JP2003071480A - Water purification method and apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluidized bed method in which a carrier for purifying water using microorganisms in which a carrier is moved has a significantly reduced amount of excess sludge during continuous high-load operation, and has a long-term and stable The purpose is to maintain the improved wastewater treatment performance. SOLUTION: This invention uses a granulated porous ceramic having SiO ₂ and Al ₂ O ₃ as main components and a mixture of a granular carbon component as a carrier for microorganisms, and supplies oxygen-containing gas. without supplying lower or gas, and purification method of the water comprising contacting the water and the carrier to be purified in a state for flowing the carrier, SiO ₂ and a
The water to be purified is flowed upward in a fluidized bed treatment tower filled with a carrier obtained by granulating a porous ceramic having l ₂ O ₃ as a main component and a mixture of granular carbon components as a carrier. The object is achieved by a water purifying apparatus characterized by providing a water supply means for supplying water and a gas supply means containing oxygen.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention aims to treat industrial wastewater, domestic wastewater, wastewater containing other organic substances, and BOD, COD, etc. in the treatment liquid of those wastewater with high efficiency and high level. The present invention relates to a method and a device for purifying fresh water.

[0002]

2. Description of the Related Art Conventionally, various methods have been studied and implemented as a method for purifying various industrial wastewater and domestic wastewater generated from households. That is, physical treatment methods such as filtration, precipitation and adsorption, physicochemical treatment methods such as oxidative decomposition using ozone, hydrogen peroxide, and ultraviolet light, biological treatment methods such as activated sludge method and biofilm treatment method, etc. is there. Among these methods, the biological treatment method is most prevalent because of its low cost compared to other methods and its applicability from small scale to large scale.

Among the biological treatment methods, the biofilm treatment method is (1) capable of high-load operation as compared with the activated sludge method,
(2) Excellent quality of treated water, (3) Low BO
In recent years, the number of applications is increasing because it has the advantage of being able to treat D wastewater (for example, 50 ppm or less).

The biofilm treatment method includes a fixed bed method in which the carrier to which microorganisms adhere does not move, a fluidized bed method in which the carrier moves, and a three-phase fluidized bed method. It is known that in a high-load operation, the fixed bed method is likely to be clogged, whereas the fluidized bed method or the like in which a carrier moves is less likely to be clogged, which is advantageous. In the fluidized bed method, a granular biofilm carrier is packed in a treatment tower and the carrier is fluidized by an upward flow of water. In the three-phase fluidized bed method, a granular biofilm carrier is put in a treatment tank and air is diffused from the bottom surface to fluidize the carrier.

Carriers used for biofilm treatment are known to have various shapes such as plate-like, granular and string-like, and various known materials such as anthracite, sand, ceramics, plastic and activated carbon. Has been. Also known is a method of using a plurality of types of carriers in combination. For example, a method of using porous ceramics and activated carbon in combination is disclosed in JP-A-62-62.
No. 11596, the present invention uses porous ceramics and activated carbon as a fixed bed.

[0006]

In biofilm treatment, pollutants in wastewater are adsorbed and decomposed by microorganisms, and the pollutants are converted into microbial sludge. As a result, the concentration of microorganisms usually increases. Excessive microorganisms are discharged as excess sludge in order to maintain the concentration of microorganisms at an appropriate value. In the case of biofilm treatment,
As a result of the microorganisms attached to the carrier treating the pollutant components, the biofilm becomes enlarged. The enlarged biofilm is peeled off by backwashing and discharged as excess sludge. The disposal cost of the surplus sludge that was generated was a factor that increased the running cost in biofilm treatment.

Further, the growth and enlargement of the biofilm is inevitable in the conventional biofilm treatment, but various problems have been pointed out. For example, in the fluidized bed method, although the biofilm is more easily peeled off than in the fixed bed method, the biofilm swells, and the outflow of the carrier that is easily floated due to the swelling of the biofilm and a plurality of carriers attached to form a large mass. There was a problem that the processing performance was lowered due to the deterioration of the fluidity after the preparation, and the blocking by the biofilm. In addition, operations such as backwashing and separation of generated excess sludge are required, which is a factor that complicates maintenance and complicates the device.

