KR102300414B1 - High efficiency advanced wastewater treatment system - Google Patents

Abstract

The present invention relates to a high-efficiency wastewater membrane separation treatment system. More specifically, the present invention relates to a high-efficiency wastewater membrane separation treatment system that improves the removal efficiency of total phosphorus, total nitrogen and dissolved organic matter by arranging a bioreactor in the order of an anaerobic tank, full aeration tank, oxygen reduction tank, anoxic tank and membrane separation tank, improves the denitrification efficiency in an anoxic tank by having an inlet line for introducing raw water and an external carbon source into the anoxic tank, and improves the oxygen transfer rate to a full aeration tank by installing an agitator for performing agitation and aeration functions in the full aeration tank.

Description

High efficiency wastewater membrane separation treatment system {High efficiency advanced wastewater treatment system}

The present invention relates to a high-efficiency wastewater membrane separation treatment system, and more particularly, by arranging the bioreactor in the order of an anaerobic tank, full aeration tank, oxygen reduction tank, anoxic tank and membrane separation tank to improve the removal efficiency of total phosphorus, total nitrogen and dissolved organic matter The denitrification efficiency of the anaerobic tank is improved by providing an inlet line for dividing the raw water and the external carbon source into an anaerobic tank and an anaerobic tank, and an agitator is installed in the full aeration tank to stir the mixture, and also to inject air without a separate aeration device. It relates to a high-efficiency wastewater membrane separation treatment system that can.

In general, sewage, wastewater and sewage contain various pollutants such as phosphorus, nitrogen, organic substances, and suspended matter, and if they are discharged without proper treatment, they cause water pollution and eutrophication, which adversely affects the ecosystem. , these contaminants are discharged or reused after being treated with advanced biological treatment methods by microorganisms.

The A2O method, which is a biological advanced treatment method with the longest history, is a method to remove contaminants in wastewater by arranging bioreactors in the order of anaerobic tank, anoxic tank, aerobic tank, and sedimentation tank. Currently, various advanced treatment methods have been developed based on this. is becoming Since this advanced biological treatment method basically uses microorganisms, the degree of activation of microorganisms in each bioreactor is an important factor influencing the treatment efficiency of contaminants.

In particular, nitrogen is removed through nitrification and denitrification. Since organic carbon is used in the denitrification process, an appropriate amount of organic carbon must be supplied to the bioreactor in which denitrification is performed.

Accordingly, in Korean Patent Application Laid-Open No. 10-2017-0109321, the bioreactor is arranged in the order of the first anoxic tank, anaerobic tank, aerobic tank, second anoxic tank, and separation membrane tank, and an external carbon source is injected into the second anoxic tank to denitrify in the second anaerobic tank Although the technology to improve the efficiency has been presented, when an external carbon source is used in this way, it is difficult to maintain a constant C/N ratio in the anoxic tank, and there is a possibility of additional contamination due to an external carbon source remaining in the effluent without being used for the denitrification reaction. In addition, there are problems such as an increase in operating costs due to an enormously expensive external carbon source.

Meanwhile, as the total phosphorus standard in effluent from public sewage treatment facilities has been strengthened to 0.2-0.5 mg/L or less by region, research and development is being conducted on a wastewater treatment method that can increase phosphorus removal efficiency. Since the removal efficiency is low, there is a need to develop a technology for a process capable of increasing the phosphorus removal efficiency while reducing the operating cost.

Publication No. 10-2017-0109321 (published on September 29, 2017)

In the present invention, the bioreactor is arranged in the order of an anaerobic tank, full aeration tank, oxygen reduction tank, anoxic tank and membrane separation tank to improve the removal efficiency of total phosphorus, total nitrogen and dissolved organic matter, and to divide and introduce raw water and external carbon sources into an anaerobic tank and anoxic tank An inlet line is provided to provide a high-efficiency wastewater membrane separation treatment system that improves the denitrification efficiency of an anoxic tank.

In addition, a full aeration tank is installed in front of the anoxic tank to split the inflow of ammonia nitrogen, and the divided inflow of nitrified nitrate nitrogen is introduced into the anaerobic tank, thereby improving the nitrogen removal efficiency and reducing the amount of internal transport at the rear end compared to the existing method. We want to cut energy costs by reducing it by more than half

In addition, in the present invention, a high-efficiency wastewater membrane separation treatment system is provided that enables smooth stirring by installing and operating an agitator in the full aeration tank, and at the same time, air is injected without a separate aeration device by Bernoulli principle to obtain a high oxygen transfer rate. want to

The high-efficiency wastewater membrane separation treatment system of the present invention for achieving the above object includes: an anaerobic tank in which at least a portion of raw water is divided and introduced, and phosphorus elution reaction occurs in an anaerobic atmosphere; a full aeration tank in which the treated water treated in the anaerobic tank is introduced, and excessive phosphorus intake and nitrification reaction occur in an aerobic atmosphere; an oxygen reduction tank in which the treated water treated in the full bombardment tank is introduced to remove free oxygen; an anoxic tank in which the treated water and raw water treated in the oxygen reduction tank are introduced, and a denitration reaction occurs in an anoxic atmosphere; and a membrane separation tank including a separation membrane unit for filtering the treated water into which the treated water treated in the anaerobic tank is introduced.

