KR100661625B1 - Denitration apparatus for the wastewater having the nitrogenous compound - Google Patents

Abstract

The present invention introduces a neutralization tank (10) for neutralizing nitrogen compound wastewater, wastewater discharged from the neutralization tank (10), and organic wastewater, thereby consuming microorganisms by consuming organic matter contained in the wastewater under aerobic conditions. In addition, the logarithmic growth tank 20 for nitrifying the nitrogen compounds contained in the wastewater, the denitrification tank 30 for denitrifying the nitrified nitrogen compounds in the logarithmic growth tank 20, and the wastewater discharged from the denitrification tank 30. Aeration tank 40 to aeration, sedimentation tank 50 for precipitating and purifying the wastewater discharged from the aeration tank 40, and sludge precipitated in the sedimentation tank 50 organic acid fermentation, and the resulting organic acid is denitrification tank 30 It comprises an anaerobic organic acid fermentation tank (70) for supplying, and the sludge discharged from the settling tank (50) between the sedimentation tank (50), the logarithmic growth tank (20) and the aeration tank (40) the logarithmic growth tank 20 Provides an apparatus for removing total nitrogen in waste water nitrogen compound, it characterized in that the sludge return line 58 is returned to the aeration tank 40 is provided. In addition, the organic wastewater is mixed with the nitrogenous wastewater, and the mixed wastewater is subjected to a wastewater treatment step including a denitrification step, and the sludge produced through the wastewater treatment step is anaerobic organic acid fermentation to generate an organic acid and the organic acid is Provided is a total nitrogen removal method of the nitrogen compound waste water, characterized in that supplied to the denitrification step to use as an organic carbon source for denitrification.

Description

Total Nitrogen Removal System for Nitrogen Compound Wastewater {DENITRATION APPARATUS FOR THE WASTEWATER HAVING THE NITROGENOUS COMPOUND}             

1 is a view schematically showing the configuration of a total nitrogen removal apparatus for nitrogen compound wastewater according to a preferred embodiment of the present invention.

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

10: neutralization tank 15: pH sensor

17: Acid / Alkali Supply Department 20: Log Growth Tank

22: filter 30: denitrification tank

35: dissolved oxygen meter 37: nitric acid supply unit

40: aeration tank 50: sedimentation tank

58: sludge conveying line 60: sludge concentration tank

67: coagulant supply unit 68: upper water conveying line

70: anaerobic organic acid fermentation tank 72: crusher

77: sugar supply

The present invention relates to a total nitrogen removal device and a method for removing nitrogenous waste water, and more particularly, to achieve total nitrogen removal at low cost and high efficiency, and to remove and remove nitrogen nitrogen wastewater from a nitrogen compound wastewater. It is about.

The Ministry of Environment is expanding the applicable area of the emission allowance standard for total nitrogen and total phosphorus, which is a source of eutrophication and green algae, such as rivers and lakes, to fertilizer manufacturing, chemical manufacturing, food and beverage manufacturing, metal processing, etc. Most wastewater dischargers operating in the country are mandatory to install and operate individual nitrogen and phosphorus treatment facilities.

However, there are many technical and financial problems in installing treatment facilities for each emitter, and due to the enormous investment and operating costs, it is a very heavy burden especially for small and medium sized industrial plants.

Process wastewater discharged from fertilizer manufacturing, chemical manufacturing, metalworking and semiconductor processing is discharged with little or no organic content. On the other hand, in these processes, a large amount of nitric acid or ammonia is used alone or in a mixture for cleaning or etching and is generated as wastewater.

Conventionally, a nitrogen compound process wastewater containing such nitrogen compounds (nitric acid, ammonia, etc.) is introduced into a wastewater treatment process for living sewage in a state of being mixed with domestic sewage during the collection process and is treated.

In other words, the activated sludge and influent are directly mixed in the anaerobic state, and dissolved nitrogen in the influent is used as a carbon source for denitrification to remove total nitrogen.

However, this method is used to denitrify ammonia nitrogen or nitrate nitrogen generated from low concentrations of ammonia or protein contained in domestic wastewater, and fertilizer manufacturing process, chemical manufacturing process, There is an inadequate supply of carbon sources for the denitrification of total nitrogen in process wastewaters from metal processing and semiconductor processes.

