KR20100129517A - Gravity flow mbr for treatment of wastewater using metal membrane with macro pore size - Google Patents

Abstract

PURPOSE: A natural elimination type wastewater treatment system with an osculum caliber metal layer in an aeration tank is provided to maintain the high concentration of MLSS. CONSTITUTION: A natural elimination type wastewater treatment system comprises the following: a reactor(1) formed with a single aeration tank, an anoxic tank, an aeration tank, or an anaerobic tank, receiving wastewater for purifying; a diffuser(3) inserting air to the aeration tank(1b) using a blower(2); and a film module(5) formed with an osculum caliber metal layer(4) on the upper side of the diffuser.

Description

Gravity flow MBR for treatment of wastewater using metal membrane with macro pore size}

The present invention relates to a sewage / wastewater treatment system, and more specifically, to a natural hydrostatic pressure exclusion system having a separation membrane made of metal having a tool diameter of 10 μm or more in an aeration tank instead of a gravity settling tank for solid-liquid separation of activated sludge method. The present invention relates to a natural excretion type sewage / wastewater treatment system using a large-diameter metal membrane which can obtain a high quality treatment water, minimize the size of the reactor, and solve the clogging of the separator by a physical washing method.

In general, the activated sludge method is applied and operated for most of the conventional sewage / wastewater treatment, but these biological treatment processes are composed of an aeration tank for culturing microorganisms and a precipitation tank for solid-liquid separation. The sedimentation tank must be separated from the activated sludge (solids) and treated water in order to obtain clean treated water because the sewage / wastewater and microorganisms to be treated introduced from the aeration tank are completely mixed.

Therefore, the conventional activated sludge process requires a gravity solid-liquid separation facility, which is mostly referred to as a secondary sedimentation tank, and a large reaction tank and a secondary sedimentation tank should be provided for this purpose. When problems such as swelling or pin flocks occur in the sludge of the reactor, The reactor does not operate stably and thus does not obtain good treated water.

Therefore, in recent years, in order to reduce the site by maintaining high concentration of microorganisms in the reaction tank and to improve the treatment efficiency of the pollutants in the wastewater, the microfilter or ultrafilter in the form of hollow fiber membrane or flat membrane of polymer organic material in the aeration tank. Membrane Separation Bioreactor (MBR) process has been developed and applied by applying the method of immersing the water and forcing the treated water to a constant pressure using a pump. Here, the pore of the separator is in the range of 0.001 ㎛ ~ 10 ㎛.

In the membrane separation bioreactor process as described above, an organic membrane mainly made of a polymer material is used as the separation membrane, and the separation membrane is generally used to prevent fouling by inhibiting particle adsorption and cake formation on the surface as much as possible. It is mainly used to maintain the membrane permeation flow rate by minimizing particle adsorption and cake formation by reducing the concentration polarization phenomenon and giving shear force by forming water flow in the aeration tank by using aeration method. Operating processes such as a 10 minute run, a 2 minute rest, and the like to maintain. At this time, the solids including the microorganisms in the reaction tank is attached to the membrane surface. In order to prevent the adhesion of the solids to the membrane surface, a method of controlling the blockage by generating water flow using aeration in the reaction tank is mainly applied.

Nevertheless, the conventional membrane separation bioreactor process can not fundamentally solve the blockage caused by membrane contamination generated during long time operation, and separates the membrane outside the reactor to clean it using chemical hypochlorous acid, etc. A backwashing method for injecting a small amount of cleaning agent in the reverse direction of the treated water to the separator has been developed and applied.

Most of these conventional methods use an organic membrane made of a polymer material, and due to the characteristics of the polymer material, it is difficult to have a pore size of 10 μm or more, and it is easy to tear due to its weak durability. Therefore, to separate the sludge and the treated water in the reactor by using a pump to maintain a constant pressure to remove the treated water to a certain amount, it is not possible to apply the backwashing method of blowing air from the inside of the membrane to the outside.

In particular, the organic membrane made of polymer has the disadvantage of physical cleaning that directly wipes the surface of the membrane with a cleaning rod or brush due to its material characteristics. Therefore, it is difficult to clean when the membrane is clogged. Can be.

Recently, a method of dissolving ozone gas in membrane filtration water by applying a metal membrane to prevent fouling of the membrane and a cake layer on the membrane surface has been developed to maintain a constant membrane permeation flow rate. An apparatus is required, and the tool diameter of the metal film does not overcome the limitations of the existing method of forcibly sucking the filtered water to about 0.2 μm, which is not economical.