Further, although the fluidized bed method is a highly efficient treatment method, the source of oxygen required for biological treatment is usually dissolved oxygen in water, and it is considered that the treatment rate is restricted as the load becomes higher.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems and is intended to improve it. In the biofilm treatment method of the present invention, the generation of microorganisms is suppressed, and the biofilm is enlarged. It was completed by finding a method for highly efficient purification of wastewater without causing problems such as the generation of a large amount of excess sludge.

That is, the invention of the method is SiO ₂ and Al ₂ O ₃
Granular porous ceramics containing as a main component and a mixture of granular carbon content are used as a carrier for microorganisms, and water to be purified and the microorganisms in the carrier are brought into contact with each other in a state in which the carrier is fluidized. The water purification method is characterized by using 10% by volume to 80% by volume as the porous ceramics and 20% by volume to 90% by volume as the carbon content. In addition, the carrier is made to flow under the supply of fine bubbles of a gas containing oxygen, and the gas containing oxygen is a gas containing air and a concentration of oxygen higher than that of air, and is supplied under the supply of the fine bubbles. The porous ceramic carrier is formed by adding a pore-forming material to two or more kinds selected from clay, silica stone or aluminum hydroxide and firing the mixture. It is characterized by doing.

Next, in the invention of the device, SiO ₂ and Al ₂ O _{3 are used.}
In a fluidized bed treatment tower filled with granular carbon and a mixture of granular carbon as a carrier, water for purifying water to be purified is supplied in an upward flow. A water purifier characterized by having a supply means installed. 10% by volume as porous ceramics
˜80% by volume and 20% by volume to 90% by volume as carbon content, and a means for supplying fine bubbles of a gas containing oxygen is installed.

Further, the gas containing oxygen is air or a gas containing oxygen at a concentration higher than that of air, and the carrier of the porous ceramic is two or more kinds selected from clay, silica stone or aluminum hydroxide. It is obtained by adding a pore forming material and firing and molding.

In the above invention, the ratio of the porous ceramics and the carbon content is described. However, due to the characteristics of the carrier of this kind, it is not impossible to use values other than the above-mentioned values, and it is a value that is about this value. For example, even if the proportion of the porous ceramics is 9% by volume or 81% by volume, there is almost the same effect as 10% by volume or 80% by volume.

According to the present invention, when a mixture of porous ceramics and activated carbon is used as a biofilm carrier and aerobic biotreatment is carried out while flowing the mixture, the biotreatment is carried out in a state in which the growth of microorganisms is suppressed. It was made based on the knowledge that it is possible.

That is, when a mixture of porous ceramics and activated carbon is used as a carrier for a fluidized bed, the BOD load is about 1 k.
Up to g / (m ³ · day), biological treatment could be performed with almost no excess sludge generated.

Although the detailed mechanism for suppressing the generation of excess sludge has not been clarified yet, it is presumed that the contact effect between the porous ceramics and carbon causes the suppressing effect.

Further, the present inventors have found that when the waste water containing fine bubbles of air or oxygen-enriched air is circulated so as to come into contact with the filter bed of the fluidized bed, the treatment rate of the waste water is increased. There is.

The porous ceramic used in the present invention is a porous ceramic containing SiO ₂ and Al ₂ O ₃ as main components. An example of the manufacturing method is described below,
The method is not limited to this.

As an example of the method for producing the porous ceramics used in the present invention, a mixture of two or more kinds selected from clay, silica and aluminum hydroxide is added with sawdust, chaff, etc. and water as a bubble forming material. Then, the mixture is dried, and the mixture is dried in a block state or in another suitable shape, and then fired, whereby the cell-forming material disappears to form a porous portion.

