KR100291830B1 - Wastewater treatment method and apparatus for removing hydrogen and phosphorus from intermittent aeration - Google Patents

Abstract

The present invention relates to a wastewater treatment method and apparatus capable of serving as a defoaming device and a deodorizing device, including a pump (2) installed in a reaction tank (1), an outlet pipe (3) extending from an outlet of the pump (2), Nitrogen and phosphorus removal by using a wastewater treatment system and treatment method comprising an ejector (5) connected to an outlet pipe, an air supply pipe (8) connected to an ejector, a defoaming nozzle (15) connected to an outlet pipe, and a defoaming water valve (16). It can increase efficiency, improve aeration and agitation efficiency, reduce hydraulic load of reaction tank and sedimentation basin, and deodorize odor generated in concentration tank and dehydrator chamber biologically from reaction tank to separate vesicle tank, vesicle pump, internal circulation. The facility and the deodorization facility are no longer needed, so the maintenance cost such as facility cost and power cost can be reduced.

Description

Waste Water Treatment Method and Equipment for Removing Nitrogen and Phosphorus by Intermittent Aeration

The present invention relates to a wastewater treatment apparatus, and more particularly, to a wastewater treatment method and apparatus capable of efficiently removing nitrogen and phosphorus in sewage at the same time.

Pollutants in sewage are roughly divided into organic and nutrients, nitrogen and phosphorus, expressed in biochemical oxygen demand (BOD). Up to now, the sewage treatment plant has been mainly treated with organic matter, and much of the nutrients nitrogen and phosphorus could not be removed, but were discharged to the water system such as rivers.

If the sewage is discharged with nitrogen and phosphorus, it causes eutrophication in rivers and other waters, and if it enters the ocean, it can cause red tide. Severe eutrophication leads to odors and water pollution, as well as limited use of drinking water and waterways. Therefore, in order to prevent eutrophication of the water system as above, it is necessary to sufficiently remove nutrient nitrogen compounds or phosphates in the sewage treatment plant.

Nitrogen and phosphorus removal processes used in sewage treatment plants have a structure in which an anaerobic reactor that does not supply oxygen and an aerobic reactor that supplies oxygen are arranged separately. According to the characteristics of each reactor, the aerobic reactor converts organic nitrogen or ammonia nitrogen to nitrate nitrogen, and in the anaerobic reactor, nitrogen denitrification is reduced to nitrogen gas to induce denitrification and release of phosphorus from activated sludge.

The phosphorus component thus released is overingested by the microorganisms in the aerobic reactor, and the microorganisms ingesting the phosphorus are removed through the excess activated sludge to obtain the treated water from which nitrogen and phosphorus are finally removed.

In the conventional nitrogen and phosphorus removal method, a number of anaerobic tanks, anoxic tanks, and aerobic tanks are separately separated and fixedly installed at a predetermined capacity, so that they lack the capacity to flexibly cope with changes in inflow water quality and inflow water. In addition, in order to inject the methanol into the electron donor for denitrification or to use organic matter in the sewage, the water of the nitrification tank must be internally circulated to the denitrification tank of the previous stage. In case of injecting methanol, the chemical cost is large, and the internal circulation flow rate for using organic matter in the sewage is about 4 times greater than the treated flow rate. For example, in the case of a sewage treatment plant with a treatment capacity of 10,000m ³ / day, since the internal circulation flow rate is 40,000m ³ / day, a huge pumping facility is required, causing a lot of pump facility costs, power costs, and maintenance costs.

In order to solve this problem, an intermittent aeration method may be used to intermittently supply air to repeat anaerobic and aerobic conditions in one or more reactors. The intermittent aeration method repeats the aerobic state of supplying free oxygen and the anaerobic condition of not supplying free oxygen in the same reactor at a time interval. In the same reactor, the aeration tank is blown to repeat the anaerobic / aerobic state. It is to repeat the process of stopping.

By applying the intermittent aeration method described above, the number of reaction tanks can be reduced compared to the conventional treatment process, thereby reducing the mechanical construction cost, power cost, and facility operation cost.In particular, unlike the conventional method in which the capacity of the reaction tanks such as anaerobic tank and aerobic tank is fixed By adjusting the intermittent aeration time, it is possible to obtain the same effect as changing the reactor capacity in the conventional method, there is an advantage that can be flexibly coped even if the conditions of the influent change.

