JP7288846B2 - Method of operating water treatment equipment and water treatment equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method of operating a water treatment facility and a water treatment facility, and relates to a technique for using water treatment methods with different treatment methods in combination.

1. In many water treatment plants, a single water treatment method is used to deal with raw water with large fluctuations in water quality.

2. A general water treatment plant is planned based on the planned maximum daily water supply volume, and has a surplus capacity for the average water supply volume.

3. At a water purification plant that employs multiple water treatment methods, water purification plant staff determine and operate the system operation of each treatment method based on the raw water quality and water demand.

4. In many cases, water is sent from a clean water reservoir in a water treatment plant to a higher distribution reservoir by a water pump, and then distributed to consumers by gravity flow from the distribution reservoir. In this case, the operation/stop of the water pump is controlled by the water level of the reservoir, and the operation/stop of the water treatment is controlled by the water level of the reservoir. Furthermore, when the scale of the water purification plant is large, there are cases in which the number of water pumps is controlled or the amount of purified water is controlled by controlling the number of water pumps or inverter control.

5. Patent Literature 1 discloses an operation method for changing the treatment amounts of a plurality of treatment methods in response to fluctuations in the required amount of water supply and changes in water quality.

Patent No. 5072050

When dealing with a single water treatment method, water treatment may become difficult when the water quality load increases, and conversely, when the water quality load decreases, excessive power and chemicals may be consumed, which is uneconomical.

When planning facilities based on the planned maximum daily water supply, the number of days when the planned maximum daily water supply is required is limited, and on many days it is sufficient to process the average water supply. If a treatment method is used, the more suitable method should be preferentially operated according to the raw water conditions.

In addition, if the system operation of multiple water treatment methods is judged and operated by water purification plant staff, it is expected that the number of technical staff will decrease in the future. It may become difficult to deal with fluctuations.

In addition, when water is sent from a clean water reservoir in a water treatment plant to a higher distribution reservoir using a water pump, if the water treatment is controlled only by the water level of the clean water reservoir, the capacity of the water pump will be greater than the water distribution volume, so the required water supply The amount of water and the water level of the clean water reservoir are not linked, making it difficult to operate the water purification facility according to the required amount of water supply.

What is disclosed in Patent Document 1 is to change the treatment amount of each treatment method by the filtration rate and the membrane filtration flux, which is accompanied by changes in treated water quality and operating conditions, so appropriate monitoring is required, and unmanned operation unsuitable for A large number of systems is required to change the number of systems in operation, and flexible application becomes difficult when the scale is small.

An object of the present invention is to solve the above problems, and to provide a method of operating a water treatment facility and a water treatment facility.

In order to solve the above problems, a method for operating a water treatment facility according to the present invention uses both a priority water treatment facility that operates preferentially and a non-priority water treatment facility that operates non-preferentially, In a method for operating a water treatment facility in which treated water is supplied from the facility to a first treated water tank and the treated water in the first treated water tank is distributed downstream through a second treated water tank, the priority water treatment facility comprises: Start at the priority operation water level set to the middle level of the first treated water tank, stop at the first tank upper limit water level set to the high level of the first treated water tank, and the non-prioritized water treatment facility is set to the low level of the second treated water tank. It is characterized in that it can be operated at the start permission water level set to .

In the method for operating a water treatment facility according to the present invention, the treated water in the first treated water tank is supplied to the second treated water tank via the water pump, and the water pump is set to the middle level of the second treated water tank. It is characterized by starting at the water supply pump starting water level and stopping at the second tank upper limit water level set to the high level of the second treated water tank.

In the method for operating a water treatment facility according to the present invention, the second treated water tank is arranged at a lower level than the first treated water tank, and treatment is allowed to flow naturally from the first treated water tank to the second treated water tank via a valve. Water is supplied, and the valve is opened at the valve open water level set to the middle level of the second treated water tank and closed at the second tank upper limit water level set to the high level of the second treated water tank.

In the method for operating a water treatment facility according to the present invention, the control device activates the non-priority water treatment facility when the water level of the first treated water tank is a non-priority operation water level set to a middle level lower than the priority operation water level, The non-prioritized water treatment equipment is stopped when the water level of the first treated water tank exceeds the non-prioritized stop water level, which is the same water level as the priority operation water level set to the middle level.

