KR100475840B1 - Compact, flexible and economical nitrogen removal process for municipal and industrial waste water - Google Patents

Abstract

The present invention uses a method of using a thermal hydrolysate by high temperature and high pressure thermal hydrolysis as an external carbon source, and selectively or simultaneously adopting an aerobic deammonium method that can treat a high concentration of nitrogen without external carbon. The present invention proposes a nitrogen treatment apparatus and method thereof which are flexible and economical.

Description

Nitrogen treatment equipment for sewage and wastewater {COMPACT, FLEXIBLE AND ECONOMICAL NITROGEN REMOVAL PROCESS FOR MUNICIPAL AND INDUSTRIAL WASTE WATER}

The present invention relates to a nitrogen treatment apparatus for sewage and wastewater, and in particular, the use of a carbon source by sewage and wastewater sludge heat treatment and a high concentration of nitrogen treatment of sludge dewatering liquor are treated in a stepwise manner by using an aerobic deammonium process. It relates to a device that can.

Recently, as social problems are caused by eutrophication of rivers and lakes, interests in research on technology for removing nitrogen and phosphorus, which are the causes of eutrophication, are expanding. Ammonia nitrogen is a causative agent of eutrophication and is known as a toxic substance of aquatic organisms in water, and research on its removal technology has been conducted for a long time, but it is still insufficient in practical use due to construction cost and maintenance cost for nitrogen removal. Furthermore, since 2003, since the water quality standards are applied to industrial wastewater, it is urgent to spread the nitrogen removal treatment technology of industrial wastewater including high concentration nitrogen.

On the other hand, the nitrogen removal in the waste water can be divided into physical and chemical methods and biological methods, biological removal method is known to be the most effective and economical. In biological treatment, organic nitrogen and ammonia nitrogen present in sewage and waste water are oxidized to nitrous acid or nitrous nitrogen using oxidizing bacteria under aerobic conditions, and then reduced to nitrogen gas using denitrifying bacteria under anoxic conditions. It is a treatment method to release.

Currently, even in the biological nitrogen removal treatment method, the reduction of power cost according to the oxygen supply in the nitrification process and the reduction of the organic carbon source in the denitrification process are most demanded.

In addition, many technologies and studies are being conducted on more economical nitrogen treatment methods in sewage and wastewater treatment plants for which the C / N ratio is not appropriate or industrial wastewater treatment plants for high concentration nitrogen treatment. In particular, even in domestic sewage treatment plants, a large amount of external carbon sources are required for advanced treatment, and in the development of the external carbon sources, most of the researches on the method using sewage sludge are performed by acid fermentation using microorganisms.

Therefore, the present invention is for sewage treatment plants adjacent to industrial areas that require such energy savings and organic carbon source reduction, sewage and wastewater treatment plants where C / N ratio is not appropriate, and sewage treatment plants requiring sewage excess sludge treatment. Developed for the purpose of developing an external carbon source and renting a surplus carbon source, and for nitrogen treatment with high concentration of dehydration solution with low C / N ratio, it is possible to treat nitrogen with a low oxygen amount without administering an external carbon source. main) It aims to provide a nitrogen treatment system for sewage and wastewater by adjusting the C / N ratio of the sewage treatment plant and step by step of pre and post treatment of industrial wastewater treatment plant.

The present invention for achieving the above object, the primary sedimentation basin for sedimentation sludge contained in sewage or waste water; A nitrogen treatment tank comprising a plurality of tanks provided with a stirrer and filled with carriers, for removing nitrogen contained in the sewage supplied from the primary sedimentation basin; A secondary sedimentation basin for settling sludge contained in the microorganisms and sewage generated for nitrogen treatment in the nitrogen treatment tank; A concentrating tank for concentrating the sludge discharged from the first and second settling basins; A high temperature / high pressure heat treatment tank for converting the sludge supplied from the concentration tank to an external carbon source by heat-treating the sludge for 10 to 30 minutes at a high temperature of 150 to 180 ° C. and a high pressure of 5 to 10 Bar; A dewatering apparatus for dewatering the heat treatment solution generated by the high temperature and high pressure heat treatment tank; A heat treatment liquid tank for storing the heat treatment liquid supplied from the dehydration apparatus, and supplying the heat treatment liquid to the nitrogen treatment tank and a fermentation tank for fermenting the solid sludge discharged from the dehydration apparatus; The dehydration liquid supplied from the digester is characterized by consisting of an aerobic deammonium tank for high concentration nitrogen treatment using a carrier.

