KR20060096825A - Continual system for processing waste water - Google Patents

Abstract

The present invention relates to a wastewater treatment system, and more particularly, to effectively remove organic matter, nitrogen and phosphorus contained in high concentration organic wastewater, such as urban sewage, livestock waste, and industrial wastewater, which have a low C / N ratio. In order to improve the efficiency of nitrogen treatment by improving the efficiency of the process, anaerobic contact tank, activated sludge separation tank, nitrification reaction tank, anoxic denitrification reactor (first anoxic), intermittent aeration reactor, anoxic tank, reaeration tank, and sedimentation tank In order to maximize the efficiency of contacting organic matter and to place the intermittent reaction tank at the rear of the denitrification tank by reducing the concentration of total nitrogen discharged by contacting the returned activated sludge from the sedimentation tank to the anaerobic contacting tank without directly introducing the influent into the anaerobic contacting tank. Has

C / N ratio, nitrogen, wastewater treatment system.

Description

Wastewater Treatment System {CONTINUAL SYSTEM FOR PROCESSING WASTE WATER}

1 is a schematic diagram showing a wastewater treatment system according to an embodiment of the present invention.

       Explanation of symbols on the main parts of the drawings

           1: Inflow wastewater 2: Anaerobic contact tank

           3: activated sludge separation tank 4: nitrification reactor

           5: floating fence, medium 6: denitrification reactor

           7: Intermittent Aeration Reactor 8: Anaerobic Tank

           9: reaeration tank 10: sedimentation tank

 The present invention relates to a wastewater treatment system, and more particularly, to effectively remove organic matter, nitrogen and phosphorus contained in high concentration organic wastewater, such as urban sewage, livestock waste, and industrial wastewater, which have a low C / N ratio. In order to improve the efficiency of nitrogen treatment by improving the efficiency of the process, anaerobic contact tank, activated sludge separation tank, nitrification reaction tank, anoxic denitrification reactor (first anoxic), intermittent aeration reactor, anoxic tank, reaeration tank, and sedimentation tank In order to maximize the efficiency of contacting organic matter and to place the intermittent reaction tank at the rear of the denitrification tank by reducing the concentration of total nitrogen discharged by contacting the returned activated sludge from the sedimentation tank to the anaerobic contacting tank without directly introducing the influent into the anaerobic contacting tank. Has

In general, the nutrients contained in the waste water are inorganic elements, but they flow into rivers, coastal seas, lakes (lakes and reservoirs), etc. to promote algae growth and cause eutrophication.

In addition, when the nutrients contained in the wastewater enter the coastal seas, they cause red tide. If the nutrients are severely decayed at the bottom of the water and odors are generated, they promote water pollution. The substance to be removed before entering the appeal.

In Korea, most sewage and livestock wastewater treatment methods rely on activated sludge. Most suspended solids and organics can be removed by treatment with activated sludge, but only 20-40% of nutrients such as nitrogen and phosphorus are treated.

Processes for treating nutrients such as nitrogen and phosphorus include physical and chemical treatments and biological treatments.

First of all, the physical treatment methods include ammonia degassing, ion exchange using selective adsorption, precipitation of phosphorus using slaked lime and flocculant, and struvite formation of precipitation of nitrogen and phosphorus simultaneously. It is used. However, this method, although the treatment is made selectively, there are disadvantages such as temperature-sensitive and expensive. In addition, the chemical cost and the environment required for operation is difficult to operate because it is specific, and the runoff is unstable in the world as well.

On the other hand, in the biological treatment method, in the case of nitrogen, ammonia nitrogen and organic nitrogen in the dissolved state are nitrified by nitrifying bacteria (ie, Nitrosomonas & Nitrobacter ) under aerobic conditions, and ammonia is converted into nitrate form. Denitrification bacteria (ie, Pseudomonas, Paracoccus denitrifiers) are used as electron acceptors instead of oxygen under anoxic conditions, which are converted to nitrogen gas and released into the atmosphere (denitrification). For 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, causing the microorganism to overdose phosphorus, Phosphorus in the wastewater is removed by a gentle removal.

The degree of ingestion of the phosphorus of the microorganism in the aerobic condition depends on the amount and type of organic matter introduced into the anaerobic condition, especially in the case of maintaining the 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 is enhanced in subsequent aerobic conditions, 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 to induce organic oxidation and nitrification reaction and microorganism intake of phosphorus in the aerobic reactor, and in anaerobic and anoxic reactor Nitrate nitrogen is converted to nitrogen gas to induce denitrification and phosphorus release into 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, A ² / O process, and the like. These processes are operated in a steady-state state in which waste water passes through anaerobic and aerobic reaction tanks by separating and arranging the reaction tanks according to the presence or absence of oxygen, and it is possible to secure good water quality in general wastewater treatment. When treating sewage with low organic matter / nitrogen (C / N) ratio as in processes or Korea, there is a disadvantage that nitrogen and phosphorus removal efficiency may be lowered due to lack of organic matter during denitrification or anaerobic phosphorus release.