Although the intermittent aeration method has many advantages as described above, no clear device and method have been developed so far, and using the existing devices, it is inevitable to separate and install the aeration device and the mixing device. In more detail, when using a combination of conventional devices, as shown in Figure 2, a stirring device 103 composed of a blower device 102 and an air diffuser 105 for supplying air to the aeration tank 101 is required. It was. The stirring device 103 is a mixing device to enable the suspended sludge to be suspended and flow smoothly without settling at the bottom of the aeration tank in the aeration stage to stop the operation of the blower. If the blower device 102 and the stirring device 103 are separately installed, it is uneconomical in terms of facility cost and power cost, and also difficult to maintain.

In particular, when the stirring device 103 is composed of an underwater rotating body 104 that generates water flow, the biofilm contact material for attaching and propagating microorganisms collides with the underwater rotating body 104 of the stirring device and is broken. It was impossible.

In addition, a large amount of foam is generated in the aeration process of injecting air in the aeration tank of the sewage and wastewater treatment plant. Such a large amount of foaming is mainly caused by surfactants such as soaps and detergents contained in raw water or microorganisms that generate foam such as rocardia, and bubbles are scattered around the treatment plant under severe foaming and windy weather conditions. To cause secondary pollution.

As a countermeasure against such foaming, a nozzle is installed on the surface of the reactor to calm bubbles generated excessively in the reactor, and water is strongly sprayed through the nozzle. However, since the defoaming device, which is a foam dissolving device used in the past, uses treated sewage as parcel water, installation of the defoaming water tank and the defoaming water pump is inevitable in the next step of the final settling, and thus, the structure, mechanical work cost, power cost, and maintenance cost are additionally burdened. 3 shows that the conventional sewage and wastewater treatment system is not only inefficient but also deodorizing.

In addition, the conventional defoaming device is to flow back a large amount of treated sewage back to the reaction tank for use as parcel water, so that the load is increased by the flow rate corresponding to the parcel water, the surface area load rate of the sedimentation basin is increased to decrease the sedimentation efficiency There was a problem.

Accordingly, the present invention has been made to solve the above-mentioned problems, it is possible to reduce the facility cost and maintenance costs, and sewage treatment method that can efficiently apply the intermittent aeration method, a method for removing nitrogen and phosphorus in the sewage and The object is to provide a device.

The present invention for realizing the above object is a pump having an outlet pipe for aeration and stirring in the reaction tank; A mixed water pipe branched at the outlet pipe and installed at the bottom of the reactor; An ejector connector branched from the pump outlet and connected to one or more ejectors; And including the air supply pipe connected to each ejector is a wastewater treatment apparatus, characterized in that the aeration and stirring can be repeated alternately.

In another aspect, the present invention is a sewage water treatment device characterized in that the defoaming water pipe having a defoaming nozzle is branched from the ejector connecting pipe.

Looking at the operation of the sewage treatment apparatus of the present invention having such a structure as follows. In the aeration stage in which the reactor is operated in aerobic state, water is ejected from the ejector, and air is sucked into the ejector through the air supply pipe, mixed with water, and oxygen is supplied to the water stream. The generation of bubbles in the surface of the reactor by aeration is suppressed by the vesicle water. In addition, by the mixed water pipe, water flow is injected from the bottom of the reaction tank to stir the reaction liquid. Meanwhile, in the aeration phase, the air supply is stopped and stirring is continued to prevent deposition of suspended microorganisms. The stirring is performed while the discharged water from the pump is injected into the reactor through the mixed water pipe.

And the wastewater treatment method according to the present invention is provided with a pump having an outlet pipe for agitating the water in the reaction tank, a mixed water pipe installed in the bottom portion of the reaction tank branched from the outlet pipe, branched from the outlet pipe is provided with a water supply valve In the wastewater treatment system comprising an ejector connector connected to one or more ejectors, an air supply pipe connected to each ejector, and an air supply pipe connected to each air supply pipe, and an air supply valve is installed, wherein the water supply valve is normally opened to maintain the ejector and Water flows through the mixed water pipe to make agitation and intermittent opening and closing of the air supply valve is characterized in that the intermittent aeration is made, the air supply valve is always open by other means to eject the ejector Through the water supply valve It can also be opened and closed intermittently to control the water flow in the ejector to make abandonment intermittently.

