JP4594764B2 - Pretreatment equipment for water quality measurement - Google Patents

Description

  The present invention relates to a pretreatment device for water quality measurement, which is arranged in a front stage of a water quality measurement unit that detects mixing of a soluble foreign substance in water as part of risk management in the water supply field.

  In the water supply field, detection of foreign matters mixed in water has been carried out by raising fish in an aquarium and monitoring the behavior / life of fish. However, since anxiety such as terrorism has increased recently, and a more sensitive detection technique has been demanded, a sensor using the respiratory activity of microorganisms as an index has been developed (Japanese Patent Laid-Open No. 11-37969).

  In such a method using microorganisms, generally, a small amount of water to be detected (hereinafter referred to as sample water) is required compared to that used for fish breeding (in the case of fish breeding, several hundred milliliters to several Liters per minute, or several milliliters to tens of milliliters per minute when using microorganisms).

  By the way, since a small amount of sample water is passed through a thin pipe having an inner diameter of several millimeters, mixing of turbidity may cause the pipe to be blocked. Therefore, a pretreatment process is required in the preceding stage of such a water quality measurement unit to supply a small amount of sample water from which turbidity has been removed continuously and stably. Conventionally, in such a pretreatment process, a process using a hollow fiber membrane capable of maintaining a constant filtration flow rate while removing fine particles has been performed. In addition, when detecting dissolved components in water by the respiratory activity in the water quality measurement unit, there is a problem that the detection accuracy varies depending on the season because the concentration at which oxygen as a respiratory substrate is dissolved in the sample water depends on the water temperature. Therefore, it is necessary to adjust the dissolved oxygen concentration by increasing the water temperature by heating the pipe with a heater when the sample water after the hollow fiber membrane treatment is stored in the water tank and blowing air, or when the water temperature is low.

  As described above, it is important to remove turbidity by pretreatment when detecting contamination by using the respiratory activity of microorganisms. However, in general, flow rate is always used for removing turbidity using a hollow fiber membrane. The problem of decline is a concern. Therefore, the lifetime of the membrane is prolonged by devising the flow path configuration, the pore size of the membrane, and the backwashing technique.

  In addition, the dissolved oxygen concentration of the sample water is an important parameter when detecting contamination by using the respiratory activity of microorganisms.

  The present invention has been made in consideration of such points, and can provide a sample water with a small flow rate for a long period of time, and can perform a more precise adjustment of dissolved oxygen concentration of the sample water. An object of the present invention is to provide a pre-processing apparatus for use.

  The present invention relates to a pretreatment device for water quality measurement that is disposed in front of a water quality measurement unit that inspects dissolved components in water based on the respiratory activity of microorganisms, and the raw water side into which raw water flows and the filtrate flow out. An external pressure type hollow fiber membrane module having a hollow fiber membrane divided into a permeation side, a filtration pump connected to the permeation side of the hollow fiber membrane module, and a post-filtration pump, which blows air into the filtrate water An air blowing mechanism, a temperature control mechanism installed at the subsequent stage of the air blowing mechanism, a cleaning mechanism for introducing pressurized gas to the raw water side and the permeation side of the hollow fiber membrane module, and a temperature control mechanism installed at the subsequent stage A pretreatment device for water quality measurement comprising a sample water tank and a control unit for controlling a filtration pump, an air blowing mechanism, a temperature control mechanism, and a cleaning mechanism.

  According to the present invention, raw water is filtered by the external pressure hollow fiber membrane module, and the driving force for the filtration is obtained by the filtration pump. The filtered filtered water is mixed with air in an air blowing mechanism, and then adjusted to an arbitrary temperature by a temperature control mechanism, thereby being adjusted to a predetermined dissolved oxygen concentration and supplied to a sample water tank. Further, the hollow fiber membrane can be cleaned at an arbitrary timing by the cleaning mechanism.

  In addition, when the hollow fiber membrane module is of the external pressure type, the membrane is less likely to be clogged than the internal pressure type, and the hollow fiber membrane can be used for a longer period of time. Further, by placing a filtration pump on the permeate side of the hollow fiber membrane and performing filtration by suction force, it is possible to prolong the life of the pump, which is generally considered to be weak against turbid contamination. By adjusting the temperature after blowing air into the filtered water, the dissolved oxygen concentration can be made higher than that of the raw water, and can also be made lower. Thus, the dissolved oxygen concentration is adjusted and the filtered water provided to the sample water tank is used in the water quality measurement unit. The hollow fiber membrane is automatically washed by a washing mechanism, so that the life can be extended.

