JP2013226491A - Method and apparatus for nitrous acid-type nitrification treatment of nitrogen-containing wastewater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the following problem: ammonia nitrogen and nitrite nitrogen can be mixed together to show an optimum ratio, when a nitrite nitrogen solution can be efficiently produced, because the ratio between the ammonia nitrogen and the nitrite nitrogen, which can be efficiently decomposed, cannot be easily adjusted by pH, though an anammox method, in which the ammonia nitrogen can be decomposed even into nitrogen gas and water, has the advantage that efficient decomposition can be performed.SOLUTION: A method for producing a nitrite nitrogen solution includes the steps of: loading ammonia nitrogen-containing wastewater into a treatment tank; loading a microbial community, which has three capabilities, that is to say, an ammonia nitrogen oxidizing capability, a nitrite nitrogen oxidizing capability and nitrate nitrogen reducibility, into the treatment tank; and aerating the inside of the treatment tank.

Description

  The present invention relates to a production method and a production apparatus for producing nitrite nitrogen that can be used for treating wastewater containing ammonia nitrogen by using microorganisms from wastewater containing nitrogen.

In the treatment of nitrogen-containing wastewater, treatment of ammonia nitrogen is important. Several methods are known for treating ammonia nitrogen. As a scientific treatment method, for example, an ammonia stripping method is known. This decomposes ammoniacal nitrogen into water (H ₂ O) and ammonia (NH ₃ ) in a solution having a high pH. Ammonia can be released into the atmosphere or recovered in the form of ammonium sulfate. However, the scientific method has a problem that it is expensive in terms of pH adjustment and temperature adjustment.

  On the other hand, a method of treating ammonia nitrogen using a microorganism is also known. This is a procedure in which ammonia nitrogen is converted to nitrite nitrogen and nitrate nitrogen by nitrifying bacteria, and water and nitrogen gas are generated from nitrate nitrogen by denitrifying bacteria. This method is considered good for the environment because it decomposes ammonia nitrogen into nitrogen gas. However, organic matter such as methanol is required for the activity of denitrifying bacteria. Since this organic matter must be added artificially, the cost for this is required.

  An anammox method is known as another method for treating ammonia nitrogen using a microorganism. This method utilizes autotrophic denitrifying microorganisms (referred to as “anammox microorganisms”) to decompose ammoniacal nitrogen and nitrite nitrogen mainly into nitrogen and water. Anammox microorganisms do not require organic substances for denitrification. That is, it has a feature that ammonia nitrogen can be decomposed at a very low cost.

  Patent Document 1 provides a method for treating ammonia nitrogen by this method. FIG. 5 outlines this method. This nitrification method includes a nitrification tank 101 for treating raw water, a pump 105 for feeding raw water to the nitrification tank 101, a pH sensor 102 disposed in the nitrification tank 101, and an output of the pH sensor 102. Based on the controller 103 that controls the pump 105 based on the above.

  In the anammox method, the ratio of ammonia nitrogen and nitrite nitrogen is regarded as important for improving the treatment efficiency. That is, it is said that the efficiency is highest when the ratio of nitrite nitrogen to ammonia nitrogen 1 is in the range of 0.5-2. The pH sensor 102 disposed in the nitrification tank 101 is disposed to manage this ratio. Since ammonia nitrogen is alkaline and nitrite nitrogen is acidic, the pH changes when the ratio of ammonia nitrogen and nitrite nitrogen changes. The controller 103 controls the pump 105 so as to increase the supply amount of the raw water when the pH of the solution in the nitrification tank 101 is shifted to the acidic side.

JP 2003-24983 A

  The Anammox method has the advantage that ammonia nitrogen can be decomposed into nitrogen gas and water, and the cost is not increased. However, as in the method of Patent Document 1, it is not easy to control the ratio of ammonia nitrogen and nitrite nitrogen with pH. In particular, since pH is affected by carbon dioxide and temperature, it can be said that it is a very difficult control.