A stirrer is installed in the full aeration tank, the mixed solution in the full aeration tank is stirred by the stirrer, and external air may be introduced and aerated.

The stirrer, a rotating rod vertically disposed with respect to the bottom surface of the full-width gas tank; a wing unit connected to the rotating rod to cause a flow motion in the mixed solution; and a connecting pipe connected to the rotating rod and the wing portion, but formed by an open boundary portion connected to the rotating rod and the wing unit.

The rotating rod, the wing portion, and the connecting tube are formed in the form of a tube with an empty interior, and may be provided to communicate with each other.

One end of the rotating rod may be in communication with the outside air, and the other end may be sealed.

The wing portion may be provided in a form in which a cross section of the center has a smaller area than a cross section of both ends.

Further comprising: an external carbon source injection device for injecting an external carbon source into the anaerobic tank, wherein the external carbon source injection device controls the amount of the external carbon source injected according to the C/N ratio of the anaerobic tank measured in real time, and at the same time the quality of raw water and the quality of the effluent finally discharged from the high-efficiency wastewater membrane separation treatment system; It is possible to adjust the amount of the external carbon source injected according to the quality of at least one or more of the water.

a first line through which the raw water is introduced into the anaerobic tank; a second line through which the external carbon source is introduced into the anaerobic tank; and a control unit for controlling the opening rates of the first line and the second line.

The control unit, the anaerobic tank water quality; Alternatively, the opening rate of the input first line and the second line may be adjusted according to the flow rate of the raw water, the quality of the water and the flow rate of the treated water, and the quality of the water.

A first return line for returning the mixed solution in the anaerobic tank to the anaerobic tank; may be provided.

A second conveying line for conveying the mixed solution in the membrane separation tank to the full aeration tank; may be provided.

The separation membrane unit is installed so as to be immersed in the mixed solution in the membrane separation tank, and includes a plurality of separation membrane elements, so that solid substances of a predetermined size or more contained in the mixed solution by the negative pressure generated inside the separation membrane element are filtered treated water , and an aeration device may be provided at the lower end of the separation membrane unit.

A backwashing device connected to the separation membrane unit may be provided.

The diffuser may include: first and second diffusers arranged in parallel and spaced apart from each other by a predetermined distance; a third diffuser having one end communicating with one end of the first diffuser through an elbow and the other end communicating with a second diffuser; and a fourth diffuser disposed to be spaced apart from the third diffuser by a predetermined distance, one end of which is disposed to communicate with the first diffuser, and the other end of which is arranged to communicate with the second diffuser; The holes are formed to be spaced apart by a predetermined distance, and air may be introduced through the other end of the first diffuser and one end of the second diffuser.

The diffuser may include: a sludge discharge pipe communicating with the other end of the second diffuser; and a valve for controlling the opening and closing of the sludge discharge pipe.

The high-efficiency wastewater membrane separation treatment system of the present invention can improve the removal efficiency of total phosphorus, total nitrogen and dissolved organic matter by arranging the bioreactor in the order of an anaerobic tank, full aeration tank, oxygen reduction tank, anoxic tank and membrane separation tank.

In addition, it is equipped with an inlet line for introducing raw water and an external carbon source into the anoxic tank, and by automatically adjusting the inflow of raw water and external carbon source, the denitrification efficiency of the anaerobic tank can be improved, operating costs can be reduced, and the amount of external carbon source can be reduced This can be reduced to prevent further contamination by runoff.

In addition, as the agitator is installed and operated in the full bombardment tank, the mixing in the full bombardment tank is smoothly stirred and at the same time external air can be introduced by the Bernoulli principle. The cost of power required for injection can be reduced.

In addition, it is possible to minimize changes in the water quality of the effluent due to environmental factors such as changes in raw water quality or water temperature and the proliferation of filamentous bacteria by improving the filtration rate of solids including microorganisms by providing a membrane separation tank at the end of the membrane separation tank. It is possible to prevent clogging of the separation membrane by providing an automatic backwashing system that automatically backwashes the separation membrane.

In addition, by automatically or manually opening and closing the sludge discharge pipe valve of the aeration pipe, it is possible to prevent the accumulation of sludge in the aeration pipe and a reduction in the amount of discharged air due to this, and smooth air cleaning of the separation membrane is possible through the aeration pipe, so membrane separation treatment Long-term normal operation of the system can be promoted.

1 is a block diagram of a high-efficiency wastewater membrane separation treatment system according to an embodiment of the present invention.
2 is a view showing a stirrer according to an embodiment of the present invention.
3 is a view illustrating a principle in which air is injected by a stirrer according to an embodiment of the present invention.
4 is a flowchart illustrating a control method based on the C/N ratio of the anaerobic tank and the quality of raw water among the control methods of the first line and the second line according to an embodiment of the present invention.
5 is a flowchart illustrating a control method based on the C/N ratio of the anaerobic tank and the water quality of the effluent among the control methods of the first line and the second line according to an embodiment of the present invention.
6 is a diagram schematically illustrating an air diffuser according to an embodiment of the present invention.

