KR100465456B1 - A waste water treatment apparatus for removing nitrogen and phosphorus in the side stream and a waste water treatment method using the same - Google Patents

Abstract

The present invention, the primary sedimentation basin for performing the first precipitation reaction by introducing waste water; Aeration tank for performing the microbial treatment reaction by introducing the treated water after the first precipitation step; A secondary sedimentation basin performing a second precipitation reaction by introducing the treated water after the microbial treatment step; A sludge conveying line for conveying a part of the sludge generated in the secondary precipitation step to the aeration tank; In the waste water treatment apparatus comprising a concentration tank for carrying out the reaction to concentrate the sludge removed in the sludge return step, a digester for carrying out the digestion reaction and a dehydration tank for carrying out the dehydration reaction,

A primary return water conveying line for transferring the return water including the thickening vessel supernatant generated in the concentration step, the digester supernatant generated in the digestion step and the dehydration filtrate generated in the dehydration step to a countercurrent treatment aeration tank; A semi-water treatment aerobic tank for removing organic matter and phosphorus in the reflux water including the concentrated supernatant generated in the concentration step, the digester supernatant generated in the digestion step and the dehydration filtrate generated in the dehydration step, and nitrifying; A countercurrent treated oxygen-free tank for performing a denitrification reaction on the treated water passed through the countercurrent treated aerobic tank; And it relates to a wastewater treatment apparatus and a wastewater treatment method comprising the secondary return water return line for transferring the treated water passed through the reflux water treatment anaerobic tank to the primary sedimentation basin.

The wastewater treatment apparatus and method according to the present invention separates the conventionally used aeration tank into a partition without the need to add additional facilities and devices, and changes only the return water transfer line to be suitable for this. By transporting and treating, nitrogen and phosphorus in the return water can be effectively removed with minimal cost and facility change.

Description

A waste water treatment apparatus for removing nitrogen and phosphorus in the side stream and a waste water treatment method using the same}

The present invention relates to a wastewater treatment apparatus for effectively treating the return water generated in the sludge treatment process and a wastewater treatment method using the same, and more specifically, only a return water transfer line without a separate facility and apparatus for treatment of the return water. The present invention relates to a wastewater treatment apparatus and method that can effectively remove nitrogen and phosphorus in the effluent with a minimum cost and facility change by using an existing aeration tank.

In general, the wastewater treatment process adopts a method of inflowing wastewater into the sedimentation basin as shown in FIG. 1, precipitating it first, treating it with microorganisms in the aeration tank, and then again depositing and discharging it at the secondary sedimentation basin. Doing. The sludge produced at this time is called sludge, which is processed through condensation, anaerobic digestion, and dehydration process. The concentrate supernatant, digester supernatant, and dehydration filtrate generated during this sludge treatment are commonly referred to as side streams. .

Since the side stream generated in the wastewater treatment plant sludge treatment process is relatively small, but has a high concentration, it has been known to seriously affect the overall wastewater treatment efficiency because it causes an impact load on the water treatment system. The return water is a small flow rate of 1 to 3% of the total inflow, but it is known to increase 13 to 33% of the influent wastewater load, 5 to 47% of the nitrogen load, and 13 to 46% of the phosphorus load. Effluent from the sludge treatment system deteriorates the quality of the effluent if it causes an impact load on the wastewater treatment plant.

As can be seen in the prior art shown in Figure 1, in the prior art as a method for treatment of semi-water, the entire amount of semi-water generated in the sludge treatment process has been transferred to the settlement, and in this case, the transferred water Degradation of the efficiency of the settling basin resulted in an overload of organics, nitrogen and phosphorus in the aeration tank. In addition, when the rainwater bypasses the primary treated water, it causes many problems such as effluent discharged at a higher concentration than the influent raw water, which is more than nitrogen and phosphorus in the conventional wastewater treatment facility, which is mainly aimed at removing organic matter. It causes more problems in recent wastewater treatment plants whose main purpose is removal.

In order to solve this problem, Korean Laid-Open Patent Publication No. 2001-0011876 discloses a method and apparatus for removing nitrogen from the sewage treatment plant of the return water. As shown in FIG. 2, the method and apparatus are nitridized to a nitrogen concentration of the supernatant of the degreasing filtrate and the digester supernatant, which are generated during the return water treatment process, and then denitrification by using an organic material in the concentrate supernatant. Induced, treated treated water is characterized in that it is returned or returned to the sedimentation basin or primary sedimentation basin of the wastewater treatment plant depending on the water quality.

