JPH05123692A - Drainage disposal equipment of upward flow sludge blanket type - Google Patents

Abstract

PURPOSE:To constitute a liquid-gas separation mechanism of a simple structure in comparison with a conventional method so that outflow of a solid component is diminished in the treated water side as a disposal equipment in an upward flow type sludge blanket method for treating organic drainage by anaerobic microorganisms. CONSTITUTION:A screen 4 of a filament bundle is formed by parallel arranging the filament bundle in a state wherein it is overlapped in the thickness direction so that passage of a solid component is inhibited underwater and passage of gas is freely permitted in gas. This screen 4 is stretched in the upper part of a treatment tank 1 so that one part of water surface in the inside of the treatment tank is surrounded in a range over the water surface from below the water surface. A pulling means of treated water is provided in the water area surrounded by this screen 4. Thereby the solid components are filtered by the screen 4 add then treated water is pulled out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for treating organic wastewater, and more particularly to a device for decomposing and treating organic matter in wastewater by utilizing anaerobic microorganisms.

[0002]

2. Description of the Related Art Conventionally, there has been proposed a method for decomposing and treating organic matter contained in wastewater containing organic matter, that is, so-called organic wastewater, which has been proposed. As one of such methods, for example, a treatment method using anaerobic microorganisms is known, in which wastewater (untreated water) is passed through a treatment tank filled with anaerobic microorganisms to biologically decompose organic substances in the wastewater.

Regarding the method of treatment with anaerobic microorganisms, in recent years, by flowing wastewater (untreated water) in a treatment tank in an upward flow, aggregates (pellets) of anaerobic microorganisms called granules are formed. Upflow sludge blanket method (UASB) to flow (float) granules
Method: Sometimes called anaerobic sludge blanket method) is proposed.

By the way, when the above-mentioned methods, apparatuses, etc., which have been proposed or applied to actual processing systems (methods, apparatuses), are examined, these processing systems (methods, apparatuses) up to now have not yet been examined. It was recognized that there were various problems to be improved.

The above problems are listed below in a list.

(1) In the UASB method, when the amount of drainage flowing into the treatment tank varies, unless the upward flow velocity is properly controlled, sludge (pellets) floating with the generated gas may flow out to the treated water side. There is

(2) In the UASB method, since the density of sludge formed depends on the quality of untreated water, appropriate control of the flow velocity is important also from this point.

(3) Since it is a transient treatment system, if the sludge is not fluidized properly, the contact efficiency between untreated water and sludge deteriorates and the treatment efficiency deteriorates.

(4) In the conventional UASB method device,
Although the solid / liquid separation mechanism has a relatively complicated structure as shown by reference numerals 30 and 31 in FIGS. 6 (a) and 6 (b), the gas / solid / liquid separation efficiency is not always required. If it is not satisfied and the problems (1) to (3) described above are present, it is difficult to prevent the solid component from flowing out.

If minute sludge may flow out of the tank due to the above problems, it is difficult to maintain an appropriate amount of granules having a relatively slow growth in the tank.

Therefore, in order to avoid such a problem,
For the purpose of separating bubbles from solids, recently, there has been proposed a device in which a filter layer using a floatable filter medium is provided to surely separate gas and solids. A mechanism for this is shown, for example, in FIGS. 6 (c) and 6 (d).
An example is a type in which a screen is filled between a pair of upper and lower screens 33, 34. However, with such a configuration,
Since it is necessary to make the aperture of the screen smaller than the diameter of the floatable filter medium, a new problem of blockage of the screen is caused.

[0012]

DISCLOSURE OF THE INVENTION The present inventor has earnestly studied to develop a new structure capable of solving the above various problems all at once, and a new method which has never been considered in the past. The present invention is proposed from such a viewpoint.

That is, as shown in FIGS. 6 (a) and 6 (b), the mechanism for gas / solid / liquid separation in the conventional upward flow sludge blanket type processing apparatus is as follows. The upward flow containing the components is directed to the swash wall 35 or the drift block 3
It is basically taken out as treated water, which is made to have a non-uniform flow in 6 to contain as little gas and solid components as possible. In addition, the proposal of the type using the floatable filter media shown in FIGS. 6 (c) and (d) also ensures that the solid components contained in the water are further removed from the water in which the gas / solid components are contained as little as possible due to this drift. The purpose is to prevent it from flowing downstream.

However, this type of
Although the liquid separation mechanism has a complicated structure, there is a limit to the separation of gas, solid, and liquid, and at the same time, it is possible to prevent clogging while simultaneously preventing SS from flowing out due to load fluctuations. It's extremely difficult.