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DETAILED DESCRIPTION A detailed description of preferred embodiments of the present invention will now be described with reference to the accompanying drawings. In the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

First, in the present invention, by adopting a method of using a thermal hydrolysate by thermal hydrolysis at high temperature and high pressure as an external carbon source, the external carbon source generation rate is higher than that of biological acid fermentation, and sludge dewatering is improved, and the effect of sterilization is also improved. In addition, the present invention proposes a nitrogen treatment system for sewage and wastewater that is excellent in process stability.

In addition, the present invention combines aerobic deammonium bath with MBBR (Moving Bed Biofilm Reactor) process to integrate nitrosamines and aerobic denitrifiers into artificial tanks in the same tank to make ammonia in the influent as a hydrogen donor. As shown in Formula 1 below, the denitrification is performed by autotrophic bacteria having nitrite nitrogen generated by nitrosoamine bacteria as a hydrogen receptor.

{Formula 1}

_{^{NH 4 + + NO 2 - →}} N 2 + 2H 2 O (△ GO '= -358KJ / mol NH 4 +)

On the other hand, the present invention can reduce the amount of oxygen supplied by nitrification by 60%, has the advantage that no organic carbon source is required when denitrification, MBBR process to be used in the present invention is the existing intermittent aeration method, A20, A0 and SBR Compared to the construction method, it is resistant to microbial impact load, there is little microbial closure phenomenon, and there is no need for transportation, so it is easy to manage and install, and it has a big advantage that it can be applied to the existing nitrogen treatment facility.

In the case of a sewage treatment plant, the present invention uses a thermal hydrolysate as an external carbon source, and the dehydration solution is aerobic deammonium (Aerobic) method using a main sewage treatment nitrogen process stem, low oxygen administration, and a method that does not require an external carbon source. Pretreatment economically with Deammonification, and a complex nitrogen treatment method for treating total nitrogen step by step is a feature of the present invention. In particular, by using the carrier appropriately for the stability of the method against the load variation or the temperature change in the biological treatment method and the activation of the characteristic microbial group, the additional fixed cost part of the carrier optimizes the use of the carrier. It is included in the scope of development to enable economic feasibility and to consider economic aspects.

In addition, in the case of industrial wastewater, the microbial treatment method that requires an external carbon source with a concentration of nitrogen of about 1000 mg / L or more is not very economical. The present invention does not require an external carbon source, and can be economically pretreated by an aerobic deammonium method that can remove nitrogen at low oxygen concentration, and in order to guarantee more stringent effluent nitrogen water quality, a post-treatment using a carrier having a heat treatment solution as an external carbon source It is a characteristic of the invention to use a nitrogen treatment method.

Hereinafter, the present invention will be described in detail based on the preferred embodiments of the present invention, but the present invention is not limited to the embodiments.

{Example 1}

1 is a view showing a method and an overall mechanism of treating sewage using a nitrogen treatment apparatus including a high temperature / high pressure heat treatment tank and an aerobic deammonium bath according to the present invention, with reference to the drawings. The description is as follows.

Referring to FIG. 1, the pretreatment tank 10 agitates the inorganic coagulant and the sewage supplied through the pipe (a), and the primary sedimentation basin 12 is the polymer coagulant and the pretreatment tank supplied through the pipe (b). The sewage stirred at 10 is mixed and introduced and the sludge contained in the sewage is precipitated. At this time, the primary sedimentation basin 12 is connected to the pipe (e), the sludge precipitated through the pipe (e) is transferred to the concentration tank (18).

Nitrogen treatment tank 14 is introduced into the sewage from which the sludge has been removed by the primary sedimentation basin 12, the nitrogen contained in the sewage is removed using a carrier (34). In addition, the nitrogen treatment tank 14 is composed of a plurality of tanks, specifically, about seven tanks, which are connected to each other, and each tank is provided with an agitator. On the other hand, the tank 14a installed on the outermost side of the nitrogen treatment tank 14 described above serves to remove excess carbon (C), and the inner circulation pipe (c) is connected to the tank located in the fourth in FIG. Through the pipe (c) the sewage converted to "NH ₄ → NO ₃ " is introduced back into the tank located first.