Therefore, conventionally, as a solution, alcohols that are easily decomposed, such as methanol, are added as an organic carbon source to remove total nitrogen.

However, methanol and acetic acid supplied here are regulated under the Toxic Substances Control Act, and are subject to licensing and permitting risks of safety accidents such as toxicity and fire. In addition, there is a problem of an increase in operating costs due to methanol or acetic acid costs.

The present invention has been made to solve the above problems, the present invention is low or no use of organic matter, while ammonia and nitric acid use is enormous in terms of environmental, economic and time in the total nitrogen removal device of a large amount of nitrogen compounds wastewater. It is an object of the present invention to provide a total nitrogen removal apparatus and method capable of maximizing the total nitrogen removal efficiency at a low cost by avoiding the conventional method accompanying the problem.

In addition, the present invention improves the ease of operation and management by removing the risk of safety accidents, such as toxic and fire, and provides a total nitrogen removal device and method that can be installed and operated without limitation of various regulatory laws, such as the toxic substances law, firefighting law. The purpose is to.

It is also an object of the present invention to provide a total nitrogen removal apparatus and method capable of minimizing the amount of waste sludge generated from domestic wastewater.

It is also an object of the present invention to provide a total nitrogen removal apparatus and method capable of preventing secondary pollution due to waste sludge, minimizing odor generation and providing a sanitary treatment environment.

It is also an object of the present invention to provide a total nitrogen removal apparatus and method capable of achieving a reduction in site area.

In order to achieve the above object, the present invention includes a neutralization tank for neutralizing the nitrogen compound wastewater containing nitrogen compounds, the organic wastewater containing the wastewater discharged from the neutralization tank and organic matter is included in the wastewater under aerobic conditions A logarithmic growth tank that grows microorganisms by consuming organic matter and nitrifies nitrogen compounds contained in wastewater, a denitrification tank that denitrates nitrified nitrogen compounds from the logarithmic growth tank, and aeration of wastewater discharged from the denitrification tank And an anaerobic organic acid fermentation tank for fermenting sludge precipitated in the sedimentation tank, organic acid fermentation, and supplying the generated organic acid to the denitrification tank. Between the log growth tank and the aeration tank is discharged from the settling tank Logarithmic growth above the sludge tank, and provides an apparatus for removing total nitrogen in waste water, characterized in that the nitrogen-containing compound having a sludge return line for returning to the aeration tank.

The present invention, anaerobic organic acid fermentation of sludge, glucose, food waste, and other organics generated from organic wastewater such as domestic sewage or manure to remove the total nitrogen of the nitric acid / ammonia process wastewater to obtain the organic acid and use it as an organic carbon source To denitrify the process wastewater.

Preferably, the neutralization tank has a pH sensor and an acid / alkali supply, the pH sensor measures the pH of the wastewater in the neutralization tank, and the acid / alkali supply is in the neutralization tank measured by the pH sensor. Acid or alkali is fed to the neutralization tank depending on the pH of the wastewater.

Preferably, the apparatus further includes a filter and a crusher, wherein the filter is configured to filter the organic wastewater prior to flowing into the logarithmic growth tank so that only filtered water is introduced into the logarithmic growth tank, and the crusher is organic solids and the organic wastewater. After crushing the filter residue of the anaerobic organic acid fermentation tank is transferred.

Preferably, the settling tank conveys 10 to 20% of the sludge precipitated to the logarithmic growth tank through the sludge conveying line, and 20 to 30% of the precipitated sludge to the aeration tank.

Preferably, the inclined plate settling tank is used alone as the settling tank, or the inclined plate settling tank is used in parallel with the immersion type membrane separation device at the outlet.

Preferably, a sludge concentration tank is provided between the sedimentation tank and the anaerobic organic acid fermentation tank, and between the sludge concentration tank and the sedimentation tank is provided with a supernatant water conveying line for conveying the supernatant water of the sludge concentration tank to the sedimentation tank. A coagulant supply unit is provided, and the coagulant supply unit agglomerates by supplying a coagulant to the returned supernatant water, and the precipitation tank precipitates it.

Preferably, of the sludge conveyed to the anaerobic organic acid fermentation tank side, part of the sludge is disposed after dehydration treatment, and the rest is configured to flow into the anaerobic organic acid fermentation tank.

