KR20210145706A - System for Advanced Treatment of Sewage and Wastewater - Google Patents

Abstract

The present invention relates to a unit process for advanced removal of nitrogen and phosphorus, and specifically, to a unit process for advanced water treatment of wastewater, which meets nitrogen and phosphorus concentration of finally discharged water by adding a device of a simple structure while maintaining the basic design concept of a conventionally installed water treatment facility and can be reused. More specifically, the present invention relates to a system for removing residual nitrogen and phosphorus by using treated water of physically/biologically treated wastewater as influent water.

Description

System for Advanced Treatment of Sewage and Wastewater

The present invention relates to a unit process for highly removing nitrogen and phosphorus, and more particularly, by adding a device of a simple structure while maintaining the basic design concept of a conventionally installed water treatment facility, the nitrogen and phosphorus concentration of the final discharge water is enhanced. It relates to a unit process for advanced water treatment of wastewater that meets the standards of effluent quality and can be reused.

Nationally, to improve the quality of effluent discharged from sewage treatment plants, the permissible discharge standards are gradually being strengthened. From 2019, the standards for effluent from public sewage treatment facilities have reached TN 20 mg/L and TP 0.2 mg/L. have.

Nitrogen removal is accomplished through a nitrification process that converts nitrogen compounds in wastewater into nitrate nitrogen in an aerobic state and a denitrification process that reduces nitrate nitrogen into nitrogen gas in an anaerobic atmosphere. Phosphorus is released by the metabolic activity of microorganisms, and the microorganisms ingest excessive phosphorus in an aerobic state and then remove it as sludge.

However, in particular, the problem of low nitrogen treatment efficiency in sewage treatment plants due to the low water temperature in winter is that the microorganisms involved in the conversion of ammonia to nitrate nitrogen are autotrophic microorganisms that _{grow inorganic substances such as CO 2} as a carbon source. It is affected by growth, so it is difficult to remove nitrogen, and most of the sludge with a very high phosphorus content is returned to the flow control tank and the bioreactor tank. When this concentration is gradually increased, there is a limit in that the discharge concentration gradually increases.

Most of the existing wastewater treatment plants that treat sewage and sewage are designed and operated by the activated sludge method. . Therefore, various modified treatment processes such as A/O, A2/O, Berdenoho method, Postrip method, and batch activated sludge method (SBR) are known to remove nitrogen and phosphorus from wastewater. However, the A/O method and the A2/O method each have problems in that the removal efficiency of ammonia nitrogen in wastewater is low and the land requirement is large, and the batch activated sludge method has the advantage that nitrogen and phosphorus can be removed in one reactor However, there is a disadvantage in that it is very sensitive to the additional installation of the storage tank and the load because the operation is not performed continuously.

Furthermore, in these modified processes, one to four reactors must be added to the existing activated sludge method wastewater treatment facility for the simultaneous removal of biological nitrogen and phosphorus. It is difficult to obtain land.

However, even if various water treatment processes are applied, Korea does not have enough land area, unlike other countries where sufficient residence time is guaranteed due to the large site area. Therefore, it is not easy to meet the strengthened effluent water quality standards because the biological water treatment process is operated with a short hydraulic residence time (HRT, usually within 6 hours). In addition, since the existing sewage treatment facilities were designed according to relatively relaxed water quality standards, the reality is that it is difficult to meet the new effluent water quality standards at the level of improvement in the operation method. Accordingly, there is a need to continuously expand the new advanced sewage treatment facility, but it is not easy because there is a burden of site and construction costs, and remodeling of an existing facility that is optimized according to the situation is not only expensive, but also has the possibility of causing a change in the system. Therefore, technology that enables advanced water treatment and reuse without changing the basic design of existing water treatment facilities is required.

In order to remove nitrogen and phosphorus in treated water from which organic matter has been removed by conventional various biological water treatment facilities (in the past, when the effluent water quality standard was high, it was discharged as it is), various attempts to simultaneously treat it with a physical, chemical or biological unit process is being done

For example, there is a technique using chemical treatment and tertiary precipitation or filtration by administering a coagulant (mainly ALUM or PAC) to treated water that has undergone biological advanced treatment. However, according to this, although the phosphorus removal effect is sufficient, there are difficulties such as the use of a large amount of chemicals and clogging of the pores of the filter.

