KR20060024601A - Biological denitrification process using sulfur-utilizing chemolithoautotroph - Google Patents

Abstract

The present invention relates to a biological nitrogen removal process using sulfur oxidation autotrophic bacteria and a device used therein, and more particularly has a front flow-out structure, the porous plate-like media of the sulfur is fixed in the sulfur denitrification reactor vertically stacked, Nitrogen contained in the raw water by arranging a floating ball to block the inflow of oxygen and sunlight from the outside on the water surface of the sulfur denitrification reactor, and injecting raw water containing nitrogen to perform autotrophic denitrification reaction by sulfur oxidation The present invention relates to a denitrification process for eliminating and the apparatus used therefor.

In the denitrification process using the apparatus according to the present invention, the concentration of nitrogen oxidized autotrophic bacteria, which is characterized by reducing nitrate ions and oxidizing sulfur to release sulfuric acid ions under anoxic conditions, rapidly increases the concentration of nitrogen present in water. Reduce the amount of time and treat effluent from public sewage treatment plant and factory wastewater treatment plant containing nitrate nitrogen and reuse it for process water, cleaning water, landscaping water or toilet washing water, or nitrogen concentration compared to organic matter concentration. Is suited for the treatment of relatively high leachate, livestock wastewater, etc.

Autotrophic bacteria, denitrification, nitrate nitrogen, plate media, autotrophic denitrification, suspended balls, outflow weirs, biological denitrification, sulfur

Description

BIOLOGICAL DENITRIFICATION PROCESS USING SULFUR-UTILIZING CHEMOLITHOAUTOTROPH}

1 is a process chart showing a denitrification process using a denitrification apparatus according to the present invention.

Figure 2a is a schematic diagram of a denitrification apparatus according to the present invention.

FIG. 2B is a schematic view showing a plate-like media in which sulfur is immobilized in the denitrification reactor of FIG. 2A; FIG.

Figure 3 is a schematic diagram showing a denitrification device produced in an embodiment of the present invention.

Figure 4a is a graph showing the nitrate nitrogen concentration change of the raw water and treated water according to the operating time in the experimental example according to the present invention.

Figure 4b is a graph showing the pH change of raw water and treated water according to the operating time in the experimental example according to the present invention.

Figure 4c is a graph showing the sulfate ion concentration change of the raw water and treated water according to the operating time in the experimental example according to the present invention.

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

32,232: Raw water pump 34,234: Raw water supply line

42, 242: inflow weir 44, 244: outflow weir

50, 250: sulfur denitrification tank 52, 252: plate-shaped media

54, 254 support means 56 partition wall

58, 258: floating ball 60, 260: post aeration reactor

62, 262: diffuser 64, 264: air pump

66, 266: air supply line 68, 268: outlet

100, 200: denitrification device 240: inflow channel

246: runoff

 [Industrial use]

The present invention relates to a denitrification apparatus in which sulfur is immobilized on a porous plate-like medium and mounted on a sulfur denitrification reactor, and a denitrification process using the same.

The present invention is for effluent water discharged through biological treatment in public sewage treatment plants or factory wastewater treatment plants, etc., to further reduce the nitrogen concentration to meet water quality standards or for use in process water, cleaning water, landscaping water, and toilet washing water. It is applied to reuse, and furthermore, it can be additionally applied to treatment facilities such as leachate, livestock wastewater, etc., where the concentration of nitrogen is relatively high compared to the concentration of organic matter introduced.

 [Private Technology]

Nitrogen present in water is a major component that causes eutrophication with phosphorus and should be removed to below natural concentrations and discharged to the natural world.

Nitrogen removal technology relies entirely on biological treatment, and several biological advanced treatment processes have already been developed, constructed and operated to modify the traditional activated sludge process to achieve higher nitrogen removal rates. However, in the case of treating wastewater containing some large amount of nitrogen, an additional method of adding an external carbon source has been proposed to increase the denitrification efficiency.

