JPH1015572A - Bacteria immobilizing carrier and conversion of nitrogen compound in liquid by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inncrease the capacity converting a nitrogen compd. in a liquid by increasing the adsorbing amt. of bacteria on a carrier by providing feathers on the surface of a carrier supporting and holding bacteria. SOLUTION: In an air bubble column type liquid treatment tank 1 fitted with a draft tube, the gas 3 such as nitrogen gas in a tank main body 2 is supplied into the liquid treatment tank 1 from the bottom part 4 thereof to generate flow consisting of ascending flow and descending flow and a liquid 5 to be treated is brought into contact with a carrier 6 to convert a nitrogen compd. In this case, feathers are provided on the surface of the carrier 6 carrying or holding bacteria and, as this carrier, a fiber fabric or knitted fabric is pref. used. The carrier has two or more kinds of shapes selected from a granular shape, a die shape or the like. In order to provide feathers on the surface of the carrier 6, raising treatment or flocking treatment is applied and the treated cloth is cut into a granular shape or a die shape to obtain the carrier 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carrier for immobilizing microorganisms and a method for converting a nitrogen compound in a liquid using the carrier. Specifically, a carrier for immobilizing microorganisms having fluff on the surface and the carrier are put into a liquid treatment tank under aerobic conditions or a liquid treatment tank under anaerobic conditions, and harmful nitrogen contained in tap water or sewage water. The present invention relates to a method for converting a nitrogen compound in a liquid capable of converting or removing a compound into a harmless nitrogen compound.

[0002]

2. Description of the Related Art In recent years, with the increase in consumption of nitrogen fertilizer,
Pollution of groundwater and the like by nitrogen compounds is advancing. It is nitric acid that causes the contamination of groundwater.In Western countries, infants who drink drinking water containing nitric acid have died due to a condition called anemia of blue baby syndrome. It has occurred. This is because the stomach of infants is not acidic, and nitric acid is converted into nitrite by microorganisms in the stomach and combines with hemoglobin in the blood to cause a shortage of oxygen supply, leading to death.

[0003] Therefore, the World Health Organization (WHO) has set the standard for the concentration of nitrate nitrogen in drinking water to 10 ppm. However, 8% of wells in Europe and the United States have detected concentrations of 50 ppm, far exceeding this 10 ppm standard, and in Denmark there are 8% of wells that have detected concentrations of 50 ppm. I have. Some groundwater in the upland areas of Japan exceeds the standard of 10 ppm, and the Ministry of Health and Welfare and the Environment Agency are strengthening the survey as an environmental monitoring item.

[0004] Furthermore, in the treatment of sewage such as sewage, lakes, marshes, and the like have been
The current situation is that eutrophication of rivers has progressed and no fundamental solution has been reached. The treatment method uses an activated sludge method to reduce the biological oxygen demand (BOD) by microorganisms, but can remove nitrogen compounds derived from organic compounds and nutrients such as phosphorus in sewage. Instead, lakes and rivers from which nutrients have been released are in a state where phytoplankton is prone to multiply, and eutrophication progresses again, and pollution progresses.

[0005] In particular, various methods have been employed for removing wastewater such as groundwater or wastewater contaminated with nitrogen compounds. One of them is a biological removal method, which converts organic nitrogen into ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen, and finally converts it into nitrogen gas. In this method, liquid is basically treated in a nitrification treatment tank or a denitrification treatment tank using nitrifying bacteria and denitrifying bacteria in activated sludge. That is, in the nitrification treatment tank, organic nitrogen can be converted to ammonia nitrogen, and the ammonia nitrogen can be further converted to nitrite nitrogen and nitrate nitrogen by nitrifying bacteria. The nitrate nitrogen or nitrite nitrogen converted in the nitrification tank is generally converted into nitrogen by a denitrifying bacterium in a denitrification tank to which a hydrogen donor has been added and released into the atmosphere. Through these processes, nitrogen compounds are removed from groundwater or sewage. At this time,
In order to increase the processing capacity, a carrier for immobilizing microorganisms made of a polyurethane foam or a jelly-like polyethylene glycol derivative disclosed in Japanese Patent Application Laid-Open No. 5-23684 is introduced into a nitrification treatment tank. Microbial densification has been attempted.

[0006]

However, the conventional method has various problems. In other words,
In the method using a polyethylene glycol derivative carrier disclosed in Japanese Patent No. 23684, the microorganisms must be immobilized on the carrier in advance, and an apparatus and the like for immobilization are required, which requires capital investment. Furthermore, the carrier of this polyethylene glycol derivative can fix nitrifying bacteria in a nitrification tank under aerobic conditions, but cannot fix denitrifying bacteria in a denitrification tank performed under anaerobic conditions. It was difficult and lacked versatility.

[0007] When a polyurethane foam is used, the disadvantage of the polyethylene glycol derivative can be compensated in that it can be used in a denitrification treatment tank, but nitrification due to lack of affinity with the microorganisms described above. The maximum nitrification rate when used in a treatment tank is 130 mg-nitrogen / l
−carrier / h, and no further improvement in processing capacity was expected. Further, in the above-described method, when the nitrogen compound in the liquid is converted, the period from the start of operation to the steady operation is long, and it is not possible to increase the throughput, which is a problem.

Accordingly, the present invention has been made in view of such a situation.
It has a large amount of microorganisms adsorbed per unit area, is inexpensive, can be used in any liquid treatment tank regardless of where it is used, and has a short period of time from the start of operation to the steady operation. A carrier for immobilization of microorganisms that does not require capital investment for immobilization of microorganisms, and a liquid with high ability to remove nitrogen compounds in liquids such as clean water and sewage by biological denitrification using it A method for converting a nitrogen compound is provided.