In addition, biologically advanced wastewater treatment methods include flow path change method (HDF), B3 (Bio Best Bacillus) method, KIDEA method, treatment method using soil microorganisms (HBR), anoxic/anaerobic/aerobic/deaeration tank and submerged hollow fiber membrane The used treatment method (HANT), the treatment method using the ultrafiltration hollow fiber membrane (MBR), etc. are known. However, these methods are treatment methods using suspended-growing microorganisms, and the nitrification rate is lowered at low water temperatures in winter, making it difficult to stably remove total nitrogen. There are difficulties in efficient processing. In addition, due to the qualitative and quantitative characteristics of domestic wastewater that the concentration of organic carbon source is low and the change in pollutant load by season is large, its performance is often not fully exhibited.

Registered patent 10-1758049 (floating and continuous filtration combined water treatment device that simultaneously removes nitrogen and phosphorus) uses a chemical method to simultaneously remove nitrogen and phosphorus, and registered patent 10-1879740 (advanced wastewater treatment device) uses an anaerobic tank. A water treatment device that can increase the effect of treating organic matter, nitrogen, and phosphorus in wastewater by repeatedly installing an anoxic tank and an aerobic tank at the rear end is presented. However, these prior arts require a 'new facility', and there is no concept of utilizing the facilities and space of a conventionally installed water treatment facility.

Registered Patent 10-1884448 (Advanced water treatment device for wastewater using ozone) is a wastewater treatment system that can improve the quality of the treated water finally discharged by treating various organic and inorganic pollutants that are difficult to treat only with the bioreaction process with ozone. It relates to an advanced water treatment system. However, according to this, it is necessary to install a membrane separation tank instead of a final sedimentation tank in a conventional water treatment facility, and an 'ozone contact means' having a complicated structure for ozone treatment of the effluent is required.

Registered Patent 10-1167488 (System for Simultaneous Removal of Phosphorus and Nitrogen in Sewage Wastewater) describes a method that can simultaneously remove phosphorus and nitrogen by a physicochemical treatment method using physical primary treatment and biological secondary treatment wastewater as influent water. An air-floating reactor system using oxide-coated sand media is disclosed. However, this structure is difficult to withdraw oxide or denitrification microorganisms sufficiently coated or absorbed on a sand filter material by using a small air gap sand filter media, especially the nitrate nitrogen remaining in the influent (NO ₃ ^-) only to process only ammonia nitrogen to be removed it is impossible Denitrification microorganisms are heterotrophic microorganisms that have high growth rates even at low water temperature and perform denitrification well. However, when nitrification is not performed in the activated sludge process, ammonia flows in at a high concentration and nitrification mechanism does not occur, so total nitrogen removal is not performed effectively. In addition, according to this, since there is no buffer function for phosphorus removal, if the phosphorus concentration of the influent changes abruptly, there is a fear that a significant concentration of phosphorus is released without being removed.

Registered Patent 10-1758049 Registered Patent 10-1879740 Registered Patent 10-1884448 Registered Patent 10-1167488

An object of the present invention is to provide a system for improving the total nitrogen and total phosphorus treatment efficiency of the existing water treatment facility.

In addition, the present invention stably satisfies the reinforced effluent water quality standard even under shock loads such as low water temperature in winter and inflow of toxic substances by reducing the nitrogen and phosphorus concentrations of the final discharged water without changing the basic design of the existing water treatment facility, and further An object of the present invention is to provide a system for advanced water treatment to the extent that treated water can be reused.

The present invention for achieving the above object

A system for removing residual nitrogen and phosphorus by using treated water physically/biologically treated as wastewater as influent,

