JPH0440295A - Waste water treatment device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a wastewater treatment device for biologically treating domestic wastewater, industrial wastewater, and the like.

"Prior Art and Problems to be Solved by the Invention" One type of wastewater treatment equipment is equipment that implements an ultra-deep aeration method. As shown in FIG. 4, this device consists of a fluidized bed bioreactor 1 and a floating layer 2 connected thereto. The fluidized bed reactor 2 is an open type with an upper part communicating with the atmosphere, and its depth is 20 to 25 mm. Inside the reactor 1, there are a downward flow region 3 and an upward flow region 4. It is formed.

Organic wastewater is circulated and aerated within this fluidized bed reactor 1. The water to be treated in this fluidized bed reactor 1 is sent to a flotation tank 2, where activated sludge is separated, and then released.

In such a conventional wastewater treatment apparatus, there was a problem that sludge could not be sufficiently separated in the flotation tank 2.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a wastewater treatment device that can perform sludge separation in a flotation tank well and can operate smoothly.

"Means for Solving the Problems" The wastewater treatment apparatus of the present invention includes a pressurized fluidized bed bioreactor that biologically processes water to be treated while aerating and circulating it in a pressurized closed space. A flotation tank for separating suspended solids from the water to be treated is connected to the pressurized fluidized bed bioreactor through a liquid feed path equipped with a mechanism to reduce the pressure of the water to be treated passing through. The above object was achieved by providing a mechanism for controlling the water level within the reactor and a mechanism for controlling the pressure within the reactor.

The liquid feeding path can be configured by, for example, attaching a pressure reducing valve to a pipe line that communicates the reactor and the flotation tank. When the water supply channel is configured in this way, it is desirable that the pressure reducing valve be placed as close as possible to the location where suspended solids are to be separated, such as immediately before the flotation tank, directly below the flotation tank, or inside the flotation tank.

"Function" In this wastewater treatment device, the inside of the reactor is in a pressurized state, so a large amount of gas such as oxygen is dissolved in the water to be treated. As a result, the rate of purification by microorganisms is improved. FIG. 3 shows the results of an experiment conducted by the present inventors regarding the "influence of reactor internal pressure on processing capacity." As can be seen from this figure, under a pressure of 2 kg/cCG, the processing speed is approximately 5
It can be seen that the effect of increasing the processing efficiency due to pressurization is remarkable. Considering that in the general standard activated sludge process, the BOD volume load is 0.6 kg/m'/day, the processing capacity of the same volume glue actor under a pressure of 2 kg/cm'G is approximately 30 kg/m'/day. You can say it doubles.

As mentioned above, when the water to be treated in the pressurized water tank is depressurized in the water supply channel and sent to the flotation tank, the amount of gas that can be dissolved in the water to be treated decreases due to the depressurization. The gas that cannot be drained becomes fine bubbles and adheres to excess sludge and suspended solids (hereinafter referred to as 88 minutes) contained in the water to be treated. As a result, 88 minutes were floated and separated in the flotation tank.

The pressure inside this reactor is affected by fluctuations in the water level of the water to be treated, but this reactor is equipped with a water level control mechanism that keeps the liquid level within a certain range, so the pressure inside the reactor is The impact of water level fluctuations on water level can be suppressed. Since this wastewater treatment apparatus performs pressure control using the pressure control mechanism while keeping the water level in the reactor constant as described above, the pressure inside the reactor is stably maintained within an appropriate range.

"Example" Hereinafter, the wastewater treatment apparatus of the present invention will be described in detail with reference to the drawings.

(Embodiment 1) FIG. 1 shows an embodiment of the wastewater treatment apparatus of the present invention, in which reference numeral IO beam actor 1 11 is a flotation tank, and 12 is a liquid feeding path.

The reactor 10 is a pressurized fluidized bed type treatment tank that biologically processes the water while aerating and circulating the water under pressure.

