KR100456346B1 - The sewage and waste water treatment plant by microorganism contact oxidation - Google Patents

Abstract

The present invention relates to a wastewater treatment apparatus, and aims to maximize the removal efficiency of organic matter, nutrients such as phosphorus and nitrogen by improving the conventional catalytic oxidation method.

In order to achieve the above object, the present invention provides a flow regulating tank (10) having a sewage and wastewater inflow pipe (11) for introducing sewage and wastewater collected in a relay pumping station or a sump; The first waste portion 21 is formed with a waste water transport pipe 211 connected to the flow rate adjustment tank 10 at an upper end thereof, and a diffuser 212 configured to abandon the introduced waste water by blowing air. The inlet hole 231 is separated by the first aeration part 21 and the partition wall 23, and the inflow hole 231 through which the waste water discarded is introduced is formed in the lower part of the partition wall 23. A first aeration tank (20) having a first contact portion (22) formed with a contact material (221) for processing by means of; A through hole 311 is formed in the upper portion through which the treated water flows from the first contact portion 22, and a diffuser 312 is formed in the lower portion to give up the treated water introduced through the through hole 311. The inlet hole 331 which is separated by the two aeration part 31, the said 2nd aeration part 31, and the partition 33, and in which the discarded process water flows is formed in the lower part of the partition 33, A second aeration tank (30) having a second contact portion (32) formed with a contact material (321) for treating the treated water by microorganisms; A settling tank (40) having a discharge pipe (42) for retaining the treated water transferred through the treated water transport pipe (41) connected to the second contact portion (32) to settle the sludge and discharge the supernatant water to the outside; And a sludge drawing tube 51 for drawing sludge precipitated in the settling tank 40, and storing the drawn sludge and concentrating and transporting the sludge storage tank 50 to a separate sludge concentration tank. In the used sewage and wastewater treatment apparatus, a sludge conveying pump 34 and a sludge conveying pipe 341 for conveying the sludge deposited in the lower portion to the first aeration part 21 are formed in the second aeration tank 30. , The sludge transfer pump 24 and the sludge transfer pipe 241 for transferring a portion of the sludge precipitated in the lower portion to the sludge storage tank 50 is formed in the first aeration tank 20 Provide a wastewater treatment device.

Description

Wastewater treatment apparatus using microbial contact oxidation method {The sewage and waste water treatment plant by microorganism contact oxidation}

The present invention relates to a wastewater treatment apparatus, and more particularly, to improve the microbial contact oxidation method, which is one of the conventional methods for treating domestic wastewater and industrial wastewater, to maximize the treatment efficiency of wastewater. The present invention relates to a wastewater treatment system using a catalytic oxidation method.

In recent years, due to the rapid development of the industry and population increase, water pollution is very serious. The main culprit of the water pollution is nutrients such as nitrogen and phosphorus including organic substances contained in the wastewater and wastewater. In particular, as the inflow of nutrients into rivers and lakes is greatly increased, the water supply is rapidly polluted, and accordingly, there is a demand for developing technologies for treating nutrients present in wastewater and wastewater and strengthening emission regulations.

As a method of treating organic matter and nutrients such as nitrogen and phosphorus present in the wastewater and wastewater, physical treatment methods, biological treatment methods and chemical treatment methods are known. Currently, wastewater treatment is performed using biological treatment methods.

The biological treatment method is an activated sludge method for treating wastewater by using sludge in which microorganisms exist, and the activated sludge method is usually transferred to an aeration tank by introducing the sewage / wastewater into an aeration tank, followed by a settling tank. It is transported and settled, but the precipitated sludge is returned to the aeration tank and the supernatant is discharged.

However, the activated sludge method is difficult to cope with load fluctuations, and when nitrogen and phosphorus are high in organic wastewater, nitrogen and phosphorus removal efficiency is poor.

Accordingly, there is known a catalytic oxidation method in which the activated sludge method is improved, and the catalytic oxidation method is a method of treating wastewater and waste water by throwing a contact material fixed with microorganisms into an aeration tank.