Preferably, the anaerobic organic acid fermentation tank is operated at a residence time of 3-7 days, pH 3.5-4.5, temperature 10-35 ° C. and a concentration of volatile organic acid of 2,000 mg / l or more.

Preferably, the denitrification tank has a dissolved oxygen meter and a nitric acid supply unit, the anaerobic organic acid fermentation tank has a sugar supply unit, and the dissolved oxygen meter measures the dissolved oxygen of the waste water in the denitrification tank, and the dissolved oxygen meter The nitric acid supply unit supplies nitric acid to the denitrification tank when the amount of dissolved oxygen in the denitrification tank is less than the set value, and the saccharide supply unit is supplied to the anaerobic organic acid fermentation tank when the amount of dissolved oxygen in the denitrification tank exceeds the set value. Feed the sugars.

In addition, the present invention is a method for removing the total nitrogen of the nitrogen compound wastewater containing nitrogen compounds, mixing the organic wastewater containing organic matter with the nitrogen compound wastewater, and the wastewater treatment step including the denitrification step Anaerobic organic acid fermentation of sludge produced through the wastewater treatment step to produce an organic acid and supplying the organic acid to the denitrification step to use as an organic carbon source for denitrification, the total nitrogen removal method of the nitrogen compound wastewater to provide.

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

1 is a view schematically showing a total nitrogen removal apparatus of nitrogen compound wastewater according to a preferred embodiment of the present invention.

As shown, the total nitrogen removal device of Figure 1 is neutralized tank 10, logarithmic growth tank 20, denitrification tank 30, aeration tank 40, sedimentation tank 50, sludge concentration tank 60 and anaerobic organic acid It comprises a fermentation tank (70).

Chinese tank (10)

Nitrogen wastewater discharged from the process is separated from the wastewater of other components and flows into the process wastewater collection tank (not shown). If organic process wastewater is present, the organic process wastewater is also introduced into the sump.

The separated and collected process wastewater is supplied to the nitrogen compound neutralization tank 10 at a constant flow rate by the pump 11. The neutralization tank 10 performs a function of neutralizing nitrogen compound wastewater.

The nitrogen compound neutralization tank 10 includes a stirrer 13, a pH sensor 15, and an acid / alkali supply unit 17. The pH sensor 15 performs a function of measuring the pH of the wastewater in the neutralization tank 10. The acid / alkali supply unit 17 functions to neutralize the wastewater by supplying acid or alkali to the neutralization tank 10 according to the pH of the wastewater in the neutralization tank 10.

Algebraic Growth Tank (20)

The filtered water obtained by filtering the organic wastewater (wastewater containing organic matter, such as domestic wastewater, manure, etc.) with the screen filter 22 together with the wastewater transferred from the nitrogen compound neutralization tank 10 flows into the logarithmic growth tank 20. Further, activated sludge conveyed from the settling tank 50 through the sludge conveying line 58 flows into the logarithmic growth tank 20.

The logarithmic growth tank 20 consumes organic matter contained in the wastewater under aerobic conditions to grow the microorganisms in logarithmic scale and nitrifies the nitrogen compound contained in the wastewater.

Aerobic microorganisms and nitrates contained in the activated sludge returned from the settling tank 50 will act as an important microorganism in the active logarithmic growth tank (20).

HeterotropHic bacteria use organic matter as a carbon source for energy and cell synthesis, while autotrophic bacteria use inorganic carbon to obtain carbon and oxidize minerals to obtain energy.

The organic wastewater and the polymer organic matter contained in the process wastewater are decomposed into low molecular soluble organic matter by the aerobic microorganisms returned from the settling tank 50.

The microorganisms contained in the activated sludge returned from the settling tank 50 grow rapidly by using soluble organic matter as the organic carbon source.

When the amount of organic matter is sufficient compared to microorganisms, microorganisms are in logarithmic growth phase, and bacteria, fungi and free-staying protozoa dominate. These microorganisms have high energy levels, which actively absorb soluble organics to proliferate cells and do not disperse and aggregate. Therefore, it is very weak even if there is no precipitation at all.

