KR100550976B1 - Treatment system and method for water discharged from a sewage treatment works - Google Patents

Abstract

The present invention relates to a sewage effluent treatment system and treatment method for treating sewage effluent, in particular, sewage effluent containing a high concentration of salt to produce agricultural water, industrial water, dry water maintenance water, groundwater reclaimed water, and indirect drinking water. The treatment system according to the present invention comprises: a pretreatment unit for filtering primary insoluble foreign matters contained in sewage effluent and removing microorganisms and organic matter to produce primary treated water; A backwash type microfiltration unit that filters the non-soluble debris that has not been filtered in the pretreatment unit to produce secondary treated water; A membrane cleaning unit for backwashing the backwash type microfiltration unit; A reverse osmosis unit for treating the secondary treated water and separating the secondary treated water and the concentrated water; And a concentrated water treatment unit for treating the concentrated water.

Sewage, effluent, reuse, reverse osmosis, backwash, high salinity, concentrated water, ultraviolet ray, screen, activated carbon,

Description

Sewage effluent treatment system and treatment method {TREATMENT SYSTEM AND METHOD FOR WATER DISCHARGED FROM A SEWAGE TREATMENT WORKS}

1 is a schematic configuration diagram of a sewage effluent treatment system according to an embodiment of the present invention.

2 is a block diagram of a sewage effluent treatment method according to an embodiment of the present invention.

The present invention relates to a treatment system and method for treating sewage effluent, and more particularly, to sewage effluent, in particular sewage effluent containing a high concentration of salt, agricultural water, industrial water, dry water maintenance water, groundwater reclaimed water and indirect A sewage effluent treatment system and treatment method for producing drinking water.

As demand for water increases rapidly due to rapid economic development and population growth, various methods for stable water supply have recently been considered.

As one of the above measures, large-scale river development and groundwater development are being reviewed and promoted. Recently, due to the above-mentioned river development, water shortages occur due to the dryness of rivers in some regions every year, and groundwater due to the poor development of groundwater. As pollution and depletion intensify, it is increasingly difficult to secure stable water sources.

In particular, in coastal areas, due to unreasonable groundwater development, seawater penetrates into the underground aquifer and deepens contamination of the groundwater itself, which makes it impossible to use groundwater.

Therefore, in order to prevent the above-mentioned water shortage and groundwater contamination, a method of using sewage effluent is under consideration. Sewage effluent is most suitable to be used as an alternative water source because a certain amount continuously occurs even during drought or natural disaster. However, in order to reuse sewage effluent, there is a need for a technology capable of completely removing various pollutants contained in the effluent.

However, conventionally, by treating only the effluent discharged from the sewage treatment plant using only a simple filtration facility, for example, a sand filtration or an activated carbon filtration facility, the treated water filtered by the filtration facility is a low-level job such as toilet water, sprinkling water, and landscape water. It could only be used as water.

In particular, a high salinity sewage effluent containing high concentrations of salts is generated in a sewage treatment plant located in the coastal region, where the high salinity sewage effluent is introduced into a sewage treatment plant through a poor sewage pipe when the tidal water is high tide, It occurs when high salt sewage from sashimi is introduced into sewage treatment plant.

The high salinity sewage deteriorates the treatment efficiency of existing biological treatment sewage treatment plants, and because the high concentration of salt is contained in the effluent, reuse of the high salinity sewage is extremely limited.

In order to reuse the high salt sewage effluent, a process using a reverse osmosis system is generally applied. However, since the reverse osmosis system is not a treatment device but a simple physical separation device, the existing sewage effluent coming into the reverse osmosis system is separated into reusable treated water and concentrated water that is more polluted than the existing effluent. There is a problem of generating pollution, the conventional reverse osmosis system has a problem that can not operate efficiently due to the pollutants contained in the sewage effluent.

Therefore, in recent years when a large amount of agricultural water and industrial water are required due to water shortages, there is a need for a method of more strictly and stably managing the water quality of treated water.

The present invention has been made to solve the above problems of the prior art, and an object of the present invention is to provide a water treatment system and method capable of efficiently treating sewage effluent, particularly sewage effluent containing a high concentration of salt.