Secondary sedimentation basin 16 is introduced into the sewage from which nitrogen is removed from the nitrogen treatment tank 14, and preferably at least about 90% of nitrogen is removed, such as " NH ₄ → NO ₃ → N ₂ ↑. &Quot; That is, the secondary sedimentation basin 16 is mixed with the inorganic coagulant supplied through the pipe (i) and the nitrogen-free sewage is introduced into the sediment and precipitate the sludge contained in the sewage. At this time, the secondary sedimentation basin 16 is connected to the pipe (f), the sludge precipitated through the pipe (f) is transferred to the concentration tank (18).

On the other hand, the concentration tank 18 serves to concentrate the sludge discharged from the above-described primary sedimentation basin 12 and the secondary sedimentation basin 16, the high temperature, high pressure heat treatment tank 20 of the present invention As a main component, the concentrated sludge is heat-treated for 10 to 30 minutes at a high temperature of 150-180 ° C. and a high pressure of 5-10 BAR to generate an external carbon source (hereinafter referred to as “heat treatment liquid”).

The dewatering device 22 dehydrates the hot / high pressure treated sewage, preferably the heat treatment liquid generated by the above-described high temperature / high pressure heat treatment tank 20, so that the solid sludge is digested through the pipe h. The heat treatment liquid is discharged to and sent to the heat treatment liquid tank 24. The heat treatment solution tank 24 stores the heat treatment solution CS and sends the heat treatment solution to the fifth tank of the nitrogen treatment tank 14 through the pipe g. At this time, in the nitrogen treatment tank 14, preferably, in the fifth and sixth tanks, nitrogen contained in the sewage is removed (NO ₃ → N ₂ ↑).

The digester 26 fermented the solid sludge to reduce the volume to 1/10, and the dehydrator 28 dehydrates the fermented sludge to discharge the sludge as a solid, and the dehydrated filtrate was transferred to the storage tank 30. send. In this case, the dehydration liquid refers to a liquid containing very little organic matter and containing only a large amount of nitrogen.

The aerobic deammonium bath 32 consists of three tanks, each of which is filled with carriers 34. The aerobic deammonium tank 32 is subjected to a high concentration of nitrogen treatment using a carrier using a dehydration liquid (that is, a dehydration liquid containing very little organic matter and a large amount of nitrogen) supplied from the dehydration liquid storage tank 30. At this time, the aerobic deammonium treatment liquid is transferred to the primary settling tank 12 through a pipe (d). At this time, the carrier accumulates nitrite and aerobic denitrification bacteria, i.e., two specific species present in sewage sludge. It is grown after inoculation naturally under operating conditions to form a microbial membrane and attached to a carrier for high concentration nitrogen treatment, which is described in detail in the above formula (1).

{Example 2}

FIG. 2 is a view showing a method and overall mechanism of treating wastewater using a nitrogen treatment apparatus including a high temperature / high pressure heat treatment tank and an aerobic deammonium tank according to the present invention, with reference to the drawings. The description is as follows.

Referring to FIG. 2, the primary flow rate storage tank 50 is a place for storing wastewater introduced from the outside, and the aerobic deammonium tank 52 is composed of three tanks filled with carriers 54 and the primary About 80% of nitrogen contained in the wastewater supplied from the flow regulating tank 50 is removed using the carrier 34.

The primary sedimentation basin 56 precipitates the sludge contained in the wastewater from which nitrogen was removed by the above-mentioned aerobic deammonium tank 52. At this time, the primary sedimentation basin 56 is connected to the pipe (f), the sludge precipitated through the pipe (f) is transferred to the concentration tank (64). On the other hand, the secondary flow control tank 58 is a place for storing the wastewater from which the sludge is removed by the primary sedimentation basin 56.

The nitrogen treatment tank 60 removes the wastewater supplied from the secondary flow control tank 58 using the carrier 34, and preferably removes the nitrogen contained in the wastewater. In addition, the nitrogen treatment tank 60 is composed of a plurality of tanks, in particular about seven tanks, which are connected to each other, each tank is provided with a stirrer. On the other hand, the tank 60a installed on the outermost side of the above-described nitrogen treatment tank 60 controls surplus carbon (C), and the inner circulation pipe (b) is connected to the fourth tank in FIG. Through the pipe (b), the wastewater converted to “NH ₄ → NO ₃ ” is introduced back into the tank located first.

