KR100823318B1 - Denitrification process and producing method of the pellet for sulfur oxidation denitrification of nitrate and nitrite - Google Patents

Abstract

A carrier for sulfur oxidizing denitrification of nitrate and nitrite is provided to remove nitrogen contained in sewage and wastewater having a low C/N ratio without addition of an organic carbon source such as methanol by improving a sulfur oxidizing denitrification carrier for using microorganisms having a function of oxidizing and denitrifying sulfur at the same time, and a method for preparing the carrier, a method for seeding microorganisms into the carrier, and a method for denitrification of wastewater using the carrier are provided. A carrier for sulfur oxidizing denitrification is prepared by injecting water into the composition and mixing water with the composition after preparing a composition comprising, by weight percent, 70 to 10% of at least one selected from alkaline materials such as sulfur(S^0), calcium carbonate(CaCO3), magnesium oxide(MgO), dolomite(CaMg(CO3)2), and magnesite(MgCO3), 5 to 10% of ocher, and 5 to 10% of an acrylate-modified ethylene vinyl acetate copolymer resin that is biodegradable and hydrophilic. A method for preparing a carrier for sulfur oxidizing denitrification comprises: preparing a composition comprising, by weight percent, 70 to 10% of at least one selected from alkaline materials such as sulfur(S^0), calcium carbonate(CaCO3), magnesium oxide(MgO), dolomite(CaMg(CO3)2), and magnesite(MgCO3), 5 to 10% of ocher, and 5 to 10% of an acrylate-modified ethylene vinyl acetate copolymer resin that is biodegradable and hydrophilic, injecting water into the composition, and homogeneously mixing water with the composition to a rotation speed of 400 to 1,000 rpm; discharging a mixture through a discharge port formed in a side face of a mixer, injecting the mixture into a molding machine to continuously mold the mixture into carriers with a constant shape; drying the molded carriers at a temperature of 100 to 105 deg.C in a dryer for 12 to 24 hours, and cooling the dried carriers using natural wind; and sorting the carriers per sizes using a sorter.

Description

Sulfuric acid denitrification carrier of nitric acid and nitrite nitrogen, method for preparing the same, method for planting microorganisms thereof, and method for denitrification of wastewater using the same

The present invention relates to a denitrification carrier for removing nitrogen by denitrifying nitrogen and nitrite nitrogen contained in water and wastewater with nitrogen gas, and a nitrate nitrogen and nitrite nitrogen for carrying out nitrogen removal by filling such a carrier. The present invention relates to a carrier for sulfate denitrification, a method for preparing the same, a method for seeding microorganisms thereof, and a method for denitrification of wastewater using the same, and more particularly, for the use of a microorganism having a function of oxidizing and denitrating sulfur. Nitrogen nitrogen and nitrite properties to remove nitrogen from wastewater, sewage, and wastewater with low C / N ratio without adding organic carbon sources such as methanol. Carbosulfide denitrification carrier, preparation method thereof, microbial planting method and wastewater denitrification method using the same will be.

In general, the most widely used method for removing nitrogen contained in wastewater is biological nitrogen removal by nitrification and denitrification using heterotrophic microorganisms.

Ammonia nitrogen (NH ₄ ⁺ -N) is converted to nitrite nitrogen (NO ₂ ^-- N) or nitrate nitrogen (NO ₃ ^-- N) by autotrophic microorganisms, from ammonia nitrogen to nitrite nitrogen when oxidized, and the microorganism such as Nitrosomonas, Nitrosococcus, Nitrosobacillus engaged, when it is oxidized to nitrate-nitrogen in the nitrite is involved such as Nitrobacter, Nitrosocystis.

However, the rate of proliferation of autotrophic microorganisms is much slower than that of heterotrophs, and the microbial growth rate is low.

With Nitrosomonas Nitrobacter cell production rate was 0.15mg-cell / mg-NH ₄ ⁺ -N, 0.02mg-cell / mg-NO ₂ ^-- N, and oxygen consumption rate was 3.22mg -O ₂ / mg-NH ₄ ⁺ -N, 1.11 The reduction in mg-O ₂ / mg-NO ₂ ^-- N and alkalinity is 7.14mg -Alkalinity / mg-NH ₄ ⁺ -N. In other words, the nitrification reaction requires oxygen, and a large amount of nitrification bacteria must be secured and maintained in the reaction tank.