One way to overcome the problem of wastewater treatment with low C / N ratios is the DEPHANOX process developed in Italy. In this process, anaerobic contacting tanks and separation tanks are used for the adsorption of organic matter and induction 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 are not adsorbed. Nitrogen compounds are nitrified in separate reactors and sent to subsequent denitrification tanks for denitrification by microorganisms adsorbing organic matter. 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.

Despite these advantages of the DEPHANOX process, however, organic nitrogen and ammonia nitrogen flowing into the denitrification tank from the separation tank during the subsequent treatment after nitrification cannot be sufficiently decomposed or nitrified and discharged, and denitrification is carried out only in a single denitrification reactor following the nitrification tank. Because it is made, it has a disadvantage that can not expect high nitrogen removal efficiency.

In order to solve the above problems, the present inventors prior to the present invention, the patent application 10-2003-0054038 (application date: 2003.08.05) anaerobic contact tank (2), separation tank (3), nitrification reaction tank (4) , Denitrification reactor (6), intermittent aeration reactor (7), reaeration tank (8), sedimentation tank (9) or anaerobic contacting tank (2), separation tank (3), nitrification reactor (4), denitrification reactor (6) There is a filing for a wastewater treatment device consisting of an intermittent aeration reactor (7), an oxygen-free tank (8-1), and a precipitation tank (9),

The process has the disadvantage that the ammonia nitrogen is discharged without nitrification because there is no re-aeration tank at the rear end of the anoxic tank (8-1), there is a problem that the precipitation efficiency in the precipitation tank is lowered.

In order to solve the shortcomings of the existing DEPHANOX process and the problem of the patent application of the present invention, the present invention is one process for the process treated by intermittent aeration reactor, reaeration tank, precipitation tank or intermittent aeration reactor, anoxic tank, precipitation tank To provide a processing system that can be processed by. In other words, by installing the reaeration tank in front of the sedimentation tank to reduce the ammonia nitrogen discharged without nitrification and to increase the sedimentation efficiency in the sedimentation basin.

The present invention is a biological treatment process devised for a more complete nitrogen treatment by supplementing the disadvantages of the existing DEPHANOX process and the patent application of the present invention, Figure 1 is a schematic diagram showing the purification of waste water according to a preferred embodiment of the present invention. . Referring to Figure 1, the apparatus for performing the waste water purification process according to a preferred embodiment of the present invention is an anaerobic contact tank (2), activated sludge separation tank (3) arranged in series, the nitrification reactor (4) of aerobic state , Floating wall, medium (5), anoxic denitrification tank (6), intermittent aeration reactor (7), anoxic tank (8), reaeration tank (9), settling tank (10), and the influent wastewater (1) was returned. Flows into the line.

Referring to Figure 1, looking at the configuration of the present invention in more detail,

Activated sludge adsorbs the organic material flowing in the inflow wastewater (1) and uses it to denitrify it in the denitrification reactor (6). Anaerobic contact tank (2) to facilitate the nitrification process without being affected; and

The organic sludge from the anaerobic contact tank (2) serves to separate the activated sludge and the supernatant, and the supernatant containing ammonia is transferred to the nitrification tank (4), and the organic matter adsorbed on the activated sludge is denitrification (6). Activated sludge separation tank (3) serving to transfer to;

The nitrification of the ammonia nitrogen continuously introduced from the activated sludge separation tank 3 can be improved by using the floating fence and the medium 5 installed therein. A nitrification reactor (4) for inducing a flow into a tubular flow to remove ammonia nitrogen; and

A denitrification reactor (6) for denitrification of the nitrate nitrogen flowing from the nitrification reactor (4); and

Denitrification of the untreated nitrate nitrogen in the denitrification tank 6 serves to decompose the organic nitrogen flowing from the activated sludge separation tank 3 into ammonia nitrogen and decomposes the decomposed ammonia nitrogen and activated sludge separation tank. (3) an intermittent aeration reactor (7) for performing nitrification and denitrification of the ammonia nitrogen introduced from (3); and

It is connected to the intermittent aeration reactor (7) and denitrification of nitrate nitrate occurs in the intermittent aeration reactor (7), the role of purifying the denitrified nitrate, undecomposed organic nitrogen and ammonia nitrogen to the denitrification reactor through the internal circulation Anaerobic tank (8); and

A reaeration tank 9 connected to an oxygen-free tank 8, degassing the denitrified nitrogen gas and performing nitrification of residual ammonia nitrogen; and an organic matter, nitrogen and phosphorus contained in the organic wastewater through the settling tank 10 effectively. It can be removed.

In the present invention, the inflow wastewater 1 is adsorbed to the activated sludge returned from the settling tank 10 to the anaerobic contacting tank 2 by flowing into the conveying line, and the size of the anaerobic contacting tank 2 through this pre-organic adsorption mechanism. At the same time, it can maximize the adsorption of organic matter. Anaerobic contact tank (2) is to enable the activated sludge to adsorb the organic material flowing into the waste water to be used for denitrification in the denitrification reactor (6) and also to induce the release of phosphorus. Another important role of the anaerobic contact tank (2) is to adsorb the toxic substances upon influx of toxic substances so that the nitrification bacteria in the subsequent nitrification reactor (4) can perform the nitrification process smoothly without being affected by toxic effects.