  The present invention is a pretreatment device for water quality measurement, wherein the pore diameter of the hollow fiber membrane of the external pressure type hollow fiber membrane module is 0.2 micrometers or less.

  According to the present invention, microorganisms in raw water can be removed. If microorganisms in the raw water are continuously mixed on the permeate side, they will grow by adhering to the pipes, etc., causing clogging of the pipes, and the dissolved oxygen concentration will fluctuate due to oxygen consumption of the grown microorganisms. End up. According to the present invention, such a problem does not occur.

  The present invention is a pretreatment device for water quality measurement, characterized in that the external pressure type hollow fiber membrane module is of a vertically placed type and has a cross-flow channel for introducing raw water from the top and draining from the bottom.

  According to the present invention, by making the flow path of the hollow fiber membrane module a cross flow, solid matter is less likely to adhere to the surface of the hollow fiber membrane compared to the dead end type, and the filtration capacity is maintained for a long time. It becomes possible to do. Furthermore, turbidity staying in the hollow fiber membrane module can be effectively removed by introducing the raw water from the upper part of the hollow fiber membrane module and continuously discharging it from the lower part.

  The present invention is characterized in that the cleaning mechanism introduces pressurized gas from the permeation side of the external pressure hollow fiber membrane module, thereby removing the cause of fouling adhering to the hollow fiber membrane by the water pressure of filtered water. This is a pretreatment device for water quality measurement.

  According to the present invention, the contaminants on the surface of the hollow fiber membrane can be removed by the water pressure of the filtered water flowing backward from the permeate side to the raw water side, and the life of the hollow fiber membrane can be prolonged. Furthermore, when the hollow fiber membrane is a mixed membrane of a hydrophobic membrane and a hydrophilic membrane, the air flowing backward from the hydrophobic membrane leaks to the raw water side of the hollow fiber membrane, disturbing the water flow in the housing, and scribing effect And a better cleaning effect than in the case of using only a hydrophilic film can be obtained.

  The present invention provides a water quality measurement characterized in that the cleaning mechanism discharges the raw water on the raw water side to the outside of the hollow fiber membrane module by introducing a pressurized gas to the raw water side of the external pressure hollow fiber membrane module. It is a pre-processing device for use.

  According to the present invention, by introducing pressurized air to the raw water side from the upper part of the hollow fiber membrane module, turbidity deposited on the lower part of the raw water side of the hollow fiber membrane module can be effectively removed.

  The present invention provides an air vent having a valve on the raw water side of the hollow fiber membrane module, attaches a sensor to the raw water side, discharges raw water from the raw water side of the hollow fiber membrane module, refills the raw water, The raw water overflowing from the water is detected by a sensor, and the control unit closes the valve based on a signal from the sensor.

  After draining the raw water side of the hollow fiber membrane module, when filling the raw water again with the raw water side, it is necessary to vent the air. However, always releasing the air vent during filtration may cause unnecessary air contamination and may adversely affect the filtration. Therefore, it is possible to perform an effective process by detecting that the raw water side of the hollow fiber membrane module is completely filled with raw water with a sensor and closing the air vent with a valve. Furthermore, filtration can be restarted triggered by the detection of full water by the sensor.

  The present invention provides an air vent having a valve on the raw water side of the hollow fiber membrane module, and after discharging the raw water from the raw water side of the hollow fiber membrane module, a timer that measures the timing from when the raw water is refilled to when it is full And a control unit closes the valve based on a signal from a timer.

  According to the present invention, if the pressure of the raw water does not always vary so much, the time until the raw water is filled on the raw water side of the hollow fiber membrane module after the hollow fiber membrane cleaning is substantially constant. By using the timer, the air vent can be closed by the valve.

  The present invention is the pretreatment device for water quality measurement, wherein the sensor is a non-contact type sensor.

  According to the present invention, by using a non-contact type sensor, there is no fear of contamination as compared with a contact type sensor, for example, an electrode type sensor, and maintenance is facilitated. As a non-contact type sensor, there is a type for measuring the reflection / transmittance of red light.

  In the present invention, the cleaning mechanism introduces pressurized gas to the permeation side of the hollow fiber membrane module, removes the cause of fouling adhering to the hollow fiber membrane by the water pressure of filtered water, and then pressurizes the raw water side to the pressurized gas Is a pretreatment device for water quality measurement, characterized by draining raw water on the raw water side outward.