Hereinafter, before describing in detail through preferred embodiments of the present invention, terms or words used in the present specification and claims should not be construed as being limited to conventional or dictionary meanings, and meanings consistent with the technical spirit of the present invention and should be interpreted as a concept.

Throughout this specification, when a part "includes" a certain component, it means that other components may be further included rather than excluding other components unless otherwise stated.

In order to clearly explain the invention proposed in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification. In addition, "unit" described in the specification means one unit or block that performs a specific function.

Hereinafter, an embodiment of the present invention will be described. However, the scope of the present invention is not limited to the following preferred embodiments, and those skilled in the art can implement various modified forms of the contents described herein within the scope of the present invention.

1 is a block diagram of a high-efficiency wastewater membrane separation treatment system according to an embodiment of the present invention.

Referring to FIG. 1 , the high-efficiency wastewater membrane separation treatment system of the present invention is arranged in the order of an anaerobic tank 100 , full aeration tank 200 , oxygen reduction tank 300 , anoxic tank 400 and membrane separation tank 500 . and a bioreactor, and the untreated water introduced into each bioreactor may be maintained in the bioreactor for a predetermined time, and then may be introduced into the bioreactor disposed at the rear end by gravity.

In more detail, the high-efficiency wastewater membrane separation treatment system of the present invention includes: an anaerobic tank 100 in which at least a portion of raw water is dividedly introduced, and phosphorus elution reaction occurs in an anaerobic atmosphere; The aeration tank 200 in which the treated water treated in the anaerobic tank 100 is introduced, and excessive phosphorus intake and nitrification reaction by microorganisms occur in an aerobic atmosphere; an oxygen reduction tank 300 in which the treated water treated in the full aeration tank 200 is introduced to remove free oxygen; an anoxic tank 400 in which the treated water treated in the oxygen reduction tank 300, treated water and raw water are introduced, and a denitration reaction occurs in an anoxic atmosphere; and a membrane separation tank 500 including a separation membrane unit for filtering the treated water into which the treated water treated in the anoxic tank 400 is introduced.

The anaerobic tank 100 is a bioreactor in which raw water such as sewage, wastewater, sewage and rainwater is introduced and phosphorus is eluted by microorganisms in an anaerobic atmosphere, and the phosphorus released here is excessively ingested by microorganisms in the full bombardment tank 200 . becomes and is removed However, if the content of nitrate nitrogen or nitrite nitrogen contained in the mixed solution in the anaerobic tank 100 is high, the phosphorus elution reaction in the anaerobic tank 100 is inhibited, so raw water with a high content of nitrate nitrogen or nitrite nitrogen When introduced, there is a problem that the total phosphorus removal efficiency is lowered.

Accordingly, in the high-efficiency wastewater membrane separation treatment system of the present invention, free oxygen is primarily removed in the oxygen reduction tank 300, and nitrate nitrogen and nitrite nitrogen are removed by denitrification in the subsequent anoxic tank 400. By returning to the anaerobic tank 100, the phosphorus elution reaction is activated.

In the pre-aeration tank 200, the treated water treated in the anaerobic tank 100 of the previous stage is introduced, phosphorus in the treated water is removed by excessive phosphorus intake of phosphorus-accumulating microorganisms in an aerobic atmosphere, and ammonia is produced by the nitrification reaction of the nitrifying microorganisms. A reaction occurs in which nitrogen is oxidized to nitrite or nitrate nitrogen. The nitrite nitrogen or nitrate nitrogen produced here is removed in the anoxic tank 400 to be described later.

A stirrer 210 for uniformly and smoothly mixing the mixed solution inside the full bombardment tank 200 is installed in the full bombardment tank 200 . Specifically, the agitator 210 is installed and operated to smoothly agitate the mixed solution in the full bombardment tank 200, maintain a homogeneous suspended state of microorganisms, and supply oxygen necessary for respiration of microorganisms, through this, The wastewater membrane separation treatment system of the present invention can obtain a high oxygen transfer rate with only a small amount of air by injecting external air into the mixed solution without a separate air injection device.

Hereinafter, the stirrer 210 installed in the full bombardment tank 200 of the present invention will be described in detail with reference to FIG. 2 .

2 is a view showing a stirrer 210 according to an embodiment of the present invention.

The agitator 210 includes a rotary rod 211 disposed perpendicular to the bottom surface of the full-width gas tank 200; a wing portion 212 connected to the rotating rod 211 to cause a flow motion in the mixed solution; and a connecting pipe 213 that connects the rotating rod 211 and the wing portion 212, but is formed by opening a boundary portion connected to the rotating rod 211 and the wing portion 212.

Therefore, as the agitator 210 rotates, the fluid flow is generated by the wing 212 , so that the mixed solution in the full bombardment tank 200 can be uniformly and smoothly stirred.

