KR101371220B1 - Method for simultaneous removal of nitrogend and organic in the waste water using membrane bioreactor - Google Patents

Abstract

The present invention improves the quality of the final effluent and energy consumption by simultaneously removing the organics and nitrogen of the wastewater biologically using one reactor and removing particulate and dissolved contaminants that are not removed by biological reaction using the membrane. Disclosed is a wastewater treatment method that can save money and reduce the sludge treatment burden. The disclosed invention includes the step of removing residual organics and nitrogen, and particulate and dissolved contaminants in the wastewater using a fluidized bed Anamox reactor. The step may include removing nitrogen in the effluent by using an Anamox reaction using a microorganism retained in the fluidized-bed separator Anamox reaction tank; Removing organic matter through nitrous acid and denitrification by using heterotrophic denitrification bacteria remaining in the fluidized-bed separator Anammox reactor; And removing particulates and dissolved contaminants in the effluent that are not removed by biological reaction using a membrane immersed in the fluidized bed separator Anammox reactor.

Description

METHOD FOR SIMULTANEOUS REMOVAL OF NITROGEND AND ORGANIC IN THE WASTE WATER USING MEMBRANE BIOREACTOR}

The present invention relates to a wastewater treatment method, and more specifically, by using a membrane to economically remove organic matter and nitrogen contained in various wastewaters such as domestic wastewater or industrial wastewater, and to remove particulate and dissolved contaminants which are not removed by biological reaction. The present invention relates to a method of simultaneously removing nitrogen and organics from wastewater using a membrane reactor that can improve the quality of the final effluent, reduce energy consumption, and reduce sludge generation.

Water pollution caused by living wastewater and various industrial wastewater in modern society is not only destroying the ecosystem but also causing serious depletion of industrial and agricultural water and drinking water.

The causes of such water pollution include organic substances and inorganic substances such as nitrogen and phosphorus. Nitrogen is one of the nutrients, which causes side effects and red tide to promote the generation of harmful suspended organisms and cause an increase in chemical oxygen demand.

As a method of treating wastewater containing such various pollutants, the metabolic action of aquatic microorganisms is used.

In general, the wastewater treatment method is a form in which the organic matter in the wastewater is decomposed and treated using an aerobic microorganism in a reaction tank. However, such a general wastewater treatment method has a disadvantage in that a large amount of power consumption is required for the operation of an diffuser or a blower for supplying air into the reaction tank. In Korea, it is known that about 40% of the total power consumption of sewage treatment plants is used for blower operation.

In addition, nitrogen in the wastewater is generally removed by nitrification / denitrification (dependent nutrient denitrification) process (eg, MLE, A2O process, etc.).

Nitrification

1) nitrite ^{_{Chemistry: 55NH 4 + + 76O 2 +}} 109HC0 3 - → C 5 H 7 O 2 N + 54NO 2 - + 57H 2 O + 104H 2 CO 3

2) _{^{nitrification: 400NO 2 - + NH 4 +}} + 4H 2 CO 3 + HCO 3 - + 195O 2 → C 5 H 7 O 2 N + 3H 2 O + 400NO 3 -

3) general ^{_{formula: NH 4 + + 1.83O 2 +}} 1.98HCO 3 - → 0.021C 5 H 7 O 2 N + 0.98NO 3 - + 1.041H 2 O + 1.88H 2 CO 3

Denitrification

^{_{NO 3 - + 1.08CH 3 OH +}} 0.24H 2 CO 3 → 0.056C 5 H 7 O 2 N + 0.47N 2 + 1.68H 2 O + HCO 3 -

However, when nitrogen is removed by the general nitrification / denitrification process, a large amount of air must be supplied to nitrify ammonia to nitrate, and organic matter is needed for denitrification. There is a problem that the cost increases.

The nitrogen removal process proposed to solve this problem is the Anamox process. The reaction scheme of this process is as follows.

Anammox

_{^{NH 4 + + 1.32NO 2 - +}} 0.066HCO 3 - + 0.13H + → 1.02N 2 + 0.26NO 3 - + 0.066CH 2 O 0 .5 N 0 .15 + 2.03H 2 O

The Anamox process removes nitrogen by reacting ammonia and nitrite to generate nitrogen gas, which reduces the power consumption required for ammonia oxidation, does not require the addition of organic matter, and reduces sludge generation compared to general nitrification / denitrification processes. It is very economical. However, the disadvantage of the Anamox process is that the retention of the microorganisms in the reactor is very important because of the slow growth rate of the anoxix microorganisms, especially when the microorganisms are lost in the reactor. The Anamox process has yet been applied to high concentrations of nitrogen wastewater, and at low concentrations, few applications have been linked to the slow growth rate of these microorganisms.