In addition, a large amount of alkalinity is required, so a pH buffer is required to control the lowering pH. Temperature, BOD / TKN ratio, and ammonia nitrogen concentration also affect nitrification.

Denitrification is carried out by heterotrophic microorganisms such as Pseudomonas , Bacillus, and Micrococcus in the absence of dissolved oxygen (DO) and in the presence of nitrate nitrogen or nitrite nitrogen (anoxic condition). Refers to the process of converting nitrogen to nitrogen gas (N ₂ ). Denitrification consists of the conversion of nitrate nitrogen to nitrite nitrogen and the conversion of nitrite nitrogen to N ₂ gas via NO and N ₂ O.

Denitrification produces an alkalinity of 2.3-3.0 mg as CaCO ₃ / mg-N. In a system that simultaneously performs nitrification and denitrification, the alkalinity lowered in nitrification can be increased to some extent.

However, conventional denitrification using heterotrophic microorganisms requires an organic carbon source as an electron donor.

At present, the most common nitrogen removal method is circulating nitrification and denitrification using suspended activated sludge. This method consists of an anaerobic tank and an aerobic tank. By circulating the waste water, denitrification in the anoxic tank and nitrification occur in the aerobic tank.

However, this method requires a separate installation of the reaction tank, so a large installation site is required and the aerobic capacity must be increased.

In order to obtain stable treated water with a small reaction tank volume, a method of filling activated sludge or a carrier immobilized with nitrifying or denitrifying bacteria is used instead of suspending activated sludge. However, there is a disadvantage that the carrier cost is high.

    As a method of nitrifying and denitrifying in a single bath, there is a batch activated sludge process (SBR process). This process is a variation of the activated sludge method, and five processes of [inflow-reaction-precipitation-discharge-atmosphere] are sequentially performed in one reactor, and in the precipitation process, aeration is stopped to form an oxygen-free tank to perform denitrification.

This process has the advantage of a simple device, easy maintenance and low installation and operating costs. However, scum is easy to accumulate in the reactor and a discharge device of supernatant is required.

In addition, if any of the above-described methods are wastewater having a high nitrogen concentration and a low organic matter concentration, that is, a low C / N ratio, much energy is required for oxygen supply for nitrification, and an electron donor must be added for denitrification. do.

The most commonly used is methanol. However, in the case of methanol addition, it is difficult to control the proper amount of addition and methanol should not remain in the treated water due to the toxicity of methanol itself.

It is known that the amount of methanol requires more than three times the amount of nitrogen to be treated. However, the maintenance cost cannot be ignored because it is actually required 5 to 10 times depending on the type of wastewater and the wastewater phase.

A new technique that supplements the above disadvantages is the denitrification using sulfur.

Denitrification using sulfur, Thiobacillus The sulfated microorganisms represented by denitrificans as a final receptor NO ₂ ^-, NO ₃ ^-, a denitrification takes place, using the NO, N ₂ O.

The final product of the sulfated denitrification is SO ₄ ^{2 -} in O _2, NO ₂ ^-, NO ₃ ^-, NO, N ₂ O is, but using as the final hydrogen acceptor of sulfation, as the final hydrogen acceptor NO ₂ ^- or NO ₃ ^Since O ₂ is more preferred, desulfurization and denitrification can only be expected in an oxygen-free state where no O ₂ is present and NO ₂ ^- or NO ₃ ^- is present.

T. denitrificans is an absolute chemical autotrophic microorganisms ^{_{CO 2, HCO 3 -, CO}} 3 2 - and grow using inorganic carbon such as a carbon source. The sulfation of the ^{T. denitrificans S O, S 2-,} S 2 O 3 2 -, S 4 O 6 2 -, SO 3 2 - is a high denitrification efficiencies are low oxidation state sulfur compounds so used as a hydrogen donor.

In the sulfate denitrification by T. denitrificans , the cost of sulfur compound as a hydrogen acceptor is compared with the chemical cost per electron equivalent, and it is reported that S ^O is the most economic hydrogen donor (Bisogni, JJr & Driscoll, CT Jr. Denitrification using thiosulfate and sulfide, J. Environ. Eng. Div. Proc. ASCE, Vol. 103, p. 593-604 (1977)).