The rotating rod 211, the wing portion 212, and the connecting pipe 213 are formed in the form of an empty tube and communicate with each other, and one end of the rotating rod 211 communicates with the outside air and the other end is formed to be sealed. do. Accordingly, the air introduced into the rotating rod 211 through one end of the rotating rod 211 is transferred to the wing unit 212 through the connecting pipe 213 and flows out through the end of the wing unit 212 .

At this time, the wing portion 212 is formed in the form of a tube, and has a venturi pipe shape in which a cross section of the center is relatively smaller than a cross section of both ends. Therefore, as the agitator 210 rotates, a sudden pressure drop occurs inside the wing portion 212, and accordingly, external air is introduced into the agitator 210 through one end of the rotating rod 211 and the wing portion ( 212), and air may be injected into the mixed solution in the full bombardment tank 200.

The wing portion 212 may be formed in a tubular shape, and the longitudinal central axis of the wing portion 212 may be inclined at a predetermined angle with respect to the rotation direction of the rotating rod 211 . Preferably, the front end 212a of the wing 212 may be inclined to be disposed at the upper end relatively than the rear end 212b. As the wing 212 is formed in this way, the rotating rod 211 rotates. When the mixed solution of the full bombardment tank 200 flows into the tube of the lower wing part 212, a spiral flow of the mixed solution occurs by the wing part 212 at the same time, thereby enabling more uniform and smooth mixing.

The wing portion 212 includes a front end portion 212a, a center portion 212c, and a rear end portion 212b, and a cross-section of the center portion 212c includes a front end portion 212a and a rear end portion 212b. It is formed smaller than the cross-section, and the cross-sectional area of the central portion 212c is formed uniformly.

At this time, the front end 212a and the rear end 212b are formed to decrease in cross-section toward the center 212c, and the maximum cross-section of the front end 212a is greater than the maximum cross-section of the rear end 212b. is formed

In addition, the length and diameter of the front end (212a) is formed longer and larger than the length and diameter of the rear end (212b), the flow rate when the fluid flowing into the front end (212a) flows out to the rear end (212b) As this increases, the stirring effect in the full bombardment tank 200 may be improved. As the concentration and viscosity of the mixed solution in the full bombardment tank 200 are high, the difference between the length and the diameter of the tube is increased to further enhance the stirring effect.

Hereinafter, a principle in which air is injected by a stirrer according to an embodiment of the present invention will be described in detail with reference to FIG. 3 .

As described above, the wing portion 212 of the stirrer 210 installed in the full-width air tank 200 of the present invention has a venturi pipe type in which the cross section of the central portion 212c has a relatively narrower area than the cross-section of both ends. has That is, the cross-sections of one side and the other side of the wing portion 212 have a relatively larger size than the cross-section of the central portion 212c, so that air can be injected into the mixed solution in the full-width gas tank 200,

More specifically, the rotating rod 211 of the stirrer 210 is in the form of a tube with an empty interior, and is formed such that one end communicates with the outside air and the other end is sealed. The rotating rod 211 is provided with a plurality of wing portions 212 through the connecting pipe 213 .

The connecting tube 213 also has a hollow tube shape. In addition, the connecting pipe 213 is connected to the rotating rod 211 and the wing portion 212, and the connecting tube 213 is connected to each other so that the boundary portions connected to the rotating rod 211 and the wing 212 are also communicated with each other. , The rotating rod 211, the wing portion 212 and the connecting pipe 213 are fixed to each other in the form of internal communication.

Therefore, when the rotating rod 211 rotates, the wing portion 212 in the form of a venturi tube attached to the rotating rod 211 rotates together. once introduced That is, as the wing portion 212 has a venturi tube shape, the mixed solution introduced through the front end portion 212a having a larger cross-sectional area is transferred to the central portion 212c having a narrower cross-sectional area, and the flow rate according to Bernoulli's principle is accelerated and at the same time the pressure is rapidly reduced.

Air is injected through one end of the rotating rod 211 by this decompression phenomenon, and the injected air is the central portion 212c of the wing portion 212 having a venturi tube shape through the rotating rod 211 and the connecting pipe 213 ). In this way, the air sucked into the central portion 212c may be aerated into the mixed solution through the rear end portion 212b of the wing portion 212 . In other words, the fine air mixed with the mixed solution and discharged through the rear end 212b of the wing part 212 having the venturi tube shape rises in a spiral shape by the inertial force and the flow of the mixed solution, thereby causing air bubbles in the mixed solution residence time and oxygen transfer rate are increased.

Therefore, according to the present invention, efficient aeration is possible only by injecting a small amount of air through the stirrer 210 for agitating the mixed solution in the full aeration tank 200, and there is no need to install or operate a separate aeration device, thereby reducing power costs. can

In addition, the present invention provides a separate aeration device at one end of the rotating rod 211 of the stirrer 210, even in a large-scale reaction tank (eg, sewage treatment plant, etc.) in which sufficient aeration is difficult only by driving the stirrer 210 alone. It can be installed and applied, and in this case, the oxygen transfer rate during aeration through the agitator 210 is very high, so there is an advantage that smooth aeration is possible only by supplying a much smaller amount of air than when a general aeration device is installed. Next, with reference to FIG. 1 again, the high-efficiency advanced wastewater treatment system of the present invention will be described.