  According to the present invention, the pollutant on the raw water side of the hollow fiber membrane module can be effectively discharged to the outside after the pollutant on the permeate side of the hollow fiber membrane module is released into the hollow fiber membrane module. It is possible to prevent re-contamination due to the pollutant that has been released once and prolong the life of the hollow fiber membrane.

  The temperature control mechanism includes a pipe through which filtered water flows, a heater that surrounds the pipe, a heat insulating material that covers the outside of the heater, and a thermostat that operates a power source of the heater, and the control unit is based on temperature information of the filtered water. A pretreatment device for water quality measurement, characterized by controlling a thermostat.

  According to the present invention, the length of the piping necessary for the temperature rise can be kept short by raising the temperature of the filtered water with the heat of the heater and further efficiently using the heat with the heat insulating material. Furthermore, for example, by measuring the temperature of filtered water in a sample water tank and controlling the temperature control mechanism based on the temperature information, more accurate temperature management becomes possible.

  The temperature control mechanism of the present invention is characterized in that the temperature adjustment mechanism includes a pipe through which filtered water flows and a cover pipe that covers the outside of the pipe, and the temperature of the filtered water is adjusted by flowing a liquid at a desired temperature through the cover pipe. It is a pre-processing device for measurement.

  According to the present invention, by using a liquid at a desired temperature as a medium, efficient heat exchange can be achieved, and the temperature of the liquid as a medium can be adjusted based on temperature information of filtered water. .

  As described above, according to the present invention, it is possible to supply a small amount of continuous filtered water for a long period of time to a water quality inspection unit that inspects water quality based on the respiratory activity of microorganisms. Furthermore, the dissolved enzyme concentration of filtered water can be adjusted using a temperature adjustment mechanism, and it becomes possible to supply filtered water that can be measured with high accuracy to the water quality inspection unit.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 are diagrams showing an embodiment of a pretreatment device for water quality measurement according to the present invention.

  As shown in FIG. 1, the pretreatment device for water quality measurement according to the present invention is installed in the front stage of a water quality measurement unit 22 that examines dissolved components in water based on the respiratory activity of microorganisms.

  Such a pretreatment device includes a housing 20, and an external pressure hollow fiber membrane module 1 having a hollow fiber membrane 21 that is divided into a raw water side 1a through which the raw water flows and a permeate side 1b through which filtered water flows out. The filtration pump 2 connected to the permeation side 1b of the hollow fiber membrane module 1, the air blowing mechanism 9 installed in the subsequent stage of the filtration pump 2 and the air blowing mechanism 9 for blowing air into the filtrate water, and installed in the subsequent stage of the air blowing mechanism 9 A temperature control mechanism 3, a cleaning mechanism 4 for introducing pressurized gas (compressed air) to the raw water side 1 a and the permeation side 1 b of the hollow fiber membrane module 1, and a sample water tank installed at the subsequent stage of the temperature control mechanism 3 And 5.

  Among these, the external pressure type hollow fiber membrane module 1 becomes a vertical installation type, and forms the cross flow channel which flows in raw water from the upper part of the raw | natural water side 1a, and drains to the lower part of the raw | natural water side 1a. The hollow fiber membrane module 21 has a large number of holes having a hole diameter of 0.2 micrometers or less.

  The air blowing mechanism 4 has an air compressor 4a, and an open / close valve 6c is provided between the air compressor 4a and the raw water side 1a of the hollow fiber membrane module 1, and between the air compressor 4a and the permeate side 1b. An on-off valve 6d is provided.

  The raw water flows into the raw water side 1a of the hollow fiber membrane module 1 through the on-off valve 6a. When the raw water side 1a is filled with raw water, an air vent 23 for releasing the air in the raw water side 1a is connected between the raw water side 1a and the on-off valve 6c, and the on-off valve 6b and the sensor 7 are connected to the air vent 23. Are installed sequentially. Among these, the sensor 7 detects that the raw water overflowed from the raw water side 1a when the raw water side 1a is filled with the raw water. The sensor 7 is a non-contact sensor that measures the reflection / transmittance of red light.

  Further, an on-off valve 6e is installed between the permeation side 1b of the hollow fiber membrane module 10 and the filtration pump 2, and a drain pipe 24 having an on-off valve 6f is connected to the lower part of the raw water side 1b.