S ^O has the advantages of abundant resources, low cost, easy storage, good handling and no toxicity, but it does not dissolve easily in water.

Sulfation denitrification microorganisms are known to be difficult to accumulate and solid-liquid separation of microorganisms due to their cohesiveness. (Biotecro noroji- 活用 の 高 機能 型 活性 汚泥 法) In addition, there is a problem that SO ₄ ^{2 −, which} is the final product of the sulfated reaction, lowers the pH.

Domestic denitrification techniques include biofilm filtration sewage treatment technology using flocculation sedimentation and granular conditions, alkalinity addition type sewage and wastewater treatment technology using sulfur denitrification, and SPAD method. These processes are similar in terms of using sulfur but are different. Biofilm filtration sewage treatment technology using flocculation sedimentation and granular conditions, wastewater flows down-current into an oxygen-free reaction tank filled with granular conditions (S ^o ), and a part of alkali consumed during denitrification reaction. In order to supplement this, a fixed amount of sodium carbonate (Na ₂ CO ₃ ) is added to the pipe where the treated water of the biofilm filtration (nitrification tank) is transferred to the granular denitrification tank to be mixed by Line Mixing. It is said to be put into interlocking operation with.

In the case of advanced alkaline treatment of sewage and wastewater using the denitrification process, wastewater is introduced into the denitrification tank filled with granular conditions (S ^o ) by up-current, and a part of alkali consumed during denitrification reaction. In order to compensate for this problem, an alkaline material filling tank is installed to fill carbonic acid-based alkali material including limestone, clam shell, oyster shell, egg shell, dolomite, magnesium carbonate, etc. do.

The two methods are used to inject alkaline materials from the outside, and in the case of the SPAD method, methanol is added to the sulfur contact tank filled with granular and limestone layers without introducing alkaline materials from the outside. It is a method to use nutrient denitrification at the same time.

Japanese Patent Application No. Hei 4-9119 using sulfur is a technique for removing nitrogen and phosphorus in wastewater at the same time and desulfurization by adding sulfur to the existing aerobic-anaerobic activated sludge process.

The above-mentioned denitrification methods destroy alkalinity during denitrification of the conventional denitrification method, and especially in the case of wastewater containing high concentration of nitrate nitrogen and low alkalinity, the pH is lowered so that denitrification does not proceed anymore. In this case, a method of adding an alkalinity substance, adding a small amount of methanol, or filling with sulfur in a reactor is adopted.

However, since only sulfur exists inside the reactor when the alkali material or methanol is added from the outside, it is difficult to retain the denitrifying bacteria during the initial application. When the alkalinity is low, the denitrification is not possible and the pH is lowered as the amount of SO ₄ ^{2 -} is increased. Denitrification is difficult when denitrification no longer progresses or when the concentration of nitrate or nitrite is high.

And when the ratio of the alkalinity and sulfur dissolution is not matched, Ca 2+ in the alkalinity material reacts with SO ₄ ^{2 -} generated by oxidation of sulfur to form gypsum (CaSO ₄ ), which sinks to the bottom and hardens the inflow. .

In Japanese Patent Laid-Open No. 2002-66592 published recently, a method of producing particles by pressing a denitrification agent by mixing sulfur and limestone has been proposed.

This method can be molded batchwise and continuously, resulting in high production efficiency. However, when manufacturing only the press, there is a disadvantage in that the bonding strength between the powders are weak and easily dispersed in water and spilled.

It was developed to compensate for the above disadvantages of the sulfidation denitrification carrier, which is an integrated carrier, and a mixture of sulfur and calcium carbonate (S ^o + CaCO ₃ used in the applicant's patent No. 0503134). (Hereinafter referred to as "SC pellet") is a carrier for sulfate denitrification.

SC pellets are prepared by mixing and melting alkaline materials such as sulfur and calcium carbonate in an appropriate ratio to make them homogeneous, and then quenching them in water to form voids while removing carbon dioxide, followed by drying, crushing, and classification. It is.