delete

The present invention has been devised in view of the above, in the method of treating wastewater containing ammonia nitrogen and relatively low organic matter, by supplying a low concentration of dissolved oxygen to convert a portion of ammonia nitrogen to nitrite, The resulting nitrite is combined with residual ammonia nitrogen and removed with nitrogen gas (anamox process), in which some nitrites and nitrates generated in the anamox process are combined with organic matter contained in the wastewater (dependent nutrient denitrification). By removing the organics and nitrogen at the same time, while using the membrane to prevent the loss of the very slow growth of Anamox microorganisms to improve the process stability and to reduce the processing cost and sludge generation compared to the conventional nitrogen removal process Simultaneous Removal of Nitrogen and Organics in Wastewater Using Reactor The purpose is to provide a law.

Another object of the present invention is not only to improve the water quality of the treated water by removing the organic matter and nitrogen in one reactor but also remove particulate and some dissolved contaminants which are not removed by biological reaction. This simple and reduced land use area provides a method for the simultaneous removal of nitrogen and organics from wastewater using membrane reactors.

Simultaneous removal method of nitrogen and organics in the wastewater using the membrane reaction tank according to the present invention for achieving the above object comprises the step of simultaneously removing residual organic matter, particulate contaminants and nitrogen in the wastewater by using a fluidized-bed separator Anax The step may include the step of partially oxidizing the ammonia nitrogen contained in the wastewater to nitrite; Removing nitrite and ammonia nitrogen with nitrogen gas using an anoxix microorganism retained in the fluidized-bed separator anoxix reactor; Removing nitrite and nitrate remaining in the fluidized-bed separator anoxix reactor with nitrogen gas by heterotrophic denitrification using an organic material; And removing particulates and dissolved contaminants in the effluent that are not removed by biological reaction using a membrane immersed in the fluidized bed separator Anammox reactor.

According to a preferred embodiment of the present invention, a method of simultaneously removing nitrogen and organics in wastewater using a membrane reaction tank, circulating the effluent stored in the fluidized-bed separator anoxix reaction tank using a circulation unit to attach the anomax microorganisms In addition to flowing the particles of the flow, while preventing the loss of microorganisms can be processed in a short time due to the high mass transfer rate.

In addition, the method for simultaneously removing nitrogen and organics in the wastewater using the membrane reaction tank of the present invention, by injecting air into the fluidized-bed separator Anamox reaction tank using an air supply unit, a low concentration of dissolved for nitrite production required for the anamox reaction Adjusting the oxygen atmosphere, the air supply unit can maintain and maintain the dissolved oxygen concentration of the fluidized-bed separator Anamox reaction tank to 0.1 to 0.3 mg / L.

In addition, the method of simultaneously removing nitrogen and organics in the wastewater using the membrane reaction tank of the present invention, by connecting the outflow pump to the membrane to discharge the effluent inside the fluidized-bed separation membrane Anamox reaction tank to the outside by the particulate and dissolved contaminants in the effluent Can be filtered by the membrane.

According to the present invention, the structure of the system can be simplified because nitrogen and organic contaminants in the wastewater can be removed at the same time in one fluidized-bed separator Anamox reactor, and since there is no particulate contaminant in the effluent, It is easy to apply and the amount of sludge generated is significantly reduced, which can reduce the sludge treatment burden.

In addition, in the method of simultaneously removing nitrogen and organics in the wastewater using the membrane reactor according to the present invention, a small amount of dissolved oxygen (that is, about 0.1 to 0.3 mg / L) is maintained to oxidize a part of ammonia to nitrite, followed by an anomax process. Since nitrogen is removed from the wastewater, the power consumption for supplying the air required to oxidize ammonia can be greatly reduced, no organic matter is added for nitrogen removal, and sludge generation is less than that of the existing process. Organics remaining in the influent wastewater are consumed and treated to reduce nitrite or nitrate, a by-product of the Anamox process, to nitrogen gas, thereby improving water quality.

1 is a view showing the main part of a wastewater treatment system for implementing a method for simultaneously removing nitrogen and organics in wastewater using a membrane reaction tank according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention may be variously modified and may have various forms, and exemplary embodiments will be described in detail. It is to be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but on the contrary, is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise.

Also, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the meaning of the context in the relevant art and, unless explicitly defined herein, are to be interpreted as ideal or overly formal Do not.

