JPH0326397A - Waste water treating device - Google Patents

Abstract

PURPOSE:To obtain the device with which the treatment efficiency is enhanced and the running and maintenance costs are reduced by providing the suction and discharge ports of a pipe in a reaction vessel, connecting a pressurizing means to the upper part of the pipe and connecting a means for exhausting a gas in a pressurized chamber and agitating a liq. mixture in the vessel. CONSTITUTION:The inside of the pipe 15 is pressurized by a booster pump 24 constituting a pressurizing means 16 to form the pressurized chamber 17 at all times at the upper part of the pipe, a valve 25 constituting an evacuating means 18 is opened at regular time intervals, hence the pressurized chamber 17 is intermittently exhausted, and a liq. mixture 9 in the vessel close to its bottom 1a is intermittently sucked into the pipe 15. Consequently, the liq. mixture 9 close to the bottom 1a is intermittently agitated, the dead space is effectively broken by the dynamic pressure, and efficiency in treating waste water is improved. The power cost is low as compared with the method in which waste water is forcedly circulated in the reaction vessel 1, and the running and maintenance costs are drastically reduced.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a wastewater treatment technology that treats organic wastewater using biochemical reactions, and in particular, a technology that can effectively stir sludge in a reaction tank. It is installed in wastewater treatment equipment.

[Prior Art] Generally, biochemical treatment is used as a method for treating organic wastewater discharged from factories or households.

A wastewater treatment apparatus using this treatment method processes organic matter in wastewater by decomposing or digesting it using microorganisms, and the IN method shown in FIG. 2 is known.

In FIG. 2, 1 is a reaction tank. Inside this reaction tank 1, a sludge layer 2 containing microorganisms is formed. Wastewater 3
is supplied to the tank inner bottom 1 via the inflow pipe 4 by the raw water pump 14.
a and is purified while passing through the sludge tank 2. The purified water 5 overflows from the overflow weir 6 at the upper end of the reaction tank 1, is received by the overflow gutter 7, and is discharged.

In addition, a gas recovery dome l1 is provided at the upper part of the reaction tank 1 to collect gas vacuoles such as methane gas generated by the decomposition of organic matter in the waste water 3, and below the dome l1, the gas vacuoles are guided to the gas recovery dome 11. A rectifying fluid 12 is provided for this purpose. The gas recovery dome 11 is formed at an angle from the inner surface of the reaction tank 1 toward the flow regulator 12, and has a biogas pipe 13 connected to its upper end. Gas cells such as methane generated in the sludge layer 2 rise in the mixed liquid 9 in the tank and are guided by the flow regulator 12 to the gas recovery dome 11111 and collected, passing through the biogas pipe 13 to a gas holder (not shown). ).

The reaction tank 1 is configured so that the sludge in the sludge layer 2 is stirred by the rise of gas pores such as methane, thereby effectively treating wastewater.

Therefore, when the concentration of organic matter in the wastewater 3 introduced into the tank 1 is high, the amount of gas pores generated due to the decomposition of the organic matter is large, so that the sludge is effectively agitated and the BOD removal rate is high. On the other hand, if the concentration of organic matter in wastewater is low (for example, BOD is 200 lg/
Jl), the amount of gas pores generated is small and the sludge stirring due to the rise of the gas pores is insufficient, resulting in a low BOD removal rate. In particular, the formation of a dead space D at the bottom of the reaction tank 1 that does not participate in the reaction due to sedimentation of sludge causes a significant reduction in the wastewater treatment capacity of the wastewater treatment device. Therefore, part of the purified water 5 is pumped to the bottom 1a of the reaction tank 1 by the circulation pump 8.
In some cases, the sludge is refluxed to generate an upward flow within the reaction tank 1 to prevent the sludge from settling.

[Problems to be Solved by the Invention] As described above, when the concentration of organic matter in the wastewater 3 flowing into the reaction tank 1 is low, the circulation pump 8 forms a high upward flow in the reaction tank 1 to prevent sludge from settling. can be prevented.

However, in this method, the purified water 5 that flows into the reaction tank 1 in order to keep the sludge layer 2 below the reaction tank 1 is
It is necessary to constantly control the flow rate of the wastewater treatment system, and the circulation pump 8 must be operated continuously, which has the drawback that the management and power costs significantly increase the operating and maintenance costs of the entire wastewater treatment system.

The present invention was created to solve the above problems,
The purpose is to provide a wastewater treatment device that has high treatment efficiency even when the concentration of organic matter in wastewater is low, and has low operating and maintenance costs.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a pipe body in a reaction tank for treating wastewater, and also provides a pipe body with its suction and discharge port facing the bottom of the tank. A pressurizing means is connected to the upper part of the body, and an exhaust means is connected to exhaust the gas in the pressurizing chamber formed in the upper part of the tube and to stir the mixed liquid in the tank.

