JPH0127918Y2 - - Google Patents

Description

[Detailed description of the invention] This invention suspends granular solids in a tank as a carrier for microbial attachment, and circulates the granular solids in the tank while stirring the gas using an air lift tube installed in the tank. This invention relates to a biological treatment device for fluidized wastewater.

Recently, various biofilm-based sewage treatment systems have been put into practical use, employing tube catalytic oxidation methods, rotating disk methods, granular solid fluidized bed methods, etc., to solve the bulking phenomenon and complexity of maintenance in the activated sludge method. has been done. Among these methods, microorganisms are attached to the surface of granular solids suspended in a tank, and the granular solids are circulated and flowed in the tank while gas agitation is carried out via an air lift pipe installed in the tank, and the solids come into contact with wastewater. The granular solid fluidized bed method, which removes pollutants from wastewater by removing pollutants from wastewater, has a much larger surface area of the granular solids for microorganisms to attach to than other biofilm methods, so it is possible to collect a large amount of microorganisms in the tank. It is attracting attention because it has many advantages, such as the ability to hold solids, and because the granular solids circulate and flow within the tank, problems such as clogging and partial anaerobic formation do not occur.

In this granular solid fluidized bed method, materials such as sand, anthracite, activated carbon, zeolite, and plastic spheres are suitable for attaching microorganisms, and particles with specific gravity and particles suitable for smooth circulation and fluidization within the tank are used. A granular solid with a diameter is used, but sand is usually used due to its price and availability.

Further, the air lift tube has an air introduction tube connected to its lower part, and the granular solids circulate and flow inside and outside the air lift tube due to the air lift action of the air blown into the tube. A part or the entire circumference above the tank in which the air lift pipe is installed is divided into a circulation part and a separation part by a partition wall whose upper end is above the water surface and whose lower end is below the water surface. A portion of the liquid separates granular solids while rising through this separation section, and is taken out from above as effluent water. Furthermore, this effluent is subjected to coagulation and sedimentation as a post-treatment device.
The outflow water is sent to a sand filter, etc., and SS,
After undergoing treatment such as BOD and COD removal, it becomes final treated water.

In conventional fluidized bed biological treatment equipment, granular solids are circulated through the air lift effect of simply blown air, but if the air supply is interrupted due to suspension, power outage, repairs, etc. In this case, the granular solids in the tank will settle on the bottom of the tank, clogging the lower end of the air lift pipe, etc., and it will be extremely difficult to restart the tank by just blowing air. Conventionally, in order to re-fluidize these sedimented particles and facilitate recirculation flow due to the air lift effect, a starting water spray mechanism was installed at the bottom of the tank, and a sufficient amount of starting water was blown in to fluidize the settled particles. A common method has been to fluidize this and then utilize the air lift effect by blowing air to achieve recirculation flow.

However, in conventional equipment, all of these operations were performed manually and by visual observation by the operator, so at what point should air be started after the start-up water is injected, and at what point should the start-up water be blown? In many cases, it is difficult to know whether or not to stop the loading, and problems may occur such as using a large amount of startup water or causing particulate solids to flow out of the tank due to the increased water load on the separation section. The reality was that they were having trouble operating the engine when it started up.

The object of the present invention is to provide a new fluidized bed biological treatment apparatus that eliminates the troubles that tend to occur with conventional apparatuses and allows for simple and reliable restarting.

The present invention has a tank that has a raw water inlet and a treated water outlet and contains granular solids for adhesion of microorganisms.
A circulation section and a separation section are defined by a partition wall whose upper end is above the water surface and whose lower end is separated from the tank bottom, and in the circulation section, the upper end is below the water surface and the lower end is separated from the tank bottom, and air is introduced near the lower end. An air lift pipe with connected pipes is provided, and a starting water spouting mechanism is provided at the bottom of the tank, and an interface detection mechanism is further provided in the circulation section to detect an expansion interface of the granular solid deposited in the tank,
The invention is characterized in that the interface detection mechanism is connected to a control circuit that starts introducing air into the air lift tube in response to a detection signal thereof, and after a certain period of time, stops the jetting of startup water from the jetting mechanism.

An embodiment of the present invention will be described with reference to the drawings. The first illustrated example has a raw water inflow pipe 1 and a treated water outflow pipe 2, and has granular solids 3 for attaching microorganisms.
Inside the tank 4 containing the water, a circulation part 6 and a separation part 7 are separated by a partition wall 5 whose upper end is above the water surface and whose lower end is separated from the tank bottom.
The area is divided into sections. Inside the circulation section 6, there is an air lift pipe 9 whose upper end is below the water surface, whose lower end is separated from the tank bottom, and to which an air introduction pipe 8 is connected near the lower end.
is provided, and the air introduction pipe 8 is connected to air blowing equipment 10 such as a blower.

