JPH09220591A - Waste water treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a waste water treatment apparatus capable of continuing the good treatment even of waste water generating scum while holding the amt. of bacteria in a reaction tank and preventing generated scum from flowing out along with treated water to facilitate the discarding of scum. SOLUTION: A waste water treatent apparatus biologically purifying waste water in an unaerobic reaction tank 2 is constituted of the gas-solid-liquid separation device 6 arranged to the upper part of the reaction tank 2 and opened to the liquid phase part of the reaction tank at both ends thereof, the skimmer 9 arranged in the vicinity of the liquid surface of the upper part of the reaction tank 2 and a barrier plate 10 arranged in order to limit the generation place of sucm formed in the reaction tank 2 on the liquid surface. By generating the scum formed in the reaction tank 2 at a specific place by the barrier plate 10 to scrape off the scum by the skimmer 9 without pushing out the same to a flooding part, scum can be prevented from flowing out along with treated water to be easily discarded and treated water good in quality can be obtained.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a wastewater treatment apparatus for treating wastewater such as sewage and industrial wastewater with anaerobic microorganisms.

[0002]

BACKGROUND ART Anaerobic treatment is one of the methods for treating organic matter in wastewater such as sewage, industrial wastewater, and sludge. Anaerobic treatment has advantages that it can be applied to wastewater containing a high concentration of organic substances, that the amount of sludge generated is small, and that the fermentation gas is mainly composed of methane gas, so that energy can be recovered.

FIG. 8 is a block diagram of a sludge bed type anaerobic wastewater treatment device (UASB type) which is generally widely used. As shown in the figure, the wastewater is fed to the reaction tank 2 by the raw water pump 1.
Is supplied into the tank from below. The reaction tank 2 has a layer of sedimentable cells, and organic substances in the wastewater are decomposed while rising in the anaerobic microorganism layer 3. The decomposed organic matter becomes methane gas or carbon dioxide gas and rises in the supernatant liquid layer 4. The bacteria in the reaction tank 2 rise in the liquid phase of the reaction tank 2 due to the accompanying flow due to the attachment of the fermentation gas or the rise of the fermentation gas, but the gas-solid separation device 6 provided above the liquid phase of the reaction tank 2 etc. Is separated from the fermentation gas at the gas-liquid interface, and the supernatant liquid layer 4 is settled into the anaerobic microorganism layer 3. Due to the function of the gas-solid separation device 6, the amount of the bacterial cells in the reaction tank 2 is maintained, and good processing can be continued.

[0004] When treating wastewater containing a large amount of biodegradable organic substances such as lipids and proteins, scum is generated and accumulated at the gas-liquid interface in the reaction tank 2. The scum is a collection of fine bubbles having a holding power. When scum accumulates on the gas-liquid interface in the reaction tank 2, the bacterial cells that have risen in the supernatant layer 4 together with the fermentation gas adhere to the scum and accumulate in the anaerobic microorganism layer 3 without settling. Further, since the accumulated amount of scum flows out together with the treated water from the reaction tank overflow portion 5 along with the bacterial cells attached thereto, the bacterial cell retention amount in the reaction tank 2 decreases. As the number of bacterial cells decreases, the reaction tank 2 cannot be sufficiently treated. In order to solve such a problem, a wastewater treatment device having a skimmer or a shower installed in a reaction tank is used.

FIG. 9 is a schematic view of a conventional wastewater treatment apparatus equipped with a cylindrical reaction tank in which a skimmer is installed. As shown in the figure, a skimmer 9 is installed so as to scratch the liquid surface of the reaction tank 2, and the skimmer 9 is rotated by a motor 8 attached to the upper part of the reaction tank 2. The scum pocket 7 is installed so as to open slightly higher than the liquid surface of the reaction tank 2, and the skimmer 9
Only the scum that has been scraped by is scraped off into the scum pocket 7. The scum scraped off in the scum pocket 7 is taken out of the reaction tank 2 from the lower part and discarded. However, in this method, the skimmer 9 scrapes off a part of the scum to the overflow portion 5, which causes the deterioration of the treated water quality. Further, the scum has a very poor dehydration property and cannot be easily reduced in volume by a dehydrator, so that it is difficult to dispose of it.