The present invention to achieve the above object,

A pretreatment unit which filters non-soluble foreign matter contained in sewage effluent and removes microorganisms and organics to produce primary treated water;

A backwash type microfiltration unit that filters the non-soluble debris that has not been filtered in the pretreatment unit to produce secondary treated water;

A membrane cleaning unit for backwashing the backwash type microfiltration unit;

A reverse osmosis unit separating the secondary treated water into tertiary treated water and concentrated water; And

A concentrated water treatment unit for treating the concentrated water;

It provides a sewage effluent treatment system comprising a.

The pretreatment unit includes a microfiltration screen or drum screen for removing insoluble foreign matters, such as coarse suspended matter, a storage tank for storing sewage effluent passing through the screen, and a storage tank by removing microorganisms and organic substances contained in the discharge water stored in the storage tank. It includes a pollution prevention device to prevent contamination, the pollution prevention device may be made of an ultraviolet installation installed in the storage tank to perform ultraviolet sterilization. The pretreatment unit receives the sewage effluent and processes it to produce primary treated water.

In addition, the backwash type microfiltration unit for treating the primary treated water to produce the secondary treated water may include a pressure vessel and separation membranes immersed in the vessel, and the separation membranes have a pore size of 0.005 to 0.5. Μm, and may be formed of a membrane having a hydrophilic treatment selected from a group of hollow fiber membranes including polysulfone, polyacrylonitrile, polyethylene, and polypropylene. In addition, the backwash type microfiltration unit includes a structure capable of backwashing water and backwashing air into and out of the separation membrane, and a high strength hollow fiber membrane reinforced with fibers in the hollow fiber membrane may be used so that the hollow fiber membrane is not singled out due to frequent backwashing. .

On the other hand, the reverse osmosis unit is a treatment tank for storing the second treatment water passed through the backwash type precision filter, a pump for pumping the treatment water stored in the treatment tank and the protective filter for filtering the treated water, 2 passed through the protective filter Reverse osmosis equipment for separating primary treated water into tertiary treated and concentrated water. Here, the protective filter can be selectively removed.

The concentrated water treatment unit includes an activated carbon adsorption facility for adsorbing organic matter contained in the concentrated water, and an activated carbon regeneration facility for continuously regenerating activated carbon having reduced adsorption performance.

In addition, the treatment system further includes a backwash type microfiltration unit, a membrane washing unit to assist backwashing of the activated carbon adsorption plant, and an agglomeration sedimentation unit to coagulate and precipitate the backwash drainage.

The membrane washing unit includes a backwash tank for storing backwash water, a feed pump for supplying the backwash water to the microfiltration unit, and a filter for filtering backwash water. In this case, the reverse wash water may be a reverse osmosis concentrated water discharged from the reverse osmosis facility and / or reverse osmosis concentrated discharged water discharged from the activated carbon adsorption facility. Here, the filter can be selectively removed.

In addition, the present invention to achieve the above object,

A pretreatment step of filtering the insoluble foreign matter contained in the sewage effluent and removing the microorganisms and organic matter to produce the first treated water;

A backwash type microfiltration step of filtering the insoluble foreign matter not filtered in the pretreatment step to produce a secondary treated water;

A reverse osmosis step of separating organic materials, microorganisms, and soluble substances contained in the secondary treated water to produce tertiary treated water and concentrated water;

A concentrated water treatment step of treating the concentrated water to produce concentrated effluent; And

A membrane wash step of backwashing the backwash microfiltration unit;

It provides a sewage effluent treatment method comprising a.

Here, the membrane washing step includes a first washing step using the concentrated water or concentrated effluent water as backwash water, and a second washing step using air, and after performing the second washing step, It is preferable to inflow and discharge the backwash water out of the system.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Figure 1 shows a schematic diagram of a high salinity sewage effluent treatment system according to an embodiment of the present invention, Figure 2 shows a block diagram of a high salt sewage effluent treatment method according to an embodiment of the present invention.