In logarithmic growth tanks, proteins contained in organic wastewater are hydrolyzed and dissociated into ammonia nitrogen (NH ₃ -N) via amino acids, and nitrite nitrogen (NO ₂ -N) and nitrate nitrogen (NO ₃ -N).

Nitrogen Process The ammonia in the wastewater is nitrite nitrogen (NO ₂ -N) by nitrate microorganisms (Nitrosomonas, Nitrosococcus) and oxidized to nitrate nitrogen (NO ₃ -N) by another nitrobacter Nitrocystis. Nitric acid bacteria, which oxidize ammonia to nitrite and nitrite to nitric acid, respectively, are actively active, and denitrogen bacteria are slowed.

The active logarithmic growth tank 20 is provided with an diffuser or aeration machine 26 for aeration of blower blower air in water. The wastewater in the logarithmic growth tank 20 is mixed by the diffuser or aeration machine 26 and stays for about 10 to 12 hours.

The wastewater of the active logarithmic growth tank 20 is transferred to the high concentration denitrification tank 30 uniformly by the pump 21 for 24 hours.

Denitrification tank (30)

In the high concentration denitrification tank 30, the wastewater transferred from the active logarithmic growth tank 20 and the organic acid produced in the anaerobic organic acid fermentation tank 70 are mixed. The high concentration denitrification tank 30 consumes the organic acid produced in the anaerobic organic acid fermentation tank 70 as an organic carbon source by introducing the organic matter in the organic wastewater into an empty nutrition state through an active logarithmic growth step.

In an enclosed high concentration denitrification tank 30, the anaerobic anaerobic bacteria group breathes and consumes oxygen in nitrate nitrogen or nitrite nitrogen to convert nitrate nitrogen into nitrogen gas and at the same time consumes organic matter to form cellular tissues. .

The denitrification tank 30 is designed to allow the wastewater to stay in a closed state for 24 hours in a sealed state that completely blocks air and debt. The high concentration denitrification tank 30 is provided with a stirrer 33 or an underwater mixer, a nitric acid supply unit 37, and a dissolved oxygen meter 35 to prevent precipitation.

The wastewater transferred from the active logarithmic growth tank 20 and the organic acid produced in the anaerobic organic acid fermentation tank 70 are stirred with a stirrer 33 or a water mixer to quickly reduce the dissolved oxygen concentration.

In order to maintain a constant denitrification efficiency, it is important to constantly supply the organic acid generated in the anaerobic organic fermentation tank 70, for this purpose it is necessary to supply a constant sludge to the anaerobic organic fermentation tank 70 for 24 hours.

Nitrogen process wastewater generation When the nitrogen compound is insufficient due to the shutdown of the process and the concentration of organic matter is high, the organic matter is converted to anaerobic state and odor is generated. Therefore, the nitric acid supply unit 37 is provided to prevent this. Keep constant

When the dissolved oxygen amount measured by the dissolved oxygen meter 35 installed in the high concentration denitrification tank 30 is less than the set value, the nitric acid supply unit supplies nitric acid to the denitrification tank 30, and the dissolved oxygen amount exceeds the set value. When, the sugar supply unit installed in the anaerobic organic acid fermentation tank 70 supplies sugars such as glucose, fructose and maltose to the anaerobic organic acid fermentation tank 70.

As nitrate nitrogen or nitrite nitrogen is used as a hydrogen acceptor, the nitrate nitrogen is converted into nitrogen gas and released into the atmosphere by the anaerobic anaerobic bacterial reaction in a closed high concentration denitrification tank 30 which completely blocks air and debt.

Denitrifying bacteria are heterotrophs and require dissolved organic materials as electron donors as energy sources and as carbon sources for the synthesis of cellular materials. Wastewater from semiconductor, plating, steel, and chemical processes supplies methanol as an organic carbon source because of the high total nitrogen concentrations and generally the lack of organics. The amount of methanol supplied is calculated by adding 2.47 products of nitrate nitrogen, 1.53 products of nitrous nitrogen and 0.87 products of dissolved oxygen.

However, in the present invention, by using the anaerobic organic acid fermentation sludge generated from organic wastewater such as domestic wastewater without using methanol to obtain the organic acid and supplying it to the organic carbon source required for denitrification, the toxic substances management method, fire method, etc. Total nitrogen can be removed at low cost without restriction.

