KR20140140140A - Method of water treatment and system using the same - Google Patents

Abstract

The present invention provides a water treatment method and a water treatment system using the same, the water treatment method comprising: a dissolved air flotation step (200) of inputting, into a dissolved air flotation tank (20), supernatant liquid generated from an anaerobic digestion step (100) of inputting wastewater into an anaerobic digester (10) to remove suspended solids; a first filtering step (300) of inputting, into a first bio-filter (30), treated water discharged from the dissolved air flotation step (200) to nitrate ammonia-nitrogen and remove organic matters; a carbon source injection step (410) of injecting acetic acid, which has been generated in the anaerobic digestion step (100), as an inner carbon source into the treated water discharged from the first filtering step (300); a second filtering step (400) of inputting, into a second bio-filter (40), the treated water discharged from the first filtering step (300) and having the inner carbon source injected therein to remove the nitrate nitrated in the first filtering step (300) under anoxic conditions; a third filtering step (500) of inputting, into a third bio-filter (50), the treated water discharged from the second filtering step (400) to remove suspended solids and remaining organic matters; and a discharge step (600) of discharging the treated water discharged from the third filtering step (500). Also, the present invention provides a water treatment system using the same. The water treatment method treats anaerobic digestion supernatant liquid efficiently at low costs, increases economical efficiency by recycling resources through the production of bio-energy (methane gas), and is eco-friendly by inhibiting aquatic eutrophication and the generation of red tides caused by the discharge of the supernatant liquid.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a water treatment method,

Field of the Invention The present invention relates to an environmental field, and more particularly, to a water treatment method and a water treatment system using the same.

In general, since livestock wastewater contains a high concentration of organic matter and nitrogen components and excessive suspended substances, it is difficult to treat livestock wastewater, and the characteristics and characteristics of the wastewater are different from each other, There is a problem.

In addition, food wastes have a problem in that they are odorous when collecting and transporting, because they have a large amount of water and salt, unlike other wastes, and are difficult to handle and manage in subsequent processing and final disposal due to their rapid decay characteristics.

When food waste is to be composted, it is troublesome to add a moisture control agent in order to maintain a proper moisture content. In the final disposal, since the combustion efficiency is low due to high water content in the incineration treatment, And the high water content in the case of landfill causes a large amount of high concentration leachate to increase the treatment cost and contaminate the surrounding groundwater and soil.

As a system for treating organic wastewater of high concentration such as livestock wastewater, food wastes, and manure, energy production technology using biomass is mainly performed, and in particular, a method using anaerobic digestion is obtained as a byproduct of wastewater or waste treatment Through the production of methane, two effects of solving environmental problems and securing energy can be achieved at the same time.

The anaerobic digestion of the above organic solid waste is defined as a process of collectively treating two or more organic wastes having different physical and chemical properties in a single digestion tank.

However, the anaerobic digestion technology has problems such as degradation of the digestibility due to accumulation of scum and oil, energy consumption due to the heating facility, relatively long hydraulic retention time, and also problems such as a high concentration of nitrogen generated after anaerobic digestion And the problem of reduced economic efficiency.

Generally, the supernatant of anaerobic digestion tank contains TSS 20,000 mg / L or more, COD 14,000 mg / L or more, BOD 2,000 mg / L or more, NH ₄ ⁺ -N 2,000 mg / L or more, TN 3,000 mg / L or higher.

Such a supernatant can be transported to a nearby public sewage treatment plant and processed, but the procedure is very complicated. If the transfer process is not possible, the supernatant liquid is sprayed on the agricultural land, which causes various problems such as adverse effects on crops .

Therefore, it is urgent to develop an optimized water treatment system capable of proper treatment of the anaerobic digestion supernatant and direct discharge to the in-situ water system.

