JPH06181B2 - ▲ Ro ▼ Backwash method of excess equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a perfusator, and more particularly to a backwashing method which is effective when a hollow fiber membrane has a poor air permeability.

[Conventional technology and its problems]

A backwashing method which has been conventionally performed in a filtration apparatus using a hollow fiber membrane will be described with reference to FIG.

The liquid to be treated in the liquid to be treated tank 1 is supplied from the distribution mechanism 6 to the excess device 4 via the liquid supply line 8 while the flow rate is adjusted by the pump 2 via the flow rate adjusting valve 3, and the supplied liquid to be treated is After flowing upward through the filter and passing through the media 5, the processing liquid (liquid) is discharged from the processing liquid line 9 through the dome above the tube sheet. During the overtreatment of the water to be treated, the differential pressure (over resistance) is measured by the differential pressure detector DP, and when the differential pressure exceeds a certain value, the supply of the liquid to be treated is stopped and the treatment liquid line After closing 9, the backwash is performed.

When backwashing is performed by using air, the dome liquid on the upper part of the apparatus 4 is discharged from the dome drain line 14 and then pressurized from the pressurized air line 12 to pressurize the inclusion liquid to the backwash liquid discharge line 16. After discharging all at once, the liquid filling line 11
Liquid is filled until it reaches the tube sheet, and then the scrubbing air line 13 passes through the liquid supply line 8 and the distribution mechanism 6
Air is introduced into the excess device 4, the excess media is scrubbed with air, and then drained from the backwash liquid drain line 16,
Then, it is introduced from the liquid filling lines 10 and 11 to fill the liquid. If the hollow fiber membrane has good air permeability, air scrubbing may be omitted.

On the other hand, when backwashing is performed using only the liquid (when the air permeability of the hollow fiber membrane is poor), the backwashing liquid is press-fitted from the backwashing liquid line 10 to almost the lower part of the tube plate of the apparatus 4. The liquid up to is drained all at once from the backwash liquid drain line 16, then the opening line 15 is opened at the time of scrubbing, and the air is introduced from the scrubbing air line 13 through the liquid feed line 8 and the distribution mechanism 6 into the excess device. After air scrubbing the excess medium 5, liquid is drained from the backwash drain line 16, and then liquid is introduced from the liquid fill lines 10 and 11 to fill the liquid.

In both cases of the former and latter methods in the above backwashing, the amount of waste liquid generated during the backwashing process is close to twice the amount of the liquid contained in the excess device 4, which is not preferable in terms of waste liquid reduction measures.

[Structure of Invention]

The present invention relates to a method for backwashing an excess device, (a) opening the pressurized air line and performing the dome drain of the excess device through the dome drain line, and (b) then closing the dome drain line and applying Air is supplied from the compressed air line to pressurize the inside of the dome, and after the air inside the dome reaches the specified pressure, the pressurized air line is closed, and (c) the backwash liquid drain line is opened and the discharged liquid is piped. Drain the liquid until it reaches the bottom of the plate and the backwash liquid drain line runs out, or open the backwash liquid drain line at the same time and immediately close the backwash liquid drain line and drain. After the liquid reaches the bottom of the tube plate and drains the backwash liquid drain line until the liquid runs out, (d) Open the scrubbing air line and supply air from the distribution mechanism via the liquid supply line. When scrubbing, exhaust air from the open line while The air is scrubbed for a predetermined time, and then (e) the scrubbing air line is closed, the drain line is opened, and after draining all the backwash liquid, the drain line and the scrubbing open line are closed. This is a backwashing method for the overwashing device, and since the liquid contained in the overwashing device 4 is not discharged before the air scrubbing, the amount of waste liquid generated during the backwashing process is included in the overwashing device 4. Only the amount of liquid is used, and the amount of waste liquid is about half that of the conventional method, which is advantageous in terms of waste liquid countermeasures.

After the backwashing is completed, the liquid is introduced from the liquid filling line 11 into the excess device 4 and reaches the lower tube sheet supporting the excess medium 5, and when the solution begins to come out from the tube sheet air vent line 15, the tube sheet is released. The air vent line 15 and the liquid filling line 11 are closed. Then, the pent 17 and the liquid filling line 10 are opened, the liquid is introduced from the liquid filling line 10 to the upper part of the apparatus, and when the liquid begins to come out from the vent 17, the vent 17 and the liquid filling line 10 are closed, and the treatment liquid After opening the line 9, the liquid to be treated is introduced from the liquid to be treated tank and the treatment of the liquid to be treated is restarted.

By the way, in the above step (c), if the diameter of the backwash liquid drain line 15 is about the same as the diameter of the backwash liquid drain line 16 and is sufficiently large, Only the liquid should be discharged.

However, when the backwashing liquid drainage line mounting portion in the apparatus needs to be raised as shown in FIG. 1A, or when a hole for leading to the backwashing liquid drainage line 15 is formed in the tube plate portion, In the former case, from the viewpoint of securing an excessive area, in the latter case, if the hole is large, the tube plate becomes thick, and therefore the diameter of the backwash liquid drainage line 15 cannot be increased.
The backwash liquid drainage line 15 generally has a smaller diameter than the backwash liquid drainage line 16. As a result, the pressure loss during backwashing in the backwashing liquid drain line 15 becomes considerably large, and there is a risk that the pressure difference between the excess material surfaces during backwashing may not be sufficient.

In this case, the backwash drainage line 16 is also opened instantaneously, the pressure difference between the material surfaces is secured, the material is shocked, and then closed. Drain.

[Brief description of drawings]

FIG. 1 is a flow chart showing an example of a transit device used in the present invention. 1 ・ ・ Processed liquid tank, 2 ・ ・ Supply pump, 4 ・ ・ Over device, 5 ・ ・ Over media, 6 ・ ・ Distribution mechanism, 7 ・ ・ Backwash receiving tank, 8 ・ ・ Liquid supply line, 9 ・ ・Processing liquid line,
10 ··· Backwashing liquid combined liquid filling line, 11 ··· Liquid filling line, 12 · · Pressurized air line, 13 · · Scrubbing air line, 14 · · Dome drain line, 15 · · Tube plate air vent line Open line for scrubbing and backwash liquid drainage line, 16 ・ ・ Backwash liquid drainage line and drain line, 17 ・ ・ Vent

Claims (1)

[Claims] 1. A method of backwashing an over-apparatus, comprising: (a) opening a pressurized air line (12) and performing a dome drain of the over-apparatus 4 via a dome drain line (14); Close the dome drain line (14), supply air from the pressurized air line (12) to pressurize the dome, and close the pressurized air line (12) after the air in the dome reaches a predetermined pressure. , (C) Open the backwash liquid drain line (15) and discharge the liquid until the drain reaches the bottom of the tube plate and the backwash liquid drain line (15) runs out, or The washing liquid drain lines 15 and 16 are simultaneously opened, the backwash liquid drain line (16) is instantly closed, and the drainage liquid reaches the lower part of the tube plate and the backwash liquid drainage line (15) runs out of liquid. After the liquid has been discharged until (4), the air line (13) for scrubbing is opened, and the distribution mechanism (8) is opened via the liquid supply line (8). While supplying air and exhausting air from the open line (15) during scrubbing, air scrubbing the excess media in the device (4) for a predetermined time, and then (e) closing the scrubbing air line (13), A method for backwashing an over-apparatus characterized in that the drain line (16) is opened, all the backwash liquid is discharged, and then the drain line (16) and the scrubbing open line (15) are closed.