(A) a body in which the media layer made of zeolite particles and the following components are accommodated in whole or in part; an inflow distribution pipe installed at the lower part of the main body so that the influent water is introduced dispersedly and flows upwardly through the media layer; an exhaust pipe for discharging air inside the supply pipe installed on the upper or lower part of the inlet distribution pipe and the inlet part installed on the upper part of the main body; a discharge water pipe installed on the upper part of the main body and through which the nitrified water that has passed through the media layer is discharged; an air lift pipe installed vertically in the reaction tank to transfer some of the zeolite particles in the lower part of the body to the sludge separation chamber; And it is installed on the upper part of the air lift pipe and has an opening in the lower part, so that the particles transported with air fall to the media layer through the opening and are transported, and the contaminated water containing sludge desorbed from the particles in the transport process is contaminated. A nitrification tank comprising a; a sludge separation chamber to be discharged to the outside through a water pipe; an inflow distribution pipe installed in the lower part of the main body so that the nitrification treatment water from the nitrification tank is dispersedly introduced and passed through the media layer to flow upward; a discharge water pipe installed on the upper part of the main body and through which denitrification and dephosphorization water passing through the media layer is discharged; an exhaust pipe installed on the upper part of the body to discharge air inside the body; an air lift pipe installed vertically in the reaction tank to transfer some of the zeolite particles in the lower part of the body to the sludge separation chamber; And it is installed on the upper part of the air lift pipe and has an opening in the lower part, so that the particles transported with air fall to the media layer through the opening and are transported, and the contaminated water containing sludge desorbed from the particles in the transport process is contaminated. sludge separating chamber such that through the water tubes discharged to the outside; denitrification including a de-synthetic: relates to a system for high level treatment of the wastewater to be treated comprising a.

As described above, according to the present invention, since the residual amount of nitrogen and phosphorus can be minimized while using the existing water treatment facility almost as it is, it is possible to economically improve the efficiency of the existing water treatment facility, thus reducing the time and cost required for the new advanced water treatment facility be able to do

In addition, according to the present invention, it is possible to increase the biomass by using the adherent microorganisms in the nitrification process using the zeolite filter medium, and it is possible to prevent the rapid decrease in activation energy at a lower temperature of the adherent microorganisms compared to the suspended microorganisms. (Published in Environmental Technology. have.

In addition, according to the present invention, since most of the nutrients (nitrogen, phosphorus) are removed from the final effluent, reuse of the effluent is facilitated to cope with the water shortage.

1A and 1B are conceptual views and specific design examples of a system for advanced treatment of wastewater treated water according to an embodiment of the present invention applied to the rear end of a conventional water treatment process, respectively.
2a and 2b are conceptual views each showing two examples of a system according to the present invention;
3A, 3B, and 3C are diagrams showing a conceptual configuration diagram of a reaction system applied to an embodiment of the present invention and a result of the embodiment, respectively;

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings. However, the accompanying drawings are only examples for easily explaining the content and scope of the technical idea of the present invention, and thereby the technical scope of the present invention is not limited or changed. It will be natural for those skilled in the art that various modifications and changes can be made within the scope of the technical spirit of the present invention based on these examples. In addition, when reference numerals are included in the components of the claims, this is merely an example for description and is not intended to limit the components to the reference numerals.

As described above, the present invention relates to a system including a nitrification tank and a denitrification tank for removing residual nitrogen and phosphorus using wastewater treated with physical primary treatment and biological secondary treatment as influent water.

1A and 1B are conceptual views and specific design examples of a system for advanced treatment of wastewater treated water according to an embodiment of the present invention applied to the rear end of a conventional water treatment process, and FIGS. 2A and 2B are other implementations of the present invention, respectively. It is a conceptual cross-sectional view illustrating the concept of a system and its operation according to an example. Although the drawing shows two exhaust pipes on the upper part of the nitrification tank and the denitrification tank, it is natural that one exhaust pipe can perform the same function.

As shown in Figure 1a, the system for advanced treatment of wastewater treated water according to the present invention (hereinafter simply referred to as 'system according to the present invention') is, for example, a physical treatment of raw wastewater (primary sedimentation in the illustrated example). ) and biologically treated wastewater (conventional discharge water) that has passed through the sedimentation tank as the influent, and continuously passes through the nitrification tank and denitrification tank to obtain the final treated water from which nitrogen and phosphorus are simultaneously removed. As can be seen from the drawings, the present invention does not directly remove nitrogen and phosphorus from raw wastewater at the same time, but uses wastewater treated physically/biologically according to a conventional wastewater treatment process and discharged as influent as influent nitrogen to remain And it relates to an advanced purification treatment system to meet the strengthened effluent water quality standards by additionally removing phosphorus.