And there is the carrier of the applicant's patent No. 0448891 which added the function which can remove phosphorus to this SC pellet.

This SC pellet has a very excellent effect compared to the conventional sulfidation denitrification technology using sulfur particles in terms of nitrogen treatment performance, ease of operation, stability of efficiency, and the like.

  However, since the amount of the carrier to be initially charged depends on the nitrogen concentration and the flow rate of the influent, there was a disadvantage in terms of cost in the case of a large capacity and a high concentration.

    In the present invention, the technical problems such as the treatment performance and stability of the above-mentioned desulfurization denitrification carrier, the problem of bonding strength when using a press, and the carriers of the prior patent Nos. 0503134 and 0448891 of the applicant as described above In order to overcome the disadvantages of the large capacity, the increase of the cost at a high concentration, it is to prepare a sulfidation denitrification carrier that can maximize the amount of nitrogen removed per 1kg of the desulfurization denitrification carrier.

That is, when the amount of nitrogen removed per carrier increases, the amount of carrier to be charged can be reduced, so that the cost, installation area and the like can be significantly reduced.

The final object of the present invention is to treat wastewater having a low C / N ratio containing nitrogen nitrate and nitrite nitrogen, that is, wastewater or wastewater treatment having a low organic matter concentration and a relatively high nitrogen concentration (especially nitrogen nitrate or nitrite nitrogen). The organic matter is removed but the nitrogen is hardly removed. For example, livestock wastewater, anaerobic livestock waste, chemical plant wastewater, semiconductor and electronics plant wastewater, plating wastewater, landfill leachate, agricultural drainage, aquaculture wastewater, composting A new concept of high performance sulfate denitrification carriers for the removal of nitrogen from the facility's effluent, food digestion desorption, sewage, village sewage, groundwater contaminated with nitrate nitrogen, methods for its preparation, planting of the microorganisms and denitrification of wastewater using the same It is characterized by providing a treatment method.

Hereinafter, the specific configuration and operation of the present invention will be described with reference to Examples, but the scope of the present invention is not limited only to these Examples and the present invention will be described in detail below.

The carrier for sulfidation denitrification of the present invention is 20 to 70 wt% of sulfur (S ^O ), calcium carbonate (CaCO ₃ ), magnesium oxide (MgO), dolomite (CaMg (CO _{3 ) 2} ), magnesite (MgCO ₃ ) 70-10 wt% of alkaline substances, 5-10 wt% of ocher, and 5-10 wt% of acryl-modified ethylene acetvinyl copolymer resin having hydrophilic properties as biodegradable.

Sulfur is the main component for the desulfurization and denitrification reaction, and alkaline substance is a component for maintaining the neutrality (6 ~ 8) and preventing the lowering of pH generated during the supply of alkalinity and denitrification. Ocher serves to adsorb odor components while providing microelements to microorganisms, and resins act as crosslinks to aggregate carrier components.

Alkaline substances have different proportions and components used depending on the type and nature of the sewage and wastewater to be treated.

In the case of a large amount of calcium in the wastewater to be treated, sulfur and magnesite are the main components, and dolomite and calcium carbonate are added as secondary components depending on the concentrations of nitrate nitrogen and nitrite nitrogen in the wastewater. If the calcium component is small, sulfur and calcium carbonate are the main components, and dolomite and magnesite are added as secondary components. When phosphorus (P) is to be treated together with nitrogen (N), sulfur and calcium carbonate or magnesium oxide are the main components, and magnesite and dolomite are added as secondary components.

Hereinafter, the present invention will be described in detail by way of examples.

Table 1.

Example. For the preparation of the carrier according to the type and properties of sewage and waste water, the composition as shown in Table 1 was prepared by the carrier-1 to the carrier-8 by the method described below.