In addition, the treatment of the anaerobic digestion supernatant does not only contain high concentrations of nitrogen and phosphorus but also has high suspended solids concentration. Therefore, in order to effectively treat the anaerobic digestion effluent, pretreatment of suspended solids and high concentration dissolved substances (SBOD, SCOD, NOx, etc.) Biological treatment for elimination, chemical treatment for treatment of phosphorus needs to be carried out properly.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide an anaerobic digestion supernatant which is processed at low cost and high efficiency, is economically improved by recycling resources through the production of bioenergy (methane gas) An eco-friendly water treatment method by suppressing the occurrence of eutrophication and red tide, and a water treatment system using the same.

In order to solve the above problem, the present invention provides a method for removing suspended solids from a supernatant liquid generated from an anaerobic digestion step (100) in which wastewater is introduced into an anaerobic digestion tank (10) Step 200; A first filtering step (300) for nitrifying ammonia nitrogen with respect to the treated water discharged from the dissolved air floating step (200) and charging the first biofilter (30) to remove organic matter; A carbon source injection step (410) for injecting acetic acid generated in the anaerobic digestion step (100) as an internal carbon source into the treated water discharged from the first filtration step (300); The second biofilter 40 is operated to remove the nitrified nitrate from the treated water discharged from the first filtration step 300 injected with the internal carbon source in the first filtering step 300 under anoxic condition through denitrification, A second filtration step (400) for introducing the second filtration step; A third filtration step (500) for feeding the treated water discharged from the second filtration step (400) to the third biofilter (50) so as to remove suspended matters and residual organic matter; And a discharging step (600) of discharging the treated water discharged from the third filtering step (500).

And a recycling step (700) of charging the sludge concentrated water generated in the first filtering step (300) to the third filtering step (500) into the anaerobic digestion tank (10) and recirculating the same.

An internal circulation step (step (b)) in which the first filtration step (300) or the second filtration step (400) is performed again for the treated water having a large amount of residual organic matter among the treated water discharged from the third filtration step 510). ≪ / RTI >

The inner circulation step 510 preferably has an internal circulation ratio of 0.5 to 2.0.

The anaerobic digestion step (100) includes an input step (110) of injecting wastewater into a feed tank; The inflow water that has passed through the input step 110 is supplied to the anaerobic digestion tank 10 in the order of first-in first-out 14, second-15 and third-round 16, After the independent digestion has proceeded, moving to the next zone (140); An acid forming step 120 for forming acetic acid and fermenting methane simultaneously with the digestion of the influent water; And methane production step 130; And a sludge discharging step (180) for discharging the sludge generated in the digestion process of the inflow water from time to time. In the carbon source injection step (410), the treated water discharged from the first filtering step (300) It is preferable to inject acetic acid generated in the forming step 120 as an internal carbon source.

The first biofilter 30, the second biofilter 40, and the third biofilter 50 contain a carrier on which a biofilm is formed, and the first to third filtration steps 300, In step 500, it is preferable that the carrier oxidizes the organic matter.

The third filtration step (500) includes a coagulant injection step (520) for injecting a coagulant to remove phosphorus from the treated water discharged from the second filtration step (400); A rapid mixing step (530) in which the treated water into which the coagulant is injected is injected into the line mixer (52) for rapid mixing; And a direct filtration step (540) in which the rapidly mixed water is injected into the third biofilter (50) to form a flux, and then the filtration is performed by the carrier.

The present invention is a water treatment system using the water treatment method, comprising: a dissolved air floating tank (20) configured to remove suspended solids from a supernatant generated from the anaerobic digestion tank (10); A first biofilter 30 configured to nitrate ammonia nitrogen with respect to the treated water discharged from the dissolved air floating tank 20 and remove organic matter; A carbon source injection unit 41 for injecting acetic acid generated from the anaerobic digestion tank 10 as an internal carbon source into the treated water discharged from the first biofilter 30; A second biofilter 40 formed to remove nitrified nitrate from the first biofilter 30 through denitrification with respect to the treated water discharged from the first biofilter 30 and operated under anaerobic conditions; A third biofilter 50 configured to remove suspended solids and remaining organic matter from the treated water discharged from the second biofilter 40; And a discharge unit (60) configured to discharge the treated water discharged from the third biofilter (50).

