JP2014188414A - Water treatment method and system - Google Patents

Abstract

To provide a water treatment method and a water treatment system which can perform suction of filtered water and supply of gas for backwashing with a common device and can simplify equipment.
A water treatment method comprising a filtration step of introducing treated water 1 into a filtration module 11 provided with a filter medium to obtain filtered water 2 and a backwashing step of washing the filter medium. The pressure reducing means 31 promotes the filtration with the filter medium by reducing the pressure of the gas phase portion 3 in contact with the filtered water 2 discharged from the filtrate extraction side 12 of the filtration module 11. In the backwashing step, the pressure reducing means 31 The gas 4 discharged from is supplied to the filtrate extraction side 12 of the filtration module 11 to wash the filter medium.
[Selection] Figure 3

Description

  The present invention relates to a water treatment method and a water treatment system, and more particularly to a water treatment method and a water treatment system using a filtration module provided with a filter medium.

  Conventionally, a method of performing solid-liquid separation using a filtration module provided with a filter medium is known. For example, Patent Document 1 discloses an immersion type filtration module (membrane module), which performs filtration by pump suction of the filtrate extraction side of the filtration module. It is disclosed that air is supplied from the take-out side by a compressor to clean the filter medium.

JP 2002-177746 A

  As disclosed in Patent Document 1, when performing filtration and backwashing with a filtration module, it is common to provide a filtration pump and a backwashing compressor, respectively. This is because the filtration pump is for sucking the filtered water, which is a liquid, while the backwash compressor is for sending out gas, and the fluids handled by both are different. However, there is a risk that the facilities will become large.

  The present invention has been made in view of the above circumstances, and its purpose is to provide water that can suck filtered water and supply backwashing gas with a common device, and can simplify equipment. The object is to provide a treatment method and a water treatment system.

  The water treatment method of the present invention that has been able to solve the above-described problems includes a process of introducing treated water into a filtration module equipped with a filter medium to obtain filtered water, and a backwash process of washing the filter medium. In the filtration process, in the filtration step, the gas phase part in contact with the filtrate discharged from the filtrate extraction side of the filtration module is depressurized by the decompression means to promote filtration with the filter medium and backwash. The process is characterized in that the gas discharged from the decompression means is supplied to the filtrate extraction side of the filtration module to wash the filter medium. According to the water treatment method of the present invention, it is possible to perform a filtration step and a backwashing step using a common decompression means, which eliminates the need for providing a blower or a compressor dedicated to backwashing and simplifies equipment. Can be achieved.

  It is preferable that a first opening and a second opening are provided on the filtrate extraction side of the filtration module. In this case, it is preferable that the filtered water is obtained from the first opening in the filtration step, and the gas discharged from the decompression means is supplied to the filtered water extraction side through the second opening in the backwashing step. By performing such a backwashing process, the filtered water remaining in the filtration module can be recovered, and the recovery rate of the filtered water can be increased. Furthermore, from the point of increasing the efficiency of backwashing, a filtered water flow path is provided in communication with the first opening, and an open / close device that opens and closes the flow path is provided in the filtered water flow path. In the backwashing step, when supplying the gas discharged from the decompression means to the filtered water extraction side through the second opening, it is preferable to close the opening / closing device after opening it for a predetermined time.

  In the filtration process, a filtrate flow path equipped with a filtrate water tank is provided in communication with the filtrate water extraction side of the filtration module. The filtration of the filter medium is preferably promoted by reducing the pressure of the gas phase portion of the filtrate water tank with a pressure reducing means. If a filtrate water tank is provided in the filtrate water flow path, it becomes difficult to accidentally suck filtrate water by the decompression means, and the pressure in the gas phase part can be easily adjusted.

  In the water treatment method of the present invention, it is preferable to repeat the filtration step and the backwashing step in a state where the gas phase portion of the filtrate flow channel (which may be provided with a filtrate water tank) is decompressed. By maintaining the pressure-reduced state of the gas phase portion of the filtered water flow path in the backwashing process, when the filtration process is performed after the backwashing process, it is possible to immediately perform filtration with a filter medium.

  In the water treatment method of the present invention, the filtration step and the backwashing step may be repeated while the decompression means is operating. In the water treatment method of the present invention, since the filtration step and the backwashing step can be performed by a common pressure reduction means, it is not necessary to stop the operation of the pressure reduction means every time the filtration step and the backwashing step are switched. Therefore, when the pressure reducing means is operated as described above, each process can be smoothly performed even when the filtration process and the backwash process are switched. Furthermore, it is possible to frequently switch between the filtration step and the backwashing step in a short cycle.

  In the water treatment method of the present invention, it is also preferable to use an anaerobic treatment liquid containing biogas as the water to be treated. In this case, it is preferable to use biogas generated from the anaerobic treatment liquid as the gas discharged from the decompression means in the backwashing step. By performing the backwashing process in this way, it is possible to suppress aerobic treatment of the anaerobic treatment liquid that is the water to be treated.

  The present invention also provides a water treatment system used in the water treatment method of the present invention. That is, the water treatment system of the present invention includes a filtration medium, a filtration module having a supply side where treated water is present and a filtered water extraction side where filtered water is present, with the filter medium interposed therebetween; Filtered water discharged from the filtered water extraction side, and a filtered water channel having a gas phase portion in contact with the filtered water; a decompression having a suction side and a discharge side and depressurizing the gas phase portion of the filtered water channel A suction channel provided in communication with the gas phase portion of the filtered water channel and the suction side of the decompression unit; an exhaust channel provided in communication with the discharge side of the decompression unit; an exhaust channel; A backwashing passage provided in communication with the filtrate extraction side of the filtration module; and an exhaust control means for controlling the flow of the gas discharged from the decompression means to the backwashing passage.

