JPH0657304B2 - Membrane modular water treatment system - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a water treatment device using a membrane such as a reverse osmosis membrane, an ultrafiltration membrane and a microfiltration membrane.

[Prior art]

As is well known, when seawater is desalted or hard water is softened using a reverse or osmosis membrane, contaminants are deposited on the surface of the membrane due to hardness in the raw water or bacteria, resulting in deterioration of water quality or production of water. It is unavoidable that the decline of In particular, since the reverse osmosis membrane is placed under high pressure, the membrane is compacted in proportion to the operating time, and this also leads to a decrease in the amount of water produced.

[Problems to be Solved by the Invention]

Therefore, the present invention provides a water treatment device capable of automatically and effectively performing a membrane cleaning operation at a predetermined time so as to prevent contamination and consolidation of the membrane.

[Means for Solving the Problems]

The present invention has been made to achieve the above object, and specifically, a flushing valve for discharging concentrated water at a large flow rate is arranged in a concentrated water line of a membrane module structure. The raw water line communicating with the membrane module structure is provided with a bypass line for injecting a cleaning chemical, and a three-way valve for switching between the bypass line and the main line is attached to the raw water line. It is equipped with a set of pressure gauges for detecting the pressure difference on the downstream side, and a mechanical or electric calendar timer that operates each of the above valves at any time on any day for a desired time. is there.

[Action]

In the water treatment apparatus of the present invention, after the apparatus is stopped, the concentrated water is discharged from the membrane module constituent for a predetermined time, then the chemical is injected into the raw water line of the membrane module constituent, and this state is maintained for the predetermined time. After that, a water washing step, that is, a step of removing deposits on the film is started. At that time, the above-mentioned chemical injection step is repeated according to the operation period or the nature of the raw water, and then new raw water is introduced into the membrane module structure to take out normal treated water from the treated water line. To do so. Further, whether or not the membrane surface can be sufficiently cleaned by the above operation and the state of deterioration of the membrane itself are determined by a pair of pressure gauges installed on the upstream side and the downstream side of the membrane module structure. This is done using the differential pressure of.

