JPS61271089A - Filter for waste water using immobilized microorganism - Google Patents

Abstract

PURPOSE:To remove not only turbid matters but also substance relating to BOD, COD, and humic acid, etc. simultaneously and to prevent generation of excess sludge by using immobilized microorganism obtd. by immobilizing microorganism, activated sludge, soil, etc. on a high molecular material by an entrapping immobilization method, as filter medium. CONSTITUTION:In a filter 1 for capturing turbid matters in the feed water through a filtration bed packed with a filter medium, microorganism prepd. by pure culture or mixed culture, activated sludge, soil, etc. are immobilized on a high molecular substance such as polyurethane, etc. by entrapping immobilization. Obtd. immobilized microorganism 10-12 is packed as filter medium. By this method, removal of substances relating to BOD, SS including removal of hardly decomposable humic acid are possible simultaneously gene rating thereby almost no excess sludge.

Description

[Detailed Description of the Invention] Main business: Summer and North! The present invention is characterized in that it is filled with R material. The present invention relates to a filtration device that captures suspended matter in raw water using a layer, and particularly relates to a filtration device that simultaneously removes not only suspended matter but also BOD components, COD components, fumic acid, fulvic acid, etc. in wastewater.

BACKGROUND OF THE INVENTION Conventionally, an activated sludge method has been used to remove suspended solids, BOD components, COD components, etc. contained in wastewater. In this method, BOD and COD components are brought into contact with activated sludge in an aeration tank and are biologically decomposed, suspended components are adsorbed by activated sludge, and activated sludge and treated water are separated in a solid-liquid separator. be done. As a solid-liquid separator, a flotation separator and a sedimentation separator are generally used. The cross-sectional area of these devices is determined by the ratio of ascent and sink rates to throughput. Although flocculants or flocculant aids have been used to increase the floating speed and sinking speed, they have not achieved dramatic effects.

The cross-sectional area of these aeration tanks and solid-liquid separation devices is larger than that of other water treatment devices, and their biggest drawback is that they require a larger site area.

On the other hand, as a solid-liquid separator, a transit device filled with granular material such as sand or anthracite is used.

(Note: However, a temporary device filled with granular R material can remove suspended solids, but cannot remove BOD and COD components.

It is also possible to use sand, anthracite, or the like on the surface of which microorganisms are attached as the granular material, but the attached microorganisms are likely to peel off, and the separated microorganisms are likely to mix into the treated water. In addition, the attached microorganisms multiply and a large amount of surplus sludge is generated.

Therefore, the present invention aims to eliminate the drawbacks of the prior art described above, and to provide a transit device that can simultaneously remove not only suspended solids but also BOD, COD, humic acid, etc., and does not generate excess sludge. purpose.

The present invention solves the above problems by using immobilized microorganisms, in which microorganisms, activated sludge, soil, etc. are encased and immobilized in a polymeric material, as a door material.

That is, the transit device according to the present invention is characterized in that it contains immobilized microorganisms obtained by entrapping and immobilizing pure cultured or mixed cultured microorganisms, activated sludge, soil, etc. in a polymeric substance as a filter medium.

The microorganisms to be immobilized in the present invention may be pure cultures or mixed cultures of any microorganisms such as bacteria, actinomycetes, molds, and yeasts, or activated sludge. Furthermore, for the treatment of water containing a large amount of humic acid or fulvic acid, soil that is thought to be inhabited by these degrading bacteria can be used after being immobilized.

Therefore, in the following description, the term "microorganism"
It means microorganisms in pure culture or mixed culture, microorganisms attached to activated sludge or soil.

In the present invention, it is preferable that immobilized microorganisms of different sizes are brought into contact with the wastewater in response to changes in the concentration of wastewater components in the tank. It is preferable to fill the temporary tank with immobilized microorganisms having a larger equivalent sphere diameter than those on the outflow side.

