JPH0839062A - Immersion type membrane separator - Google Patents

Abstract

PURPOSE:To prevent that activated carbon is discharged along with a cake when the bonded cake is released by washing a membrane element to be discharged out of tank when granular or powdery activated carbon having a bacteria membrane bonded thereto is received in a treatment tank in which the membrane element is immersed and a TOC component in water incapable of being separated by the membrane element is removed by the adsorbing action of activated carbon and the decomposition action of bacteria. CONSTITUTION:A partition wall 11 is vertically provided in a treatment tank 10 to patition the tank into partition chambers A, B communicating with each other at the upper and lower parts thereof and a membrane element 14 is immersed in the partition chamber A, and the opening 17 of a drain means is provided to the partition chamber A under the membrane element at the position above the lower end of the partition wall.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention immerses a membrane element in a liquid in a treatment tank, draws the membrane element with a suction pump and a head difference based on the depth of the water soaked, and performs membrane filtration with low energy. The present invention relates to an immersion type membrane separation device that obtains permeated water.

[0002]

2. Description of the Related Art In various industrial fields, the use of an immersion type membrane separation device is becoming popular in order to obtain permeated water that is sterilized and sterilized from high turbidity raw water. However, in addition to sterilization and sterilization, TOC components such as organic substances such as humic acid and fulvic acid require a driving force of 1 kgf / cm ² or more, and the immersion type membrane separation device requires a driving force. Since it is insufficient, in the liquid of the treatment tank in which the membrane element is immersed, the granular or powdered activated carbon having a microbial membrane adhered to its surface is turbid and flowed,
The TOC component is removed not by the membrane filtration of the membrane element, but by the action of adsorbing activated carbon having a large surface area and the action of degrading microorganisms.

[0003]

If the membrane filtration is continuously carried out, the cake adheres to the surface of the membrane and the filtration efficiency is lowered.
For this reason, it is necessary to wash the cake periodically to remove the cake adhering to the membrane and drain it to the outside, but the activated carbon is also discharged together with the drainage. Therefore, it is necessary to replenish the activated carbon when the membrane filtration is restarted. Moreover, it is troublesome to collect the activated carbon discharged together with the concentrated water.

[0004]

In view of the above, the present invention is designed so that the separated cake can be discharged without discharging activated carbon during cleaning, and a dividing wall is erected in the liquid in the processing tank. In the submerged membrane separation device in which the partition wall divides the tank into upper and lower communicating compartments, and a membrane element is immersed in the compartment, the compartment is under the membrane element, and The drainage means has an opening at a position above the lower end of the partition wall.

[0005]

EXAMPLES In each of the illustrated examples, 10 is a processing tank,
A partition wall 11 is erected in the tank with its lower end separated from the tank bottom 10 'and its upper end positioned below the liquid surface. The partition wall divides the inside of the processing tank into two partition chambers A and B that communicate with each other above and below the partition wall. Of course, it may be divided into two or more rooms.

In the embodiment shown in FIG. 1, the partition wall 11 is plate-shaped and is erected in the processing tank while being supported in a submerged state. Further, the bottom of the division room B is inclined toward the division room A. Figure 2
In this embodiment, a partition wall 12 is constructed integrally with the treatment tank as a wall that stands from the bottom of the treatment tank to the upper surface of the treatment tank. The partition wall has an upper part below the liquid level and a lower part close to the bottom both chambers A, A communication port 13 for communicating B is opened. Therefore, in this embodiment, the upper communication port 13 and the lower communication port 1 of the partition wall 12 are
The area between 3 and 3 becomes the partition wall 11.

Inside one of the compartments A, the upper end is located below the upper end of the partition wall 11 and the lower end is located above the lower end of the partition wall, and the ultrafiltration membrane and microfiltration are used. A membrane element 14 composed of a separation membrane such as a membrane is immersed. Of course, the membrane element may be immersed in each of the compartments A and B. In addition, when it is divided into a plurality of chambers, it may be immersed in all the chambers or every other chamber. An air diffuser 16 from a blower 15 and a drain pipe 17 are provided in the compartment below the membrane element and above the lower end of the compartment wall. Raw water is supplied to the other compartment B by a supply pipe 18. In addition, granular or powdered activated carbon 19 having a microbial membrane attached to the surface is put in the water in both compartments. The amount of the activated carbon is set such that the upper surface thereof is lower than the opening of the drain pipe 17 even if the activated carbon is completely settled. Further, in the case of this embodiment, the air diffuser 16 is provided above the drain pipe 17, but the air diffuser 16 may be provided below the drain pipe 17. In this case, even if all of the activated carbon settles, the upper surface of the activated carbon is set to a position lower than the air diffusing pipe 16.