[0009]

Means for Solving the Problems Accordingly, the present inventors have:
As a result of diligent research for the purpose of solving the problems in the above prior art, the use of a carrier for immobilizing microorganisms having fluff on the surface increases the amount of microorganisms adsorbed on the carrier, and further increases the nitrogen compound in the liquid. Has been found to increase the ability to convert.

[0010] The carrier for immobilizing microorganisms according to the present invention is a carrier for supporting or retaining microorganisms, the carrier having a fluff on its surface. The carrier may be composed of a textile fabric or a knit. In addition, the shape of the carrier, granular, dice,
One having at least one or two or more shapes selected from a piece shape, a strip shape, a plate shape, and a band shape can be used.

[0011] In order to have the fluff on the surface of the carrier for immobilizing microorganisms composed of a fibrous fabric or knit, the purpose can be achieved by performing a raising treatment or a flocking treatment. To perform the raising treatment, a cloth such as a fiber woven fabric or a knitted fabric serving as a material of the carrier can be hooked with a wire or the like and raised. In order to perform the flocking process, an adhesive is applied to a fabric such as a fiber woven fabric or a knitted fabric, and a pile made of fibers such as polyester, nylon, or rayon, which becomes hair, is raised and fixed thereon. be able to. The thus obtained cloth subjected to the raising treatment or the flocking treatment is cut into granules, dice, pieces, strips, plates or strips to obtain a carrier for immobilizing microorganisms.

The method for converting a nitrogen compound in a liquid using the carrier for immobilizing microorganisms according to the present invention comprises the step of accommodating the carrier for immobilizing microorganisms in a liquid treatment tank under aerobic conditions together with the liquid to be treated. A method for converting a nitrogen compound in a liquid for converting a nitrogen compound in the processing liquid and the microorganism-immobilizing carrier are accommodated together with the liquid to be processed in a liquid processing tank under anaerobic conditions to convert the nitrogen compound in the liquid to be processed. This is a method for converting a nitrogen compound in a liquid to be converted.

Further, after the carrier for immobilizing microorganisms according to the present invention is accommodated in a liquid treatment tank under aerobic conditions together with the liquid to be treated to convert nitrogen compounds in the liquid to be treated, only the liquid to be treated is removed. This is a method for converting a nitrogen compound in a liquid in which a new carrier for immobilizing microorganisms is accommodated in a liquid processing tank under anaerobic conditions to convert a nitrogen compound in a liquid to be treated.

Further, the carrier for immobilizing microorganisms according to the present invention is accommodated together with the liquid to be treated in a liquid treatment tank under anaerobic conditions to convert nitrogen compounds in the liquid to be treated, and then only the liquid to be treated is removed. It is housed in a liquid processing tank under aerobic conditions together with the new carrier for immobilizing microorganisms to convert nitrogen compounds in the liquid to be processed, and further a part of the liquid to be processed is transferred to a liquid processing tank under anaerobic conditions. This is a method for converting nitrogen compounds in a liquid in which the nitrogen compounds in the liquid to be processed are converted while circulating between the liquid processing tank under aerobic conditions.

Further, tap water or sewage can be used as the liquid to be treated. When the carrier for immobilizing microorganisms having fluff on the surface according to the present invention is accommodated in a liquid treatment tank under aerobic conditions or a liquid treatment tank under anaerobic conditions together with the liquid to be treated, a large amount of microorganisms are fixed by the fluff. And the activity of the microorganism can be kept high.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The carrier for immobilizing microorganisms according to the present invention may be in the form of granules, dice, pieces, strips, plates or strips. As the material of the fiber woven fabric or knitted fabric used for the carrier for immobilizing microorganisms, either natural fibers or synthetic fibers can be used. Specific examples of natural fibers include hemp, cotton,
Specific examples of silk or hair and synthetic fibers include rayon, polyester, nylon, and acryl. In the synthetic fiber, in addition to a normal yarn filled inside, a modified cross-section yarn and a hollow fiber having a hollow inside can be used. Among these fibers, it is preferable to use hollow fibers of synthetic fibers. In any case, any type of fiber may be used as long as it can be subjected to a raising process or a flocking process.

In order to apply a raising treatment to a fiber woven fabric or a knitted fabric used for such a carrier for immobilizing microorganisms, a fabric such as a fiber woven fabric or a knitted fabric serving as a material of the carrier can be hooked with a wire or the like to be raised. For example, the wire brushing, the hair brushing, and the like described in Shinkoshi Woven Fabric Finishing Method (written by Masaki Kato, published on October 30, 1969, 6th edition (new edition), Corona Co., Ltd.)
It can be performed by mechanical brushing such as carbine random brushing.

Further, in order to perform the flocking process, an adhesive is applied to a cloth such as a fiber woven fabric or a knitted fabric, and a pile made of synthetic fibers such as nylon or rayon, which becomes hair, is raised and fixed thereon. It is what you do. For example, as a method of performing a flocking process, a handbook for dyeing processing (Jan.
This method can be performed by flocking by a spraying method, a spraying method, a mechanical method such as a vibration method, a fixed method, a semi-fixed method, a continuous method, an electrode moving method, etc. it can.

In addition, as the carrier for immobilizing microorganisms, a piled material described in Woolen Encyclopedia (by Ichiro Ohno, published on June 25, 1953, Maruzen Co., Ltd.) can be used.
Further, a material such as velvet can also be used as a carrier for immobilizing microorganisms. Further, the above-mentioned raising treatment or flocking treatment can be performed not only on one side but also on both sides of fiber woven fabric or knitted fabric.

The liquid to be treated in the present invention is a liquid containing a nitrogen compound and intended to convert the nitrogen compound into another nitrogen compound, and examples thereof include groundwater, sewage, and sewage. .