The anaerobic digestion tank (10) includes an input unit (11) for inputting wastewater into an input tank; A first zone 14, a second zone 15, and a third zone 16, which are formed so as to move to the next zone after independently extinguishing the inflow water passing through the introduction unit 11 in the order of first- Zone 17; An acid forming part 12 formed at the same time as the digestion process of the influent water to form acetic acid and perform methane fermentation; And methane production section (13); And a sludge discharge unit (18) configured to discharge sludge generated in the digestion process of the influent water from time to time. In the carbon source injection unit (41), the treatment water discharged from the first biofilter (30) It is preferable that the acetic acid produced in the acid forming portion 12 is injected as an internal carbon source.

A coagulant injection unit 51 configured to inject a coagulant to remove phosphorus from the treated water discharged from the second biofilter 40; And a line mixer (52) configured to rapidly mix the treated water into which the coagulant is injected, wherein the third biofilter (50) formed to inject the rapidly mixed water through the line mixer (52) It is preferable that filtration is performed by a carrier.

The present invention relates to an eco-friendly water treatment method by treating an anaerobic digestion supernatant with low cost and high efficiency, increasing economic efficiency by recycling resources through the production of bio-energy (methane gas), suppressing eutrophication of water system and occurrence of red tide due to discharge of supernatant, We propose a water treatment system using this.

FIG. 1 is a view illustrating a water treatment method according to the present invention and a water treatment system using the same.
1 is a first configuration diagram of an embodiment;
2 is a second configuration diagram of an embodiment;
3 is a schematic view of the anaerobic digestion stage.
4 is a configuration diagram of a third filtration step;

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

1, the water treatment method according to the present invention is a method for removing suspended solids from the supernatant liquid generated from the anaerobic digestion step 100 in which wastewater is introduced into the anaerobic digestion tank 10, (200); < / RTI > A first filtration step (300) for nitrifying ammonia nitrogen with respect to the treated water discharged from the dissolved air floating step (200) and charging the first biofilter (30) to remove organic matter; A carbon source injection step (410) for injecting acetic acid generated in the anaerobic digestion step (100) as an internal carbon source for the treated water discharged in the first filtration step (300); The second biofilter 40 is operated to remove nitrate nitrate from the first filtration step 300 injected with the internal carbon source through the denitrification reaction in the first filtration step 300 under the anoxic condition with respect to the treated water discharged from the first filtration step 300 A second filtration step (400) for charging; A third filtration step (500) of charging the third biofilter (50) to remove suspended solids and residual organic matter from the treated water discharged from the second filtration step (400); And a discharge step (600) for discharging the treated water discharged in the third filtering step (500).

Generally, the supernatant from the anaerobic digestion stage (100) has a high pollutant load, and when it is pumped into a livestock farm, secondary pollution that adversely affects the crops is caused.

In order to prevent this, the present invention proposes a water treatment method for separately treating the supernatant generated from the anaerobic digestion step (100).

In addition, the anaerobic digestion supernatant contains not only high concentrations of nitrogen and phosphorus, but also high suspended solids concentrations.

Accordingly, the present invention can provide a highly efficient filtration step (300, 400, 500) using a biofilm at the downstream to effectively remove high-concentration suspended solids (SBOD, SCOD, NOx, etc.) To a level that can be discharged directly to the water system.

As a result, it is possible to reuse high-concentration wastewater as a whole resource, which is highly desirable from the economic and environmental point of view, and it is possible to suppress the occurrence of secondary films and red tides by improving the water quality of the discharged water.

Such a water treatment method can be effectively applied as a pretreatment of a water source, a pretreatment of wastewater, and a pretreatment method of a seawater desalination plant.

The anaerobic digestion step (100) of the present invention is characterized in that it is performed in the order of first-in-first-out.

In other words, a first-in-first-out type anaerobic digestion step (100) in which high purity methane gas (bio-energy) production is easy and continuous operation is carried out for treatment of high concentration organic wastewater such as livestock wastewater, food wastewater, A dissolved air flooding step 200 for treating the supernatant, and a first to third filtration steps 300, 400 and 500 using a biofilm are constituted as a subsequent process so that methane gas, compost, liquid fertilizer and reused water can be converted into resources And to ensure eco-friendliness.