The wastewater of the sewage water which has been normally treated by the biologically advanced treatment process conventionally used contains about 10 to 30 mg / L of nitrogen on average, and most of the nitrogen is in the form of nitrate nitrogen.

The nitrogen content contained in the effluent is a value that satisfactorily satisfies the total nitrogen regulation value of 60 mg / L or less currently applied to the public sewage treatment plant in Korea, but is not suitable for reuse of the denitrified effluent for other uses. Typically, the denitrified effluent can be reused as landscaping water, but when used as landscaping water, excessive green algae may be generated to harm the aesthetics and may lead to various complaints.

Therefore, a more efficient denitrification process is needed in order to reuse the denitrified effluent and to prepare for the stricter regulation of effluent nitrogen in the future.

As an alternative process, denitrification using autotrophic bacteria using sulfur, which does not require the supply of an external carbon source, has been studied by many researchers, and there are some practical and field applications.

For example, a packed-bed reactor is implemented in which particulate sulfur is packed into a denitrification reactor and raw water is injected upwards or downwards to allow sulfur oxidative autotrophs to adhere and grow on the surface of particulate sulfur to remove nitrate nitrogen. It became.

The sulfur charged in the packed reactor is mainly used in the form of spherical particles, the size of most of which has a particle size of 2 ~ 7 mm, and the average size of the sulfur even in the bulk of the sulfur, the average size does not exceed 8 mm Do not. This is because industrial use, which consumes large amounts of sulfur in general, requires sulfur in the state of small particle size. Since there is a problem that needs to be processed, most of the existing denitrification processes have used small-size sulfur particles.

Since the spherical particulate sulfur is small in size, the porosity of the filter bed is very small when filled in the packed reactor, and the value is about 30 to 40% on average. In this state, when the denitrification reaction by the sulfur particles proceeds, the growth of the sulfur oxidative autotrophic bacteria and the generation of nitrogen bubbles occur, and the pore portion through which the raw water to be treated and the denitrified treated water can pass becomes smaller. Thus, as the reaction proceeds and the microorganism proliferates, the hydraulic resistance increases, and eventually, a local occlusion occurs, and thus, the mass transfer of nitrate nitrogen is not smooth.

In order to solve this problem, the conventional process introduces a periodic backwashing to periodically detach the microorganisms attached to the filter medium (attached growth). In addition, in order to reduce the amount of backwash water used to suppress the cost increase due to backwashing and to enhance the effectiveness of backwashing, a method of improving turbulence by introducing air with backwashing during backwashing has been proposed. .

This backwashing method causes temporary and repetitive deterioration of activity by periodically applying instant aerobic conditions to the denitrifying bacteria expressed in anoxic conditions, and a large amount of independent nutrients with very slow growth rate are washed out every backwash. It was difficult to continuously secure denitrification bacteria in the reactor.

In particular, upflow or downflow packed reactors must have a minimum two-layer structure for water collection or drainage, and a backwash tank, backwash pump, and piping are required for backwashing. Higher construction costs are required compared to Continuous Stirred Tank Reactor (CSTR). Moreover, there is an additional problem of having to deal with backwash water, accompanied by a problem in that additional power costs are consumed to perform backwash.

In addition to the above-described problems, the denitrification process using granular sulfur as it is due to the fact that sulfur is consumed by the denitrification process as time passes after the initial sulfur particles are filled, and thus the size of the sulfur particles becomes smaller. In particular, the smaller the size and pore size of the particles constituting the filter, the greater the size of the hydraulic resistance passing through the filter, and thus, more frequent backwashing should be performed, thereby lowering the denitrification efficiency. As a result, when the flow rate is the same, the residence time actually passing through the filter bed is lowered, and there is a possibility that the lower perforated plate is blocked in the downflow type.

An object of the present invention for solving the above problems is to provide a denitrification apparatus and a denitrification process using a sulfur denitrification reaction tank having the sulfur-fixed plate-like medium is fixed at a uniform interval, and repeatedly mounted thereon.