The nitrogen compound contained in the liquid to be treated in the present invention is a compound containing a nitrogen atom, such as ammonia, nitrous acid, nitric acid and the like mainly contained in a nitrification tank or a denitrification tank. Can be exemplified. Furthermore, organic nitrogen such as proteins and amino acids can also be exemplified.

The term "liquid treatment tank" means a treatment tank for converting nitrogen compounds in a liquid containing nitrogen compounds. For example, there are a septic tank used in a water treatment plant, an aeration tank used in a sewage treatment plant, a nitrification tank, a denitrification tank, and the like. When the microorganism-immobilizing carrier is accommodated in the liquid treatment tank together with the liquid to be treated, the nitrogen compound in the liquid is converted by contacting the microorganism-immobilizing carrier with the liquid to be treated, so that the conversion is facilitated. To do
It is preferable to provide a facility capable of flowing the liquid to be treated.

The nitrification tank is a liquid treatment capable of converting organic nitrogen to ammonia nitrogen, and further to nitrite nitrogen or nitrate nitrogen under nitric acid or nitrite under aerobic conditions. It is a tank. In general, the microorganisms to be subjected to nitrification are already present in the liquid treatment tank, and selection of the microorganisms is caused by limiting the supply of a carbon source, which is a nutrient of the microorganism, to the nitrification treatment tank. As a result, a large number of microorganism groups such as nitric acid bacteria or nitrite bacteria suitable for the nitrification treatment tank survive. Therefore, in this process, by contacting the carrier for microorganism immobilization characterized by having a fluff on the surface of the present invention with the liquid to be treated, the microorganisms to be subjected to nitrification treatment are immobilized on the microorganism immobilization carrier, Unprecedented processing capacity can be increased. In particular, it is preferable to accumulate and fix microorganisms having a high nitrification capacity in advance because the conversion capacity of the nitrogen compound is rapidly increased. One example of a nitrite that performs this nitrification treatment is the genus Nitrosomonas, and one example of a nitrate bacterium is the genus Nitrobacter.
Each plays an important role in the nitrification tank.

The denitrification treatment tank is used in combination with a nitrification treatment tank in sewage treatment, or used for treatment of groundwater or the like containing a large amount of nitric acid, and is carried out particularly under anaerobic conditions. By putting the carrier for immobilizing microorganisms having fluff on the surface of the present invention into the denitrification tank, the denitrifying bacteria are fixed in the same manner as the nitrification tank, and nitric acid is converted to nitrogen gas. , To remove nitrogen compounds from the liquid to be treated. At this time, when the carrier for immobilizing microorganisms is brought into contact with the liquid to be treated, it is preferable to move the liquid to be treated in order to convert the nitrogen compound. In particular, it is preferable to accumulate and fix microorganisms having a high denitrifying ability in advance since the treatment capacity quickly rises in converting nitrogen compounds. The denitrifying bacteria include the genus Pseudomonas, the genus Micrococcus, and Spirulum.
illum), Achromobacter
genus acter, Alcaligen
es) Genus, Hydrogenomonas
monas), Thiobacills (Thiobacill)
us) genus.

Further, a hydrogen donor can be supplied to the denitrification tank. For example, methanol, acetic acid,
Ethanol, acetone, glucose, methyl ethyl ketone, isopropyl alcohol and the like can be mentioned, and these hydrogen donors are to supply electrons to convert nitrite nitrogen or nitrate nitrogen into nitrogen gas (N ₂ ). .

Therefore, in the present invention, the liquid to be treated can be treated in the order of the nitrification treatment tank and the denitrification treatment tank to remove nitrogen compounds. That is, the liquid to be treated containing nitrite nitrogen or nitrate nitrogen treated in the above-mentioned nitrification treatment tank is
It is allowed to flow into a denitrification treatment tank to convert nitrite nitrogen or nitrate nitrogen into nitrogen gas to remove nitrogen compounds from the liquid to be treated. Alternatively, the liquid to be treated flowing out of the nitrification tank is allowed to flow into the sedimentation basin via a sedimentation basin between the nitrification treatment tank and the denitrification treatment tank, and then is further allowed to flow from the sedimentation basin into the denitrification treatment tank. Thus, the nitrogen compound in the liquid to be treated can be removed.

Further, according to the present invention, an aeration tank is installed in front of a nitrification tank, and a solution in which the BOD in the liquid to be treated is reduced flows into the sedimentation tank. The liquid to be treated can also flow. In addition, denitrification tank,
It is also possible to treat the liquid to be treated in the order of the nitrification tank, and to further circulate a part of the liquid to be treated in the nitrification tank to the denitrification tank. The treatment can be carried out with a precipitation tank interposed between the denitrification treatment tank and the nitrification treatment tank to remove nitrogen compounds in the liquid to be treated.

The amount of the carrier for immobilizing microorganisms according to the present invention in such a liquid treatment tank depends on the shape of the liquid treatment tank and the shape of the equipment for flowing the liquid to be treated. It is desirable that the content be 3 to 40% by volume, preferably 5 to 35% by volume, particularly preferably 15 to 30% by volume. That is, when the content is less than 3% by volume, the treatment capacity is reduced. When the content is more than 40% by volume, the liquid is excessively administered, so that the fluidity of the liquid is significantly impaired, and the efficiency is significantly reduced. Therefore, it is better to be within the above range. Also,
In the denitrification treatment tank, a carrier for immobilizing microorganisms can be packed and used like a column. In that case,
The carrier for immobilizing microorganisms is 50 to 50% of the volume of the liquid treatment tank.
100% by volume can be accommodated.

