CN116710193A - Filter membrane cleaning device, water treatment device, and filter membrane cleaning method - Google Patents
Filter membrane cleaning device, water treatment device, and filter membrane cleaning method Download PDFInfo
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- CN116710193A CN116710193A CN202180090940.2A CN202180090940A CN116710193A CN 116710193 A CN116710193 A CN 116710193A CN 202180090940 A CN202180090940 A CN 202180090940A CN 116710193 A CN116710193 A CN 116710193A
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- cleaning liquid
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- cleaning
- storage tank
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- 238000004140 cleaning Methods 0.000 title claims abstract description 362
- 239000012528 membrane Substances 0.000 title claims abstract description 173
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims description 105
- 238000000034 method Methods 0.000 title claims description 44
- 239000007788 liquid Substances 0.000 claims abstract description 297
- 238000001914 filtration Methods 0.000 claims abstract description 144
- 239000000126 substance Substances 0.000 claims abstract description 93
- 238000005374 membrane filtration Methods 0.000 claims description 59
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 claims description 51
- 238000000926 separation method Methods 0.000 claims description 21
- 230000007423 decrease Effects 0.000 abstract description 5
- 238000005259 measurement Methods 0.000 description 14
- 239000010802 sludge Substances 0.000 description 14
- 239000007789 gas Substances 0.000 description 10
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 9
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 9
- 239000003795 chemical substances by application Substances 0.000 description 7
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 6
- 239000010865 sewage Substances 0.000 description 6
- 239000005708 Sodium hypochlorite Substances 0.000 description 5
- 239000000356 contaminant Substances 0.000 description 5
- 239000003814 drug Substances 0.000 description 5
- 229940079593 drug Drugs 0.000 description 5
- 238000000605 extraction Methods 0.000 description 5
- 230000004907 flux Effects 0.000 description 5
- 230000014759 maintenance of location Effects 0.000 description 5
- -1 polyethylene Polymers 0.000 description 5
- 239000011148 porous material Substances 0.000 description 5
- SUKJFIGYRHOWBL-UHFFFAOYSA-N sodium hypochlorite Chemical compound [Na+].Cl[O-] SUKJFIGYRHOWBL-UHFFFAOYSA-N 0.000 description 5
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 4
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 4
- 238000001179 sorption measurement Methods 0.000 description 4
- 238000005406 washing Methods 0.000 description 4
- 238000007599 discharging Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 235000006408 oxalic acid Nutrition 0.000 description 3
- 238000011085 pressure filtration Methods 0.000 description 3
- 230000002035 prolonged effect Effects 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- 229920001780 ECTFE Polymers 0.000 description 2
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 2
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 2
- 239000002033 PVDF binder Substances 0.000 description 2
- 238000005273 aeration Methods 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 229920001577 copolymer Polymers 0.000 description 2
- 238000000354 decomposition reaction Methods 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 229920000840 ethylene tetrafluoroethylene copolymer Polymers 0.000 description 2
- 229910052731 fluorine Inorganic materials 0.000 description 2
- 239000011737 fluorine Substances 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 238000001471 micro-filtration Methods 0.000 description 2
- 229910017604 nitric acid Inorganic materials 0.000 description 2
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 2
- 239000004810 polytetrafluoroethylene Substances 0.000 description 2
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 238000000108 ultra-filtration Methods 0.000 description 2
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- 239000001856 Ethyl cellulose Substances 0.000 description 1
- ZZSNKZQZMQGXPY-UHFFFAOYSA-N Ethyl cellulose Chemical compound CCOCC1OC(OC)C(OCC)C(OCC)C1OC1C(O)C(O)C(OC)C(CO)O1 ZZSNKZQZMQGXPY-UHFFFAOYSA-N 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000011001 backwashing Methods 0.000 description 1
- 239000001913 cellulose Substances 0.000 description 1
- 229920002678 cellulose Polymers 0.000 description 1
- 229920002301 cellulose acetate Polymers 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000013043 chemical agent Substances 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 238000009295 crossflow filtration Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 229920001249 ethyl cellulose Polymers 0.000 description 1
- 235000019325 ethyl cellulose Nutrition 0.000 description 1
- 210000003608 fece Anatomy 0.000 description 1