Further, a pressure chamber 11 is defined at the bottom of the tank 4, and a diff user 12 is installed on the top surface of the pressure chamber 11, and the starting water pressurized into the pressure chamber 11 by a pump 13 is spouted from the diff user 12 into the tank. It has a structure. In the illustrated example, the supernatant water of the separation section 7 is used as the starting water, but the starting water may be collected from the outside. In addition to the type in which a diffuser 12 is installed in the pressure chamber 11, the type that uses a pressure water jet nozzle, and the type that uses a normal watering pipe, etc., have a sufficient amount of water to fluidize the granular solids 3 deposited at the bottom of the tank 4. Any type can be applied as long as it has a structure that allows for the injection of water into the tank.

Furthermore, a tank 4 is provided at an appropriate position within the circulation section 6.
An interface detection mechanism 14 such as an ultrasonic interface meter is provided to detect the expansion interface of the granular solid 3 deposited in the interior of the granular solid. The control circuit 15 controls the air blowing equipment 10 based on the detection signal from the interface detection mechanism 14.
Automatic control is possible to operate the pump 13 and then stop the pump 13 after a certain period of time.

The pump 13 may be stopped, for example, by providing the control circuit 15 with a timer D and a controller C', or by providing a sequence circuit that uses a concentration signal from the interface detection mechanism 14.

Next, to explain its operation, when restarting the operation after stopping due to power outage, repair, etc., the pump 13 pumps starting water from the pressure chamber 11 and the diffuser 12 into the granular solids that had settled at the bottom of the tank. When a sufficient amount of water is ejected to fluidize the granular solid 3, the deposited granular solid 3 gradually expands and the interface of the granular solid 3 rises. When the interface of the granular solid 3 reaches the position of the interface detection mechanism 14, the interface detection signal causes circuits such as the signal converter A, regulator B, and controller C in the control circuit 15 to be operated by a blower in the blower equipment 10, for example. However, by introducing air from the air introduction pipe 8, the liquid containing the granular solids 3 starts to be lifted and circulated through the air lift pipe 9.

After that, the pump 13 is stopped after a certain period of time and the start-up water stops spewing out, but the timer D is controlled by the control circuit 1.
5, the signal from regulator B is also sent to timer D to activate it, and after a preset time, pump 1 is activated via controller C'.
3, and the spout of startup water stops.

In addition, if the pump 13 is stopped without using a timer, based on the signal from the interface detection mechanism 14, as shown in the second diagram, the detected solid concentration is H.
A sequence circuit may be configured in which the blower is operated when the concentration of solids 3 reaches a certain level, and the pump 13 is stopped when the solids concentration falls to a level L at which the granular solids 3 are uniformly circulated in the tank.

Then, following the stop of the pump 13, the raw water is allowed to flow into the tank, and the sequence for starting the flow of this raw water can be arbitrarily adopted.

As described above, according to the present invention, it is possible to easily start up a fluidized bed biological treatment equipment, which conventionally required the operator's skill, and to remove granular solids without requiring an excessive amount of startup water. This has extremely beneficial effects, such as eliminating the problem of leakage and making stable operation possible.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention.
FIG. 2 is a diagram showing temporal fluctuations in the concentration of particulate solids in the detection section. 1... Raw water inflow pipe, 2... Treated water outflow pipe, 3...
... Granular solid, 4 ... Tank, 5 ... Partition wall, 6 ... Circulation section, 7 ... Separation section, 8 ... Air introduction pipe, 9 ... Air lift pipe, 10 ... Air blowing equipment, 11 ... Pressure chamber , 12...Diff user, 13...Pump, 1
4... Interface detection mechanism, 15... Control circuit, D...
timer.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. Circulation in a tank having a raw water inlet and a treated water outlet and containing granular solids for adhesion of microorganisms through a partition whose upper end is above the water surface and whose lower end is separated from the tank bottom. An air lift pipe is provided in the circulation part, the upper end of which is below the water surface, the lower end of which is separated from the tank bottom, and an air introduction pipe connected to the bottom of the tank. Further, an interface detection mechanism is provided in the circulation section to detect an expansion interface of the granular solid deposited in the tank, and the interface detection mechanism starts introducing air into the air lift tube in response to a detection signal from the interface detection mechanism. A fluidized bed biological treatment apparatus, characterized in that it is connected to a control circuit that stops the ejection of startup water from the ejection mechanism after a certain period of time. 2. The fluidized bed biological treatment apparatus according to claim 1, wherein the control circuit is provided with a timer for stopping the start-up water jetting. 3. The fluidized bed biological treatment apparatus according to claim 1, wherein the control circuit includes a sequence circuit for stopping the start-up water spout based on the concentration signal detected by the interface detection mechanism.