In the BOD removal process of wastewater using immobilized microorganisms, the possible causes of surplus sludge are (1) leakage of microorganisms from pellets of immobilized microorganisms, and (2) growth of floating bacteria. It is thought that most of the problems are caused by 1).

When microorganisms were immobilized as pellets, we investigated the size of the pellet and the growth state of the microorganisms, and found that when the diameter of the pellet is large, microorganisms multiply near the surface of the pellet, and are sparse in the center. The activity per unit volume of pellets is low. When pellets with large diameters are used to treat wastewater, if the concentration of organic matter in the wastewater is high, the organic matter will diffuse into the interior of the pellet, and growth will become active in the center. Conversely, when the concentration of organic matter in wastewater is low, microorganisms proliferate only near the surface of the pellet, and microorganisms decrease in the center due to self-digestion, thereby reducing treatment performance.

On the other hand, when pellets with a small diameter are used for BOD removal treatment of wastewater, microorganisms propagate relatively uniformly. When the concentration of organic matter in the wastewater is high, the growth of the entire pellet is active, and excess microorganisms leak out.

When the concentration of organic matter is low, the activity is high and the treatment performance is good.

Therefore, in the wastewater filtration device according to the present invention, the concentration of organic matter in the wastewater is high near the wastewater inlet, the organic matter diffuses into the inside of the pellet, and the growth of microorganisms is large. It is preferable to fill it with On the other hand, near the outlet of the treated water, the concentration of organic matter in the wastewater is low, so there is less proliferation of microorganisms and less leakage of microorganisms. Therefore, pellets with a small diameter are filled on the outlet side of the treated water, so that the pellets are more effective as a T-material than in removing organic matter.

In the present invention, the spherical equivalent diameter of the immobilized microorganism is 0.5 to
It is preferable to select within the range of Ion-.

In the transit device according to the present invention, when filling immobilized microorganisms with different equivalent sphere diameters as described above, they are packed so that they do not mix with each other, or a device for separating them so that they do not mix, such as a partition net, is used. can be installed. By decreasing the specific gravity of pellets with a large diameter and increasing the specific gravity of pellets with a small diameter, they can be separated without a partition screen so that they do not mix with each other.

The polymer material used for comprehensive fixation in the present invention is
Any of polyurethane, polyacrylamide, calcium alginate, carrageenan, methoxytetraethylene glycol methacrylate, polyethylene glycol dimethacrylate, 2,2-bis[4-(methacryloxy-polyethoxy)phenyl]propane, polyethylene glycol diacrylate, polypropylene glycol diacrylate, etc. Any known immobilization material can be used.

As a material with a low specific gravity, for example, one having a specific gravity of 1.02 or less can be obtained by adding 0.5 to 20% of a urethane prepolymer to a microorganism suspension, carrying out addition polymerization, and molding.

The plate-immobilized microorganisms have a BOD removal function and act as an r-material to adsorb SS. In addition, the microorganisms grow inside the immobilized microorganisms, self-extinguish, and do not leak to the outside.
No surplus sludge is generated.

Seed of disaster■ Next, the present invention will be explained in detail based on the drawings.

FIG. 1 is a schematic cross-sectional view of a transit device showing a filter embodiment of the present invention. In this embodiment, process 1 is in chamber 2.
, the second chamber 3, the third chamber 4, the fourth chamber 5, and the fifth chamber 6. Each chamber is partitioned by a strainer 7, and the chambers 3, 4 and 5 each have a Immobilized microorganisms 10, 11 and 12 with different diameters are filled.

When filtering wastewater with this device, the wastewater must be filtered with a wastewater population of 8
It is aerated with air sent from the air pipe 9 in the first chamber 2, and then flows into the second chamber 3, third chamber 4, and fourth chamber 5 filled with T-material made of immobilized microorganisms. While flowing down, suspended solids are removed, as well as BOD, COD, etc. The treated water flows out from the treated water outlet 13. After water has been passed for a certain period of time, backwash water is allowed to flow in from the backwash pipe 14 and discharged from the drain 15 in order to remove accumulated turbidity.

