KR100607719B1 - Wastewater treatment system using oxidation ditch - Google Patents

Abstract

The present invention relates to a sewage treatment apparatus by the oxidation sphere method,

Reduced land area by installing sedimentation basins and oxidizing spheres in one piece,

By reaeration of sludge generated in the sedimentation basin and conveyed to the inlet of the oxidizing sphere, the organic matter removal and nitrification efficiency are improved,

By installing and operating an underwater aerator and stirrer, it is possible to remove nitrogen and phosphorus,

By installing a variable outflow ware at the sedimentation basin, it is possible to cope with a severe fluctuation in inflow flow rate.

By treating the sedimentation supernatant with water, the treated water can be reused and can be efficiently applied to sewage treatment in tourism complexes, schools and villages.

Swirl flow type pretreatment, Oxidation reactor, Sludge reaeration tank, Variable spill wear

Description

Sewage Treatment System by Oxidation Method {Wastewater Treatment System Using Oxidation Ditch}

1 is a conceptual diagram of sewage treatment by a general oxidation sphere method,

2 is a process flowchart of the sewage treatment by the oxidation sphere method of the present invention;

3A, 3B are a front view and a partial plan view showing the overall configuration of the sewage treatment apparatus according to the oxidation sphere method of the present invention;

4 is a partial cross-sectional view of an airlift system applied to the present invention;

5 is a partial cross-sectional view of the variable leakage wear in accordance with the present invention.

Brief description of symbols for the main parts of the drawings

 4: sedimentation separation liquid 5: sedimentation tank

 6: underwater aerator 7: agitator

 9: slant plate 10: sludge hopper

11: variable spill wear 15: sludge return piping

16, 16 ', 16' ': Air Lift System

31: buoy 32: buoy support

34: Pin to prevent injury 35: Shaft

100: swirl flow pretreatment 110: swirl flow sediment remover

200: sedimentation separator 300: oxidation sphere

400: sedimentation basin 500: sludge storage tank

600: sludge reaeration tank

The present invention relates to a sewage treatment apparatus by the oxidation sphere method,

Reduced land area by installing sedimentation basins and oxidizing spheres in one piece,

By reaeration of sludge generated in the sedimentation basin and conveyed to the inlet of the oxidizing sphere, the organic matter removal and nitrification efficiency are improved,

By installing and operating an underwater aerator and stirrer, it is possible to remove nitrogen and phosphorus,

By installing a variable outflow ware at the sedimentation basin, it is possible to cope with a severe fluctuation in inflow flow rate.

By treating the sedimentation supernatant with water, the treated water can be reused and can be efficiently applied to sewage treatment in tourism complexes, schools and villages.

In general, the sewage treatment by the oxidative sphere method does not install a primary sedimentation basin, as shown in FIG. 1, aeration is performed by a mechanical aeration apparatus using a reaction tank of an elliptical channel, and a bottom part in which solid-liquid separation is performed in a secondary sedimentation basin. In the lower-type activated sludge process, the mechanical aeration device not only supplies oxygen for treatment but also mixes and stirs activated sludge in the oxidizing sphere and the influent sewage, and gives a flow rate to the mixed solution to circulate the oxidizing sphere so that the activated sludge does not settle. Has the function to

The following are some of the main known methods of sewage treatment by the oxidative sphere method.

First, the Schreiber method, which removes organic matter and nitrogen by aerobic / oxygen-free, maintains the state in the reactor as aerobic / oxygen-free by installing a rotating apparatus in a circular oxidizing sphere using a standard activated sludge method. Although the removal efficiency is excellent, the nitrification / denitrification efficiency is lower than the intermittent aeration operation due to the continuous aeration operation.

In the form of elliptical oxidizing sphere, the inflow and outflow is made on the center of the oxidizing sphere, and in the oxygen supply, the Orbal-Simpre method, which does not require a separate bulkhead, consists of a nitrification and denitrification zone by tubular flow using a mechanical horizontal rotor. On the other hand, it is strong against fluctuations in flow rate, and the complicated flow path requires excessive civil construction cost and site area, and it is not only low efficiency of removing nitrogen and phosphorus by regular aeration operation but also high power cost.

In addition, an anaerobic selection tank is installed at the front end as an improvement of the existing oxidizing sphere method, and the oxidizing sphere is operated periodically as an anaerobic tank and aerobic tank. Since the sludge is introduced into the oxidizing sphere under anoxic conditions, there is a defect that the intake efficiency of phosphorus may be lowered because the microorganisms are not sufficiently activated.