For example, when the above three components are used, clay is 20% by weight to 70% by weight, silica stone is 70% by weight to 20% by weight, and aluminum hydroxide is 10% by weight.
100 parts by weight to 140 parts by weight of sawdust and water are added to and mixed with each other by weight, and the mixture is molded into a suitable shape such as a block state and dried to a certain state by natural drying or forced drying, Porous ceramics containing SiO ₂ and Al ₂ O ₃ as main components are produced by firing at 1000 ° C. or higher.

The firing temperature is 1050 ° C. to 1350 ° C.
Is preferable, and 1200 to 1300 ° C is more preferable.

[0022] Here, the SiO ₂ 80 wt% to 45 wt%, preferably includes an _Al 2 _{O 3} 15 wt% to 40 wt%, each of the lower limit value or SiO ₂ is 45 wt%
Hereinafter, if Al ₂ O ₃ is 15% by weight or less, a porous ceramic suitable for the present invention cannot be prepared. It has been found that SiO ₂ of 80% by weight or more and Al ₂ O ₃ of 40% by weight or more are not preferable for the same reason.

The flow in the present invention means a state in which one or both of the porous ceramic and the carbon move to come into contact with each other. As a concrete method, a fluidized bed method in which a mixture of porous ceramics and carbon is filled (about 30% of the volume) by a upward flow of water from the bottom to cause the mixture to flow, and the mixture is filled The method of moving the mixture by aeration from the lower part of the treated tower, the method of moving the mixture by agitation of the tank containing the mixture (mechanical agitation or agitation by aeration) can be used. Are not limited to these methods as long as they move almost uniformly.

The mixing ratio of the porous ceramics and carbon in the present invention is preferably about 10% by volume to about 80% by volume as the porous ceramics, about 20% by volume to about 90% by volume as the carbon content, and more preferably porous. About 20% by volume to about 70% by volume as ceramics and about 3 as carbon content
0% by volume to about 80% by volume is used. If the mixing ratio does not fall within this range, the effect of suppressing microbial growth may be low.

As carbon, activated carbon, lignite, bone charcoal, charcoal, anthracite and the like are preferable, but activated carbon is more preferable. The shape of the porous ceramics and carbon is preferably granular, and the shape may be spherical, crushed, or any other shape, but care should be taken to prevent crushing into powder.

The average particle diameter of the porous ceramics and carbon is preferably about 0.1 to 4 mm in order to smoothly flow, but more preferably 0.5 to 2 mm in which few fine particles easily flow out.

The average bubble diameter of the fine bubbles used in the present invention is preferably about 500 μ or less, and the finer it is, the more preferable it is (for example, several μ). However, considering the apparatus and cost for forming the fine bubbles, 10 ~ 100μ seems to be a range that is easy to apply. When the bubbles are larger than 500 μ, the flow of the carrier in the fluidized bed is disturbed or the carrier jumps up, which may cause the carrier to be easily worn.

When fine bubbles coexist, the ratio of the gas flow rate (Vg 1 / min) and the liquid flow rate (Vl 1 / min) flowing into the processing tank, the gas-liquid flow rate ratio (Vg / Vl).
Is preferably 0.01 to 0.2, more preferably 0.03 to 0.1.

Any method may be used to generate the fine bubbles. For example, a method of sucking gas into a water circulation pump, stirring the gas in the pump, discharging the gas from the pump, and then mixing with a static mixer, a liquid circulation pipe A method in which an ejector is provided in the middle of the process to draw in air is simple and preferable for the present invention.

The oxygen-enriched air used in the present invention is, for example, an oxygen-enriched film or PSA (Pressure Swing Adsorption).
It is made of, but is not limited to, a device using oxygen, an oxygen cylinder, or the like. For example, when an oxygen-enriched membrane is used, a gas having an oxygen concentration of 30% or more can be easily produced with pressurized air of 4 to 5 atm. Enrichment of oxygen, oxygen concentration 5
0% or less is preferable.

The reason why the treatment rate is increased by contacting the waste water containing fine bubbles with the carrier in the fluidized bed is not clear yet, but the direct contact between the fine bubbles and the microorganisms, the activated carbon from the fine bubbles to oxygen. It can be speculated that the absorption rate of oxygen increases the supply rate of oxygen required by the microorganisms.