The oxygen reduction tank 300 is a bioreactor in which the treated water treated in the full-bombardment tank 200 of the previous stage is introduced to remove free oxygen in the treated water, and the free oxygen is removed by respiration of microorganisms or volatilization into the atmosphere. , by removing a large amount of free oxygen injected in the full aeration tank 200, a smooth denitrification action is made in the anoxic tank 400 at the rear stage, and consequently, the total nitrogen removal efficiency is improved.

The anaerobic tank 400 is a bioreactor in which the treated water and raw water treated in the oxygen reduction tank 300 of the previous stage are introduced, and a reaction in which nitrogen in the treated water is removed by denitrification microorganisms in an anaerobic atmosphere occurs.

Since the denitrification microorganisms present in the anoxic tank 400 perform a denitrification reaction using organic matter, it is preferable that the concentration of organic matter in the anoxic tank 400 is higher, and in general, the denitrification reaction in the anoxic tank 400 is a dissolved organic matter for nitrogen. The higher the C/N ratio, which is the ratio of , the higher the efficiency. In this case, the concentration of dissolved organic matter for calculating the C/N ratio is based on the biological oxygen demand (BOD).

However, since the treated water having a low organic substance concentration is introduced into the anoxic tank 400 by the reaction in the full-bombardment tank 200 previously, in order to increase the organic substance concentration of the anoxic tank 400, the means for inputting the raw water into the anaerobic tank 400 is The first line 10 branched from the raw water inlet line introduced into the anaerobic tank 100 may be provided by this means.

In addition, when it is difficult to induce a sufficient denitrification reaction because the concentration of organic matter in raw water is low, an external carbon source injection device 410 and a second line 20 for injecting an external carbon source into the anoxic tank 400 may be further provided. .

A water quality sensor for automatic injection of an external carbon source may be selected and installed in at least one of the inflow line of the inflow source water and the discharge line of the outflow water. It can be selected in consideration of the installation conditions including the like, and the variation of the influent water quality with the passage of time.

As the external carbon source, a known material may be used, for example, methanol, ethanol, methane, acetate, ketone, molasses-saccharide, brewing-distillate, etc. may be used, and preferably methanol may be used.

The first line 10 and the second line 20 are provided to increase the dissolved organic matter concentration of the anaerobic tank 400 as described above, and the first line 10 to more efficiently control the dissolved organic matter concentration ) and the opening rate of the second line 20 may be adjusted by the control unit. Specifically, it is adjusted according to the water quality of the anaerobic tank 400, and at the same time adjusted according to the quality and flow rate of at least one of the raw water and the effluent, and is adjusted in a direction to increase the C/N ratio of the mixed solution in the anaerobic tank 400.

The control method by the controller may be performed in the same steps as in the flowchart shown in FIG. 4 or FIG. 5 .

4 is a flowchart illustrating a control method according to the C/N ratio of the anaerobic tank 400 and the quality of the raw water. In this case, first, the water quality in the anaerobic tank 400 is measured, and when the C/N ratio is equal to or greater than the set value, the first line 10 and the second line 20 are closed and operated.

The set value of the C/N ratio may be set in the range of 2.0 to 14.0, preferably in the range of 2.5 to 10.0, more preferably in the range of 3.0 to 7.0. In particular, it is preferable that the C/N ratio is set to at least 3 or more for a smooth denitrification action in the anoxic tank 400 .

On the other hand, if the C/N ratio in the anaerobic tank 400 is less than the set value, the water quality of the raw water is measured, and when it is determined that the water quality is good, only the first line 10 is opened to increase the C/N ratio in the anaerobic tank 400 to increase, the opening rate of the first line 10 may be adjusted in response to the C/N ratio of the anaerobic tank 400 . At the same time, since the second line 20 is closed and operated, it is possible to induce an efficient denitrification reaction in the anoxic tank 400 while preventing additional water pollution due to excessive injection of an external carbon source.

In this way, when only the first line 10 is opened and the second line 20 is closed and operated, when the C/N ratio of the anaerobic tank 400 measured in real time is greater than or equal to the set value, the operation is performed in the same way and the anaerobic tank ( When the C/N ratio of 400 ) falls below the set value, the second line 20 may also be opened to increase the C/N ratio in the anaerobic tank 400 .

At this time, the measured water quality of raw water may include organic matter concentration, for example, BOD, and when the organic matter concentration is equal to or greater than a set value, it may be determined that the raw water quality is good.

In addition, while the C/N ratio in the anoxic tank 400 is less than the set value, it is difficult to increase the C/N ratio of the anoxic tank 400 because the concentration of organic matter in the raw water is low, or the nitrogen concentration in the effluent is high because the water quality of the effluent is poor. In such a case, the second line 20 is also opened and operated in the state in which the first line 10 is opened, but the amount of organic matter in the raw water is calculated so that the C/N ratio in the anoxic tank 400 is greater than or equal to the set value. The open rate of the first line 10 and the second line 20 may be adjusted.

In this case, the standards of water quality and organic matter concentration of raw water may be preset.

