JPH11128966A - Apparatus for treating high concentration waste water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus in which BOD and SS can be remarkably decreased, in an apparatus for treating high concn. waste water. SOLUTION: A filter medium layer is formed by charging a filter medium 2 comprising a synthetic resin fibrous material in a treating tank 1, and an air pipe for aerating the filter medium and an air pipe for agitating the filter medium are provided below the filter medium layer, and a feeding pipe for a raw water and a removing pipe for treated water are respectively provided at the bottom part and the top part of the treating tank 1, and in addition, the removing pipe for the treated water and the feeding pipe for the raw water are connected with each other through an on-off valve. As the fibrous filter medium 2 is used, it is easily cleaned while contact area with waste water is large and efficient treatment can be done and it is possible to form a consolidated precise filter medium layer by circulating the treated water.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an apparatus for treating organic sewage such as sewage.

[0002]

2. Description of the Related Art Conventionally, apparatuses for treating organic wastewater are known. Processing apparatuses using a filter medium having a specific gravity of 1.0 or more, such as anthracite or ceramic, are well known. In addition, there are a large number of processing apparatuses using a buoyant filter medium having a specific gravity close to 1, and the shape and dimensions of the filter medium used in these apparatuses are 5 to 25 mm in a rectangular parallelepiped 10 to 30 mm square.
Are known. These filter media dimensions are larger than filter media such as anthracite and ceramic. This is considered to prevent clogging of the filter layer.However, if the filter medium size is too large, the filtration resistance is not uniform, and a large amount of water to be treated flows to a low resistance portion, so-called a drift phenomenon occurs, and the treatment is difficult. This results in trouble. Furthermore, there are many filter media called fiber filter media in which synthetic fibers are bundled or formed into a cocoon shape. Many of these are made of one type of fiber, which may cause an increase in filtration resistance or deformation due to being strongly pressed by gravity during drainage. Also,
In the upward flow filtration, raw water and air flow in the same direction,
There is a disadvantage that S easily leaks into the treated water.

[0003]

However, in a high-load processing apparatus using a buoyant filter medium having a specific gravity close to 1, the filtering speed is low, so that the pressure density of the filter medium is not sufficient, and air rising in the layer is not sufficient. At the same time, SS may escape into the treated water. In the case of anthracite or ceramic filter media with a large specific gravity, or foamable filter media with an extremely small specific gravity,
Porosity is small, clogging by SS occurs in a short time, cleaning frequency increases, and large power is required for cleaning.
Furthermore, a large-sized filter medium causes a drift phenomenon, which hinders processing.

[0004]

SUMMARY OF THE INVENTION The present invention provides fine filter media by adjusting the ratio of filter media layer height to water layer height and circulating a part of filtered water. A filter medium layer is formed that is hardly clogged and easily backwashed while catching up. That is, a first filament having a fineness of 18 to 65 denier which is a heat-fusible conjugate fiber having a core of polypropylene and a sheath of polyethylene as a filter medium, and a second filament having a polypropylene fiber and a fineness of 3 to 10 denier. A web formed by blending a filament and a third filament having a fineness of 1.5 to 6 denier with a heat-fusible conjugate fiber having a core of polypropylene and a sheath of polyethylene is needle-punched into a cloth, and the web on both sides is formed. A heat treatment is performed without smoothing the raised state, and the weight of the web is 200 to 80.
A cloth-shaped plate having a thickness of 0 to 8 g / m 2 and a thickness of 2 to 8 mm was produced, and the cloth-shaped plate was cut into 3 to 5 mm squares and used as a filter medium. In addition, by setting the ratio of the height of the filter medium layer to the height of the water layer to 65:35 to 50:50, the filter medium can be easily washed. This was solved by increasing the pressure density by circulating the treated water.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The above-mentioned cloth-shaped plate-shaped filter medium is a non-woven fabric, so that it has a high porosity and is excellent in adhering microorganisms. Therefore, the amount of microorganisms in the filter layer can be kept large. In addition, three types of filaments having different thicknesses are used in order to prevent crushing due to gravity at the time of filtration pressure or drainage. The cloth-shaped plate-shaped filter medium is densely packed but has a high porosity, so that pressure loss due to clogging is small and filtration time is long. In the washing, by setting the ratio of the filter medium layer height to the water layer height to 65:35 to 50:50, it is easy to flow by diffused air from below, and the trapped SS and excess sludge can be separated. At this time, the amount of air is smaller than that of a device using anthracite or ceramic filter media. Also,
The leakage of SS, which is a drawback of the upward flow type, is solved by circulating the treated water, and the treated water having a lower SS than before can be obtained. Furthermore, since the circulating process mixes the treated water in which oxygen is sufficiently dissolved into the raw water, the amount of aerated air may be smaller than that of the conventional device. Hereinafter, a sewage treatment apparatus using a filter medium according to the present invention will be described with reference to the drawings.