As an example of the apparatus of the present invention, there is a fluidized bed apparatus in which granular porous ceramics and carbon are packed in a treatment tower and the carrier is made to flow in an upward flow of water. Since it is suppressed, stable operation without obstruction is achieved with a device having a simple structure.

An example of the fluidized bed apparatus is as follows. A circular flow outlet and a backwash diffuser are provided at the bottom of the cylindrical treatment tower, and a mesh screen (0.5-2 mm) for preventing carrier outflow is attached to the top of the treatment tower. The liquid is circulated from the circulation outlet to the bottom outlet. The wastewater (raw water) to be treated is made to flow into the upper part of the treatment tower near the circulation outlet, and the treated water is discharged from the outlet at the top of the treatment tower.

When the dissolved oxygen in the waste water is insufficient, an aeration pipe for aeration can be provided above the treatment tower.

Further, the treatment tower is packed with granular porous ceramics and carbon as a microorganism carrier, but the carrier volume is about 1
It is customary to lay a 0% to 20% support bed at the bottom of the treatment tower. The support bed may be of any size such as stone, ceramics, activated carbon and the like, which has a larger particle size and is not light. The amount of the microbial carrier is preferably 15% to 50% of the liquid volume in the processing tower, more preferably 20% to 40%.

As an example of an apparatus for coexisting fine bubbles, as a circulation pump, gas is sucked, stirred in the pump, discharged from the pump, and then mixed by a static mixer to obtain fine bubbles (average bubble diameter 50 μm). ) Can be used.

As an example of a device for producing oxygen-enriched air, a hollow filter and a compressor can be used. By passing 4 atm of air pressurized by a compressor through the filter, an oxygen-enriched gas having an oxygen concentration of 31% is obtained.

[0038]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to SiO ₂ and Al ₂ O.
_{Using a} mixture of a granular material of porous ceramics containing ₃ as a main component and granular carbon content as a carrier for microorganisms,
Water is purified by bringing the carrier into contact with water to be purified, wherein the amount of the porous ceramics is 10% by volume to 80% by volume and the carbon content is 20% by volume to 9%.
0% by volume, and the particle size of the carrier was 4 mm or less.

The volume of the porous ceramic and the carbon content in the fluidized bed treatment tower is 20% to 40%, and the carrier is fluidized and stirred by the upward flow of water to achieve uniform contact. Further, air or high concentration oxygen fine bubbles containing a large amount of oxygen are used.

In the apparatus of the present invention, the above-mentioned porous ceramics and carbon are mixed in a constant ratio in a conventional fluidized bed treatment tower and accommodated at a predetermined volume ratio (about 20% -40%), and water is sent. , That was sent.

[0041]

Example 1 (A) Porous ceramics (firing temperature 13
Example for inhibiting bacterial growth by flowing a mixture of (00 ° C.) and activated carbon.

For the porous ceramics, a mixture of clay, silica stone and aluminum hydroxide is added and mixed with sawdust and water as a bubble forming material, and the mixture is dried in a block state and then fired at 1300 ° C. Prepared. The contents (% by weight) of SiO ₂ and Al ₂ O _{3 in} the porous ceramics were 69% and 21%, respectively. The other components and contents (% by weight) were as follows.

Fe ₂ O 0.80% K ₂ O 0.93% CaO 0.45% MgO 2.50% Na ₂ O 0.35% TiO ₂ 0.30%

The porosity was 82% and the bulk specific gravity was 0.35. Crush this porous ceramics to 1-2 mm
It was used after classification. The activated carbon used had a particle size of about 1 mm.