1 is a view schematically showing the main part of a system for implementing a method for simultaneously removing nitrogen and organics in wastewater using a membrane reactor according to an embodiment of the present invention. First, the structure of the system will be briefly described.

The wastewater treatment system for implementing the present invention is mainly composed of a fluidized-bed separator Anamox reactor. The fluidized-bed separator Anamox in FMBR removes residual organic matter contained in wastewater or effluent flowing out of the biological reactor of the previous stage, and removes nitrogen in the effluent by the Anamox process. By removing the particulate and dissolved contaminants in the effluent not removed by the membrane, it is possible to improve the water quality of the effluent, to reduce the power consumption and sludge generation due to the characteristics of the Anamox process.

The fluidized phase separation membrane Anamox reaction tank 50 as described above includes a reaction tank body 51 containing an anoxix microorganism, a flow particle 52 attached to and flows an anoxix microorganism inside the reaction tank body 51, and the reaction tank. Gas-flowing particle separator 53 provided on the upper portion of the main body 51, membrane 54 for immersing in the reactor body 51 to remove particulate and dissolved contaminants in the effluent not removed by the microorganism, the reaction tank A circulation unit 55 for circulating the effluent in the main body 51, an air supply unit 56 and a membrane 54 for supplying / controlling a low concentration of dissolved oxygen required for an anax process inside the reactor main body 51. And an outflow pump 57 for outflow of the outflow water in the reactor body 51 to the outside.

The fluid particles 52 are in contact with the support medium for the anoxix microorganism and the membrane 54 to control the clogging phenomenon of the membrane 54 by removing the particles accumulated on the surface thereof, the fluid particles 52 Granular activated carbon (GAC) may be preferably used.

The gas-flowing particle separator 53 is provided with a loss preventing device 53a for preventing the loss of the flowed particles 52 flowing in the reactor body 51. In addition, if necessary, the gas-flowing particle separator 53 includes a second gas provided with a second loss prevention device 53b for secondarily preventing the loss of the flowed particles 52 flowing in the reactor body 51. -The fluid particle separator 53-1 may be connected.

In addition, the gas-flowing particle separator 53 is connected to a gas discharge pipe 58 for discharging the gas generated in the reactor body 51 to the outside, and the water level of the reactor body 51 The water level sensor 59 for detecting is installed.

According to the water level detection signal in the reactor body 51 by the water level sensor 59, the controller 60 controls the driving of the wastewater transfer pump 45 to appropriately adjust the amount of wastewater flowing into the reactor body 51. Adjust.

The membrane 54 may be formed of a hollow fiber membrane or a flat membrane having a plurality of micropores, and the micropores filter and remove contaminants in the effluent as the effluent passes but does not pass other particulate contaminants. Therefore, the final discharged effluent is completely free of particulate matter and no microorganisms or pathogens are present, and the scope and applicability of the applied technology is high when subsequent treatment is required.

In addition, since the microorganisms involved in the Anax process in the effluent remain in the fluidized-bed separator Anamox reaction tank 50, it is possible to solve the problem due to the loss of microorganisms known as the most weak point of the Anax process. In addition, the sludge generation is very small compared to the existing heterotrophic denitrification process because the Anamox process is used, and other microorganisms also have a long residence time, so the sludge generation is minimized and the burden of the sludge treatment in the subsequent process can be reduced. have.

The circulation unit 55 is for circulating the effluent in the reactor body 51, and the gas-flow particle separator 53 (the second gas-as shown in the example) at the lower portion of the reactor body 51. When the flow particle separator is provided, the circulation line 55a connecting the second gas-flow particle separator 53-1), the circulation pump 55b and the flow meter 55c installed in the circulation line 55a are provided. Equipped. The wastewater transfer pump 45 is connected to the circulation line 55a to supply wastewater to the circulation unit 55.

The waste water transported by the wastewater transfer pump 45 is transferred along the circulation line 55a as the circulation pump 55b is driven, and then flows in from the lower portion of the reactor body 51 so that the reactor body 51 The flow of the fluid occurs in the fluid flows in the reaction chamber body 51 in the reaction chamber (51) up. Here, the flow particles 52 flow in a balance with the upward velocity of the fluid flowing around the particles, the loss of the fluid particles 52a, 53b installed in the gas-flow particle separator (53, 53-1) Instead, it remains in the reactor body 51.

The air supply unit 56 supplies air to the reactor body 51 in order to generate dissolved oxygen required to generate nitrite from partial ammonia oxidation, ie, ammonia, required in the reactor body 51 as a preliminary step of the anamok reaction. And an air supply 56a and a flow meter 56b for adjusting the amount of air supplied from the air supply 56a. Here, the air supply unit 56 may be connected to the circulation line 55a or directly to the reactor body 51. In addition, the air supply unit 56 may be installed in the form of a general diffuser or gas permeable membrane in the fluidized phase separation membrane Anamox reaction tank.

