JP3333086B2 - Water treatment equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water treatment apparatus having a plurality of membrane separation devices installed inside a treatment tank.

[0002]

2. Description of the Related Art Conventionally, as a water treatment apparatus for performing human waste treatment or merger treatment, there is known a water treatment apparatus in which a membrane separation device is installed inside a treatment tank.

As shown in FIG. 2, in a membrane separation apparatus 1, flat filtration membrane cartridges 3 are arranged at regular intervals inside a box-frame-shaped membrane case 2 having an open top and bottom, and the top and bottom are also opened. Inside the box frame-shaped diffuser case 4, a blower 5
An air diffuser 6 communicating with an air supply source such as the above is provided, and the membrane case 2 and the air diffuser case 4 are arranged above and below each other.

[0004] The filtration membrane cartridge 3 has a filtration membrane 8 disposed on both surfaces of a filtration plate 7 and a membrane permeated liquid flow path formed between the filtration plates 7 and between the filtration plates 7 or inside the filtration plate 7. (Not shown), a membrane permeate outlet 9 communicating with the membrane permeate outlet 9 is formed in the filter plate 7. The collecting pipe 11 and the membrane permeated liquid outlet pipe 12 communicate with each other via the permeated liquid extraction tube 10.

In such a configuration, when filtering a liquid to be treated such as an activated sludge mixed liquid in the treatment tank, gravity filtration is performed using the head of the liquid to be treated in the tank as a driving force, or suction means is used. By performing suction filtration using a suction pressure applied through the membrane permeate outlet pipe 12 as a driving force (not shown), suspended substances such as activated sludge contained in the liquid to be treated are captured by the filtration membrane 8, The membrane permeated liquid that has passed through the filtration membrane 8 and flowed into the permeated liquid flow path is taken out of the treatment tank through the permeated liquid extraction tube 10, the collecting pipe 11, and the permeated liquid outlet pipe 12.

At this time, the air is diffused by the blower 5 through the air diffusing hole 6a of the air diffusing device 6, and the air bubbles of the diffused air and the ascending water flow generated by the air are caused to flow into the gap between the filtration membrane cartridges 3. In addition to supplying air to the liquid to be treated, a circulating water flow circulating inside and outside the membrane case 2 and the air diffuser case 4 is formed to reduce concentration polarization on the membrane surface, and to reduce the entire membrane surface of the filtration membrane cartridge 3. Wash it evenly.

[0007]

However, in the above-described membrane separation apparatus, a cake layer is gradually formed on the membrane surface of the filtration membrane cartridge 3 even though the membrane is washed by bubbles or a rising water flow. Ability decreases.

In such a case, in the gravity filtration method, the cake layer does not become strong, so that the cleaning is easy. On the other hand, if the filtration operation is not stopped, it is impossible to increase the head more than a predetermined value. May not be processed.

In the suction filtration method, a predetermined amount of treatment can be ensured by increasing the suction pressure, but cleaning is difficult because the cake layer becomes strong. Also, power such as a suction pump is required.

An object of the present invention is to solve the above-mentioned problem, and an object of the present invention is to secure a predetermined throughput while taking advantage of gravity filtration.

[0011]

Means for Solving the Problems To solve the above problems, a water treatment apparatus according to claim 1 of the present invention is a water treatment apparatus in which a plurality of membrane separation devices are installed inside a treatment tank. The membrane separation device is provided with a membrane permeate outlet pipe that communicates with the membrane permeate flow path of each of the arranged filtration membrane cartridges, and each membrane permeate outlet pipe is located below the liquid level in the tank under atmospheric pressure outside the tank. And a suction pipe communicating with the suction means through a valve device.