Accordingly, an object of the present invention is to provide a separation membrane made of metal having a tool diameter of 10 μm or more in the aeration tank instead of the gravity settling tank for solid-liquid separation to separate sludge (solid matter) and treated water in the bioreactor while maintaining a high flux. It is to provide a natural exclusion type sewage / wastewater treatment system using a large-diameter metal membrane that can be easily separated and excluded by natural head pressure without power.

In addition, another object of the present invention is to reduce the pump and power costs for the treatment water removal by using a separation membrane having a large tool diameter and to secure a high permeation flux (Flux) to reduce the idle time compared to the filtration (suction) time by the membrane. It is to provide a natural discharge type sewage / wastewater treatment system using a large-diameter metal membrane that can shorten and provide easy physical washing directly to the membrane.

In addition, another object of the present invention is to fill a functional carrier capable of selectively treating phosphorus, nitrogen, and other harmful pollutants in the membrane to biologically treat organic matter, nitrogen, phosphorus, and other contaminants in sewage / wastewater. In addition to the efficiency, it is possible to provide a natural sewage / wastewater treatment system using a large-diameter metal membrane that can be further removed.

Meanwhile, the object of the present invention is not limited to the above-mentioned objects, and other objects not mentioned can be clearly understood by those skilled in the art from the following description.

To this end, according to the present invention, in the wastewater / wastewater treatment system in which the wastewater / wastewater flows into a single aeration tank, or an anaerobic tank and an aeration tank, or a reaction tank combined with an anaerobic tank, anoxic tank, and aeration tank, is purified. An diffuser into which air is injected; A membrane module composed of a metal membrane is positioned on the upper part of the diffuser, and the sludge and the treated water are separated through the membrane module in the aeration tank, and the treated water is removed from the reactor by the natural head pressure. Natural sewage / wastewater treatment systems are provided.

Here, the metal film is made of a metal material such as stainless steel or brass, it is preferable that the tubular (Tubular) or flat plate (Plate) is made to be selectively installed in the reaction tank.

In addition, the metal film preferably has a plurality of pores having a tool diameter of 10 μm to 100 μm.

It is also preferred that the metal film is filled with a catalyst or a carrier for further removing phosphorus, nitrogen and other contaminants as necessary.

In addition, the film cleaning is blocked by the pipe for injecting air into the reaction tank and open the pipe connected to the metal film to enter the inside of the metal film by using the air supplied from the blower to discharge the air from the inside of the metal film to the metal It is desirable to allow the materials attached to the membrane surface to be washed off periodically.

In addition, it is also preferred that the cleaning rod or brush is installed to wash the solid attached to the surface of the metal film.

Therefore, according to the present invention, the sedimentation tank is omitted as compared to the conventional sewage / wastewater treatment system, and the metal membrane having a tool diameter of about 10 μm to 100 μm is provided in the aeration tank, thereby providing a higher concentration than the conventional biological sewage / wastewater treatment method. MLSS can be maintained and high-quality solid-liquid separation can be obtained even if the structure of the sedimentation tank is omitted to obtain a high quality treated water.

In addition, compared to the conventional MBR method using an organic membrane or a metal membrane of a microporous polymer, a high pump flux and high flux can be obtained without requiring a separate pump and power to remove treated water, and a separate device is used for blocking the membrane. It can be easily solved in the reactor without the physical and can enable more economical and stable sewage / wastewater treatment.

In addition, the filling of the functional catalyst or the carrier inside the membrane is easy to remove in addition to the biological treatment efficiency of the contaminants to be treated without any additional reactor or device.

On the other hand, the effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the description of the claims.

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

1 is a view schematically showing a natural sewage type sewage / wastewater treatment system using a large-diameter metal film according to a preferred embodiment of the present invention, and FIG. 2 is backwashing the metal film with air in the sewage / wastewater treatment system of FIG. 1. 3 is a view showing a method for determining, and FIG. 3 is a view showing a method of continuously washing a metal film with a washing brush in the wastewater / wastewater treatment system of FIG. 1.

As shown in Figures 1 to 3, the natural excrement type sewage / wastewater treatment system using a large diameter metal membrane according to a preferred embodiment of the present invention, first, after the basic pretreatment such as pH adjustment, suspended solids removal / The waste water enters the reaction tank 1 which is combined with a single aeration tank or anoxic tank maintained at a constant sludge concentration (MLSS) and aeration tank or anaerobic tank, anoxic tank and aeration tank depending on the contaminants to be treated.

The sewage / wastewater introduced into the reaction tank 1 stays in the reaction tank 1 for a predetermined time, at which time contaminants contained in the sewage / waste water are decomposed and absorbed by microorganisms and purified.

Here, it is preferable that the metal membrane module for filtering the treated water purified as the reaction tank 1 is installed in the aeration tank 1b.