As specific examples of the liquid processing tank used in the present invention, a conventional known liquid processing tank shown in FIGS. 1 to 6 and a liquid processing tank shown in FIGS. 8 and 9 can be used. 1 and 2 show that the carrier for immobilizing microorganisms (hereinafter referred to as “carrier”) having a fluff on the surface of the present invention is in the form of granules, dice or pieces by injecting a gas into the liquid to be treated. And a liquid processing tank capable of stirring the liquid to be processed. FIG. 3 shows an example of a liquid processing tank in which the shape of the carrier is a strip, a plate, or a band and is fixed in the tank. Are circulated and come into contact with the carrier having fluff on the surface of the present invention. FIGS. 4 and 5 show examples in which the liquid to be treated is circulated by a pump to come into contact with the carrier having fluff on the surface of the present invention. 6 and 8 show a liquid processing tank in which the liquid to be processed and the carrier in the tank are agitated by circulating the liquid to be processed. In particular, the liquid processing tank shown in FIG.
And a mechanism for stirring the liquid to be treated together with the granular, dice-like or piece-like carrier.

The details of each liquid processing tank will be described below. FIG. 1 shows a bubble column type liquid treatment tank 1 with a draft tube. By supplying a gas 3 such as nitrogen gas or air from the bottom 4 of the liquid processing tank 1 inside the tank body 2, a flow by an ascending flow and a descending flow shown by arrows in the drawing occurs, and the liquid to be treated This is an example in which a nitrogen compound can be converted by contacting the carrier 5 with a granular, singular or dice-like carrier 6. In the liquid processing tank of FIG. 1, a stirring means such as a propeller may be provided in the tank body 2 to stir the liquid. Alternatively, a strip-shaped, plate-shaped, or band-shaped carrier is fixed inside the tank body 2, and the nitrogen compound of the liquid 5 can be converted by circulating only the liquid 5.

Next, FIG. 2 shows a box-shaped gas lift type liquid processing tank 1. In the liquid processing tank 1, a gas supply means 7 for supplying a gas 3 from an air compressor, a nitrogen cylinder or the like is installed in the liquid 5 to be processed, and the gas 3 such as air or nitrogen gas is sent into the liquid 5 to be processed. To process the liquid 5 under aerobic or anaerobic conditions. The liquid 5 to be treated can be taken out from the treatment liquid outlet 9 through the partition wall 8 after the nitrogen compound is converted. Also in this case, as in FIG. 1, a flow due to an upward flow or a downward flow indicated by arrows in the figure occurs, and the nitrogen compound is converted by contacting the liquid 5 to be treated with the granular, singular or dice-like carrier 6. Here is an example that you can do.

The box-shaped gas-lift type liquid processing tank 1 shown in FIG. 3 has a carrier fixed in the tank as a strip, a plate or a band. In the liquid processing tank 1, a gas supply means 7 for supplying a gas 3 from an air compressor, a nitrogen cylinder or the like is installed in the liquid 5 to be processed, and the gas 3 such as air or nitrogen gas is sent into the liquid 5 to be processed. The liquid 5 is treated under aerobic or anaerobic conditions, and the liquid 5 can be removed from the processing liquid outlet 9 through the partition wall 8 after the nitrogen compound is converted. This is the same as in FIG. Also in this case, similarly to FIG. 1, a flow is caused by an ascending flow or a descending flow indicated by arrows in the figure, and the nitrogen compound of the liquid 5 to be treated can be converted.

The liquid processing tank 1 of the descending-flow expanding type shown in FIG. 4 is used mainly under anaerobic conditions. A screen 10 is provided on the upper part of the bottom part 4, and a granular, dice-like or piece-like carrier is placed thereon. The body 6 is placed, and the liquid 5 to be treated is brought into contact with the carrier while descending. Also at this time, the reflux pipe 11 connected from the upper part of the bottom 4 of the tank body 2 is connected to the tank body 2 above the liquid level 12 of the liquid 5 to be treated in the tank body 2 via the outside of the tank. The liquid to be treated 5 is circulated through the flow path 13. When the liquid 5 to be treated comes into contact with the carrier 6, the nitrogen compound in the liquid can be converted. It is particularly effective when the apparent specific gravity of the carrier is smaller than water.

The liquid processing tank 1 of the downflow type shown in FIG. 5 is also used mainly under anaerobic conditions, in which the liquid 5 to be treated is brought into contact with the carrier 6 while being lowered. This liquid processing tank 1
A strip-shaped, plate-shaped or band-shaped carrier is fixed inside the tank body 2 to circulate the liquid 5 to be treated, and a reflux pipe 11 connected from the upper portion of the bottom 4 of the tank body 2 The liquid 5 to be treated is circulated via a pump 13 by being connected to the tank main body 2 above the liquid level 12 of the liquid 5 to be treated in the tank main body 2. Therefore, when the liquid 5 to be treated comes into contact with the carrier 6, the nitrogen compound in the liquid can be converted.

FIG. 6 shows an example in which a granular, dice-like or piece-like carrier 6 is used in the ejector-type liquid treatment tank 1. In the liquid processing tank 1, the tank main body 2 is vertically divided into two parts by a screen 10.
A reflux pipe 11 for circulating the liquid 5 to be treated by a pump 13
And a carrier recovery pipe 15 having a liquid jet mechanism 14 that merges with the reflux pipe 11 are provided outside the tank. Thus, the liquid 5 to be treated flows forcibly through the reflux pipe 11 by the pump 13 and flows into the liquid jet mechanism 14 to be a liquid jet. The liquid 5 to be processed and the carrier 6 circulating in the carrier recovery pipe 15 generate a propulsive force inside the tank body 2 by the liquid jet to perform flow stirring. By contacting the liquid 5 to be treated with the carrier 6 in this manner, the nitrogen compound in the liquid can be converted.