Specifically, the first-in-first-out means a method of first treating the supernatant which is generated first or put into the dissolved air floating tank 20.

The anaerobic digestion step 100 of the present invention is an anaerobic digestion step in which the acid forming step 120 and the methane production step 130 are simultaneously performed in the order of first-in first-out and the first zone of the anaerobic digestion tank 10 designed to move to the next anaerobic digestion zone A step 140 is performed to move to the first zone 11, the second zone 12 and the third zone 13, and the fourth zone 14.

That is, since the anaerobic digestion step 100 is performed in the order of first-in first-out, a large amount of carbon in the first zone 11, the second zone 12 and the third zone 13 and the fourth zone 14 of the anaerobic digestion tank 10 It is easy to extract the carbon as a carbon source.

This carbon source is acetic acid or a volatile vasoconstric acid, and it is a feature of the present invention that a carbon source injection step (410) is performed in which the treated water discharged from the first filtration step (300) is injected as an internal carbon source.

In other words, the second filtration step 400 is a step of converting nitrate into nitrogen gas through a denitrification reaction and discharging it to the air to remove it. At this time, as an electron acceptor required for denitrification, Acetic acid.

This has the advantage of being very economical and efficient because it can effectively remove nitrogen in the treated water without the need to inject additional external carbon sources such as methanol.

Each step constituting the water treatment method of the present invention will be described in detail as follows (Figs. 1 and 2).

The anaerobic digestion step 100 of the present invention includes a charging step 110 and a charging step 110 in which wastewater is introduced into the charging unit 11 before the supernatant is treated in the anaerobic digestion step 100 The inflow water passed through the anaerobic digestion tank 10 is subjected to independent digestion in the order of first-in-first-out 14, second-15, third-zone 16 and fourth-in- (140), an acid forming step (120) for forming acetic acid and fermenting methane simultaneously with the digestion process of the influent water; And methane production step 130; And a sludge discharging step 180 for discharging the sludge generated in the extinguishing process of inflow water from time to time (FIG. 3).

As described above, since the continuous anaerobic digestion is performed in the order of first-in-first-out, the efficiency of the anaerobic digestion process can be enhanced and the operation can be flexibly performed with respect to the organic matter load.

In addition, it is easy to partially extract a certain region containing carbon.

Here, a carbon source injection step (410) is performed in which the partially extracted carbon source, i.e., acetic acid, is injected as an internal carbon source to the treated water discharged in the first filtration step (300).

In addition, since the new raw material is injected into the deep part in the anaerobic digestion step (100), the purity and production amount of methane gas can be increased by implementing an extremely anaerobic state.

Since the generated methane gas can be supplied to the district heating or the vinylhouse heating fuel in the winter and biogas power generation, it can solve the wastewater treatment problem of the livestock farmers, reduce the wastewater treatment cost, and build the resource recirculating water system Which can contribute to the improvement of farm household income.

In order to treat the supernatant resulting from the anaerobic digestion step 100, the dissolved air floatation step 200 is first performed.

The dissolved air floatation step 200 is a step of separating and removing the floating particulate matter of the anaerobic digestion solution dml using micro-air.

The principle of elimination is to dissolve air in the water under pressure and open it to the treated water, so that the air dissolved in the water becomes a large number of fine bubbles.

The bubbles attach the floating substance in the water to reduce the specific gravity of the floating substance, and float the floating substance onto the water.

Since the dissolved air floating tank 20 has a much higher surface load ratio than the conventional sedimentation tank and the residence time of the treated water is also very short, the size of the tank can be reduced and the site area is also reduced.

Also, the load of the suspended material is reduced through the dissolved air floating step (200), so that the effect of increasing the backwashing period of the first filtration step (300) in the subsequent stage can be obtained.