The aeration tank 1b is supplied with oxygen through the diffuser 3 through which air is injected from the brower 2 in order to supply oxygen to the microorganisms, to mix, and to give a shear force to the membrane surface to prevent the solids from adhering to the membrane surface. A membrane module 5 composed of a metal film 4 is provided on the diffuser 3 and the sludge and the treated water are separated in the aeration tank 1b through the membrane module 5, and the treated water is reacted by the natural head pressure. (1) It is filtered out.

In addition, the sludge of the aeration tank 1b is continuously transferred to the anaerobic tank 1a or the anaerobic tank 1a by a conveying pump 6 in order to maintain a constant sludge concentration of the entire aeration tank 1b, and part of the sludge concentration is It is disposed of as excess sludge for maintenance.

In this case, the metal film 4 is made of tubular or flat plate and is easily selected and installed inside the aeration tank 1b. In order to maintain a constant permeability of the metal film, If cleaning or temporary backwashing is required, the pipe (8b) of the pipe connected to the metal film (4) is opened by the valve (8a), which blocks the air to the aeration tank (1b) during the rest period, and opens the blower (2). The air supplied from) is introduced into the metal film 4 and the air is discharged from the inside of the metal film 4 to the outside, so that the solids attached to the surface of the metal film 4 are removed and washed.

In addition, instead of the method of backwashing with air, a cleaning rod or brush 9 is installed on the surface of the metal film 4 to prevent the metal film 4 from being clogged, so that the surface of the metal film 4 is washed. good. At this time, the cleaning rod or brush 9 is preferably rotated by a separate rotating member (not shown) to clean the surface of the metal film (4).

The metal film 4 is made of metal such as stainless steel and brass, and has heat resistance, chemical resistance, acid resistance and alkali resistance, and has a plurality of pores having a size of 10 to 100 μm, and when the tubular material is manufactured in a tubular shape, the diameter is 1. ~ 10cm and the length is in the range of 10 ~ 200cm, the flat membrane is in the range of 10 ~ 100cm, 10 ~ 1,000cm in height, the support is usually installed in the membrane to maintain the shape of the membrane.

Here, a catalyst or carrier may be filled in the inner space of the metal film 4 to further remove phosphorus, nitrogen, and other contaminants.

Hereinafter, the operation and effects of the natural exclusion type sewage / wastewater treatment system using the large-diameter metal membrane according to the preferred embodiment of the present invention will be described in detail.

First, in order to prevent clogging of the metal film 4 by a controller (not shown) or an input unit (not shown), the driving is controlled in a period of 8 to 10 minutes of operation (suction) and 1 to 2 minutes of rest.

At this time, periodic backwashing is performed to exclude stable permeate flow rate, and the pipe 8b of the pipe connected to the metal film 4 is blocked by the valve 8a and the pipe for injecting air into the aeration tank 1b during the rest period. ) Is opened and air supplied from the brower 2 is introduced into the metal film 4 and air is discharged from the inside of the metal film 4 to the outside, and solids attached to the surface of the metal film 4 are washed away. . After the rest period is over again, the valve (8b) is locked and the valve (8a) is opened, the air by the brower (2) is supplied to the diffuser to supply oxygen to the microorganisms and to form water flow, and the treated water is filtered through a metal film Head pressure is excluded outside the reactor.

An embodiment of the sewage / wastewater treatment using the natural wastewater type sewage / wastewater treatment system using the large diameter metal membrane as described above will be described with reference to Tables 1 to 3 below.

division Specification (mm) Etc Anaerobic 450L × 1000W × 1000H Top Stirrer Installation Aeration tank 1000L × 1000W × 1000H Lower diffuser and follower installation SUS membrane module 60 ID x 500 H x 54 Total effective membrane area: 4.2m ²

Table 1. Reactor Specifications First, as shown in Table 1, the reaction tank 1 having a work treatment of 2 m 3 / day capacity was manufactured to have the above specifications and configurations by the combination of the oxygen-free tank 1a and the aeration tank 1b. It was installed in the sewage treatment plant and operated using sewage. At this time, the used metal film 4 was made of stainless steel with a real pore of about 30 μm, where the pore size was the diameter of the planted sludge. PSA was measured to have a size of about 35㎛ to correspond to this.

division Anaerobic Aeration tank Reactor size 300 L 700 L HRT 2.4 to 3.6 hr 5.6-8.4 hr MLSS 5,000-6,000 mg / L 5,000-6,000 mg / L DO 0.2 mg / L or less 3.0 mg / L or more Bounce rate 3Q Interlude 4 to 5 KPa