1 shows a schematic diagram of a wastewater treatment system by a catalytic oxidation method, which is generally used in the prior art. As shown in the drawing, the wastewater treatment apparatus of the prior art is collected in a conventional relay pump station or a sump. A flow rate adjusting tank 110 in which a waste water inflow pipe 111 is formed therein; The waste water transfer pipe 121 connected to the flow rate adjustment tank 110 is formed, and at the lower end, an diffuser 122 is formed to eject air supplied from an external blower to abandon the introduced waste water. An aeration tank 120 having a contact material 123 to which microorganisms in contact with the waste water are fixed; The treated water transfer pipe 131 connected to the aeration tank 120 is formed, the treated water transferred through the treated water transfer pipe 131 to settle the sludge, and has a discharge pipe 132 for discharging the symbol water to the outside Settling tank 130; And a sludge drawing pipe 141 for drawing sludge precipitated in the settling tank 130, and a sludge conveying pipe 142 for conveying a portion of the drawn sludge to the aeration tank 120, and a residual amount of sludge. The sludge storage tank 140 is transported to the sludge concentration tank for disposal.

In the wastewater treatment method using the wastewater treatment device having such a configuration, an inflow step of transferring the wastewater collected in the relay pumping station or the sump to the flow regulating tank 110 through the wastewater inflow pipe 111. Wow; The waste water of the flow rate adjusting tank 110 is transferred to the aeration tank 120 in which the contact material 123 is embedded through the waste water transport pipe 121 and then abandoned and at the same time to the microorganisms attached to the contact material 123. Aeration step of purifying by; A settling step of transferring the discarded treated water to the settling tank 130 to settle the sludge contained in the treated water; Part of the precipitated sludge is returned to the aeration tank 120 through the sludge conveying pipe 142, a part is transported to the sludge storage tank 140 and disposed of, and the purified symbol water is discharged through the discharge pipe 132 It consists of steps.

The aeration tank 120 for the aeration step is formed with a diffuser 122 at the lower end as shown, the contact member 123 is fixed to the microorganism is formed on the top. Air is continuously supplied to the diffuser 122 through an external blower so that aeration occurs in the aeration tank 120. When aeration is made, the waste water is brought into contact with the microorganisms stuck to the contact material 123, and the organic matter contained in the waste water is oxidized.

As microbial fixed contact material 123 formed inside the aeration tank 120, honeycomb (honey com), porous ceramic balls, and HBC are mainly used. Recently, HBC contact material having high contact area and high processing efficiency is mainly used. I use it.

This waste water treatment method is due to the increase in the amount of microorganisms in the aeration tank 120 due to the growth of microorganisms adhered to the contact material 123 formed in the aeration tank 120, the treatment efficiency is not only improved compared to the existing activated sludge method, but also contact materials By using (123), the amount of excess sludge is reduced, and the cost reduction by the sludge treatment can be seen.

However, in the wastewater treatment method described above, as microbubbles are supplied to the entire contacting material 123 by abandonment, a phenomenon in which microorganisms are detached from the contacting material 123 occurs, thereby obtaining a treatment efficiency of nutrients maximized. There is a problem that the nitrogen and phosphorus removal efficiency is very low.

Accordingly, the present invention is to solve the above problems, the wastewater treatment apparatus using the microbial contact oxidation method to improve the conventional catalytic oxidation method to maximize the removal efficiency of organic matter, nutrients such as phosphorus and nitrogen. The purpose is to provide.

1 is a schematic view of a wastewater treatment apparatus by a conventional microbial contact oxidation method.

2 is a schematic view of a wastewater treatment apparatus according to an embodiment of the present invention.

3 is an enlarged view of the aeration tank shown in FIG.

4 is a view showing a wastewater treatment process according to the present invention.

