JPH11114563A - Water treating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To conveniently clean the face of the membrane of a membrane separator with a liq. chemical without suspending filtration. SOLUTION: The first and second membrane separators 14 and 15 are dipped in an aeration tank 12 and set. Permeated water pipes 21 and 24 communicated with the membrane-permeated water passages of the separators 14 and 15 through solenoid valves 22 and 25 are furnished, liq. chemical injection pipes 29 and 30 communicating with the membrane-permeated water passages of the separators 14 and 15 through solenoid valves 26 and 27 are provided, and the membrane separator to conduct filtration is switched to the membrane separator with the membrane to be cleaned and vice versa by opening or closing the solenoid valves 22, 25, 26 and 27.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a water treatment apparatus such as a septic tank.

[0002]

2. Description of the Related Art In a septic tank shown in FIG. 2, for example, raw water 1 is introduced into a denitrification tank 2 and an activated sludge mixed solution 3 in the denitrification tank 2 is transferred to a nitrification tank 4 while an activated sludge mixture in the nitrification tank 4 is transferred. In a state in which a part of the sludge mixture 5 is returned to the denitrification tank 2, the denitrification treatment is performed in the denitrification tank 2 under anaerobic conditions, and in the nitrification tank 4, the air is diffused by the diffusion device 6 under aerobic conditions. At the same time as the nitrification treatment, the activated sludge mixed liquid 5 in the nitrification tank 4 is filtered by the membrane element 8a of the membrane separation device 8 by a suction filtration method using a suction pump 7 (or a gravity filtration method using a water level difference). The permeated water that has passed through the surface is led out of the nitrification tank 4 through the permeated water outlet pipe 8b. Then, periodically or when necessary, a chemical solution 9 such as sodium hypochlorite solution is injected into the permeated water side of the membrane element 8a to clean the membrane surface of the membrane element 8a.

[0003]

However, in the water treatment apparatus as described above, the filtration process must be stopped for a few hours required for cleaning the chemical solution, and the filtration process is started when the cleaning of the chemical solution is completed. At present, the administrator is bound to perform the operation of performing the operation.

An object of the present invention is to solve the above-mentioned problem, and an object of the present invention is to provide a water treatment apparatus capable of easily cleaning a membrane surface of a membrane separation apparatus with a chemical solution without stopping a filtration process.

[0005]

In order to solve the above-mentioned problems, the water treatment apparatus according to the first aspect of the present invention is provided with a plurality of membrane separation devices immersed and installed in a treatment tank. Opening / closing operation of each valve device by providing a permeated water derivation system communicating with the membrane permeated water flow path via a valve device, and providing a chemical liquid injection system communicating with the membrane permeated water flow channel of each membrane separation device via a valve device. Thus, a membrane separation device that performs a membrane filtration process and a membrane separation device that performs a membrane cleaning process are switched. Here, the membrane separation device means a unit device that can be operated integrally, and also includes a device configured by a plurality of membrane modules.

According to a second aspect of the present invention, in the water treatment apparatus, an electromagnetic valve is disposed as a valve device, a control device electrically connected to each electromagnetic valve is provided, and each electromagnetic valve is controlled to open and close by the control device. The membrane washing step of shutting off the communication of the permeated water derivation system with the membrane permeated water flow path of the membrane separation device and opening the flow path of the drug solution injection system with respect to the membrane permeated water flow channel of the membrane separation device, and injecting the drug solution into each membrane, It is characterized in that it is configured to perform the operations sequentially on the separation device.

According to the first aspect of the present invention, the membrane separating apparatus for performing the membrane filtration step and the membrane separating apparatus for performing the membrane cleaning step can be switched by opening and closing the respective valve devices. While the separation apparatus performs the membrane washing step, the other membrane separation apparatuses can perform the membrane filtration step, and the membrane separation apparatus can be washed with a chemical solution without stopping the filtration process.