Carrier-1 Carrier-2 Carrier-3 Carrier-4 Carrier-5 Carrier-6 Carrier-7 Carrier-8 NO ₃ & NO ₂ concentration (mg / L) 400 or less More than 400 Calcium Concentration (mg / L) 200 or less More than 200 200 or less More than 200 Phosphorus removal U radish U radish U radish U radish Sulfur (wt%) 20 30 20 30 40 50 60 70  Alkaline substances Calcium carbonate (wt%) 30 30 15 10 20 20 5 5 Magnesite (wt%) 10 10 30 30 10 5 10 10 Dolomite (wt%) 10 10 15 10 10 5 5 5 Magnesium oxide (wt%) 10 10 10 10 Yellow soil (wt%) 10 10 5 10 5 10 5 5 Acrylic Modified Ethylene Acetic Vinyl Copolymer (wt%) 10 10 5 10 5 10 5 m 5

After adding the raw materials to the mixer by the ratio, 15wt% of water is added to the total weight and mixed homogeneously at 400 ~ 1,000rpm, and the mixed raw materials are discharged through the outlet of the mixer side and put into the pellet molding machine to continuously cylindrical Molding

The molded carrier is dried by drying in a 100 ~ 105 ℃ dryer for 12 to 24 hours and then cooled by natural wind at room temperature, and finished by sorting by size through a 2 ~ 6Φ x 4 ~ 8mm sorting machine.

At this time, the molding machine is not uniformly mixed if the stirring speed is too slow, and only the center part is mixed if it is too fast, and uniform mixing is not performed while the raw material is attached to the wall of the molding machine. The temperature and drying time of the dryer is an optimal condition for meeting the drying and wet hardness standards of the carrier. If the drying temperature is lower than 100 ° C, the drying time should be longer. If the drying temperature is higher than 110 ° C, sulfur, the main raw material, will melt.

In the dryer, the temperature is artificially raised to remove moisture by evaporation, but when dried in the dryer and left at room temperature, some of the unevaporated water is gradually evaporated. In addition, since the temperature of the carrier after drying in the dryer is rather high, natural drying is performed while cooling in a natural wind at room temperature after drying in the dryer.

The carrier prepared by the above-described method should have an apparent specific gravity of 0.7-1.3 g / cm3, a dry hardness of 10 or more after drying, 5.0 or more, and a wet hardness measured and taken out after soaking in water for 1 day. After soaking for 10 days, the measured wet hardness should not be less than 0.8.

The dry hardness should be 5.0 or higher because of the possibility of breakage during packing, transportation and filling, and a certain amount must be slowly eluted while maintaining a constant strength when filled in water.If the wet hardness is lower than the above-mentioned standard, the hardness is constant in water. It is not easy to maintain and breaks due to pressure, and the carrier component must be slowly eluted in water. If the wet hardness is too high, the elution is not smooth and the treatment performance is lowered.

In planting microorganisms, 60 to 70% of the effective volume of the reaction tank is filled with a carrier, 10 to 20% of the sludge of the sewage treatment plant is added to the effective volume, and left to rest for one week, followed by internal circulation for one week, and sulfated. The denitrifying microorganism is attached to the carrier while acclimating.

After acclimation and attachment, the sludge that is suspended is not removed through the outlet of the lower part of the reactor and is removed. Then, the wastewater is continuously introduced and operated.

The carrier for sulfidation and denitrification of the present invention is used as a filling type, and the specific gravity is between 0.7 and 1.3 so that the carrier moves finely by temporarily increasing the flow rate due to internal circulation.

Due to this fine movement, a gas such as nitrogen gas sandwiched between carriers is degassed upward according to the flow of water, and SS such as sludge moves upward or downward depending on the particle size.

This phenomenon facilitates contact between the carrier and the wastewater, which helps to maintain high and stable denitrification performance. Sulfation denitrification microorganisms are independent nutrient microorganisms, and their growth rate is low, so the amount of SS increase is very small.

Therefore, unlike conventional methods using sulfur particles, no backwashing is required.

< Test Example  1> Experiment with synthetic wastewater

After filling eight kinds of carriers in each reactor by 70% of the reactor effective capacity according to Example 1, the concentration of nitrogen nitrate (NO ₃ -N) prepared by adding potassium nitrate (KNO ₃ ) to tap water into the reactor After 90% (v / v) of 200mg / L synthetic wastewater was injected, 10% (v / v) of sludge was planted and left to rest for 1 week, and then internally circulated for 1 week. Sludge precipitated at the bottom of the reactor was discharged through the sludge outlet.

During this period, samples were taken once every two days and analyzed. When more than 90% of nitrate was removed, potassium nitrate was added to obtain a concentration of about 200 mg / L.