FIG. 10 is a schematic view of a conventional wastewater treatment apparatus equipped with a cylindrical reaction tank equipped with a shower. As shown in the figure, a shower nozzle 12 is provided on the ceiling of the reaction tank 2, and fresh water is jetted to destroy the scum or to give an impact to the scum to separate the adhered bacterial cells. However, this method has a problem in that when the amount of scum generated is large, the amount of fresh water required is also large and therefore it is too expensive. The reason for using clear water is to avoid clogging of the nozzle when suspended solids and the like are mixed in the shower water.

[0007]

SUMMARY OF THE INVENTION Claims 1 to 6 of the present invention have been made in view of the above circumstances, and the purpose thereof is to reduce the outflow of scum into the treated water, and to use fermentation gas or scum. Wastewater that improves separability from bacterial cells and keeps the amount of bacterial cells in the reaction tank even in wastewater where scum is generated so that good processing can be continued, and at the same time reduces the volume of scum generated and separates it to facilitate disposal. It is to provide a processing device.

[0008]

In order to achieve the above object, the first aspect of the present invention is to provide a wastewater treatment apparatus for biologically purifying wastewater in an anaerobic reaction tank. Installed gas-solid separation device with both ends open to the liquid phase part of the reaction tank, a skimmer installed near the liquid surface above the reaction tank, and a liquid level of scum generated in the reaction tank. It is characterized by being configured with a baffle installed to limit the place of occurrence.

According to a second aspect of the present invention, in a wastewater treatment apparatus for biologically purifying wastewater in an anaerobic reaction tank, the wastewater treatment apparatus is installed above the reaction tank, and both ends are opened to a liquid phase portion of the reaction tank. Gas-liquid separation device, a water spouting device installed in the gas phase of the reaction tank, and purification for removing suspended solids of the waste water purified to use part of the waste water purified in the reaction tank for fountain And a device.

According to a third aspect of the present invention, in the wastewater treatment apparatus according to the first aspect, there is provided a tank for storing scum scraped by a skimmer in the reaction tank and defoaming the scum by a decompression device. To do.

In the wastewater treatment apparatus according to claims 4 and 1 of the present invention, a scum scraped by a skimmer is stored in the reaction tank, and a tank for defoaming the scum with a defoaming agent is provided. To do.

According to a fifth aspect of the present invention, in the wastewater treatment apparatus according to the first aspect, there is provided a tank for storing scum scraped by a skimmer in the reaction tank and heating the scum to defoam the scum. Characterize.

According to a sixth aspect of the present invention, in the wastewater treatment apparatus according to the first aspect, there is provided a tank for storing scum scraped by a skimmer in the reaction tank and treating the scum with a microorganism suitable for lipid decomposition. Is characterized by.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a first embodiment (corresponding to claim 1) of the anaerobic water treatment apparatus of the present invention.

In the figure, the main structure of the anaerobic water treatment apparatus is a reaction tank 2, and this reaction tank 2 decomposes organic substances in waste water to generate biogas, and an anaerobic microbial layer 3 and a supernatant layer 4. Consists of. Waste water is sent from the raw water pump 1 to the reaction tank 2
After flowing in from the bottom of the plant and being purified by the anaerobic microbial layer 3,
After passing through the supernatant layer 4, the overflow portion 5 flows out of the reaction tank 2.
Organic substances in the wastewater are decomposed into biogas mainly composed of methane and carbon dioxide by anaerobic microorganisms, rise in the reaction tank 2, and are recovered from the upper portion of the reaction tank 2.

A gas-solid separation device 6 is provided in the upper part of the reaction tank 2.
Is installed, and as the biogas rises, the supernatant layer 4
The part of the anaerobic microorganisms having risen in temperature is caused to collide with the gas-solid separation device 6 to settle into the anaerobic microorganism layer 3.

When the wastewater contains a large amount of lipids and proteins, the bubbles of biogas are less likely to burst and scum is formed on the liquid surface. In order to remove this scum, a scum pocket 7 and a skimmer 9 which is rotated by a motor 8 attached to the upper part of the reaction tank 2 are installed near the water surface above the reaction tank 2. By the rotation of the skimmer 9, the scum on the water surface is scraped off by the scum pocket 7. Further, a scum baffle plate 10 is installed between the skimmer 9 and the overflow portion 5 so that the scum is generated and stays in a range where it can be scraped by the skimmer 9.