In the method for operating a water treatment facility according to the present invention, the control device activates the non-priority water treatment facility when the water level of the first treated water tank is a non-priority operation water level set to a middle level lower than the priority operation water level, The non-priority water treatment equipment is stopped when the water level of the first treated water tank exceeds the upper limit water level of the first treated water tank set to a high level.

In the method for operating a water treatment facility according to the present invention, the control device activates the non-prioritized water treatment facility when the water level of the first treated water tank is the same non-prioritized operation water level as the priority operation water level set to the middle level. The non-priority water treatment equipment is stopped when the water level of the first treated water tank exceeds the upper limit water level of the first treated water tank set to a high level.

In the method of operating a water treatment facility according to the present invention, water treatment facilities having different water treatment methods are used together, the value of a specific water quality item contained in raw water is used as a selection index, and when the selection index is equal to or less than a threshold, one The water treatment facility is designated as a priority water treatment facility, and the other water treatment facility is operated as a non-priority water treatment facility, and when the selection index exceeds the threshold value, the other water treatment facility is designated as a priority water treatment facility, and the one The water treatment facility is operated as a non-priority water treatment facility.

In the method of operating a water treatment facility according to the present invention, the priority water treatment facility and the non-priority water treatment facility treat water using membrane separation devices with different membrane areas per unit volume, and the unit in one membrane separation device It is characterized in that the membrane area per unit volume is larger than the membrane area per unit volume in the other membrane separation device.

In the method for operating a water treatment facility according to the present invention, a plurality of water treatment facilities using membrane separation devices having different membrane areas per unit volume are used in combination, and one membrane separation device has a membrane area per unit volume that is different from that of the other. If the membrane area per unit volume is larger than the membrane separation device and the turbidity of the water quality item is less than the threshold, the water treatment facility that uses the membrane separation device with the larger membrane area per unit volume is given priority. , when the turbidity of the water quality item exceeds the threshold, the water treatment facility using the other membrane separation device having a smaller membrane area per unit volume is set as the priority water treatment facility.

In the method of operating a water treatment facility according to the present invention, the priority water treatment facility and the non-priority water treatment facility treat water using membrane separation devices of different water treatment methods, and one membrane separation device uses a filtration membrane. It is a casing containing type membrane separation device that filters raw water to be supplied in a casing of a closed space containing the membrane separation device. It is characterized by being a tank immersion type membrane separation device that is immersed to filter raw water.

In the method of operating a water treatment facility according to the present invention, the priority water treatment facility and the non-priority water treatment facility treat water using water treatment facilities of different water treatment methods, and one of the water treatment facilities is a slow filtration device. and the other water treatment facility is characterized by being a coagulating sedimentation/rapid filtration system.

In the method of operating a water treatment facility according to the present invention, the priority water treatment facility and the non-priority water treatment facility treat water using water treatment facilities of different water treatment methods, and one of the water treatment facilities is a slow filtration device. and the other water treatment facility is a membrane separator.

In the method of operating a water treatment facility according to the present invention, the priority water treatment facility and the non-priority water treatment facility treat water using water treatment facilities with different water treatment methods, and one water treatment facility uses coagulation sedimentation/rapid It is a filtration device, and the other water treatment equipment is characterized by being a membrane separation device using a hollow fiber membrane.

The water treatment facility according to the present invention treats inflow raw water in parallel, uses membrane separation devices with different membrane areas per unit volume, and one membrane separation device has a membrane area per unit volume of the other membrane. A plurality of water treatment facilities larger than the membrane area per unit volume in the separation device, a turbidity measuring device that measures the turbidity of the influent raw water, a clean water reservoir that supplies treated water from both water treatment facilities, and a clean water reservoir Equipped with a water reservoir that supplies treated water via a water pump, a water level measuring device that measures the water level of each of the clean water reservoir and the water reservoir, and a control device that controls the start and stop of each water treatment facility and water pump, When the measured turbidity of the turbidity measuring device is equal to or less than the threshold value, the control device sets the water treatment facility using the membrane separation device having the larger membrane area per unit volume as the priority water treatment facility, and performs the turbidity measurement. When the measured turbidity of the device exceeds the threshold, the water treatment facility that uses the other membrane separation device with a smaller membrane area per unit volume is set as the priority water treatment facility, and the priority water treatment facility is lower than the priority operation water level set to the middle level, and stops when the water level of the reservoir exceeds the upper limit water level set to the high level of the reservoir. Operation is possible when the water level is below the allowable water level, the water pump is started when the water level in the reservoir is below the pump starting water level set to the middle level, and when the water level in the reservoir exceeds the reservoir upper limit water level set to the high level It is characterized by stopping.