The present invention has been conceived in view of the above problems, and a method and apparatus for efficiently producing a nitrite-based nitrogen solution that can be used in the anammox method, a nitrite-type nitrification method for nitrogen-containing wastewater, and nitrogen-containing wastewater It is provided as a processing device. More specifically, the nitrite type nitrification treatment method of the present invention is:
A step of introducing wastewater containing nitrogen components into the treatment tank;
Introducing a group of microorganisms having three abilities of ammonia nitrogen oxidizing ability, nitrite nitrogen oxidizing ability, and nitrate nitrogen reducing ability into a treatment tank;
Aeration of the inside of the treatment tank;
It is characterized by having.

Moreover, the nitrogen-containing wastewater treatment apparatus of the present invention is
A treatment tank into which wastewater having a nitrogen component is introduced;
A culture tank for producing a culture solution in which a group of microorganisms having three capabilities of ammonia nitrogen oxidizing ability, nitrite nitrogen oxidizing ability, and nitrate nitrogen reducing ability are cultured together with a medium;
Liquid feeding means for feeding the culture solution from the culture tank to the treatment tank;
It has the aeration apparatus which aerates the inside of the said processing tank, It is characterized by the above-mentioned.

  In the present invention, a microorganism group having three abilities, ammonia nitrogen oxidization ability, nitrite nitrogen oxidization ability and nitrate nitrogen reduction ability is used, so that ammonia nitrogen and nitrate nitrogen are treated with nitrite nitrogen. be able to. This solution containing nitrite nitrogen (referred to as “sub-raw water”) can be used for raw water treatment using the Anammox method.

  In other words, the ratio of ammonia nitrogen and nitrite nitrogen in the anammox method has been found to be effective at a predetermined value, so the ratio of ammonia nitrogen in the treatment tank and the ratio of nitrite nitrogen can be directly calculated. Raw water and secondary raw water can be mixed to measure and to the most effective ratio.

  In addition, the secondary raw water can be decomposed into water and nitrogen gas and recovered by performing subcritical treatment with equimolar ammoniacal nitrogen.

It is a figure explaining the structure of the manufacturing apparatus of the nitrite nitrogen solution which concerns on this invention. It is a graph which shows the ammoniacal nitrogen oxidation ability of the microorganisms group which concerns on this invention. It is a graph which shows the ammoniacal nitrogen oxidation ability (when pH = 8.0) of the microorganisms group which concerns on this invention. It is a figure which shows the processing capacity of ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen of each microorganism. It is a figure which shows the structure of the apparatus which enforces the conventional anammox method.

  Hereinafter, although the present invention is explained using a drawing, the following explanation illustrates one embodiment of the present invention and is not limited to the following embodiment. The following description can be changed without departing from the spirit of the present invention.

  The microorganism group used in the present invention has the ability to oxidize ammonia nitrogen (ammonia nitrogen oxidation ability), the ability to oxidize nitrite nitrogen (nitrite nitrogen oxidation ability), and the ability to reduce nitrate nitrogen. It is a group of microorganisms having both (nitric nitrogen reducing ability). More specifically, the ammoniacal nitrogen oxidizing ability refers to the ability to oxidize ammoniacal nitrogen to nitrite nitrogen. The nitrite nitrogen oxidizing ability refers to the ability to oxidize nitrite nitrogen to nitrate nitrogen. The nitrate nitrogen reducing ability is the ability to reduce nitrate nitrogen to nitrite nitrogen.

  At present, microorganisms having such ability are not known in nature. The inventor of the present invention obtained a group of microorganisms having these three abilities by acclimating and culturing aerobic nitrifying bacteria in a high concentration ammonia environment. The group of microorganisms having such ability is composed of microorganisms belonging to the genus Pseudomonas (genus Pseudomonas), the genus Brevibacillus (genus Brevibacillus), the genus Acinetobacter (genus Acinetobacter), and the genus Microbacterium (genus Microbacterium) by 16S rDNA search. I found out.

  In the method for producing a nitrite nitrogen solution of the present invention, these microorganism groups are cultured in a medium to produce a culture solution.

  These microorganism groups were obtained by the following method. First, a ready-to-use deodorant microorganism preparation (Effective Micro organism groups; Biotorster manufactured by Trent) was used as an inoculum. This inoculum is an aerobic and nitrifying group of bacteria (multiple types are mixed). The inoculum was continuously aerated at room temperature, and the medium was changed at regular intervals, and acclimation culture was performed to increase the ammonium ion concentration each time. Table 1 shows the components of the medium.

