JPS60220194A - Anaerobic treatment apparatus - Google Patents

Abstract

PURPOSE:To make the titled apparatus compact and to perform the stable operation thereof for a long period of time, by providing a means, which floats and separates sludge by using the digestion gas of an anaerobic reaction tank, in said reaction tank provided above a reaction part. CONSTITUTION:Raw water enters a reaction tank 1 from an introducing pipe 2 and stayed in a sludge blanket 5 to receive anaerobic treatment and org. substances are gradually decomposed to digestion gas based on methane and carbon dioxide. The treated solution comes out from the sludge blanket 5 and gradually rises in the tank 1 to enter a separation chamber 6 while sludge contained in the solution is floated and separated by gas blown from an air diffusion pipe 9 to be converted to scum 15 which is, in turn, returned to the sludge blanket 5 through a bell mouth 12, a pipeline 11 and a pump 13. The treated water after separation is discharged from a pipe 3 and a part of the generated digestion gas is pressurized to be utilized as floating and separaing gas.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an anaerobic treatment device, and in particular, sludge in treated water of an anaerobic reaction tank is subjected to pressure flotation separation using the digestion gas of the reaction tank to perform an anaerobic reaction. The present invention relates to an anaerobic treatment device configured to be returned to the department.

[Background of the invention] As is well known, anaerobic treatment is a process in which organic matter contained in a liquid to be treated (hereinafter referred to as raw water), such as industrial wastewater or water sludge, is decomposed by anaerobic bacteria. Eventually, it is decomposed into scum (digested scum) such as methane, carbon dioxide, ammonia, and hydrogen sulfide.

In an anaerobic treatment apparatus that performs this anaerobic treatment, it is important to ensure a sufficient amount of sludge in the anaerobic reaction tank in order to perform stable treatment.

Therefore, a proposal has been made to install a pressurized flotation tank outside the reaction tank, perform pressure flotation separation on the mixed liquid flowing out from the anaerobic reaction tank, and return the separated sludge to the reaction tank. (For example, Japanese Patent Publication No. 55-17633, Japanese Patent Publication No. 55-15279.) However, if the pressurized flotation tank is installed separately from the anaerobic reaction tank, a large installation space is required, and the amount of heat dissipated increases. Heating costs for maintaining the anaerobic reaction tank at an appropriate reaction temperature also increase.

In addition, in a sludge blanket type reactor, it is important for good operation that the sludge in the reactor be turned into pellets or flocs with good settling properties. .

The conditions suitable for sludge conversion are not necessarily clear, but in a sludge blanket type reaction tank, the 75 sludge in the reaction tank becomes dispersed, the sludge settles for 41 minutes, and the sludge flows out of the system. There is.

Therefore, it has been considered to install a filler such as a honeycomb or corrugated plate, or an inclined plate type sedimentation separator at the treated water outflow part of the sludge blanket type reaction tank to prevent the sludge from flowing out of the system. However, such fillers and sedimentation separators only capture sludge, and if operated for a long period of time, there is a possibility that the fillers and sedimentation separators will become clogged with sludge. Furthermore, since it is basically impossible to return the captured sludge to the reaction tank, it was inevitable that the amount of sludge in the reaction tank would decrease.

[Objective of the Invention] The object of the present invention is to solve the problems of the above-mentioned conventional technology, and to provide a gas treatment which has a compact device, has a small amount of heat dissipated, has a low heating cost, and can operate stably for a long period of time. The goal is to provide equipment.

[Structure of the Invention] In order to achieve this object, the present invention provides a means for flotation separation using digested waste of the reaction tank in the anaerobic reaction tank above the core part of the reaction tank, and performs treatment of the reaction tank. The f''j mud of the water is separated by this flotation separation means and sent back to the reaction section.
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[Embodiments of the invention] Examples will be described below with reference to the drawings.

Figures p, t, and 1 are cross-sectional views of the individual packaging δ according to the present invention.

1 is an anaerobic reaction tank, a raw water introduction foil 2 is connected to the bottom, and a treated water discharge pipe 3 is installed at the top. This reaction tank 1 is a sludge blanket type anaerobic reaction tank, and a sludge blanket 5 is formed below the liquid 4 inside the reaction tank 1.

A pressurized separation chamber 6 or a separation plate 7 defines a region above the reaction section (in this embodiment, the sludge blanket 5) in the reaction tank 1.

At this time, the ceiling of the IIn chamber 6 is closed, and the digested waste extraction pipe 8 is connected. The bottom of the separation chamber 6 is open, and a blowout pipe 9 for blowing out fine bubbles for flotation and separation is provided at the bottom.