5 is a flowchart illustrating a control method according to the C/N ratio of the anoxic tank 400 and the water quality of the effluent. Also in this case, first, the water quality in the anaerobic tank 400 is measured, and when the C/N ratio is equal to or greater than the set value, the first line 10 and the second line 20 are closed and operated. The set value of the C/N ratio may be set in the same manner as described above.

In addition, when the C/N ratio in the anoxic tank 400 is less than the set value, the water quality of the effluent is measured, and when the water quality is good, both the first line 10 and the second line 20 are closed and operated. At this time, the measured water quality of the effluent may be a nitrogen concentration, and when the nitrogen concentration is less than a set value, it may be determined that the water quality is good.

On the other hand, if the C/N ratio in the anoxic tank 400 is less than the set value and it is determined that the water quality of the effluent is poor, only the first line 10 is opened to increase the C/N ratio in the anoxic tank 400 to promote the denitrification reaction. and the opening rate of the first line 10 may be adjusted according to the C/N ratio of the anoxic tank 400 . At this time, the first line 10 is opened and operated while the second line 20 is closed and operated, thereby preventing additional water pollution due to excessive injection of external carbon sources and inducing an efficient denitrification reaction in the anoxic tank 400 . have.

In this way, when only the first line 10 is opened and the second line 20 is closed and operated, when the C/N ratio of the anaerobic tank 400 measured in real time is greater than or equal to the set value, the operation is performed in the same way and the anaerobic tank ( When the C/N ratio of 400 ) falls below the set value, the second line 20 may also be opened to increase the C/N ratio in the anaerobic tank 400 .

In this case, the standards of the water quality and organic matter concentration of the effluent may be preset.

As the opening and closing rates of the first line 10 and the second line 20 are controlled in the multi-step manner as described above, the C/N ratio of the mixed solution in the anoxic tank 400 is increased to denitrify in the anaerobic tank 400 . It is possible to increase the reaction efficiency and at the same time reduce the total phosphorus and total nitrogen concentration in the finally discharged effluent, as well as reduce the denitrification efficiency due to the lack of external carbon sources or prevent additional water pollution due to excessive external carbon sources.

On the other hand, the treated water treated in the anoxic tank 400 flows into the membrane separation tank 500, is filtered by the immersion membrane unit disposed in the membrane separation tank 500, and flows out to the effluent, and the membrane separation tank 500 ), which is treated water, can be discharged or reused as reused water.

The separation membrane unit is installed so as to be immersed in the mixed solution in the membrane separation tank 500, and includes a plurality of separation membrane elements, and solid substances of a predetermined size or more contained in the mixed solution by the negative pressure generated inside the separation membrane elements are filtered. produced treated water. The separation membrane element may be a hollow fiber membrane filter, or may be a hollow fiber membrane filter unit in which at least two or more hollow fiber membrane filters are spaced apart from each other and arranged in parallel.

The solid material filtered by the separation membrane unit adheres to the surface of the separation membrane element and causes clogging of the separation membrane pores, thereby reducing the permeate flow rate by the separation membrane element, and increasing the internal and external pressure difference of the separation membrane element Therefore, there is a problem in that the final effluent production efficiency is reduced, the operating cost is increased, and the separation membrane element is easily damaged.

Accordingly, an air diffuser is provided at the lower end of the separation membrane unit to remove solid substances adhering to the surface of the separation membrane element by water flow due to the rise of air generated by driving the air diffuser, and the air diffuser generates negative pressure inside the separation membrane element. It may be driven at the same time or may be operated separately from the operation of the separation membrane element. In this case, the removal efficiency of the solid material adhering to the surface of the separation membrane element may be increased by driving the diffuser in a pulse manner.

As shown in FIG. 6, the diffuser includes a first diffuser pipe 510 and a second diffuser pipe 520 that are spaced apart from each other and arranged in parallel; a third diffuser pipe (530) having one end communicating with one end of the first diffuser pipe (510) through an elbow (L) and the other end communicating with the second diffuser pipe (520); and a fourth diffuser pipe 540 disposed to be spaced apart from the third diffuser pipe 530 by a predetermined distance, and disposed so that one end communicates with the first diffuser pipe 510 and the other end communicates with the second diffuser pipe 520 ; includes

A plurality of holes (H) are formed on the upper surface of the diffuser to be spaced apart from each other by a predetermined distance, and air is introduced through the other end of the first diffuser 510 and one end of the second diffuser 520 to form a plurality of holes (H). Since air bubbles are formed and discharged through the air bubble, the solid material on the surface of the separation membrane element located at the top of the air diffuser can be removed by the air bubbles.

As such, the air supplied to the inside of the diffuser is supplied through the other end of the first diffuser 510 and one end of the second diffuser 520, so that the air in the diffuser flows smoothly and through the plurality of holes H. A certain amount of air is discharged to increase the removal rate of foreign substances on the surface of the separation membrane element.

As the aerator is operated for a long time, sludge flows in and accumulates inside the aerator, thereby obstructing the air flow inside the aerator over time. This may be reduced and clogging of the separator element may occur.