  The filtration module is preferably provided with a first opening and a second opening on the filtrate extraction side, the filtrate flow path communicates with the first opening, and the backwash flow path communicates with the second opening. . Moreover, it is preferable that the filtrate flow path is provided with an opening / closing device that opens and closes the flow path. Furthermore, it is preferable that the filtrate flow path has a filtrate water tank in which filtrate water is present and a gas phase portion is provided in the upper part.

  The water treatment system of the present invention is provided with an air supply channel in communication with at least one of the gas phase portions of the suction channel and the filtrate water channel, and the air supply channel is provided with an opening / closing device for opening and closing the channel. It is preferable. By providing the air supply channel in this way, the backwashing gas can be supplied to the suction side of the decompression means through the air supply channel, and the gas phase portion of the filtrate channel can be reduced in size. The air supply flow path is provided on one side communicating with at least one of the gas phase part of the suction flow path and the filtrate water flow path, but the other side may be opened to the atmosphere or provided connected with other equipment. Also good. For example, a gas holder may be provided in communication with the exhaust flow path, and the air supply flow path may be in communication with at least one of the gas phase portion of the suction flow path and the filtrate water flow path and the gas holder. Further, the filtration module is provided by being immersed in the water to be treated held in the filtration tank, and the air supply channel communicates with at least one of the gas phase part of the suction channel and the filtrate water channel and the gas phase part of the filtration tank. You may do it.

  The exhaust control means is preferably a three-way valve provided at one end of the backwash channel connected to the exhaust channel. By providing the three-way valve in this way, the gas discharged from the decompression means can be circulated through the backwash channel, or can be discharged out of the system through the exhaust channel without being circulated through the backwash channel. Can be easily transferred to Further, by providing the three-way valve, it is possible to easily perform an operation for switching between the filtration step and the backwashing step with a short cycle.

  According to the water treatment method and the water treatment system of the present invention, filtration and backwashing can be performed using a common decompression means, and the equipment can be simplified.

An example of the water treatment system of this invention is represented. The other example of the water treatment system of this invention is represented. The other example of the water treatment system of this invention is represented. The other example of the water treatment system of this invention is represented. The other example of the water treatment system of this invention is represented.

  The present invention relates to a water treatment method and a water treatment system using a filter medium, and more particularly to a water treatment method and a water treatment system capable of performing filtration with a filter medium and backwashing of the filter medium with a common decompression means.

  The water treatment method of the present invention has a filtration step and a backwashing step. In the filtration step, the water to be treated is introduced into a filtration module equipped with a filter medium to obtain filtered water. Although the to-be-processed water used as the process target in this invention is not specifically limited, Since solid-liquid separation is performed with a filter medium, it is preferable that solid content is contained. The treated water used in the present invention includes sewage, human waste, process wastewater generated by sewage treatment and human waste treatment, factory wastewater generated from food factories, paper pulp factories, chemical factories, etc., livestock manure, livestock manure, etc. Examples include wastewater generated by the treatment of livestock waste, kitchen wastewater, and sludge generated by these treatments.

  The filtration module is provided with a filter medium, and filtered water is obtained by introducing the water to be treated into the filtration module and filtering it with the filter medium. The filtration module has a supply side where treated water exists and a filtered water extraction side where filtered water exists, with the filter medium interposed therebetween, and filtrated water is taken out from the filtered water extraction side of the filtration module.

  Any filter medium may be used as long as it can capture suspended substances contained in the water to be treated and obtain filtered water. For example, a membrane filter medium can be used. The filter medium may be a so-called microfiltration membrane (MF membrane) or ultrafiltration membrane (UF membrane). The shape of the filter medium is not particularly limited, such as a tubular shape or a flat plate shape. The material which comprises a filter medium is not specifically limited, A synthetic resin, a ceramic, a metal, etc. are mentioned.

  For example, the filtration module is provided by immersing it in water to be treated held in a filtration tank. In this case, the filter medium is immersed in the treated water in the filtration tank, and the treated water in the filtration tank is filtered by the filter medium. Alternatively, the filtration module may be configured with a filter medium installed in the housing. In this case, the water to be treated is filtered by installing the filtration module outside the water tank holding the water to be treated and supplying the water to be treated into the filtration module.

  Filtration with a filter medium is performed using a differential pressure between the filter medium supply side and the filtrate extraction side. At this time, in the water treatment method of the present invention, the filtration with the filter medium is promoted by depressurizing the gas phase portion in contact with the filtrate discharged from the filtrate extraction side of the filtration module by the decompression means. Here, the filtrate discharged | emitted from the filtrate extraction side of the filtration module means the filtrate which exists continuously from the filtrate extraction side of a filtration module. By depressurizing the gas phase part in contact with the filtered water discharged from the filtrate extraction side of the filtration module by the decompression means, the pressure of the gas phase part can be reduced to near vacuum, and as a result, the supply side of the filter medium and The differential pressure between the filtrate water extraction sides is increased, and the water to be treated can be efficiently filtered. When the filtration module is immersed in the water to be treated, filtration is also promoted by the water pressure based on the depth of the filter medium, and when the filter medium is installed in the housing, the treatment to be supplied into the housing is performed. Filtration is also promoted by the water pressure.