In order to achieve the above object, the present invention

Introducing nitrogen-containing raw water into a sulfur denitrification reactor,

Performing autotrophic denitrification using sulfur oxidative autotrophic bacteria in the sulfur denitrification reactor;

Transferring the treated water denitrified in the sulfur denitrification tank to a post-aeration reactor;

Performing a post-treatment process by an acid pipe in the post-aeration reactor;

It provides a denitrification process comprising the step of releasing the treated water.

In addition, the present invention provides a denitrification apparatus for denitrifying raw water containing nitrogen in an autotrophic way by sulfur,

The denitrification apparatus is a denitrification apparatus including at least one sulfur denitrification reaction tank in which a unit structure in which sulfur-immobilized plate media is immobilized at uniform intervals, and wherein the plate media is positioned in a direction perpendicular to the surface of water. To provide.

Preferably, the sulfur denitrification reaction tank is provided with an inlet and outlet weir so as to distribute the inflow and outflow structure evenly on the front surface in order to solve the ubiquitous flow of water by the plate media.

In addition, the denitrification reaction tank is arranged in front of the surface of the water (floating ball) to block the inflow of oxygen and sunlight from the water surface.

The denitrification apparatus is further connected to the sulfur denitrification reaction tank, and further includes a post aeration reaction tank equipped with an acid pipe at the bottom.

Preferably, the plate-like mediators fix sulfur by heating sulfur above a predetermined temperature, and then applying sulfur in a molten state to the porous plate form and cooling it.

Hereinafter, the present invention will be described with reference to the drawings.

1 is a process chart showing a denitrification process using a denitrification apparatus according to the present invention.

Referring to FIG. 1, the denitrification process of the present invention first introduces nitrogen-containing raw water (or wastewater) to be treated into a sulfur denitrification reactor (S1).

At this time, since the raw water is already undergoing biological nitrification process, most of the nitrogen components present are nitrate nitrogen, and since the nitrification consumes a considerable amount of alkalinity, the raw water is introduced in a low alkalinity state. Therefore, since alkali oxidation is also consumed in sulfur oxidative denitrification, most existing processes use a method of supplying alkalinity before entering the reactor or filling a chemical that continuously supplies alkalinity into the reactor. However, even if the alkalinity is low, the pH value of the influent raw water is controlled to meet the discharge standard, and although the pH is decreased during the sulphation denitrification process, it is not a level that seriously inhibits the activity of sulfur oxide microorganisms. In the present invention, unless the pH and alkalinity are abnormally low, alkali is not additionally added to the influent raw water or the alkali feed material such as limestone or shell is not filled in the reactor.

Generally, lime or shell materials filled with sulfur in the reactor to supply continuous alkalinity are sufficiently dissolved at the beginning of the injection and serve to supply alkalinity, but after a certain time, the ability to supply alkalinity is remarkably high. Is reduced. Furthermore, the impurities contained in the surface of the sulfur particles or the generated sulfate ions and dissolved calcium ions form calcium sulfate to cover the surface of the alkali control capacity is lost. Therefore, it is necessary to additionally add a predetermined amount periodically, since there is no function of discharging the sulfur particles having lost the activity that is already filled, there is a problem that the sulfur denitrification reaction tank is more and more unnecessary alkali supplements. Therefore, in the present invention, after the reaction is finished, dissolved oxygen is supplied from the post-aeration reactor, the odor is removed, and the pH is adjusted and discharged.

Subsequently, the raw water introduced into the sulfur denitrification tank removes nitrogen in the raw water through an autotrophic denitrification process by sulfur oxidation autotrophic bacteria under anoxic conditions (S2). That is, as will be described later, the raw water introduced into the sulfur denitrification tank is denitrified by the sulfur oxidative autotrophic bacteria that adhere to and grow on the surface of the plate media while the sulfur provided in the sulfur denitrification tank is fixed.