[Operation] According to the present invention according to the above structure, a pressurizing chamber is formed in the upper part of the tube by the pressurizing means injecting gas into the tube,
The water level of the mixed liquid inside the pipe is lowered by the volume of the pressurized chamber. In this state, when the exhaust means exhausts the gas in the pressurized chamber, the water pressure of the mixed liquid in the tank causes the water level of the mixed liquid in the tube to rise rapidly to the original water level. At this time, the mixed liquid at the bottom of the reaction tank is sucked into the pipe from the suction/outlet port by the amount that the water level of the mixed liquid in the tube rises, so the mixed liquid in the tank is stirred by the flow pressure and is formed into settled sludge. Dead space will be destroyed.

[Example] Next, one embodiment of the present invention will be described with reference to FIG.

In the figure, a sludge layer '2 containing microorganisms such as methane bacteria is present in a reaction tank 1. Bottom part 1a of reaction tank 1
Inflow pipes 5 and 4 for inflowing wastewater 3 are connected at several locations. Further, at the upper end of the reaction tank 1, there is an overflow weir 6 for overflowing the purified water 5 as the supernatant of the mixed liquid 9 in the tank, and an overflow weir 6 for receiving the purified water 5 overflowing from the overflow weir 6. An overflow gutter 7 is provided, and this overflow gutter 7
An outflow pipe 10 is connected to discharge the purified water 6 to.

Furthermore, gas recovery domes 11 are arranged at equal intervals in the reaction tank 1 to receive and recover gas pores such as methane generated in the sludge tank 2 and rising in the mixed liquid 9 in the tank. At the same time, below the gas recovery dome 11, regulating fluids 12 for guiding gas cells to the gas recovery dome 11 are arranged at equal intervals so as to alternate with the gas recovery dome 11. The gas recovery dome 11 is connected via a biogas pipe 13 to a gas holder (not shown) for accommodating generated gas.

The above structure and the system in which the wastewater 3 introduced into the reaction tank 1 by the raw water pump 14 connected to the inflow pipe 4 is purified while passing through the sludge layer 2, and the supernatant water is discharged as purified water 5 are conventional techniques. It is similar to

6 The waste water purification device according to the present invention is equipped with means for sucking and discharging the tank mixed liquid 9 at the tank inner bottom 1a and stirring the tank mixed liquid 9. That is, a plurality of tube bodies 15 are arranged in the reaction tank 1 with their suction and discharge ports 15a facing the tank inner bottom 1a, and a pressurizing stage 16 for injecting pressurized gas into the tube bodies 15; An exhaust stage 18 is provided for exhausting the gas in the pressurized chamber 17 formed in the upper part of the tube by the gas injected into the tube 15 by the pressurizing means 16. The tube body 15 is arranged so that its upper end is higher than the overflow weir 6, and gas inlet and outlet pipes 19 are connected to the upper portion of the tube body.

Further, the suction/discharge port 15a is shaped such that its lower end portion is expanded in diameter toward the tank inner bottom portion 1a. The pipe body 15 is airtight except for the connection part with the gas inlet/outlet pipe 19 and the above-mentioned intake/exhaust port 15a. Each gas inlet/outlet pipe 19 has one header 20
This header 20 is connected to a gas storage tank 23 filled with an inert gas such as nitrogen through a gas pressure manifold 21 and a gas discharge pipe 22, and is connected to a gas storage tank 23 filled with an inert gas such as nitrogen.
A pressurizing pump 24 is provided to monitor the pressurizing means 16, and a valve 25 constituting the exhaust means 18 is provided in the gas exhaust pipe 22.

The pressurizing pump 24 constituting the pressurizing means 16 is connected to the gas storage tank 2.
3 is sent to the header 20 via the gas pressure pipe 21, and gas is injected at a constant pressure into each pipe body 15 via each gas inlet/output pipe 9 connected to the header 20, and the pipe body 1
Gas is injected into 5 at a constant pressure to push down the mixed liquid 9 in the tank in the tube body 15 to a preset water level to form a pressurized chamber 17 with a predetermined volume in the upper part of the tube body. After the pressurization chamber 17 is formed, the inside of the pressurization chamber 15 can be pressurized to the extent that the volume of the pressurization chamber 17 can be maintained.

On the other hand, the valve 25 constituting the exhaust means 18 is closed during normal operation of the wastewater treatment apparatus, and is configured to be opened at regular intervals by a timer or the like (not shown).

The inflow position of the waste water 3 may be directly below the suction/discharge port 15a of the pipe body 15, or may be between the suction/discharge ports 15a adjacent to each other as shown in FIG.

Next, the operation of this embodiment will be explained.

When the valve 25 constituting the exhaust means 18 is closed, by driving the pressurizing pump 24 constituting the pressurizing means 16, the gas in the gas storage ram 23 is pressurized and flows into the header 20. sent. The pressurized gas is further transmitted from the header 20 to each pipe body 15 via each gas inlet/output pipe 19.
injected into the body. As a result, a pressurizing chamber 17 is formed in the upper part of the tube, and the tank 1 in the tube 15 is filled by the volume of the pressurizing chamber 17.
The mixed liquid 9 is pushed out inside the pipe body 15, and the water level inside the pipe body 15 is lowered. The pressurizing pump 24 maintains the pressurizing chamber 17 in this state after the water level in the tubular body 15 has been lowered to a predetermined water level and the pressurizing chamber 17 has a predetermined volume.