  As the ammonium ion source, ammonium sulfate was used. The first time was started from a concentration of 2,500 mg / L, and the concentration was increased 10 times to 25,000 mg / L at the 10th medium replacement. The medium was replaced when the ammonium ion concentration decreased by 50% or more. Note that the pH of the medium was adjusted with NaOH so as to be 7-8.

  After exchanging the medium for the 10th time, the oxidizing ability of the cultivated microorganism group was examined. FIG. 2 shows the result. The horizontal axis is time (days), and the vertical axis is the nitrogen concentration (ppm). The pH is maintained at 7.8. The squares are ammoniacal nitrogen concentrations, the diamonds are sulfite nitrogens, and the triangles are nitrate nitrogens. In medium with conditioned cultures (also called “microorganisms”), ammoniacal nitrogen decreased with time, and nitrite nitrogen increased its concentration. Also, the amount of nitrate nitrogen did not increase at all.

  When the medium is in the acidic region (pH 3.0 to less than pH 6.0), the rate of oxidation to nitrite nitrogen is small, and even when the ammoniacal nitrogen-containing solution is in the alkaline region (pH 9.0 to pH 11.0) Although the rate of oxidation to nitrite nitrogen was small, the rate of oxidation to nitrite nitrogen increased in the region where the pH was 6.0 or more and less than 9.0, and as shown in FIG. In the vicinity, the oxidation rate was particularly high. According to this result, almost 60% of the ammoniacal nitrogen was oxidized to nitrite nitrogen after 60 days. In addition, nitrate nitrogen was not increased at all.

  A method for identifying the cultivated microorganism group as containing the above four species will be described later. Colonies were made using an agar medium, and each of these four species was isolated and examined for its ability. FIG. 4 shows ammonia nitrogen, nitrous acid for each of FIG. 4 (a) Brevibacillus, FIG. 4 (b) Pseudomonas, FIG. 4 (c) Microbacterium, and FIG. 4 (d) Acinetobacter. It is the result of investigating the change of each component when giving nitrogen and nitrate nitrogen and culture | cultivating on the favorable conditions for 80 days. The black square is ammoniacal nitrogen, the black circle is nitrite nitrogen, and the black triangle is nitrate nitrogen. In both bacteria, ammonia nitrogen and nitrate nitrogen decreased, and nitrite nitrogen increased.

  From this, it can be said that this cultivated bacterial group has the ability to oxidize ammonia nitrogen, which decomposes ammonia nitrogen into nitrite nitrogen. Moreover, since nitrate nitrogen is decreased and nitrite nitrogen is increased, it can be said that there is at least nitrate nitrogen reducing ability when viewed as a group of microorganisms collected from these fungal groups. Considering that these microorganisms are aerobic nitrifying bacteria in the first place, it is considered that they have nitrite nitrogen oxidizing ability to oxidize nitrite nitrogen to nitrate nitrogen. Therefore, these microbial groups are microbial groups having three abilities, ammoniacal nitrogen oxidizing ability, nitrite nitrogen oxidizing ability, and nitrate nitrogen reducing ability. In addition, at least these microbial groups have ammonia nitrogen oxidizing ability and nitrate nitrogen reducing ability.

  The microorganisms obtained by culturing in this way were judged to be the same species as the above four types of bacteria with a homology of 99% or more. For identification, 16S rDNA nucleotide sequence analysis was used. 16S rDNA is DNA having genetic information of 16S rRNA that constitutes a small subunit that is a part of a ribosome. This DNA exists in any organism and has a difference in base sequence between different species. Therefore, it is suitable for species discrimination. Particularly in bacteria, certain parts have a common base sequence. Therefore, the same primer (universal primer) can be used for DNA amplification.

  Then, the 16S rDNA of these microorganisms and the sequences of known microorganisms are available on the database (DDBJ / EMBL / GenBank http://www.ddbj.nig.ac.jp/intro-j.html) The homology was examined by performing a BLAST search.

  A more specific procedure was as follows. First, the DNA of the conditioned microorganism was extracted using a commercially available DNA extraction kit. Next, this DNA was subjected to PCR amplification using 9F primer and 926R primer to amplify 16SrDNA. The nucleotide sequence was analyzed from the amplified 16S rDNA. The analyzed base sequence was subjected to BLAST search to examine microorganisms with high homology.