- 238000011086 high cleaning Methods 0.000 description 1
- 239000003295 industrial effluent Substances 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000010907 mechanical stirring Methods 0.000 description 1
- 150000007522 mineralic acids Chemical class 0.000 description 1
- 150000007524 organic acids Chemical class 0.000 description 1
- 235000005985 organic acids Nutrition 0.000 description 1
- 239000007800 oxidant agent Substances 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 229920002493 poly(chlorotrifluoroethylene) Polymers 0.000 description 1
- 229920001748 polybutylene Polymers 0.000 description 1
- 239000005023 polychlorotrifluoroethylene (PCTFE) polymer Substances 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920000098 polyolefin Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 239000013535 sea water Substances 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D65/00—Accessories or auxiliary operations, in general, for separation processes or apparatus using semi-permeable membranes
- B01D65/02—Membrane cleaning or sterilisation ; Membrane regeneration
- B01D65/06—Membrane cleaning or sterilisation ; Membrane regeneration with special washing compositions
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
Landscapes
- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
Abstract
The filter membrane cleaning device comprises: a circulation flow path (25) that connects an outflow port (40) and an inflow port (41) of the cleaning liquid storage tank (27); and a supply channel (4) for supplying the circulated cleaning liquid (28) to the filtration membrane (3). The flow rate of the cleaning liquid (28) is set to be faster in the circulation flow path (25) than in the supply flow path (4). As a result, the decrease in the concentration of the chemical in the cleaning liquid (28) during the period in which the cleaning liquid (28) is supplied from the cleaning liquid storage tank (27) to the filtration membrane (3) can be suppressed, and therefore the concentration of the chemical in the cleaning liquid (28) can be maintained. In addition, since the supply flow rate is lower than the circulation flow rate, the amount of the cleaning liquid (28) used can be reduced.
Description
Technical Field
The present disclosure relates to a filtration membrane cleaning device, a water treatment device, and a filtration membrane cleaning method.
Background
As a method for separating and removing a dirty substance from water to be treated such as sewage (sewage) and factory wastewater, membrane filtration treatment using a filtration membrane is known. When the membrane filtration treatment is continued, the filtration performance gradually decreases because the contaminants adhere to the surface and pores of the filtration membrane and clog. Therefore, in order to maintain the filtration performance, the filtration membrane is cleaned using the cleaning liquid. In order to improve the cleaning effect, the cleaning liquid contains a chemical.
For example, the water treatment apparatus of patent document 1 uses a cleaning liquid containing ozone. Ozone has high cleaning power, but is easily decomposed. Therefore, ozone may be decomposed in the cleaning liquid remaining in the flow path for supplying the cleaning liquid to the filter membrane. In this case, the ozone-decomposed cleaning liquid is supplied to the filtration membrane in the initial stage of cleaning, and the cleaning efficiency may be deteriorated. Therefore, a circulation flow path is provided for returning the cleaning liquid in the flow path to the cleaning liquid storage tank, and the ozone-decomposed cleaning liquid remaining in the flow path is replaced with the ozone-containing cleaning liquid before cleaning.
Prior art literature
Patent literature
Patent document 1: japanese patent laid-open No. 2003-251160
Disclosure of Invention
Problems to be solved by the invention
For example, in the case of rebuilding a sewage treatment facility or a plant and introducing a water treatment apparatus, there is a case where a space into which the sewage treatment facility or the plant can be introduced is previously defined. In this case, the cleaning liquid storage tank cannot be provided in the vicinity of the membrane separation tank in which the membrane filtration process is performed, and there is a possibility that a flow path from the cleaning liquid storage tank to the membrane separation tank may be extended. In the conventional water treatment apparatus, when the flow path is long, the time required for supplying the cleaning liquid is prolonged. As a result, the chemical may be decomposed during the supply of the cleaning liquid, and the chemical may be supplied to the filtration membrane at a concentration lower than a predetermined concentration. Therefore, in order to supply the drug to the filtration membrane before the drug is decomposed, it is attempted to increase the supply flow rate. However, if the supply flow rate is increased, the amount of the cleaning liquid used increases.