In addition, even when the sludge generated from the organic wastewater is inadequate, an organic acid is produced by supplying a saccharide to the anaerobic organic acid fermentation tank 70 without supplying methanol to the denitrification tank 30, and using it as an organic carbon source when denitrification.

When the saccharide is directly added to the high concentration denitrification tank 30, the amount of dissolved oxygen in the high concentration denitrification tank 30 is increased by oxygen included in the sugar molecules, thereby preventing the denitrification efficiency from dropping.

Preferably, the concentration of mixed liquid suspended solids (MLSS) of the wastewater in the denitrification tank 30 is maintained at 5000 mg / l or more, and the dissolved oxygen concentration is maintained at 0.1 mg / l or less.

The wastewater discharged from the high concentration denitrification tank 30 contains organic substances that are difficult to degrade, and are transported naturally to the active aeration tank 40 with little dissolved organic matter and dissolved oxygen required as a nutrient supply source for microorganisms.

Aeration tank (40)

In the aeration tank 40, the microorganisms are converted to the reduced growth phase by becoming a vacant nutrient state in which the quantity of microorganisms is high and the nutrients are low.

The sludge which has progressed to the endogenous growth phase of the cells through the reduced growth phase has a strong adsorption power, and has a great ability to adsorb and oxidize suspended matter, colloidal material and soluble materials in sewage in a short time, and also has good precipitation property. Such sludge is called activated sludge. Microorganisms in activated sludge coexist with heterotrophic bacteria that oxidize and reduce organic substances to obtain basic energy for survival and independent nutrient bacteria that oxidize and obtain inorganic energy.

In the aeration tank 40, adherent organisms such as bacteria, ciliary insects, flagella worms, nematodes, and rotifers predominate. The energy levels of these microorganisms are considerably lowered so that when they come into contact with each other, they coagulate and become very sticky.

Heterotrophic bacteria and other microorganisms, dissolved particulates, etc. gather together to form activated sludge flocs, and dissolved organics, organic colloids and suspended particles are adsorbed on the solid-liquid interface of the activated sludge flocs. At this time, the larger the interface between the floc and the wastewater, and the larger the difference in organic concentration between the interfaces, the greater the efficiency.

Organics adsorbed on the surface of the floc are degraded by enzymes, some of which are synthesized into cells, and the remainder is released back into the water in the form of oxidized minerals. Because of this continuation of metabolism, a constant contact reaction is maintained at the interface between the mucosa or floc and the wastewater.

The adsorption force of the floc of activated sludge is very strong and is in equilibrium in 20 minutes to 1 hour. Organics adsorbed on the flocs of activated sludge synthesize new cells by catabolism and assimilation of aerobic microorganisms.

The active aeration tank 40 includes an diffuser or aeration machine 46 and a dissolved oxygen meter 45.

The aeration tank 40 is designed as an open tank having a residence time of about 3 to 5 hours.

The operation of the aeration tank 40 should maintain conditions for the ratio of organic matter and microbial mass (F / M), nutrients, toxic substances, and the like. Preferably, the organic matter: nitrogen: phosphorus ratio is 100: 5: 1, and the dissolved solids concentration is 5000 mg / l or more, dissolved oxygen level of 0.5 ppm or more, pH 6-8, temperature 15-35 ℃.

Sedimentation Tank (50)

The activated sludge floc generated in the active aeration tank 40 is transferred to the settling tank 50, and the settling tank 50 removes suspended solids, that is, sedimentary solids, having a specific gravity greater than water, by gravity.

Conventionally, a general sedimentation tank and an inclined plate sedimentation tank are used, and the supernatant is discharged after removing the pin floc through a chemical treatment process or an advanced treatment process and disinfecting, and the precipitated activated sludge is 20 to 30% as an active aeration tank 40. 70 to 80% of the remaining excess sludge was returned after dehydration and discarded.

In the present invention, preferably, the inclined plate settling tank is used alone, or the inclined plate settling tank is used in parallel with the immersion type membrane separator. In addition, about 10 to 20% of the activated sludge precipitated by the pump 51 is returned to the active logarithmic growth tank 20, and 20 to 30% is returned to the active aeration tank 40, and the remaining excess sludge is returned to the sludge concentration tank 60. Transfer.