The principle of the liquid jet mechanism 14 used in FIG. 6 will be described with reference to FIG. A box 20 for receiving a carrier recovery tube 15 for recovering the granular, dice-like or singly-shaped carrier 6 is formed in the middle of the reflux tube 11. A narrow-diameter portion 22 having a reduced passage cross-sectional area at. Therefore, when the liquid to be treated 5 that has entered the box 20 passes through the narrow-diameter portion 22, the flow velocity is accelerated as the passage cross-sectional area is reduced. As a result of the acceleration of the flow velocity in this manner, a negative pressure is created around the narrow-diameter portion 22, and the liquid 5 containing the carrier 6 is sucked from the carrier recovery pipe 15 through the carrier recovery pipe 15.
Becomes a liquid jet.

FIG. 8 shows another example of the ejector type liquid processing tank 1 having the liquid jet mechanism 14. The liquid processing tank 1 is mainly composed of a carrier recovery pipe 15, a recirculation pipe 11 having a circulation pump 13 interposed in the middle of the pipe, and a liquid jet mechanism 14. This tank body 2
It is a cylindrical container having a bottom 4 and a lid 16, and is configured to maintain airtightness. A screen 10 for dividing the inside into two parts is provided inside the tank
Further, the granular, dice-shaped or piece-shaped carrier 6 accommodated therein is separated to prevent the carrier 6 from entering the reflux tube 11. A carrier collection pipe 15 having a carrier collection port 17 attached to the upper end is provided inside the tank body 2. The carrier recovery pipe 15 is used for the liquid level 1 of the liquid 5 to be treated.
2 and the carrier 6 and the liquid 5 to be treated.
The liquid is jetted to the outside of the tank main body 2 through the tank wall 18 and the liquid flow jet mechanism 14 returns
Has joined. The reflux pipe 11 forcibly supplies the liquid 5 to be treated inside the tank body 2 to the liquid jet mechanism 14 by the pump 13, and further flows through the carrier recovery pipe 15 which merges with the liquid jet mechanism 14. The flowing liquid 5 to be processed and the carrier 6 can be circulated by the propulsive force of the generated liquid jet. Further, inside the tank body 2, an inclined wall body 19 is provided on the entire circumference or a part around the carrier recovery port 17, and the carrier 6 floating toward the liquid surface 12 is moved to the carrier recovery port 17. It is easy to gather around.

FIG. 9 shows another example of the ejector type liquid processing tank 1 having the liquid jet mechanism 14. The liquid processing tank 1 mainly includes a circulation pipe (1) 11 having a circulation pump 13 interposed in the middle of the pipe, a circulation pipe (2) 11 'having no circulation pump, and a liquid jet mechanism 14. Have been. The tank main body 2 is a cylindrical container having a bottom 4 and a lid 16, and is configured to maintain airtightness. Inside the tank main body 2, a strip-shaped, plate-shaped or band-shaped carrier 6 is fixed. A reflux pipe (2) 11 'having a liquid inlet 17' attached to the upper end is provided inside the tank body 2, and the reflux pipe (2) 1
Reference numeral 1 'denotes another suction port for the liquid 5 to be treated, which is located below the liquid level 12 of the liquid 5 to be treated, is guided to the outside of the tank body 2 through the tank wall 18, and is provided with a liquid jet mechanism 14
At the junction with the reflux pipe (1) 11. The reflux pipe (1) 11 forcibly supplies the liquid 5 to be treated inside the tank body 2 to the liquid jet mechanism 14 by the pump 13;
Further, the liquid 5 to be treated flowing inside the recirculation pipe (2) 11 'merging with the liquid jet mechanism 14 can be circulated by the propulsive force of the generated liquid jet.

The reflux pipe 11 of FIGS. 8 and 9 is connected to the tank body 2 through the tank wall 18 as shown in FIG.
By arranging the axis of the reflux tube 11 substantially in the tangential direction of the tank wall 18, a swirling flow is generated in the liquid flow returned to the space in the tank, and the carrier 6 is sufficiently contacted.

In the liquid processing tank 1 described above, a tank body 2 having particularly high airtightness can be used. Further, a water jacket for keeping the temperature of the liquid to be treated 5 constant around the tank body 2 can be attached. Further, if necessary, a dissolved oxygen electrode and a dissolved oxygen meter for measuring the dissolved oxygen of the liquid 5 to be treated, a pH electrode and a pH meter for measuring the pH of the liquid 5 to be treated, and A supply port for supplying a system compound or the like can be provided in the lid 16 or the tank wall 18 of the tank body 2 depending on the type of the liquid 5 to be treated. In particular, as a compound that can be a hydrogen donor, methanol, ethanol, or the like can be used.
Examples of the inorganic compound include compounds that adjust the pH of the liquid 5 to be treated, such as sodium hydroxide and hydrochloric acid.

The nitrification tank and the denitrification tank of the present invention will be described in detail. The liquid treatment tank 1 shown in FIGS. 1 to 6 and FIGS. 8 and 9 can be used for the nitrification treatment tank. When treated under aerobic conditions, a group of microorganisms capable of performing nitrification treatment (hereinafter referred to as "nitrifying bacteria").
Means a liquid processing tank 1 that can be multiplied and subjected to nitrification treatment. Therefore, the principle will be described with reference to FIG.
The blower 24 is connected to the liquid, and further contains the liquid to be treated 5 containing nitrifying bacteria and the carrier 6. This carrier 6
Is contained, the nitrifying bacteria contained in the liquid 5 to be treated adhere to or bind to the carrier 6, and the blower 24 sends the air 3 into the liquid 5 to be treated, whereby the liquid 5 and the liquid 5 to be treated are mixed. The treatment liquid 5 is nitrified by increasing the contact efficiency of the carrier 6. In the case of nitrification, a pH electrode 25 is provided in the nitrification tank 23 in order to keep the pH constant.
And installing a pH meter 26, while adding an alkaline compound 27 such as sodium hydroxide as shown by an arrow, can prevent a decrease in pH and perform nitrification treatment, and keep the growth environment of the microorganisms constant. be able to. Nitrogen compounds mainly containing ammonia nitrogen (NH ₄ —N) in the liquid 5 to be treated in the nitrification tank 23 include nitrite nitrogen (NO ₂ —N) and nitrate nitrogen (NO ₃ —N). Is converted to