The present disclosure has been made to solve the above-described problems, and an object of the present disclosure is to provide a cleaning device for a filtration membrane, which can maintain the concentration of a chemical in a cleaning liquid and reduce the amount of the cleaning liquid used.
Means for solving the problems
The present disclosure relates to a filter membrane cleaning device including: a cleaning liquid storage tank for storing a cleaning liquid containing a chemical for cleaning the filtration membrane, the cleaning liquid having an outflow port and an inflow port; a circulation flow path connecting the outflow port and the inflow port of the cleaning liquid storage tank, and provided with a circulation pump for circulating the cleaning liquid; a supply flow path connected to the circulation flow path and provided with a supply pump for supplying a part of the cleaning liquid circulated in the circulation flow path to the filtration membrane; and a control unit that controls at least one of the circulation pump and the supply pump so that the flow rate of the cleaning liquid is faster in the circulation flow path than in the supply flow path.
In addition, the water treatment apparatus according to the present disclosure includes: a membrane separation tank having a filtration membrane for performing membrane filtration treatment on water to be treated; a membrane filtration water tank for storing membrane filtration water treated by membrane filtration in a membrane separation tank; a cleaning liquid storage tank for storing a cleaning liquid containing a chemical for cleaning the filtration membrane, the cleaning liquid having an outflow port and an inflow port; a circulation flow path connecting the outflow port and the inflow port of the cleaning liquid storage tank, and provided with a circulation pump for circulating the cleaning liquid; a supply flow path connected to the circulation flow path and provided with a supply pump for supplying a part of the cleaning liquid circulated in the circulation flow path to the filtration membrane; and a control unit that controls at least one of the circulation pump and the supply pump so that the flow rate of the cleaning liquid is faster in the circulation flow path than in the supply flow path.
The method for cleaning a filtration membrane according to the present disclosure is characterized by circulating a cleaning solution in a circulation flow path connecting an outlet port and an inlet port of a cleaning solution storage tank in which the cleaning solution is stored; supplying a part of the cleaning liquid circulated in the circulation flow path to the filtration membrane via a supply flow path for supplying a part of the cleaning liquid circulated in the circulation flow path from the circulation flow path to the filtration membrane; the flow rate of the cleaning liquid is made faster in the circulation flow path than in the supply flow path.
Effects of the invention
According to the present disclosure, a cleaning device for a filtration membrane can be provided, which includes a circulation flow path connecting an outlet and an inlet of a cleaning liquid storage tank and a supply flow path for supplying the circulated cleaning liquid to the filtration membrane, and can maintain the chemical concentration of the cleaning liquid and reduce the amount of the cleaning liquid by making the flow rate of the cleaning liquid faster in the circulation flow path than in the supply flow path.
Drawings
Fig. 1 is a schematic view of a water treatment apparatus according to embodiment 1.
Fig. 2 is a schematic view of the water treatment apparatus according to embodiment 2.
Fig. 3 is a schematic view of the water treatment apparatus according to embodiment 3.
Fig. 4 is a schematic view of the water treatment apparatus according to embodiment 3.
Detailed Description
Embodiment 1.
A water treatment apparatus 100 including a cleaning apparatus for a filtration membrane 3 according to embodiment 1 will be described with reference to fig. 1. Fig. 1 is a schematic view of a water treatment apparatus 100. The water treatment device 100 includes: a membrane separation tank 2 having a filtration membrane 3 for performing membrane filtration treatment on the water 1 to be treated; a membrane filtration water tank 18 for storing the membrane filtration water 19 subjected to the membrane filtration treatment in the membrane separation tank 2; a cleaning liquid storage tank 27 for storing a cleaning liquid 28 for cleaning the filtration membrane 3; and a flow path for discharging the membrane-filtered water 19 subjected to the membrane filtration treatment by the filtration membrane 3 and supplying the cleaning liquid 28.
