step (S190) is a step of supplying the treated water to the incinerator 300 semi-dry reactor (SDR: Semi-Dry Reaction); Using the treated water as scrubber washing water of the incinerator 300; And using the treated water as process water for neutralizing waste acid.

The foregoing description of the present application is for illustrative purposes only, and those of ordinary skill in the art to which the present application pertains will be able to understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present application. Therefore, it should be understood that the embodiments described above are illustrative and non-limiting in all respects. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as being distributed may also be implemented in a combined form.

The scope of the present application is indicated by the claims to be described later rather than the detailed description, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present application.

10: wastewater treatment system
100: wastewater pretreatment unit
200: wastewater stripping section
210: wastewater preheater 220: wastewater stripper
230: first condensation trap
300: incinerator
400: primary concentration unit
410: hybrid thermal vapor recompression evaporator
420: live steam concentrator
500: secondary concentration unit
600: condensing part
700: condensate stripping part
800: microbial processing unit
900: treated water recycling department

Claims (12)

In the wastewater treatment system,
A wastewater pretreatment unit for pretreating wastewater;
A wastewater stripping unit that separates dissolved gases and low-boiling substances by heating or decompressing the pretreated wastewater;
An incinerator for incineration of dissolved gas and low boiling point substances separated by the wastewater stripping unit;
A primary concentrator including a hybrid thermal vapor recompession (TVR) concentrator and a live steam concentrator for evaporating and concentrating the wastewater stripped from the wastewater stripping unit;
A second concentrating unit for concentrating the concentrate concentrated in the first concentrating unit;
A condensing unit receiving cooling water from the cooling tower and condensing evaporated vapor generated in the first and second concentrating units;
A condensed water stripping unit for stripping the condensed water transferred from the condensing unit;
A microbial treatment unit that supplies and treats microbes to the condensed water transferred from the condensate stripping unit; And
Including a treated water recycling unit for recycling the treated water treated through the microbial treatment unit,
The treated water recycling unit supplies treated water to the cooling tower and uses it as supplemental water for cooling water evaporated from the condensing unit.
The method of claim 1,
The treated water recycling unit is a wastewater treatment system that supplies the treated water to a semi-dry reactor (SDR) of the incinerator.
The method of claim 1,
The treated water recycling unit is a wastewater treatment system that uses the treated water as scrubber washing water of the incinerator.
The method of claim 1,
The treated water recycling unit is a wastewater treatment system that uses the treated water as process water for neutralizing waste acid.
The method of claim 1,
The incinerator
When the amount of evaporated vapor that can be treated in the condensing unit is exceeded, the evaporated vapor generated in the first and second condensing units is incinerated.
The method of claim 1,
The incinerator is a wastewater treatment system that preferentially treats dissolved gas and low boiling point substances discharged from the wastewater stripping unit, and substances generated from the vacuum pump exhaust of the concentration unit.
In the wastewater treatment method,
Pretreating wastewater through a wastewater pretreatment unit;
Stripping the pretreated wastewater through a wastewater stripping unit;
Incineration of dissolved gas and low boiling point substances generated in the step of stripping the wastewater in an incinerator;
Concentrating by supplying the wastewater subjected to the stripping step to a first concentrator for evaporating and concentrating first;
Concentrating by supplying the concentrated solution concentrated in the first concentrating unit to a second concentrating unit for secondary evaporation and concentrating;
Condensing the evaporated vapor generated in the first and second concentrating units through a condensing unit;
Stripping the condensed water condensed in the condensing unit through a condensed water stripping unit;
Treating the stripped condensed water through a microbial treatment unit; And
Wastewater treatment method comprising the step of recycling the treated water treated through the microbial treatment step.
The method of claim 7,
Recycling the treated water is
A wastewater treatment method comprising the step of supplying the treated water to a cooling tower and utilizing it as make-up water.
The method of claim 8,
Recycling the treated water is
The wastewater treatment method further comprising the step of supplying the treated water to a semi-dry reactor (SDR) of the incinerator.
The method of claim 8,
Recycling the treated water is
The wastewater treatment method further comprising the step of using the treated water as scrubber washing water of the incinerator.
The method of claim 8,
The step of recycling the treated water
Wastewater treatment method comprising the step of using the treated water as process water for neutralizing waste acid.
The method of claim 7,
When the amount of evaporated vapor that can be treated in the condensing unit is exceeded, the method of treating wastewater further comprises treating the evaporated vapor generated in the first concentrating unit and the second concentrating unit in the incinerator.

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