A mixture of 5 ml each of dry heat sterilized porous ceramics and activated carbon was placed in a 200 ml Erlenmeyer flask. Sodium acetate was added to the TOC (Tota) solution in a pH 7 phosphate buffer (containing ammonium salt) prepared with tap water.
l Organic Carbon; 400 mg / l as total organic carbon
The dissolved solution was autoclaved and 100 ml of the solution was added to the Erlenmeyer flask. An inoculum suspension was added to this so that the inoculum (Pseudomonas aeruginosa) was 10 ³ cells / ml. The number of inoculated bacteria was determined from the luminescence intensity of the liquid by utilizing the fact that the viable cell count of a plate medium and the chemiluminescence intensity of ATP are correlated. After adding the inoculum, the mixture was shaken (125 rpm) at 25 ° C.

(B) Porous ceramics (firing temperature 11
Example for inhibiting bacterial growth by flowing a mixture of (00 ° C.) and activated carbon.

The same procedure as in Example 1 (A) was performed except that a porous ceramic having a firing temperature of 1100 ° C. was used. The contents of SiO ₂ and Al ₂ O _{3 in} the porous ceramics were 69% and 21%, respectively.

Other components and contents (% by weight) were as follows.

Fe ₂ O 0.81% K ₂ O 0.92% CaO 0.43% MgO 2.70% Na ₂ O 0.35% TiO ₂ 0.30%

The porosity was 80% and the bulk specific gravity was 0.40.

Table 1 shows the results of examining the number of bacteria on the carrier every 10 days for 40 days after the start of shaking in each of Examples (A) and (B). The results of examining the viable cell count in the liquid are shown in Table-2.

[0052]

Comparative Example 1 The procedure of Example 1 was repeated, except that no shaking was performed. The results are shown in Table-1 and Table-2.

[0053]

Comparative Example 2 (A) When only porous ceramics is used as a carrier.

The same procedure as in Example 1 was carried out except that only porous ceramics was used as the microorganism carrier.

(B) When only activated carbon is used as a carrier.

The same procedure as in Example 1 was carried out except that only activated carbon was used as the microorganism carrier.

The results are shown in Tables 1 and 2.

[0058]

[Table 1]

The indication <10 ² in the table indicates that the detection limit value of viable cell count by chemiluminescence intensity of ATP is 10 ² or less.

The unit of the numerical value of the viable cell count in Table 1 is the unit / g.
-A carrier.

[0061]

[Table 2]

The indication <10 ² in the table indicates that the detection limit value of viable cell count by the chemiluminescence intensity of ATP is 10 ² or less. The unit of the numerical value of the viable cell count in Table 2 is cells / ml.

By shaking the flask in Example 1 and Comparative Example 2, the carrier in the flask is in a fluidized state. From Example 1 and Comparative Example 1, it can be seen that the growth of microorganisms is suppressed in the state where the mixture of porous ceramics and activated carbon is flowing. It can be seen that the inhibition of microbial growth occurs in both porous ceramics and activated carbon.

From the comparison between Example 1 and Comparative Example 2, it can be seen that the porous ceramics and the activated carbon alone do not have the effect of suppressing the growth of microorganisms.

The firing temperature of the porous ceramics is 1300.
Both ℃ and 1100 ℃ showed a microbial growth inhibitory effect when mixing and flowing porous ceramics and activated carbon, but at 1300 ℃, microbial growth inhibitory effect is stronger than 1100 ℃ I understand.

[0066]

Example 2 Example of decolorization of activated sludge treatment liquid of swine farm wastewater by a fluidized bed using a mixture of porous ceramics and activated carbon as a carrier.

(A) In the case where fine bubbles do not coexist.

The treated liquid obtained by treating the swine farm wastewater with activated sludge was filtered through a hollow fiber to remove the suspension, and used as raw water. Raw water quality is BOD 40mg / l, COD
Mn 350 mg / l, DOC (carbon concentration derived from dissolved organic matter) 210 mg / l, absorbance at 400 nm was 1.5, and it was brown.

10 l / day of raw water (HRT (retention time of liquid) for 1 day) was placed in a fluidized bed treatment tower (liquid volume: 10 l) packed with a mixture of porous ceramics (similar to Example 1 (A)) and activated carbon. It was made to flow in and was processed. Particle size 1-2 in the processing tower
mm porous ceramic and activated carbon in volume ratio 3: 7
3 l of the mixture mixed in was charged. Gravel with a particle size of 5 to 10 mm was laid as a support bed at the bottom of the treatment tower.