As for the denitrification tank 28 in FIG. 12, the liquid processing tank 1 shown in FIGS. 1 to 6, 8 and 9 can be used similarly to the nitrification tank 23. FIG.
The principle of the denitrification will be explained with reference to FIG.
8 is to treat the liquid 5 in the liquid processing tank 1 under anaerobic conditions, that is, in an oxygen-free condition.
Microorganisms (hereinafter referred to as “denitrifying bacteria”) contained therein and capable of performing a denitrification treatment propagate, and the liquid to be treated 5
Is to be processed. In particular, it is desirable that the denitrification treatment tank 28 be a closed tank that can prevent the inflow of oxygen. In the denitrification tank 28, the carrier 6 and the liquid 5 to be treated are accommodated, and the denitrifying bacteria are adsorbed or adhered to the carrier 6, and the nitrite nitrogen (NO ₂ -N), nitrate nitrogen (NO ₃ -
N) is converted into water and nitrogen gas. further,
The nitrogen gas is separated from the denitrification treatment tank 28 and released into the atmosphere. As a result, nitrogen compounds are removed from the liquid, and the denitrification treatment is performed. At this time, if necessary,
Methanol, ethanol, etc., which are also hydrogen donors, can be added and supplied to the liquid 5 to be treated. In order to improve the contact between the carrier 6 and the liquid 5 to be treated, it is desirable to provide a stirring means in the liquid 5 to be treated in the denitrification tank 28. Also,
The denitrification treatment tank 28 supplies oxygen-free gas 3 such as nitrogen gas into the liquid 5 to be treated by the gas supply means 7 through the pump 13 in order to release oxygen in the liquid 5 to be treated and maintain anaerobic conditions. By feeding, the liquid 5 to be treated can be stirred and the contact with the carrier 6 can be improved.

Further, the liquid 5 to be treated can be treated by combining the nitrification treatment tank 23 and the denitrification treatment tank 28. In this method, as shown in FIG. 13, a nitrification treatment tank 23 under aerobic conditions and a denitrification treatment tank 28 under anaerobic conditions are arranged in that order. Nitric bacteria are accommodated in the nitrification treatment tank 23 and denitrification bacteria are immobilized by adsorbing or adhering to the carrier 6 in the denitrification treatment tank 28. That is, the nitrogen compound in the liquid 5 to be treated, which has been treated in the nitrification tank 23, is changed from ammonia nitrogen (NH ₄ —N) to nitrite nitrogen (NO
₂ -N), is converted to nitrate nitrogen (NO ₃ -N).
Then, the liquid 5 to be treated is further transferred to the denitrification tank 28, and the nitrite nitrogen (NO ₂ −
N), in which nitrate nitrogen (NO ₃ -N) into a nitrogen gas. In addition, contrary to FIG. 13, the denitrification treatment tank 28 and the nitrification treatment tank 23 are arranged in this order, and the liquid 5 and the carrier 6 are accommodated in each tank in the same manner as described above, and the nitrogen compound in the liquid to be treated is removed. It can also be processed.

FIG. 14 illustrates a band-like carrier for immobilizing microorganisms. This is about 25cm wide and 1m long
This is an example in which both ends of a cut carrier are sewn to form a ring. The upper and lower ends can be fixed and inserted into the liquid processing tank. FIG. 15 illustrates a strip-shaped carrier for immobilizing microorganisms. This is about 10m wide
It is a strip-shaped carrier having a length of 30 cm and a length of 30 cm with a twist. This can also be inserted into the liquid treatment tank by connecting strip-shaped carriers and fixing the upper and lower ends thereof.

[0045]

Next, the details of the present invention will be described based on embodiments. (Production Example 1) A knitted material serving as a carrier base was prepared by circular knitting using a 75 denier polyester processed yarn as a core yarn, and a 35 denier polyester hollow yarn as an upper yarn and a lower yarn to be raised, and this was subjected to a conventional method. After performing the opening and refining, the brushing treatment is performed seven times on one side with a needle cloth raising machine, the shearing and setting are performed, and the target double-sided raising cloth (width 150 cm × 30 m, basis weight 250 g / m ² , brushing) 2.5 mm in length).

(Example 1) The raised cloth of Production Example 1 was applied to a width 25c.
m and a length of 1 m, and both ends were sewn to obtain a band-like carrier for immobilizing microorganisms as shown in FIG.

(Example 2) The raised cloth of Production Example 1 was 10 m in width.
m and 30 cm in length to obtain a strip-shaped carrier for immobilizing microorganisms as shown in FIG.

Example 3 The brushed fabric of Production Example 1 was cut so that the length of one side was 5 mm to obtain a die-shaped carrier for immobilizing microorganisms.

(Example 4) An artificial inorganic synthetic wastewater having a wastewater composition shown in Table 1 (1) using a box-shaped gas lift type liquid treatment tank having a capacity of 30 liters shown in FIG.
Was prepared and the activated sludge was adsorbed and immobilized on the strip-shaped carrier for immobilizing microorganisms obtained in Example 1, and then the filling rate was 15%.
The liquid to be treated, which has been adjusted so that the ammonium nitrogen (NH ₄ —N) content of the artificial inorganic synthetic wastewater (1) becomes 500 ppm with ammonium chloride, continuously flows into the liquid treatment tank. Was converted to nitrate nitrogen. At this time, the temperature of the liquid to be treated was 30 ° C., the pH was 7.5 to 8.5, and the volume load was as shown in Table 2. The analysis of water quality was based on JIS K0102-1993. As shown in FIG. 16, the change in the concentration of ammonia nitrogen (NH ₄ —N) in the effluent solution during the test period was 0.5 k
g-Nitrogen / m ³ -Liquid treatment tank / day to 1.5 kg-Nitrogen / m ³ -Liquid treatment tank / day
Even after days, the removal rate of ammonia nitrogen is about 80%
It was able to maintain above. The nitrification rate of the carrier is 330
mg-nitrogen / l-carrier / h or more.