Wastewater from which nitrogen is removed from the nitrogenous treatment tank 60, preferably “NH ₄ → NO ₃ → N ₂ ↑”, is removed from the secondary sedimentation basin 62 by 90% or more. That is, the secondary sedimentation basin 62 is mixed with the inorganic coagulant supplied through the pipe (a) and the waste water from which nitrogen is removed to flow in together and settle the sludge contained in the waste water. At this time, the secondary sedimentation basin 62 is connected to the pipe g, and the sludge precipitated through the pipe g is transferred to the concentration tank 64.

On the other hand, the concentration tank 64 serves to concentrate the sludge discharged from the primary settling basin 56 and the sludge discharged from the secondary settling basin 62, the high temperature, high pressure heat treatment tank 66 of the present invention As a main component, the concentrated sludge is heat-treated for 10 to 30 minutes at a high temperature of 150-180 ° C. and a high pressure of 5-10 BAR to generate an external carbon source (hereinafter referred to as “heat treatment liquid”).

The dewatering apparatus 68 dehydrates the hot / high pressure treated wastewater, preferably the heat treatment solution generated by the above-described high temperature / high pressure heat treatment tank 20, so that the solid sludge is digested through the pipe c. The heat treatment liquid discharged to the dehydration and sent to the heat treatment liquid tank (70). The heat treatment liquid tank 70 stores the heat treatment liquid CS, and sends the heat treatment liquid to the fifth tank of the nitrogen treatment tank 60 through the pipe d. At this time, in the nitrogen treatment tank 60, preferably in the fifth and sixth tank to remove the nitrogen contained in the sewage (NO ₃ → N ₂ ↑).

The digester 72 fermented the solid sludge to reduce the volume to 1/10, and the dehydrator 74 dehydrates the fermented sludge to discharge the sludge made of solids, and the dehydrated filtrate discharges the pipe (e). It is sent to the nitrogen treatment tank 60 through. At this time, the dehydration liquid refers to a liquid containing very little organic matter and a large amount of nitrogen.

On the other hand, it can be seen that the present invention is applicable to a sewage treatment plant or a wastewater treatment plant as described in Examples 1 and 2, and in the following for the configuration and method shown in Examples 1 and 2 through a brief test It will demonstrate that we can finally commercialize the present invention while increasing our understanding and laying the groundwork for a more full scale pilot plant.

{Experiment 1} Sludge Heat Treatment Test

1. Experiment Overview

: Dehydration of 1st and 2nd sludge of J sewage treatment plant, heat treatment at 150 ~ 180 ℃ and high pressure of 5 ~ 10BAR for 10 ~ 30 minutes, then analyzed the yield and composition of stagnant supernatant. The difference between concentrated sludge and dewatered sludge is mainly water content, and the experiment of dehydration of high temperature and high temperature heat treatment in Experiment 1 is a problem of the capacity of laboratory high temperature and high pressure heat treatment machine. In particular, when applied in actual field, when transporting sludge from another sewage treatment plant to a sewage treatment plant with high temperature and high pressure heat treatment, the dehydration and transport are mainly performed, thereby giving the meaning of a complex experiment.

2. Experimental Results

1) Yield

160 ° C: 22% of COD _f

180 ° C: 28% of COD _f

2) Content

3. Reference test

Yield: 10-15% of COD _f

2) Content

{Experiment 2} Nitrogen treatment test using external carbon source of thermal hydrolysate

1. Experiment Overview

: Analysis of the results of utilization of the carbon source by applying a nitrogen treatment step using a carrier using the carbon source of the heat treatment solution.

2. Test condition

1) Sample: Primary Sewage Treatment Plant

          COD: 150mg / L

NH ₄ ⁺ -N: 70mg / L

          T-N: 70mg / L

2) Temperature condition: 20 ℃

3) REACTOR VOLUME: 4L × 7EA

4) FLOW: 224L

5) PERIOD: In other words, the test conditions used for the first treatment of the raw water of the S sewage treatment plant in order to maintain the objectivity of the test, the temperature conditions, the capacity of the test tank and the inflow flow rate is generally It was close to the sewage treatment plant operation and the duration was 6 months.