Sludge Concentration (60)

The sludge concentration tank 60 concentrates the precipitated sludge and transfers the concentrated sludge to the anaerobic organic acid fermentation tank 70 at a constant flow rate by the pump 61.

The supernatant of the sludge concentration tank 60 is returned to the settling tank 50 through the supernatant conveying line 68.

The supernatant conveying line 68 is provided with a flocculant supply part 67. In the supernatant of the sludge concentration tank 60, there is a pin floc in which organic matter is oxidized and floated in an inorganic state. The flocculant supply unit 67 supplies a flocculant to the pin floc and aggregates it by the line mixer 69. The aggregated pin floc is returned to the settling tank 50 for settling.

The sludge thickening tank 60 is provided with a concentrated sludge conveying pump 61 for uniformly transferring a predetermined amount of the concentrated sludge. The sludge thickening tank 60 is transferred to an anaerobic organic acid fermentation tank 70 to make organic acid constant and denitrate the organic acid produced at a high concentration. To be sent to Joe (30).

When living sewage is used as organic wastewater flowing into the logarithmic growth tank 20, the sludge of the sludge concentration tank 60 is anaerobic organic acid fermentation tank (70) in a state of 2 to 5% solids concentration (60 to 80% organic matter in solids). Is put into. When manure is used as the organic wastewater flowing into the logarithmic growth tank 20, it is injected into the anaerobic organic acid fermentation tank 70 at a solid concentration of 2.5 to 3.5% (BOD 10,000 to 14,000 ppm).

Excess sludge discharged from the settling tank 50 is transferred to the sludge thickening tank 60, and concentrated to the anaerobic organic acid fermentation tank 70 to increase the sludge concentration is used to produce an organic acid, compared to the conventional activated sludge method The sludge generation rate is reduced to 30-40%.

In order to control the concentration of inorganic sludge, a portion of the concentrated sludge is dewatered and then disposed of. Inorganic sludge is produced in the process of autotrophic bacteria in the logarithmic growth tank 20 and the aeration tank 40 using inorganic carbon to obtain carbon and oxidizing the inorganic material to obtain energy.

Anaerobic Organic Acid Fermentation Tank (70)

The sludge concentrated in the sludge concentration tank 60 is transferred to the anaerobic organic acid fermentation tank 70. In addition, the organic matter collected by the screen filter 22, organic solids such as food waste, such as garbage collected and collected by the crusher 72, and then introduced into the anaerobic organic acid fermentation tank (70).

The anaerobic organic acid fermentation tank 70 performs organic acid fermentation of such sludge, food waste, and other organic substances, and supplies the generated organic acid to the denitrification tank 30.

In the anaerobic organic acid fermentation tank (70), the polymer material introduced in the form of microbial cells and complex polymers in the anaerobic state is decomposed into soluble organic substances by extracellular enzymes released by microorganisms such as organic acid bacteria, so that the low molecular form or simple structure A hydrolysis step of converting to a material and an organic acid generating step of generating an organic acid from a low molecular weight material hydrolyzed by organic acid bacteria are performed.

In the anaerobic state, insoluble organic substances such as carbohydrates, fats and proteins, and microbial keratin are hydrolyzed into glucose or other monosaccharides which are soluble organic substances in series by extracellular enzymes released by microorganisms. In the hydrolysis step, a chain reaction occurs by enzymes secreted from several microorganisms, respectively.

In the case of cellulose (Cellulose) is mainly introduced in the form of complex polymers, such as fibril, semi-fiber component, such polymer material must be dissolved in water and decomposed into low molecular material before it can be finally metabolized by the cell. Cellulose is broken down into glucose by hydrolysis, and the degraded glucose or other monosaccharides is taken up by the cells.

Hydrolyzed organic matter is decomposed to lower organic acids via higher fatty acids by organic producing bacteria. In this case, various substances such as fatty acids, aldehydes, alcohols, carbon dioxide, and hydrogen are produced.

Anaerobic microorganisms can be divided into aerobic bacteria group (organic acid bacteria) and absolute anaerobic bacteria group (methane bacteria), but the microorganisms involved in acid production in the anaerobic organic acid fermentation tank (70) are organic acid bacteria of the anaerobic bacteria group, Clostridium formicoaceticum, Clostridium thermoaceticum, Clostridium propionicum, Clostridium butyricum, Ruminocuccus flavefaciens, Bacteroides succinogenes, Selnomonas ruminantium Acetobacterium woodii, Propionibacterium arabinosum, Sarcina maxima Butyribaterium methylotropusicium, etc.