After the acclimatization of the microorganisms was completed, a synthetic wastewater with a nitrate nitrogen concentration of 5 mg / L was added to each reactor, and the treated water was analyzed in batch form one day after analysis. It was done once.

After the 5mg / L experiment was completed, the synthetic wastewater with nitrate concentrations of 10, 20, 30, 50, 70, 100, and 120mg / L was sequentially prepared, and the batch experiment was performed in the same manner as the 5mg / L experiment. The results are shown in Table 2.

After the batch test was completed, the denitrification performance was evaluated while continuously introducing synthetic wastewater having nitrate nitrogen concentrations of 100, 300, and 500 mg / L into each reactor.

Table 2. Batch test results using synthetic wastewater (average of five times)

NO ₃ -N concentration (mg / L). Denitrification (mg-NO ₃ -N / kg-Pellet / day) Carrier No. One 2 3 4 5 6 7 8 5 110 112 109 105 110 105 105 100 10 158 156 144 140 147 154 150 142 20 264 259 253 232 240 248 241 234 30 302 301 295 288 275 277 260 256 50 296 294 310 314 292 281 270 263 70 498 500 510 502 512 506 510 505 100 595 595 604 617 610 604 615 618 120 1150 1160 1210 1280 1270 1250 1260 1290

Denitrification Performance As a result of the continuous experiment, the denitrification performance (mg-NO ₃ -N / kg-Pellet / day) is 381mg-NO ₃ -N / kg-Pellet / day, 300mg / L when the nitrate is 100mg / L when one 464mg-NO3-N / kg- Pellet / day, 500mg / day when L _{769mg-NO 3 -N / kg-} Pellet / day was, similarly to the results of the batch experiments the higher of the initial nitrate small farmers even higher tendency (See Table 3).

Table 3. Continuous test results using synthetic wastewater

NO ₃ -N concentration (mg / L) Denitrification (mg-NO ₃ -N / kg-Pellet / day) Carrier No. One 2 3 4 5 6 7 8 100 368 375 365 381 366 365 360 362 300 450 455 450 464 460 460 455 458 500 723 750 754 769 761 782 775 791

The apparent specific gravity of each carrier after the evaluation experiment was completed was 1.03-1.15, and the wet hardness was in the range of 1.09-1.34.

< Test Example  2> livestock wastewater

    Livestock wastewater has a high T-N concentration and high concentrations of calcium and magnesium. Based on the results of Example 1 described above, using the carrier-4, carrier-6, and carrier-8 prepared above was carried out the carrier performance test of the livestock wastewater of pig farms.

The livestock wastewater treatment plant is equipped with a long-term aeration reactor and the nitrogen content of livestock wastewater after long-term aeration is as follows (Table 4).

Table 4. Nitrogenous Components and Concentrations of Livestock Wastewater after Long-term Aeration

ingredient NO ₂ -N NO ₃ -N NH ₄ -N Concentration (mg / L) 287 22 310

Three reactors of the same capacity (A, B, C) were prepared and 70% of the effective volume of the reactor was filled with each carrier (A reactor: carrier-4, B reactor: carrier-6, C reactor: carrier-8). 90% (v / v) of wastewater and 10% (v / v) of sludge are planted and left to rest for 1 week, circulating for 1 week, and then left to rest and discharge all the wastewater and sludge in the reactor through the sludge outlet. I was.

A new wastewater was introduced to investigate the change of nitrogen concentration during the 24 hours under the batch condition. The analysis was stopped when the nitrogen component was 100% removed. The results of the batch experiments are shown in Table 5.

Table 5. Livestock Wastewater Batch Test Results

Reactor A reactor B reactor C reactor ingredient NO ₂ -N NO ₃ -N NO ₂ -N NO ₃ -N NO ₂ -N NO ₃ -N Influent 287 22 287 22 287 22 After politics 249 21 250 21 246 21 2 hours later 224 15 207 12 167 11 8 hours later 208 ND 48 ND 35 ND 12 hours later 125 - ND - ND - 18 hours later 56 - - - - - After 20 hours ND - - - - - 24 hours later - - - - - -

 * ND: Not detected, *-: Not analyzed

In the above results, the denitrification performance of the carrier (mg-NO ₃ -N & NO ₂ -N / kg-Pellet / day), A reaction tank is 446 mg-N / kg-Pellet / day, B reaction tank is 711 mg-N / kg-Pellet / day, C reactor was found to be 738 mg-N / kg-Pellet / day.