In order to perform membrane filtration, the raw water is supplied through the supply pipe 18 and the inside of the treatment tank is kept full of water.
The suction pump 21 to which the water suction pipe 20 is connected to the next side is operated, and the blower 15 of the air diffuser 16 is operated to operate the drain pipe 1
Keep valve 7 closed. As a result, oxygen is replenished in the water through the air diffuser 16, the microorganisms attached to the activated carbon 19 maintain the activity and decompose the TOC component in the water, and at the same time the activated carbon is converted to TOC.
Adsorb components. These air bubbles lift the liquid in chamber A,
A circulating flow is generated in the tank by passing over the upper end of the partition wall into the chamber B and dipping the liquid in the chamber B under the lower end of the partition wall into the chamber A, and the activated carbon flows along with the circulating flow. At the same time, the air bubbles scrub the primary surface of the membrane element. Thus, the suction pump 21 drains the permeated water that has permeated from the primary side to the secondary side of the membrane element. This permeated water is sterilized and turbid, and contains no TOC component.

If the membrane filtration operation is performed for several days or months, washing and draining are performed once or more frequently. For this purpose, first, the valve of the raw water supply pipe is closed, the suction pump and the blower are stopped, and the drain pipe 17 is opened to drain water. When the water level in the tank drops slightly from the upper end of the partition wall 11 to W ₁ and the activated carbon is sedimentable, if it settles to the bottom of the tank, the blower 15 is operated while continuing draining, and bubbles are generated from the air diffuser 16. Is ejected to perform a scrubbing process, and the cake adhering to the surface of the film is separated by vibration. If necessary, permeated water or cleaning water containing a chemical solution may be gently supplied to the cleaning pipe 22 connected to the secondary side of the membrane element at this time to perform backwashing. The cake separated from the film is discharged from the drain pipe 17 to the outside of the tank. In the scrubbing process, the water level in the tank is the partition plate 1.
Since the above-mentioned airlift circulation flow due to air bubbles from the diffuser pipe does not occur, the activated carbon is not discharged from the drain pipe because it is performed after the settling activated carbon has settled down from the upper end to the bottom of the tank. Further, even if the activated carbon floats, the air lift circulation flow does not occur, so the concentration of suspended suspended particles in the compartment A can be minimized, and the discharge of the suspended activated carbon from the drain pipe can be minimized. be able to.

When the water level in the tank drops to W ₂ slightly below the lower end of the membrane element, the valve of the drain pipe 17 is closed and the valve of the supply pipe 18 is opened to perform water filling. The operation of the blower may be continued during this water filling, or the blower may be stopped. When the water level in the tank reaches the full water level W, membrane filtration is restarted.

[0011]

As is apparent from the above, according to the present invention, the membrane element is washed to remove the cake adhering to the surface, and when the separated cake is discharged out of the tank together with water, it is put in the tank. Certain powdered or granular activated carbons are not discharged at the same time. Therefore, when the washing is finished and the membrane filtration is restarted, it is not necessary to replenish the activated carbon, and the membrane filtration can be immediately restarted.
Further, the labor for collecting the activated carbon discharged out of the tank becomes unnecessary.

[Brief description of drawings]

FIG. 1 is a system diagram of a first embodiment of an immersion type membrane separation device of the present invention.

FIG. 2 is a system diagram of a second embodiment of the immersion type membrane separation device of the present invention.

[Explanation of symbols]

 10 Treatment Tank 11 Section Wall 14 Membrane Element 15 Blower 16 Diffuser Pipe (Diffuser Means) 17 Drain Pipe (Drainage Means) 18 Raw Water Supply Pipe 19 Activated Carbon 20 Suction Pipe 21 Suction Pump 22 Cleaning Pipe

Claims (1)

[Claims] 1. An immersion type in which a partition wall is erected in a liquid in a treatment tank, and the partition wall divides the tank into upper and lower communicating compartments, and a membrane element is immersed in the compartment. In the membrane separation device, the submerged membrane separation device is characterized in that an opening of a drainage means is provided in the partition chamber below a membrane element and above the lower end of the partition wall.