Anaerobic organic acid fermentation tank 70 has a configuration of a closed tank that can stay for 7 days in a state of completely blocking the air and debt. The anaerobic organic acid fermentation tank 70 includes a stirrer or an underwater mixer 73, a pH sensor 75, and a sugar supply unit 77.

The anaerobic organic acid fermentation tank 70 grows only organic acid bacteria in order to generate organic acids and supply them to the organic carbon source of the denitration process performed in the high concentration denitrification tank 30. The anaerobic organic acid fermentation tank 70 operates at concentrations of 3 to 7 days, pH 3.5 to 4.5, medium to low temperatures (10 to 35 ° C.), and volatile organic acids of 2,000 mg / l or more. It does not multiply.

The concentration of the volatile organic acid produced in the anaerobic organic acid fermentation tank 70 is 2,000 mg / ℓ or more accumulates volatile organic acid, the pH is lowered. Methane is a slow growth rate and sensitive to conditions such as temperature, pH, toxic substances, etc., by limiting the methane bacteria growth environment by the concentration of volatile organic acid in the anaerobic organic acid fermentation tank (70) to enable continuous organic acid production.

In general, anaerobic digestion is slower in reaction rate than aerobic digestion and therefore requires an enlargement of the apparatus. Anaerobic digestion takes about 20 to 120 days. However, in the present invention, the volatile organic acid produced in the anaerobic organic fermentation tank 70 softens the form of the sludge complex polymer and promotes the reaction rate to ferment the anaerobic organic acid. The time was dramatically reduced to 3-7 days. Through this, the size of the anaerobic organic acid fermentation tank 70 was reduced to about 1/30 of the capacity of the general anaerobic digestion tank, thereby realizing the miniaturization of the apparatus.

In addition, in the present invention, by introducing the concentrated sludge into the anaerobic organic acid fermentation tank 70, the amount of waste sludge can be reduced to about 1/10.

In addition, by using low-temperature bacteria (PsychropHilic bacteria) and mesophilic bacteria (mesopHilic bacteria) as organic acid bacteria can be operated without a separate heating device.

According to the above configuration, the use of ammonia and nitric acid is low or no use of organic matter, while in the total nitrogen removal device of a large amount of nitrogenous waste water, the conventional method that entails enormous problems in terms of environmental, economic and time, By using organic acid as a carbon source by producing organic acid from waste sludge of domestic sewage without using methanol, total nitrogen removal efficiency can be maximized at low cost.

In addition, by eliminating the risk of safety accidents such as toxic and fire, it is easy to operate and manage, and it is possible to install and operate without restriction of various regulatory laws such as toxic substance law, firefighting law.

In addition, by transporting most of the concentrated sludge to the anaerobic organic acid fermentation tank to be used for organic acid generation to minimize the amount of waste sludge generated during the treatment of wastewater, such as domestic sewage, it is possible to achieve the minimization of the treated site.

In addition, by discharging the sludge converted to inorganic, it is possible to prevent secondary contamination to prevent the occurrence of odor and to provide a sanitary treatment environment.

In addition, the size of the anaerobic organic acid fermentation tank can be reduced to about 1/30 as compared with the conventional anaerobic digestion tank by reducing the anaerobic organic acid fermentation time and increasing the fermentation efficiency.

Also, as anaerobic organic acid bacteria. The use of low temperature (10-35 ° C) bacteria eliminates the need for additional heat sources, further achieving cost savings.