In the present invention described above, the non-prioritized water treatment facility can be activated when the water level of the distribution reservoir drops and reaches the low non-prioritized operation water level, so efficient operation can be performed according to the actual water demand. That is, the priority water treatment facility can be operated at full capacity, and the non-priority water treatment facility can make up for the shortfall.

As a result, by preferentially operating the appropriate treatment facility according to the state of the raw water, it is possible to ensure reliable water quality, economical operation, and rational system operation.

Schematic diagram showing a water treatment facility in an embodiment of the present invention A cross-sectional view showing an example of a casing-containing membrane separation device in the same embodiment. FIG. 2 is a perspective view showing a membrane element of the casing-contained membrane separation device according to the same embodiment. A cross-sectional view showing an example of the tank immersion type membrane separation device in the same embodiment. Schematic diagram showing a control method in the case of operating the casing-contained membrane separation device and the tank immersion membrane separation device in the same embodiment. Schematic diagram showing the operating state of the water treatment facility according to the water level of the clean water reservoir in the same embodiment Schematic diagram showing the operating state of the water treatment facility according to the water level of the distribution reservoir in the same embodiment

Hereinafter, water treatment facilities according to embodiments of the present invention will be described with reference to the drawings. 1 to 7, this water treatment facility comprises a receiving well 1 and a mixing basin 2, and a plurality of water treatment facilities having different water treatment methods are arranged between a purified water reservoir 4 that stores purified water. Therefore, in the present embodiment, the casing-contained membrane separator 5 and the tank immersion membrane separator 6 are arranged in parallel and used together. As water treatment equipment of other different water treatment methods, there are a slow filtration device, a rapid filtration device, and the like, which will be described later. A receiving well 1 is provided with a turbidity measuring device 11 for measuring the turbidity of raw water.

The clean water reservoir 4 as the first treated water tank communicates with the distribution reservoir 13 as the second treated water tank via the water pump 12 .

It also has a control device 14 for controlling the operation of the casing-in-type membrane separator 5 and its auxiliary equipment, the tank immersion-type membrane separator 6 and its auxiliary equipment, and the water pump 12 .

In the present embodiment, one of the casing-contained membrane separators 5 is a water treatment facility having a larger membrane area per unit volume than the other submerged membrane separator 6 . The purified water reservoir 4 and the water distribution reservoir 13 are provided with water level measuring devices 15 and 16 for measuring the respective water levels.

The control device 14 uses the value of a specific water quality item contained in the raw water, here turbidity, as a selection index. As shown in FIG. 5, when the measured turbidity of the turbidity measuring device 11 is equal to or lower than the intermediate threshold value X1, the casing-containing membrane separation device 5, which is one of the membrane separation devices having a larger membrane area per unit volume, is used. The water treatment facility to be used is set as the priority water treatment facility, and the water treatment facility using the tank immersion type membrane separation device 6, which is the other membrane separation device with a smaller membrane area per unit volume, is set as the non-priority water treatment facility. do.

When the measured turbidity of the turbidity measuring device 11 exceeds the threshold value X1, the water treatment facility using the tank immersion type membrane separation device 6, which is the other membrane separation device with a smaller membrane area per unit volume, is designated as the priority water treatment facility. The water treatment facility using the casing-in-type membrane separation device 5, which is one of the membrane separation devices having the larger membrane area per unit volume, is set as the non-priority water treatment facility.

Here, the casing-in-type membrane separation device 5 is set as the priority water treatment facility, and the tank immersion type membrane separation device 6 is set as the non-priority water treatment facility.