1 is a conceptual perspective view of a sewage and wastewater treatment apparatus according to the present invention,

2 is a schematic diagram of a conventional intermittent aeration device;

3 is a system diagram of wastewater and wastewater treatment including a conventional defoaming apparatus.

-Explanation of symbols for the main parts of the drawings-

1: Reactor 2: Pump

3: outflow pipe 4: mixed water pipe

4a: mixed water flow control valve 5: ejector

6: ejector connector 6a: ejector connector

6b: ejector control valve 7: water flow supply valve

8: air supply pipe 8a: air control valve

9: nozzle 10: mixed water branch pipe

11: air supply main 11a; Air supply valve

13 water flow control valve 14 water flow control pipe

15: small nozzle 16: small water pipe

17: defoaming water control valve 18: biofilm contact material

19: pump room

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

1 is a perspective view of a reaction tank embodying an embodiment of a wastewater treatment apparatus for removing nitrogen and phosphorus by intermittent aeration according to the present invention, the wastewater treatment apparatus of the present invention is a pump ( 2), the outlet pipe 3 is extended from the outlet of the pump (2), the outlet pipe (3) is an ejector (5) which can inject water or inject a mixture of water and air Is branched into the ejector connecting pipe 6 and the mixing water flow pipe 4 connected to each other. The ejector 5 is installed in the ejector connecting pipe 6a, which is branched from the ejector connecting pipe 6, and has an ejector control valve 6b. Each ejector 5 has air The supply pipe 8 is connected so that air can be supplied to the reactor through the ejector 5. The ejector connecting pipe 6 branched from the outlet pipe 3 is provided with a water flow supply valve 7 to supply or stop the water flow to the ejector. The mixed water pipe 4 is provided with a mixed water flow control valve 4a and is connected to the mixed water flow pipe 10 having a plurality of injection holes 9 so as to spray water from the bottom of the reactor.

The air supply pipe 8 is connected to the air supply pipe 11 having a large diameter, and the air supply pipe 8 has a structure in which an air control valve 8a is installed. The air supply main pipe 11 is provided with an air supply valve 11a to supply or stop air to the reaction tank through the ejector 5.

On the other hand, the outlet pipe 3 is connected to the water flow control pipe 14 is provided with a water flow control valve 13 to adjust the flow rate ejected from the ejector 5, this water flow control pipe 14 A defoaming water pipe (16) having a defoaming nozzle (15) is connected, and the defoaming water pipe (16) is connected to a defoaming water control valve (17) that can control the injection of the defoaming water. The defoaming water pipe 16 may be directly connected to the outflow pipe 3.

In addition, in the present invention, the air supply main pipe 11 is connected to an exhaust port through which the odor-containing air generated in the concentration tank, the sludge dehydrator, the sludge fermentation tank, and the like is exhausted, so that the odor-containing air is supplied through the air supply pipe 8 and the ejector 5. The substance which flows into the reaction tank 1 and becomes a odor causing substance is deodorized by being oxidized or decomposed by the metabolic action of aerobic microorganisms.

Looking at the operation of the sewage and wastewater treatment apparatus equipped with a deodorizing function and defoaming function and intermittent aeration function of the present invention configured as described above are as follows.

First, in the aeration stage in which the reactor 1 is operated in an aerobic state to oxidize ammonia nitrogen contained in the sewage with nitrogen oxides, decompose organic matter, and ingest excessive phosphorus, the pump 2 is operated and the air supply pipe 8 is operated. The water supply valve 7 is opened while the air supply valve 11a connected to the air control valve 8a and the air supply main body 11 are open. As the water supply valve 7 opens, when water is ejected from the pump 2 through the ejector 5 at a high speed, the air supply main body 11 is formed by the negative pressure pressure energy formed around the ejector 5 nozzle. In order to sequentially pass through the air control valve 8a and the air supply pipe 8, air is sucked into the ejector 5, and water flows in which fine air bubbles are mixed are ejected from the ejector 5 into the reactor 1. At this time, oxygen is dissolved in the water body inside the reaction tank 1 at the gas-liquid contact surface of the air bubble, thereby forming an aerobic state. In addition, through the injection port 9 of the mixed shoe branch pipe 10 installed near the bottom of the reaction tank, the water flow is ejected and stirred, and at the same time it is possible to prevent the sludge deposited on the bottom.