In the membrane separation tank 2, for example, a filtration membrane 3 is used to separate and remove a dirty substance from the water 1 treated by the activated sludge process. The water to be treated 1 is, for example, sewage, secondary treated water of sewage, industrial effluent, seawater, feces, etc., and flows into the membrane separation tank 2 through the water to be treated flow path 5. The membrane separation tank 2 may be connected to a sludge extraction channel 6 and a sludge circulation channel 7. The sludge extraction flow path 6 is provided with a sludge extraction pump 9 for extracting sludge, and the sludge circulation flow path 7 is provided with a sludge circulation pump 10 for circulating the sludge in the membrane separation tank 2. In addition, a gas dispersing device 8 may be disposed at the bottom of the membrane separation tank 2. The membrane surface aeration blower 12 is connected to the air diffusing device 8 via an air supply pipe 11.
The material of the filtration membrane 3 is not limited, but a fluorine-based resin compound having excellent resistance to a strong oxidizing agent such as ozone is preferable. For example, polyolefin such as polyethylene, polypropylene, and polybutylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-ethylene copolymer (ETFE), polytrifluoroethylene (PCTFE), chlorotrifluoroethylene-Ethylene Copolymer (ECTFE), polyvinylidene fluoride (PVDF), and fluorine-based resin compound such as Polytetrafluoroethylene (PTFE), cellulose such as cellulose acetate and ethylcellulose, ceramics, and the like can be used. In addition, 2 or more kinds of the above materials may be combined.
The type of the filtration membrane 3 is not limited. For example, various filtration membranes 3 known in the art, such as a Microfiltration (MF) membrane and an Ultrafiltration (UF) membrane, may be used.
The average pore diameter of the filtration membrane 3 is not limited, but is preferably 0.001 μm or more and 1 μm or less, more preferably 0.01 μm or more and 0.1 μm or less. By using the filtration membrane 3 having the average pore diameter in this range, not only the dirty substances adhering to the surface of the filtration membrane 3 in contact with the water to be treated 1 but also the dirty substances chemically adhering to the surface of the filtration membrane 3 or the pores of the filtration membrane 3 in contact with the membrane filtration water 19 can be effectively removed.
The shape of the filtration membrane 3 is not limited. For example, the shape may be a cylindrical shape, a flat film shape, or the like, which is well known in the art. In addition, a dipping type, a shell type, a monolith type, or the like can be used.
The water passing method of the filtration membrane 3 is not limited. For example, the filtration method may be a full-volume filtration method or a cross-flow filtration method. The external pressure filtration system may be an external pressure filtration system in which the water 1 to be treated flows outside the filtration membrane 3 and the filtered water flows inside the filtration membrane 3, or an internal pressure filtration system in which the water 1 to be treated flows inside the filtration membrane 3 and the filtered water flows outside the filtration membrane.
The membrane-filtered water 19 subjected to the membrane filtration treatment by the membrane separation tank 2 is stored in the membrane filtration water tank 18.
The water treatment apparatus 100 includes a cleaning apparatus for cleaning the filtration membrane 3. The cleaning device has a cleaning liquid storage tank 27 for storing a cleaning liquid 28 containing a chemical for cleaning the filtration membrane 3.
The type of the chemical is not limited as long as it does not deteriorate the material of the filtration membrane 3 and can decompose organic or inorganic substances. Thus, substances well known in the art may be used. Examples of the agent that decomposes the organic substance include sodium hypochlorite, hydrogen peroxide, sodium hydroxide, and ozone. They may be used alone or in combination of 2 or more. When 2 or more agents capable of decomposing an organic substance are used in combination, the standard redox potential (25 ℃) of the first agent measured using a hydrogen electrode is preferably less than 2.0V, and the standard redox potential (25 ℃) of the second agent measured using a hydrogen electrode is preferably 2.0V or more. For example, sodium hypochlorite may be used as the first agent and ozone may be used as the second agent. Examples of the substance capable of decomposing the inorganic substance include inorganic acids such as hydrochloric acid, sulfuric acid, and nitric acid, and organic acids such as oxalic acid and citric acid. These may be used alone or in combination of 2 or more. The substance capable of decomposing an organic substance and the substance capable of decomposing an inorganic substance may be used in combination of 2 or more kinds. In this case, any one of the first and second agents is not limited to be used. For example, in the case of using a substance capable of decomposing an organic substance as the first chemical, a substance capable of decomposing an inorganic substance is used as the second chemical. In the case of using a substance capable of decomposing an inorganic substance as the first chemical, a substance capable of decomposing an organic substance may be used as the second chemical.