Finally, the PhICD method, which is a method of removing organic matter, nitrogen and phosphorus by repeatedly operating two or more built-in settler oxidizers having built-in settler in the oxidizing sphere, and repeatedly operating anoxic and aerobic aeration and changing the flow path, is performed in the PID process. Similarly, the objective differentiation is insufficient, and two or more reactor configurations are required.

In summary, the constituent features of the various oxidative sphere methods, in most oxidative sphere methods except the PhICD method, are composed of external sedimentation basins. The horizontal aeration type aerator is used. When the inflow rate of the oxidizer is decreased, the level of the oxidizer is lowered, so that the effective aeration is difficult. Therefore, the treatment efficiency of the oxidizer is lowered. The sludge is prevented from settling by circulating the oxidizing sphere by imparting a flow rate to it, but the effect is not large.

The present invention has been studied to solve all the problems of the conventional sewage treatment method by the oxidative sphere method,

SUMMARY OF THE INVENTION An object of the present invention is to provide a sewage treatment apparatus using an oxidation sphere method that can cope with a large fluctuation in the flow rate of sewage inflow, capable of highly treating nitrogen or phosphorus, and reusing treated water.

In order to achieve the above object, the present invention,

Reduced land area by installing sedimentation basins and oxidizing spheres in one piece,

By reaeration of sludge generated in the sedimentation basin and conveyed to the inlet of the oxidizing sphere, the organic matter removal and nitrification efficiency are improved,

By installing and operating an underwater aerator and stirrer, it is possible to remove nitrogen and phosphorus,

By installing a variable outflow ware at the sedimentation basin, it is possible to cope with a severe fluctuation in inflow flow rate.

By filtering the sedimentation supernatant, the treated water can be reused, and can be efficiently applied to sewage treatment in tourism complexes, schools and villages.

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

2 is a process flowchart of sewage treatment by the oxidative sphere method of the present invention;

The sewage introduced into the sewage treatment plant is removed from the swirl flow type pretreatment 100, and after the contaminants and sand are removed, the sewage is introduced into the oxidizing sphere 300, and the organic matter, nitrogen and phosphorus are removed, and the sewage is integrally installed in the oxidizing sphere 300. It is introduced into the sedimentation basin 400.

The supernatant from the sedimentation basin 400 is discharged to the filter paper 700 through the variable outflow wear 11 and filtered, and then flows into the disinfection tank 800. Disinfection in the disinfection tank 800 follows the existing sewage disinfection method using chlorine or ultraviolet rays, and the sewage passing through the disinfection tank 800 is discharged or stored in the reuse tank 900 for reuse.

On the other hand, the sludge precipitated in the sedimentation basin 400 is transferred to the sludge storage tank 500 and sent to the sludge reaeration tank 600 as necessary, the excess sludge is concentrated, as in the conventional sludge treatment process for sludge treatment ( 1000) and dehydrator 1100 is finally disposed of through the concentration and dehydration process.

The sludge sent to the sludge reaeration tank 600 is re-aerated and then returned to the oxidation sphere 300.

In addition, the sand sedimented in the spiral flow type pre-processor 100 is lifted by the air lift system to the sedimentation separator 200 and separated into sand and water 4 (hereinafter, referred to as sedimentation separation liquid), and the sand is the sedimentation discharge tank ( 5 are collected and carried out, and the sedimentation separation liquid 4 is conveyed to the oxidation sphere 300.

3A and 3B are front and partial plan views showing an overall configuration of the sewage treatment apparatus according to the oxidation sphere method of the present invention;

The sewage introduced by the pump (1) is removed after the coarse contaminants are removed from the screen (2) of the spiral flow type pretreatment (100), the sand in the swirl flow sediment remover (110) to the portion where the tornado block (3) is installed It is settled and lifted by the airlift system 16 to the sedimentation separator 200. At this time, to increase the lifting efficiency, the tornado block 3 of Utility Model Registration No. 328098 developed by the present applicant is installed at the bottom of the swirl flow sediment remover 110. This tornado block 3 removes the dead space in the erosion hopper, and provides the fluidity to the sand accumulated during salvage salvage function to maximize the saliva salvage.