In the system according to the present invention, the nitrification tank 1 (the left reaction tank in FIG. 2A) includes: ① a body 11 in which the media layer M made of zeolite particles and the following components are fully or partially accommodated; ② an inflow distribution pipe 12 installed in the lower part of the main body 11 so that the influent is introduced dispersedly and flows upwardly through the media layer (M); ③ the air supply pipe 14 installed on the upper or lower part of the inlet distribution pipe and the exhaust pipe 15 installed on the upper part of the main body 11; ④ The discharge water pipe 13 installed on the upper part of the main body 11 and through which the nitrification-treated water passing through the media layer M is discharged; ⑤ an air lift pipe 16 installed vertically in the reaction tank to transfer some of the zeolite particles in the lower part of the main body 11 to the sludge separation chamber 17; and ⑥ it is installed on the upper part of the air lift pipe 16 and there is an opening in the lower part, so that the particles transported with air fall to the media layer M through the opening and are transported, and the sludge detached from the particles in the transport process Contaminated water containing is a sludge separation chamber 17 to be discharged to the outside through the contaminated water pipe 18; is a reaction tank including. A normal weir may be installed at the front end of the discharge water pipe 13 and the contaminated water pipe 18 of the nitrification tank 1 so that the water flow overflows and is discharged.

The zeolite particles are filled in the body and serve as a media layer. In the present invention, by applying a porous zeolite having ammonia adsorption ability, unlike the prior art (Registration Patent No. 10-1167488) using sand as a filter medium, ammonia is adsorbed on the surface of a zeolite media with a high specific surface area to increase the ammonia concentration on the surface of the zeolite. A favorable environment is provided for nitrifying bacteria to attach and grow.

The zeolite particles applied to the system of the present invention can be used as microbial media through molding and calcining after mixing shell (oyster, clam) powder with zeolite powder. At this time, the content (weight ratio) of the shell powder is preferably 5 to 15%, preferably around 10%. Shell powders and contain 90% or more large amount of CaCO _3, the shell powder is mixed with the calcined zeolite-containing media CaCO ₃ can obtain the effect of absorption properties, which are here combined with phosphoric acid. In addition, since CaCO ₃ functions to supplement (ie, supply alkalinity to nitrifying microorganisms) consumed when ammonia is converted to nitric acid (see Chemical Formula 1), the nitrification rate decreases toward the end of the nitrification process. This allows for more efficient nitrification (ammonia removal).

In this way, the zeolite particles applied to the system according to the present invention are porous (→ nitrifying bacteria attachment growth, ammonia adsorption) and _{contain CaCO 3} (→ phosphorus adsorption, nitrification efficiency increase). As a result, ammonia is adsorbed and physically/chemically removed from the particles during initial operation, and biological nitrification of ammonia is actively caused by _{the nitrifying microorganisms that promote adhesion and growth and CaCO 3 contained in the particles.} . Furthermore, additionally, there is an effect that a portion of phosphorus (P) is also adsorbed/removed to the particles.

Referring to the drawing (the left reaction tank in FIG. 2A), the material flow when the nitrification tank operates will be described. The flow of water is represented by a red arrow, the flow of air is represented by a blue arrow, the flow of particles is represented by a white arrow, and the flow of polluted water is represented by a green arrow.

The influent introduced dispersedly through the inflow distribution pipe passes through the media layer and is transferred to the upper part, and at this time, the ammonia nitrogen contained in the nitrifying microorganisms attached to the zeolite particles of the media layer is converted into nitrate nitrogen. The raised water (nitrification-treated water) is introduced into the reaction tank (denitrification tank in one embodiment) at the rear stage through the drain pipe on the upper part of the body. At this time, to promote nitrification, air is supplied to the media layer through an air supply pipe, and excess air is discharged through an exhaust pipe.

On the other hand, there is a separate material flow for the regeneration of particles. A part of the zeolite particles at the bottom of the body are transferred to the sludge separation chamber together with compressed air through an air lift pipe. In the process of transport, the excessively increased sludge on the particle surface is separated from the particles by the micro-impact caused by the difference in the moving speeds of particles, water and air, and the heavy particles fall to the media layer through the opening, and the light sludge is polluted with water. It is discharged to the outside through a water pipe. In this way, the zeolite particles are washed/regenerated while circulating little by little from the top of the media layer → the bottom of the media layer → the air lift tube → the sludge separation chamber → the top of the media layer → …]. In another example of the present invention (the example with the dissolved oxygen reduction tank), the sludge may be returned to the dissolved oxygen reduction tank 3 at the rear stage.