  As a result of the above, the microorganism group obtained by acclimation culture includes 99% of microorganisms belonging to the genus Pseudomonas, the genus Brevibacillus, the genus Acinetobacter, and the genus Microbacterium. Microorganisms having the same homology. That is, the group of microorganisms used in the present invention is a group of microorganisms that have been conditioned and cultured so that the aggregate of microorganisms belonging to these four genera has nitrate nitrogen reducing ability.

  In other words, these microorganism groups consist of microorganisms belonging to any of the above four genera with 99% homology in the 16S rDNA homology search, and can further reduce nitrate nitrogen to nitrite nitrogen. It can be said that it is a microbial group.

  After acclimation culture, these microorganisms are cultured in a medium to obtain a culture solution. The medium may be the medium shown in Table 1 or may be waste water containing nitrate nitrogen. When culturing, the temperature is preferably about 25 to 40 ° C. This is because the higher the liquid temperature, the easier the growth.

  FIG. 1 shows a manufacturing apparatus (processing apparatus) 1 for a nitrite-based nitrogen solution according to the present invention. The apparatus 1 for producing a nitrite nitrogen solution of the present invention includes a treatment tank 2, a liquid feed pump 4 for feeding raw water to the treatment tank 2, a discharge pump 6 for discharging the treatment liquid from the treatment tank 2, and a treatment tank. 2, an aeration apparatus 8 for aeration, a culture tank 10 for storing a culture solution in which the above-described microorganism group is cultured, a culture solution pump 12 for sending the culture solution from the culture tank 10 to the treatment tank 2, and the treatment tank 2. DO detector 14, pH detector 15, ammonia concentration detector 16, nitrous acid concentration detector 17, and nitric acid concentration detector 18, and these detectors, feed pump 4, and discharge pump disposed in the interior 6. A control device 20 is connected to the culture solution pump 12 and controls various pumps based on signals from the detection device.

  The processing tank 2 is a container having a necessary size and desirably has a lid. This is to eliminate contamination of bacteria other than the microorganism used in the present invention. A diffuser pipe 8b is fixed to the bottom of the treatment tank 2, and a blower pipe 8c (shown by a one-dot chain line) extending from the diffuser pipe 8b continues to the outside of the treatment tank 2. A blower 8a is connected to the blower pipe 8c, and a necessary amount of air can be sent to the diffuser pipe 8b. The blower 8a is connected to the control device 20, and the control device 20 can control the air volume of the blower 8a with the instruction Cb. The aeration device 8 is configured by the blower 8a, the diffuser tube 8b and the blower tube 8c.

  In the treatment tank 2, a DO detection device 14, a pH detection device 15, an ammonia concentration detection device 16, a nitrous acid concentration detection device 17, and a nitric acid concentration detection device 18 are disposed. Each is a detection device for detecting the state of the processing liquid in the processing tank 2, and there may be a detection device other than the detection device raised here. In addition, the detection apparatus raised here is called the detection means 19.

  Raw water is waste water having a nitrogen component. That is, the raw water may be domestic water such as sewage as well as waste water from the factory. Alternatively, treated water that has already been treated with aerobic nitrifying bacteria may be used. This is because the group of microorganisms used in the present invention can be reduced to nitrite nitrogen even if oxidation proceeds to nitrate nitrogen. Moreover, ammonia nitrogen may be contained in high concentration in the waste water to be treated.

  The culture tank 10 is charged with the culture medium and the microorganism group according to the present invention. A mixture of a culture medium and a group of microorganisms is called a culture solution. In order to allow microorganisms to grow in the culture tank 10, a heater 10h and a temperature sensor 10T may be arranged in the culture tank 10. These heater 10 h and temperature sensor 10 T are also connected to the control device 20. The heater 10h is connected to a power source 10hb and is configured to be energized under the control of the switch 10hs.

  The control device 20 can control the temperature in the culture tank 10 by detecting the temperature in the culture tank 10 with the temperature signal Tb from the temperature sensor 10T and controlling the switch 10hs with the instruction Chs. A culture solution pump 12 is connected to the culture tank 10, and the culture solution can be supplied into the treatment tank 2 through the liquid supply pipe 12 p. A liquid feeding means is formed by the culture liquid pump 12 and the liquid feeding pipe 12p. In addition, a liquid feeding means is not limited to the structure of the culture solution pump 12 and the liquid feeding pipe 12p, You may be comprised by another method. For example, a necessary amount of culture solution is weighed, put into a separate container, and put into the treatment tank 2. This culture medium pump 12 is also connected to the control device 20 and controlled by an instruction Cm from the control device 20.

