KR20090021987A - Wastewater disposal system using internal circulation and rotating disk type nitrification tank - Google Patents

Abstract

A system for processing waste water using internal circulation and a nitrification tank of a rotating disk type is provided to isolate biomembrane from a surface of the disk. A system for processing waste water using internal circulation and a nitrification tank of a rotating disk type comprises the followings: a contact tank(1) absorbing a toxic material and an organic compound with activated sludge; a first settling tank(2) separating supernatant liquid and the sludge; the nitrification tank of the rotating disk type(3) inducing removal of ammonia nitrogen from the supernatant liquid; a first anoxic tank(4) denitrifying nitrate nitrogen; an intermittent aeration reaction tank(5) performing a nitrification and a denitrifying function; a second anoxic tank(6) denitrifying the nitrate nitrogen additionally; and a reaeration tank(7) performing nitrification of the residual ammonia nitrogen.

Description

Wastewater treatment system using internal circulation and rotating disk-type nitrification reactor {WASTEWATER DISPOSAL SYSTEM USING INTERNAL CIRCULATION AND ROTATING DISK TYPE NITRIFICATION TANK}

In order to effectively remove organic matter, nitrogen and phosphorus contained in high concentration organic wastewater such as urban sewage, livestock waste, and industrial wastewater with low C / N ratio, the internal circulation and rotational disc type nitrification The present invention relates to a wastewater treatment system using a reactor.

In general, nutrients contained in wastewater are inorganic elements, but when they enter rivers, coastal seas, lakes (lakes and reservoirs), etc., algae grow and cause eutrophication.

In addition, when the nutrients contained in the wastewater enter the coastal seas, red tide occurs, and if the odors occur due to decay at the bottom of the water, it acts as a cause to promote water pollution. It must be removed before it is introduced.

Most sewage treatment and livestock wastewater treatment methods in Korea depend on activated sludge method, but the activated sludge method removes most suspended solids and organic matter, while treating nutrients such as nitrogen and phosphorus is 20 ~ 40. Only%.

The processes for treating nutrients such as nitrogen and phosphorus include physical and chemical treatment methods and biological treatment methods.

Firstly, physical treatment methods include ammonia degassing, ion exchange using selective adsorption, precipitation of phosphorus using slaked lime and flocculant, and precipitation of struvite formation that simultaneously precipitates nitrogen and phosphorus. It is used. However, such a method has the disadvantage that the treatment is made selectively, but temperature-sensitive and expensive, etc., and the operation cost is difficult because the specific environment required for the drug cost and operation, Effluents are unstable, making them unusable in the world.

On the other hand, in the case of nitrogen, in the case of nitrogen, nitrification (ie, ammonia to nitrate form) is carried out by nitrifying bacteria (ie, Nitrosomonas & Nitrobacter) in aerobic conditions in ammonia nitrogen and organic nitrogen in a dissolved state, and denitrification of nitrates. Oxidizing bacteria (ie, Pseudomonas, Paracoccus denitrifiers) are used as electron acceptors instead of oxygen under anoxic conditions, converted to nitrogen gas, and released into the atmosphere (denitrification) and removed. In the case of phosphorus, wastewater is alternately maintained under anaerobic and aerobic conditions, releasing phosphorus from phosphorus-removing microorganisms (ie. Acinetobacter) under anaerobic conditions, and in subsequent aerobic conditions, the microorganisms overdose phosphorus and then Phosphorus in the wastewater is removed in a fixed amount.

The degree of ingestion of phosphorus by the microorganisms in the aerobic condition depends on the amount and type of organic matter introduced into the anaerobic condition, especially in the case of maintaining a pure anaerobic state and in the case of a large amount of organic acid salts such as acetate in pure anaerobic condition The amount of phosphorus released is enhanced, and the intake of phosphorus in the subsequent exhaled state is improved, thereby increasing the throughput.

Therefore, the biological nitrogen and phosphorus removal process is appropriately arranged anaerobic-aerobic-anaerobic-aerobic reactors in accordance with the characteristics of each reactor, in the aerobic reactors to induce organic oxidation and nitrification reactions and microorganisms intake of phosphorus, anaerobic and anoxic reactor Induces the release of phosphorus and the denitrification that releases nitrate nitrogen into nitrogen gas to the atmosphere.