The autotrophic denitrification reaction carried out in the sulfur denitrification reactor is as described in Scheme 1 below.

As shown in Scheme 1, autotrophic denitrification proceeds under anoxic conditions, and nitrate nitrogen (NO ₃ ⁻ ) is reduced on the surface of the plate-shaped media on which sulfur is immobilized to generate nitrogen gas (N ₂ ), and at the same time sulfur ( S) is oxidized to sulfate ions (SO ₄ ^2- ).

Sulfur oxidation autotrophic bacteria applied to the sulfur denitrification process are typically Thiobacillus Denitrificans , Thiomicrospira Denitrificans , Thiobacillus Versutus , and Thiobacillus Tie. Thiobacillus Thyasiris , Thiosphaera Pantotropha and Paracoccus Denitrificans .

These autotrophs are known to oxidize sulfur (S) and various types of sulfur compounds to sulfate ions (SO ₄ ^2- ) while simultaneously reducing nitrate nitrogen to nitrogen gas. And no external carbon source such as acetate, and economical and effective denitrification can be achieved by the input of cheap sulfur.

As the denitrification process proceeds, the growth of sulfur oxidative autotrophic bacteria proceeds on the surface of the plate media on which sulfur is immobilized, and as the growth proceeds, the thickness of the biofilm by the sulfur oxidative autotrophic bacteria increases. As a result, the mass transfer required in the denitrification process is deteriorated, so that the anaerobic inside of the biofilm proceeds and some biofilms are stripped, and then the biofilm growth is repeated again.

Subsequently, the treated water denitrated in the sulfur denitrification reactor is introduced into the post-aeration reactor (S3).

The post-aeration reactor includes an acid pipe at the bottom of the reactor to supply dissolved oxygen through an appropriate aeration and to remove odors by oxidizing hydrogen sulfide (H ₂ S) that may occur due to the implementation of local anaerobic conditions. In addition, a pH adjuster for adjusting the pH of the treated water and chemical injection and agitation for the post-treatment process is carried out.

Next, the treated water which has been treated in the post-aeration reactor is discharged to the outside (S4), and used for the purpose of reuse or chlorine treatment if necessary. At this time, the treated water flowing to the outside has not only removed much of the nitrate nitrogen contained in the raw water, but also has a considerably lower biochemical oxygen demand (BOD) value. In addition, the removal rate of nitrate nitrogen and biochemical oxygen demand (BOD) is determined by factors such as contamination of raw water, residence time of sulfuric acid reaction tank, inflow temperature of raw water, and the like.

Hereinafter, the denitrification apparatus for carrying out the denitrification process using sulfur according to the present invention will be described in more detail.

2a schematically illustrates the denitrification apparatus of the present invention.

Referring to Figure 2a, the denitrification apparatus 100 of the present invention is provided with a raw water pump 32 for quantitatively injecting raw water,

It is connected to the raw water supply line 34 connected to the raw water pump 32, and is provided with a sulfur denitrification reactor 50 in which the denitrification process is performed,

After aeration reactor 60 is provided for the post-treatment of the treated water treated in the sulfur denitrification reactor 50,

An air pump 64 and an air supply line 66 for injecting air into the post treatment reactor 60 are provided.

The sulfur denitrification reactor 50 is a reactor for removing nitrogen contained in raw water by performing autotrophic denitrification using sulfur oxidative autotrophs.

As described above, in the process using the conventional packed reactor, the biofilm continuously grows on the surface of the granular sulfur during the denitrification process, and as the nitrogen gas generated in the denitrification process rises, it inhibits mass transfer during the denitrification process. In addition, the hydraulic resistance imparted to the raw water and the denitrified treated water flowing into the sulfur denitrification reactor 50 is increased.

Thus, in the present invention, the sulfur in which the biofilm grows is immobilized on the plate filter medium 52, nitrogen gas floats between the plate filter medium 52, and precipitation of the stripped bio film proceeds without any resistance. As a result, it is possible to prevent the denitrification efficiency from being deteriorated due to the deterioration of mass transfer on the surface of the biofilm without additional operation such as backwashing.