The treatment tower is cylindrical, a discharge port for circulating flow and a backwash diffuser are provided at the bottom of the treatment tower, and a mesh screen (0.8 mm) for preventing carrier outflow is attached to the top of the treatment tower.
A circulation pump is used to circulate the liquid from the circulation outlet at the top of the processing tower to the discharge port at the bottom. Wastewater treated (raw water)
Is made to flow into the upper part of the treatment tower near the circulation outlet, and the treated water is discharged from the top outlet of the treatment tower. Aeration was performed by installing an air diffuser on the upper part of the treatment tower.

Backwashing was performed by sending air to the backwash diffuser at the bottom of the treatment tower every 3 days.

The water quality of the treated water after 2 months was 4 m of BOD.
g / l, CODMn 27 mg / l, DOC 16 mg
/ L, the absorbance at 400 nm was less than 0.1 and was almost colorless. The results are shown in Table-3.

(B) Example in which fine air bubbles coexist.

20 l of raw water was mixed with fine air bubbles.
Example 2 except that the inflow was carried out every day / day (0.5 days for HRT).
It carried out like (A).

Fine air bubbles were generated by sucking the gas into a circulation pump (Nikuni pump), stirring the gas in the pump, discharging the gas from the pump, and then mixing with a static mixer (average bubble diameter 50 to 100 μm).

Gas flow rate (Vgl /
min) to the liquid flow rate (Vl 1 / min) and the gas-liquid flow rate ratio (Vg / Vl) were 0.05. The results are shown in Table-3.

(C) Example in the case of coexistence of fine bubbles of oxygen-enriched gas.

The same procedure as in Example 2 (B) was carried out except that fine bubbles of oxygen-enriched gas were allowed to coexist.

As for the oxygen-enriched gas, a gas containing 90% by volume of oxygen generated by a PSA oxygen generator was mixed with air to form a gas containing 40% of oxygen. The results are shown in Table-3.

[0080]

[Comparative Example 3] Decolorization of an activated sludge treatment liquid of a pig farm wastewater by a fluidized bed using activated carbon as a carrier.

Example 2 except that activated carbon was used as the carrier
It carried out like (A).

The results are shown in Table 3.

[0083]

[Table 3]

From Examples 2 (A), (B) and (C) and Comparative Example 3, when the mixture of porous ceramics and activated carbon was used as the carrier of the fluidized bed, the amount of sludge generated was the case when activated carbon was used. It can be seen that the amount is extremely small, around 10%.

From Example 2 (A) and Comparative Example 3, it is better to use a mixture of porous ceramics and activated carbon as a carrier.
It can be seen that the effect of reducing DOC and the absorbance (color) is higher than the case of using only activated carbon.

From a comparison between Example 2 (A) and Example 2 (B), it can be seen that when a mixture of porous ceramics and activated carbon is used as a carrier, coexistence of fine bubbles increases the treatment efficiency. That is, although the treatment time was halved, it was possible to obtain treated water having a better water quality than when the fine bubbles were not used.

Further, comparing Example 2 (B) with Example 2 (C), when a mixture of porous ceramics and activated carbon is used as a carrier, it is more preferable to use oxygen-enriched gas as fine bubbles. It can be seen that treated water of water quality can be obtained.

[0088]

[Embodiment 3] An embodiment of the present invention will be described with reference to FIG.

A support bed 11 is provided at the lower inside of the processing tower 1,
A fluidized bed 12 is housed above the support bed 11. The fluidized bed 12 accommodates 30% to 40% of the volume of the processing tower 1. A drainage chamber 25 with a screen 10 for preventing carrier outflow is provided above the treatment tower 1. Further, the tip end 4a of the water discharge pipe 4 of the circulation pump 6 is opened into the support floor 11, and the suction port 3a of the water suction pipe 3 of the circulation pump 6 is opened upward into the drainage chamber 25 so that the suction is performed. The front end side of the dirty water pipe 2 is inserted and opened into the mouth 3a. A suction end 7a of the treated water pipe 7 is opened upward in the drainage chamber 25.