And in the sedimentation separator 200, the sedimentation separation liquid 4 and sand are separated, and the sedimentation separation liquid 4 is sent to the oxidation sphere 300, and the sand is collected in the sedimentation discharge tank 5 for carrying out. The airlift system 16 will be described in detail with reference to FIG. 4.

The sewage pretreated in the swirl flow pretreatment 100 is introduced into the oxidation sphere 300. The oxidation sphere 300 is provided with an underwater aerator 6 and a stirrer 7.

The underwater aerator 6 forms an aerobic condition in the oxidizing sphere 300 to promote nitrification and phosphorus absorption by microorganisms present in the sewage, and the sewage gradually decreases the dissolved oxygen concentration while circulating the oxidizing sphere 300. Just before reaching the point where the underwater aerator 6 is installed, the dissolved oxygen concentration is minimal. At this point nitrogen is removed (denitrification) and the microorganisms release phosphorus. During this cycle, the microorganisms ingest more phosphorus in aerobic state than the amount of phosphorus released and can remove phosphorus by discarding the microorganisms ingested with excess sludge as excess sludge (dephosphorus).

Here, the use of the underwater aerator 6 and the stirrer 7 in the oxidation sphere 300 is one of the features of the present invention.

First, in the conventional oxidizing sphere method, a horizontal axle type aerator is mainly used as an aerator. In this case, when the water level decreases when the inflow flow rate decreases, the aeration efficiency decreases and nitrogen or phosphorus treatment is not performed properly. However, in the present invention, by using the underwater aerator 6, the aeration is made from the depth of the oxidation sphere 300, so even if the fluctuations in the water level is not affected by the sewage circulating the oxidation sphere 300 Oxygen transfer is possible.

Secondly, in the related art, the flow rate is mainly provided by operating the aerator to maintain the flow rate so that sludge does not settle in the oxidizing sphere 300. However, in the conventional transverse aeration machine, it is difficult to expect an increase in the flow rate due to the aeration to the depth of the oxidizing sphere 300, and also to increase the number of installation of the aerator to increase the flow rate reduces the removal efficiency of nitrogen and phosphorus There is a risk of making. Therefore, in the present invention, by using the stirrer 7 to maintain the flow rate in the deep portion of the oxidizing sphere, the sludge can be prevented without affecting the removal efficiency of nitrogen and phosphorus.

On the other hand, the oxidation sphere 300, the sedimentation basin 400, the sludge storage tank 500, the sludge reaeration tank 600 is integrally installed. Sewage circulating the oxidizing sphere 300 is introduced into the settling basin 400, the sludge collector 8 and the inclined plate 9 for improving the settling efficiency is installed.

In the present invention, by installing a non-metal sludge collector (KT No. 0670), which was developed by the company as a sludge collector and approved by the new domestic technology KT, KT 0670 was intended to prevent corrosion of the device.

The sludge from the sedimentation basin 400 is stored in the sludge hopper 10, and the supernatant of the sedimentation basin 400 is discharged 12 into the disinfection tank 800 through the filter paper 700 through the variable effluent wear 11. The variable leakware 11 will be described with reference to FIG. 5.

The sludge stored in the sludge hopper 10 is transferred to the sludge storage tank 500 by the air lift system 16 ′. The sludge in the sludge storage tank 500 is introduced into the sludge reaeration tank 600 by the required amount (13), and the excess sludge is discharged to the sludge treatment step (14). The re-aerated sludge is oxidized through the sludge conveying pipe 15 (300)

To return. The sludge conveyed in this way can effectively remove organic matters in the sewage by conveying the microorganisms because the microorganisms are maximized by reaeration.

Herein, the mechanism of removing organic substances, nitrogen, and phosphorus from the oxidizing sphere 300 will be described in detail.

At the inlet of the oxidizing port 300 into which sewage flows, an aerobic area is formed by the operation of the underwater aerator 6. In the aerobic region, ammonia nitrogen (NH ₄ ⁺ -N), which is converted from organic nitrogen present in sewage, is nitrite nitrogen (NO ₂ ^-- N) and nitrates by Nitrosomonas and Nitrobacter. is oxidized to the ^- (-N NO ₃₎ nitrogen.

The nitrification process at this time is as follows.