In the above-described general treatment process of biological nutrients, an aerobic reactor is disposed before the precipitation tank to improve the sludge settling property and suppress the release of phosphorus. Examples of such a method include the Bardenpho process disclosed in US Pat. No. 3,964,988 to Barnard et al., A single system A / O process, A2 / O process and the like. These processes operate in a steady-state state in which wastewater is passed through anaerobic and aerobic reactors by separating and arranging reactors according to the presence or absence of oxygen, and ensuring good water quality when treating wastewater in general. In case of treating sewage with low organic matter / nitrogen (C / N) ratio as in processes or Korea, there was a problem in that nitrogen and phosphorus removal efficiency was lowered due to lack of organic matter during denitrification or anaerobic phosphorus release.

The DEPHANOX process developed in Italy is a way to overcome the wastewater treatment problem with low C / N ratio. In this process, the anaerobic contacting tank and the separation tank are used for the microorganisms to adsorb organic matter and induce the release of phosphorus in the anaerobic contacting tank, the organic matter and microorganisms adsorbed in the separation tank are separated into the subsequent denitrification tank and the nitrogen is not adsorbed. The compound is nitrified in a separate reactor and sent to a subsequent denitrification tank for denitrification by the microorganisms that adsorb the organics. That is, the DEPHANOX process is a process in which denitrification and nitrification are carried out in separate sludges and reactors, and the phosphorus is excessively ingested by microorganisms in a subsequent aerobic reactor.

However, even with this advantage of DEPHANOX process, organic nitrogen and ammonia nitrogen flowing into the denitrification tank from the separation tank after the nitrification process are not sufficiently decomposed or nitrified and discharged, and denitrification is carried out only in a single denitrification tank following the nitrification reactor. Therefore, there was a problem that high nitrogen removal efficiency cannot be expected.

In order to solve the above problem, the present inventors have applied for a patent similar to the present invention and registered (registered patent 10-0640940; published date 2006.11.06) prior to the present invention. However, the registered patent has a problem in that the backwashing should be periodically performed when filling the floating and fixed bed and the medium in the process of filling the nitrification tank and the medium, and when using the fluid bed and the medium, the aeration in the reactor If it does not occur uniformly, there was a problem that the nitrification and the medium does not flow smoothly in the reaction tank to reduce the nitrification efficiency.

In order to solve the problems as described above, the present invention improves the denitrification efficiency by supplementing the registered Patent No. 10-0640940 (announced 2006.11.06) filed by the present inventors, does not require a separate backwashing process, flow The purpose of the present invention is to provide a wastewater treatment system using an internal circulation and a rotating disk-type nitrification tank, which can eliminate the possibility of blocking the flow of the wall and media, which may occur when the media and the media are used.

In order to achieve the above object, in the present invention, by adsorbing organic substances and toxic substances contained in the inflow wastewater using activated sludge, the nitrification bacteria of the subsequent nitrification tank can be subjected to nitrification without being affected by the toxic substances. Contact tanks operated in aerobic or anaerobic conditions,

After separating the activated sludge adsorbed with organic matter and the supernatant containing a large amount of ammonia from the wastewater passed through the contact tank, the supernatant is transferred to the nitrification tank and the activated sludge is transferred to the first anoxic tank, respectively. ,

A rotary disk-type nitrification reaction tank which induces ammonia nitrogen removal and nitrification from the supernatant flowing from the primary precipitation tank;

A first anoxic tank for denitrifying the nitrate nitrogen flowing in the nitrification tank and internally circulated from a subsequent second anoxic tank using activated sludge to which organic substances introduced from the primary precipitation tank are adsorbed,

An intermittent aeration reactor for denitrification of untreated nitrate nitrogen in the first anoxic tank, decomposing organic nitrogen introduced from the primary settling tank into ammonia nitrogen, and performing nitrification and denitrification of the decomposed ammonia nitrogen,

A second anoxic tank for further denitrification of the nitrified nitrate in the intermittent aeration reactor,

The main technical configuration is a wastewater treatment system using an internal circulation consisting of a re-aeration tank in which the denitrified nitrogen gas is degassed in the second anoxic tank and nitrification of residual ammonia nitrogen is carried out.