  The depressurization means is not particularly limited as long as it can depressurize the gas phase portion in contact with the filtered water discharged from the filtrate extraction side of the filtration module, but the gas phase portion is depressurized by sucking the gas in the gas phase portion. It is preferable that it is a thing, and it is preferable that it is a mechanical pressure reduction means. In this case, the decompression means has a suction side and a discharge side. In the decompression means, gas is sucked from the suction side and taken into the decompression means, and the sucked gas is discharged from the discharge side. As the decompression means, a decompression pump (vacuum pump), a blower or the like can be used.

  The decompression means is preferably installed as follows. That is, a filtrate water flow path is provided which communicates with the filtrate water extraction side of the filtration module, and has a gas phase portion in contact with the filtrate water discharged from the filtrate water extraction side and the filtrate water. A suction channel is provided in communication with the gas phase portion. The pressure reducing means is preferably provided so that the suction side of the pressure reducing means communicates with the suction flow path. By providing the pressure reducing means in this way, the gas phase portion of the filtrate channel can be decompressed by sucking the gas in the gas phase portion of the filtrate channel.

  In the filtered water channel, it is preferable that the gas phase part is formed as a closed space except for a portion where the suction channel communicates so that the gas phase part can be depressurized by the depressurization means. For example, the filtered water flow path may be constituted only by a pipe line, or may be constituted by a tank provided in the pipe line. By providing a tank in the filtrate channel, it is easy to form a gas phase part of the filtrate channel in the tank. In this case, the filtered water flows into the tank, but the filtered water may be temporarily stored in the tank, or the filtered water may flow out immediately without being stored in the tank. If the filtered water flow path is composed of only pipes, the filtered water flow path can be created by providing a relatively large-diameter pipe or extending the pipe diagonally downward so that the filtered water naturally flows down. A gas phase part can be formed.

  It is preferable that the filtrate flow path is provided with a filtrate water tank in which filtrate water is present and a gas phase portion is provided in the upper part. If a filtrate water tank is provided in the filtrate water flow path, it becomes difficult to accidentally suck filtrate water by the decompression means, and the pressure in the gas phase part can be easily adjusted. When a filtrate water tank is provided in the filtrate water flow path, it is preferable to promote filtration of the filter medium by reducing the pressure of the gas phase portion of the filtrate water tank with a decompression means in the filtration step.

  The suction channel is provided in communication with the gas phase part of the filtrate channel and the suction side of the decompression means. The suction flow path may be provided connected to a pipe line constituting the filtrate water flow path, or may be provided connected to a tank constituting the filtrate water flow path. The suction flow path is preferably provided by connecting to a portion where the gas phase portion is stably present in the filtrate flow path. When the filtrate water flow path is equipped with a tank, the tank (specifically, the inside of the tank) It is preferable to be connected to the gas phase part.

  An exhaust passage is provided in communication with the discharge side of the decompression means. The gas discharged from the decompression means is transferred through the exhaust passage. The gas discharged from the decompression means is, for example, discharged outside the system or stored in a gas holder. In the latter case, the gas holder may be provided in communication with the exhaust passage. Further, the gas discharged from the decompression means may be discharged into a water tank such as a filtration tank and used for gas stirring in the water tank. In this case, the exhaust passage may be provided in communication with a gas agitating device.

  On the other hand, in the backwashing process, the gas discharged from the decompression means is supplied to the filtered water extraction side of the filtration module to wash the filter medium. For this purpose, a backwash channel is provided in communication with the exhaust channel and the filtered water extraction side of the filtration module. That is, in the backwashing process, the gas discharged from the decompression means (backwashing gas) is supplied into the filtration module through the backwashing passage, and the backwashing gas is permeated from the filtrate take-out side to the supply side. Let the filter media wash. In the water treatment method of the present invention, the filtration step and the backwashing step are performed using the common decompression means as described above, thereby eliminating the need for providing a blower or a compressor dedicated to backwashing, and simplifying the equipment. Can be achieved.

  The backwash channel may be directly connected to the filtrate extraction side of the filtration module, or may be connected to the filtrate channel. In any case, the gas discharged from the decompression means may be introduced to the filtrate extraction side of the filtration module. For this purpose, exhaust control means for controlling the flow of the gas discharged from the decompression means to the backwash flow path is provided.

  As the exhaust control means, an open / close device that opens and closes the flow path may be provided in each flow path as appropriate. A valve may be used as the opening / closing device. As the exhaust control means, it is preferable to provide an opening / closing device at least in the backwash channel, and the gas flow in the backwash channel is stopped in the filtration process by the switchgear, and the backwash channel is used for backwashing in the backwash process. It is preferable to allow gas to flow. Further, an opening / closing device for opening and closing the flow path may be provided downstream of the connection point of the exhaust flow path with the backwash flow path, and the downstream side of the connection point of the filtrate water flow path with the backwash flow path ( An opening / closing device that opens and closes the flow path may be provided when a connection point exists. By appropriately operating these switchgears, the gas discharged from the decompression means can be efficiently supplied to the filtrate extraction side of the filtration module.

  As the exhaust control means, it is also preferable to provide a three-way valve connected to the exhaust flow path at one end of the backwash flow path. By providing a three-way valve at the connection point between the discharge path and the backwash flow path, the gas discharged from the decompression means is circulated through the backwash flow path or through the exhaust flow path without being circulated through the backwash flow path. It can be easily discharged out of the system or transferred to a gas holder. Further, by providing the three-way valve, it is possible to easily perform an operation for switching between the filtration step and the backwashing step with a short cycle.