According to the second aspect of the present invention, the opening and closing of each solenoid valve is controlled by the control device, and the plurality of membrane separation devices are automatically and sequentially cleaned with the chemical solution.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, an activated sludge mixture 13 is immersed in an aeration tank 12 in which a treated water supply pipe 11 is opened, and a first membrane separation device 14 and a second membrane separation device 1 are immersed.
5 are installed.

The first membrane separator 14 and the second membrane separator 15 are respectively arranged with membrane elements 14a and 15a, and water collecting pipes 14b and 15b communicating with the membrane permeated water flow paths of the respective membrane elements 14a and 15a. have.
Below the first membrane separator 14 and the second membrane separator 15 are provided diffusers 19 and 20 which communicate with a blower 18 via solenoid valves 16 and 17, respectively.

A first permeated water outlet pipe 21 communicates with the water collecting pipe 14b of the first membrane separation device 14, and this first permeated water outlet pipe 21 is provided with a solenoid valve 22 and a suction pump 23, and is connected to a tank. Open outside. A second permeated water outlet pipe 24 communicates with the water collection pipe 15b of the second membrane separation device 15, and the second permeated water outlet pipe 24 is provided with an electromagnetic valve 25 and is connected to the first permeated water outlet pipe 21. It communicates with a position between the solenoid valve 22 and the suction pump 23.

The first permeated water outlet pipe 21 at a position upstream of the solenoid valve 22 and the second permeated water outlet pipe 24 at a position upstream of the solenoid valve 25 are connected to the chemical via electromagnetic valves 26 and 27, respectively. Chemical liquid injection pipes 29 and 30 connected to the tank 28 communicate with each other.

The solenoid valves 22, 25, 26 and 27 are electrically connected to a control device 31 for controlling the opening and closing of the solenoid valves 22, 25, 26 and 27 as described later. The operation of the above configuration will be described.

The water to be treated is supplied to the inside of an aeration tank 12 through a water supply pipe 11 to be mixed with the activated sludge mixture 13, and pollutants in the water to be treated are diffused by diffusers 19, 20.
It is oxidatively decomposed by the action of activated sludge under more aerobically aerobic conditions.

At this time, the solenoid valves 25 and 26 are closed and the solenoid valves 22 and 27 are opened by the control device 31, so that the first valve communicating with the water collecting pipe 14 b of the first membrane separation device 14 is formed. The permeated water outlet pipe 21 is opened and the first chemical liquid injection pipe 29 is closed, and the suction pump 23 applies a suction pressure acting on each membrane element 14a through the first permeated water outlet pipe 21 so that the first chemical liquid injection pipe 29 is closed on the membrane surface. Filtration is performed, and the permeated water that has passed through the membrane surface and flowed into the permeated water flow path is led out of the tank through the water collecting pipe 14b and the first permeated water outlet pipe 21.

The water collecting pipe 15b of the second membrane separation device 15
The second permeated water outlet pipe 24 communicating with the second liquid injection pipe 30 is closed and the second chemical liquid injection pipe 30 is in an open state, and the liquid chemical such as sodium hypochlorite in the chemical liquid tank 28 is filled with the second liquid injection pipe 30. , The second permeated water outlet pipe 24 and the water collecting pipe 15b are injected into the permeated water flow path of the membrane element 15a to permeate the membrane surface into the activated sludge mixture 13 side, and the membrane surface is washed.
Even after the chemical solution injection is completed, the state where the second chemical solution injection pipe 30 is opened and the second permeated water outlet pipe 24 is closed is maintained, and when the chemical solution is sodium hypochlorite, most of the chemical vaporizes. .