<Explanation of symbols for the main parts of the drawings>

10: flow adjustment tank

11: Wastewater inflow pipe

20: First Gibbon

21: first abandonment 211: waste water transport pipe 212: diffuser

22: first contact portion 221: contact member 23: partition

231: inlet hole 24: sludge transfer pump 241: sludge transfer pipe

30: 2nd Gigi

31: second aeration portion 311: through hole 312: diffuser

32: second contact portion 321: contact material 33: partition wall

331: inlet hole 34: sludge conveying pump 341: sludge conveying pipe

40: sedimentation tank

41: treated water transfer pipe 42: discharge pipe 43: central pipe

44: filtration layer 45: scraper

50: sludge storage tank

51: sludge drawing pipe

S1: Inflow stage S2: Primary aeration stage S3: Primary treatment stage

S4: Secondary aeration stage S5: Secondary treatment stage S6: Discharge stage

The present invention to achieve the above object

A flow rate adjustment tank in which a wastewater inflow pipe for introducing wastewater and wastewater collected in a relay pumping station or a sump is formed;

A wastewater conveying pipe connected to the flow regulating tank is formed at an upper end thereof, and is separated by a first aeration unit having a diffuser formed at the lower portion of the waste pipe to abandon the introduced wastewater; A first aeration tank having a first contact portion formed with an inflow hole through which waste and wastewater abandoned at the bottom of the partition wall flows, and having a contact material for treating the introduced wastewater and wastewater by microorganisms;

In the upper portion is formed a through-hole through which the treated water treated by the first contact portion flows, and a second aeration portion having a diffuser formed therein to give up the treated water introduced through the through-hole, and the second aeration portion and the partition wall. A second aeration tank having a second contact portion separated by the barrier rib, and having an inflow hole through which the discarded treated water flows, and a contact material for treating the introduced treated water by microorganisms;

A sedimentation tank having a discharge pipe for retaining the treated water transferred through the treated water transport pipe connected to the second contact portion to settle the sludge and discharge the supernatant water to the outside; And

In the wastewater treatment apparatus using a microbial contact oxidation method comprising a sludge draw pipe for drawing the sludge precipitated in the sedimentation tank, the sludge storage tank for storing the concentrated sludge and transported to a separate sludge concentration tank, The sludge conveying pump 34 and the sludge conveying pipe 341 for conveying the sludge settled in the lower part to the 1st aeration part 21 are formed in the 2nd aeration tank 30, and the 1st aeration tank 20 is provided in the lower part. Provided is a sludge conveying pump 24 and a sludge conveying pipe 241 for transferring a part of the sludge settled to the sludge storage tank 50.

Hereinafter, the wastewater treatment apparatus using the microbial contact oxidation method according to the present invention will be described in more detail with reference to the accompanying drawings, but the accompanying drawings are only presented to help understanding of the present invention. It doesn't happen.

FIG. 2 is a schematic view of a wastewater treatment system according to an embodiment of the present invention, and FIG. 3 is an enlarged view of the aeration tank shown in FIG. 2, and the purification according to the present invention as shown in FIGS. The treatment apparatus includes: a flow regulating tank 10 for introducing wastewater and wastewater collected in a relay pumping station or a collecting well; The first aeration unit 21 for abandoning the wastewater and wastewater introduced from the flow rate adjustment tank 10 and the wastewater discarded in the first aeration unit 21 are treated by microorganisms fixed to the contact member 221. A first aeration tank (20) having a first contact portion (22); The second aeration portion 31 for abandoning the treated water treated by the first contact portion 22 and the waste water discarded in the second aeration portion 31 are formed by microorganisms fixed to the contact member 321. A second aeration tank (30) having a second contact portion (32) to process; A settling tank (40) for retaining the treated water treated in the second contact portion (32) to settle the sludge and discharge the supernatant water to the outside; And a sludge storage tank 50 which draws and stores the sludge precipitated in the settling tank 40.