In order to prevent this, a sludge discharge pipe 550 communicating with one side of the second diffusion pipe 520 and a valve 560 for controlling the opening and closing of the sludge discharge pipe 550 are provided, and the pump driving the separation membrane element is stopped During the intermittent or non-intermittent opening of the valve 560, the sludge in the aerator is discharged to the outside by an airlift pump method. At this time, by using an automatic valve as the valve 560, it is possible to periodically and automatically clean the diffuser. The pump for generating a negative pressure inside the separation membrane element operates or stops depending on the water level of the membrane separation tank 500, and when continuously operated, clogging of the separation membrane element occurs more easily, so that the membrane separation tank 500 is at a high level. As in the case of continuous operation, when continuous operation is required, it is operated in a textile that repeats operation and stop for a predetermined time to prevent blockage.

A backwashing device 600 connected to the separation membrane unit may be provided to prevent clogging of the separation membrane element.

The backwashing device 600 is connected to a line branched from the effluent pipe flowing out from the membrane separation tank 500, mixes a part of the effluent with a cleaning chemical, and flows into the inside of the separation membrane element, thereby removing the solid material on the surface of the separation membrane element. removed chemically and physically. As the cleaning agent used for backwashing, a known cleaning agent such as sodium hypochlorite, citric acid, hydrochloric acid, etc. may be used.

The operation of the backwashing device 600 may be manually performed by an operator or may be performed automatically at a predetermined cycle, or when the differential pressure, which is the pressure difference between the pressure inside the membrane element and the outside pressure, exceeds a predetermined pressure, the differential pressure It can be controlled to be within this allowable pressure range and operated automatically.

On the other hand, the high-efficiency wastewater membrane separation treatment system of the present invention may include a first return line 30 for returning the mixed solution in the anoxic tank 400 to be described later to the anaerobic tank 100 . Since the release rate of phosphorus by microorganisms in the anaerobic tank 100 increases as the concentration of organic matter is sufficient and the nitrite or nitrate nitrogen concentration is low, the denitrification is performed by the first return line 30 . As the mixed solution in the anaerobic tank 400 flows into the anaerobic tank 100 , the phosphorus release efficiency by the biological process in the anaerobic tank 100 is further improved.

In addition, since phosphorus contained in the raw water flowing into the anaerobic tank 400 through the first line 10 is returned to the anaerobic tank 100 and removed by a biological treatment method, the treated water flowing into the membrane separation tank 500 An increase in the total phosphorus concentration in the body can be prevented.

The high-efficiency wastewater membrane separation treatment system of the present invention may include a second conveying line 40 for conveying the mixed solution in the membrane separation tank 500 to the full-bombed tank 200 . Since the mixed solution in the membrane separation tank 500 containing a high concentration of microorganisms and free oxygen by the second transfer line 40 is returned to the full aeration tank 200, the concentration of microorganisms in the full aeration tank 200 (MLSS) is maintained. There is an effect that the maintenance of aerobic conditions in the full aeration tank 200 is advantageous by the dissolved oxygen in the mixed solution, and accordingly, the oxygen transfer efficiency of the full bombardment tank 200 is improved, thereby increasing the nitrification and organic matter removal efficiency. .

As described above, the high-efficiency wastewater membrane separation treatment system of the present invention is arranged in the order of the anaerobic tank 100, full aeration tank 200, oxygen reduction tank 300, anoxic tank 400 and membrane separation tank 500, and phosphorus A means for improving removal efficiency and a means for supplying organic matter to the anoxic tank 400 are provided, and the total phosphorus, total nitrogen and dissolved organic matter concentration in the final effluent by providing a first return line 30 and a second return line 40 effectively lowers the

In addition, the anoxic tank 400 is disposed at the rear end of the full aeration tank 200, and a means for additionally supplying an organic material to the anoxic tank 400 is provided to solve problems such as a decrease in the denitration reaction efficiency due to a lack of dissolved organic materials.

In addition, since the pre-aeration tank 200 is located at the front end of the anoxic tank 400, the total amount of nitrified nitrogen components in the pre-aeration tank 200 is introduced into the anaerobic tank 400 and denitrified to increase the amount of nitrogen removed, and unlike the prior art, the anaerobic tank Since there is no need for internal transport to the 400, it is possible to reduce the power cost.

The present invention is not limited to the specific embodiments and descriptions described above, and without departing from the gist of the present invention claimed in the claims, anyone with ordinary skill in the art to which the invention pertains can implement various modifications and such modifications shall fall within the protection scope of the present invention.