FIG. 2B is a diagram showing a plate-like media 52 on which sulfur is immobilized, which is used in the sulfur denitrification reactor 50 of FIG. 2A.

Referring to FIG. 2B, the plate-like mediator 52 in which sulfur is immobilized is mounted at a uniform interval on the support means 54 in the form of a frame manufactured separately, and the size and number 52a of the plate-shaped media 52 according to raw water throughput. , 52b .... 52n).

At this time, the sulfur-fixed plate-like media 52 is deposited by the support means 54 so as to be located in a direction perpendicular to the water surface of the sulfur denitrification tank 50, the flow of raw water introduced into the sulfur denitrification reactor 50 Between the plate media (52) is to be guided naturally in the direction perpendicular to the surface of the plate media (52).

Plate-like media 52 for immobilizing sulfur is preferably a porous plate-like material of a certain thickness or less having excellent water permeability and a large surface area, and the most preferable representative example is a non-woven fabric made of polyester or a material For example, a composite material based on at least one polymer selected from the group consisting of polystyrene, polyurethane, polypropylene, polyethylene, and polyethylene terephthalate may be used. foamed plate) is one of the types selected from the group consisting of.

The method of immobilizing sulfur with respect to the plate-shaped media 52 is not particularly limited in the present invention. However, the sulfur in the molten state obtained by heating above a predetermined temperature is applied or deposited on a plate-shaped media having a predetermined size and then cooled.

When the denitrification process is performed by using the plate-like mediator 52 of which the sulfur of the present invention is immobilized, the unit structure of the plate-shaped mediar 52 mounted in the sulfur denitrification reaction tank 50 is sequentially sequentially depleted by the denitrification process. By replacing the structure with a new plate-shaped media 52 is installed, as well as minimizing the deterioration of the denitrification efficiency, the maintenance is also very easy. This replacement cycle can be estimated simply from the rate of nitrate nitrogen removal and treatment flow in the denitrification reactor.

The sulfur denitrification reaction tank 50 can be manufactured in various sizes and shapes according to the use purpose and purpose, and as shown in FIG. 2A, a separation wall 56 is mounted inside the sulfur denitrification reaction tank 50 so as to provide a multi-stage reaction tank. It is possible to configure.

In addition, the sulfur denitrification reaction tank 50 according to the present invention evenly the inlet and outlet portions of the sulfur denitrification reaction tank 50 in order to eliminate the ubiquitous raw and treated water by the mounting of the plate-like media (52). An inlet weir 42 and an outlet weir 44 are installed to distribute.

At this time, the shape and size of the inlet and outlet weir 42, 44 is appropriately installed and adjusted by those skilled in the art in consideration of the size of the sulfur denitrification reactor 50 and the flow rate of the raw water.

In addition, the sulfur denitrification reaction tank 50 of the present invention is to carry out autotrophic denitrification under an oxygen-free atmosphere, and should suppress the oxygen inflow through the water surface of the reaction tank, which is another inhibitor of denitrification. Oxygen introduced during the autotrophic denitrification process increases the dissolved oxygen concentration in the sulfur denitrification reactor 50 and acts as a deterrent to the denitrification process and accelerates the sulfur oxidation process using dissolved oxygen to consume sulfur without removing nitrogen. .

Accordingly, the denitrification efficiency is maximized by floating the floating ball 58 to block the inflow of oxygen to the water surface of the sulfur denitrification tank 50 and to inhibit the growth of the algae by preventing the irradiation of sunlight. can do.

The denitrification treated water passing through the sulfur denitrification reactor 50 is introduced into the post-aeration reactor 60 through the outlet weir 44 of the sulfur denitrification reactor 50.