In the case of the existing monolithic sulfate denitrification carrier of our company, the denitrification performance of livestock waste water was 200-400 mg-N / kg-Pellet / day.

In the case of general yellow carriers, there is no practical application for the treatment of high concentrations of nitric acid such as livestock wastewater, and laboratory results are known to be 70-170 mg-N / kg-Pellet / day.

< Test Example  3> Semiconductor Wastewater

Semiconductor wastewater releases nitrate nitrogen during product pickling.

Therefore, there are cases where high and low concentrations are separated and treated, and mixed and treated. Therefore, the concentration of nitrate is 50 ~ 1,000mg / L depending on the situation of each plant.

In Experiment 3, low concentration wastewater was tested.

As the carrier, carrier-1 and carrier-2 were used.

Fill the 70% of the effective volume of each reactor with the carrier, add 90% (v / v) of the wastewater, plant the sludge 10% (v / v), let it stand for 1 week, circulate internally for 1 week, and then settle the sludge outlet Through to discharge all the waste water and sludge in the reactor.

Fresh wastewater was introduced and treated continuously.

The total nitrogen (T-N) concentration of the wastewater to be treated was 75mg / L, nitrate nitrogen was 62mg / L and most of the nitrite nitrogen was 10mg / L. The wastewater to be treated was allowed to flow in for one week, followed by continuous operation with a residence time (HRT) of 2 hours and 4 hours.

As a result, 92.53% of the reaction tank D filled with the carrier-1 had an average of 5.6 mg / L of total nitrogen of the treated water at a residence time of 4 hours.

Nitrogen nitrate was 2.5 mg / L, about 95.97% was removed, and nitrous nitrogen was 100%.

Reactor E filled with carrier-2 removed 93.07% of the total treated water nitrogen at an average of 5.2 mg / L at a residence time of 4 hours.

Nitrogen nitrate was 2.6 mg / L and about 95.81% was removed and nitrite nitrogen was 100%.

In the case of Reactor D filled with carrier-1, the total nitrogen of the treated water was removed by 11.2 mg / L on average, and 85.07% was removed by an average of 2 hours, and about nitrate was 9.1 mg / L on average, about 85.32%. Nitrous acid nitrogen was removed 100%.

In the case of Reactor E filled with Carrier-2, total nitrogen of the treated water was removed at an average of 11.5 mg / L and 84.67% at 2 hours of retention time, and about 85.97% of nitrate was removed at an average of 8.7 mg / L. Nitrous acid nitrogen was removed 100%.

In view of the above results, the performance of Carrier-1 and Carrier-2 was not significantly different.

< Test Example  4> sewage

Sewage had a low nitrogen concentration and contained nitrogen and phosphorus, so experiments were carried out using carrier-3.

Fill 70% of the effective volume of the reactor (F) with the carrier, add 90% (v / v) of sewage, and plant the sludge 10% (v / v), let stand for 1 week, circulate internally for 1 week, and then All the sewage and sludge in the reactor were discharged through the sludge outlet. Fresh sewage was introduced and treated continuously.

The total nitrogen (T-N) concentration of the sewage to be treated was 35 mg / L, 23 mg / L of nitrate nitrogen and 8 mg / L of ammonia nitrogen.

The sewage to be treated for 1 week was introduced and allowed to acclimatize, followed by continuous operation with a residence time (HRT) of 2 hours and 4 hours.

As a result, 72.57% of the total nitrogen of the treated water was removed at an average of 9.6 mg / L at the residence time of 2 hours. Nitrate was averaged 1.4 mg / L and 93.91% was removed.

At 1 hour of residence time, the total nitrogen of treated water was 12.5 mg / L on average and 64.29% was removed. On the other hand, the nitric nitrate was 3.1 mg / L on average and 86.52% was removed.