In the system according to the present invention, the denitrification tank 2 (the right reaction tank in FIG. 2a) includes: ① a body 11 in which the media layer M made of zeolite particles and the following components are fully or partially accommodated; ② an inflow distribution pipe 12 installed in the lower part of the main body 11 so that the influent is introduced dispersedly and flows upwardly through the media layer (M); ③ The discharge water pipe 13 installed on the upper part of the main body 11 and through which the denitrification and dephosphorization water passing through the media layer (M) is discharged; ④ The exhaust pipe 15 installed on the upper part of the main body 11 to discharge the air inside; ⑤ an air lift pipe 16 installed vertically in the reaction tank to transfer some of the zeolite particles in the lower part of the main body 11 to the sludge separation chamber 17; and ⑥ it is installed on the upper part of the air lift pipe 16 and there is an opening in the lower part, so that the particles transported with air fall to the media layer M through the opening and are transported, and the sludge detached from the particles in the transport process Contaminated water containing is a sludge separation chamber 17 to be discharged to the outside through the contaminated water pipe 18; is a reaction tank including. A normal weir may be installed at the front end of the discharge water pipe 13 and the contaminated water pipe 18 of the nitrification tank 1 so that the water flow overflows and is discharged.

In the present invention, the denitrification and dephosphorization tank should be under anoxic conditions, and in the denitrification tank, nitrogen gas is generated according to the denitrification reaction and is discharged through the exhaust pipe. Therefore, the denitrification tank has the same essential structure, function, and material flow as compared to the nitrification tank, except that there is no air supply pipe for air supply. Therefore, a description of the related components and material flow will be omitted.

The pH of the effluent discharged from the denitrification and dephosphorization tank according to the present invention is increased by the alkalinity generated during denitrification (refer to Chemical Formula 2 below), and the generated alkalinity is returned to the nitrification tank through internal circulation, so that in the nitrification tank It is also desirable to maximize the nitrification efficiency of In this case, the amount of returned water should be about 50% to 100% of the influent water.

As will be mentioned later, the zeolite particles applied to the denitrification tank are relatively small compared to those of the nitrification tank, so it is preferable to effectively perform a physical filtering function.

In the denitrification and dehumanization tank, the following reaction takes place. The nitrification-treated water from the nitrification tank dispersedly introduced through the inlet distribution pipe passes through the media layer and is transferred to the upper part. It is diverted and removed through the upper exhaust pipe. Meanwhile, suspended solids and phosphorus in the _{form of phosphoric acid (PO 4} ^3- ) (hereinafter abbreviated as 'phosphorus (P)') may remain in the introduced nitrification water. Suspended solids adhere to the particle surface or pores while passing through the media layer made of porous zeolite particles. _{Phosphorus (P) binds to Ca of CaCO 3} contained in the zeolite particles and is adsorbed and removed from the particles. That is, the nitrate nitrogen, phosphorus (P) and suspended solids remaining while passing through the media layer of the denitrification and dehumanization tank are removed by denitrification and particle adsorption, and the purified final treated water is discharged/discharged/reused through the discharge water pipe. On the other hand, suspended solids adsorbed to the particles and phosphorus (P) are desorbed from the particles during the cycle-washing/regeneration process of the zeolite particles described above and discharged to the outside through the contaminated water pipe.

In the system according to the present invention, denitrification of nitrate nitrogen transferred from the nitrification tank of the previous stage proceeds only when the denitrification and dephosphorization tank maintains anoxic conditions. However, since air is supplied in the nitrification tank in the previous stage, if dissolved oxygen remains in the nitrification treatment water that has passed through the nitrification tank, there is a fear that denitrification may not be performed smoothly in the denitrification tank. In order to prevent such a problem from occurring, in the system according to the present invention, it is preferable to additionally install a dissolved oxygen reduction tank 3 between the nitrification tank and the denitrification tank (see FIG. 2b ). In the added dissolved oxygen reduction tank 3, as shown in FIG. 2b, contaminated water containing sludge discharged from the nitrification tank is introduced into the lower part of the reduction tank, and a kind of filtration layer is formed by the sludge layer at the bottom of the reduction tank, and the nitrification tank It is preferable that the nitrification treated water discharged from the sludge is transferred to the lower part of the sludge filtration layer and then transferred to the upstream so that it is discharged from the upper part of the abatement tank. Due to the mechanism of this dissolved oxygen reduction tank, the dissolved oxygen remaining in the nitrification water is consumed during the residence time and becomes sludge. will be imported