The post-aeration reactor 60 may be provided with an diffuser 62 at the bottom of the reactor to supply appropriate air. This air supply is made via the air supply line 66 by placing the air pump 64 on one side of the post-pox reactor 60. As a result, dissolved oxygen may be supplied to the treated water denitrified in the sulfur denitrification tank 50, and the hydrogen sulfide (H ₂ S), which is a result of locally generated anaerobic oxidation, may be oxidized to remove odors.

In addition, a pH adjuster for adjusting the pH of the treated water introduced into the post-aeration reactor 60 and a chemical input and agitation for the post-treatment process are performed.

The post-treated treated water is discharged to the outside through the outlet 68 of the post-aeration reactor 60 is reused.

Therefore, by using the plate-shaped media in which sulfur is immobilized by the present invention, various problems caused by using conventional granular sulfur can be solved. The sulfur-fixed plate media has a higher porosity than that of the granular sulfur, and the denitrification apparatus employing the nitrogen gas is floated between the plate media and the hydraulic resistance is not increased, and backwashing is unnecessary, thereby reducing manufacturing costs.

The denitrification apparatus of the present invention further reduces the nitrogen concentration to meet the water quality standards for biologically treated water in public sewage treatment plants or factory wastewater treatment plants, or meets water quality standards, process water, cleaning water, toilet washing water, landscape water, etc. It can be suitably applied to the treatment of leachate, livestock wastewater, etc., which is difficult to completely remove nitrogen because the concentration of nitrogen is relatively high compared to the concentration of incoming carbon source.

Hereinafter, the present invention will be described in more detail based on the following examples.

<Example 1>

A: Denitrification apparatus SET-UP

A denitrification apparatus 200 constituting the process as shown in FIG. 3 was manufactured.

First, a sulfur denitrification reactor 250 having a width × length × height of 200 × 300 × 1000 mm and a post-aeration reactor 260 having 100 × 300 × 1000 mm were produced using acrylic. The sulfur denitrification reactor 250 constitutes an inlet weir 242 on the front surface, and the raw water transferred through the raw water supply line 234 to the metering pump 232 passes through the inlet water tank 240 to the sulfur denitrification reactor 250. ) Evenly distributed on the front.

Subsequently, in order to fabricate the plate-shaped media 252 in which sulfur is immobilized, molten sulfur was applied and cooled on a non-woven fabric having a thickness of 5 mm, and then each was cut to a size of 190 x 900 mm in width x length. The produced plate-shaped media 252 was manufactured in the vertical direction so as to maintain a gap of 20 mm by making a frame with the support means 254.

An intermediate reservoir 246 is installed at the rear end of the sulfur denitrification reactor 250, and the denitrification treated water passing through the sulfur denitrification reactor 250 passes under the intermediate reservoir 246, so that an outlet weir above the intermediate reservoir 246 ( 244) was transferred to the post-aeration reactor (260). At this time, the intermediate reservoir 246 serves to prevent the floating ball 258 floating on the water surface of the treated water collection and sulfur denitrification reactor 250 for analysis.

The post-aeration reaction tank 260 connected to the sulfur denitrification reactor 250 includes an acid pipe 262, proceeds to aeration through the air pump 264, and raises the dissolved oxygen of the denitrification water to increase the outlet 268. To be discharged through.

B: denitrification process

Sulfur-induced autotrophic bacteria and sequestration growth on the surface of the plate media were induced for a period of time in the sewage treatment plant, and then a certain amount of nitrate nitrogen was added to the raw water (effluent) of the treatment plant.

The raw water to which the nitrate nitrogen was added was injected into the denitrification apparatus of step A. At this time, the residence time in each reactor was 1.5 hours based on the operating volume of the denitrification reactor, the inflow flow rate was 36 L / hr, the denitrification effect was measured for 40 days, and the temperature of the sulfur denitrification reactor was maintained at 10 to 20 ° C.