In addition, Korean Laid-Open Patent Publication No. 2002-0063502 discloses an 'improved sewage treatment method'. As shown in FIG. 3, the method returns the refluxed water to an anaerobic tank or an aerobic tank rather than the primary sedimentation basin, and adds a floating medium to the anaerobic tank to promote denitrification, and condensation is formed at the rear end of the aerobic tank. It is characterized by ensuring the setting time by installing a reaction vessel to play a role.

However, the prior art is not a device or method that utilizes the existing aeration tank as it is, and thus requires separate sewage dilution process or the installation of another advanced treatment facility, and thus requires the expansion and renovation of an existing wastewater treatment facility. There was a problem.

Therefore, the present invention separates the existing aeration tank into a bulkhead without separate facilities and devices such as a floating medium or a reaction tank serving as a condensation zone for treatment of the return water, and changes only the return water transfer line to return the water to the existing aeration tank. It is an object of the present invention to provide a wastewater treatment apparatus and a wastewater treatment method using the same, which can effectively remove nitrogen and phosphorus in the return water with minimal cost and facility change by transport.

1 is a block diagram of a semi-water treatment apparatus according to the prior art.

2 is a flow chart of a semi-emulsion treatment according to another prior art.

3 is a block diagram of an apparatus for treating semi-reflux water according to another prior art.

Figure 4 is a block diagram of an apparatus for treating the wake of the water according to an embodiment of the present invention.

<Brief description of the main parts of the drawing>

10: primary settler 12: aeration tank

14: secondary settling basin 15: sludge return line

16: concentration tank 18: digester

20: dehydration tank 21: primary return water return line

22: Effluent treatment aeration tank 24: Effluent treatment anaerobic tank

25: 2nd return water return line

In one embodiment of the present invention to achieve the above technical problem,

A primary sedimentation basin for introducing a wastewater to perform a first precipitation reaction; Aeration tank for performing the microbial treatment reaction by introducing the treated water after the first precipitation step; A secondary sedimentation basin performing a second precipitation reaction by introducing the treated water after the microbial treatment step; A sludge conveying line for conveying a part of the sludge generated in the secondary precipitation step to the aeration tank; In the waste water treatment apparatus comprising a concentration tank for carrying out the reaction to concentrate the sludge removed in the sludge return step, a digester for carrying out the digestion reaction and a dehydration tank for carrying out the dehydration reaction,

A primary return water conveying line for transferring the return water including the thickening vessel supernatant generated in the concentration step, the digester supernatant generated in the digestion step and the dehydration filtrate generated in the dehydration step to a countercurrent treatment aeration tank; A semi-water treatment aerobic tank for removing organic matter and phosphorus in the reflux water including the concentrated supernatant generated in the concentration step, the digester supernatant generated in the digestion step and the dehydration filtrate generated in the dehydration step, and nitrifying; A countercurrent treated oxygen-free tank for performing a denitrification reaction on the treated water passed through the countercurrent treated aerobic tank; And it provides a wastewater treatment apparatus comprising a secondary return water conveying line for transferring the treated water passed through the reflux water treatment anaerobic tank to the primary sedimentation basin.

It is preferable that the aeration tank, the return water treatment aerobic tank, and the return water treatment anaerobic tank exist in a single reaction tank separated by a partition wall.

In addition, in another embodiment of the present invention to achieve the above technical problem,

Introducing the wastewater and precipitating at the primary settling basin; Introducing microbial treatment in an aeration tank by introducing the treated water having undergone the first precipitation step; Precipitating the treated water that has undergone the microbial treatment in a secondary settler; Conveying a portion of the sludge generated in the secondary precipitation step to the aeration tank; And in the wastewater treatment method consisting of the step of concentrating, digesting and dehydrating the sludge excluded from the sludge conveying step,

Returning the reflux water including the thickening vessel supernatant generated in the concentration step, the digester supernatant generated in the digestion step and the dehydration filtrate generated in the dehydration step to a countercurrent treatment aeration tank to remove organic matter and phosphorus, and nitrifying; Performing a denitrification reaction on the treated water that has passed through the countercurrent treated aerobic tank in a countercurrent treated anoxic tank; Transferring the treated water that has undergone the reflux treatment anoxic tank to the primary sedimentation basin and mixing it with the incoming wastewater; And it provides a wastewater treatment method comprising performing the first precipitation step, the microbial treatment step and the second precipitation step for the reflux water mixed with the inflow wastewater.

Except for the concentrate supernatant generated in the concentration step in the reflux water, it is preferable that only the digester supernatant generated in the digestion step and the dehydration filtrate generated in the dehydration step are returned to the countercurrent treated aerobic tank for treatment.

Hereinafter, a wastewater treatment apparatus and a wastewater treatment method using the same according to the present invention will be described in detail with reference to the drawings.