As described above, nitrate nitrogen contained in the influent flowing into the denitrification and dehumanization tank is converted into gaseous nitrogen and removed by denitrification microorganisms using the remaining carbon source. However, for example, when the treated water (very little organic matter) that has passed through the existing wastewater treatment facility passes through the nitrification tank and the dissolved oxygen reduction tank in the present invention again, the organic matter contained therein is continuously consumed and flows into the denitrification tank There is a fear that the carbon source necessary for the denitrification microorganisms to act may become insufficient. Therefore, it is preferable that a supply tank for supplying an organic carbon source (eg, methanol) is added to the front end of the denitrification and dehumanization tank so that the growth and activity of the denitrification microorganisms can be properly maintained.

On the other hand, as described above, phosphorus (P) in the form of phosphoric acid _{binds with CaCO 3} contained in the zeolite particles and is adsorbed/removed by the particles. That is, phosphorus (P) remaining in the treated water passing through the wastewater treatment facility is removed in the nitrification tank and denitrification tank by the zeolite particles containing _{CaCO 3 .} However, in some cases, a supply tank for supplying iron salt or iron hydrate (hereinafter referred to as 'iron salt') may be added to the nitrification tank or denitrification tank in order to remove the phosphorus (P) remaining by this. The supplied iron salt is adsorbed to zeolite particles with a large specific surface area and many pores, and phosphorus (P) in the form of phosphoric acid is ionically bonded to the iron salt. Therefore, phosphorus (P) is adsorbed to the zeolite particles through the iron salt.

Phosphorus (P) remaining in this way _{is adsorbed by CaCO 3} contained in the zeolite particles and iron salts bound to the particles. The adsorbed phosphorus (P) is separated from the particles in the sludge separation chamber and removed as described above.

As a result of operating the pilot plant of the system according to the present invention, it was confirmed that it is more efficient to apply zeolite particles of different diameters to the nitrification tank and the denitrification tank. That is, the zeolite particle diameter of 3 to 6 mm was more useful for nitrification in the nitrification tank, and 1 to 2 mm in the denitrification and dephosphorization tank had the additional effect of not only denitrification but also the zeolite particle layer acting as a physical filtering layer. .

[Experimental example]

1. Operation of small nitrification tank at low temperature

In this experiment, [A]A2O, [B]A2O+Zeolite (100%) filter media nitrification tank, [C]A2O+Zeolite (85%), CaCO ₃ (5% ) Using a shell powder (10%) filter material nitrification tank, an experiment on nitrogen removal according to temperature was performed, and the hydraulic residence time of the A2O reactor was about 7 hours, and the sludge age (SRT) was 16 to 25 days. A conceptual diagram of each experimental example is shown in FIG. 3A, and the results are shown in FIGS. 3B and 3C.

<Experimental conditions and nitrification tank specifications>

[A]A2O (In order to keep the nitrification time of B and C the same, the nitrification tank of A is enlarged. In the case of floating type, it is an indirect experiment to show that nitrification is insufficient at low temperature.)

[B] A2O+Zeolite (100%) filter media nitrification tank

[C]A2O+Zeolite (85%), CaCO ₃ (5%) Shell powder (10%) Filter material nitrification tank

As can be seen in Fig. 3b, the result of the example, the COD removal rate (above chart) according to the experimental result did not show a significant difference, but in the removal of ammonia, about 10 ~ The removal efficiency was increased by about 20% more, and it can be seen that there is a big difference between the floating growth method and the adhesion growth method depending on the temperature (the chart below). In the case of the floating growth method [A], the nitrification rate decreased sharply after 15℃, but in the case of the adhesion growth methods [B] and [C], it was maintained at over 70% even at 8℃, and in the case of [A], the nitrification rate of 20% was confirmed did

Compact reactor operation period last low temperature (operating temperature of 7 ℃) one time only A2O zeolite filter media surface of the bioreactor and Bacteria analysis of the zeolite filter media (Genus) Results [B], [C] process of Nitrosomonas, Nitrospira It can be seen that the % is high, and in particular, a large amount of nitrifying microorganisms adhered and grown on the filter medium of the [C] process, confirming the possibility of concentrated growth of nitrifying microorganisms (FIG. 3c).