In this abandoned state, air bubbles mixed through the ejector 5 rise to the surface of the reaction tank 1 and a large amount of bubbles are generated. In the aeration state in which air is supplied, bubbles are generated in the reaction tank 1, but the water flow supply valve 7 is opened, and at the same time, the discharge water flow of the pump 2 automatically flows through the defoaming nozzles 15 to the water surface of the reaction tank 1; Since it is sprayed on, bubbles are suppressed. When the water flow supply valve 7 is opened to give up by the ejector, the defoaming water is injected and the defoaming water flow rate can be adjusted by the defoaming water control valve 17. When the vesicles are sprayed, the foaming is suppressed as well as the vesicles in which the fine water flow comes into contact with the air reaches the reaction tank 1 in a state in which the dissolved oxygen is almost saturated, thereby bringing a synergistic effect of the aeration efficiency. When the reaction tank 1 is in this aerobic state, nitrification and decomposition of organic matter and phosphorus absorption by microorganisms are actively performed.

In the case where the odor-containing air generated in the concentration tank is supplied to the reaction tank through the air supply pipe and deodorized, the intake of the odor-containing air in the reaction tank is stopped when the water supply valve is closed. However, the sewage treatment plant is composed of a plurality of reaction tanks, and since the aeration and aeration are carried out alternately, the deodorizing function is also continued since the odor-containing air is continuously introduced into another reaction tank operated by the valve to be opened and aerobic. Since the substance causing the odor may corrode the metal depending on the type, when the odor-containing air is sucked into the intake port of the blower and sent to the reactor, the material rotates at a high speed to corrode the rotor and the case of the blower being operated at a relatively high temperature. However, in the wastewater treatment apparatus according to the present invention, since there is no driving portion in the air passage path and is operated at a low temperature, corrosion problems do not occur.

In the intermittent aeration phase, the denitrification reaction and the non-aeration phase, ie, anaerobic phase, which release phosphorus, stop the air supply. Even if the air supply is stopped, the stirring state must be maintained so that the suspension microorganisms are not deposited. Stirring is performed by the water flow ejected from the ejection port 9 of the ejector 5 or the mixed flow branch pipe 10. By closing the air supply valve 11a installed in the air supply main body 11 while the pump 2 continues to operate, water flow may be continuously injected from the ejector 5 to block the air supply, and the air supply valve 11a may In the open state, the water supply valve 7 may be closed to stop the flow of water from the ejector 5, thereby preventing air from entering. As the water flow continues to be injected from the ejector 5 and the air supply is stopped by closing the air supply valve 11a, the pressure energy used for the air intake is not converted into the kinetic energy required for the agitation. The stirring force of the reaction tank 1 becomes weak. Therefore, when the air supply valve 11a is opened and the water supply valve 7 is closed, the water flow is stopped from the ejector 5, but the water flow injected from the ejector 5 is further injected into the lower injection hole 9. It is advantageous to maintain the mixed strength. As described above, the inside of the reaction tank 1 is maintained by the jet water flow from the ejector 5 or the injection port 9, and the air supply is stopped. Therefore, oxygen is depleted by the respiration of the microorganisms and is converted into the anaerobic state. In this way, even in the anaerobic stage, the continuous stirring power is required so that the microorganisms or the biofilm contact material 18 inside the reaction tank 1 are not deposited. Such stirring is performed by the water flow ejected from the ejector 5 or the injection hole 9. do.