The anamox reaction removes nitrogen by reacting ammonia and nitrous acid to generate nitrogen gas. For this anamox reaction, partial nitrification is required to partially convert ammonia in wastewater to nitrous acid. This partial nitrification process should keep the dissolved oxygen concentration low and constant, and the results of the experiment showed that the dissolved oxygen concentration was 0.1 to 0.3 mg / L, preferably 0.2 mg / L or less.

Simultaneous removal of nitrogen and organics from the wastewater using the membrane reactor using the above system is as follows.

Wastewater is transferred to the fluidized-bed separator Anamox reaction tank by the wastewater transfer pump 45, and the wastewater stored in the reactor body 51 flows through the circulation unit 55, such as biological reaction and contaminant filtering as described below. The process is carried out.

Specifically, in the fluidized-bed separator Anamox reaction tank, nitrogen is partially nitrified with nitrite and then removed by the Anamox process, and organic matter in the influent is used for denitrification of nitrite and nitrate, or part is removed by oxidation, and is removed by biological reaction. Particulate and dissolved contaminants in untreated effluents are filtered off by the membrane.

Meanwhile, dissolved oxygen is injected into the reactor body 51 from the air supply unit 56 in order to create a low concentration of dissolved oxygen atmosphere required for the anamok process, and also to filter particulate contaminants by the membrane 54. The outflow pump 57 pumps out the wastewater in the reactor body 51 through the membrane.

In other words, the method for simultaneously removing nitrogen and organics from wastewater using the membrane reactor according to the present invention removes nitrogen and organics from the wastewater using a single fluidized-bed membrane anoxix reactor, and particulate and dissolved contamination in the effluent using the membrane. The removal of the material takes place almost simultaneously, purifying the wastewater.

Therefore, it is not necessary to provide a plurality of reaction tanks, and the amount of sludge generated is reduced, so that the facilities of the wastewater treatment system can be simplified, and the site area can be reduced. Can be.

In addition, since the removal of nitrogen in the wastewater using the Anamox process, it is possible to implement a very economical and practical wastewater treatment system, such as to significantly reduce the power consumption of the air supply unit required for nitrogen removal.

While the invention has been described with respect to specific embodiments thereof, it will be apparent to one skilled in the art that the invention may be embodied in other specific forms without departing from the essential characteristics thereof. Accordingly, the described embodiments are to be considered in all respects as illustrative and not restrictive, and therefore, all modifications apparent to those skilled in the art are included therein.

45; wastewater transfer pump 51; reactor body
52; fluid particles 53,53-1; gas-fluid particle separator
54; membrane 55; circulating unit
56; air supply unit 57; outflow pump
58; gas discharge pipe 59; water level sensor
60; control unit

Claims (4)

As a method of treating wastewater containing ammonia nitrogen and organic matter,
Removing organic matter and nitrogen from the wastewater using a single fluidized-bed separator Anamox reactor,
Wherein the step
Removing nitrogen in the effluent by an anamok process by using microorganisms remaining in the fluidized-bed separator Anammox reaction tank;
Removing organic matter through nitrous acid and denitrification by using heterotrophic denitrification bacteria remaining in the fluidized-bed separator Anammox reactor; And
And removing particulate and dissolved contaminants in the effluent not removed by biological reaction using a membrane immersed in the fluidized-bed separator Anamox reactor.
By using the air supply unit to inject air into the fluidized-bed separator Anamox reaction tank to adjust the dissolved oxygen concentration required for the Anamox process,
The air supply unit is a method for removing nitrogen and organics in the wastewater by using a membrane reaction tank, characterized in that to maintain the dissolved oxygen concentration of the fluidized-bed separator Anamox reaction tank to 0.1 to 0.3 mg / L. The method of claim 1,
Nitrogen and organics in the wastewater using the membrane reaction tank to circulate the effluent stored in the fluidized-bed separator Anamox reaction tank using a circulation unit to carry out contaminant treatment while flowing a plurality of fluidized particles attached to the anamox microorganisms Simultaneous removal method. delete The method of claim 1,
By connecting the outlet pump to the membrane to discharge the effluent inside the fluidized-bed separator Anamox reactor to the outside to allow particulate and dissolved contaminants in the effluent to be filtered by the membrane nitrogen and organics of the wastewater using the membrane reaction tank Simultaneous removal method.

Images