[0006]

1 and 2 show a processing apparatus according to the present invention. In FIG. 1, reference numeral 1 denotes a processing tank having a lower portion formed in an inverted conical shape and a settling portion 1a provided, and 2 denotes a processing tank. Reference numeral 1 denotes a filter medium, reference numeral 3 denotes an air nozzle for aeration provided at a lower part in the filter medium layer, and reference numeral 4 denotes an air nozzle for agitating the filter provided at a lower part of the draft tube 5. Next, reference numeral 6 denotes a raw water supply pipe, reference numeral 7 denotes a treatment water overflow trough, reference numeral 8 denotes a treatment water extraction pipe, reference numeral 9 denotes a circulating water extraction pipe, reference numeral 10 denotes a sediment withdrawal pipe, and reference numeral 11 denotes aeration. 12 is a blower for washing, 12 is a blower for washing,
Reference numeral 3 denotes a circulation pump, and reference numeral 14 denotes a mesh for holding a filter medium.

The apparatus according to the present invention is configured as described above. Raw water is mixed with circulating water that is a part of the treated water and supplied to the treatment tank 1. At the same time, fine contaminants are trapped and removed in the filter medium layer, and at the same time, the organic pollutants are decomposed by contacting microorganisms inhabiting the filter medium 2, and the overflow trough passes through the upper part of the treatment tank 1. 7. Further, the treated water can be taken out as clarified water through a take-out pipe 8. At the same time, a part of the treated water is mixed with the raw water through the circulating water take-out pipe 9 and the circulating pump 13, and is again supplied to the treatment tank 1 through the mixed liquid supply pipe 6a.

On the other hand, by simultaneously operating the aeration blower 11 and diffusing air from the aeration air nozzle 3, the microorganisms retained on the surface and inside of the filter medium 2 can be activated. The organic pollutants in the supplied raw water can be continuously decomposed. Next, when the filter medium layer is clogged with sludge generated at the time of decomposition of impurities and organic substances by such an operation, supply of raw water and circulation of the treated water are stopped, and a treated water take-off valve is provided. 8a is closed, the sediment at the bottom of the treatment tank 1 is pulled out from the drawing pipe 10, and then the cleaning blower 12 is operated to supply air from the air nozzle 4 for stirring the filter medium and to remove the filter medium 5 to 5 through the draft tube 5. Stir for 10 minutes. Thereafter, the washing water is supplied from the washing water pipe 15 through the circulation pump 13 to the mixed liquid supply pipe 6 while the air supply from the filter medium stirring air nozzle 4 is continued.
Supply from a. Drainage containing impurities and excess sludge separated from the filter medium 2 is discharged from the drainage pipe to the outside of the tank through the upper part of the treatment tank 1, the overflow trough 7, and the treated water discharge pipe 8 for 5 to 15 minutes. This time varies depending on the raw water condition and the filtration time. After the completion of the washing, the washing blower 12 is stopped, the circulation valve 9a is opened, and the washing water valve 15a is closed to stop the supply of the washing water, and only the circulation is performed for about 5 minutes.
Thereafter, the supply of raw water and the operation of the aeration blower 11 are started to perform filtration, the treated water is discharged for 10 to 20 minutes, and then the treated water take-out valve 8a is opened, and the treated water take-out pipe 8 is opened.
And remove it as clear water.