The sewage effluent treatment system according to the embodiment of the present invention has a fine filtration screen as a pretreatment unit 10 that collects and primarily filters sewage effluent (W), particularly high salt sewage effluent, discharged through biological treatment in a sewage treatment plant ( 12) or contamination of the drum screen and the storage tank 14 to store the sewage effluent passing through the screen 12 and the microorganisms and organic substances contained in the discharge water stored in the storage tank 14 to prevent the storage tank contamination. Include preventers.

The fine filtration screen 12 or the drum screen prevents the pump impeller from being damaged due to coarse suspended matter, plants, seeds, etc., which are not processed in the existing sewage treatment plant, and are suspended and accumulated in the reservoir 14. Prevent the phenomenon. Although not shown in detail, the fine filtration screen 12 is automatically backwashed, and is made of stainless material to prevent corrosion due to high salinity sewage.

The primary treatment water W1 that has passed through the fine filtration screen 12 stays in the storage tank 14 and then flows into the backwash type microfiltration unit 20 for secondary treatment. The phenomenon in which the storage tank 14 is contaminated by organic matter and microorganisms contained in the primary treated water W1 during the stay in the storage tank 14, and the backwash type microfiltration unit 20 and the reverse osmosis unit 30 at the rear stage In order to prevent the microbial contamination of the), the inside of the storage tank 14 is mounted by immersing the ultraviolet installation (16). Here, the ultraviolet light facility 16 acts as a pollution prevention device.

The primary treated water W1 sterilized by the ultraviolet light facility 16 is transferred to the backwash type microfiltration unit 20 by the pump P1. The backwash fine filtration unit 20 includes a pressure vessel 22 and a backwash fine filtration module 24, the filtration module 24 being mounted in plural in the pressure vessel 22.

The pressure vessel 22 is made of stainless steel to prevent corrosion, and is designed to withstand a certain pressure, for example, 5 kgf / ㎠ or less, and the primary treatment water inlet and secondary treatment water outlet, backwash Equipped with drain outlet, air inlet and module mounting plate.

The backwash microfiltration module 24 mounted inside the pressure vessel 22 has a pore size of 0.005 to 0.5 μm, polysulfone, polyacrylonitrile, polyethylene, and polypropylene ( It is preferable that it is selected from the group of hollow fiber membranes, such as polypropylene, and is a film of a material subjected to hydrophilic treatment.

In addition, it is preferable to use a high-strength hollow fiber membrane reinforced by inserting the filament into the hollow fiber as the backwash type microfiltration module 24, which is to prevent the hollow yarns from being single yarns due to frequent backwashing of the hollow fiber membrane.

Production of the secondary treated water (W2) in the backwash type microfiltration unit (20) is by pressurization of the pump (P1), wherein the fine suspended solids and reservoir (14) that were not removed from the microfiltration screen (12) Microorganisms sterilized in are attached to the surface of the hollow fiber membrane of the backwash microfiltration module 24.

The suspended solids attached in this way are backwashed by the backwashing process of the present embodiment described later, and the suspended solids desorbed by the backwashing process are discharged out of the system.

The efficient operation of the backwash type microfiltration unit 20 will influence the operation efficiency of the entire water treatment system. Therefore, for efficient operation of the backwash microfiltration unit 20, it is desirable to install a timer, a programmable logic control (PLC), and an inverter in the system.

Most of the suspended solids adhering to the surface of the hollow fiber membrane of the backwash type microfiltration unit 20 are removed by the backwashing process, but if there are some of the suspended solids, the backwash type microfiltration module 24 is removed. The load is applied and the pressure is increased, which affects the next process. Therefore, the filtration module 24 is preferably operated at a low pressure of 1 kgf / cm 2 or less.

On the other hand, the suspended matter desorbed from the hollow fiber membrane is introduced into the primary treatment water (W1) in the storage tank (14) and discharged out of the system of the backwash type microfiltration unit (20).