Wastewater treatment apparatus according to the present invention, the primary sedimentation basin (10) performing the first precipitation step, the aeration tank (12) performing the microbial treatment step, the secondary sedimentation basin (14) performing the second precipitation step, sludge conveyance A wastewater treatment apparatus comprising a thickening tank (16), a digestion tank (18), and a dewatering tank (20) for treating sludge removed from the line 15 and sludge conveying step, wherein the return water generated in the sludge treatment step is effected. The present invention relates to a wastewater treatment apparatus and method for treating economically and economically.

The effluent including the thickening tank 16 supernatant, the digester 18 supernatant and the dehydration filtrate generated in the dehydration tank 20 generated in the sludge treatment step is a semi-reflux treatment aerobic tank by the primary backwater return line 21. Returned to (22). The refluxed water returned as described above is freed of organic matter and phosphorus by the aerobic microorganisms in the countercurrent treated aerobic tank 22, and nitrification is carried out.

The nitrified water which has been nitrified in the semi-water treatment aerobic tank 22 is transferred to the semi-water treatment anaerobic tank 24, and the denitrification reaction is carried out using denitrification bacteria or the like in the semi-water treatment anaerobic tank 24.

The aeration tank 12, the semi-water treatment aerobic tank 22, and the semi-water treatment anaerobic tank 24 according to the present invention may be formed by simply separating the aeration tank or the microbial treatment reaction tank including the conventional anoxic tank and the aerobic tank into partitions.

Next, the treated water which has passed through the semi-reflux treatment anaerobic tank 24 is transferred to the primary sedimentation basin 10 by the second semi-reflux return line 25, and the treated return water transferred to the primary sedimentation basin 10 is here. Is mixed with influent wastewater from If the return water is returned to an anaerobic or aerobic tank in the existing aeration tank, there is a problem because the efficiency of wastewater treatment decreases due to the high concentration of return water. Since no facility is required, it is preferable to transfer the treated water which has undergone the counter-water treatment anaerobic tank to the primary sedimentation basin.

The treated return water mixed with the influent wastewater is then discharged to the outside after the same process as the influent wastewater, that is, the first precipitation step, the microbial treatment step and the second precipitation step.

The reflux water subject to the treatment of the method according to the present invention is the digester (18) supernatant except the supernatant (16) supernatant from the concentrate tank (16) supernatant, digester (18) supernatant and dehydration filtrate from the dehydration tank (20). And dehydration filtrate. The concentrate (16) supernatant has a relatively low nitrogen concentration and a high SCOD / NH ₄ ⁺ -N ratio compared to the digester (18) supernatant and dehydration filtrate, thus concentrating the (16) supernatant with the digester (18) supernatant and dehydration filtrate. In the case of treatment, it is difficult to achieve more efficient return water treatment efficiency due to the increased treatment flow rate.

Hereinafter, the present invention will be described in more detail with reference to Examples. The following examples are provided to illustrate the present invention, but the scope of the present invention is not limited to the following examples.

Example 1 Manufacture of Wastewater Treatment System According to the Present Invention

As described above, the aeration tank commonly used in the conventional wastewater treatment apparatus is separated by a bulkhead into an aeration tank, a return water treatment aeration tank and a return water treatment anoxic tank, and connects the concentration tank, the digestion tank and the dehydration tank and the return water treatment aeration tank. A wastewater treatment apparatus according to the present invention was manufactured by providing a secondary wakewater return line and a secondary wakewater return line connecting an anoxic tank and a primary sedimentation basin.

Example 2 Performance Test of Wastewater Treatment System According to the Present Invention

Using the wastewater treatment device according to the present invention, the treated wastewater generated in Gyeongbuk N sewage treatment plant was treated, and the installation of the wastewater treatment device was completed in December 2001 in order to examine the characteristics of the treated water in the winter temperature drop. It started driving at the end of January, and stopped at the end of May 2002. The operating temperature was set at a minimum of 13 ° C. to a maximum of 20 ° C., and the generated return water was totally treated, and the flow rate at this time was at most 816 m ³ / day to at least 384 m ³ / day. Therefore, the hydraulic retention time (HRT) was operated on average 2.4 days.