In this state, when the valve 25 constituting the exhaust means 18 is opened by a timer or the like (not shown), the gas in the pressurized chamber 17 formed in the header 20 and in the upper part of each tube is discharged to the gas exhaust pipe 22. The gas is exhausted into the gas storage tank 23 through the gas storage tank 23. The water level of the mixed liquid 9 in the tank inside the pipe body 15 is forcibly pushed down by the pressurized gas in the pressurizing chamber 17.
Pressurization 9 When the gas in the chamber 17 is exhausted, the water pressure of the mixed liquid 9 in the tank causes the water level to rise rapidly to the original water level.

At this time, the mixed liquid 9 near the bottom 1a of the tank is sucked into the pipe 15 through the suction/discharge port 15a by the amount of rise in the water level of the mixed liquid 9 in the pipe 15, so the mixed liquid 9 in the tank is stirred by the flow pressure. The dead space D formed by the settled sludge is destroyed.

When the gas in the pressurized chamber 17 is exhausted, the valve 25 is closed,
The gas in the gas storage tank 23 is gradually injected into the pipe body 15 by driving the pressure pump 24 again, and the pressurization chamber 1 is formed in the upper part of the pipe body.
7 is restored and formed. Therefore, when the tank mixed liquid 9 sucked into the pipe body 15 returns to the reaction tank 1 again, it is gradually returned, so that the unmixed liquid due to the sudden increase in overflow load at the overflow weir 6 at the upper end of the reaction tank Spills can be avoided. in this way,
According to the apparatus shown in this embodiment, the pressurizing pump 24, which constitutes the pressurizing means 16, pressurizes the inside of the tube body 15 to constantly form a pressurizing chamber 17 in the vertical upper part of the tube, and constitutes the exhaust means 18. By opening the valve 25 at regular intervals, the inside of the pressurizing chamber 17 can be evacuated intermittently, and the mixed liquid 9 in the tank near the bottom 101a of the tank can be intermittently sucked into the pipe body 15. As a result, the mixed liquid 9 in the tank near the bottom 1a of the tank can be intermittently stirred, and the dead space can be effectively destroyed by the flow pressure, and the efficiency of wastewater treatment can be improved.

Further, the pressurizing pump 24 constituting the pressurizing means 16 has a pressurizing force to the extent that it pushes down the mixed liquid 9 in the tubular body 15 by a predetermined water level when forming the pressurizing chamber 17 in the upper part of the tubular body. You can use a small output one. In addition, the pipe body 15
When the mixed liquid 9 in the tank is sucked into the tank, the valve 25 is opened and the water level difference between the mixed liquid 9 in the tube body 15 and the reaction tank 1 is automatically used to draw in the mixed liquid 9 in the tank, so no separate driving device is required.

Therefore, compared to the conventional system in which purified water 5 is forcibly circulated within the reaction tank 1 using a circulation pump 8 or the like to agitate the inside of the reaction tank 1, the power cost is lower, and the operating cost of the entire wastewater treatment equipment is reduced. This has the effect of significantly reducing maintenance and management costs.

In addition, the pressurizing pump 2411 constituting the pressurizing stage 16 does not allow gas flow in the gas pressure man tube 22 even if its drive is stopped after the pressurizing chamber 17 of a predetermined volume is formed in the upper part of the tube body. It can be blocked! By adopting the R construction, the drive can be stopped except when gas is being injected into the pipe body 15, and power costs can be further reduced.

In this embodiment, the gas to be filled into the gas storage tank 23 is preferably an inert gas such as nitrogen, but it is also possible to use digestive gas or air.

[Effects of the Invention] In summary, according to the present invention, the following excellent effects are achieved.

(1) Since the treated liquid at the bottom of the reaction tank is intermittently sucked into the tube, the dead space formed by the sludge settling at the bottom of the reaction tank can be effectively destroyed.

(2) Wastewater treatment efficiency can be improved.

(3) Operating costs and maintenance costs can be significantly reduced.

12

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a block diagram showing a conventional example. In the figure, 1 is the reaction tank, 1a is the bottom of the tank, 9 is the mixed liquid in the tank,
15 is a tube body, 15a is an intake/exhaust port, 16 is a pressurizing means, 17 is a pressurizing chamber, and 18 is an exhaust means.

Claims (1)

[Claims] 1. A pipe body is arranged in a reaction tank for treating wastewater, and its suction and discharge ports are provided facing the bottom of the tank, and a pressurizing means is connected to the top of the pipe body, and a pressure means is formed at the top of the pipe body. A wastewater treatment device characterized in that an exhaust means is connected to exhaust gas in a pressurized chamber and agitate a mixed liquid in a tank.