[0050]

[Table 1]

[0051]

[Table 2]

Example 5 A test was performed in the same manner as in Example 4 except that the content of ammonia nitrogen (NH ₄ —N) in the synthetic inorganic synthetic wastewater (1) was adjusted to 50 ppm. At this time, the temperature of the liquid to be treated is 30 ° C., and the pH is 7.
5 to 8.5, and the volume load was as shown in Table 3. Ammonia nitrogen (NH ₄ −) in the effluent solution during the test period
As shown in FIG. 17, the change in the concentration of N) was as follows: the volume load was changed from 0.05 kg-nitrogen / m ³ -liquid treatment tank / day to
Despite the increase of 0 kg-nitrogen / m ³ -liquid treatment tank / day, the removal rate of ammonia nitrogen was maintained at 90% or more even after 200 days. The nitrification rate of the carrier is 250
mg-nitrogen / l-carrier / h or more.

[0053]

[Table 3]

(Example 6) An artificial inorganic synthetic wastewater (1) having a wastewater composition shown in Table 1 was prepared by using a box-shaped gas lift type liquid treatment tank having a capacity of 1.4 liters shown in FIG. 2 as a nitrification treatment tank. Then, after adsorbing and immobilizing activated sludge on the dice-like carrier for immobilizing microorganisms obtained in Example 3,
The tank is filled at a filling rate of 20%, and ammonium chloride (NH ₄ −) of the artificial inorganic synthetic wastewater (1) is filled with ammonium chloride.
N) The liquid to be treated whose content was adjusted to 500 ppm was continuously flowed into the liquid treatment tank and converted into nitrate nitrogen. At this time, the temperature of the liquid to be treated is 30 ° C., and the pH is 7.5.
８8.5, and the volume loading was as shown in Table 4. In addition,
The analysis of water quality was based on JIS K0102-1993. As shown in FIG. 18, the change in the concentration of ammonia nitrogen (NH ₄ —N) during the test period was as follows.
g-Nitrogen / m ³ -Liquid treatment tank / day to 0.8 kg-Nitrogen / m ³ -Liquid treatment tank / day
Even after 0 days, the removal rate of ammonia nitrogen is 90%
Maintained above.

[0055]

[Table 4]

(Example 7) An artificial inorganic synthetic wastewater with a wastewater composition shown in Table 5 using an ejector type liquid treatment tank having a capacity of 15 liters shown in FIG. 9 as a denitrification treatment tank (2)
And the strip-shaped carrier for immobilizing microorganisms obtained in Example 2 is fixed to a frame as shown in FIG. 15, and the activated sludge is adsorbed and immobilized, and then filled into a tank at a filling rate of 18%. Nitrate nitrogen (NO ₃ −) of artificial inorganic synthetic wastewater (2) by nitric acid
N) The liquid to be treated whose content was adjusted to 500 ppm was continuously flowed into the liquid treatment tank to perform a denitrification treatment.
At this time, methanol was added as a hydrogen donor, and the concentration was maintained at 1430 mg / l. The temperature of the liquid to be treated was 30 ° C., the pH was 7.5 to 8.5, and the volume load was as shown in Table 6. The analysis of water quality was conducted according to JIS K0
102-1993. As shown in FIG. 19, the change in the concentration of nitrate nitrogen (NO ₃ -N) in the effluent during the test period was 0.5 kg-nitrogen / m ³ -8.0 kg from the liquid treatment tank / day. Even after 200 days, the removal rate of nitrate nitrogen was maintained at about 90% or more despite the increase in nitrogen / m ³ -liquid treatment tank / day. The denitrification rate of the carrier was 1700 mg-nitrogen / l-carrier / h or more.

[0057]

[Table 5]

[0058]

[Table 6]

(Embodiment 8) A capacity of 15 liters shown in FIG.
Ejector type liquid treatment tank used as denitrification treatment tank
The artificial inorganic synthetic wastewater with the wastewater composition shown in Table 5 (2)
And a dice-like microbe obtained according to Example 3.
After the activated sludge is absorbed and immobilized on the material immobilization carrier,
Filling the tank with 20%, artificial inorganic synthetic wastewater with nitric acid
(2) nitrate nitrogen (NO_Three-N) 500pp content
m into the liquid processing tank.
A denitrification treatment was performed. At this time, meta as a hydrogen donor
And maintained the concentration at 1430 mg / l.
Was. The temperature of the liquid to be treated is 30 ° C., and the pH is 7.5 to 8.0.
5. The volume load was as shown in Table 7. The quality of the water
The analysis was based on JIS K0102-1993. test
Nitrate nitrogen (NO _Three−N) is shown in FIG.
As shown in the figure, the volume load was 0.5 kg-nitrogen / m ^Three−
7.0kg-Nitrogen / m from liquid treatment tank / day^Three-Liquid treatment
After 200 days despite increased tanks / day
Also maintained the nitrate nitrogen removal rate at about 90% or more. Responsible
The body's denitrification rate is 1300mg-nitrogen / l-carrie
r / h was exceeded.