In the anaerobic stage, free oxygen in the reaction tank (1) not only lowers the release of phosphorus from the microorganism but also favors free oxygen dissolved in water rather than oxygen bound with nitrogen oxides in respiration of microorganisms that contribute to denitrification. This prevents denitrification. Therefore, in the anaerobic stage, if the spraying of the parcel water in which a large amount of oxygen is dissolved continues, the nitrogen and phosphorus removal efficiency is lowered. In addition, in the anaerobic step, since no air is injected into the reaction tank 1, it is advantageous to close the defoaming water valve 16 so that the amount of bubbles generated in the reaction tank 1 is small, and thus, the defoaming water is not injected from the defoaming nozzle 15. In this embodiment, when the water supply valve 7 is closed in order to switch to the non-aeration state, the water supply is automatically stopped in the defoaming water pipe 16, and the injection of the defoaming water is also stopped.

Various valves, such as the water supply valve 7 and the air supply valve 11a, are configured as automatic valves such as electric valves or pneumatic valves, and are configured to be opened and closed in conjunction with a timer, a redox potential controller, or a dissolved oxygen controller. It is desirable to enable this.

In addition to forming a negative pressure for sucking air, the water stream ejected from the ejector 5 floats the activated sludge in the reaction tank 1 together with the injection port 9 installed in the mixed water reservoir tube 10, or the fluidized biofilm A stirring function for flowing the contact material 18 is performed. However, depending on the operating situation, if the jet flow intensity from the ejector 5 and the jet port 9 is too large, a strong shear force is formed inside the reaction tank 1, so that the biofilm on the surface of the biofilm contact material 18 detaches. ) Or sludge-proliferated activated sludge is dispersed, which lowers the treatment efficiency. Thus, in the embodiment of the present invention, by discharging the water flow by discharging the water flow in the jet port 9 of the mixed water pipe 10 connected to the mixed water pipe 4, it is prevented that the ejection intensity of the ejector 5 is too large. When the flow rate ejected from the ejector 5 and the injection port 9 is excessively open, the water flow control valve 13 is partially opened so that a part of the flow rate discharged from the pump 2 is near the water surface of the reaction tank 1. The flow rate which is guided and ejected from the ejector 5 and the injection port 9 can be adjusted.

That is, in order to reduce the flow rate ejected from the ejector 5 and the injection port 9, the flow rate control valve 13 can be opened little by little to bypass the water flow rate of the reaction tank 1 to adjust the ejection flow rate. (1) It is possible to control the mixing strength of the inside, and if the biofilm is excessively attached to the biofilm contact material 18 is required to artificially remove (Sloughing), the water flow control valve 13 is completely sealed to the ejector (5) And the flow rate of the water flow from the injection port 9 can be increased.

In addition, the pump (2) can also be configured underwater or above ground.

The air control valve 8a is a valve provided in each air supply pipe 8 to adjust the air intake amount supplied into the reaction tank 1. By adjusting the air control valve (8a) it is possible to adjust the amount of air sucked into each ejector (5) to be able to adjust the amount of air in the reaction tank (1). In particular, when the reactor 1 is in the form of a plug flow reactor, since oxygen demand varies depending on the position of the reactor 1, the dissolved oxygen concentration is maintained evenly throughout the reactor 1 by adjusting the aeration amount of each ejector 5. It becomes possible.

In addition, in the case of using the submersible pump, it is advantageous to install the pump 2 in the reaction chamber 1 and install it in a separate pump chamber made of a separation wall. Complexes may be mixed into the reactor 1, and the compacts may close the small nozzles 15 having small diameters. Above all, the problem may be that when the small fluidized bed biofilm contact member 18 is filled in the reaction tank 1, it may flow into the inlet of the pump 2, and in order to repair the water pump in particular, The fluidized bed biofilm contact material 18 becomes an obstacle in the re-installation work after lifting the pump 2. That is, since the agitation is stopped when the pump 2 is lifted for repairing, the biofilm contact materials 18 are deposited on the bottom of the reaction tank 1, and the biofilm contact materials 18 stacked on the bottom when re-installation are lifted. There is a problem in that the pump 2 becomes an obstacle preventing it from being seated in place. As a countermeasure against this problem, it is preferable to configure the pump chamber 19 by installing a porous partition wall composed of a net or screen around the submersible pump 2.