The secondary treated water W2 having passed through the backwash type microfiltration unit 20 is supplied to the treated water tank 34 before being supplied to the reverse osmosis facility 32. In general, the reverse osmosis installation 32 is operated under high pressure conditions. Therefore, it is preferable that the treatment tank 34 can secure a storage capacity of at least 30 minutes so that the continuous operation can be performed without stopping the system operation due to insufficient flow rate during the operation of the reverse osmosis facility 32.

Then, the high pressure pumps P2 and P3 supplying the high pressure to the reverse osmosis facility 32 and the protection filter 36 for protecting the reverse osmosis facility 32 are installed at the front end of the reverse osmosis facility 32, The operation of the pumps P2 and P3 is regulated by a water gauge installed in the treatment tank 32, a programmable logic control (PLC), and a pressure switch.

The secondary treated water W2 that has passed through the high pressure pump P2 and the protective filter 36 is transferred to the reverse osmosis facility 32 by the high pressure pump P3 pressurized above the designed pressure, and the reverse osmosis facility 32 ) Is installed to recover the flow rate more than the design recovery rate (reverse osmosis treated water / reverse osmosis influent).

The reverse osmosis facility 32 separates the secondary treated water (W2) into reusable tertiary treated water (W3) and reverse osmosis concentrated water (W4), and the tertiary treated water (W3) is water quality of heavy and drinking water levels. Has Here, the reverse osmosis concentrated water (W4) refers to water in which organic matter, ultra fine suspended matter, soluble ionic substances, etc. contained in the secondary treated water (W2) are concentrated. The water quality of the reverse osmosis concentrated water (W4) is determined according to the water quality of the secondary treated water (W2) and the recovery rate of the reverse osmosis facility (32), and the concentrated water (W4) is generally based on sewage effluent water quality at an organic concentration. Exceeds. Therefore, it is necessary to treat and discharge the organic matter contained in the reverse osmosis concentrated water (W4) to prevent secondary pollution. Otherwise, the pollutants contained in the high salt sewage effluent are concentrated and discharged to serious nature. Cause contamination.

In order to effectively remove the organic matter, this embodiment includes an activated carbon adsorption plant 42 as the concentrated water treatment unit 40. In addition, the unit 40 further includes an activated carbon regeneration facility 44 for regenerating activated carbon having reduced adsorption performance. The regeneration of activated carbon is performed by burning only the organic matter adsorbed on the activated carbon in the regeneration facility 44.

The reverse osmosis concentrated effluent (W5) that has passed through the activated carbon adsorption plant (42) satisfies the effluent water quality standards and can be discharged out of the system. It is preferable to discharge (W5) to the sea.

Finally, the backwashing process of the backwash type microfiltration unit 50 is demonstrated.

Preferably, the backwashing process is performed sequentially by a program stored in a PLC. In this embodiment, the backwashing water is injected into the hollow fiber membrane using a backwashing water supply pump (P4). And residual air is secondarily removed by aeration of air into the vacuum vessel 22 using a blower.

In addition, the reverse wash water utilizes reverse osmosis concentrated effluent (W5) discharged from the activated carbon adsorption plant (42) or reverse osmosis concentrated water (W4) discharged from the reverse osmosis plant (32). A portion of the water W4 is supplied to the backwash bath 52. And, the backwash water of the backwash tank 52 is supplied to the backwash type microfiltration unit 20 by the backwash water supply pump P4, and the backwash water supplied from the backwash water supply pump P4 to the filter 54. Filtered.

According to this configuration, it is possible to minimize the waste of the treated water as compared to the case of performing the backwashing process using the reverse osmosis treatment water or the backwash type fine filtration unit treatment water.

The backwash drainage W6 discharged from the backwash type microfiltration unit 20 cannot contain a discharge immediately because it contains a large amount of suspended solids. Therefore, the flocculent sedimentation equipment 56 is used to remove suspended solids, and then discharged after treatment to meet the effluent water quality standards. At this time, in order to efficiently remove the suspended solids in the flocculation sedimentation equipment 56, it is preferable to inject alumina sulfate or polyaluminum chloride as a flocculant.

In addition, it is effective to discharge the backwash drainage W6 by diluting the reverse osmosis concentrated water W4 with the reverse osmosis concentrated discharge water W5 adsorbed.