The turbidity measuring device 11 may be installed in an inflow pipe through which raw water flows into the receiving well 1, and when the raw water is taken out by a sampling pump, it can be installed in a remote location such as an administration building.

As shown in FIG. 6, when the water level of the clean water reservoir 4 measured by the water level measuring device 15 is equal to or lower than the priority operation water level M3 set to the middle level, the control device 14 controls the casing-containing membrane separation device 5 of the priority water treatment facility. is started, and when the priority stop water level (first tank upper limit water level) H set at the high level of the clean water treatment reservoir 4 is exceeded, the casing-containing membrane separator 5 of the priority water treatment facility is stopped.

The control device 14 enables the submerged membrane separation device 6 of the non-priority water treatment facility to operate when the water level of the distribution reservoir 13 measured by the water level measuring device 16 is lower than the activation permission water level M1 set to a low level. Furthermore, when the water level of the clean water reservoir 4 is lower than the non-prioritized operation water level M2 set to the middle level, the submerged membrane separator 6 of the non-priority water treatment facility is started, and the water level of the clean water reservoir 4 is set to the middle level. When the non-prioritized stop water level M3, which is set to the same water level as the priority operation water level M3, is exceeded, the submerged membrane separator 6 of the non-prioritized water treatment facility is stopped.

The submerged membrane separator 6 of the non-priority water treatment facility can also be operated as follows. That is, when the water level of the clean water reservoir 4 is lower than the non-prioritized operation water level M2 set to the middle level, the submerged membrane separator 6 of the non-priority water treatment facility is started, and the water level of the clean water reservoir 4 is set to the high level. When the non-prioritized stop water level H, which is set to the same water level as the stop water level (first tank upper limit water level) H, is exceeded, the tank immersion membrane separator 6 of the non-prioritized water treatment facility is stopped.

Furthermore, the submerged membrane separator 6 of the non-priority water treatment facility can also be operated as follows. That is, when the water level of the clean water reservoir 4 is equal to or lower than the non-prioritized operation water level M3 set to the same water level as the priority operation water level M3 of the casing-containing membrane separation device 5 of the priority water treatment facility set to the middle level, the non-priority water treatment facility When the tank immersion type membrane separation device 6 is started and the water level of the purified water reservoir 4 exceeds the non-prioritized stop water level H set to the same water level as the priority stop water level (first tank upper limit water level) H set to a high level, non-prioritized water treatment is performed. Stop the submerged membrane separator 6 of the facility.

The control device 14 activates the water pump 12 when the water level of the distribution reservoir 13 is set to a medium level or lower than the water distribution pump starting water level M2, and sets the water level of the distribution reservoir 13 to a high level. When the upper limit water level)H is exceeded, the water pump 12 is stopped.
(Casing-type membrane separator)
The casing-containing type membrane separation device 5 is a casing-containing type membrane separation device that filters the entire amount of raw water supplied to the casing of the closed space containing the filtration membrane. For example, the structure shown in FIGS. It has a plurality of basic membrane units. In this embodiment, the film material is exemplified by ceramics, but the present invention is not limited to the film material or shape. In addition, there is no limitation by the form such as so-called internal pressure type or external pressure type.

Here, the membrane element 101 is composed of a plurality of ceramic molded bodies 101a each having a substantially rectangular parallelepiped shape, and the porous ceramic molded bodies 101a are bonded to each other via a bonding material layer 101b. A plurality of through channels 104 are formed in the membrane element 101 so as to penetrate between a pair of opposing end faces 102 and 103 . The inner surface side of the through channel 104 forms the primary side, and the outer surface side of the membrane element 101 forms the secondary side.

A plurality of slits 105 are formed in the membrane element 101 . The slit 105 extends in the axial direction of the through channel 104 and has a groove shape that opens to the side surface 106 of the membrane element 101 , and both ends of the slit 105 are closed near the end surfaces 102 and 103 of the membrane element 101 . .