Therefore, the present inventor uses a screen having a great difference in the permeability of liquid (filterability) and the permeability of gas, as a structure completely different from the conventional gas / solid / liquid separation mechanism. Therefore, it has been found that it is possible to provide an upflow type biological wastewater treatment apparatus having a gas / solid / liquid separation mechanism capable of exhibiting a novel and excellent effect which has not been present in the past, and the present invention based on such findings It has reached the point where

[0016]

In order to achieve the above-mentioned object, the present inventor has completed the invention described in each of the claims.

That is, in the upflow sludge blanket type wastewater treatment apparatus of the present invention, the gas-liquid separating means has a screen in which a large number of long fibers are aligned in parallel in the thickness direction, It is characterized in that a part of the water surface in the treatment tank is stretched so as to surround it from below the water surface to above the water surface, and the treated water extraction means is provided in the water area surrounded by this screen. ..

The granulated sludge layer in the treatment tank is fluidized by the upward flow to form a sludge blanket layer.

The screen described above shows a large difference in properties between water and gas by being wet with water, and in water, solids contained in water are prevented from passing, but in gas, gas is allowed to permeate. However, in practice, such a net is not suitable, and as described above, many long fibers are drawn in parallel in the lateral direction while overlapping in the thickness direction. It is necessary to have a uniform structure. The reason is that, although the net-shaped screen is effective as a filtering means, it has a shorter time than a screen in which a large number of long fibers used in the present invention are aligned in the lateral direction in a state of overlapping in the thickness direction. This is because there is a drawback that clogging occurs in the interior and the cleaning for removing the clogging cannot be easily performed by bubbling gas.

The screen used in the present invention, in which a large number of long fibers are aligned in parallel in the transverse direction in the state of overlapping in the thickness direction, is not particularly limited in the material of the long fibers. Various kinds of fibers such as fibers and polypropylene fibers can be used. However, considering the regenerative treatment of fibers by chemicals, use fibers with excellent acid resistance and chemical resistance such as acrylic fibers and polypropylene fibers. Is preferred. The long fiber has, for example, a thickness of 10 to 10.
Single fibers of about 100 μm are aligned to form a bundle of long fibers, which are aggregated so as to prevent passage of solid components in water, for example, 1 to 10 kg-dry / m ² per horizontal section of the tank, and 0 A material that can prevent passage of granules of about 3 to 0.5 mm, and preferably smaller than that, is preferable.

The screen is stretched so that one U-shape or V-shape is formed between a pair of opposing wall surfaces of a processing tank having a rectangular cross-section, or the U-shape or V-shape continues a plurality of times. A typical configuration may be one stretched in this manner.

The means for taking out the treated water is not particularly limited,
For example, a conventionally known one such as an overflow type using a trough can be used.

The device may be provided with means for cleaning the screen. In the device of the present invention, since the screen is configured as a set of long fibers which are not bound to each other, the bubbling of bubbles allows the adjacent fibers to move randomly, which causes the solids trapped in the fiber bundle to move. The components are easily removed. Therefore, with this bubbling, the screen can be effectively cleaned. For bubbling such a cleaning gas,
It is preferable to circulate and use the gas (methane gas) generated in this treatment tank.

The apparatus of the present invention is used as a part of the equipment which is provided with, for example, an aerobic microorganism treatment apparatus, a precipitation apparatus and the like in the latter stage, as in the conventional case.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail below with reference to the drawings. Example 1 In FIG. 1, 1 is a treatment tank, which is composed of a vertically long closed container having a rectangular horizontal cross section, and a granule sludge layer 2 is filled in the lower part of the tank. 3 is this processing tank 1
It is a raw water (organic wastewater) supply pipe connected to the lower part of the.

A gas-liquid separation mechanism is provided on the upper part of the processing tank 1. The gas-liquid separation mechanism in this example is formed in a V shape between a pair of side walls facing each other of the processing tank 1. It is formed by stretching a screen 4 in which long fiber bundles are aligned, and the upper ends of both sides of this V-shape are located above the water surface, and the central lower end is located below the water surface. In addition, the screen 4 has a density (1) which is sufficient to prevent passage of solid components (SS components, etc.) contained in the water.
The long fiber bundles are aligned at 10 kg-dry / m ² ). On the surface of water, gas can freely pass through this screen.

Reference numeral 5 denotes a trough for extracting treated water provided on the water surface located above the screen in the water area in the central portion of the screen 4, and the solid floating with the gas is filtered by the screen 4 and these solids are filtered. Clear water that is substantially free of components is extracted as treated water.