10: first line 20: second line
30: first conveyance line 40: second conveyance line
100: anaerobic tank 200: full aeration tank
210: agitator 211: rotating rod
212: wing 213: connector
300: oxygen reduction tank 400: anoxic tank
410: external carbon source injection device 500: membrane separation tank
600: backwashing device

Claims (15)

an anaerobic tank in which at least a portion of raw water is dividedly introduced, and phosphorus elution reaction occurs in an anaerobic atmosphere;
a full aeration tank in which the treated water treated in the anaerobic tank is introduced, and excessive phosphorus intake and nitrification reaction occur in an aerobic atmosphere;
an oxygen reduction tank in which the treated water treated in the full bombardment tank is introduced to remove free oxygen;
an anoxic tank in which the treated water and raw water treated in the oxygen reduction tank are introduced, and a denitration reaction occurs in an anoxic atmosphere; and
a membrane separation tank including a separation membrane unit for filtering the treated water to which the treated water treated in the anaerobic tank is introduced;
including,
As a means for increasing the concentration of organic matter in the anoxic tank for a sufficient denitrification reaction of the anoxic tank,
a first line through which the raw water is introduced into the anaerobic tank;
a second line through which an external carbon source is introduced into the anoxic tank from an external carbon source injection device for injecting an external carbon source into the anaerobic tank; and
a control unit for controlling an open rate of the first line and the second line;
further comprising,
The control unit opens the first line and the second line according to the C/N ratio in the anaerobic tank measured in real time, and at least one of the water quality of the raw water and the water quality of the effluent finally discharged from the high-efficiency wastewater membrane separation treatment system. adjust the rate,
When the control unit adjusts the opening rate of the first line and the second line according to the C/N ratio of the anaerobic tank and the quality of the raw water,
When the C/N ratio of the anaerobic tank is greater than the set value, the first and second lines are closed and operated,
If the C/N ratio of the anaerobic tank is less than the set value and the organic matter concentration of the raw water is high, only the first line is opened and operated, and the C/N ratio of the anaerobic tank is less than the set value and the organic matter concentration of the raw water is low If it is defective, both the 1st and 2nd lines are opened and operated.
When the control unit adjusts the opening rate of the first line and the second line according to the C/N ratio of the anaerobic tank and the water quality of the effluent,
When the C/N ratio of the anaerobic tank is less than the set value and the nitrogen concentration of the effluent finally discharged from the membrane separation tank is low and the water quality is good, the first and second lines are closed and operated, and the C/N ratio of the anaerobic tank is A high-efficiency wastewater membrane separation treatment system, characterized in that only the first line is opened and operated when the water quality is poor due to the high nitrogen concentration of the effluent and less than the set value. According to claim 1,
A stirrer is installed in the full bombardment tank,
While the mixed solution in the full aeration tank is stirred by the stirrer, at the same time, external air is introduced through the stirrer and aerated,
The stirrer,
a rotating rod vertically disposed with respect to the bottom surface of the full-width basic tank;
a wing part connected to the rotating rod to cause a flow motion in the mixed solution;
It connects the rotating rod and the wing part, and includes a connecting pipe formed by opening a boundary part connected to the rotating rod and the wing part,
The rotating rod, the wing portion and the connecting tube are formed in the form of an empty tube and communicate with each other,
One end of the rotating rod communicates with the outside air and the other end is sealed,
The connecting pipe is provided in plurality and is connected in a radial direction with respect to the rotating rod,
The wing portion has both ends open, the cross section of the central portion has a shape having an area smaller than the cross section of both ends, and the central axis of the wing portion is perpendicular to the central axis of the connecting tube while forming a horizontal plane formed by rotation of the connecting tube. A high-efficiency wastewater membrane separation treatment system, characterized in that it is connected at an angle with respect to the inclination. delete delete delete delete delete delete delete According to claim 1,
A high-efficiency wastewater membrane separation treatment system comprising a; a first return line for returning the mixed solution in the anaerobic tank to the anaerobic tank. According to claim 1,
A high-efficiency wastewater membrane separation treatment system comprising a; a second conveying line for conveying the mixed solution in the membrane separation tank to the full aeration tank. According to claim 1,
The separation membrane unit is installed so as to be immersed in the mixed solution in the membrane separation tank, and includes a plurality of separation membrane elements, so that solid substances of a predetermined size or more contained in the mixed solution by the negative pressure generated inside the separation membrane element are filtered treated water A high-efficiency wastewater membrane separation treatment system that produces 13. The method of claim 12,
A high-efficiency wastewater membrane separation treatment system, characterized in that a backwash device connected to the separation membrane unit is provided. According to claim 1,
Further comprising an air diffuser provided at the lower end of the separation membrane unit,
The aeration device is
A first diffuser and a second diffuser arranged in parallel spaced apart from each other by a predetermined distance;
a third diffuser having one end communicating with one end of the first diffuser through an elbow and the other end communicating with the second diffuser;
and a fourth diffuser disposed to be spaced apart from the third diffuser by a predetermined distance, one end of which is disposed to communicate with the first diffuser, and the other end of which is arranged to communicate with the second diffuser,
A plurality of holes are formed on the upper surface of each of the diffusers to be spaced apart from each other by a predetermined interval,
The high-efficiency wastewater membrane separation treatment system, characterized in that air is introduced from both directions through the other end of the first diffuser and one end of the second diffuser so that the introduced air is circulated in each of the diffusers. 15. The method of claim 14,
The aeration device is
a sludge discharge pipe communicating with the other end of the second aeration pipe; and
A high-efficiency wastewater membrane separation treatment system comprising a; valve for controlling the opening and closing of the sludge discharge pipe.

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