According to a second aspect of the present invention, each of the membrane permeate outlet pipes is further connected to a backwash liquid supply pipe for supplying a backwash liquid via a valve device. When the above-mentioned water treatment apparatus is operated, usually, in a state where each membrane permeated liquid outlet pipe is connected to the discharge pipe, the liquid to be treated in the tank is gravity-filtered by each membrane separation apparatus, and any one of the membranes is filtered. When clogging occurs in the separation device, one of the following methods a) to d) depends on whether or not the processing amount can be reduced: a) Derivation of the membrane permeate from the clogged membrane separation device While the pipe communicates with the suction pipe and the membrane permeate outlet pipe of the other membrane separation device communicates with the discharge pipe, the liquid to be treated in the tank is suction-filtered by the clogged membrane separation apparatus, Gravity filtration with a membrane separator, or b) The membrane permeate outlet pipe of the clogged membrane separator is connected to the backwash liquid supply pipe, and the membrane permeate outlet pipe of the other membrane separator is connected to the discharge pipe. As a communication state, a backwash liquid such as a chemical solution is supplied through the backwash liquid supply pipe. The liquid to be treated in the tank is gravity-filtered by another membrane separation device while backwashing the clogged membrane separation device by clogging, or c) a membrane permeated liquid outlet pipe of the clogged membrane separation device. Is connected to the backwash liquid supply pipe and the membrane permeate outlet pipe of the other membrane separation device is connected to the suction pipe, and clogging is caused by injecting a backwash liquid such as a chemical solution through the backwash liquid supply pipe. The liquid to be treated in the tank is suction-filtered by another membrane separation device while backwashing the membrane separation device, or d) b) is performed after a) described above, and thereafter, the operation returns to the normal operation.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. The water treatment apparatus 13 shown in FIG. 1 is provided with a membrane separation apparatus having substantially the same configuration as the conventional membrane separation apparatus described with reference to FIG. The detailed description is omitted by attaching the reference numerals.

That is, the water treatment device 13 is
A plurality of membrane separation devices 1 are installed in the inside, and each membrane separation device 1 includes a membrane permeated liquid outlet pipe 12 that communicates with the membrane permeated liquid flow path of each of the arranged filtration membrane cartridges 3.

Each membrane permeated liquid outlet pipe 12 is located outside the tank.
It communicates with a discharge pipe 16 that is opened under atmospheric pressure, a suction pipe 17 to which a suction pressure is applied, and a backwash liquid supply pipe 18,
The discharge pipe 16, the suction pipe 17, and the backwash liquid supply pipe 18 are provided with on-off valves 19, 20, and 21, respectively.

The discharge pipe 16 is opened above the water collecting trough 22 provided along the side wall near the bottom of the processing tank 14 and below the level of the liquid 15 to be processed in the tank. The collecting trough 22 is guided to a disinfection tank (not shown) or the like.

The suction pipe 17 communicates with a closed type water collecting pipe 23 provided along the side wall at a position near the bottom of the processing tank 14. The water collecting pipe 23 is provided with a suction pump 24 and is connected to a disinfecting tank ( (Not shown).

The backwash liquid supply pipe 18 is provided vertically and has an upper end open to the atmospheric pressure, and is a backwash liquid injecting means (not shown) for injecting a backwash liquid such as backwash water or a chemical solution. ) Can be connected, and the backwash liquid is sent to the membrane separation device 1 by a head difference or forcibly.

Hereinafter, a method of operating the water treatment apparatus 13 will be described. (1) Normally, each on-off valve 19, 21 is opened and each on-off valve 20 is closed, so that each membrane permeated liquid outlet pipe 12 is opened.
Are subjected to gravity filtration of the liquid to be treated 15 in the tank by each of the membrane separation devices 1 in a state where they are in communication with the discharge pipes 16 respectively.