Experimental Example Measurement of Denitrification Effect

A: denitrification rate

In order to determine the denitrification effect of the denitrification apparatus according to the present invention, raw water and treated water were collected during the experiment period, and the denitrification reaction rate was measured by the following Equation 1 [Koenig, A. and Liu, LH (2001) Kinetic model of autotrophic denitrification in sulphur packed-bed reactors . Wat. Re s. Vol . 35, No 8, 1969-1978].

In the above equation,

k _{(1/2) v} is the denitrification rate constant per unit reactor volume,

C _ef is the effluent substrate conc. Of effluent treated water,

C _in is the influent nitrogen concentration (inffluent substrate conc.) Of the incoming raw water,

Q is the flow rate of raw water through the reactor,

A is the cross section of the reactor,

H is the height of the reactor.

Equation 1 refers to a half-order bulk reaction in a steady-state condition by sulfur oxidation independent nutrients in a packed reactor.

The denitrification rate constant in the Example according to the present invention was calculated using Equation 1, and compared with the denitrification rate constant in the denitrification reactor using granular sulfur of various sizes described in the literature as shown in Table 1 below. .

Yellow star Sulfur Particle Size (mm) k _{(1/2) v} (mg ^1/2 / L ^1/2 min) (x 10 ^-3 ) Temperature (℃) Example Plate media - 12.7-29.6 10 to 20 Comparative Example 1 ¹⁾ Granular sulfur 2.8 to 5.6 49-60 20-25 Comparative Example 2 ²⁾ Granular sulfur 5.6-11.2 24.8 to 34 20-25 Comparative Example 3 ³⁾ Granular sulfur 11.2-16 18.7-22.3 20-25 Comparative Example 4 ⁴⁾ Granular sulfur 2.8 to 5.6 39.3 to 58.7 20-25 1), 2), 3) Source: Koenig, A. and Liu, LH (2001) Kinetic model of autotrophic denitrification in sulphur packed-bed reactors . Wat. Res . Vol . 35, No 8, 1969-1978 4): Koenig, A. and Liu, LH (1997)

As shown in Table 1, the denitrification reaction of the embodiment of the present invention showed similar results to the denitrification rate constant of the reactor using granular sulfur having a size of about 11.2 to 16 mm in Comparative Example 3. Although the denitrification process using the denitrification apparatus using the plate-like media on which the sulfur is immobilized according to the present invention has a relatively lower biofilm surface area than the denitrification process using the conventional granular sulfur, the denitrification efficiency due to the material transfer efficiency is lowered. This means minimizing the reduction and ultimately maximizing the denitrification efficiency per unit biofilm surface area.

In addition, when the denitrification rate constant is higher, it means a faster denitrification effect, the denitrification effect of the embodiment of the present invention is compared to the comparative examples 1 to 2 to 4 applied to the granular sulfur of the smaller size than the granular sulfur applied in Comparative Example 3 Showed low results.

However, the results of the comparative examples are all obtained while maintaining the conditions (alkalinity, temperature, pH, etc.) in which the denitrification reaction can be performed as effectively as possible using synthetic wastewater in the laboratory, and is particularly applicable in the commercial sulfur denitrification process. Since the backwashing process is excluded, considering the fact that there is room for sufficiently increasing the density of sulfur when producing the plate media of the present invention showing a relatively low sulfur density, the denitrification apparatus using the sulfur-fixed plate media is used. It can be seen that the denitrification process is very efficient.

B: denitrification effect

In order to determine the denitrification effect of the denitrification apparatus according to the present invention, raw water and treated water were collected during the experimental period, and the nitrate nitrogen concentration, pH and sulfate ion concentration were measured and shown in FIGS. 4A to 4C.

Figure 4a is a graph measuring the change in the nitrate nitrogen concentration of the raw water and treated water according to the operating time, Figure 4b is a graph measuring the change in the pH of the raw water and treated water, Figure 4c is a sulfate of raw water and treated water It is a graph measuring the change of ion concentration.

