KR100783789B1 - Apparatus for wastewater treatment and method for wastewater treatment using the same - Google Patents

Abstract

A wastewater treatment apparatus comprising a denitrifying reactor and a denitrifying filtration tank and a wastewater treatment method using the wastewater treatment apparatus are provided to secure a stable quality of the effluent by reducing a nitrogen content of final effluent during wastewater treatment, thereby preventing nitrogen contained in the effluent from having a bad influence on an ecological environment of a water system. A wastewater treatment apparatus comprises: a first sedimentation tank(10) into which wastewater is flown, and in which a settling process of wastewater is performed; a bioreactor including an aerobic tank(40) for nitrifying effluent of the first sedimentation tank using microorganisms; a second sedimentation tank(50) for settling a microorganism sludge of the bioreactor; a denitrifying reactor(60) which contains effluent of the second sedimentation tank, and in which carriers are embedded to denitrify the effluent; and a denitrifying filtration tank(70) in which a filter medium is contained to remove suspended solids contained in effluent of the denitrifying reactor, and which removes residual nitrates of the effluent. The carriers are waste tire-processed fluidized bed carriers or polyurethane carriers. The filter medium has a filtration ratio of 50 to 100 m^3/m^2.d. The bioreactor additionally includes an anaerobic tank(20) and an anoxic tank(30).

Description

Sewage treatment apparatus and sewage treatment method using the same {APPARATUS FOR WASTEWATER TREATMENT AND METHOD FOR WASTEWATER TREATMENT USING THE SAME}

1 is a conceptual diagram showing a sewage treatment apparatus of the present invention.

Figure 2a is NO ₃ according to the filtration rate Graph showing removal rate.

Figure 2b is a graph showing the removal rate of suspended matter according to the filtration rate.

3 is a graph showing the NO ₃ removal rate according to the external carbon source injection amount.

Figure 4 is a graph showing the NO ₃ removal rate with temperature.

5 is a graph showing the change in NO ₃ removal rate by operating the sewage treatment method of the present invention for a long time.

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

10: primary sedimentation tank 20: anaerobic tank

30: anoxic tank 40: aerobic tank

50: secondary precipitation tank 60: denitrification reactor

70: denitrification tank

The present invention relates to a sewage treatment apparatus and a sewage treatment method using the same, and more particularly, to improve the denitrification efficiency of a sewage treatment process, to contain nitrogen in the effluent to prevent damaging the environment of the water system and using the same. It relates to a sewage treatment method.

In general, the sewage treatment is a method of sedimentation and discharge from the secondary sedimentation basin after the influent sewage is treated with microorganisms in the microbial reaction tank consisting of anaerobic tank, anoxic tank, and aerobic tank after the first settling.

At this time, the microorganisms produced in the microbial reaction tank is called sludge, which is precipitated in the secondary settling tank. Precipitated sludge is circulated to some microbial reactors, and some is discharged to waste sludge treatment.

On the other hand, the effluent discharged to the water system in such a sewage treatment stream has a problem that acts as a factor that inhibits the ecological environment of the water system because the nitrogen concentration is higher than the flow rate.

In other words, the Sewage Terminal Treatment Facility Analysis Report (2005, Ministry of Environment) shows that the average concentrations of T-N (total nitrogen) of influent and effluent in general sewage treatment plants were 32.1; At 16.3 mg / L, the removal rate was only about 49%, and in some sewage treatment plants, the annual average discharge quality of T-N exceeded the water quality standard.

On the other hand, the average TN effluent quality of 152 sewage treatment plants operated as advanced treatment facilities is 13.0mg / L, far exceeding the recommended 10mg / L recycled water quality standard. This means that the effluent from the sewage treatment plant operated as an advanced treatment facility is not suitable for being discharged into the water system for river maintenance. Therefore, there is a need for additional nitrogen removal, and since most of the TN in the sewage treatment plant effluent is present in the form of nitrate (NO ₃ ), a post-denitrification process that can additionally remove such nitrate is urgently needed.

The present invention has been made to improve the above-mentioned problems, sewage treatment apparatus that can ensure a stable effluent quality by reducing the nitrogen content of the final effluent during sewage treatment to prevent adverse effects on the ecological environment of the water system and The purpose is to provide a sewage treatment method using the same.

As a means for achieving the above object, the sewage treatment apparatus of the present invention, a microbial reaction tank including a primary sedimentation tank for introducing sewage into the sewage, and an aerobic tank for nitrifying the effluent of the primary sedimentation tank using microorganisms, The secondary sedimentation tank for precipitating the microbial sludge of the microbial reaction tank, and the effluent of the secondary sedimentation tank is accommodated, the denitrification tank for denitrification through the carrier therein and the suspended substances contained in the effluent of the denitrification tank are removed through the internal media. And a denitrification filtration tank for removing residual nitrate from the effluent.