In the embodiment shown in FIG. 2, two types of immobilized microorganisms 16 and 17 having different specific gravities are filled in the process 1. In this case, after backwashing, the immobilized microorganisms 16 and 17 are separated and deposited without being mixed, depending on their specific gravity.

FIG. 3 shows an embodiment in which an aeration tank 18 is provided separately and aeration is carried out there.

FIG. 4 shows an embodiment in which the transient is carried out in an upward flow.

In addition, in the transit apparatus shown in FIGS. 2, 3, and 4, it is preferable to provide a wire gauze at the top of the tower to prevent pellets from overflowing.

Furthermore, when filtering wastewater in which it is difficult to separate SS and pellets, it is recommended to mix solid agents with high specific gravity such as sand, anthracite, activated carbon, garnet, etc. during pellet production to adjust the specific gravity of the pellets. preferable. For example, diameter 1
It is preferable that the specific gravity be 1.5 to 2.0 for small pellets around the dragon, and 0.5 to 1.5 for pellets with a diameter of 1.5n+ or more.

Example 1 Activated sludge from a sewage treatment plant was concentrated to an MLS of 340,000 μ/1 on a P2 construction site. A solution containing 36% acrylamide and 2% triacryl formal was prepared, and an equal amount of the above activated sludge concentrate was suspended in this solution. To this suspension, 0.5% of 3-dimethylaminopropionitrile and 0.25% of potassium belloxonisulfate were added and polymerized to form three types of spherical pellets with diameters of 41-13 and 2U. Molded.

In the transit device shown in FIG. 1, which has a filter tank with a diameter of 100 + n and a content of 51, pellets with a diameter of 4 fins are placed in the second chamber 3, pellets with a diameter of 3 n+ are placed in the third chamber 4, The fourth chamber 5 was filled with pellets each having a diameter of 211 at a filling rate of 10%.

When food wastewater with a BOD of 54-65 .mu./f and 1ss of 23-35 .mu.l was treated for 20 days with a residence time of 15 minutes, treated water with a BOD of 8-12 .mu./f and a concentration of less than 553 mg/Il was obtained.

Example 2 Activated sludge from a sewage treatment plant was concentrated to an MLS of 340,000 μ/l. A solution containing 36% polyethylene glycol #600 diacrylate and 2% triacrylic formal was prepared, and an equal amount of the above activated sludge concentrate was suspended in this solution. To this suspension, 3-dimethylaminopropionitrile was added to 0.5% and potassium belloxonisulfate was added to 0.25%, and polymerized.
The pellets were molded into four types of spherical pellets: S and 1 Tsuru.

Using the same apparatus as in Example 1, pellets with a diameter of 4 mm were placed in the first chamber 2, pellets with a diameter of 311 I in the second chamber 3, pellets with a diameter of 2 nm in the third chamber 4, and pellets with a diameter of 2 mm in the fourth chamber 5. 1 fl of pellets were each filled to a filling factor of 10%.

Machine factory wastewater with a BOD of 76-140cm/1.5S30-45cm/1 was continuously treated for 25 days using the above-mentioned equipment at a residence time of 3'0 minutes with aeration in the first room.
Treated water with a BOD of 8 to 15 .mu./2 and an SS of 3 .mu./l or less was obtained.

Example 3 A urethane polymer with a main chain of polyethylene glycol and polypropylene glycol, a molecular weight of 4,000 to 5,000, and isocyanate groups at both ends was added to activated sludge MLS 320,000/1 at a sewage treatment plant in an amount of 5%. The mixture was polymerized and formed into pellets with a diameter of 1.5 mm. The specific gravity of this pellet was 1.03 or less.

Separately, pellets with a diameter of 1 wI used in Example 2 were prepared. The specific gravity of this pellet was 1.04 to 1.06.