FIGS. 2A and 2B are a plan view of the liquid surface of the reaction tank 2 and an enlarged view of the upper portion of the reaction tank 2 in FIG. 1, respectively. As shown in the figure, the gas-solid separation device 6 is shaped so that scum is generated in the scum baffle plate 10 and the generated scum is scraped off to improve the quality of treated water from the overflow portion 5. It is the one.

FIG. 3 is a block diagram of a second embodiment (corresponding to claim 2) of the anaerobic water treatment apparatus of the present invention, which is the first shown in FIG.
The same parts as those in the embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in the figure, in this embodiment, the reaction tank 2
A part of the waste water purified in (1) is clarified by the clarification filtration tank 11, and this is sprayed as shower water from the shower nozzle 12 to the scum generated in the reaction tank 2 to destroy or impact the scum. If scum accumulates and becomes layered, it causes processing obstacles such as adhesion of anaerobic microorganisms, so crushing with a shower is effective. In addition, if a portion of the wastewater purified without using fresh water (usually tap water) is used for the shower, it will lead to cost reduction.

FIG. 4 is a block diagram of a third embodiment (corresponding to claim 3) of the anaerobic water treatment apparatus of the present invention, which is the first shown in FIG.
The same parts as those in the embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in the figure, in this embodiment, the first
The scum tank 13 is additionally installed in the embodiment. The scum scraped from the scum pocket 7 is received by the scum tank 13, and the inside of the scum tank 13 is decompressed by the vacuum pump 14, so that the scum volume can be reduced and disposal can be facilitated. Since scum is a collection of fine bubbles,
When defoaming, the volume is reduced. Further, when the atmospheric pressure is lowered, the bubbles expand and cannot maintain the film, and the bubbles are broken, so that the scum volume is reduced.

FIG. 5 is a constitutional view of a fourth embodiment (corresponding to claim 4) of the anaerobic water treatment apparatus of the present invention, and the third embodiment shown in FIG.
The same parts as those in the embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in the figure, in the fourth embodiment, the vacuum pump 14 is used to reduce the pressure to reduce the scum volume, but in the present embodiment, the defoaming agent nozzle 15 is installed above the scum tank 13. is there. According to this embodiment, the scum pocket 7
By spraying the defoaming agent from the defoaming agent nozzle 15 into the scum tank 13 containing the scum scraped off from the scum, the scum is broken and the volume is reduced.

FIG. 6 is a constitutional view of a fifth embodiment (corresponding to claim 5) of the anaerobic water treatment apparatus of the present invention, and shows a third embodiment shown in FIG.
The same parts as those in the embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in the figure, in the third embodiment, the scum volume was reduced by reducing the pressure, but in this embodiment, the scum tank 1 is used.
The steam line 16 for injecting steam into the 3 is installed. According to the present embodiment, steam is blown into the scum tank 13 from the steam line 16 to heat and expand the scum to break the bubbles and reduce the volume.

FIG. 7 is a constitutional view of a sixth embodiment (corresponding to claim 6) of the anaerobic water treatment apparatus of the present invention, and the third embodiment shown in FIG.
The same parts as those in the embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in the figure, in the third embodiment, the volume of scum is reduced by mechanical operation. In this embodiment, microorganisms suitable for scum decomposition are held in the scum tank 13,
The scum-decomposing bacteria layer 17 decomposes and removes scum to reduce the volume.

[0029]

As described above, the present invention has the following effects. That is, according to claim 1 of the present invention, scum generated in the reaction tank is generated at a specific location by the baffle plate, and the scum is scraped together with the treated water by scraping off with a skimmer without pushing it out to the overflow portion. Good treated water quality can be obtained because it can be prevented from flowing out and easily discarded.

According to the second aspect of the present invention, the shower water jetted for treating the separation of scum and bacterial cells removes suspended solids and the like from a part of the waste water produced in the reaction tank by a purifying device. Since the liquid for the shower is used by clarifying the purified waste water instead of newly using the fresh water, the cost of the fresh water and the increase of the cost due to the increase of the discharged water can be reduced.

According to the third aspect of the present invention, the scum scraped by the skimmer is stored in the upper part of the reaction tank, and the gas phase part is depressurized by the depressurization pump to reduce the volume of the scum and facilitate disposal.