In addition, the sewage treatment method of the present invention, a microbial reaction process comprising a first precipitation step of introducing sewage by introducing sewage, and a step of nitrifying the effluent of the first precipitation step under aerobic conditions using a microorganism, and the microorganism The secondary precipitation step of precipitating the microbial sludge of the reaction process, and the effluent water of the secondary precipitation step is accommodated, the denitrification step of denitrification process by introducing an external carbon source to the effluent and denitrification through an internal carrier and included in the effluent of the denitrification process It is characterized in that it comprises a denitrification filtration process to remove the suspended matter, and to remove the residual nitrate of the effluent.

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

1 is a conceptual diagram showing a sewage treatment apparatus of the present invention.

As shown in Figure 1, the sewage treatment apparatus of the present invention, the first settling tank 10 for introducing the sewage into the sediment, and the microbial reaction tank for treating the effluent of the first settling tank 10 by using microorganisms, It consists of a secondary settling tank (50) for precipitating the effluent of the microbial reaction tank, a denitrification reactor (60) for denitrification, and a denitrification filtration tank (70) for removing suspended matters through the internal media.

The microbial reaction tank, nitrogen (N), phosphorus (P) and organic by introducing the treated water passing through the first settling tank 10 to the microbial reaction tank consisting of anaerobic tank 20, anoxic tank 30 and aerobic tank 40 Remove the material. That is, after the first precipitation process to release phosphorus (P) in the anaerobic tank and denitrate the nitrate (NO ₃ ) in the internal transport water returned from the aerobic tank 40 in the anoxic tank 30, the organic matter oxidation in the aerobic tank 40, The microorganisms are processed in the order of nitrification and phosphorus accumulation.

On the other hand, the microbial reaction tank may be composed of a single aerobic tank 40 as well as biological nitrogen, phosphorus removal process consisting of anaerobic tank 20, anoxic tank 30 and aerobic tank 40, as well as standard activated sludge process. That is, the present invention can be equally applied to a process including the aeration tank 40, such as a conventional biological nitrogen, phosphorus removal process, as well as a standard activated sludge process, will be described below with reference to the former.

The denitrification reaction tank 60 is filled with a carrier in a volume ratio of 10% to prevent the microorganisms from floating out by being attached to the carrier, thereby controlling the concentration of the microorganisms in the denitrification reaction tank 60. At this time, the denitrification tank 60 is preferably provided with a stirrer to promote the suspension of the carrier. In addition, the carrier may be applied to the fluidized bed carrier processed sponge or waste tire of polyurethane.

The denitrification tank 60 removes the suspended matter contained in the effluent through a sand layer (media) made of a predetermined height therein and finally discharges it.

 Hereinafter, a sewage treatment method using the sewage treatment apparatus having the above configuration will be described.

The sewage treatment method of the present invention comprises a first precipitation step → a microbial reaction step → a second precipitation step → a denitrification step → a denitrification filtration step.

1) In the first precipitation process, sewage from the sewage treatment plant is introduced into the primary sedimentation tank 10 to precipitate suspended solids in the sewage, and then the treated water is discharged into the microbial reaction process.

2) The microbial reaction process flows the treated water passing through the primary settling tank 10 into the microbial reaction tank consisting of the anaerobic tank 20, the anoxic tank 30 and the aerobic tank 40, nitrogen (N), phosphorus (P) and Remove organic matter. That is, after the first precipitation process, the phosphorus (P) is released from the anaerobic tank 20, the nitrate (NO ₃ ) is denitrated in the anoxic tank 30, and the organic matter is oxidized, nitrified, and phosphorus (P) accumulates in the aerobic tank 40. Process in order.

3) In the secondary precipitation step, the microorganisms produced in the microbial reaction step are precipitated and removed in the secondary settling tank 50, and at this time, a part of the precipitated microorganisms (sludge) is returned to the anaerobic tank 20 during the microbial reaction step. And the remaining sludge is treated as waste sludge.

4) In the denitrification process, carbon is supplied to the microorganisms contained in the denitrification tank 60 by inputting an external carbon source into the denitrification tank 60 in which the outflow water of the secondary precipitation tank 50 is accommodated.

On the other hand, the denitrification reaction tank 60 is filled with a carrier to prevent the microorganisms from floating and detached by attaching the microorganisms to the carrier to control the concentration of the microorganisms in the denitrification reaction tank 60.

That is, the microorganism is to perform the role of denitrification bacteria to denitrate nitrates, and to activate the denitrification reaction by supplying a carbon source by injecting an external carbon source to the denitrification bacteria.

5) The denitrification filtration process removes the suspended matter contained in the effluent of the denitrification tank 60 through the media of the denitrification filtration tank 70 and finally discharges it. At this time, in the denitrification filtration process, an external carbon source input from the denitrification tank 60 is left to supply additional carbon denitrification to the microorganisms in the denitrification filtration tank 70. Therefore, in the denitrification filtration process, not only the removal of suspended solids but also secondary denitrification takes place.

Looking at the operation of the sewage treatment method of the present invention having such a process as follows.

Figure 2a is NO ₃ according to the filtration rate And it is a graph showing the removal of suspended matter, Figure 2b is a graph showing the removal of suspended matter according to the filtration rate.