The membrane element 101 is housed inside a casing 112 . The casing 112 has an upper primary chamber 114 formed in its upper portion and a lower primary chamber 115 formed in its lower portion. The upper end portion of the membrane element 101 is exposed in the upper primary chamber, the lower end portion of the membrane element 101 is exposed in the lower primary chamber 115 , and the through channel 104 communicates with the upper primary chamber 114 and the lower primary chamber 115 .

The raw water inlet 109 of the lower primary chamber 115 of the casing 112 is in communication with the raw water supply system 130 through the first valve 116 , and communicated with the backwash water discharge system 131 through the second valve 118 . .

The casing 112 has a treated water outlet 110 on its side, and the treated water outlet 110 communicates with the space surrounding the secondary side of the membrane element 101 . The treated water outlet 110 is communicated with a treated water system 132 via a third valve 117 and communicated with a backwash water supply system 133 via a fourth valve 119 .

A pressurized gas supply system 134 communicates with the pressurized gas inlet 111 of the upper primary chamber 114 of the casing 112 via a fifth valve 120 .

The casing-containing membrane separator 5 generally consumes less power than the submerged membrane separator 6 .
(Tank immersion type membrane separator)
In the tank immersion type membrane separation device 6, a housing having an open space containing a filtration membrane is immersed in a tank for storing raw water, and the raw water in the tank is circulated inside and outside the housing, and the membrane surface of the filtration membrane is circulated. A submerged membrane separator for filtering a solid-liquid mixed-phase flow flowing in a so-called cross-flow is constructed, for example, with the structure shown in FIG. In FIG. 4, one submerged membrane separation apparatus 6 is disclosed as an example. In this embodiment, a plurality of submerged membrane separators 6 are arranged inside the treatment tank 7 . As described above, the present invention is not limited by the membrane material or shape, nor is it limited by the so-called internal pressure type, external pressure type, or the like.

Here, the tank immersion type membrane separation device 6 has a plurality of tubular membrane elements 51 and a membrane case 52 as a housing for accommodating these membrane elements 51 . The membrane case 52 has a rectangular cross section and is open at the upper and lower ends to form an open space.

Each membrane element 51 has a filtration membrane 54 attached to the surface of a porous tubular support 53 made of ceramics, and the inside communicates with a treated water lead-out system (not shown) for leading out treated water.

Each membrane element 51 is arranged with the axial direction (longitudinal direction) along the horizontal direction, and is arranged in parallel with a predetermined interval. Between the membrane surfaces of the filtration membranes 54 of the membrane elements 51 that face each other, flow channels 56 that are open both upward and downward are formed. Below the membrane element 51, an air diffuser 57 capable of adjusting the air diffusion amount is provided.

The submerged membrane separator 6 can generally treat raw water with higher turbidity than the casing-in-type membrane separator 5 .

The operation of the above configuration will be described below.

The turbidity of the raw water flowing into the receiving well 1 is measured by the turbidity measuring device 11 . The control device 14 determines priority water treatment facilities and non-priority water treatment facilities using turbidity as a selection index. Here, assuming that the measured turbidity is equal to or lower than the intermediate threshold value X1, the casing-in-type membrane separation device 5 is set as the priority water treatment facility, and the tank immersion type membrane separation device 6 is set as the non-priority water treatment facility.

The control device 14 starts the water pump 12 to send the treated water of the clean water reservoir 4 to the water reservoir 13 when the water level of the water reservoir 13 is equal to or lower than the water pump starting water level M2.

When the water level in the clean water reservoir 4 drops below the priority operating water level M3, the casing-containing membrane separator 5 of the priority water treatment facility is activated to treat the raw water in the mixing basin 2 and supply it to the clean water reservoir 4.

If the water level of the distribution reservoir 13 continues to drop, and the water level of the distribution reservoir 13 is lower than the water pump starting water level M2 and higher than the non-prioritized water treatment equipment start-up permission water level M1, the submerged membrane of the non-prioritized water treatment equipment The separation device 6 is not operated, and the operation of the water pump 12 is continued while the operation of the casing-containing membrane separation device 5 of the priority water treatment facility is continued.

