JP3242363B2 - Microbial carrier and method for purifying sewage using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microorganism carrier and a method for purifying sewage using the same. More particularly, the present invention relates to a microorganism carrier capable of improving not only the amount of sludge generated but also the efficiency of sewage treatment. It relates to a method for purifying sewage using the same.

[0002]

2. Description of the Related Art Hitherto, biological treatment has been known to be effective as an organic wastewater treatment, and in particular, activated sludge method is widely used as the most universal method. However, this activated sludge method has a disadvantage that, although the sedimentation of solids in the sedimentation layer is improved, the amount of sludge generated increases due to the growth of filamentous fungi and the associated sludge treatment cost is high. Was.

Further, in the case of this method, the treatment efficiency is often remarkably reduced due to the impact load phenomenon due to the amount of wastewater, load fluctuation and inflow of toxic substances. To solve these problems, sewage treatment methods such as the sprinkling filter method and the rotating disk contact method have been tried in the past.However, in any of these methods, microorganisms are desorbed or in winter. In addition to the disadvantage of freezing, there is a drawback that odor is generated.

[0004] Such a disadvantage is that a helical microorganism single body in which a cored or hollow core rod-shaped body composed of a large number of projecting loop-like filaments on the outer surface is spirally formed (Japanese Patent Application Laid-Open No. 62-3784, 1987). 62-38294). Therefore, the present inventors have further studied this single spiral microorganism, the loop filamentous aggregate, especially when constituted by acrylic fiber, while improving the efficiency of biological treatment of organic wastewater, The present inventors have found out that it is difficult to maintain the loop shape due to the weakness of the acrylic fiber alone and arrived at the present invention.

[0005]

Accordingly, a first object of the present invention is not only to reduce the amount of sludge generated, but also to increase the amount of microorganisms attached, thereby making the biological treatment of organic wastewater more efficient than ever. It is an object of the present invention to provide a microorganism carrier which can be carried out by a microorganism carrier. A second object of the present invention is to not only prevent the phenomenon that microorganisms are detached or freeze in winter, but also reduce the amount of sludge generated by performing processes from anaerobic to aerobic. It is another object of the present invention to provide a method for purifying sewage that can also suppress generation of offensive odor.

[0006]

SUMMARY OF THE INVENTION The above objects of the present invention are attained by providing a microbial carrier characterized by comprising polyvinylidene chloride fibers and acrylic fibers planted so as to form a large number of U-shaped loops on a backbone. Achieved by

[0007] The microorganism carrier of the present invention is formed by fixing a large number of U-shaped fibers having a function of carrying microorganisms to the backbone thereof, as described in Japanese Patent Application Laid-Open No. Sho 62-3784.
No. In the present invention, in particular, poly- wefts are planted on the backbone and form U-shaped loops.
Use a combination of vinylidene chloride fiber and acrylic fiber.

As a result, the ability to carry microorganisms is increased as compared with the case where one type of fiber is used, and the ability to treat sewage is enhanced. Although the reason that the combination with the acrylic fiber is particularly effective for purifying wastewater is not clear, it is presumed that one reason is that the acrylic fiber has appropriate hydrophilicity.

A microorganism carrier (hereinafter abbreviated as BM) using only vinylidene chloride fiber as the weft, and a microorganism using both the polyvinylidene chloride fiber and the acrylic fiber in the weft so that the volume ratio becomes 1/1. Comparing with a carrier (hereinafter abbreviated as SM), SM has a larger specific surface area than BM, and has more irregularities on the surface of the carrier. That is, for microorganisms, SM can be said to have more favorable conditions for adhering to the medium surface, and in fact, the actual adhering amount of volatile organic substances is also as shown in the examples described later.
Surprisingly, the case of SM was 3 more than that of BM.
There are many about 0 to 64%.

[0010] The fiber diameter of the weft is preferably small from the viewpoint of increasing the specific surface area of the microorganism carrier.
From the viewpoint of manufacturing technology or preventing yarn breakage during actual use, the fiber diameter itself has its own limit. For example, in the case of polyvinylidene chloride fiber, 30 to 100 μm, and in the case of acrylic and nylon fiber, 1 to 100 μm,
In particular, the thickness is preferably in the range of 5 to 50 μm. The material and fiber diameter of the warp constituting the backbone together with the weft are not particularly limited.

In treating sewage using the microorganism carrier of the present invention, it is preferable to first remove inorganic SS and solids from the collected sewage, and then, by aeration, the sewage proceeds from upstream to downstream. It is preferable to adjust the amount of dissolved oxygen to increase. By doing so, not only the BOD can be reduced but also the nitrogen content can be effectively removed.

Therefore, the sewage treatment apparatus comprises at least a water collecting tank for collecting sewage, a filtration tank for precipitating and filtering inorganic SS and solids, and an aeration tank for introducing dissolved air to adjust dissolved oxygen. You. Then, for example, the aeration tank is divided into four sections, the dissolved oxygen in each of the first to fourth sections is sequentially adjusted to 1, 2, 3, 4 ppm from the upstream side, and the residence time in each tank is set to about 12 hours in total. Process continuously. By doing in this way, sufficient processing from anaerobic processing to aerobic processing can be performed.