This reactor 10 includes a sealed substantially cylindrical outer tank 13,
It is composed of an inner cylinder 14 placed in the center and an aeration pipe 15 placed below the inner cylinder 14, and the water to be treated in the reactor 10 contains bio-organisms in which a microbial film is supported on the particle surface. Particles are dispersed. The water to be treated in which the bioparticles are dispersed is supplied to the blower 1.
Due to the air lift effect of the air introduced into the reactor 10 from 8 through the aeration pipe 15, the air rises on the inside of the inner cylinder 14 and descends on the outside.

Biologically processed.

The upper part of the outer tank 13 is enlarged in diameter, and a bioparticle separation section 17 partitioned from the center by a partition tube 16 is formed in this enlarged diameter portion.

Organic wastewater collected and stored in a raw water tank 19 is supplied to this reactor 10 by a pump 20. A liquid level gauge 21 is provided in the bioparticle separation section 17.

These pump 20 and liquid level gauge 21 constitute a water level control mechanism.

The upper part of the outer tank 13 of this reactor 10 is sealed by a lid part 22, and this lid part 22 has a flow rate regulating valve 27.
A stationary gas venting pipe 28 is provided. The steady gas vent pipe 28 is used to steadily vent gas from the upper space of the reactor 10 with a constant valve opening.

The lid portion 22 of the reactor 10 further includes a reverse ratio valve 2.
A vent pipe 25 having a solenoid valve 24 and a solenoid valve 24 is attached. Moreover, a pressure gauge 26 is attached to the upper part of this reactor IO. These vent pipes 25 and pressure gauges 26 constitute a pressure control mechanism for this reactor lO, and when the pressure inside the reactor 10 reaches the upper limit pressure [10% increase over a predetermined pressure (for example, 2 kg/cm''G)]. The solenoid valve 24 is opened to vent air, and when the predetermined pressure returns, the solenoid valve 24 is closed.

The flotation tank 11 is a tank that separates suspended matter from the water to be treated that has been treated in the reactor 10. The inside of this flotation tank 11 is partitioned by a partition wall 29 into a suspended solid separation section 30 and a treated water introduction section 31.

The suspended solids separation section 30 and the treated water introduction section 31 are connected to a flotation tank l.
They are connected at the bottom side of O. The treated water conveyance section 31 includes
An overflow base 32 is provided, and the treated water from which suspended solids have been removed is discharged from this overflow base 32.

The liquid feeding path 12 connects to the suspended solid separation section 3 of the flotation tank 11.
0 and the bioparticle separating section 17 of the reactor 10. This liquid feeding path 12
is formed by a pipe, and there is a pressure reducing valve 3 in the middle of it.
4 is installed. A flow meter 19 is attached to this water supply channel 12 at a position inside the reactor 10 rather than the pressure reducing valve 34, and when the pressure reducing valve 34 is clogged and the flow velocity in the flow channel 12 decreases, the pressure reducing valve 34 is opened. Efforts are being made to eliminate clogging.

In this wastewater treatment equipment, from the raw water tank 19 to the pump 20
The water to be treated that is supplied to the reactor 10 is circulated through the reactor 10 together with bioparticles due to the air lift effect of the air blown from the aeration pipe 15, and is purified by the action of microorganisms. Since the inside of the reactor 10 is under pressure and the dissolved oxygen concentration is high, the water to be treated is quickly purified. Some of the oxygen in the blown air dissolves in the water to be treated, but the rest is released into the upper space of the reactor IO along with carbon dioxide gas generated during wastewater treatment, and released into the atmosphere from the steady gas vent pipe 28. be done. Since this steady gas vent pipe 28 performs gas venting at a constant speed, the pressure inside the reactor IO may reach the upper limit pressure. In that case, the solenoid valve 24 of the pressure control mechanism is released and the reactor 1 Reduce internal pressure.

The liquid level in the reactor IO is controlled by a water level control mechanism consisting of a pump 20 and a liquid level gauge 21 and a pressure reducing valve 34.
When the liquid level reaches the lower limit water level, the pump 20 is turned on and the raw water tank 19 is
The water to be treated is supplied into the reactor 1O, and when the liquid level reaches the upper limit water level, the pump 20 is turned off and the supply of the water to be treated is stopped.