In addition, since the tertiary treated water (W3) treated in the reverse osmosis facility (32) generally has a low pH, it is preferable to use the chemical after neutralizing or degassing ions.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it is within the scope of the present invention.

As described in detail above, according to the embodiment of the present invention, it is possible to remove coarse and fine suspended matter, microorganisms, high molecular weight substances, nitrogen, phosphorus and ionic substances contained in sewage effluent.

Therefore, it is possible to efficiently produce agricultural water, industrial water, dry water maintenance water, groundwater reclaimed water, and indirect drinking water by using sewage effluent, and thus it is possible to effectively cope with the rapidly increasing demand for water.

In addition, the reverse osmosis concentrated water concentrated in the reverse osmosis facility can be treated by the existing sewage effluent water quality standards to remove secondary pollution sources.

Claims (13)

A pretreatment unit which filters non-soluble foreign matter contained in sewage effluent and removes microorganisms and organics to produce primary treated water; A backwash type microfiltration unit that filters the non-soluble debris that has not been filtered in the pretreatment unit to produce secondary treated water; A membrane cleaning unit for backwashing the backwash type microfiltration unit; A reverse osmosis unit for treating the secondary treated water and separating the secondary treated water and the concentrated water; And A concentrated water treatment unit for treating the concentrated water; Sewage effluent treatment system comprising a. The method of claim 1, The pretreatment unit prevents storage tank contamination by removing microorganisms and organic matter contained in the microfiltration screen or drum screen for removing insoluble foreign matter, the storage tank for storing the high salinity sewage effluent passing through the screen, and the discharge water stored in the storage tank. Sewage effluent treatment system comprising a pollution preventer. The method of claim 2, The pollution prevention device is a sewage effluent treatment system which is installed in the storage tank consisting of an ultraviolet facility for performing ultraviolet sterilization. The method of claim 1, And the backwash microfiltration unit comprises a pressure vessel and separators immersed therein. The method of claim 4, wherein The separators have a pore size of 0.005 to 0.5 μm, and have a hydrophilic treatment selected from a hollow fiber membrane group consisting of polysulfone, polyacrylonitrile, polyethylene, and polypropylene. Sewage effluent treatment system. The method of claim 4, wherein The backwash type microfiltration unit includes a structure capable of backwashing water and backwashing air into and out of a separator. The method of claim 1, The reverse osmosis unit is a sewage effluent treatment system comprising a treatment tank for storing the secondary treatment water and a reverse osmosis facility for separating the secondary treatment water supplied from the treatment tank into the tertiary treatment water and concentrated water. The method of claim 7, wherein The concentrated water treatment unit includes an activated carbon adsorption facility for adsorbing organic matter contained in the concentrated water, and an activated carbon regeneration facility for continuously regenerating activated carbon having reduced adsorption performance. The method of claim 8, The membrane washing unit includes a backwash tank for storing backwash water, a feed pump for supplying the backwash water to the precision filtration unit, and an agglomeration sedimentation facility for coagulating sedimentation of backwash drainage. The method of claim 9, A sewage effluent treatment system using concentrated water discharged from the reverse osmosis facility or concentrated discharged water discharged from the activated carbon adsorption facility as reverse washing water. In the water treatment method for treating sewage effluent, A pretreatment step of filtering the insoluble foreign matter contained in the sewage effluent and removing the microorganisms and organic matter to produce the first treated water; A backwash type microfiltration step of filtering the insoluble foreign matter not filtered in the pretreatment step to produce a secondary treated water; A reverse osmosis step of separating organic materials, microorganisms, and soluble substances contained in the secondary treated water to produce tertiary treated water and concentrated water; A concentrated water treatment step of treating the concentrated water to produce concentrated effluent; And A membrane wash step of backwashing the backwash microfiltration unit; Sewage effluent treatment method comprising a. The method of claim 11, The membrane washing step includes a first washing step using the concentrated water or concentrated effluent as backwash water, and a second washing step using air. The method of claim 12, After performing the second washing step, the sewage effluent treatment method for introducing the first treatment water to discharge the backwash water out of the system.

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