  The type of backwashing gas is not particularly limited, and may be appropriately determined according to the type of water to be treated. For convenience, the gas in the gas phase portion of the filtered water flow path may be used as the backwash gas, but if the air outside the gas phase portion is used, the gas phase portion can be reduced in size. In the case where the water to be treated has reactivity with air or changes in quality by being in contact with air, it is preferable to use an inert gas for the water to be treated as the backwash gas. Moreover, when it is calculated | required that to-be-processed water maintains an anaerobic state, it is preferable to use nitrogen gas and biogas as backwashing gas.

  In order to be able to supply the desired backwash gas, it is preferable that an air supply channel is provided in communication with at least one of the gas phase portions of the suction channel and the filtrate channel. One side of the air supply channel is provided so as to communicate with at least one of the gas phase part of the suction channel and the filtrate channel, but the other side of the air supply channel may be open to the atmosphere or communicate with the gas holder. You may do it. The other side of the air supply channel is appropriately determined according to the type of backwash gas.

  The air supply channel is preferably provided with an opening / closing device for opening and closing the channel. By opening the opening / closing device and allowing the gas to flow through the air supply passage in the backwashing step, the backwashing gas can be supplied to the suction side of the decompression means through the air supply passage. Moreover, you may provide the three-way valve connected to the gaseous-phase part of a suction flow path or a filtrate flow path at one end of an air supply flow path. In the filtration step, it is preferable to prevent gas from flowing into the air supply flow path by operating an opening / closing device provided in the air supply flow path.

  In the case where the filtration module is provided by being immersed in the water to be treated held in the filtration tank, the air supply flow path includes at least one of the gas phase part of the suction flow path and the filtrate water flow path and the gas phase part of the filtration tank. And may be provided in communication with each other. In this case, since the gas for backwashing is taken out from the gas phase part of the filtration tank and supplied to the filtration module provided in the filtration tank, the atmospheric pressure in the filtration tank is maintained in a substantially steady state, It becomes easy to perform processing stably. Moreover, since the gas phase part gas of the filtration tank is used as the backwashing gas, there is no need to worry that the backwashing gas adversely affects the water to be treated.

  In the water treatment method of the present invention, it is preferable to repeat the filtration step and the backwashing step in a state where the gas phase portion of the filtrate flow path is decompressed. That is, it is preferable to repeat the filtration step and the backwashing step in a state where the gas phase portion of the filtrate flow path is maintained at a negative pressure. Even in the backwashing process, by maintaining the gas phase part of the filtrate water flow path at a negative pressure, when the filtration process is performed after the backwashing process, the filtration with the filter medium can be performed immediately. Accordingly, the air supply channel is preferably connected to the suction channel, and an opening / closing device is appropriately provided so that the gas phase portion of the filtrate channel is blocked from the suction channel in the backwashing step. preferable. For example, a three-way valve connected to the suction flow path is provided at one end of the air supply flow path, or the flow path is connected to the suction flow path between the connection point of the suction flow path to the air supply flow path and the gas phase portion of the filtrate water flow path. An opening / closing device for opening and closing the road may be provided.

  In the water treatment method of the present invention, the filtration step and the backwashing step may be repeated while the decompression means is operating. In this invention, since a filtration process and a backwashing process can be performed by a common pressure reduction means, it is not necessary to stop the operation of the pressure reduction means every time the filtration process and the backwashing process are switched. Therefore, each process can be smoothly performed even when the filtration process and the backwashing process are switched, and the filtration process and the backwashing process can be frequently switched in a short cycle. Furthermore, it is not necessary to frequently turn on and off the decompression means, and the life of the decompression means can be expected to be extended.

  In the present invention, in order to increase the recovery rate of the filtrate obtained in the filtration step, a first opening and a second opening are provided on the filtrate extraction side of the filtration module, and a filtrate flow path is provided in communication with the first opening. It is preferable to provide a backwash channel in communication with the second channel. In this case, filtered water is obtained from the first opening in the filtration step, and in the backwashing step, the gas discharged from the decompression means (backwashing gas) is supplied to the filtered water extraction side through the second opening. Thus, the recovery rate of filtrate can be raised by providing the 1st opening and the 2nd opening in the filtrate extraction side of a filtration module. That is, when the backwashing gas is supplied into the filtration module from the second opening in the backwashing process, the filtered water remaining on the filtrate extraction side of the filtration module is discharged from the filtration module through the first opening, The recovery rate can be increased.

  The filtered water channel is preferably provided with an opening / closing device for opening and closing the channel. In this case, in the filtration process, the filtered water channel opening / closing device is opened to transfer the filtered water, and in the backwashing process, when the backwashing gas is supplied to the filtered water extraction side through the second opening, the filtered water channel is opened and closed. The device is preferably opened after a predetermined time and then closed. In the backwashing process, by opening the open / close device of the filtrate flow path while supplying the backwashing gas to the filtrate extraction side through the second opening, the filtration remaining on the filtrate extraction side of the filtration module in the filtration process Water can be drained from within the filtration module through the first opening. Then, in anticipation of the time when the filtered water can be discharged from the filtration module, the backwashing switch is closed while the backwashing gas is supplied to the filtered water extraction side through the second opening. The filter medium can be washed by permeating the working gas from the filtrate take-out side of the filter medium to the supply side.

  In the backwashing process, when opening and closing the open / close device of the filtrate flow path for a predetermined time and then closing it, the timing of closing the open / close device from the open state is the time during which filtered water can be almost discharged from the filtration module through the first opening. Is obtained from calculation or experiment, and may be appropriately determined based on the result.