Step ^{_{1: NH 4 + + 3 /}} 2O₂ → NO 2 - + H 2 O + 2H +

Step ^{_{2: NO 2 - + 1 /}} 2O 2 → NO 3 -

General ^{_{reaction: NH 4 + + 2O 2 →}} NO 3 - + H 2 O + 2H +

Oxygen supplied by the underwater aerator 6 at the inlet of the oxidizer 300 is gradually consumed while circulating the oxidizer 300, and finally forms an oxygen free zone without oxygen. In anoxic zones, nitrite nitrogen (NO ₂ ^-- N) and nitrate nitrogen (NO ₃ ^-- N) are reduced to N ₂ gas by nitrite breathing and nitrate breathing by denitrification. The denitrification process at this time is as follows.

Nitrite ^{_{respiration: 2NO 2 - + 3H 2 →}} N 2 + 2OH - + 2H 2 O

Nitrate ^{_{respiration: 2NO 3 - + 5H 2 →}} N 2 + 2OH - + 4H 2 O

In the above reaction, H ₂ is obtained from a hydrogen donor (substrate). This hydrogen donor is supplied by decomposition of organic matter in sewage and deposits in microbial systems. If these hydrogen donors are scarce, external carbon sources such as methanol must be supplied.

Herein, the reaeration process of the sludge which is a feature of the present invention, and the meaning of conveying the reaerated sludge to the oxidizing tool 300 will be described.

First, re-aeration of the sludge is to allow the microorganisms in the sludge to maximize the growth by ingesting the organic matter contained in the sludge as nutrients. Microorganisms in the sludge continue to multiply by using oxygen and organic matter as energy sources, eventually reaching a state in which organic matter used as nutrients for microorganisms is insufficient, and some microorganisms may be assetd due to nutrient deficiency. Re-aeration of sludge improves nitrification efficiency, and thus has the advantage of ensuring stable treatment efficiency even at low water temperatures in winter, when microbial activity is low.

Secondly, by returning 15 the reaerated sludge placed in this state to the oxidizing sphere 300, the microorganisms actively ingest the organic matter contained in the inflowing sewage, and thus the organic matter removal efficiency is significantly improved than the conventional method. Can be. In addition, the sludge returned to the oxidation sphere 300 may be used as a carbon source for supplying a hydrogen donor required for the denitrification process, thereby improving the denitrification efficiency and reducing the cost of supplying an external carbon source.

Microorganisms are known to ingest phosphorus (jeongphosphoric acid) present in sewage in aerobic state and accumulate as polyphosphoric acid in cells, and hydrolyze and release polyphosphoric acid accumulated in cells as anaphosphoric acid in anaerobic state. When changing from anaerobic state to aerobic state, because phosphorus is ingested in aerobic state more than the amount of phosphorus released by microorganisms in the aerobic state, it can be discharged as excess sludge (14) to biologically remove phosphorus. have.

Therefore, in the present invention, by using this principle, in the aerobic region of the oxidizing sphere 300 by controlling the aeration amount of the underwater aeration machine 6 in the oxidizing sphere 300 is known as the minimum dissolved oxygen concentration that the microorganism can sufficiently ingest phosphorus. It is possible to maximize the release of phosphorus by maintaining more than 2 mg / L and in the absence of oxygen or in the minimum in the oxygen free zone.

4 is a partial cross-sectional view of an airlift system applied to the present invention.

In the present invention, the airlift system 16 (16 ') 16' 'is used to lift the sand settled in the swirl flow sediment remover 110 and to transfer the settling sludge and the reaeration sludge. Airlift systems 16 (16 ') 16' 'are configured with tornado block 3. The tornado block 3 is installed at the bottom of the swirl flow sediment remover 110 and has an effect of eliminating the dead zone where the sediment is not lifted. When sprayed through the nozzle 22 installed in the (25), the flow is generated (24) in the sand settled above the tornado block (3), so that all the sediment is sucked into the suction chamber 25 is discharged (23) .

5 is a partial cross-sectional view of the variable leakage wear 11 according to the present invention,

Variable outflow wear 11 is one of the features of the present invention is equipped with a buoy 31 on both sides of the outflow wear 11 to rise and fall according to the water level fluctuation of the sedimentation basin 400. The buoy 31 is fixed to the buoy support 32 on the wall of the sedimentation basin 400 so that it can be moved only up and down in the sedimentation basin 400. The volume of the buoy 31 is designed so that the constant water flows out of the sedimentation basin 400 at all times, even if the outflow ware 11 is locked to an appropriate depth from the surface of the sedimentation basin 400. Therefore, even if the flow rate fluctuates by installing the outflow ware 11 in a variable type, stable sedimentation treatment is possible.