In the above embodiment, the raw water to be treated is fed from the raw water pipe 2 as shown by the arrow 15, and when the sewage reaches the predetermined water level 5 in the treatment tower 1, the circulation pump 6 is started. When the circulation pump 6 is started, the sewage circulates as indicated by arrows 17, 18, 19, 20, 21 and floats the fluidized bed 12 from the position of level 13 to the position of level 14 to remove raw water and microorganisms. And the raw water is purified by biofilm treatment.

The quality of the raw water in the above is BOD 40
mg / l, CODMn 350 mg / l, DOC 21
It was brown with 0 mg / l and an absorbance of 1.5 at 400 nm.

In the treatment tower, porous ceramics having a particle diameter of 1 to 2 mm and activated carbon having the same diameter were mixed in a volume ratio of 3: 7, and 30% of the volume of the treatment tower was accommodated. As the support bed, gravel (diameter 2 to 5 mm) is 5% of the volume of the processing tower.
Accommodated.

Further, the circulation pump 6 has the ability to make the linear velocity of the circulation flow in the processing tower 15 to 20 m / h.

In the above example, when the raw water was treated for 1 day, the quality of the treated water was 4 mg / l of BOD and CODM.
n 27 mg / l, DOC 16 mg / l, 400 nm
The absorbance was 0.1 or less and was almost colorless.

Therefore, if the raw water is retained for 24 hours and a small amount of the raw water is supplied, continuous purification can be achieved.

In the case of continuous purification, a small amount of raw water is continuously supplied, and the treated water exceeding the predetermined water level 5 is automatically taken out from the treated water pipe 7 as indicated by an arrow 16 to continuously treat the treated water. can do.

In the above embodiment, pressurized air was blown from the backwash diffuser 22 at the bottom of the treatment tower as indicated by arrow 23 to clean the carrier every 3 days. The amount of air supplied in this case was 10 to 20% by volume of the circulating flow. In the figure, 24 is an exhaust pipe.

[0098]

Fourth Embodiment Another embodiment of the present invention will be described with reference to FIG.

A support bed 11 is provided at the lower inside of the processing tower 1,
A fluidized bed 12 is housed above the support bed 11. The fluidized bed 12 accommodates 30% to 40% of the volume of the processing tower 1. A drainage chamber 25 with a screen 10 for preventing carrier outflow is provided above the treatment tower 1. Further, a static mixer 8 is interposed in the water discharge pipe 4 of the circulation pump 6, the tip 4a of the water discharge pipe 4 is opened into the support floor 11, and the suction port 3a of the water suction pipe 3 of the circulation pump 6 is described above. The drainage chamber 25 is opened upward, and the front end side of the dirty water pipe 2 is inserted and opened into the suction port 3a. A suction end 7a of the treated water pipe 7 is opened upward in the drainage chamber 25.

In the above embodiment, the raw water to be treated is fed from the raw water pipe 2 as shown by the arrow 15, and when the sewage reaches the predetermined water level 5 in the treatment tower 1, the circulation pump 6 is started. When the circulation pump 6 is started, the sewage circulates as indicated by arrows 17, 18, 19, 20, 21 and floats the fluidized bed 12 from the position of level 13 to the position of level 14 to remove raw water and microorganisms. And the raw water is purified by biofilm treatment.

The quality of the raw water in the above is BOD 40
mg / l, CODMn 350 mg / l, DOC 21
It was brown with 0 mg / l and an absorbance of 1.5 at 400 nm.

In the treatment tower, porous ceramics having a particle diameter of 1 to 2 mm and activated carbon having the same diameter were mixed in a volume ratio of 3: 7, and 30% of the volume of the treatment tower was accommodated. As the support bed, gravel (diameter 1 to 3 mm) is 5% of the volume of the processing tower.
Accommodated.