In addition, the rotary disk-type nitrification tank is provided with a rotating disk of a cylindrical structure arranged so that the disk-type disks overlap in the range of 2 to 200 sheets, the rotation disk is configured to be immersed in the waste water by 40 to 60% or 100% It is characterized by.

Hereinafter, the technical configuration will be described in more detail.

The contact tank is operated in aerobic or anaerobic state, it is usually operated as anaerobic, but is changed to aerobic operation if the sedimentation in the activated sludge separation tank is not good. The function of the contact tank is to adsorb organic and toxic substances contained in the waste water to the activated sludge, so that the nitrification bacteria can be smoothly carried out without toxic effects in the nitrification tank subsequent to the contact tank.

In the activated sludge, the extracellular polymer surrounding the surface of the activated sludge has an anion and most of the heavy metal has a cation, so when the activated sludge and the wastewater come into contact, the heavy metal of the cation is adsorbed onto the extracellular polymer. To be removed.

The primary sedimentation tank separates the activated sludge adsorbed with the organic substance and the supernatant liquid containing a large amount of ammonia, the supernatant is transferred to the nitrification reaction tank, and the activated sludge adsorbed with the organic substance is transferred to the first anoxic tank.

The rotating disk-type nitrification tank uses a rotating disk without filling the medium and filling therein. The planar shape of the rotating disk is circular and has a diameter of 3.0 to 4.0 m. Although the diameter may be used in excess of 4.0m, it is preferable to use a diameter of 3.0 ~ 4.0m due to assembly, transportation problems and the size limit of the jaw.

The thickness of the rotating disc is 0.7 ~ 2.0mm in the case of liethylene or vinyl chloride, 7mm in the case of polystyrene. Assembly of the rotating disc may be performed by coupling a cylindrical rotating disc arranged so that 2 to 200 sheets overlap the rotating shaft.

The rotating disk is to allow the rotating disk is immersed about 40 ~ 60% of its diameter or 100% completely immersed in the wastewater introduced into the rotary disk-type nitrification reactor.

When the rotary disc is locked to 40 to 60% in the wastewater, there is an advantage of not having to inject oxygen separately. This increases the nitrification efficiency and the amount of oxygen required is less than or similar to the amount of oxygen used to flow the suspended bile-mediated nitrifier.

In addition, by using a material having a small specific gravity, the rotating disc can minimize the power cost required while rotating while preventing the rotating shaft supporting the rotating disc, and the floating plate is floating in the water due to buoyancy. Therefore, even a small amount of oxygen supply can rotate the disc.

In addition, as a method for increasing the specific surface area of the rotating disc, the surface of the rotating disc is roughened, or activated carbon is added in the production of the rotating disc to increase the specific surface area.

As such, when a rotary disc is used instead of a wall and medium in the nitrification tank, the rotary disc rotates to supply air to the wastewater, and the biofilm is naturally detached from the surface of the rotary disc by the rotational friction force, thereby causing a separate backwashing process. You do not need this.

The first anoxic tank functions to effectively perform denitrification by using activated sludge in which organic nitrate introduced from the first settling tank is adsorbed in a large amount by nitrate nitrogen introduced into the nitrification tank and the second anoxic furnace. .

The intermittent aeration tank is characterized by denitrification of nitrate nitrogen which has not been treated in the first anoxic tank, decomposition with ammonia nitrogen of organic nitrogen flowing from the primary settling tank, and then nitrification and denitrification of the decomposed ammonia nitrogen. Do this.

The second anaerobic bath is where further denitrification of the nitrated nitrate occurs in the intermittent aeration reactor.

The reaeration tank is degassed in the denitrified nitrogen gas of the second anoxic tank, and nitrification of residual ammonia nitrogen is performed.

As described above, the low C / N ratio sewage treatment process using the internal circulation and the rotating disk-type nitrification tank according to the present invention, the DEPHANOX process and the present inventors have applied for a patent and registered patent (10-0640940) Complementing the shortcomings of 2006.11.06) provides a biological treatment process designed for more complete nitrogen treatment.