The provision of a filtration tank before the aeration tank is
It is important to prevent the attachment of inorganic substances that are heavy and easily fall, and to keep the adhesion state of microorganisms good. PH, BOD, COD (Mn), COD (C
It is preferable to employ r), SS, phosphorus concentration, nitrogen concentration, surfactant concentration and the like. The analysis of these measurement items can be appropriately performed by a known method.

[0014]

The microorganism carrier of the present invention comprises acrylic fiber and
Since two types of polyvinylidene chloride fibers are planted on the backbone to form a number of U-shaped loops,
The adhesion state of the microorganisms is extremely good, and the sewage treatment capacity of the microorganisms can be maximized, whereby the biological treatment of the organic wastewater can be efficiently performed.

Further, unlike the general activated sludge method, the method for purifying sewage of the present invention does not require a secondary sedimentation tank, a dewatering facility, a sludge return facility and other auxiliary facilities, but is anaerobic. Since the entire process from the treatment to the aerobic treatment can be performed, the amount of generated sludge can be reduced as compared with the conventional case, and the generation of offensive odor can be suppressed.

[0016]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

Embodiment 1 FIG. 1 shows an example of the microorganism carrier of the present invention in which two types of weft yarns of fiber a and fiber b are planted so as to form a large number of U-shaped loops on the backbone.
FIG. 2 is a schematic view showing an example of an apparatus in a case where the microorganism carrier 1 of FIG. 1 is filled in an aeration tank 2 to perform sewage treatment.

In FIG. 2, reference numeral 2 denotes an aeration tank composed of four compartments, each having two reaction tanks 5 filled with the microorganism carrier 1, reference numeral 3 denotes a water collecting tank, reference numeral 4 denotes a filtration tank, and reference numeral 6 denotes an air blower. is there. The microbial carrier 1 is filled so that the distance between the microbial carrier 1 and the wall of the reaction tank 5 is at least 10 mm in order to facilitate the rotation of water. And the amount of oxygen dissolved in each reaction tank was adjusted by providing valves 7 respectively.

The sewage filtered in the filter tank 4 flows into the first reaction tank 5 through the pipe 8 and is purified while passing through the reaction tank. In addition, the reaction tank 5 should be spaced at least 20 mm from each other,
The water temperature in all the reaction vessels was maintained at 20 ± 1 ° C.

Further, the dissolved oxygen in the aeration tank 2 was measured as needed using a DO-meter, and the amount was kept constant, and the hydrogen ion concentration was measured as needed using a pH-meter. The dissolved oxygen amount in each reaction vessel was 1 ppm, 2 ppm, 3 ppm and 4 pp from the upstream side to the downstream side in order.
m.

32.4 liters of SM as microbial carrier
After performing continuous treatment of sewage for 80 days using, the filled microorganism carrier is extracted from the aeration tank so that the attached microorganisms (sludge) do not fall off, and the sludge attached to the carrier is removed from a fixed amount of distilled water. Then, it was put in a dry oven and completely dried at 103 ° C. for 3 to 4 days, and the dried product was weighed.

Next, the dried product was completely baked at 600-650 ° C., the remaining weight was measured, and the amount of microorganisms adhering to the microorganism carrier was determined from the difference between the two. The results are as follows: 22.5 g, 24 g, 2 g
The weight was 3.8 g and 17.5 g, and the amount of adhesion was the largest in the second chamber. When the BOD and nitrogen concentrations in water before and after the treatment were measured, the BOD reduction was 90%, the nitrogen removal rate was 74% by the indole method, and 61% by the hexane extraction method.
%Met.

On the other hand, when 40 liters of BM was used as a microorganism carrier, sewage treatment was performed under exactly the same conditions, and the respective values were measured in the same manner. , 13.8 g, 18.5 g,
16 g and 12.5 g, which are less than in the case of the present invention,
The BOD reduction was 86%, and the nitrogen removal rate was 64% by the indole method and 52% by the hexane extraction method. These results demonstrate the effectiveness of the microbial carrier of the present invention and that the method for purifying sewage of the present invention sufficiently performs from anaerobic treatment to aerobic treatment.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a microorganism carrier of the present invention in which two types of fibers are planted so as to form a large number of U-shaped loops on a backbone.

FIG. 2 is a schematic view showing one example of an apparatus for performing the sewage treatment of the present invention.

[Explanation of symbols]

 1 Microbial carrier 2 Aeration tank 3 Water collecting tank 4 Filtration tank 5 Reaction tank 6 Air blower 7 Valve

Continuation of the front page (51) Int.Cl. ⁷ identification code FI C12M 1/40 C12M 1/40 Z (58) Field surveyed (Int.Cl. ⁷ , DB name) C12N 11/08 C02F 3/00-3 / 10 C12M 1/40

Claims (2)

(57) [Claims] 1. A microbial carrier comprising polyvinylidene chloride fibers and acrylic fibers planted so as to form a large number of U-shaped loops on a backbone. 2. The fiber diameter of a fiber forming a U-shaped loop is
The microorganism carrier according to claim 1, which has a thickness of 1 to 100 μm.
body.