  As shown in FIG. 1, the air blowing mechanism 9 has an air pipe 9a and an air pump 8 that blows air into the air pipe 9a.

  Further, as shown in FIG. 2, the temperature adjustment mechanism 3 includes a pipe 3 a through which filtered water flows, a heater 10 surrounding the pipe 3 a, and a heat insulating material 11 that covers the outside of the heater 10. The heater 10 is operated by a thermostat 12. It has come to be.

  Further, the filtration pump 2, the thermostat 12 of the temperature control mechanism 3, the air compressor 4 a, the air pump 8, and the on-off valves 6 a, 6 b, 6 c, 6 d, 6 e, 6 f are driven and controlled by the control unit 25.

  A signal from the sensor 7 is input to the control unit 25, and a timer 26 is connected to the control unit 25. The timer 26 has a preset time for discharging the raw water from the raw water side 1a of the hollow fiber membrane module 1 and filling the raw water side 1a again with the raw water to fill the raw water 1a.

  Next, the operation of the present embodiment having such a configuration will be described.

  First, at the time of normal filtration, raw water is introduced into the raw water side 1a of the external pressure hollow fiber membrane module 1 from the upper part, and excess raw water flowing into the raw water side 1a is discharged from the lower part of the raw water side 1a. Filtrated water filtered by the hollow fiber membrane 21 (hereinafter also referred to as sample water) passes through the electromagnetic valve 6e from the permeate side 1b and is sucked into the filtration pump 2.

  The sample water discharged from the filtration pump 2 is mixed with the air supplied from the air pump 8 in the air blowing mechanism 9 and then reaches the temperature control mechanism 3. In the temperature control mechanism 3, the dissolved oxygen concentration of the sample water is adjusted, and then the sample water is sent into the sample water tank 5 and supplied to the water quality measuring unit 22 that inspects the water quality based on the respiratory activity of the microorganisms. In the figure, 6a, 6b, 6c, 6d, 6e, and 6f represent open / close valves (solenoid valves) controlled by the control unit 25, but the open / close valves that are opened during filtration are 6a, 6e, and 6f.

  Next, the operation during backwashing will be described. At the time of backwashing, all of the on-off valves 6a, 6e, 6f that were open at the time of filtration are first closed. Further, the filtration pump 2 is stopped. Next, the backwashing mechanism 4 is used, and the airflow generated by the air compressor 4a is blown into the permeation side 1b of the hollow fiber membrane module 1 through the on-off valve 6d. The surface of the hollow fiber membrane 21 is washed by the water pressure of the filtered water generated by the air flow. During this time, the on-off valves 6c and 6f are closed.

  Next, the on-off valve 6d is closed, and the on-off valves 6c and 6f are opened. Next, air pressure is applied to the raw water side 1a of the hollow fiber membrane module by the compressor 4a, and the pollutant and raw water adhering to the inner surface of the housing 20 efficiently from the raw water 1a side are discharged from the drain pipe 24 having the on-off valve 6f.

  After that, the on-off valve 6f is closed, and the raw water side 1a of the hollow fiber membrane module 1 is filled again with raw water. At that time, the on-off valve 6b is opened, and the internal air is released from the air vent 23 outward from the raw water side 1a. Whether the raw water 1a is filled with the raw water is confirmed by directly detecting the overflow water with the sensor 7. In this case, it may be confirmed that the raw water is filled in the raw water side 1a by setting the required time in the timer 26 in advance. Thereafter, the control unit 25 closes the on-off valve 6b based on information from the sensor 7 or information from the timer 26, and the filtering operation is repeated. All the above operations are performed by an operation command from the control unit 25.

  The operation of the temperature control mechanism 3 during this period will be described with reference to FIG. In FIG. 2, the sample water flows through the pipe 3a of the temperature control mechanism 3, and the temperature is adjusted by the heater 10 surrounding the pipe 3a. The heater 10 is further prevented from radiating heat by the heat insulating material 11 surrounding the heater 10, and as a result, an efficient temperature rise effect can be obtained. Further, the heater 10 is temperature-controlled by turning on / off the power by the thermostat 12. The temperature information of the sample water that is the basis for the temperature control is obtained by a resistance temperature detector or a thermocouple installed in the subsequent sample water tank 5, and the thermostat 12 is controlled by the control unit 25.