Reference numeral 6 denotes a gas extraction pipe for extracting methane gas, which is connected to the upper part of the processing tank, and is connected to a gas reservoir 9 of a gas holder 8 via a desulfurization device 7.

Reference numeral 10 is a gas blow-out pipe arranged near the lower end of the screen 4 on the side of unfiltered water. The gas in the gas reservoir 9 of the gas holder 8 is sent by the cleaning blower 11 to clean the screen. It is supposed to blow out. Cleaning is performed at appropriate intervals by a controller (not shown).

According to the wastewater treatment apparatus using the anaerobic microorganisms having the above-mentioned structure, the raw water supplied from the lower part of the treatment tank flows upward in the tank at a predetermined flow rate to fluidize the granule sludge layer 2. Then, a sludge blanket layer is formed, and organic substances are efficiently decomposed by contact with anaerobic microorganisms. And the water that has passed through this sludge blanket layer is further upward, and the upward flow velocity for fluidization of the sludge layer is set so that many sludge pellets that have risen with bubbles settle in the middle, Bubbles contained in water,
And the solid components with some remaining bubbles reach the position of the screen 4. Since the solid component cannot pass through the screen 4, it rises along the membrane surface of the screen to both sides of the illustrated tank 1. On the other hand, since water can pass through the screen 4, it also rises in the central area of the illustrated tank 1.

Bubbles in the water reaching the surface of the water can escape from the water and freely pass through the screen 4 on the surface of the water. Therefore, one methane gas reservoir 12 is formed in the entire upper part of the tank, and a gas extraction pipe is formed. From 6, it is sent to the gas holder 8.

On the other hand, from the trough 5 provided on the water surface on the filtered water side above the screen 4, the treated water in which the solid components have been filtered is extracted out of the treatment tank 1 to obtain a treated water with high clarity. You can

Example 2 In this example shown in FIG. 2, in a large-scale processing tank 101, a screen 104 made of the above long fiber bundles is formed by repeating a V-shape a plurality of times between a pair of side walls of the tank. It is characterized in that it is stretched, and the other configurations are the same as those of the above-mentioned embodiment. Therefore, common components are shown by adding 100 to the reference numerals of the first embodiment, and detailed description is omitted. Also in the processing tank 101 in this example, the methane gas reservoir 112 formed in the upper part of the processing tank is substantially one because the gas can freely pass through the screen 104. Also in this example, as in the case of Example 1, it is possible to obtain the excellent filtering effect of the solid component, and it is possible to obtain the treated water with high clarification degree of the treated water quality.

Embodiment 3 FIGS. 3 and 4 show, as another embodiment of the present invention, the construction of an apparatus in which a screen 204 made of long fibers is stretched in a U-shape. The screen 204 in this example is clamped and fixed with bolts 222 at both ends by a pair of sandwich plates 220 and 221 respectively provided on the upper ends of the opposing wall surfaces in the upper part of the tank, and the middle part is hung down in the tank by the holding frame 223. It has a substantially U-shape. According to this example, since the length of the screen below the water surface is extended, the filtration area becomes large as compared with the case where the screen is extended in a V shape, which is advantageous.

Test Example 1 Using the apparatus shown in FIG. 1, when treating wastewater in a food factory (average COD _Cr concentration is about 2000 mg / l), the pH of which was adjusted to around 7 was used as raw water under the following conditions: The anaerobic microbial treatment was carried out and the daily change of the outflow SS was measured.

The apparatus is such that a bundle of 43 μm acrylic fibers (100,000 pieces / unit) is placed in a treatment tank of 1 m × 1 m × 4 m (H).
The bundle is spread to 2 m to make one sheet, and eight sheets are piled up to make a screen (fiber packing density per unit volume: 2.8 kg-
dry / m ² ) was stretched.

Further, two gas blow-out tubes horizontally extending along the lower side of the screen were perforated downward at a distance of 330 mm and having a diameter of 4 mm so that one side of the V-shaped screen could be washed. Then, two diaphragm type cleaning pumps (air amount of 85 liters / min) were used to perform cleaning twice a week for 5 minutes on each side (cleaning gas LV = 10 m /
h).

A COD _Cr load of 10 kg-COD _Cr / m ³
The test result when / d is shown in the graph of FIG. 5 (indicated by a + point in the graph).

For comparison, the same test was performed except that the gas-liquid separation mechanism was changed to (a) in FIG. 6, and the daily change of outflow SS was measured.

The test results are shown in the graph of FIG. 5 (indicated by the square points in the graph).