  In the water treatment method of the present invention, it is also preferable to use an anaerobic treatment liquid containing biogas as the water to be treated. In this case, the water treatment system of the present invention is for treating an anaerobic treatment liquid containing biogas. The anaerobic treatment liquid is not particularly limited as long as it is obtained by anaerobic treatment of a liquid (including slurry) containing an organic substance or a solid. The anaerobic treatment is not limited as long as the organic matter undergoes methane fermentation by placing the liquid or solid matter containing the organic matter in an anaerobic state. Therefore, the anaerobic treatment solution includes methane gas or carbonic acid as a methane fermentation product. Biogas such as gas is included, and some are dissolved. In addition, the biogas should just contain methane gas at least.

  The anaerobic treatment liquid may be one in which methane fermentation has been completed or may be in the middle of methane fermentation. Methane fermentation may be performed in equipment intended to perform methane fermentation, such as a digester (methane fermenter), and liquids and solids containing organic substances are placed in an anaerobic state during transportation and storage. It may be caused by being.

  When an anaerobic treatment liquid is used as the water to be treated, it is preferable that the filtrate flow path is provided with a filtrate water tank, and the filtrate water tank preferably has a filtrate portion and a gas phase portion at the top. . Further, it is preferable to provide a gas holder in communication with the exhaust passage. In this case, in the filtration step, the gas phase portion of the filtrate water tank is decompressed by the decompression means, so that filtration with the filter medium is promoted and the filtrate water in the filtrate water tank is degassed. At this time, the filtered water is obtained from the anaerobic treatment liquid, so that the biogas dissolved in the filtered water is removed from the filtered water tank by degassing the filtered water in the filtration tank. The gas phase is transferred to the gas holder through the suction channel and the exhaust channel by the decompression means. Thus, the biogas collected by the gas holder can be used as an energy source. For example, energy may be recovered by supplying it to a gas turbine and burning it, or methane contained in biogas may be used as fuel for the fuel cell. Of course, you may just burn and use heat.

  When the water to be treated is an anaerobic treatment liquid containing biogas, it is preferable to use biogas generated from the anaerobic treatment liquid as the gas discharged from the decompression means in the backwashing step. In this case, it is preferable that the gas holder is provided in communication with the exhaust flow path, and the air supply flow path is provided in communication with at least one of the gas phase portion of the suction flow path and the filtrate flow path and the gas holder. By providing the air supply channel in this way, the biogas stored in the gas holder can be used as the backwash gas.

  In addition, when the filtration module is provided by immersing it in an anaerobic treatment liquid (treated water) held in a filtration tank, the air supply channel is connected to at least one of the gas phase part of the suction channel and the filtrate channel and the filtration tank. It may be provided in communication with the gas phase portion. In this case, the biogas present in the gas phase portion of the filtration tank can be used as the backwash gas. The biogas present in the gas phase part of the filtration tank is transferred to the gas holder through the flow path by providing a separate filtration tank exhaust flow path in communication with the gas phase part of the filtration tank and the gas holder. It may be recovered.

  When the filtration module is provided by immersing it in an anaerobic treatment liquid held in a filtration tank, the filtration tank may perform only filtration or may perform anaerobic treatment along with filtration. In the former case, for example, a filtration tank may be provided in communication with the digestion tank. In the latter case, for example, the filtration module is provided by being immersed in a digestion tank, or the filtration module is provided by being immersed in a receiving tank for sewage and human waste. In this case, the digestion tank and the receiving tank are regarded as a filtration tank.

  Next, configuration examples of the water treatment method and the water treatment system of the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments shown in the drawings.

  FIG. 1 shows a first embodiment of the water treatment system of the present invention. The water treatment system shown in FIG. 1 includes a filtration module 11, a filtrate water channel 21 provided in communication with the filtrate water extraction side 12 of the filtration module 11, and a decompression unit that decompresses the gas phase portion of the filtrate water channel 21. 31. In FIG. 1, a blower is used as the decompression means 31.

  The filtration module 11 includes a filter medium, and is provided by being immersed in the water to be treated 1 held in the filtration tank 14. The filtration module 11 has a supply side where the treated water 1 exists and a filtrate water extraction side 12 where the filtrate 2 exists, with the filter medium interposed therebetween.

  The filtrate channel 21 is provided with a gas-liquid separation tank 22, and the gas-liquid separation tank 22 constitutes a part of the filtrate channel 21. The filtered water flow path 21 has the filtered water 2 discharged from the filtered water extraction side 12, and has a gas phase part 3 in contact with the filtered water 2. The filtrate introduced into the gas-liquid separation tank 22 is discharged from the gas-liquid separation tank 22 through the filtrate collection channel 25 provided at the lower part of the gas-liquid separation tank 22, and the filtrate is collected. In FIG. 1, the air-liquid separation tank 22 is kept airtight by sealing the filtered water recovery flow path 25 with a water sealing portion 26.

  The decompression means 31 has a suction side and a discharge side, and a suction passage 32 is provided in communication with the suction side of the decompression means 31 and the gas phase portion 3 of the filtrate water passage 21. On the other hand, an exhaust passage 36 is provided in communication with the discharge side of the decompression means 31. A backwash channel 41 is provided in communication with the exhaust channel 36 and the filtrate extraction side 12 of the filtration module 11. In FIG. 1, the backwash channel 41 is connected to the filtrate channel 21, thereby communicating with the filtrate extraction side 12 of the filtration module 11.

  In the filtration step, the pressure reduction means 31 depressurizes the gas phase portion 3 in contact with the filtrate 2 discharged from the filtrate extraction side 12 of the filtration module 11, thereby promoting filtration with the filter medium of the filtration module 11. On the other hand, in the backwashing process, the gas 4 discharged from the decompression means 31 is supplied to the filtrate extraction side 12 of the filtration module 11 via the backwashing channel 41 to backwash the filter medium of the filtration module 11. That is, in the water treatment system shown in FIG. 1, the common decompression means 31 can suck the filtered water in the filtration step and supply the backwash gas in the backwash step. Moreover, a filtration process and a backwashing process can be repeated with the decompression means 31 operating.