Furthermore, when the water level of the distribution reservoir 13 drops below the activation permission water level M1, activation of the submerged membrane separator 6 of the non-priority water treatment facility is permitted. In the purified water reservoir 4, when the water level becomes lower than the non-prioritized operating water level M2 of the non-priority water treatment facility, the tank immersion type membrane separation device 6 of the non-priority water treatment facility is activated in addition to the casing-contained membrane separator 5 of the priority water treatment facility. to drive.

When the water supply amount of the water pump 12 exceeds the water distribution amount, the water level of the reservoir 13 rises, and when the water level reaches the water pump stop water level H, the water pump 12 is stopped. During this time, even if the water level of the distribution reservoir 13 rises and exceeds the activation permission water level M1 of the non-priority water treatment facility, the operation of the submerged membrane separator 6 of the non-priority water treatment facility continues.

The control device 14 causes the water level of the clean water reservoir 4 to rise by operating the casing-housed membrane separator 5 of the priority water treatment facility and the submerged tank-type membrane separator 6 of the non-priority water treatment facility. When it exceeds the non-prioritized stop water level M3 set to the same water level as the priority operation water level M3 set to the same level, the submerged membrane separator 6 of the non-priority water treatment facility is stopped.

Furthermore, when the water level of the clean water reservoir 4 measured by the water level measuring device 15 exceeds the priority stop water level (first tank upper limit water level) H set to the high level of the clean water reservoir 4, the controller 14 controls the casing housing type of the priority water treatment facility. Stop the membrane separator 5 .

The submerged membrane separator 6 of the non-priority water treatment facility can also be operated as follows. That is, when the water level of the clean water reservoir 4 is lower than the non-prioritized operation water level M2 set to the middle level, the submerged membrane separator 6 of the non-priority water treatment facility is started, and the water level of the clean water reservoir 4 is set to the high level. When the non-prioritized stop water level H, which is set to the same water level as the stop water level (first tank upper limit water level) H, is exceeded, the tank immersion membrane separator 6 of the non-prioritized water treatment facility is stopped.

Furthermore, the submerged membrane separator 6 of the non-priority water treatment facility can also be operated as follows. That is, when the water level of the clean water reservoir 4 is equal to or lower than the non-prioritized operation water level M3 set to the same water level as the priority operation water level M3 of the casing-containing membrane separation device 5 of the priority water treatment facility set to the middle level, the non-priority water treatment facility When the tank immersion type membrane separation device 6 is started and the water level of the purified water reservoir 4 exceeds the non-prioritized stop water level H set to the same water level as the priority stop water level (first tank upper limit water level) H set to a high level, non-prioritized water treatment is performed. Stop the submerged membrane separator 6 of the facility.

As described above, the submerged membrane separation device 6 of the non-priority water treatment facility can be started when the water level of the distribution reservoir 13 decreases and reaches the low non-priority operation water level M1, so that the water flows out from the distribution reservoir 13. Efficient operation can be performed according to actual water demand. That is, it is possible to operate the casing-contained membrane separator 5 of the priority water treatment facility at full capacity and compensate for the shortfall by operating the submerged tank membrane separator 6 of the non-priority water treatment facility. As a result, while ensuring reliable water quality according to the turbidity of the raw water, the tank immersion type membrane separation device 6, which consumes more power than the casing-containing type membrane separation device 5, can be used to meet only the shortage of water demand. By operating the system, economical operation becomes possible and rational system operation becomes possible.

In the above description, when the turbidity exceeds the threshold value X1, the settings of the priority water treatment equipment and the non-priority water treatment equipment are changed, the tank immersion type membrane separation device 6 is set as the priority water treatment device, and the casing housing type membrane separation device 5 are operated as non-priority water treatment facilities. The casing-containing membrane separator 5 stops when the turbidity reaches X2. In this case, the submerged membrane separator 6 can cope with higher turbidity of the raw water than the membrane separator 5 stored in the casing, so that the operation is safer.

In the above embodiment, it is also possible to replace the water pump 12 with a valve. In this case, the water distribution reservoir 13 is arranged at a position lower than the clean water reservoir 4, and the valve is opened and closed with the water pump stop water level as the valve open water level and the water pump start water level as the valve closed water level.