Digestion gas extracted from the extraction pipe 8 is supplied to the blow-off pipe 9 after being pressurized by a compressor 10 . Note that the separation chamber 6 is installed so that its lower part is immersed in the liquid 4, so that the liquid 4 in the reaction tank 1 naturally flows into the separation chamber 6 through the bottom opening of the separation chamber 6.

In the figure, reference numeral 11 denotes a pipe line having a pump 13 for returning the 115 sludge floating upward in the separation chamber 6 to the sludge blanket 5, and a part of the line 11 collects the floating sludge. A bell mouth 12 for suction is removed, and its -F portion is connected to a portion of the reaction tank 1.

14 in the figure indicates that the liquid in the reaction tank 1 is sludge 7
This is an outflow prevention plate to prevent the sludge from flowing directly into the discharge pipe 3, and to prevent the flow path between the separation plate 7 and the inner wall surface of the reaction tank 1 from shorting with the sludge blanket 5. It protrudes from the center/D side.

In the anaerobic treatment device configured as described above, raw water enters the reaction tank 1 through the introduction pipe 2, stays in the slanship plan tank 5, and undergoes anaerobic treatment, and the organic matter in the raw water is gradually converted into methane and carbon dioxide. It is broken down into digestive scum, mainly consisting of

The liquid that has been anaerobically treated in the sludge blanket 5 comes out of the sludge blanket 5, gradually rises inside the tank 1, and enters the separation chamber 6. Then, the sludge contained in the liquid in the separation chamber 6 is floated and separated by the sludge blown from the air shield pipe 9 into scum 15. This scum 15 is returned to the sludge blanket 5 via a bell mouth 12, a pipe line 11, and a pump 13.

On the other hand, the liquid from which sludge is separated in the separation chamber 6 becomes treated water.
The extraction is taken out from the bottom opening of the separation chamber 6, and the separation plate 7 and the reaction tank l are removed.
It passes between the inner wall surface and is discharged from the discharge pipe 3.

Note that methane and other scum generated by the gaseous decomposition reaction in the reaction tank 1 is extracted by the extraction pipe 8, and a part of it is pressurized by a compressor and used as the above-mentioned flotation separation gas, and the surplus is The gas is extracted from the system through the waste discharge pipe 16.

In such an anaerobic treatment device, the flotation separation chamber 6 is provided inside the reaction chamber 4al, so it is smaller and smaller than the conventional device in which the flotation separation layer is provided separately outside the reaction tank. In addition to being more compact, the heat dissipated from the flotation separation layer is also reduced accordingly, so the heating cost of the reaction tank is reduced.

Furthermore, unlike sludge trapping materials such as honeycombs and corrugated plates, the flotation separation chamber 6 is free from the risk of clogging with sludge, allowing stable operation of the apparatus for a long period of time.

Furthermore, even if the sludge does not settle well, it is sufficiently separated by pressurized flotation, so the amount of sludge flowing out of the system is reduced, and the system can be operated at a constant load.

In the above embodiment, either the digested scum is pressurized and blown out from the blow-off pipe 9, or the digested scum is pressurized and dissolved in the treated water to form pressurized water, and this pressurized water is sent from the blow-off pipe into the flotation separation chamber. You can also make it blow out.

The installation level of the blow-off pipe varies depending on the equipment capacity M, etc., but is usually about 1 to 2 meters below the water surface. In addition, the digestive gas blown out from the blow-off pipe is usually 2 to 5 kg.
/ cm' and is blown out. (Even when using pressurized water, 2-9□, 2-5K g/cm
' Pressurize to a certain degree. ) [Effects of the Invention] As detailed above, the aqueous treatment system of the present invention is provided with a sludge flotation separation means in the upper part of the inside of the reaction tank, and the installation space is saved in the connoux. Less is more. In addition, the amount of heat dissipated is small, and the heating cost is low. Then, it becomes possible to operate stably at the set load for a long period of time.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of the anaerobic treatment apparatus of the present invention. l...Anaerobic reaction tank, 5...Sludge blanket, 6...Pressure separation chamber, 8...φ gas extraction pipe, 9...Blowout pipe, 11...Sludge return pipe . Agent Patent Attorney Tsuyoshi Shigeno Figure 1

Claims (2)

[Claims] (1) An anaerobic reaction tank having a reaction section for anaerobically treating introduced raw water; and a pressurized flotation means for flotation-separating sludge in the reaction tank treatment liquid using digested waste from the anaerobic reaction tank. , means for returning the sludge separated by the pressure flotation means to the reaction section,
An anaerobic treatment apparatus characterized in that the pressure flotation separation means is provided in the anaerobic reaction tank and above the reaction section. (2) The anaerobic treatment apparatus according to claim 1, wherein the anaerobic reaction tank is a sludge blanket type sickle reaction tank.