[0060]

[Table 7]

[0061]

According to the carrier for immobilizing microorganisms of the present invention,
By having fluff on the surface, a large amount of microorganisms can be carried or held by the fluff and immobilized.
Therefore, by accommodating the carrier for immobilizing microorganisms in a liquid treatment tank under aerobic conditions, for example, a nitrification treatment tank, together with the liquid to be treated, the nitrogen compound in the liquid to be treated, for example, ammonia nitrogen, is converted into nitrate nitrogen. Can be efficiently converted to In addition, by accommodating the carrier for immobilizing microorganisms in a liquid treatment tank under anaerobic conditions, for example, a denitrification treatment tank together with the liquid to be treated, nitrogen compounds in the liquid to be treated, for example, nitrate nitrogen, can be efficiently removed. Nitrogen treatment can be performed. In these treatments, the carrier for immobilizing microorganisms can immobilize a large amount of microorganisms, so that the nitrogen conversion treatment in a nitrification treatment tank or a denitrification treatment tank is quickly started, the activity of the microorganisms is rapidly increased, and the activity is increased. Can be maintained, so that the treatment capacity of a water treatment plant, a sewage treatment plant, and the like can be improved.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a bubble column type liquid treatment tank with a draft tube.

FIG. 2 is an explanatory view of a box-shaped gas lift type liquid processing tank.

FIG. 3 is an explanatory view of another example of a box-shaped gas lift type liquid processing tank.

FIG. 4 is an explanatory view of a descending-flow expanding type liquid processing tank.

FIG. 5 is an explanatory view of a downward flow type liquid processing tank.

FIG. 6 is an explanatory view of an ejector type liquid processing tank.

FIG. 7 is an explanatory view of a liquid jet mechanism.

FIG. 8 is an explanatory diagram of another example of an ejector-type liquid processing tank.

FIG. 9 is an explanatory view of another example of an ejector-type liquid processing tank.

FIG. 10 is a plan view of the ejector-type liquid processing tank shown in FIGS. 8 and 9;

FIG. 11 is an explanatory view of a liquid treatment tank used as a nitrification treatment tank.

FIG. 12 is an explanatory view of a liquid treatment tank used as a denitrification treatment tank.

FIG. 13 is an explanatory view of a liquid treatment tank using both a nitrification treatment tank and a denitrification treatment tank.

FIG. 14 is an explanatory view of a belt-like carrier for immobilizing microorganisms.

FIG. 15 is an explanatory view of a strip-shaped carrier for immobilizing microorganisms.

FIG. 16: Change over time of ammonia nitrogen in liquid (1)

FIG. 17: Change over time of ammonia nitrogen in liquid (2)

FIG. 18: Change over time of ammonia nitrogen in liquid (3)

FIG. 19: Change over time of nitrate nitrogen in liquid (1)

FIG. 20: Change over time of nitrate nitrogen in liquid (2)

[Explanation of symbols]

1. Liquid treatment tank 15. Carrier recovery tube 2. Tank body 16. Lid 3. Gas 17. Carrier recovery port 4. Bottom 17 '.
4. Liquid intake Liquid to be treated 18. Tank wall 6. Carrier 19. Inclined wall body 7. Gas supply means 20. Box 8. Partition wall 21. Outer end of tank 9. Processing liquid outlet 22. Narrow diameter part 10. Screen 23. Nitrification tank 11. Reflux pipe (1) 24. Blower 11 '. Reflux tube (2) 25. p
H electrode 12. Liquid level 26. p
H meter 13. Pump 27. Compound 14. Liquid jet mechanism 28. Denitrification tank

Continued on the front page (51) Int.Cl. ⁶ Identification number Reference number in the agency FI Technical display location C12N 11/02 C12N 11/02

Claims (8)

[Claims] 1. A carrier for immobilizing microorganisms, which is a carrier for supporting or holding microorganisms, wherein the carrier has fluff on its surface. 2. The carrier for immobilizing microorganisms according to claim 1, wherein the carrier comprises a fiber woven or knitted fabric. 3. The method according to claim 2, wherein the carrier is in the form of granules, dice, pieces,
The carrier for immobilizing microorganisms according to claim 1 or 2, wherein the carrier has at least one or two or more shapes selected from a strip shape, a plate shape, and a band shape. 4. The carrier for immobilizing microorganisms according to any one of claims 1 to 3 is accommodated in a liquid treatment tank under aerobic conditions together with the liquid to be treated, and nitrogen compounds in the liquid to be treated are removed. A method for converting a nitrogen compound in a liquid to be converted. 5. The carrier for immobilizing microorganisms according to any one of claims 1 to 3 is accommodated in a liquid treatment tank under anaerobic conditions together with the liquid to be treated, and the nitrogen compound in the liquid to be treated is converted. For converting nitrogen compounds in liquids to be converted. 6. The carrier for immobilizing microorganisms according to any one of claims 1 to 3 is accommodated together with the liquid to be treated in a liquid treatment tank under aerobic conditions to convert nitrogen compounds in the liquid to be treated. A method for converting a nitrogen compound in a liquid, wherein only the liquid to be treated is accommodated in a liquid treatment tank under anaerobic conditions together with a new carrier for immobilizing microorganisms to convert the nitrogen compound in the liquid to be treated. 7. The carrier for immobilizing microorganisms according to any one of claims 1 to 3 is accommodated together with the liquid to be treated in a liquid treatment tank under anaerobic conditions to convert nitrogen compounds in the liquid to be treated. After that, only the liquid to be treated is accommodated in a liquid treatment tank under aerobic conditions together with the new carrier for immobilizing microorganisms, to convert nitrogen compounds in the liquid to be treated, and further to a part of the liquid to be treated. A method for converting a nitrogen compound in a liquid, wherein the liquid compound is returned to a liquid processing tank under anaerobic conditions and circulated between the liquid processing tank under aerobic conditions and a nitrogen compound in the liquid to be processed. 8. The method for converting a nitrogen compound in a liquid according to at least one of claims 4 to 7, wherein the liquid to be treated is tap water or sewage.