Further, the circulation pump 6 has the ability to make the linear velocity of the circulating flow in the processing tower 15 to 20 m / h.

In the above example, when the raw water was treated for 20 hours, the quality of the treated water was BOD 4 mg / l, C
ODMn 27 mg / l, DOC 16 mg / l, 40
The absorbance at 0 nm was 0.1 or less, and it was almost colorless.

In the above-mentioned embodiment, air (gas-liquid flow rate ratio (vg / vl) was 0.05) was supplied to the circulation pump 6 through the air supply pipe 9 as shown by the arrow 26, and
The air and the raw water are agitated and mixed by the static mixer 8, so that the contact between the air and the microorganisms is further improved and the treatment efficiency is improved, so that the daily treatment amount in the treatment tower of the same volume is improved. I was able to.

In the above-mentioned embodiment, the carrier in the treatment tower flows with water and the upward flow of water, so that it is not necessary to provide a special driving means for the carrier flow, and the specific gravity of the carrier is somewhat heavy. However, there is no hindrance to the flow.

In the above-mentioned embodiment, since the porous ceramics and the carbon content are mixed almost uniformly at a predetermined ratio, it is possible to give the far-infrared weak current and some other effects to the microorganisms of the carrier. It is presumed that it has the effects of suppressing the growth of microorganisms, maintaining the activity of biofilms, and maintaining a certain thickness to prevent the generation of sludge.

[0108]

EFFECT OF THE INVENTION According to the present invention, since the operation with significantly less surplus sludge is possible in the biofilm treatment, clogging is less likely to occur, and stable treatment performance can be maintained over a long period of time. It also has the effect of making maintenance easier.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of an embodiment of a fluidized bed in which a means for supplying fine bubbles of the present invention is not installed.

FIG. 2 is a conceptual diagram of an example of a fluidized bed that is also installed.

[Explanation of symbols]

1 processing tower 2 Sewage pipe 3 Water absorption pipe 5 water level 6 circulation pumps 7 treated water pipe 8 static mixer 9 Air supply pipe 10 screens 11 Support floor 12 fluidized bed 25 Drainage chamber

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Claims (10)

[Claims] 1. A granular material of porous ceramics having SiO ₂ and Al ₂ O ₃ as main components and a mixture of granular carbon content are used as a carrier for microorganisms, and the carrier is purified in a fluidized state. A method for purifying water, characterized in that the water to be treated is brought into contact with the microorganisms of the carrier. 2. A volume ratio of 10% by volume as the porous ceramics.
The water purification method according to claim 1, wherein 80% by volume and 20% by volume to 90% by volume as the carbon content are used. 3. The method for purifying water according to claim 1, wherein the carrier is caused to flow while supplying fine bubbles of a gas containing oxygen. 4. The method for purifying water according to claim 3, wherein the gas containing oxygen is air or a gas containing oxygen at a concentration higher than air, and the carrier is caused to flow under the supply of fine bubbles. . 5. The porous ceramic carrier is formed by adding a pore-forming material to two or more kinds selected from clay, silica stone, or aluminum hydroxide and firing the mixture. The method for purifying water according to any one of 2, 3, or 4. 6. A fluidized bed treatment tower in which a granular material of porous ceramics containing SiO ₂ and Al ₂ O ₃ as main components and a mixture of granular carbon components are packed as a carrier are purified. A water purifying device, which is provided with a water supply means for flowing the power water in an upward flow. 7. The volume percentage of porous ceramics is from 10% by volume.
The water purifying apparatus according to claim 6, wherein 80% by volume and 20% by volume to 90% by volume as the carbon content are used. 8. The water purifying apparatus according to claim 6, further comprising a supply means for supplying fine bubbles of a gas containing oxygen. 9. The gas containing oxygen is air and a gas containing oxygen at a concentration higher than that of air.
The water purification device described. 10. The porous ceramic carrier is clay,
7. The water purifying apparatus according to claim 6, wherein the pore-forming material is added to two or more kinds selected from silica stone or aluminum hydroxide and fired and molded.