Other combinations of different water treatment systems include, for example, a combination of a slow filtration system and a coagulating sedimentation/rapid filtration system. In this case, for example, when the turbidity is 10 degrees or less (preferably turbidity of 5 degrees or less), the slow filtration device is the priority water treatment facility, and the coagulating sedimentation/rapid filtration device is the non-priority water treatment facility. . When the turbidity exceeds 10 degrees, the slow sand filtration equipment is treated as non-priority water treatment equipment, and the coagulating sedimentation/rapid filtration equipment is treated as priority water treatment equipment.

Another combination of different water treatment methods is, for example, a combination of a slow filtration device and a membrane separation device. In this case, for example, when the turbidity is 10 degrees or less (preferably turbidity of 5 degrees or less), the slow filtration device is the priority water treatment facility, and the membrane separation device is the non-priority water treatment facility. When the turbidity exceeds 10 degrees, the slow sand filter is used as non-priority water treatment equipment, and the membrane separator is used as priority water treatment equipment. When the turbidity exceeds 100 degrees, it is difficult to operate the membrane separator alone, and pretreatment for turbidity removal is required.

Furthermore, other combinations of different water treatment methods include, for example, a combination of a coagulation sedimentation/rapid filtration device and a membrane separation device using a hollow fiber membrane. In this case, for example, when the turbidity is 5 degrees or less, the membrane separator using a hollow fiber membrane is the priority water treatment equipment, and the coagulating sedimentation/rapid filtration equipment is the non-priority water treatment equipment. When the turbidity exceeds 5 degrees, the membrane separator using a hollow fiber membrane is treated as non-priority water treatment equipment, and the coagulation sedimentation/rapid filtration equipment is treated as priority water treatment equipment.

1 Receiving Well 2 Mixing Tank 4 Clean Water Reservoir 5 Casing-type Membrane Separator 6 Submersion-type Membrane Separator 11 Turbidity Measuring Device 12 Water Pump 13 Distributing Reservoir 14 Controller 15, 16 Water Level Measuring Device

Claims (14)