A first filtering step 300 is performed in which the treated water discharged in the dissolved air floating step 200 is supplied to the first biofilter 30.

The first biofilter 30 contains a carrier on which a biofilm is formed. The carrier oxidizes and decomposes organic matter and nitrifies ammonia nitrogen.

The excess suspended material that has not been completely removed in the dissolved air floatation step 200 is removed by filtration and adsorption.

A second filtration step 400 is performed in which the treated water discharged from the first filtration step 300 is supplied to the second biofilter 40.

The second filtration step (400) is performed under anaerobic conditions. In the first filtration step (300), the nitrified nitrate is converted into nitrogen gas through the denitrification and discharged to the air.

As described above, acetic acid generated in the anaerobic digestion step (100) can be used as an electron acceptor required for the denitrification reaction.

Therefore, a carbon source injection step 410 for injecting acetic acid generated in the anaerobic digestion step 100 as an internal carbon source is performed on the treated water discharged in the first filtration step 300 before the second filtration step 400.

This eliminates the need for additional external carbon source injection, thereby ensuring economical efficiency and efficiently removing nitrogen.

A third filtration step 500 is performed in which the treated water discharged from the second filtration step 400 is supplied to the third biofilter 50.

In the third filtration step 500, the remaining suspended organic material in the treated water and the unused organic material in the denitrification process of the second filtration step 400 are oxidized.

In addition, nitrification of some ammonia nitrogen occurs, and a process for completely removing suspended solids and colloidal particulate matter is performed in order to discharge the final treated water.

Like the first biofilter 30, the second biofilter 40 and the third biofilter 50 also contain a carrier having a biofilm formed thereon. The carrier oxidizes the organic matter.

The third filtration step 500 is configured as follows to more effectively remove phosphorus in the treated water (FIG. 4).

First, a coagulant injection step (520) is performed in which the coagulant is injected to remove phosphorus from the treated water discharged from the second filtration step (400).

A rapid mixing step 530 is performed in which the treated water into which the coagulant is injected is introduced into the line mixer 52 and rapidly mixed.

A direct filtration step 540 is performed in which the rapidly mixed water is injected into the third biofilter 50 to form a flock by the water flow in the lower space and then filtered by the carrier.

Through such a construction, direct filtration (540) is performed by using a coagulant (PAC, Alum) instead of a coagulation sedimentation method in order to remove phosphorus in the treatment water, so that the amount of coagulant used can be greatly reduced, , The phosphor can be removed more efficiently.

Finally, a discharging step 600 is performed for discharging the treated water discharged in the third filtering step 500.

Particularly, in the internal circulation step (step S 300) in which the first filtration step 300 or the second filtration step 400 is performed again for the treated water having a large amount of residual organic matter among the treated water discharged in the third filtration step 500 510).

In other words, it is possible to reliably prevent the second pollution of the soil by re-finishing the treated water which does not satisfy the discharge condition, and to discharge the treated water in which residual organic matter is reliably removed.

It is preferable that the internal circulation ratio in the internal circulation step 510 is 0.5 to 2.0.

This makes it possible to more reliably remove the remaining nitric acid compounds and to prevent the biofilm 30 on the surface of the carrier inside the first biofilter 30, the second biofilter 40 and the third biofilter 50, .

In the water treatment method of the present invention, a recycle step 700 is performed in which the sludge concentrated water generated in each of the first to third filtration steps 300 to 500 is introduced into the anaerobic digestion tank 10 and recirculated 2).

Accordingly, the sludge is not generated in the supernatant treatment step, that is, the dissolved air flooding step (200) to the third filtration step (500), and the sludge generation amount in the entire step including the anaerobic digestion step (100) can be minimized.

This makes it possible to greatly reduce the maintenance cost of the entire process, thereby remarkably improving the economical efficiency.

In addition, there is an advantage that secondary contamination, which may occur when the sludge-concentrated water is discharged as it is, can be reliably prevented.

Next, a water treatment system using the water treatment method of the present invention will be described.