According to the fourth aspect of the present invention, the scum scraped off by the skimmer in the upper part of the reaction vessel can be defoamed by adding the defoaming agent, and the scum can be reduced in volume to facilitate disposal. According to the fifth aspect of the present invention, by storing the scum scraped by the skimmer in the upper part of the reaction tank and heating the scum, the scum can be reduced in volume and can be easily discarded.

According to claim 6 of the present invention, the scum scraped by the skimmer in the upper part of the reaction tank and stored therein is treated with a lipid-degrading bacterium suitable for decomposing the scum to reduce the volume of the scum and facilitate disposal. can do.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment of a wastewater treatment device of the present invention.

FIG. 2 is a partially enlarged view of the upper part of the reaction tank 2 in FIG.

FIG. 3 is a configuration diagram of a second embodiment of the wastewater treatment apparatus of the present invention.

FIG. 4 is a configuration diagram of a third embodiment of the wastewater treatment apparatus of the present invention.

FIG. 5 is a configuration diagram of a fourth embodiment of a wastewater treatment device of the present invention.

FIG. 6 is a configuration diagram of a fifth embodiment of the wastewater treatment device of the present invention.

FIG. 7 is a configuration diagram of a sixth embodiment of the wastewater treatment apparatus of the present invention.

FIG. 8 is a configuration diagram of a conventional anaerobic water treatment device.

FIG. 9 is a configuration diagram of another conventional anaerobic water treatment device.

FIG. 10 is a configuration diagram of still another conventional anaerobic water treatment device.

[Explanation of symbols]

1 ... Raw water pump, 2 ... Reaction tank, 3 ... Anaerobic microbial layer, 4
… Supernatant layer, 5… Overflow part, 6… Gas-solid separation device, 7… Scum pocket, 8… Motor, 9… Skimmer, 10… Scum baffle plate, 11… Clarification filtration tank, 12… Shower nozzle,
13 ... scum tank, 14 ... vacuum pump, 15 ... defoaming nozzle, 16 ... steam line, 17 ... scum separation bacterial tank, 1
8 ... Gas trap.

 ─────────────────────────────────────────────────── --- Continuation of front page (72) Nobuyuki Ashikaga Nobuyuki Ashikaga 1st Toshiba Town, Fuchu, Tokyo Inside the Toshiba Fuchu factory (72) Inventor Hiroshi Tamura 1-1-1, Shibaura, Minato-ku, Tokyo Toshiba Headquarters Co., Ltd. In the office (72) Inventor Ichiro Yamanashi 1st Toshiba Town, Fuchu City, Tokyo Inside the Fuchu Factory, Toshiba Corporation

Claims (6)

[Claims] 1. A wastewater treatment device for biologically purifying wastewater in an anaerobic reaction tank, the gas-solid separation apparatus being installed above the reaction tank and having both ends open to a liquid phase portion of the reaction tank. And a skimmer installed near the liquid surface above the reaction tank, and a baffle installed to limit the location of scum generated in the reaction tank on the liquid surface. Wastewater treatment equipment. 2. A wastewater treatment device for biologically purifying wastewater in an anaerobic reaction tank, the gas-solid separating apparatus being installed above the reaction tank and having both ends open to a liquid phase portion of the reaction tank. And a fountain device installed in the gas phase portion of the reaction tank, and a purifying device for removing suspended solids of the waste water purified for using a part of the waste water purified in the reaction tank as a fountain. A wastewater treatment device characterized by the above. 3. The wastewater treatment device according to claim 1,
Store the scum scraped by the skimmer in the reaction tank,
A wastewater treatment device comprising a tank for defoaming the scum by a decompression device. 4. The wastewater treatment device according to claim 1,
Store the scum scraped by the skimmer in the reaction tank,
A wastewater treatment device comprising a tank for defoaming the scum with an antifoaming agent. 5. The wastewater treatment device according to claim 1,
Store the scum scraped by the skimmer in the reaction tank,
A wastewater treatment device comprising a tank for defoaming the scum by heating. 6. The wastewater treatment device according to claim 1,
Store the scum scraped by the skimmer in the reaction tank,
A wastewater treatment device comprising a tank for treating the scum with a microorganism suitable for lipid decomposition.