【Example】

An embodiment of the membrane module type water treatment device according to the present invention will be described below with reference to FIG. In the drawing, one end side of the membrane module structure (1) is
Concentrated water line (2) is connected and this concentrated water line
(2) An orifice (14) is connected in the middle of the line. In addition, the concentrate line (2) has the orifice (14)
A bypass line (2 ') is connected across the line, and a motor-operated flushing valve (3) is connected in the middle of the bypass line (2'). Therefore, the orifice (14) and the flushing valve (3) are connected in parallel. Also, a treated water line (13) is connected to the same side as the concentrated water line (2) of the membrane module structure (1), and the side opposite to the concentrated water line (2) of the membrane module structure (1). A raw water line (4) is connected to this. A three-way valve (5) is provided in the middle of the raw water line (4) .In addition, a chemical feeder (6) such as an ejector and a low flow orifice (19) are sandwiched by the three-way valve (5). A bypass line for drug injection (hereinafter, abbreviated as "medicine injection bypass line") (7) is connected. A chemical injection line (8) extending from the chemical liquid tank (9) is further connected to the chemical feeder (6). A water supply pump (10) is inserted into the raw water line (4), and a cartridge filter (11) is provided on the upstream side thereof. The extended end of the filter (11) communicates with the raw water tank (12). Further, one set of pressure gauges (P1) and (P2) is installed on the upstream side (raw water line inlet) and the downstream side (concentrated water outlet) of the membrane module structure (1). The pressure gauges (P1) and (P2) are for detecting the pressure difference between the pressure gauges (P1) and (P2) to detect the flow resistance of the membrane module structure (1). In addition, this membrane modular water treatment system
When (0) is activated, the raw water in the raw water tank (12) reaches the three-way valve (5) through the cartridge filter (11) and always flows as it is to the membrane module structure (1) where it is treated by the membrane. After receiving the water, it flows into the treated water line (13),
By switching the port of the three-way valve (5), raw water flows from the raw water line (4) to the chemical injection bypass line (7), and then enters the membrane module structure (1). When (3) is opened, it flows out from the concentrated water line (2) at a low pressure with an increased flow rate. A calendar timer (20) for operating the three-way valve (5) and the flushing valve (3) continuously during this operation is provided. In addition, this calendar timer (2
0) and the above three-way valve (5) and flushing valve (3)
These two elements are in a state of being electrically connected by the signal lines (21) and (22). In the embodiment shown in FIG. 1, the concentrated water return path (1) is branched from the concentrated water side bypass line (2 ') and merges between the water supply pump (10) and the cartridge filter (11).
5) is connected, and the feed water pump (10) is connected in parallel with the pressure regulating circuit (16) of the feed water pump. Furthermore, flow indicators (17a), (17b), (17b), (17b), (17b), (17b), (17b), (17b), (17a), (17b), 17c) is inserted. In the water treatment device with such a configuration, the raw water line
Ions are removed from the raw water supplied from (4) via the membrane module structure (1), and this permeated water is treated water (1).
By supplying concentrated water from the concentrated water line (2) to the outside of the system while supplying it to each use point from (3) (a certain amount is taken into the raw water line (4) from the return path (15) above). , The desired water treatment operation is performed. During flushing, that is, when cleaning the membrane by flowing a large amount of raw water, the calendar timer (20) opens the flushing valve (3) as described above, and the raw water is supplied to the membrane at a low pressure and a large flow rate. By acting, the deposits on the surface of the film are taken into the flow to remove dirt, and at the same time,
It is possible to eliminate the consolidation of the membrane of the membrane module structure (1). As a result, when the membrane is deconsolidated and the dirt on the membrane surface is removed at the same time, the pressure gauges (P1), (P1) before and after the membrane, that is, on the upstream and downstream sides of the membrane module structure (1). The pressure difference appearing in P2) is the initial value, for example, 8.5 kg / cm ² (10
The value returns to the initially measured value (when using a kilo pump), but when the deterioration of the membrane itself progresses, the above pressure difference also changes. Therefore, by detecting the above-mentioned pressure difference after completion of the cleaning step, it is possible to know whether or not the cleaning operation was appropriate. Further, using this value as a guideline, this is at a certain level (preferably the initial value). It is also possible to judge that the time when it reaches about 1.5 times) is the time to replace the membrane. As a similar method for detecting the deterioration of the membrane, the electric conductivity of the concentrated water can be used in addition to the above. Furthermore, in the water treatment device of the present invention, during chemical washing,
By switching the three-way valve (5) with the calendar timer (20), raw water flows into the bypass line (7), passes through the low flow rate orifice (19), and the chemical feeder (ejector for sucking chemicals) (6) The chemical solution can be made to act on the inside of the membrane module structure (1) through the cleaning, and after the chemical washing, the calendar timer (20) performs flushing as many times as necessary to remove the drainage solution remaining on the membrane. Can be thoroughly washed away.

【The invention's effect】

Since the present invention has the above features, it has the following effects. Since the membrane can be automatically cleaned at an arbitrary time and the membrane can be prevented from being consolidated, the amount of water produced does not decrease. The durability of the film is improved and it can be used for a long time. The maintenance and management of the device can be carried out at low cost and without human labor. By checking the pressure difference between the upstream side and the downstream side via the membrane, it is possible to determine whether or not the desired water washing operation has been appropriately performed and the timing of membrane replacement. It is not necessary to separately provide a pump dedicated to cleaning, and chemicals can be injected into the raw water line of the membrane module structure and flushing can be performed with a simple structure, and the cost of the device can be reduced.

[Brief description of drawings]

FIG. 1 is a flow chart showing an embodiment of the present invention. (1) ...... Membrane module assembly (2) …… Concentrated water line, (3) …… Flushing valve (4) …… Raw water line (5) …… Three-way valve (7) …… Bypass line (P1), (P2) ...... Pressure gauge (20) ...... Calendar timer

Claims (1)

[Claims] 1. A flushing valve (3) is installed in a concentrated water line (2) on one end side of a membrane module structure (1), and a chemical feeder is attached to a raw water line (4) on the other end side.
Connect the chemical injection bypass line (7) with (6), install a three-way valve (5) for flow path switching, and
A pair of pressure gauges (P) for detecting the pressure difference between the upstream side and the downstream side of the membrane module structure (1).
A membrane module type water treatment device, characterized in that, in addition to installing (1) and (P2), a calendar timer (20) for continuously operating the three-way valve (5) is provided.