FIG. 2 shows a processing apparatus without a draft tube 5 as compared with the processing apparatus shown in FIG. 1, and the filter medium is washed by a filter medium stirring air nozzle 4 installed at a part below the filter medium layer. The other components are the same as those in FIG.

Tables 1 and 2 show the relationship between the processing performance of the apparatus and the BOD and the aeration air amount when test processing is performed using the processing apparatus according to the present invention as described above. As shown in Table 1, treated water B compared to raw water
OD and SS are greatly reduced, and as shown in Table 2, the amount of aerated air used is also significantly reduced.

[0011]

[Table 1]

[0012]

[Table 2]

[0013]

As described above, according to the present invention, in a wastewater treatment apparatus using a filter medium made of synthetic resin fiber material,
The treated water section and raw water inflow section are connected via a pump to circulate a portion of the treated water, and the ratio between the height of the filter medium layer and the height of the water layer is charged so as to be appropriate for stirring. SS and organic pollutants can be separated and removed in a single tank. In particular, the formation of the filter layer is stabilized by circulation, the dissolved oxygen in the treated water can be reused, and the advanced treatment of the sewage becomes possible. In addition to savings, the filter media can be completely washed.

[Brief description of the drawings]

FIG. 1 is a vertical side view of a wastewater treatment apparatus according to the present invention.

FIG. 2 is a longitudinal sectional side view of another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Processing tank 2 Filter medium 3 Air nozzle for aeration 4 Air nozzle for filter medium stirring

Continued on the front page (51) Int.Cl. ⁶ Identification code FI B01D 29/38 580F

Claims (4)

[Claims] 1. A filter medium outflow prevention material is installed on an upper part of a cylindrical treatment tank 1 having an inverted conical settling part formed at a bottom part, and a filter medium 2 is charged below the filter medium outflow prevention material. And an air nozzle 4 for stirring the filter medium below the filter medium layer.
And a high-concentration sewage treatment apparatus further comprising a raw water supply pipe below the treatment tank 1, an outlet for treated water above the treatment tank, and a sediment outlet at the bottom bottom of the treatment tank. 2. A first filament having a denier of 18 to 65 denier, a heat-fusible conjugate fiber having a core of polypropylene and a sheath of polyethylene, and a polypropylene fiber as a material of the filter medium 2 to be charged into the treatment tank. A web obtained by mixing a second filament having a fineness of 3 to 10 denier and a third filament having a fineness of 1.5 to 6 denier in a heat-fusible composite fiber whose material is polypropylene as a core and polyethylene as a sheath. Fabricate by needle punching method,
A heat treatment is performed without smoothing the raised state of the web on both sides to produce a cloth-shaped plate having a weight of 200 to 800 g / m 2 and a thickness of 2 to 8 mm. The high-concentration sewage treatment apparatus according to claim 1, wherein the material cut into a 3 to 5 mm square is charged as a filter medium. 3. The cloth-shaped plate-shaped filter medium is charged so that the ratio of the filter medium layer height to the water layer height of the filter medium 2 charged in the treatment tank 1 is 65:35 to 50:50. The high-concentration sewage treatment apparatus according to claim 1 or 2, characterized in that: 4. A treatment water section of the treatment tank 1 and a raw water inflow section are connected via a pump, and a part of the treatment water is supplied at a linear velocity of 5 to 2
The high-concentration sewage treatment apparatus according to claim 1, wherein circulation is performed at 0 m / h.