Activated sludge separation tank (3) serves to separate the activated sludge adsorbed from the anaerobic contact tank and the supernatant, and the supernatant containing ammonia is transferred to the nitrification tank (4), and the organic matter adsorbed on the activated sludge is Transfer to the denitrification tank (6) is used to increase the denitrification efficiency.

At this time, the nitrification reaction tank 4 can increase the nitrification efficiency of the ammonia nitrogen continuously introduced from the activated sludge separation tank 3 by using the floating wall and the medium 5. It can be separated into two or three stages, leading to the flow of the flow path to the tubular flow to remove ammonia nitrogen more stably.

The denitrification tank 6 is made of denitrification of the nitrate nitrogen flowing from the nitrification tank 4, wherein the electron donor is provided from the organic material adsorbed to the activated sludge introduced from the activated sludge separation tank 3. If denitrification is not sufficient, denitrification efficiency can be increased by artificially injecting an external organic carbon source.

The intermittent aeration reactor 7 performs denitrification of untreated nitrate nitrogen in the denitrification reactor 6, and decomposes organic nitrogen introduced from the activated sludge separation tank 3 into ammonia nitrogen. Nitrification and denitrification of the ammonia nitrogen flowing from the nitrogen and activated sludge separation tank (3) is performed, and the reaeration tank of the existing DEPHANOX process is divided into an intermittent aeration reactor (7), an oxygen-free tank (8) and a re-aeration tank (9). This greatly increases the total nitrogen removal efficiency. In the existing DEPHANOX process, the reaeration tank is immediately followed by the denitrification tank, so that organic nitrogen and ammonia nitrogen flowing from the activated sludge separation tank to the denitrification tank are partially nitrified and nitrified nitric acid and nitrification are not. Organic nitrogen and ammonia nitrogen are simply released into the effluent, so the total nitrogen removal efficiency is low.

In the reaeration tank (9), the denitrification tank (6), the intermittent aeration reactor (7), and the anoxic tank (8) are degassed into the atmosphere to improve sludge settling in the settling tank (10), and a small amount of residual ammonia Nitrification of nitrogen is carried out.

The role of the sedimentation tank (10) is to separate the activated sludge and solid components and supernatant from the reaeration tank (9), the supernatant is discharged and the activated sludge and solid components are removed as waste sludge along the return line Some will flow into the anaerobic contact tank (2).

In constructing the wastewater treatment system for removing nitrogen, the intermittent aeration reactor (7), the oxygen-free tank (8), the re-aeration tank (9) by the arrangement in order, the existing intermittent aeration reactor through the oxygen-free, in the order of the settling tank. It has a nitrogen treatment efficiency that is superior to the wastewater nitrogen treatment efficiency which is treated or is processed in the order of the settling tank through the reaeration tank in the intermittent aeration reaction tank.

Claims (2)

Activated sludge adsorbs the organic material introduced in the inflow wastewater (1) and uses it to denitrify it in the denitrification reactor (6). Anaerobic contact tank (2) to facilitate the nitrification process without being affected; and The organic sludge from the anaerobic contact tank (2) serves to separate the activated sludge and the supernatant, and the supernatant containing ammonia is transferred to the nitrification tank (4), and the organic matter adsorbed on the activated sludge is denitrification (6). Activated sludge separation tank (3) serving to transfer to; The nitrification of the ammonia nitrogen continuously introduced from the activated sludge separation tank 3 can be improved by using the floating fence and the medium 5 installed therein. A nitrification reactor (4) for inducing a flow into a tubular flow to remove ammonia nitrogen; and A denitrification reactor (6) for denitrification of the nitrate nitrogen flowing from the nitrification reactor (4); and Denitrification of the untreated nitrate nitrogen in the denitrification tank 6 serves to decompose the organic nitrogen flowing from the activated sludge separation tank 3 into ammonia nitrogen and decomposes the decomposed ammonia nitrogen and activated sludge separation tank. (3) an intermittent aeration reactor (7) for performing nitrification and denitrification of the ammonia nitrogen introduced from (3); and It is connected to the intermittent aeration reactor (7) and denitrification of nitrate nitrate occurs in the intermittent aeration reactor (7), the role of purifying the denitrified nitrate, undecomposed organic nitrogen and ammonia nitrogen to the denitrification reactor through the internal circulation Anaerobic tank (8); and A reaeration tank 9 connected with the oxygen-free tank 8, in which denitrification of the denitrified nitrogen gas is performed and nitrification of residual ammonia nitrogen is performed; and Waste water treatment system, characterized in that consisting of a settling tank (10). The nitrification tank 4 according to claim 1, wherein Enhance the nitrification efficiency of ammonia nitrogen continuously introduced from the activated sludge separation tank (3) and separate it into two or three stages as needed, and remove the ammonia nitrogen more stably by inducing the flow of the flow path into the tubular flow. Waste water treatment system, characterized in that possible.

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