  Next, a modified example of the temperature control mechanism 3 will be described with reference to FIG. In the modification of the temperature control mechanism 3 shown in FIG. 3, the sample water flows in the pipe 3a, and the constant temperature liquid supplied from the constant temperature liquid circulation device 15 is circulated in the cover pipe 14 surrounding the pipe 3a. As a result, the temperature of the sample water in the pipe 3a is adjusted.

It is a block diagram which shows one Example of the pre-processing apparatus for the water quality measurement by this invention. It is a block diagram which shows a temperature control mechanism. It is a block diagram which shows the modification of a temperature control mechanism.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hollow fiber membrane module 1a Raw water side 1b Permeation side 2 Filtration pump 3 Temperature control mechanism 3a Piping 4 Back washing mechanism 4a Air compressor 5 Sample water tank 6a, 6b, 6c, 6d, 6e, 6f On-off valve 7 Sensor 8 Air pump 9 Air Blowing mechanism 10 Heater 11 Heat insulating material 12 Thermostat 14 Cover tube 15 Constant temperature liquid circulation device 20 Housing 21 Hollow fiber membrane 22 Water quality inspection unit 23 Air vent 25 Control unit

Claims (11)

In the pretreatment device for water quality measurement arranged in the front stage of the water quality measurement unit that examines dissolved components in water based on the respiratory activity of microorganisms,
An external pressure type hollow fiber membrane module having a hollow fiber membrane that divides the inside into a raw water side into which raw water flows and a permeate side from which filtered water flows out,
A filtration pump connected to the permeate side of the hollow fiber membrane module;
An air blowing mechanism installed after the filtration pump to blow air into the filtered water;
A temperature control mechanism installed after the air blowing mechanism;
A cleaning mechanism for introducing pressurized gas to the raw water side and the permeate side of the hollow fiber membrane module;
A sample water tank installed downstream of the temperature control mechanism;
A control unit for controlling a filtration pump, an air blowing mechanism, a temperature control mechanism and a cleaning mechanism;
A pretreatment device for water quality measurement, comprising:   The pretreatment device for water quality measurement according to claim 1, wherein the hollow fiber membrane of the external pressure hollow fiber membrane module has a pore diameter of 0.2 micrometers or less.   2. The pretreatment device for water quality measurement according to claim 1, wherein the external pressure type hollow fiber membrane module is of a vertical type and has a cross flow channel for introducing raw water from the upper part and draining from the lower part.   The cleaning mechanism removes the cause of fouling adhering to the hollow fiber membrane by the water pressure of filtered water by introducing a pressurized gas from the permeate side of the external pressure hollow fiber membrane module. Pretreatment device for water quality measurement.   The water quality according to claim 1, wherein the cleaning mechanism discharges raw water on the raw water side to the outside of the hollow fiber membrane module by introducing a pressurized gas to the raw water side of the external pressure hollow fiber membrane module. Pre-processing device for measurement.   An air vent with a valve is provided on the raw water side of the hollow fiber membrane module, and a sensor is attached to the raw water side. After discharging the raw water from the raw water side of the hollow fiber membrane module, the raw water is refilled and overflowed from the raw water side. 2. The pretreatment device for water quality measurement according to claim 1, wherein the raw water is detected by a sensor, and the control unit closes the valve based on a signal from the sensor. An air vent having a valve is provided on the raw water side of the hollow fiber membrane module,
After discharging the raw water from the raw water side of the hollow fiber membrane module, install a timer that measures the timing from when the raw water is refilled to when it is full, and the control unit closes the valve based on the signal from the timer The pretreatment device for water quality measurement according to claim 1, wherein   The pretreatment device for water quality measurement according to claim 6, wherein the sensor is a non-contact type sensor.   The cleaning mechanism introduces pressurized gas to the permeate side of the hollow fiber membrane module, removes the cause of fouling attached to the hollow fiber membrane by the water pressure of the filtered water, and then introduces pressurized gas to the raw water side. 2. The pretreatment device for water quality measurement according to claim 1, wherein raw water on the raw water side is drained outward. The temperature control mechanism includes a pipe through which filtered water flows, a heater surrounding the pipe, a heat insulating material that covers the outside of the heater, and a thermostat that operates the power supply of the heater,
The pretreatment device for water quality measurement according to claim 1, wherein the control unit controls the thermostat based on temperature information of the filtered water.   The temperature control mechanism has a pipe through which filtered water flows and a cover pipe that covers the outside of the pipe, and adjusts the temperature of the filtered water by flowing a liquid at a desired temperature in the cover pipe. Pretreatment device for water quality measurement.

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