  A drain pipe 6p is connected to the treatment tank 2, and a drain pump 6 is connected to the drain pipe 6p. This is because the treated solution is discharged from the treatment tank 2. The drainage pump 6 is also connected to the control device 20 and its operation is controlled by an instruction Cex from the control device 20.

  Filter means 22 may be provided on the upstream side of the discharge pump 6. The filter means 22 is for filtering the treatment liquid to filter out the microorganism group. Therefore, an MF membrane (Microfiltration Membrane) capable of filtering about 0.1 to 1.0 μm can be suitably used as the filter.

  Since a large number of microorganisms remain in the treatment liquid that has not passed through the filter means 22, this residual liquid is returned to the culture tank 10 or the treatment tank 2. This is because the microorganism group of the present invention is a valuable microorganism having three abilities by acclimation culture, and is intended for reuse.

  The control device 20 determines the state in the treatment tank 2 based on the measurement value from the detection means 19, discharges the treatment liquid and throws the raw water into the treatment tank 2 according to the situation where the raw water is treated, Further, the culture solution is added from the culture tank 10 to the treatment tank 2. Moreover, the state in the culture tank 10 may be determined and the temperature of the processing tank 10 may be controlled.

  Operation | movement of the manufacturing apparatus 1 of the nitrite nitrogen solution comprised as mentioned above is demonstrated. In response to an instruction Cin from the control device 20 to the liquid feed pump 4, the liquid feed pump 4 feeds raw water into the treatment tank 2. The liquid level in the processing tank 2 is detected by the liquid level detector 2L and transmitted to the control device 20 by the signal SL.

  When a predetermined volume of raw water is introduced into the treatment tank 2, the control device 20 sends an instruction Cm to the culture solution pump 12 and sends a predetermined amount of culture solution from the culture vessel 10 to the treatment vessel 2. And the control apparatus 20 operates the blower 8a of the aeration apparatus 8 by instruction | indication Cb, and sends oxygen to the raw | natural water in the processing tank 2. FIG.

  By this aeration, the inside of the treatment tank 2 is brought into an oxygen-rich state, and the microorganism group is made to exhibit the ammoniacal nitrogen oxidizing ability that oxidizes ammoniacal nitrogen to nitrite nitrogen under aerobic conditions. In addition, as shown in FIG. 2, the cultivated microorganism group is reacted up to nitrous acid, and the reaction is stopped, and nitric acid is not oxidized. Further, even if the reaction proceeds to nitric acid or raw water containing nitrate nitrogen is added, it is reduced to nitrite nitrogen. Changes in these component concentrations are monitored by the ammonia concentration detector 16, the nitrous acid concentration detector 17, and the nitric acid concentration detector 18.

  Aeration does not need to be performed continuously, and may be performed mainly based on the dissolved oxygen concentration detected by the DO detector 14. Or you may consider the value of ammonia concentration, nitrous acid concentration, and nitric acid concentration. That is, it is only necessary to aerate the microorganism group so as to efficiently perform the ammoniacal nitrogen oxidizing ability and the nitrite nitrogen oxidizing ability. By doing in this way, an operating cost can be reduced.

  The control device 20 monitors the remaining amount of ammonia by the ammonia concentration detection device 16 in the treatment tank 2. If the ammonia concentration does not decrease in the time examined in advance, the activity of the microorganism group is low or the number of microorganism groups is small. In that case, increase the amount of blower or add more culture solution.

  Further, depending on the pH value detected by the pH detection device 15, an instruction to add a pH adjusting agent may be issued. Of course, you may make it install the automatic charging machine which throws a pH adjuster into the processing tank 2, and throws a pH adjuster by controlling it. In addition, caustic soda (NaOH) etc. can be utilized suitably as a pH adjuster. This is because nitrite nitrogen increases in the treatment tank 2 and the pH tends to the acidic side.