Table 2. Reactor Operation Conditions

Item unit Influent Treated water Removal rate (%) BOD ₅ mg / L 121.8 6.9 94.3 CODcr mg / L 199.6 12.2 93.9 SS mg / L 99.6 1.0 99.0 T-N mg / L 44.6 12.8 71.3 T-P mg / L 5.2 1.4 73.1

Table 3. Experimental Results In addition, as shown in Table 2 and Table 3, as a result of the continuous operation control, the sludge concentration (MLSS) of the reactor 1 was maintained at about 6,000mg / L. The differential pressure between the metal film 4 was about 4 ~ 5KPa, the permeation flow rate was about 40LMH (L / m 2 · h). In addition, BOD ₅ and CODcr of organic matters showed 94% of treatment efficiency, 71% of total nitrogen and 73% of phosphorus. In addition, despite the MLSS is maintained at about 6,000mg / L in the reactor (1), the SS concentration of the treated water showed an average value of 1.0mg / L. In addition, it was continuously operated by natural head pressure without a pump for forced removal of the treated water, the operation was performed with a stable permeate flow rate without clogging the membrane by the air washing method, a physical cleaning method.

Therefore, according to the present invention, a metal film having a tool diameter of about 10 μm to 100 μm is provided in the aeration tank as compared to the conventional sewage / wastewater treatment system, thereby maintaining a higher concentration of MLSS compared to the conventional biological sewage / wastewater treatment method. In addition, even if the configuration of the sedimentation tank is omitted, high-efficiency solid-liquid separation is possible to obtain high quality treated water.

In addition, compared to the conventional MBR method using a microporous polymer membrane, it is possible to obtain a high permeability (Flux) without the need for a separate pump and power to remove treated water. The physical method of cleaning the surface with a brush can be easily solved in the reactor, allowing for more economical and stable sewage / wastewater treatment.

While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains have various permutations and modifications without departing from the spirit or essential features of the present invention. It is to be understood that the present invention may be practiced in other specific forms, since modifications may be made. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

1 is a view schematically showing a natural exclusion type sewage / wastewater treatment system using a large-diameter metal film according to a preferred embodiment of the present invention;

FIG. 2 is a view showing a method for backwashing a large diameter metal film with air in the sewage / wastewater treatment system of FIG. 1; FIG.

3 is a view showing a method of continuously cleaning a large diameter metal film with a washing brush in the sewage / wastewater treatment system of FIG.

* Drawing reference *

1: Reactor 1a: Anaerobic tank or anoxic tank

1b: Aeration tank 2: Brow

3: diffuser 4: metal film

5 Membrane Module 6 Transfer Pump

7: agitator 8a, 8b: valve

9: brush

Claims (5)

In a sewage / wastewater treatment system in which a wastewater / wastewater is introduced into a single aeration tank, or an anaerobic tank and an aeration tank, or an anaerobic tank, an anaerobic tank, and an aeration tank is introduced and purified. In the aeration tank 1b of the reactor 1 An air diffuser 3 through which air is injected from the brower 2; A membrane module 5 composed of a large diameter metal film 4 is provided on the diffuser 3; The sludge and the treated water are separated in the aeration tank 1b through the membrane module 5, and the treated water is naturally discharged to the outside of the aeration tank 1b by natural head pressure. Natural excretion type sewage / wastewater treatment system using a large diameter metal membrane, characterized in that for applying a physical cleaning method to periodically remove the solids attached by a cleaning rod or brush. The method of claim 1, wherein the metal film 4, Has a metal material such as stainless steel or brass, It has a plurality of pores with a tool diameter of 10 ~ 100㎛ size is made of tubular or flat plate (Plate) and the natural exclusion type using a large-diameter metal film, characterized in that the selective installation in the interior of the reaction tank (1) / Wastewater treatment system. 3. The natural excretion type sewage / wastewater treatment system using a large-diameter metal film according to claim 2, wherein the metal film (4) is filled with a catalyst or a carrier for removing phosphorus, nitrogen and other contaminants. The air supplied from the blower (2) according to claim 1, wherein the backwashing block blocks the pipe for injecting air into the aeration tank (1b) and opens the pipe connected to the metal film (4). Natural excretion type sewage / wastewater treatment system using a large-aperture metal film, which is introduced into the metal film 4 so that air is discharged from the inside of the metal film 4 to the outside, and solids attached to the surface of the metal film 4 are washed away. . The method of claim 2, wherein the washing rod or brush (9) is installed on the surface of the metal film 4, the natural exclusion type using a large-diameter metal film, characterized in that to clean the surface of the membrane while continuously reciprocating up and down. Wastewater treatment system.

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