First, although the flow control tank 10 is not shown in the drawing, the wastewater and wastewater collected in the normal relay pumping station or the sump are introduced through the wastewater and wastewater inflow pipe 11 to control the flow rate of the wastewater and the wastewater. Is installed. The waste water is preferably screened through a conventional screen (not shown) and then flows into the flow regulating tank 10.

The wastewater introduced into the flow rate adjustment tank 10 is transferred to the first aeration tank 20. In the first aeration tank 20 according to the present invention, the first aeration portion 21 and the first contact portion 22 are partition walls ( 23) separated form.

The first aeration part 21 is formed with a wastewater transport pipe 211 connected to the flow rate adjustment tank 10 at one upper end thereof, and an acid pipe 212 for discharging the introduced wastewater wastewater is formed at the lower portion thereof. do. When the wastewater is discarded by the first aeration unit 21, the activated sludge and the wastewater that are suspended in the first aeration unit 21 are mixed, and the wastewater is contained in the wastewater through this mixing process. Organic matter is decomposed and nitrification of nitrogen compounds occurs.

In addition, in the first contact portion 22, an inlet hole through which wastewater and waste water abandoned at the first aeration portion 21 may flow into a lower portion of the partition wall 23 formed to separate the first aeration portion 21 ( 231 is formed, and the contact material 221 for processing the inflowed wastewater by microorganisms is formed. The microorganism fixed to the contact member 221 removes organic matter and induces denitrification by using only dissolved oxygen present in the wastewater and wastewater abandoned by the first aeration unit 21.

In the present invention, the inlet hole 231 is formed in the lower portion of the partition wall 23 so that the waste water discarded in the first aeration part 21 may naturally flow into the first contact part 22. In addition, by dividing the first aeration tank into the first aeration portion and the first contact portion and giving up only at the first aeration portion and not giving up at the first contact portion 22, it is possible to prevent the desorption of microorganisms caused by conventional aeration. In addition to inducing denitrification to increase the nitrogen removal efficiency.

At this time, since the first contact portion 22 does not give up, natural precipitation of suspended solids, activated sludge, and floating microbial floc occurs at the lower portion thereof, and the precipitate accumulates at the bottom of the first aeration tank 20.

Therefore, it is preferable to further include a sludge feed pump 24 and a sludge feed pipe 241 for discharging a part of the accumulated sludge to the sludge storage tank 50 at the bottom of the first aeration tank 20.

The treated water treated by the first contact portion 22 is transferred to the second aeration tank 30. The second aeration tank 30 according to the present invention is similar to the first aeration tank 20 and the second aeration part 31 and The two contact portions 32 have a form separated by the partition wall 33.

At this time, the second aeration tank 30 induces the removal of organic substances and nitrogen remaining in the treated water treated in the first aeration tank 20 to maximize the treatment efficiency of nutrients contained in the waste water and waste water. It is formed for.

The second aeration part 31 is formed with a through hole 311 through which the treated water from the first contact portion 22 flows in an upper portion, and gives up the treated water introduced through the through hole 311 in a lower portion thereof. An diffuser 312 is formed. At this time, if the treated water introduced into the second aeration part 31 is abandoned, the activated sludge and the treated water suspended in the second aeration part 31 are mixed, and in this process, organic matter remaining in the treated water is decomposed. As a result, the nitrogen compounds are nitrified.

In addition, the second contact portion 32 has an inflow hole 331 through which the treated water abandoned in the second aeration portion 31 may flow into a lower portion of the partition 33 formed to separate the second aeration portion 31. The contact portion 321 is formed to treat the introduced treated water by the microorganism. The microorganism fixed to the contact material 321 removes the residual amount of organic matter remaining in the treated water by using only dissolved oxygen present in the wastewater and waste water discarded by the second aeration unit 31, and induces denitrification.

In this case, as the first contact portion 22 does not give up in the second contact portion 32, natural precipitation of suspended solids, activated sludge and floating microbial flocs occurs in the lower portion, and the precipitate is formed in the second aeration tank 30. ) Will be accumulated at the bottom.