The present invention to solve the problems such as the treatment performance, stability of processing efficiency, cost burden in a large capacity, the production of a monolithic sulfate denitrification carrier that can maximize the amount of nitrogen removed per 1kg of carriers And a method of planting and operating microorganisms. If the amount of nitrogen removed per carrier is increased, the amount of carrier to be charged can be reduced, thereby significantly reducing the cost and installation area.

In the present invention, wastewater containing a low C / N ratio containing nitrate nitrogen and nitrite nitrogen, that is, organic matter in the wastewater or wastewater treatment process having a low organic matter concentration and a relatively high nitrogen concentration (especially nitrogen nitrate or nitrite nitrogen) Is removed but little nitrogen is removed, for example, livestock wastewater from anaerobic processes, chemical plant wastewater, semiconductor and electronics plant wastewater, plating wastewater, landfill leachate, agricultural drainage, aquaculture plant wastewater, and composting wastewater. It is a very useful invention to provide a high performance integrated monosulfide denitrification carrier and a denitrification method using the same for removing nitrogen from food digestion desorbent, sewage, village sewage, groundwater contaminated with nitrate nitrogen, and the like.

Claims (7)

In the carrier for sulfate denitrification, By weight ratio, at least 20 to 70wt% of sulfur (S ^O ), calcium carbonate (CaCO ₃ ), magnesium oxide (MgO), dolomite (CaMg (CO _{3 ) 2} ), magnesite (MgCO ₃ ) Composition 70 ~ 10wt%, ocher 5 ~ 10wt%, biodegradable hydrophilic hydrophilic acrylic modified ethylene acetvinyl copolymer resin 5-10wt% and then mixed with water administration to prepare a desulfurization denitrification carrier . The method according to claim 1, Said alkaline substance is selected according to the type of sewage and waste water to be treated, the properties, the concentration of nitrogen nitrate, nitrite nitrogen to be treated, the concentration of phosphorus and organic matter. In the method for producing a carrier for sulfated denitrification, At least two or more alkaline substances such as sulfur (S ^O ) 20 to 70wt%, calcium carbonate (CaCO ₃ ), magnesium oxide (MgO), dolomite (CaMg (CO _{3 ) 2} ), magnesite (MgCO ₃ ) by weight in the mixer 70 to 10wt%, 5 to 10wt% of ocher, 5 to 10wt% of biodegradable hydrophilic acrylic modified ethylene acetvinyl copolymer resin, and then mixed with water to 400 ~ 1,000rpm, The mixed mixture is discharged through a discharge port on the side of the mixer, put into a molding machine, and continuously formed into a carrier having a predetermined shape. The molded carrier is dried in a dryer at a temperature of 100 ~ 105 ℃ 12 ~ 24 hours and then cooled by natural wind, Method for producing a carrier for sulfate denitrification, characterized in that for producing by selecting the size by the sorting device. The method according to claim 3, The apparent specific gravity of the carrier is 0.7 ~ 1.3 g / cm3, the dry hardness after 10 days after drying is 5.0 or more, soaked in water for 1 day and the measured wet hardness is 1.0 or more, and soaked in water for 10 days The wet hardness measured by taking out is 0.8 or more, The manufacturing method of the carrier for sulphation denitration. Filling the carrier for sulfidation and denitrification of claim 1 with 60 to 70% of the effective volume of the reaction tank, planting sludge corresponding to 10 to 20% of the effective volume, allowing to stand for one week, and then internally circulating for one week. A microorganism seeding method of a carrier for sulfate denitrification, characterized in that the microorganisms are acclimatized. The method according to claim 5, After the acclimation of the microorganisms, microorganisms other than the microorganisms attached to the carrier through the outlet of the lower part of the reaction tank is discharged so that only microorganisms attached to the carrier for the sulfidation denitrification exist in the reaction tank. Planting method. The carrier for the sulfidation and denitrification of claim 1 is used as a filling type, but the flow rate is temporarily increased by internal circulation to move the carrier finely, so that a gas such as nitrogen gas sandwiched between the carriers is changed according to the flow of water. A denitrification treatment method for wastewater, characterized in that the degassing is carried out to the upper part and the SS such as sludge is moved to the upper part or the lower part according to the particle size to make contact with the carrier and the wastewater to perform denitrification.