First, the suspended liquid is introduced into the dissolved air floating tank 20 to remove suspended solids from the supernatant liquid generated from the anaerobic digestion tank 10.

The ammonia nitrogen is nitrified to the treated water discharged from the dissolved air floating tank 20, and the ammonia nitrogen is charged into the first biofilter 30 to remove organic matter.

Acetic acid generated from the anaerobic digestion tank 10 is injected into the treated water discharged from the first biofilter 30 as an internal carbon source through the carbon source injection unit 41.

In order to remove the nitrified nitrate from the first biofilter 30 through the denitrification reaction, the treated water discharged from the first biofilter 30 is introduced into the second biofilter 40 operated under anaerobic conditions .

The third biofilter 50 is charged with the treated water discharged from the second biofilter 40 to remove suspended substances and residual organic matter.

And discharges the treated water discharged from the third biofilter (50) through a discharge unit (60) configured to discharge the same.

Particularly, the anaerobic digestion tank 10 is provided with an inlet 11 for introducing wastewater into a charging tank, and an inlet and an outlet for inflow water passing through the charging unit 11, 1 zone 14, 2 zone 15 and 3 zone 16, and 4 zone 17.

Also, an acid forming part 12, which is formed so that acetic acid is formed and methane fermentation is performed simultaneously with the digestion process of the influent water; And a methane production unit 13. The sludge discharge unit 18 is configured to discharge the sludge generated during the extinguishing process of inflow water from time to time.

This configuration is advantageous in that it is easy to partially collect the carbon-containing portion in the anaerobic digestion tank 10.

Therefore, acetic acid generated in the acid forming part 12 is injected as an internal carbon source into the treated water discharged from the first biofilter 30 through the carbon source injecting part 41.

As a result, there is no need to separately inject an external carbon source, which is advantageous in that it can be economically secured and nitrogen in the treated water can be removed more efficiently.

In addition, a coagulant injection unit 51 formed to inject the coagulant into the treated water discharged from the second biofilter 40 to remove phosphorus, and a line mixer 52 formed to rapidly mix the treated water into which the coagulant is injected .

The treated water rapidly mixed by the line mixer 52 is put into the third bio-filter 50 to form a flock, and then filtration is performed by the carrier.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the appended claims. It is to be understood that both the technical idea and the technical spirit of the invention are included in the scope of the present invention.

10: anaerobic digestion tank 11:
14: 1 Zone 15: 2 Zone
16: 3 Area 17: 4 Area
18: sludge discharge part 20: dissolved air floating tank
30: first biofilter 40: second biofilter
41: carbon source injection unit 50: third biofilter
52: coagulant injection unit 53: line mixer
60: discharging part 100: anaerobic digestion step
110: Addition step 120: Acid formation step
130: Methane production stage
140: After digestion has progressed, move to the next zone
180: sludge discharge step 200: dissolved air float step
300: first filtration step 400: second filtration step
410: carbon source injection step 500: third filtration step
510: internal circulation step 520: coagulant injection step
530: rapid mixing step 540: direct filtration step
600: discharging step 700: recirculating step

Claims (10)