Therefore, it is preferable to further include a sludge conveying pump 34 and a sludge conveying pipe 341 for conveying the accumulated sludge to the first aeration unit 21 at the lower end of the second aeration tank 30.

As the contact materials 221 and 321 formed in the first aeration tank 20 and the second aeration tank 30 can be applied to a variety of ordinary ones, but the present invention used a high HBC contact material.

The treated water treated by the second contact portion 32 is transferred to the settling tank 40 through the treated water transport pipe 41, and the settling tank 40 setstles the sludge by retaining the transferred treated water, and the symbol water is externally It has a discharge pipe 42 to discharge to.

In the present invention, in order to increase the removal efficiency of the phosphorus to form a central tube (43) for receiving the treated water in the settling tank 40, and the filtration layer 44 with a phosphorus adsorbent is built around the central tube (43). The treated water transferred to the central pipe 43 is pushed downward and passes through the filtration layer 44 in an upward flow. In this process, the sludge contained in the treated water is settled, and the phosphorus contained in the treated water Adsorption is removed in the course of passing through the filtration layer 44.

By doing in this way, not only the removal efficiency of phosphorus by a phosphate adsorbent can be improved, but also the filtration function by the filtration layer 44 becomes parallel, and it becomes possible to raise a purification process efficiency. The filtration layer 44 can be formed using a normal filtration layer.

In the present invention, the sludge scraper 45 for scraping the sludge precipitated on the bottom surface of the settling tank 40 to draw through the sludge drawing pipe 51 is installed, the central drive type sludge scraper generally used in the present invention. (45) was installed.

The scraper 45 can be easily installed by those skilled in the art to which the present invention pertains, so a detailed description of the structure and the operation relationship will be omitted.

The sludge precipitated in the settling tank 40 is transferred to the sludge storage tank 50, the sludge storage tank 50 is formed by the sludge draw pipe 51 for drawing the precipitated sludge, and concentrated by storing the drawn sludge After that it is transferred to a separate sludge concentration tank (not shown).

As described above, the wastewater treatment apparatus according to the present invention improves the wastewater treatment apparatus by the conventional catalytic oxidation method, and forms the aeration tank into the first aeration tank 20 and the second aeration tank 30 to form a wastewater treatment system. The removal efficiency of organic matters and nutrients such as nitrogen and phosphorus in waste water can be maximized.

In particular, each of the aeration tanks 20 and 30 is divided into aeration parts 21 and 31 and contact parts 22 and 32 to give up wastewater and wastewater only in the aeration parts 21 and 31, and at the contact parts 22 and 32, respectively. By not abandoning the wastewater and wastewater, it is possible to prevent the microbial detachment from the contact materials due to the conventional abandonment, and at the same time, the nitrification and denitrification process of the nitrogen compound can occur efficiently, thereby improving the wastewater treatment efficiency.

In addition, the aeration tanks 20 and 30 according to the present invention treat waste and wastewater using suspended growth microorganisms at the aeration units 21 and 31, and at the same time, waste and wastewater using microorganisms fixed at the contact portions 22 and 32. By making it possible to handle, it is easy to manage the microorganisms and to flexibly cope with the load fluctuations of the waste water.

In addition, the present invention improves the sedimentation tank (40) used in the conventional wastewater treatment system, the central tube (43) receiving the treated water, and the filtration layer (44) having a phosphorus adsorbent built around the central tube (43)) By including more it was possible to maximize the removal efficiency of phosphorus.

The wastewater treatment method using the wastewater treatment apparatus according to the present invention having the above configuration will be described in more detail.

4 is a view showing a waste water treatment process according to the present invention, the waste water treatment method according to the present invention with reference to Figures 2 and 3 as follows.

In the present invention, first, the waste water collected in the relay pumping station or the sump is passed through an inflow step S1 for transferring the flow control tank 10. At this time, in the process of transferring the waste water to the flow regulating tank 10, it is preferable to screen the waste water after screening using a screen (not shown in the drawing) in a conventional manner.