Claims (10)

Neutralization tank to neutralize nitrogen compound wastewater containing nitrogen compound, A logarithmic growth tank which inflows wastewater discharged from the neutralization tank and organic matter containing organic matter, consumes organic matter contained in the wastewater under aerobic conditions to grow microorganisms and nitrifies nitrogen compounds contained in the wastewater. , Denitrification tank for denitrifying the nitrified nitrogen compound in the logarithmic growth tank, An aeration tank for aeration of the wastewater discharged from the denitrification tank; A sedimentation tank for precipitating and purifying the wastewater discharged from the aeration tank, and Organic acid fermentation of sludge precipitated in the precipitation tank, and comprises an anaerobic organic acid fermentation tank for supplying the resulting organic acid to the denitrification tank, And a sludge conveying line for returning sludge discharged from the settling tank to the logarithmic growth tank and the aeration tank between the settling tank, the log growth tank and the aeration tank. The method of claim 1, Additionally provided with a filter and a crusher, The filter, the organic wastewater is filtered before entering the logarithmic growth tank so that only the filtered water is introduced into the logarithmic growth tank, The shredder is a total nitrogen removal device for nitrogen compound wastewater, characterized in that the organic solids and the organic waste water filtration wastes are broken up and transferred to the anaerobic organic acid fermentation tank. The method according to claim 1 or 2, The neutralization tank has a pH sensor and an acid / alkali supply portion, The pH sensor measures the pH of the waste water in the neutralization tank, And the acid / alkali supply unit supplies acid or alkali to the neutralization tank according to the pH of the wastewater in the neutralization tank measured by the pH sensor. The method according to claim 1 or 2, The sedimentation tank, via the sludge conveying line, the 10-20% of the sludge is precipitated to the log growth tank, the 20-30% of the precipitated sludge is returned to the aeration tank. Nitrogen removal device. The method according to claim 1 or 2, Using the inclined plate sedimentation tank alone as the settling tank, or using the inclined plate sedimentation tank in the inlet to the immersion type membrane separation device in combination with the nitrogen compound waste water total nitrogen removal device. The method according to claim 1 or 2, A sludge concentration tank is provided between the precipitation tank and the anaerobic organic acid fermentation tank, Between the sludge concentration tank and the settling tank is provided with a supernatant water conveying line for returning the supernatant water of the sludge concentration tank to the settling tank, The supernatant conveying line is provided with a flocculant supply unit, The flocculant supply unit aggregates by supplying a flocculant to the returned supernatant, and the precipitation tank precipitates it. The method according to claim 1 or 2, Part of the sludge conveyed to the anaerobic organic acid fermentation tank side, part of which is discarded after the dehydration treatment, only the remainder is introduced to the anaerobic organic acid fermentation tank total nitrogen removal apparatus of the nitrogen compound wastewater. The method according to claim 1 or 2, The anaerobic organic acid fermentation tank has a residence time of 3 to 7 days, pH 3.5 ~ 4.5, temperature 10 ~ 35 ℃ and volatile organic acid concentration of more than 2,000mg / L, characterized in that the total nitrogen removal device of waste nitrogen. The method according to claim 1 or 2, The denitrification tank is provided with a dissolved oxygen meter and a nitric acid supply unit, The anaerobic organic acid fermentation tank has a sugar supply unit, The dissolved oxygen meter measures the dissolved oxygen of the wastewater in the denitrification tank, When the amount of dissolved oxygen in the denitrification tank measured by the dissolved oxygen meter is less than a set value, the nitric acid supply part supplies nitric acid to the denitrification tank, and when the amount of dissolved oxygen in the denitrification tank exceeds the set value, the sugar supply part is Total nitrogen removal apparatus for nitrogen compound wastewater, characterized in that the supply of sugar to the anaerobic organic acid fermentation tank. A method for removing total nitrogen from nitrogen compound wastewater containing nitrogen compounds, Neutralizing the nitrogenous waste water; By mixing the nitrogen compound wastewater neutralized in the neutralization step and the organic wastewater containing the organic matter, consuming organic matter contained in the wastewater under aerobic conditions to increase the number of microorganisms and nitrify the nitrogen compound contained in the wastewater Logarithmic growth phase; A denitrification step of denitrifying the nitrified nitrogen compound in the logarithmic growth step; An aeration step of aeration of the wastewater which has undergone the denitrification step; A precipitation step of precipitating and purifying the wastewater passed through the aeration step, and returning some of the precipitated sludge to the log growth step and the aeration step; Part of the sludge precipitated in the precipitation step, the organic acid fermentation, and the anaerobic organic acid fermentation step of supplying the generated organic acid to the denitrification step, the total nitrogen removal method of the nitrogen compound wastewater characterized in that it comprises.

Images