Using the transient device shown in Fig. 2, which has a filtration tank with a diameter of IQO mm and a content of 5e through the fresh water, pellets with a diameter of 1 l and pellets with a diameter of 1.5 liters were mixed at 15% each. It was filled to a total filling rate of 30%.

When food wastewater with a BOD of 25-42 .mu./1.5S 15-34 .beta. was treated with the above-mentioned apparatus at a residence time of 20 minutes for 20 days, treated water with a BOD of 8-12 .mu./1ss 3.mu./2 or less was obtained.

Even after backwashing, there is a diameter of 1 at the bottom of the r process due to the difference in specific gravity.
1.5 fl pellets are deposited on top.

Example 4 Soil log of the surface layer of farmland in Kamihongo, Matsudo City, Chiba Prefecture was 40 m
After suspending the suspension in tap water and homogenizing it, 3% of urethane prepolymer was added, polymerized, and formed into a pellet with a diameter of 1.5 fins.

After the experiment of Example 3 was completed, the entire amount of the above soil-containing pellets was filled. After backwashing, a 1-diameter pellet of polyethylene glycol #600 diacrylate was placed in the lower part, a 1.5-diameter pellet of urethane containing soil was placed in the center, and a 1.5-diameter pellet of urethane containing activated sludge was placed in the center.
m pellets accumulate at the top. The upper urethane pellet was fluidized by aeration.

When 5 μ/l of humic acid was added to the wastewater used in Example 3 and treated with the above device for a residence time of 60 minutes, the BOD was 8~
12mg/j', 553mg/f or less, humic acid 2-3
mg/l of treated water was obtained, and it was found that humic acid could also be treated.

In each of the above examples, when the sludge conversion rate, which is the amount of sludge generated from BOD removal, is calculated from the amount of SS discharged by backwashing, it is 2 to 4%, and almost no surplus sludge is generated. It turned out that. This is thought to be because microorganisms multiply inside the pellet and do not leak to the outside, and it is thought that self-digestion occurs inside the pellet.

Furthermore, when various wastewaters were treated using anthracite as a filter medium as a conventional method, BOD components, humic acid, etc. could hardly be removed.

As described above in No. 311 and Jiuguo, according to the present invention, SS can be removed simultaneously with BOD removal, including the removal of persistent humic acid, and in this case, almost no surplus sludge is generated.

In addition, in the conventional method of using anthracite etc. as a filter medium, surface layer filtration tends to occur, but in the present invention, if the wastewater inlet side is filled with immobilized microorganisms with a large equivalent spherical diameter, r.
The entire material layer is effectively utilized.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of a passing device showing an embodiment of the present invention, FIG. 2 is a schematic sectional view of a passing device showing another embodiment of the present invention, and FIG. 3 is a schematic sectional view of a passing device showing another embodiment of the present invention. FIG. 4 is a schematic cross-sectional view of a transit device showing still another embodiment of the present invention. . Engineering...-Process, 7...Strainer, 8...Wastewater inlet, 13...Treated water outlet, 10.11.12.
16.17.19 and 20...immobilized microorganisms, 18.
・・Aeration tank

Claims (4)

[Claims] (1) In a filtration device that traps suspended matter in raw water with a single layer filled with filter media, the filter media is filled with immobilized microorganisms that are made by entrapping and immobilizing pure cultured or mixed cultured microorganisms, activated sludge, soil, etc. in a polymeric substance. A wastewater filtration device using immobilized microorganisms. (2) The wastewater filtration device according to claim 1, wherein the inlet side of the wastewater is filled with immobilized microorganisms having a larger equivalent spherical diameter than the outlet side of the treated water. (3) The wastewater filtration device according to claim 2, comprising a device for filling pellets with different equivalent sphere diameters in a filtration tank so that they do not mix or separating them so that they do not mix. (4) The wastewater filtration device according to claim 2 or 3, wherein the inlet side of the wastewater is filled with immobilized microorganisms that are encircled and immobilized with urethane resin as a filter medium.