A dissolved air floatation step (200) of injecting waste water into a dissolved air floating tank (20) so as to remove suspended solids from the supernatant liquid generated from the anaerobic digestion step (100) into which the wastewater is introduced into the anaerobic digestion tank (10);
A first filtering step (300) for nitrifying ammonia nitrogen with respect to the treated water discharged from the dissolved air floating step (200) and charging the first biofilter (30) to remove organic matter;
A carbon source injection step (410) for injecting acetic acid generated in the anaerobic digestion step (100) as an internal carbon source into the treated water discharged from the first filtration step (300);
The second biofilter 40 is operated to remove the nitrified nitrate from the treated water discharged from the first filtration step 300 injected with the internal carbon source in the first filtering step 300 under anoxic condition through denitrification, A second filtration step (400) for introducing the second filtration step;
A third filtration step (500) for feeding the treated water discharged from the second filtration step (400) to the third biofilter (50) so as to remove suspended matters and residual organic matter;
A discharging step 600 discharging the treated water discharged from the third filtering step 500;
And water. The method according to claim 1,
A recycling step (700) of charging the sludge concentrated water generated in each of the first filtering step (300) to the third filtering step (500) into the anaerobic digestion tank (10)
Further comprising the steps of: The method according to claim 1,
An internal circulation step (step (b)) in which the first filtration step (300) or the second filtration step (400) is performed again for the treated water having a large amount of residual organic matter among the treated water discharged from the third filtration step 510);
Further comprising the steps of: The method of claim 3,
The inner circulation step (510)
Wherein the internal circulation ratio is 0.5 to 2.0. The method according to claim 1,
The anaerobic digestion step (100)
An input step (110) for inputting wastewater into the input tank;
The inflow water that has passed through the input step 110 is supplied to the anaerobic digestion tank 10 in the order of first-in first-out 14, second-15 and third-round 16, After the independent digestion has proceeded, moving to the next zone (140);
An acid forming step 120 for forming acetic acid and fermenting methane simultaneously with the digestion of the influent water; And methane production step 130;
And a sludge discharge step (180) for discharging the sludge generated during the digestion process of the inflow water from time to time,
Wherein the carbon source injection step (410) injects acetic acid generated in the acid formation step (120) as the internal carbon source into the treated water discharged from the first filtration step (300). The method according to claim 1,
The first biofilter 30, the second biofilter 40, and the third biofilter 50 contain a carrier on which a biofilm is formed,
Wherein the first filtration step (300) to the third filtration step (500) comprises oxidation of organic matter by the carrier. The method according to claim 6,
The third filtering step (500)
A flocculant injection step (520) for injecting a flocculant to remove phosphorus from the treated water discharged from the second filtration step (400);
A rapid mixing step (530) in which the treated water into which the coagulant is injected is injected into the line mixer (52) for rapid mixing;
A direct filtration step (540) in which the rapidly mixed water is injected into the third bio-filter (50) to form a fl uid, and then the filtrate is filtered by the carrier
And water. A water treatment system using the water treatment method according to any one of claims 1 to 7,
A dissolved air floating tank 20 formed to remove suspended solids from the supernatant liquid generated from the anaerobic digestion tank 10;
A first biofilter 30 configured to nitrate ammonia nitrogen with respect to the treated water discharged from the dissolved air floating tank 20 and remove organic matter;
A carbon source injection unit 41 for injecting acetic acid generated from the anaerobic digestion tank 10 as an internal carbon source into the treated water discharged from the first biofilter 30;
A second biofilter 40 formed to remove nitrified nitrate from the first biofilter 30 through denitrification with respect to the treated water discharged from the first biofilter 30 and operated under anaerobic conditions;
A third biofilter 50 configured to remove suspended solids and remaining organic matter from the treated water discharged from the second biofilter 40;
A discharge unit 60 formed to discharge the treated water discharged from the third biofilter 50;
Water treatment system. 9. The method of claim 8,
The anaerobic digester (10)
A charging unit (11) for charging wastewater into a charging tank;
A first zone 14, a second zone 15, and a third zone 16, which are formed so as to move to the next zone after independently extinguishing the inflow water passing through the introduction unit 11 in the order of first- Zone 17;
An acid forming part 12 formed at the same time as the digestion process of the influent water to form acetic acid and perform methane fermentation; And methane production section (13);
And a sludge discharge unit (18) configured to discharge sludge generated during the digestion process of the inflow water from time to time,
Wherein the acetic acid generated in the acid forming part (12) is injected as an internal carbon source into the treated water discharged from the first biofilter (30) in the carbon source injecting part (41). 9. The method of claim 8,
A coagulant injection unit (52) configured to inject a coagulant to remove phosphorus from the treated water discharged from the second biofilter (40);
A line mixer 53 configured to rapidly mix the treated water into which the coagulant is injected;
Further,
Wherein the first biofilter (50) is formed with a flock by the third biofilter (50) formed to inject the rapidly mixed water through the line mixer (52), and then filtered by the carrier.

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