The water to be treated in the reactor 10 as described above is sent from the bioparticle separation section 17 to the bottom of the suspended matter separation section 30 of the flotation tank 11 via the liquid feed path 12. Since the water to be treated that has passed through the pressure reducing valve 34 of the liquid supply path 12 is released from the pressurized state, some of the gases that cannot be dissolved in the water to be treated due to a decrease in solubility due to the decrease in pressure become fine bubbles. These microbubbles then adhere to the suspended 86 minutes.

When the water to be treated reaches the flotation tank 11, the 86 particles suspended in the water to be treated float to the water surface of the suspended solid separation section 30 due to the buoyancy of the attached bubbles.

The 86 minutes that floated to the surface are scraped up by a scraper (not shown) and removed as drawn sludge.

On the other hand, a small portion of the sludge that does not float and settles to the bottom is pulled out from the bottom as settled sludge. The treated water obtained by separating the 86 minutes in this way flows into the treated water introduction section 31 from below the partition wall 29 and is discharged over the overflow base 32.

In this wastewater treatment equipment, the water to be treated is pressurized or purified in the actor 10, so the dissolved oxygen concentration in the water to be treated is kept high, and the rate of purification of the water to be treated by aerobic microorganisms in the reactor 10 is increased. carried out with high efficiency. Therefore, according to this wastewater treatment apparatus, the volume of the reactor IO can be reduced without impairing the purification efficiency, and the apparatus can be made more compact.

In addition, in this wastewater treatment device, the water to be treated that has been treated in the reactor IO is sent to the flotation tank 11 via the liquid sending path 12 equipped with the pressure reducing valve 34, so that the water to be treated that has been in a pressurized state is transferred to the flotation tank 11. When the water passes through the pressure reducing valve 34 in the channel 12, it is released from the pressurized state, and fine bubbles of gas that cannot be dissolved are generated in the water to be treated. These microbubbles adhere to the 88 minute particles contained in the water to be treated, and are floated and separated in the flotation tank 11. Therefore, in this wastewater treatment device, 88 minutes is separated in a sufficiently concentrated state.

Furthermore, in this wastewater treatment apparatus, the reactor 10 is provided with a steady gas vent pipe 28 equipped with a flow rate adjustment valve 27, and a water level control mechanism consisting of a liquid level gauge 21 and a pump 20, a solenoid valve 24, and a pressure gauge 26. A pressure control mechanism is provided so that the reactor lO
The surplus of the aeration air that has passed through the water to be treated and the gas generated by wastewater treatment are transferred to the stationary gas vent pipe 2.
8 to the outside air at a constant rate to prevent sudden changes in the pressure inside the reactor lO. Furthermore, the water level of the water to be treated is maintained within a predetermined range by the water level control mechanism, thereby preventing the influence of water level fluctuations on the pressure inside the reactor IO. In this state, pressure control is performed by the pressure control mechanism, so that the internal pressure of the reactor 10 can be controlled within an appropriate range.

Therefore, according to this wastewater treatment device, the pressure in the reactor 10 can be stabilized within an appropriate range, and the device can be operated smoothly.

In addition, in this wastewater treatment device, a bioparticle separation section 17 is provided by expanding the diameter of the upper part of the reactor IO and partitioning it with a partition tube 16. Therefore, in the separation section 17, the flow of the water to be treated becomes gentle, and the bioparticles are covered. It is separated by sedimentation from the treated water.

Therefore, this wastewater treatment apparatus can prevent bioparticles from flowing into the liquid feeding path 12, and can operate without returning sludge (bioparticles) from the flotation tank 11.

(Example 2) FIG. 2 shows the main parts of a second example of the wastewater treatment apparatus of the present invention.

The wastewater treatment device of this example performs aeration using pure oxygen or high-concentration oxygen gas instead of air, and the gas in the upper space of the reactor IO is supplied to a circulation pipe having a de-dropper 36 and a valve 38. The air is returned to the diffuser pipe 15 via a passage 37. An oxygen tank (or oxygen gas generator) 39 is attached to the circulation pipe 37 via a valve 41 .