A priority water treatment facility operated preferentially and a non-priority water treatment facility operated non-preferentially are used together, and treated water is supplied from both water treatment facilities to the first treated water tank, and the first treated water tank In a method for operating a water treatment facility that distributes treated water downstream through a second treated water tank,
The priority water treatment facility is started at the priority operation water level set to the middle level of the first treated water tank, stopped at the first tank upper limit water level set to the high level of the first treated water tank,
A method of operating a water treatment facility, wherein the non-priority water treatment facility can be operated at a starting permission water level set to a low level in the second treatment tank. The treated water in the first treated water tank is supplied to the second treated water tank via the water pump,
The water supply pump is started at the water supply pump starting water level set at the middle level of the second treated water tank, and stopped at the second tank upper limit water level set at the high level of the second treated water tank. A method of operating the described water treatment facility. The second treated water tank is arranged at a lower level than the first treated water tank, and the treated water is supplied from the first treated water tank to the second treated water tank by gravity flow through a valve,
2. The valve according to claim 1, wherein the valve is opened at the valve open water level set at the middle level of the second treated water tank and closed at the second tank upper limit water level set at the high level of the second treated water tank. How to operate a water treatment facility. The control device activates the non-prioritized water treatment equipment when the water level of the first treated water tank is a non-prioritized operation water level set to a middle level lower than the priority operation water level, and sets the water level of the first treated water tank to a middle level. 2. The method of operating a water treatment facility according to claim 1, wherein the non-prioritized water treatment facility is stopped when the water level exceeds a non-prioritized stop water level that is the same as the priority operation water level. The control device activates the non-prioritized water treatment equipment when the water level of the first treated water tank is a non-prioritized operation water level set to a middle level lower than the priority operation water level, and sets the water level of the first treated water tank to a high level. 2. The method of operating a water treatment facility according to claim 1, wherein the non-priority water treatment facility is stopped when the upper limit water level of the first tank is exceeded. The control device activates the non-prioritized water treatment equipment when the water level of the first treated water tank is the same as the priority operated water level set to the middle level and the non-prioritized operation water level, and the water level of the first treated water tank rises to a high level. 2. The method of operating a water treatment facility according to claim 1, wherein the non-priority water treatment facility is stopped when the set first tank upper limit water level is exceeded. Combined use of water treatment facilities with different water treatment methods,
The value of a specific water quality item contained in the raw water is used as a selection index, and when the selection index is below the threshold, one water treatment facility is operated as a priority water treatment facility and the other water treatment facility is operated as a non-priority water treatment facility. and operating the other water treatment facility as a priority water treatment facility and operating the one water treatment facility as a non-priority water treatment facility when the selection index exceeds the threshold. 7. The method of operating a water treatment facility according to any one of 1 to 6. The priority water treatment facility and the non-priority water treatment facility treat water using membrane separation devices with different membrane areas per unit volume, and the membrane area per unit volume in one membrane separation device is the same as that in the other membrane separation device. 8. The method of operating a water treatment facility according to any one of claims 1 to 7, wherein the membrane area per unit volume is larger. A plurality of water treatment facilities using membrane separation devices with different membrane areas per unit volume are used together, and the membrane area per unit volume in one membrane separation device is larger than the membrane area per unit volume in the other membrane separation device. ,
When the turbidity of the water quality item is less than the threshold, the water treatment facility that uses the membrane separation device with the larger membrane area per unit volume is prioritized,
8. The water according to claim 7, wherein when the turbidity of the water quality item exceeds the threshold, the water treatment facility using the other membrane separation device with a smaller membrane area per unit volume is set as the priority water treatment facility. How to operate treatment equipment. The priority water treatment facility and the non-priority water treatment facility treat water using membrane separation equipment with different water treatment methods, and one membrane separation equipment supplies raw water to the casing of the closed space containing the filtration membrane. The other type of membrane separation device is a tank immersion type membrane separation device in which an open space housing a filtration membrane is immersed in a tank for storing raw water to filter raw water. 8. The method of operating a water treatment facility according to any one of claims 1 to 7, wherein the water treatment facility is a device. The priority water treatment facility and the non-priority water treatment facility treat water using water treatment facilities with different water treatment methods. 8. The method of operating a water treatment facility according to any one of claims 1 to 7, wherein the water treatment facility is a rapid filtration device. The priority water treatment facility and the non-priority water treatment facility treat water using water treatment facilities with different water treatment methods, one water treatment facility is a slow sand filtration device, and the other water treatment facility is a membrane separation device. The method for operating a water treatment facility according to any one of claims 1 to 7, characterized in that: The priority water treatment facility and the non-priority water treatment facility treat water using water treatment facilities with different water treatment methods. 8. The method for operating a water treatment facility according to any one of claims 1 to 7, wherein the apparatus is a membrane separator using a membrane. Inflow raw water is treated in parallel, membrane separation devices with different membrane areas per unit volume are used, and the membrane area per unit volume in one membrane separation device is the same as the membrane area per unit volume in the other membrane separation device. a plurality of larger water treatment plants;
a turbidity measuring device for measuring the turbidity of the influent raw water;
A clean water reservoir that supplies treated water from both water treatment facilities,
A distribution reservoir that supplies treated water from the clean water reservoir via a water pump,
a water level measuring device for measuring the water level of each of the clean water reservoir and the distribution reservoir;
Equipped with a control device that controls the start and stop of each water treatment facility and water pump,
When the measured turbidity of the turbidity measuring device is equal to or less than the threshold, the control device sets the water treatment facility using the membrane separation device having the larger membrane area per unit volume as the priority water treatment facility,
When the measured turbidity of the turbidity measuring device exceeds the threshold, the water treatment facility using the other membrane separation device with a smaller membrane area per unit volume is set as the priority water treatment facility,
The priority water treatment facility starts when the water level of the clean water reservoir is lower than the priority operating water level set at the middle level, and stops when it exceeds the upper limit water level set at the high level of the clean water reservoir.
The non-priority water treatment facility shall be operable when the water level of the reservoir is lower than the start-up permission water level set at a low level,
A water treatment facility characterized in that the water supply pump is started when the water level in the reservoir is lower than the pump starting water level set at the middle level, and is stopped when the water level in the reservoir exceeds the upper limit water level set at the high level. .

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