As shown in Figures 2a and 2b, the filtration rate for the filter medium of the denitrification tank 70 was changed from 50 m ³ / m ² · d to 150 m ³ / m ² · d, both nitrogen removal rate and suspended solids removal rate was significantly affected .

That is, when the filtration rate was 50-100m ³ / m ² ㆍ d, the removal rate of the suspended solids was almost unchanged from 81.6% to 79.4%, but decreased to 52.4% at 150m ³ / m ² ㆍ d. On the other hand, the NO ₃ removal rate was 68.1% at a filtration rate of 100m ³ / m ² ㆍ d, but decreased to 50.4% at 150m ³ / m ² ㆍ d. Therefore, it can be seen that the proper filtration rate of the denitrification filtration tank 70 is preferably 50 to 100 m ³ / m ² · d.

3 is a graph showing the NO ₃ removal rate according to the external carbon source injection amount.

The input amount of the external carbon source for the denitrification of the nitrified effluent in the aerobic tank 40 was 0%, 50% and 100% of the metalol of the theoretical amount (theoretical carbon source requirement), and as shown in FIG. When 100% of methanol is added, the denitrification rate is 70.2%, which is the most efficient. In this case, the theoretical amount may be calculated based on an empirical equation (McCarty et al., 1969).

Cm = 2.47 N ₀ + 1.53 N ₁ + 0.87 D ₀

Where Cm = Methanol requirement (mg / L), N ₀ = NO ₃ ^-- N (mg / L), N ₁ = NO ₂ ^-- N (mg / L), D ₀ = DO (mg / L).

That is, 0%, 50%, and 100% are input by assuming that the value calculated by Equation 1 is 100% of the theoretical carbon source requirement.

4 is a graph showing the NO ₃ removal rate with temperature.

As shown in FIG. 4, when the reaction temperature of the denitrification tank 60 and the denitrification tank 70 was changed from 18 ° C. to 30 ° C., the NO ₃ removal rate was stably maintained between 65.7% and 70.5%. It can be seen that it does not affect.

5 is a graph showing the change in the NO ₃ removal rate by operating the sewage treatment method of the present invention for a long time, Table 1 shows the operating conditions during long-term operation.

As shown in Table 1, in the long-term operation under the above-described conditions, the normal operating conditions (Mode 6, 6), except that the filtration rate is too high (Mode 3) and the external carbon source is injected less than the required amount (Mode 4, 5) 7, 8, and 9) show a high denitrification rate of about 70% (as shown in FIG. 5). That is, the filtration rate is 50 to 100 m ³ / m ² ㆍ d and the amount of external carbon source is 100%. It can be seen that Mode 6 to Mode 9 operated show the most efficient NO ₃ removal rate, which is the most efficient operation condition.

The present invention described above is not limited to the above-described embodiment and the accompanying drawings, and it is common in the art that various substitutions, modifications, and changes can be made without departing from the technical spirit of the present invention. It will be evident to those who have knowledge of.

As described above, the sewage treatment apparatus of the present invention and the sewage treatment method using the same, the denitrification reaction tank denitrification through the external carbon source and the carrier during the sewage treatment, removing the suspended matter in the denitrification filtration tank and additional denitrification is made of the final effluent By reducing the total nitrogen concentration it is possible to prevent adverse effects on the ecological environment of the water system.

Claims (5)

A primary sedimentation tank for introducing sewage into the sewage; A microbial reaction tank including an aerobic tank for nitrifying the effluent of the primary precipitation tank using microorganisms; A secondary sedimentation tank for precipitating the microbial sludge of the microbial reaction tank; A denitrification tank containing the effluent water of the secondary precipitation tank and denitrifying through a carrier therein; And Sewage treatment apparatus comprising a denitrification filtration tank to remove the suspended matter contained in the effluent of the denitrification tank through the internal filter medium, and to remove the residual nitrate of the effluent. The method of claim 1, The carrier, Sewage treatment apparatus, characterized in that the waste tire is processed fluidized bed carrier or polyurethane carrier. The method of claim 1, The filtration rate of the filter medium is a sewage treatment apparatus, characterized in that 50 ~ 100m ³ / m ² ㆍ d. A primary precipitation step of introducing sewage into the sewage; A microbial reaction process comprising nitrifying the effluent of the primary precipitation process under aerobic conditions using microorganisms; A secondary precipitation step of precipitating the microbial sludge of the microbial reaction process; A denitrification process in which the effluent water of the secondary precipitation process is accommodated, and an external carbon source is introduced into the effluent and denitrified through an internal carrier; And And a denitrification filtration step of removing suspended solids contained in the effluent of the denitrification step and removing residual nitrate of the effluent. The method of claim 4, wherein The external carbon source is a metalol, 100% compared to the theoretical amount, The theoretical amount is sewage treatment method characterized in that it is calculated by the following equation: Cm = 2.47 N ₀ + 1.53 N ₁ + 0.87 D ₀ {Where Cm = metalol demand (mg / L), N ₀ = NO ₃ ^-- N (mg / L), N ₁ = NO ₂ ^-- N (mg / L), D ₀ = DO (mg / L )}

Images