Table 1 below shows the treatment efficiency of each component in the refluxed water when treating the refluxed water using the apparatus according to the present invention.

ingredient Effluent raw water (mg / ml) Effluent treated water (mg / L) Removal efficiency (%) TCOD 3,100 105 95.7 SCOD 700 56 91.6 BOD 134 8 93.9 NH ₄ ⁺ -N 99 15 81.3 TN 100 27.3 68.5 T-P 82.8 9.4 84.1 S-P 26.1 3.9 80.7

TCOD: Total Chemical Oxygen Demand

SCOD: Soluble Chemical Oxygen Demand

BOD: Biochemical Oxygen Demand

NH ₄ ⁺ -N: Ammonium Nitrogen

TN: Total Nitrogen

TP: Total Phosphate

SP: Soluble Phosphate

Comparative Example 1. Performance Test of Wastewater Treatment System According to the Prior Art

Experiments were carried out under the same conditions as in Example 2, using a wastewater treatment apparatus according to the prior art that does not undergo a separate reflux treatment process.

Table 2 below shows the wastewater treatment results according to Example 2 and Comparative Example 1 by comparing each component in the influent wastewater.

ingredient Example 2 Comparative Example 1 Increased throughput (%) Influent (mg / L) Effluent (mg / L) Processing efficiency (%) Influent (mg / L) Effluent (mg / L) Processing efficiency (%) BOD 194 15.6 91.7 279 17.5 92.9 1.2 COD 137 18.4 85.0 216 16.8 90.3 5.2 SS 255 10.3 95.7 395 12.1 96.1 0.4 T-N 37.2 20.4 43.7 49.6 10.7 78.5 34.8 T-P 5.7 2.0 63.7 7.9 1.6 79.4 15.7

As can be seen from the results of Table 1 and Table 2, the wastewater treatment apparatus according to the present invention is effective in minimizing the effect of the return water on the existing aeration tank, and particularly in the treatment of components such as nitrogen and phosphorus. It was found to be very effective.

The wastewater treatment apparatus and method according to the present invention separates the conventionally used aeration tank into a partition without the need to add additional facilities and devices, and changes only the return water transfer line to be suitable for this. By transporting and treating, nitrogen and phosphorus in the return water can be effectively removed with minimal cost and facility change.

Claims (4)

A primary sedimentation basin for introducing a wastewater to perform a first precipitation reaction; Aeration tank for performing the microbial treatment reaction by introducing the treated water after the first precipitation step; A secondary sedimentation basin performing a second precipitation reaction by introducing the treated water after the microbial treatment step; A sludge conveying line for conveying a part of the sludge generated in the secondary precipitation step to the aeration tank; In the waste water treatment apparatus comprising a concentration tank for carrying out the reaction to concentrate the sludge removed in the sludge return step, a digester for carrying out the digestion reaction and a dehydration tank for carrying out the dehydration reaction, A primary return water conveying line for transferring the return water including the thickening vessel supernatant generated in the concentration step, the digester supernatant generated in the digestion step and the dehydration filtrate generated in the dehydration step to a countercurrent treatment aeration tank; A semi-water treatment aerobic tank for removing organic matter and phosphorus in the reflux water including the concentrated supernatant generated in the concentration step, the digester supernatant generated in the digestion step and the dehydration filtrate generated in the dehydration step, and nitrifying; A countercurrent treated oxygen-free tank for performing a denitrification reaction on the treated water passed through the countercurrent treated aerobic tank; And And a secondary return water conveying line for transferring the treated water that has undergone the treatment of anaerobic treatment to the primary sedimentation basin. The wastewater treatment apparatus according to claim 1, wherein the aeration tank, the return water treatment aerobic tank, and the return water treatment anaerobic tank are separated by a partition wall in one reactor. Introducing the wastewater and precipitating at the primary settling basin; Introducing microbial treatment in an aeration tank by introducing the treated water having undergone the first precipitation step; Precipitating the treated water that has undergone the microbial treatment in a secondary settler; Conveying a portion of the sludge generated in the secondary precipitation step to the aeration tank; And in the wastewater treatment method consisting of the step of concentrating, digesting and dehydrating the sludge excluded from the sludge conveying step, Returning the reflux water including the thickening vessel supernatant generated in the concentration step, the digester supernatant generated in the digestion step and the dehydration filtrate generated in the dehydration step to a countercurrent treatment aeration tank to remove organic matter and phosphorus, and nitrifying; Performing a denitrification reaction on the treated water that has passed through the countercurrent treated aerobic tank in a countercurrent treated anoxic tank; Transferring the treated water that has undergone the reflux treatment anoxic tank to the primary sedimentation basin and mixing it with the incoming wastewater; And Wastewater treatment method comprising performing the first precipitation step, the microbial treatment step and the second precipitation step for the reflux water mixed with the inflow wastewater. [5] The method according to claim 4, wherein, except for the supernatant solution generated in the concentration step of the reflux water, only the digester supernatant generated in the digestion step and the dehydration filtrate generated in the dehydration step are returned to the countercurrent treatment aerobic tank for treatment. Wastewater treatment method.