  In the water treatment system of the present invention, in order to switch from the filtration process to the backwashing process (or from the backwashing process to the filtration process), the flow of the gas 4 discharged from the decompression means 31 to the backwashing channel 41 is controlled. Exhaust control means is provided. In FIG. 1, an opening / closing device (two-way valve) 42 for opening and closing the flow path is provided in the backwash channel 41, and the opening / closing device (two-way valve) is disposed downstream of the connection point of the exhaust flow channel 36 with the backwash channel 41. 37) 37). In the water treatment system shown in FIG. 1, an opening / closing device 42 and an opening / closing device 37 are provided as exhaust control means. In the filtration process, the opening / closing device 42 is closed, the opening / closing device 37 is opened, and in the backwashing process, the opening / closing device 42 is opened. The opening / closing device 37 is operated to close.

  In the water treatment system shown in FIG. 1, an air supply passage 33 is provided in communication with the gas phase portion 3 of the filtered water passage 21 (gas-liquid separation tank 22), and the air supply passage 33 is opened and closed. An opening / closing device (two-way valve) 34 is provided. One side of the air supply channel 33 communicates with the gas phase part 3 of the filtrate channel 21 and the other side is open to the atmosphere. By operating the opening / closing device 34 to be closed in the filtration step and opening the opening / closing device 34 in the backwashing step, air can be supplied to the suction side of the decompression means 31 through the air supply passage 33 as the backwashing gas. .

  The filtered water channel 21 is preferably provided with an opening / closing device (two-way valve) 24 for opening and closing the channel. By opening and closing the switch 24 in the filtration process and closing the switch 24 in the backwashing process, the backwashing gas is suitably supplied to the filtered water extraction side 12 of the filtration module 11 in the backwashing process. Will be able to.

  FIG. 2 shows a second embodiment of the water treatment system of the present invention. The water treatment system according to the second embodiment is provided with a first opening and a second opening on the filtrate outlet side of the filtration module, and a filtered water discharge channel in communication with the second opening. Is different from the water treatment system of the first embodiment in that it is provided in communication with the suction channel. In the following description, the description of the same part as the description of the first embodiment is omitted.

  In the water treatment system shown in FIG. 2, a first opening 13 and a second opening 14 are provided on the filtrate extraction side 12 of the filtration module 11. A filtered water passage 21 is provided in communication with the first opening 13, and a filtered water discharge passage 45 is provided in communication with the second opening 14. The filtered water discharge channel 45 is provided with an opening / closing device (two-way valve) 46 for opening and closing the channel. In the filtration process, the switch 46 is closed, and in the backwash process, the switch 46 is opened and then closed. In detail, when supplying the gas 4 discharged from the decompression means 31 to the filtered water extraction side 12 of the filtration module 11 through the first opening 13 in the backwashing process, the opening / closing device 46 is opened for a predetermined time and then closed. To operate. By opening the switch 46 for a predetermined time from the start of the backwashing process, the filtrate remaining on the filtrate extraction side 12 and the filtrate passage 21 of the filtration module 11 is collected through the filtrate drain passage 45. Is possible. And after collect | recovering filtered water, the switch 46 may be closed and the filter medium of the filtration module 11 should just be backwashed with the gas for backwashing. By operating the opening / closing device 46 in this manner, the filtered water obtained in the filtration step can be efficiently recovered without being returned to the supply side of the filter medium wastefully in the backwashing step.

  In the water treatment system shown in FIG. 2, the air supply channel 33 is provided in communication with the suction channel 32. The air supply channel 33 may be provided in communication with the suction channel 32 as described above. In this case, the backwash gas can be supplied to the suction side of the decompression means 31 through the air supply channel 33.

  FIG. 3 shows a third embodiment of the water treatment system of the present invention. In the water treatment system of the third embodiment, a first opening and a second opening are provided on the filtrate extraction side of the filtration module, a filtrate water flow path is provided in communication with the first opening, and backwashing is performed in communication with the second opening. In terms of providing a flow path, providing a filtrate water tank instead of providing a gas-liquid separation tank in the filtrate water flow path, and providing a three-way valve in the backwash flow path as an exhaust control means. Different from the water treatment system of one embodiment. In the following description, the description of the same part as the description of the first embodiment is omitted.

  In the water treatment system shown in FIG. 3, a first opening 13 and a second opening 14 are provided on the filtrate extraction side 12 of the filtration module 11. A filtered water flow path 21 is provided in communication with the first opening 13, and a backwash flow path 41 is provided in communication with the second opening 14. In the filtration step, filtrate water is obtained from the first opening 13, and in the backwashing step, the gas 4 discharged from the decompression means 31 is supplied to the filtrate water extraction side 12 through the second opening 14. By connecting the filtrate flow path 21 and the backwash flow path 41 to the filtration module 11 in this way, when the backwashing gas is supplied from the second opening 14 in the backwashing process, the filtered water extraction side 12 of the filtration module 11 is supplied. The remaining filtered water can be discharged from the filtration module 11 through the first opening 13 and collected.