In addition, instead of filling the fixed bed, suspended and fluidized bed walls and medium in the nitrification tank and using it for nitrification, as shown in Figs. Since the biofilm can be naturally detached from the surface of the membrane, the backwashing process, which is essential for the use of suspended and fixed bed walls and media, can be omitted, and the walls and media that may occur when fluid beds and media are used do not flow. It is effective to prevent the phenomenon.

In addition, in the case of the reaction tank using the fluidized bed and the medium, the amount of air for circulating the fluidized bed and the medium is required to be higher than the amount of air required for the reaction. can do.

In addition, eliminating the backwashing process facilitates the operation and management of the process and reduces the economic cost of the backwashing process. In addition, it is possible to expect a stable high nitrification efficiency because it is possible to prevent the phenomenon of precipitation and precipitation without the flow that can occur when using the fluidized bed.

With reference to the contents shown in Figure 2 or 3 will be described a specific embodiment of the wastewater treatment system using the internal circulation and the rotating disk-type nitrification tank.

Example 1

By adsorbing organic substances and toxic substances contained in the influent wastewater using activated sludge, the contact operated in aerobic or anaerobic state so that the subsequent nitrification bacteria of the nitrification tank can be subjected to nitrification without being affected by the toxic substances. After passing through the tank (1), the influent wastewater is transferred to the primary settling tank (2). The primary sedimentation tank (2) separates the activated sludge adsorbed with organic matter and the supernatant containing a large amount of ammonia from the wastewater passed through the contact tank (1), and the supernatant is a nitrification reaction tank (3). Each is transported to the first anaerobic tank 4.

In addition, the rotary disk-type nitrification tank 3 installed at the rear end of the primary settling tank 2 induces ammonia nitrogen removal and nitrification from the supernatant flowing from the primary settling tank. Rotating disc 200 of the cylindrical structure is installed in the) is configured to be immersed in the waste water 40%.

 As such, when the rotary disc 200 is configured to be immersed in 40% of the waste water, there is no economical advantage in operating the air into the waste water in the rotary disc-type nitrification tank 3 separately.

Next, the first anoxic tank (4) installed at the rear end of the nitrification tank (3) receives nitrate nitrogen which is internally circulated from the nitrification tank and the subsequent second anoxic tank (6) from the primary precipitation tank (2). Denitrification is carried out using activated sludge adsorbed with a large amount of organic matter,

The intermittent aeration reaction tank 5 installed at the rear end of the first anoxic tank 4 denitrates the untreated nitrogen nitrate in the first anoxic tank and decomposes organic nitrogen introduced from the primary settling tank 2 into ammonia nitrogen. And nitrification and denitrification of the decomposed ammonia nitrogen.

In this way, the nitrate nitrated in the intermittent aeration reactor is further denitrified in the second anoxic tank (6) provided at the rear end of the intermittent aeration reactor (5).

Then, the denitrification of the nitrogen gas denitrified in the second anoxic tank (6) is performed, and the residual ammonia nitrogen is nitrified through the reaeration tank (7) installed at the rear end of the second anoxic tank (6). Efficient treatment of organic matter, nitrogen and phosphorus contained in high concentration organic wastewater such as urban sewage, livestock waste and industrial wastewater with low N ratio.

Example 2

By adsorbing organic substances and toxic substances contained in the influent wastewater using activated sludge, the contact operated in aerobic or anaerobic state so that the subsequent nitrification bacteria of the nitrification tank can be subjected to nitrification without being affected by the toxic substances. After passing through the tank (1), the influent wastewater is transferred to the primary settling tank (2). The primary sedimentation tank (2) separates the activated sludge adsorbed with organic matter and the supernatant containing a large amount of ammonia from the wastewater passed through the contact tank (1), and the supernatant is a nitrification reaction tank (3). Each is transported to the first anaerobic tank 4.

In addition, the rotary disk-type nitrification tank 3 installed at the rear end of the primary settling tank 2 induces ammonia nitrogen removal and nitrification from the supernatant flowing from the primary settling tank. Rotating disc 200 having a cylindrical structure installed in the) is configured to be immersed in the waste water 100%.

As such, when the rotational disc 200 is completely locked to 100%, the contact time between the microorganisms required for nitrification and waste water is increased, thereby increasing the nitrification efficiency. In this way, when the rotary disk 200 is to be immersed in the waste water 100%, the air is injected into the waste water of the rotary disk-type nitrification tank (3).