As described above, when the sewage treatment apparatus according to the present invention is used, water is injected from the bottom of the reaction tank through the mixing water pipe and the mixing water pipe in addition to the ejector, so that the sludge is prevented from being deposited, and the aeration and agitation force are necessary. It can be controlled to prevent excessive oxygen supply, so that it can be quickly converted to anoxic conditions, thereby improving the denitrification efficiency. And when abandoned, the vesicles are sprayed to suppress the generation of bubbles in the reaction tank and to prevent the excessive shear force acting on the microorganisms attached to the biofilm contact material it is easy to adopt the biofilm method to fill the contact material. In addition, it is possible to omit or reduce the capacity of the separate blower and the corresponding blower chamber building, and it is unnecessary to install a defoaming tank, a defoaming water pump and a deodorizing facility that suppresses the foaming of the aeration tank. In addition, energy and maintenance costs can be reduced, and in particular, the removal efficiency of nitrogen and phosphorus, which are the causes of eutrophication, can be effectively increased.

Claims (12)

A wastewater treatment apparatus for introducing wastewater and treating the same in a reaction tank to separate and discharge treated water and sludge, the wastewater treatment apparatus comprising: a pump having an outlet pipe for stirring water flow in the reaction tank; A mixed water pipe branched at the outlet pipe and installed at the bottom of the reactor; One or more ejectors branched from the flow pipe is connected to the pipe; An air supply pipe connected to each of the ejectors; And a waste water treatment apparatus configured to allow aeration and agitation to be performed inside the reactor by the operation of the flow rate control means and the driving of the pump. According to claim 1, wherein the air supply pipe is connected to the air supply main and the air supply main is connected to the odor-containing air exhausted from the odor source, such as the concentration tank or dehydrator chamber is introduced, stirring and intermittent aeration Sewage water treatment device, characterized in that the odor can be removed at the same time. The wastewater treatment apparatus according to claim 1 or 2, wherein an ejector connection pipe is installed in the ejector connection pipe to connect the ejector to an intermediate portion of the reaction tank. The wastewater treatment apparatus according to claim 1 or 2, wherein a water flow control pipe is branched to the ejector connection pipe, and a water flow control valve is provided as a flow rate control means in the water flow control pipe. The sewage water treatment apparatus according to claim 1 or 2, wherein a defoaming water pipe having a defoaming nozzle is branched and connected to the ejector connecting pipe, and the defoaming water pipe is provided as a flow control means. The sewage treatment apparatus according to claim 1 or 2, wherein a water flow supply valve is installed as a flow control means of the ejector connecting pipe. The sewage water treatment apparatus according to claim 1, wherein a mixed water flow control valve is provided as a flow rate control means of the mixed water pipe. The wastewater treatment apparatus according to claim 1 or 7, wherein a mixed water flow branch pipe having a jetting port is connected to the mixed water flow pipe. 3. The wastewater treatment apparatus according to claim 2, wherein an air supply valve is installed as a flow control means of the air supply main body. The wastewater treatment apparatus according to claim 3, wherein an ejector control valve is provided as a flow control means of the ejector connection pipe. A pump having an outlet pipe for agitating the water stream in the reactor, a mixed water pipe branched from the outlet pipe and installed at the bottom of the reactor, a water supply valve branched from the outlet pipe, and an ejector connection pipe connected to one or more ejectors; A method for treating sewage by driving a sewage treatment apparatus including an air supply main pipe connected to each ejector and having an air supply valve installed therein, wherein the water supply valve is always opened to eject water flow through the ejector and the mixed water pipe. And agitation is made and the air supply valve is intermittently opened and closed to allow intermittent aeration. A pump having an outlet pipe for agitating the water stream in the reactor, a mixed water pipe branched from the outlet pipe and installed at the bottom of the reactor, a water supply valve branched from the outlet pipe, and an ejector connection pipe connected to one or more ejectors; In the wastewater treatment system comprising an air supply pipe connected to each ejector and an air supply pipe connected to each air supply pipe and an air supply valve is installed, the air supply valve is normally opened so that air can be supplied to the reactor through the ejector. And intermittently opening and closing the water supply valve to adjust water flow in the ejector so as to give up intermittently.