However, since the variable outflow wear 11 in the present invention is designed to always discharge a constant flow rate, if the inflow flow rate is continuously increased, the level of the settling basin 400 also increases to eventually overflow the top of the settling basin 400. have. Therefore, in order to prevent such a point was installed on the bottom of the buoy 31, the injury blocking pin 34 for blocking further leakage wear injury. This is because when the inflow flow rate is continuously increased, by fixing the outflow ware 11 that floated in accordance with the rise in the water level in a certain position, the outflow ware 11 will continue to flow out the sedimentation basin supernatant water as the inflow flow rate increases It is effective to prevent the water level rise.

On the contrary, when the inflow flow rate is continuously reduced, the outflow ware 11 gradually moves downward from the sedimentation basin 400, and the shaft 35 fixing the outflow ware 11 and the buoy 31 is the buoy support 32. By being blocked by), the leaked wear 11 no longer goes down. As a result, it is possible to maintain a certain level of water in the oxidizing sphere 300, so that the microorganisms that remove organic matter and nitrogen and phosphorus in the sewage can survive, as well as the inclined plate installed to improve the precipitation efficiency in the sedimentation basin 400 ( The damage caused by collision with 9) can be prevented.

The treated water flowing out of the variable outflow wear 11 that operates on the same principle is discharged to the filter paper 700 through the corrugated pipe 33. As filter paper, TAB Filter (KT No. 1544) developed by the present applicant and recognized as a new domestic technology is used. The filtered treated water is sterilized in the disinfection tank 800 and then collected in a reuse tank 900 for being discharged or reused.

As described above, the sewage treatment apparatus according to the oxidation sphere method of the present invention can cope with any flow rate fluctuation by using the variable outflow wear 11 in the sedimentation basin 400, and can ensure a stable treatment efficiency,

It is possible to form aerobic conditions and anoxic conditions through aeration and agitation in the oxidizing sphere 300 to remove nitrogen and phosphorus,

By re-aeration and conveying the sludge, it is possible to maximize the microorganisms to maximize the removal of organic matter and the nitrification efficiency than the existing method, in particular, stable treatment is possible even in the low water temperature in winter.

And by installing the sedimentation basin 400 integrally with the oxidation sphere 300, the land area is very small compared to the sedimentation basin external oxidation sphere method, by installing the inclined plate 9 in the sedimentation basin 400, it is possible to improve the precipitation efficiency ,

By using airlift systems 16, 16 'and 16' 'for sand lifting and sludge transfer, they are more efficient than ever before and significantly reduce maintenance costs.

By using the underwater aerator 6, it is possible to effectively transmit oxygen to the water level fluctuation, and by operating the stirrer 7, it is possible to prevent the maintenance of the flow rate in the oxidation sphere 300 and the precipitation of sludge,

By treating the sewage treated by the oxidation ball 300 with filtration, reuse of the treated water is possible.

The sewage treatment apparatus according to the oxidative sphere method of the present invention is used for sewage treatment in places where fluctuations in flow rates are severe, such as tourist complexes, amusement parks, schools, etc., and sewage generated in various industrial complexes such as food processing, meat packaging, and milk processing. It is also applicable to treatment.

Claims (1)

In the known sewage treatment apparatus by the oxidation sphere method, A known tornado block 3 and an airlift system 16 are installed and a swirl flow sediment remover 110 for lifting sedimented sand; An aeration apparatus 300 installed with an underwater aerator 6 and an agitator 7 to prevent oxygen supply and sludge settling in the sewage pretreated by the swirl flow sediment remover 110; Integrally installed in the oxidation sphere 300, the inclined plate 9 is installed therein, connected to the buoy 31 inserted into the buoy support 32 on the wall by the shaft 35 is connected to the floating pin at the lower end A sedimentation basin 400 having a variable outflow wear 11 provided with 34; A sludge storage tank 500 installed integrally with the oxidizing sphere 300 and storing sludge lifted from the sludge hopper 10 of the sedimentation basin 400 to the air lift system 16 ′; The sludge reaeration tank 600 is integrally installed with the oxidizing sphere 300 and re-aerated a portion of the sludge in the sludge storage tank 500 to be conveyed back to the oxidizing sphere 300 by the air lift system 16 ''. The sewage treatment apparatus by the oxidation sphere method characterized by the above-mentioned.

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