Next, the first anoxic tank (4) installed at the rear end of the nitrification tank (3) receives nitrate nitrogen which is internally circulated from the nitrification tank and the subsequent second anoxic tank (6) from the primary precipitation tank (2). Denitrification is carried out using activated sludge adsorbed with a large amount of organic matter,

The intermittent aeration reaction tank 5 installed at the rear end of the first anoxic tank 4 denitrates the untreated nitrogen nitrate in the first anoxic tank and decomposes organic nitrogen introduced from the primary settling tank 2 into ammonia nitrogen. And nitrification and denitrification of the decomposed ammonia nitrogen.

In this way, the nitrate nitrated in the intermittent aeration reactor is further denitrified in the second anoxic tank (6) provided at the rear end of the intermittent aeration reactor (5).

Then, the denitrification of the nitrogen gas denitrified in the second anoxic tank (6) is performed, and the residual ammonia nitrogen is nitrified through the reaeration tank (7) installed at the rear end of the second anoxic tank (6). Efficient treatment of organic matter, nitrogen and phosphorus contained in high concentration organic wastewater such as urban sewage, livestock waste and industrial wastewater with low N ratio.

1 is a schematic view showing a conventional wastewater treatment system.

Figure 2 is a schematic diagram showing a wastewater treatment system according to a first embodiment of the present invention.

Figure 3 is a schematic diagram showing a wastewater treatment system according to a second embodiment of the present invention.

4 is a sectional view showing a rotating disc according to the present invention.

Explanation of symbols on the main parts of the drawings

1: contact tank

2: 1st precipitation precursor

3: nitrification tank

4: the first anaerobic tank

5: intermittent aeration reactor

6: second anaerobic tank

7: reaeration

8: terminal sedimentation precursor

100: floating wall and media

200: rotating disc

Claims (4)

By adsorbing organic substances and toxic substances contained in the influent wastewater using activated sludge, the contact operated in aerobic or anaerobic state so that the subsequent nitrification bacteria of the nitrification tank can be subjected to nitrification without being affected by the toxic substances. Joe (1), After separating the activated sludge adsorbed with organic matter and the supernatant containing a large amount of ammonia from the wastewater passed through the contact tank (1), the supernatant was transferred to the nitrification reaction tank (3), and the activated sludge was transferred to the first anoxic tank (4), respectively. A primary precipitation tank 2 having a function of conveying, A rotary disk-type nitrification reactor (3) for inducing ammonia nitrogen removal and nitrification from the supernatant flowing from the primary precipitation tank (2), The denitrification is carried out using the activated sludge in which the nitrate nitrogen flowing from the nitrification reaction tank 3 and circulating internally from the subsequent second anoxic tank 6 is introduced, and the organic material flowing from the primary precipitation tank 2 is adsorbed in large quantities. The first anoxic tank 4 to be treated, Denitrification of untreated nitrogenous nitrate in the first anoxic tank (4) and organic nitrogen flowing from the primary settling tank (2) are decomposed into ammonia nitrogen, and nitrification and denitrification of the decomposed ammonia nitrogen are performed. Intermittent aeration reactor (5) A second anoxic tank (6) for further denitrification of the nitrified nitrate in the intermittent aeration reaction tank (5), A waste water treatment system using an internal circulation and a rotating disk-type nitrification tank, characterized in that the denitrified nitrogen gas is degassed in the second anoxic tank (6) and composed of a reaeration tank (7) in which nitrification of residual ammonia nitrogen is carried out. . According to claim 1, the rotary disk-type nitrification tank 3 is arranged so that the disk-type disks overlap in the range of 2 to 200 sheets so that the rotating disk 200 having a cylindrical structure is immersed in 40 ~ 60% in the waste water. Wastewater treatment system using an internal circulation and a rotating disk-type nitrification reactor characterized in that. The wastewater treatment system according to claim 2, wherein the rotating disc 200 is configured to be immersed in 100% of the wastewater. 4. The wastewater treatment system according to claim 3, wherein when the rotating disc 200 is locked to 100% in the wastewater, air is injected into the wastewater.

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