2. Pilot plant operation for nitrification and denitrification

In order to check whether the nitrification and denitrification and dephosphorization systems employed in the system according to the present invention operate smoothly, a pilot scale equipment was manufactured and operated at a scale of 50 to 100 tons per day.

The specifications and operating conditions of the reactor were as follows.

The experimental results were as follows (unit: mg/L).

As such, when the system for advanced treatment of wastewater treated water according to the present invention is applied, the effluent (TN 20 mg/L, TP 0.2 mg/L) exceeding the effluent water quality standards (TN 20 mg/L, TP 0.2 mg/L) ) is additionally treated to sufficiently meet the water quality standards.

M. Media layer
1. nitrification tank
2. Denitrification and de-manufacturing
3. Reduction of dissolved oxygen
11. Main body 12. Inlet distribution pipe 13. Outlet water pipe
14. Air supply pipe 15. Exhaust pipe 16. Air lift pipe
17. Sludge separation chamber 18. Contaminated water pipe

Claims (7)

A system for removing residual nitrogen and phosphorus by using treated water physically/biologically treated as wastewater as influent,
(A) a body in which the media layer made of zeolite particles and the following components are accommodated in whole or in part;
an inflow distribution pipe installed at the lower part of the main body so that the influent water is introduced dispersedly and flows upwardly through the media layer;
a discharge water pipe installed on the upper part of the main body and through which the nitrified water that has passed through the media layer is discharged;
an air supply pipe installed on the upper or lower part of the inlet distribution pipe and an exhaust pipe installed on the upper part of the main body to discharge internal air;
an air lift pipe installed vertically in the reaction tank to transfer some of the zeolite particles in the lower part of the body to the sludge separation chamber; and
It is installed in the upper part of the air lift pipe and has an opening in the lower part, so that the particles transported with air fall to the media layer through the opening and are transported. A nitrification tank comprising; a sludge separation chamber to be discharged to the outside through a
(B) a body in which the media layer made of zeolite particles and the following components are accommodated in whole or in part;
an inflow distribution pipe installed in the lower part of the main body so that the nitrification treatment water from the nitrification tank is dispersedly introduced and passed through the media layer to flow upward;
a discharge water pipe installed on the upper part of the main body and through which denitrification and dephosphorization water passing through the media layer is discharged;
an exhaust pipe installed on the upper part of the body to discharge air inside the body;
an air lift pipe installed vertically in the reaction tank to transfer some of the zeolite particles in the lower part of the body to the sludge separation chamber; and
It is installed in the upper part of the air lift pipe and has an opening in the lower part, so that the particles transported with air fall to the media layer through the opening and are transported. de denitrification artificial containing; the separation chamber through the sludge to be discharged to the outside:
A system for advanced treatment of wastewater treated water comprising a.
The method according to claim 1,
A system for advanced treatment of treated wastewater, characterized in that a dissolved oxygen reduction tank is installed between the nitrification tank and the denitrification tank.
The method according to claim 1,
A system for advanced treatment of treated wastewater, characterized in that a supply tank for supplying an organic carbon source and iron salt is added to the front end of the denitrification and dephosphorization tank.
4. The method according to any one of claims 1 to 3,
The system for advanced treatment of wastewater treatment, characterized in that the zeolite of the denitrification tank or the nitrification tank and the denitrification tank contains 5 to 10% of CaCO _{3 .}
5. The method according to claim 4,
The CaCO ₃ is a shell powder or a system for advanced treatment of treated wastewater, characterized in that derived from shell.
4. The method according to any one of claims 1 to 3,
A system for advanced treatment of treated wastewater, characterized in that a portion of the denitrification and dephosphorization water discharged from the denitrification and dephosphorization tank is internally circulated to the nitrification tank to supply alkalinity to the nitrification tank.
4. The method according to any one of claims 1 to 3,
The system for advanced treatment of wastewater treatment water, characterized in that the particle diameters of the zeolite in the nitrification tank and the denitrification tank are 3 to 6 mm and 1 to 2 mm, respectively.

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