Referring to FIG. 4A, as a result of comparing the nitric acid concentration between the raw water (-●-) flowing into the sulfur denitrification tank and the denitrification treated water (-○-) obtained after the denitrification process, it was 10 to 50 during the operation period of about 40 days. It was found that about 5 to 10 mg-N / L of nitrate nitrogen was removed from the influent water having a nitrate nitrogen concentration of about mg-N / L.

Referring to FIG. 4B, the raw water (-●-) flowing into the sulfur denitrification reactor exhibited a pH of about 7 and decreased slightly after the denitrification process, but the denitrified water (-○-) was 6.5 or more. pH was shown. These results indicate that even if the autotrophic denitrification reaction by sulfur in the sulfur denitrification reaction tank of the present invention does not show acidity, the denitrification reaction can be sufficiently performed without supplying an alkalinity.

Referring to Figure 4c, the concentration of sulfate contained in the raw water (-●-) and the denitrification water (-○-) flowing into the sulfur denitrification tank was higher in the denitrification water. These results show that autotrophic denitrification by sulfur is effectively performed in the sulfur denitrification reactor.

As described above, the present invention devises a denitrification apparatus using a sulfur oxidizing autotrophic bacterium comprising a reaction tank equipped with a unit structure in which sulfur-immobilized plate media is arranged at uniform intervals, and denitrification of raw water using the same. It showed a high denitrification reaction rate at a relatively low temperature.

The denitrification apparatus according to the present invention was able to effectively remove nitrogen contained in the wastewater by performing autotrophic denitrification by using sulfur-fixed plate media. This method of the present invention does not require a separate carbon source and does not require backwashing, thereby simplifying installation and reducing costs.

Claims (12)

Introducing nitrogen-containing raw water into a sulfur denitrification reactor, Performing an autotrophic denitrification process using sulfur oxide autotrophic bacteria in the sulfur denitrification reactor; Transferring the treated water denitrified in the sulfur denitrification tank to a post-aeration reactor; Performing a post-treatment process by an acid pipe in the post-aeration reactor; A denitrification process comprising the step of releasing the treated water. The denitrification process according to claim 1, wherein the autotrophic denitrification process is performed under anoxic conditions. In the denitrification apparatus for denitrifying raw water containing nitrogen in an autotrophic way by sulfur, The denitrification apparatus is a denitrification apparatus comprising at least one sulfur denitrification reactor in which the unit structure in which the sulfur-immobilized plate media is immobilized at uniform intervals, and the plate media is positioned in a direction perpendicular to the water surface. The denitrification apparatus according to claim 3, wherein the plate-shaped media is produced by heating sulfur at a predetermined temperature or more, and then cooling the sulfur in a molten state by coating or depositing the plate-shaped media. The denitrification apparatus according to claim 3, wherein the plate-shaped media is a porous plate-shaped material. The denitrification apparatus according to claim 5, wherein the porous plate-like material comprises at least one polymer selected from the group consisting of polyester, polystyrene, polyurethane, polypropylene, polyethylene, and polyethylene terephthalate. The method of claim 5, wherein the porous plate-shaped material is made of one type selected from the group consisting of non-woven fabric (woven fabric), woven fabric (woven fabric), mesh (mesh) and foamed plate (foamed plate) Denitrification apparatus characterized by .. 4. The denitrification apparatus according to claim 3, wherein the plate-shaped media is fixed by supporting means to form a unit structure. The denitrification apparatus according to claim 3, wherein the sulfur denitrification reaction tank has an inlet weir on one side into which the raw water is introduced and an outlet weir on one side of the outflow. 4. The denitrification apparatus according to claim 3, wherein the sulfur denitrification reactor arranges a floating ball over the entire surface of the trademark surface. The denitrification apparatus according to claim 3, wherein the denitrification apparatus is further connected to the sulfur denitrification reaction tank, and further includes a post-aeration reaction tank equipped with an acid pipe at a lower portion thereof. The denitrification apparatus according to claim 11, wherein the post-aeration reactor comprises an acid pipe.

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