3. Test result

Nitrogen treatment efficiency is mainly represented by the improvement of inflow and outflow concentration of TN, but it shows the accuracy of the experiment by tracking the nitrogen treatment process through various analysis in the arrangement of experimental data, and analyzes the activity of each microorganism. In most sewage treatment plants, the efficiency of NO ₃ -N in the primary treatment water is that NH ₄ -N is changed to NO ₃ -N primarily during nitrogen treatment, that is, NH ₄ -N 70mg / L is NO ₃ -N mg / L. And the effluent NO ₃ -N is 6 mg / L (70-6 / 70), the efficiency is 91.4%.

{Experiment 3} Aerobic Deammonification Test

1. Experiment Overview

: Denitrification by autotrophic bacteria with ammonia in influent as hydrogen donor and nitrite nitrogen produced by nitrosamine bacteria as hydrogen acceptor, maintaining low oxygen concentration and high concentration nitrogen without using external carbon source (mg / L) test for removal. At this time, without using the external carbon source described above, the heat treatment solution according to the present invention is used as an external carbon source as well as all expensive external carbon sources used in existing sewage and wastewater treatment plants, 'Without external carbon source' represents a very economical device.

2. Chemical formula

_{^{NH 4 + + NO 2 - →}} N 2 + 2H 2 O (△ GO '= -358KJ / mol NH 4 +)

3. Test condition

1) Sample: S company wastewater

COD _Cr : 180mg / L

NH ₄ ⁺ -N: 1000 mg / L

2) Temperature condition: 27 ℃

3) REACTOR VOLUME: 4L × 3EA

4) FLOW: 15L / day

5) PERIOD: 6 months on the other hand, the sample used S company wastewater containing high concentration of nitrogen, and the temperature condition, test tank capacity and inflow rate were not applied in the existing sewage and wastewater treatment plant. The vehicle was operated under conditions suitable for the conditions, and the period was 6 months.

4. Test result

As described above, the nitrogen treatment apparatus for sewage and wastewater according to the embodiment of the present invention achieves many effects as follows.

Firstly, the yield of the heat treatment solution, that is, the percentage of the COD value of the sludge before the heat treatment divided by the value of the COD _f filtered after the heat treatment, is 28%. Are different but have a similar composition.

Secondly, the heat treatment solution as an external carbon source has an efficiency of about 90% or more in the nitrogen treatment method using a carrier.

Third, the efficiency of nitrogen treatment without high oxygen and external carbon source of industrial wastewater with high concentration of inflow and high load resulted in more than 80%.

1 is a view showing a method of treating sewage using a nitrogen treatment apparatus having a high temperature and high pressure heat treatment tank and an aerobic deammonium tank according to a first embodiment of the present invention.

2 is a view showing a method for treating wastewater using a nitrogen treatment apparatus having a high temperature / high pressure heat treatment tank and an aerobic deammonium tank according to a second embodiment of the present invention.

Claims (4)

delete delete In the apparatus capable of treating nitrogen in sewage and wastewater, A primary sedimentation basin for settling sludge contained in the sewage or waste water; A nitrogen treatment tank comprising a plurality of tanks provided with a stirrer and filled with carriers, for removing nitrogen contained in the sewage supplied from the primary sedimentation basin; A secondary sedimentation basin which precipitates sludge contained in the sewage from which nitrogen is removed in the nitrogen treatment tank; A concentrating tank for concentrating the sludge discharged from the first and second settling basins; A high temperature / high pressure heat treatment tank for converting the sludge supplied from the concentration tank to an external carbon source by heat-treating the sludge for 10 to 30 minutes at a high temperature of 150 to 180 ° C. and a high pressure of 5 to 10 Bar; A dewatering apparatus for dewatering the heat treatment solution generated by the high temperature and high pressure heat treatment tank; A heat treatment liquid tank for storing the heat treatment liquid supplied from the dehydration apparatus, and supplying the heat treatment liquid to the nitrogen treatment tank and a fermentation tank for fermenting the solid sludge discharged from the dehydration apparatus; A nitrogen treatment apparatus for sewage and wastewater, characterized in that the dewatering liquid supplied from the digester is composed of an aerobic deammonium tank for treating a high concentration of nitrogen by an aerobic deammonium method using a carrier. delete