  The control device 20 monitors the increase in the nitrous acid concentration and the decrease in the nitric acid concentration by the nitrous acid concentration detection device 17 and the nitric acid concentration detection device 18, and stops aeration when the ratio reaches a predetermined ratio. Then, the treated water is transferred to the storage tank 25 through the filter means 22, the next treatment liquid is introduced, and the next treatment is started.

  In addition, when the filter means 22 such as an MF membrane is disposed in the drain pipe 6p, the processing liquid that has not been filtered is returned to the processing tank 2 again. In this state, fresh water is added and the same treatment as above is performed. In this case, the amount of the culture solution added to the raw water may be reduced in advance.

  As described above, if the nitrite-type nitrification method of the present invention is carried out in the nitrogen-containing wastewater treatment apparatus 1 of the present invention (also referred to as “a nitrite-nitrogen solution manufacturing apparatus”), Can be obtained in large quantities. Such a nitrite-based nitrogen solution can easily control the anammox reaction by using it as a secondary raw water for setting the ratio of ammonia nitrogen and nitrite nitrogen to a predetermined value in the anammox reaction.

  Also, nitrite nitrogen can be recovered as water and nitrogen gas by performing subcritical treatment together with equimolar amounts of ammonia nitrogen.

  The method for producing a nitrite nitrogen solution of the present invention is suitable for efficiently producing a nitrite nitrogen solution that is useful when converting wastewater containing organic matter such as factory and domestic wastewater into water and nitrogen. Can be used.

DESCRIPTION OF SYMBOLS 1 Manufacturing apparatus of nitrite nitrogen solution 2 Processing tank 2L Liquid level detector 4 Liquid feed pump 6 Discharge pump 6p Drain pipe 8 Aeration apparatus 8a Blower 8b Air diffuser pipe 8c Blower pipe 10 Culture tank 10h Heater 10hb Power supply 10hs Switch 10T Temperature sensor DESCRIPTION OF SYMBOLS 12 Culture liquid pump 12p Liquid feeding pipe 14 DO detection apparatus 15 pH detection apparatus 16 Ammonia concentration detection apparatus 17 Nitrite concentration detection apparatus 18 Nitric acid concentration detection apparatus 19 Detection means 20 Control apparatus 22 Filter means 25 Storage tank

Claims (5)

A step of introducing wastewater containing nitrogen components into the treatment tank;
A process of introducing a group of microorganisms having three capabilities of ammonia nitrogen oxidization ability, nitrite nitrogen oxidation ability, and nitrate nitrogen reduction ability into a treatment tank; and aeration of the inside of the treatment tank. A nitrite-type nitrification method for nitrogen-containing wastewater.   The microorganism group is given oxygen in a high-concentration ammonia environment with at least one bacterium belonging to the genus Pseudomonas (genus Pseudomonas), the genus Brevibacillus (genus Brevibacillus), the genus Acinetobacter (genus Acinetobacter), or the genus Microbacterium (genus Microbacterium). The nitrite-type nitrification method for nitrogen-containing wastewater according to claim 1, comprising microorganisms that have been acclimatized and cultured. A treatment tank into which wastewater having a nitrogen component is introduced;
A culture tank for producing a culture solution in which a group of microorganisms having three capabilities of ammonia nitrogen oxidizing ability, nitrite nitrogen oxidizing ability, and nitrate nitrogen reducing ability are cultured together with a medium;
Liquid feeding means for feeding the culture solution from the culture tank to the treatment tank;
A nitrogen-containing wastewater treatment apparatus, comprising an aeration apparatus for aeration of the inside of the treatment tank.   The microorganism group includes at least one bacterium belonging to the genus Pseudomonas (genus Pseudomonas), the genus Brevibacillus (genus Brevibacillus), the genus Acinetobacter (genus Acinetobacter), the genus Microbacterium (genus Microbacterium), and oxygen in a high-concentration ammonia environment. The treatment apparatus for nitrogen-containing wastewater according to claim 3, characterized in that it contains microorganisms acclimated and cultured while being applied. In the treatment tank,
It has a detection means including at least an ammonia concentration detection device and a nitrite concentration detection device,
5. The nitrogen-containing wastewater treatment apparatus according to claim 3, further comprising a control device that controls the liquid feeding unit based on an output from the detection unit.