At the time of the regular maintenance, the electromagnetic valves 25 and 26 are opened and the electromagnetic valves 22 and 27 are closed by the control device 31, whereby the water collecting pipe 15b of the second membrane separation device 15 is connected to the water collecting pipe 15b. The connected second permeated water outlet pipe 24 is opened, and the second chemical liquid injection pipe 30 is closed, so that filtration is performed on the membrane surface of the membrane element 15a, and the permeated water is drawn out of the tank. , First
The first permeated water outlet pipe 21 communicating with the water collection pipe 14b of the membrane separation device 14 is closed, and the first chemical liquid injection pipe 29 is opened, and the membrane element 14a is washed with the chemical liquid.

In this way, the second membrane separator 15 can be washed while the first membrane separator 14 filters the membrane, and when the first membrane separator 14 becomes contaminated, the first membrane separator 15 is automatically cleaned. Since the operation is switched to the operation of membrane filtration by the second membrane separation device 15 while the device 14 is being washed with a membrane,
Each membrane separation device can be washed with a chemical solution without stopping the filtration process, and the permeation flux can be maintained.

In the above description, the aeration tank 12 for performing the activated sludge treatment has been described as an example.
The present invention can be applied to a nitrification tank provided together with the above-described denitrification tank or a mere solid-liquid separation tank. The first and second membrane separation devices 14 and 15 may be of any type as long as they are of the immersion type (external pressure type), such as a tubular or flat plate having various membranes such as a ceramic membrane and an organic membrane. Various shapes of membrane elements are possible. First and second permeated water outlet pipes 21 and
4 may be provided independently without being combined.
25 and the solenoid valves 26 and 27 may be replaced by switching valves.

In the above, the control device 31 is provided to automatically switch the operation. However, it is not necessary to switch to the membrane filtration operation at the end of the cleaning of the chemical solution as in the prior art. The work is easy, and in that case, each solenoid valve may be replaced with a normal on-off valve. The two diffusers may be operated at all times, or only the diffuser below the membrane separation device that performs the filtration may be operated,
In that case, it is convenient to link the respective membrane separation devices (that is, solenoid valves) by the control device 31.

[0021]

As described above, according to the present invention, it is possible to switch between a membrane separation device for performing a membrane filtration process and a membrane separation device for performing a membrane cleaning process by opening and closing a valve device. The membrane separation device can be washed with a chemical solution without stopping the filtration process, and management is easy.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a schematic overall configuration of an aeration tank as a water treatment apparatus according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing a schematic overall configuration of a septic tank as a conventional water treatment apparatus.

[Explanation of symbols]

 12 Aeration tank 14 First membrane separator 15 Second membrane separator 21 First permeate outlet pipe 24 Second permeate outlet pipe 22, 25 Solenoid valve 26, 27 Solenoid valve 28 Chemical tank 29 First chemical inlet 30 2 Chemical injection tube 31 Controller

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Koichi Okada 1-1-1 Hama, Amagasaki-shi, Hyogo Inside Kubota Research Institute of Technology (72) Inventor Kazuyuki Honda 2 Takamatsu, Kosai-cho, Koga-gun, Shiga Prefecture 1 Kubota Shiga Plant

Claims (2)

[Claims] 1. A plurality of membrane separation devices are immersed and installed in a treatment tank, and a permeated water discharge system is provided to communicate with a membrane permeated water flow path of each membrane separation device via a valve device. A chemical liquid injection system that communicates with the membrane permeated water flow path via a valve device is provided, and the opening and closing operation of each valve device switches between a membrane separation device that performs a membrane filtration process and a membrane separation device that performs a membrane cleaning process. A water treatment apparatus characterized by the above-mentioned. 2. An electromagnetic valve is disposed as a valve device, a control device electrically connected to each electromagnetic valve is provided, and each electromagnetic valve is controlled to be opened and closed by the control device. The membrane washing step of shutting off the communication of the permeated water discharge system to the membrane separation apparatus and opening the flow path of the chemical liquid injection system to the membrane permeated water flow path of the membrane separation apparatus and injecting the chemical liquid is sequentially performed for each membrane separation apparatus. The water treatment apparatus according to claim 1, wherein the water treatment apparatus is configured as described above.