When the oxygen concentration meter 40 provided at the top of the reactor 10 detects that the oxygen concentration has fallen below a lower limit value (for example, 56%), the valve 41 of the oxygen tank 39 is opened. Furthermore, a gas vent valve 22 is provided at the top of this reactor IO in place of the steady gas vent pipe 28 provided in the device of Example 1.
As mentioned above, before replenishing oxygen gas from the oxygen tank 39, the gas vent valve 22 is opened for a short period of time to vent generated gas such as carbon dioxide gas and inert gas from the reactor lO. .

The wastewater treatment apparatus of this embodiment also provides the same effects as those of the first embodiment.

In addition, in the wastewater treatment apparatus of this example, reactor 1
It is also possible to adopt an operation method in which a carbon dioxide gas meter is installed in the upper space of the carbon dioxide gas and the gas vent valve 22 is opened and closed depending on the carbon dioxide concentration.

"Effects of the Invention" As explained above, the wastewater treatment apparatus of the present invention is a pressurized fluidized bed bioreactor that biologically treats water while aerating and circulating it in a pressurized closed space. A flotation tank that separates suspended solids from the water to be treated that has been treated in the reactor is connected via a liquid feeding path equipped with a mechanism for reducing the pressure of the water to be treated passing through, and the above-mentioned pressurized fluidized bed bio This is a device in which a reactor is provided with a mechanism for controlling the water level within the reactor and a mechanism for controlling the pressure within the reactor.

According to a wastewater treatment device with such a configuration, the water to be treated is pressurized or purified within the actor, so the dissolved oxygen concentration of the water to be treated is kept high and high purification efficiency is achieved. . Therefore, according to this wastewater treatment apparatus, the volume of the reactor can be reduced without impairing purification efficiency, and the apparatus can be made more compact.

In addition, in the wastewater treatment apparatus of the present invention, the water to be treated that has been treated in the reactor is depressurized and sent to the flotation tank, so when the water to be treated that was in a pressurized state passes through the liquid supply path, it is no longer pressurized. When released, microbubbles are generated in the water to be treated. These microbubbles then adhere to the 88 minute particles contained in the water to be treated. Therefore, in this wastewater treatment equipment, the flotation tank has a
8 minutes are separated by flotation and 88 minutes are separated in a sufficiently concentrated state.

Furthermore, since the wastewater treatment apparatus of the present invention is provided with a reactor water level control mechanism and a pressure control mechanism, the water level of the water to be treated is maintained within a predetermined range by the water level control mechanism, thereby reducing the influence of water level fluctuations on the pressure inside the reactor. The pressure inside the reactor can be controlled while preventing this. Therefore, according to the wastewater treatment apparatus of the present invention, the treated water quality, S
It is possible to stabilize the pressure inside the reactor, which has a large effect on S component separation efficiency, etc., and the device can be operated smoothly.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing the wastewater treatment device of Example 1, FIG. 2 is a schematic diagram showing the main parts of the wastewater treatment device of Example 2, and FIG. 3 is a schematic diagram showing the main parts of the wastewater treatment device of Example 2. FIG. 4 is a graph showing the results of ``Influence of Internal Pressure on Processing Capacity'' and is a schematic configuration diagram showing a conventional wastewater treatment device. 10. Reactor 11. Floating tank, 12. Water supply channel,
20...Pump, 21...Liquid level gauge, 24...Solenoid valve, 2
5...Air vent pipe, 26...Pressure gauge, 34...Pressure reducing valve.

Claims (1)

[Claims] A pressurized fluidized bed bioreactor that biologically treats water to be treated while aerating and circulating it in a pressurized closed space contains suspended solids from the water to be treated in the reactor. A flotation tank that separates the water is connected via a liquid feeding path equipped with a mechanism to reduce the pressure of the water to be treated passing therethrough, and the pressurized fluidized bed bioreactor is provided with a mechanism for controlling the water level in the reactor; A wastewater treatment device characterized by being equipped with a mechanism for controlling the pressure inside the reactor.