(2) For example, when clogging occurs in the rightmost membrane separation device 1 (hereinafter, this membrane separation device and corresponding members are denoted by the letter A), the processing amount is reduced. (A) By opening the on-off valve 20A and closing the on-off valves 19A and 21A, the clogged membrane permeated liquid outlet pipe 12A of the clogged membrane separation device 1A communicates with the suction pipe 17A. And other membrane separation devices 1
The membrane permeated liquid outlet pipe 12 communicates with the discharge pipe 16 so that the liquid to be treated 15 in the tank is clogged with the clogged membrane separation apparatus 1.
By performing gravity filtration with another membrane separation device 1 while performing suction filtration with A, or (b) by opening the on-off valve 21A and closing the on-off valves 19A and 20A,
Backwashing is performed in a state where the membrane permeated liquid outlet pipe 12A of the clogged membrane separation apparatus 1A communicates with the backwash liquid supply pipe 18A, and the membrane permeated liquid outlet pipe 12 of the other membrane separation apparatus 1 communicates with the discharge pipe 16. The clogged membrane separation device 1A is backwashed by injecting a backwash solution such as a chemical solution through the liquid supply pipe 18A, and the liquid 1 to be treated in the tank is washed by another membrane separation device 1.
5 through gravity filtration or (c) on-off valve 21A
Is opened, and the on-off valves 19A and 20A are closed, so that the membrane permeated liquid outlet pipe 12 of the clogged membrane separator 1A is opened.
A is connected to the backwash liquid supply pipe 18A, and the on-off valve 20 is opened and the on-off valves 19 and 21 are closed, so that the membrane permeated liquid outlet pipe 12 of the other membrane separation device 1 is connected to the suction pipe. 17, while the backwashing of the clogged membrane separation apparatus 1A is performed by injecting a backwashing liquid such as a chemical solution through a backwashing liquid supply pipe 18A, the processing in the tank by the other membrane separation apparatus 1 is performed. The liquid 15 is subjected to suction filtration, or (d) the step (b) is performed after the step (a), and then the operation returns to the normal operation of the step (1).

According to the above-mentioned water treatment apparatus 13 and its operation method, since gravity filtration is usually performed, clogging hardly occurs and a power source such as a suction pump is not required. Emergency operation can be switched for each membrane separation device 1.

At this time, the membrane separation device 1 clogged by gravity filtration can be suction-filtered for a short period of time, and when suction filtration is performed while backwashing, even a small number of membrane separation devices 1 can be used. Since almost the same amount of liquid to be treated can be filtered as in the normal operation, clogging can be eliminated without stopping the processing, and a predetermined amount of processing can be performed. Further, since only the required number of the membrane separation devices 1 need be switched to the suction filtration, the operation for accelerating the clogging can be minimized.

The degree of clogging can be checked by measuring the flow rate at the time of gravity filtration for each membrane separation device 1.
When clogging does not occur, switching to suction filtration can cope with an emergency in which a predetermined amount or more of the liquid to be treated flows.

Further, the backwash liquid supply pipe 18 as described above
It is also possible to inject a backwash liquid such as a chemical solution through the discharge pipe 16 or the suction pipe 17 without providing the above.

[0025]

As described above, according to the present invention, clogging can normally be prevented by performing treatment by gravity filtration, and when clogging occurs, gravity filtration and suction filtration or gravity filtration can be performed. By switching to an emergency operation in which the backwashing or the suction filtration and the backwashing are performed in parallel, the clogging can be eliminated without stopping the processing, and the processing amount can be secured.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an overall configuration of a water treatment apparatus according to an embodiment of the present invention.

FIG. 2 is a partially broken perspective view showing an entire configuration of a conventional immersion type membrane separation device installed inside a treatment tank in the water treatment device shown in FIG.

[Explanation of symbols]

 1 Membrane Separation Device 3 Filtration Membrane Cartridge 12 Membrane Permeate Outlet Tube 13 Water Treatment Device 14 Treatment Tank 16 Release Tube 17 Suction Tube 18 Backwash Water Supply Tube 24 Suction Pump

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masaharu Nishi 2-47, Shikitsuhigashi, 1-chome, Naniwa-ku, Osaka-shi, Osaka Examiner Tadahiro Manada, Kubota Co., Ltd. (56) References JP-A-6-23245 (JP) , A) JP-A-8-131785 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C02F 1/44 B01D 63/08 B01D 65/02

Claims (2)

(57) [Claims] In a water treatment apparatus having a plurality of membrane separation devices installed inside a treatment tank, each of the membrane separation devices has a membrane permeate outlet pipe communicating with a membrane permeate flow path of each of the arranged filtration membrane cartridges. Each membrane permeated liquid outlet pipe communicates via a valve device with a discharge pipe that opens to the atmosphere outside the tank at a position below the liquid level in the tank, and a suction pipe that communicates with the suction means. Characterized water treatment equipment. 2. The water treatment apparatus according to claim 1, wherein each membrane permeate outlet pipe is further connected to a backwash liquid supply pipe for supplying a backwash liquid via a valve device.