  In the water treatment system shown in FIG. 3, the open / close device 24 of the filtered water passage 21 is opened in the filtration step, and the filtered water 2 is transferred through the filtered water passage 21. On the other hand, in the backwashing process, when supplying the backwashing gas to the filtered water extraction side 12 of the filtration module 11 through the second opening 14, it is preferable to operate the opening / closing device 24 so that it is closed after being opened for a predetermined time. Thus, by operating the opening / closing device 24 of the filtrate flow path 21 in the backwash process, the filtrate remaining on the filtrate extraction side 12 of the filtration module 11 can be efficiently recovered, and the filtration module 11 It becomes easy to perform backwashing of a filter medium suitably.

  In the water treatment system shown in FIG. 3, the filtrate water flow path 21 has a filtrate water tank 23 in which the filtrate water 2 ′ is present and the gas phase part 3 is provided in the upper part. A filtered water recovery passage 25 having a water seal portion 26 is connected to the side surface of the filtered water tank 23, thereby ensuring the level of the filtered water 2 ′ in the filtered water tank 23, and the filtered water tank 23. Airtightness is maintained. On the other hand, a suction flow path 32 communicates with the gas phase portion 3 of the filtrate water tank 23, and the gas phase portion 3 of the filtrate water tank 23 is decompressed by the decompression means 31. In FIG. 3, the pipeline portion of the filtrate channel 21 is connected to the gas phase portion 3 of the filtrate tank 23, but the filtrate portion 2 ′ of the filtrate tank 23 exists in the pipeline portion of the filtrate channel 21. You may connect to the part to do.

  In the water treatment system shown in FIG. 3, as an exhaust control means, a three-way valve 43 is provided at one end of the backwash channel 41 in connection with the exhaust channel 36. The three-way valve 43 replaces the opening / closing devices (two-way valves) 37 and 42 in the water treatment system shown in FIG. 1 with one, and the system through the exhaust passage 36 for the gas 4 discharged from the decompression means 31. The outer discharge and the flow to the backwash channel 41 are controlled. By providing the three-way valve 43, a filtration process and a backwashing process can be switched easily.

  FIG. 4 shows a fourth embodiment of the water treatment system of the present invention. The water treatment system according to the fourth embodiment is the third embodiment in that the gas holder is provided in communication with the exhaust flow path, and the air supply flow path is provided in communication with the suction flow path and the gas holder. Different from the water treatment system of the embodiment. In the following description, the description of the part overlapping with the description of the third embodiment is omitted.

  In the water treatment system shown in FIG. 4, a gas holder 38 is provided in communication with the exhaust passage 36. That is, the exhaust passage 36 has one side communicating with the discharge side of the decompression means 31 and the other side communicating with the gas holder 38. By providing the gas holder 38 in this way, the gas 4 discharged from the decompression means 31 can be stored in the gas holder 38. The water treatment system shown in FIG. 4 is effective when, for example, an anaerobic treatment liquid containing biogas is used as the water to be treated, and the biogas contained in the water 1 is treated in the filtered water tank 23. The biogas can be stored in the gas holder 38 by moving to the gas phase section 3 and sucking with the decompression means 31.

  In the water treatment system shown in FIG. 4, the air supply channel 33 is provided in communication with the suction channel 32 and the gas holder 38. If the supply air flow path 33 is connected in this way, the gas stored in the gas holder 38 can be used as the backwash gas. For example, when the water 1 to be treated is an anaerobic treatment liquid, the biogas stored in the gas holder 38 is used as a backwash gas, so that the anaerobic treatment liquid held in the filtration tank 14 is favored. Vaporization can be suppressed.

  In the water treatment system shown in FIG. 4, a three-way valve 35 is provided at the connection point between the air supply channel 33 and the suction channel 32. That is, a three-way valve 35 is provided at one end of the air supply channel 33 so as to be connected to the suction channel 32. The three-way valve 35 replaces the opening / closing device (two-way valve) 34 provided in the air supply passage 33 in FIG. In addition, by providing the three-way valve 35 at the connection point between the air supply channel 33 and the suction channel 32 as described above, the gas phase portion 3 can be maintained in a reduced pressure state in the backwashing process. That is, by operating the three-way valve 35 so that the gas flows from the air supply passage 33 to the decompression means 31, the gas phase portion 3 is sealed and maintained at a negative pressure. Therefore, when the filtration step is performed after the back washing step (that is, when the three-way valve 35 is operated so that gas flows from the gas phase portion 3 to the decompression means 31), the filtration with the filter medium is performed immediately. be able to.

  FIG. 5 shows a fifth embodiment of the water treatment system of the present invention. The water treatment system according to the fifth embodiment is provided with a filtered water channel in communication with the second opening of the filtration module and a backwash channel, and a gas holder provided in communication with the exhaust channel. The water supply system differs from the water treatment system of the third embodiment in that an air supply channel is provided in communication with the suction channel and the gas phase part of the filtration tank. In the following description, the description of the part overlapping with the description of the third embodiment is omitted.

  In the water treatment system shown in FIG. 5, a filtered water flow path 21 a is provided in communication with the first opening 13 of the filtration module 11, while the filtered water flow is provided in the second opening 14 of the filtration module 11 together with the backwash flow path 41. A path 21b is provided in communication. The filtrate channels 21a and 21b are provided with opening / closing devices (two-way valves) 24a and 24b for opening and closing the channels, respectively. However, the opening / closing device 24b is provided on the downstream side (the side far from the filtration module 11) from the connection point between the filtered water channel 21b and the backwash channel 41. The water treatment system shown in FIG. 5 can be regarded as a system in which the water treatment system shown in FIG. 1 and the water treatment system shown in FIG. 3 are combined. In this case also, the water treatment method of the present invention is suitable. Can be implemented.