In this way, the wastewater and wastewater introduced into the flow regulating tank 10 are transferred to the first aeration part 21 of the first aeration tank 20. That is, the waste and wastewater of the flow rate adjustment tank 10 is transferred to the first aeration part 21 to give up and undergoes a first aeration step (S2) of oxidizing organic matter and nitrogen compounds.

In this first aeration step (S2), the waste water and waste water are mixed with activated sludge contained in the first aeration part 21, and organic matter contained in the waste water is decomposed by activated sludge, Nitrogen compounds are oxidized to nitrate via nitrite by nitrifying bacteria.

In this case, in order to maximize the load per unit volume, the first aeration unit 21 preferably maintains the concentration of activated sludge at about 2000 to 4000 mg / l, which is required by installing a conventional activated sludge measuring device SM. When the concentration of activated sludge is increased as described above, a part of the sludge is discharged to the sludge storage tank 50 by using the sludge transfer pump 24 and the sludge transfer pipe 241.

The primary aerated waste water is transferred to the first contact portion 22 separated by the partition 23 to induce removal and denitrification of organic substances contained in the waste water by microorganisms fixed to the contact material 221. Through the first processing step (S2).

In the first treatment step (S2), when the microorganism decomposes the organic material, the nitrate is changed to nitrogen gas while using the nitrate oxidized in the first aeration step (S1) instead of oxygen, thereby denitrification.

At this time, the present invention does not directly abandon the contact material 221 can not only prevent the desorption phenomenon of the microorganism by the conventional abandonment, it is possible to induce denitrification to increase the nitrogen removal efficiency.

The first treated water is passed to the second aeration part 31 to give up and undergoes a second aeration step (S4) of oxidizing organic substances and nitrogen compounds remaining in the treated water. In this step, the remaining amount of organic matter contained in the treated water is decomposed by the activated sludge contained in the second aeration part 31, and the remaining amount of nitrogen compound is nitrified.

The secondary aerated treated water is transferred to the second contact portion 32 separated by the partition 33 to induce removal and denitrification of residual organic matter contained in the treated water by microorganisms fixed to the contact material 321. It goes through the secondary processing step (S5). The microorganisms fixed to the contact material 321 in the secondary treatment step (S5) to remove the residual amount of organic matter remaining in the treated water using only dissolved oxygen present in the waste water abandoned in the second aeration unit 31, It will lead to denitrification.

At this time, the second contact portion 32 does not give up, the natural precipitation of the suspended solids and activated sludge and the floating microbial floc occurs in the lower portion, the precipitate is accumulated in the bottom of the second aeration tank (30). The sludge accumulated in this manner is conveyed to the first aeration part 21 using the sludge conveying pump 34 and the sludge conveying pipe 341.

The secondary treated water is transferred to the settling tank 40 and then settled to settle the sludge, discharge the symbol water to the outside, the discharged sludge is drawn out and transported to the sludge storage tank 50 (S6) Will go through.

According to the present invention, after the treated water is transferred to the central tube 43 in the process of retaining the treated water, the phosphate adsorbent is allowed to pass through the filter layer 44 in which the sorbent is embedded around the central tube 43 in the upward flow. The removal efficiency of phosphorus can be maximized.

At this time, the symbol water in the discharge step (S6) may be discharged to the river as it is through the discharge pipe 42, it may be discharged after a further treatment (chemical or physical treatment). In the process of installing the waste water and wastewater apparatus according to the present invention, it is appropriately installed according to the situation.

The settled sludge is transferred to the sludge storage tank 50 through the sludge drawing pipe 51, and the sludge transferred to the sludge storage tank 50 is concentrated and then transferred to a separate sludge concentration tank (not shown) for disposal. do.