From this result, a load of 10 kg-COD _Cr /
The COD _Cr removal rate in m ³ / d is 75% or more, and as is clear from FIG. 5, when the apparatus of the present invention is used, SS in the treated water extracted from the treatment tank is
It was confirmed that it was lower than that of the conventional device. Therefore, if the SS outflow rate is allowed to the same extent as in the conventional apparatus, it means that the upward flow velocity for fluidizing the granule sludge layer can be set relatively high,
It is effective in improving the contact efficiency of microorganisms and organic substances by fluidization, and thus in improving the treatment efficiency.

[0042]

According to the apparatus of the present invention, the SS component in the water, the suspended sludge and the bubble-shaped methane gas cannot pass through this screen in the portion where the screen is submerged, and the screen is inclined. Floating along the stretched screen to the surface of the water, on the other hand, the water flows upward without being blocked by this screen, so the treated water is stretched from below the surface to above the surface. It makes a big difference in the state. That is, the water in the water area where the screen is located below the water surface contains almost no gas and solid components, while the water in the water area where the screen is located above the water surface contains the gas and solid components. Therefore, it is possible to take out treated water having an extremely small amount of SS component from the former water area, and since methane gas is not blocked from passing through the screen on the water surface, the upper portion of the treatment tank can be withdrawn as one gas reservoir from here. Therefore, with a very simple device configuration in which a screen having a large difference in properties between below and above the water surface is used, the conventional complicated mechanism as shown in FIGS. Compared with the conventional separation of gas, solid, and liquid, it has an excellent effect that extremely efficient and reliable separation of gas, solid, and liquid can be performed.

Further, the apparatus of the present invention has a very simple structure in which the fiber bundles in which long fibers are aligned are closely arranged in parallel in the upper part of the processing tank, and moreover, in order to extract the methane gas, the gas phase above the processing tank is required. Since it is only necessary to connect a gas vent pipe to the portion, a special configuration is not required incidentally, and the installation cost of the device is low, and the renewal and replacement by cleaning are easy, which is an excellent effect.

Further, since the apparatus of the present invention is excellent in the filtering action of the solid component in the gas-liquid separation mechanism, it is less likely that the solid component is contained on the filtration side, and therefore the granulated sludge layer is fluidized. The controllable range of the flow velocity of
This has the effect of improving the contact efficiency of microorganisms and organic substances, and thus improving the treatment efficiency.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a schematic configuration of a device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a schematic configuration example of an apparatus according to a second embodiment of the present invention.

FIG. 3 is a perspective view of a screen extending portion according to a third embodiment of the present invention.

FIG. 4 is a schematic side view of the third embodiment.

FIG. 5 is a diagram showing a state of daily change of outflow SS of the device of the present invention shown in FIG. 1 and the conventional device shown in FIG. 6 (a).

6 (a) to 6 (d) are views for explaining a gas / solid / liquid separation mechanism of a conventional device.

[Explanation of symbols]

1 ... Treatment tank, 2 ... Granule sludge layer, 3 ...
-Raw water supply pipe, 4 ... Screen, 5 ... Trough for extracting treated water, 6 ... Gas extraction pipe, 12 ... Methane gas reservoir.

Claims (4)

[Claims] 1. A treatment tank filled with a granule sludge layer of anaerobic microorganisms, a wastewater supply means for supplying untreated wastewater from the lower side of the granule sludge layer of the treatment tank, and a treatment tank provided above the treatment tank. And a gas-liquid separation means for separating the gas contained in the water that has passed upward through the granule sludge layer from the water, and a treated water removal means for taking out the gas-liquid separated water from the treatment tank. In the upflow sludge blanket type wastewater treatment apparatus provided with, the gas-liquid separation means is a screen formed by arranging a number of long fibers in parallel in the state of overlapping in the thickness direction. It is formed by stretching a part of the water surface so as to surround it from below the water surface to above the water surface, and the treated water extraction means is provided in a water area surrounded by this screen. Flow sludge blanc Tsu door type of waste water treatment equipment. 2. The screen according to claim 1, wherein the screen is stretched in a U-shape or a V-shape between a pair of opposing wall surfaces of the processing tank, or the screen is stretched so that the U-shape or the V-shape continues a plurality of times. Upflow sludge blanket type wastewater treatment equipment, which is characterized by being installed. 3. The cleaning gas blow-out pipe according to claim 1, wherein a cleaning gas blowing pipe for bubbling a gas for cleaning the screen is provided near the lower side of the screen located below the water surface. Flow sludge blanket type wastewater treatment equipment. 4. The upflow sludge blanket type wastewater treatment device according to claim 3, wherein the cleaning gas is a gas in which methane gas generated from the wastewater treatment device is circulated.