  In the water treatment system shown in FIG. 5, a gas holder 38 is provided in communication with the exhaust passage 36 as in the water treatment system shown in FIG. 4, but the air supply passage 33 is connected to the suction passage 32. It is provided in communication with the gas phase part 15 of the filtration tank 14. The water treatment system shown in FIG. 5 can also be suitably applied when the water to be treated 1 is an anaerobic treatment liquid, and by using the gas in the gas phase portion 15 of the filtration tank 14 as the backwash gas, The aerobic treatment of the anaerobic treatment liquid held in the filtration tank 14 can be suppressed. In FIG. 5, the air supply flow path 33 is connected to the suction flow path 32, but the air supply flow path 33 may be connected to the gas phase part 3 of the filtrate water flow path 21.

  The present invention is caused by processing of livestock waste such as sewage, human waste, process wastewater generated from sewage treatment and human waste processing, factory wastewater generated from food factories, pulp and paper factories, chemical factories, etc. It can be used for the treatment of wastewater, kitchen wastewater, and sludge generated by these treatments.

1: Water to be treated 2, 2 ': Filtered water 3: Gas phase part 4: Gas discharged from the decompression means (backwash gas)
DESCRIPTION OF SYMBOLS 11: Filtration module 12: Filtrated water extraction side 13: 1st opening 14: 2nd opening 21,21a, 21b: Filtration water flow path 22: Gas-liquid separation tank 23: Filtration water tank 31: Pressure reduction means 32: Suction flow path 33 : Air supply flow path 35, 43: Three-way valve 36: Exhaust flow path 38: Gas holder 41: Backwash flow path

Claims (15)

A filtration step of introducing treated water into a filtration module equipped with a filter medium to obtain filtered water;
A water treatment method comprising a backwashing step of washing the filter medium,
In the filtration step, by the pressure reducing means, by depressurizing the gas phase part in contact with the filtered water discharged from the filtered water extraction side of the filtration module, the filtration with the filter medium is promoted,
In the backwashing step, the gas discharged from the decompression means is supplied to the filtered water extraction side of the filtration module to wash the filter medium. The filtration module is provided with a first opening and a second opening on the filtrate extraction side,
In the filtration step, filtered water is obtained from the first opening,
2. The water treatment method according to claim 1, wherein in the backwashing step, the gas discharged from the decompression unit is supplied to the filtered water extraction side through the second opening. A filtered water flow path is provided in communication with the first opening,
The filtered water flow path is provided with an opening / closing device for opening and closing the flow path,
In the filtration step, the switch is opened to transfer filtered water,
The said backwash process WHEREIN: When supplying the gas discharged from the said pressure reduction means to the said filtered water extraction side through the said 2nd opening, it is made to close, after opening and closing the said opening / closing apparatus for a predetermined period. Water treatment method. In communication with the filtrate extraction side of the filtration module, a filtrate flow path provided with a filtrate tank is provided,
The filtrate water tank is provided with a filtrate and a gas phase portion at the top,
In the said filtration process, the water treatment method as described in any one of Claims 1-3 which promotes filtration of the said filter medium by decompressing the gaseous-phase part of the said filtrate water tank with the said pressure reduction means.   The water treatment method as described in any one of Claims 1-4 which repeats the said filtration process and the said backwashing process in the state which pressure-reduced the said gaseous-phase part.   The water treatment method according to any one of claims 1 to 5, wherein the filtration step and the backwash step are repeated while the decompression unit is operated. The water to be treated is an anaerobic treatment liquid containing biogas;
The water treatment method according to any one of claims 1 to 6, wherein in the backwashing step, biogas generated from the anaerobic treatment liquid is used as the gas discharged from the decompression unit. A filtration module comprising a filter medium, and having a supply side on which the treated water exists and a filtrate water extraction side on which filtered water exists, across the filter medium,
Communicating with the filtered water outlet side, filtered water discharged from the filtered water outlet side, and a filtered water flow path having a gas phase portion in contact with the filtered water,
A depressurization means having a suction side and a discharge side, and depressurizing the gas phase part of the filtrate water flow path;
A suction channel provided in communication with the gas phase portion of the filtrate channel and the suction side of the decompression means;
An exhaust passage provided in communication with the discharge side of the decompression means;
A backwash flow path provided in communication with the exhaust flow path and the filtrate extraction side of the filtration module;
A water treatment system comprising exhaust control means for controlling the flow of the gas discharged from the decompression means to the backwash channel.   The water treatment system according to claim 8, wherein the filtered water channel is provided with an opening / closing device that opens and closes the channel. The filtration module is provided with a first opening and a second opening on the filtrate extraction side,
The filtered water flow path communicates with the first opening;
The water treatment system according to claim 8 or 9, wherein the backwash channel is in communication with the second opening.   The water treatment system according to any one of claims 8 to 10, wherein the filtrate water flow path has a filtrate water tank in which filtrate water is present and a gas phase part is provided at an upper part. An air supply channel is provided in communication with at least one of the gas phase part of the suction channel and the filtrate channel,
The water treatment system according to any one of claims 8 to 11, wherein the air supply channel is provided with an opening / closing device that opens and closes the channel. A gas holder is provided in communication with the exhaust flow path;
The water treatment system according to claim 12, wherein the air supply channel communicates with at least one of a gas phase part of the suction channel and the filtered water channel and the gas holder. The filtration module is provided by being immersed in water to be treated held in a filtration tank,
The water treatment system according to claim 12 or 13, wherein the air supply channel communicates with at least one of the suction channel and the gas phase part of the filtered water channel and the gas phase part of the filtration tank.   The water treatment system according to any one of claims 8 to 14, wherein the exhaust control unit is a three-way valve provided at one end of the backwash channel and connected to the exhaust channel.

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