In order to confirm the wastewater treatment efficiency of the wastewater treatment system using the microbial contact oxidation method according to the present invention, the wastewater treatment apparatus according to the conventional microbial contact oxidation method shown in FIG. 1 and the present invention shown in FIG. Treated with wastewater with BOD 200mg / ℓ, suspended solids (SS) 160mg / ℓ, total nitrogen (TN) 70mg / ℓ and total phosphorus (TP) 8mg / ℓ. The BOD, suspended solids, total nitrogen and total phosphorus concentration of the treated water were measured and the results are shown in Table 1 below.

division Conventional Wastewater Treatment System Wastewater treatment apparatus according to the present invention BOD (mg / ℓ) SS (mg / ℓ) T-N (mg / l) T-P (mg / ℓ) BOD (mg / ℓ) SS (mg / ℓ) T-N (mg / l) T-P (mg / ℓ) Influent 100.7 107.6 32.1 3.5 100.7 107.0 32.1 3.5 Treated water 15.0 15.0 15.0 2.0 6.8 6.0 7.8 1.0 Processing efficiency 85.1 86.0 51.9 42.9 93.2 94.4 75.0 71.4

As shown in Table 1, in the case of the wastewater treatment system according to the present invention, it can be seen that the treatment efficiency is greatly improved compared to the conventional wastewater treatment system, and in particular, the nitrogen and phosphorus removal efficiency is greatly improved. have.

As described above, the present invention is a useful invention that provides a wastewater treatment apparatus using microbial contact oxidation to improve the conventional catalytic oxidation method to maximize the removal efficiency of organic substances, nutrients such as phosphorus and nitrogen.

Claims (5)

delete A flow rate adjustment tank 10 in which a wastewater inflow pipe 11 for introducing wastewater and wastewater collected in a relay pumping station or a collecting well is formed; The first waste portion 21 is formed with a waste water transport pipe 211 connected to the flow rate adjustment tank 10 at an upper end thereof, and a diffuser 212 configured to abandon the introduced waste water by blowing air. The inlet hole 231 is separated by the first aeration part 21 and the partition wall 23, and the inflow hole 231 through which the waste water discarded is introduced is formed in the lower part of the partition wall 23. A first aeration tank (20) having a first contact portion (22) formed with a contact material (221) for processing by means of; A through hole 311 is formed in the upper portion through which the treated water flows from the first contact portion 22, and a diffuser 312 is formed in the lower portion to give up the treated water introduced through the through hole 311. The inlet hole 331 which is separated by the two aeration part 31, the said 2nd aeration part 31, and the partition 33, and in which the discarded process water flows is formed in the lower part of the partition 33, A second aeration tank (30) having a second contact portion (32) formed with a contact material (321) for treating the treated water by microorganisms; A settling tank (40) having a discharge pipe (42) for retaining the treated water transferred through the treated water transport pipe (41) connected to the second contact portion (32) to settle the sludge and discharge the supernatant water to the outside; And Sludge drawing pipe 51 for drawing the sludge precipitated in the settling tank 40 is formed, using the microbial contact oxidation method including a sludge storage tank 50 for storing the concentrated sludge and transporting it to a separate sludge concentration tank. In the wastewater treatment system, The second aeration tank 30 is formed with a sludge conveying pump 34 and a sludge conveying pipe 341 for conveying the sludge deposited in the lower portion to the first aeration unit 21, the first aeration tank 20 A sludge feed pump (24) and a sludge feed pipe (241) for transferring a portion of the sludge deposited in the sludge storage tank (50) are formed, the wastewater treatment apparatus by the microbial contact oxidation method. The method according to claim 2, wherein the sedimentation tank 40: the central tube 43 for receiving the treated water treated from the second contact portion 32 through the treated water transfer pipe 41 and the phosphate adsorbent around the central tube 43 Further comprising a built-in filtration layer 44, the wastewater treatment apparatus by the microbial contact oxidation method characterized in that the treated water transferred from the central tube (43) to pass through the filter layer 44 in an upward flow. The wastewater treatment apparatus according to claim 3, wherein the contact materials (221, 321) of the first contact portion (22) and the second contact portion (32) are HBC. delete