The chemical concentration of the cleaning liquid 28 is not limited. For example, in the case of using a substance capable of decomposing an organic substance, sodium hypochlorite (effective chlorine concentration) is preferably 1.0g/L or more and 5.0g/L or less, and sodium hydroxide is preferably 1.0g/L or more and 4.0g/L or less. Ozone is preferably 10mg/L or more and 40mg/L or less, more preferably 20mg/L or more and 30mg/L or less. When a substance capable of decomposing an inorganic substance is used, hydrochloric acid, sulfuric acid, and nitric acid are preferably 1.0g/L or more and 10.0g/L or less, oxalic acid is preferably 1.0g/L or more and 2.0g/L or less, and citric acid is preferably 1g/L or more and 10g/L or less. If the concentration of the chemical is lower than the above range, the time required for decomposing the contaminants adhering to the filtration membrane 3 increases, and as the amount of the cleaning liquid 28 used increases, the capacity of the chemical tank increases. On the other hand, if the concentration of the drug is higher than the above range, the amount of the drug to be used increases, and thus the cost required for the drug increases.
The flow path is formed by, for example, a pipe. As shown in fig. 1, the flow paths include a circulation flow path 25, a supply flow path 4, and a membrane filtration water flow path 17. The circulation flow path 25 is a flow path for connecting the outflow port 40 of the cleaning liquid storage tank 27 to the inflow port 41 and circulating the cleaning liquid 28 stored in the cleaning liquid storage tank 27. The supply channel 4 is a channel for supplying the washing liquid 28 to the filtration membrane 3 of the membrane separation tank 2, and is a channel for supplying the membrane-filtered water 19 subjected to the membrane filtration treatment by the filtration membrane 3 to the membrane filtration water tank 18. The membrane filtration water channel 17 is a channel connecting the membrane filtration water tank 18 to the supply channel 4.
The switching unit 20 is provided in the supply channel 4, and connects the supply channel 4 to the membrane filtration water channel 17. The switching unit 21 is provided in the circulation flow path 25, and connects the circulation flow path 25 to the supply flow path 4.
The switching units 20 and 21 are, for example, three-way valves capable of switching the flow paths of the washing liquid 28 and the membrane-filtered water 19.
The circulation flow path 25 includes a circulation pump 22 and a circulation flow rate measurement unit 23. Further, the cleaning liquid concentration measuring section 24 may be included. The cleaning liquid 28 is returned to the cleaning liquid reservoir 27 through the circulation flow path 25 by the circulation pump 22. The circulation flow rate measuring unit 23 is not limited as long as it can measure the flow rate of the cleaning liquid 28 circulated through the circulation flow path 25. For example, an electromagnetic flowmeter, a propeller-type flowmeter, an ultrasonic flowmeter, and an electric wave flowmeter may be used.
The cleaning liquid concentration measuring unit 24 measures the chemical concentration in the cleaning liquid 28. The cleaning liquid concentration measuring unit 24 may be appropriately selected from, for example, an absorbance-type ozone concentration meter, an electrode-type ozone concentration meter, and the like, depending on the chemical agent. The cleaning liquid concentration measuring section 24 may be located downstream of the circulation pump 22, the circulation flow rate measuring section 23, and the switching section 21, and preferably closer to the inflow port 41 of the cleaning liquid storage tank 27. When the cleaning liquid concentration measuring unit 24 is disposed in the vicinity of the inlet 41 of the cleaning liquid storage tank 27, the chemical concentration when the circulated cleaning liquid 28 flows back into the cleaning liquid storage tank 27 can be measured. Therefore, the concentration of the chemical in the circulating cleaning liquid 28 can be accurately grasped.
The supply channel 4 includes a supply pump 14 and a supply flow rate measurement unit 15. Additionally, a pressure gauge 13 may be included. In the membrane filtration process, the supply channel 4 is a channel for supplying the membrane filtration water 19 to the membrane filtration water tank 18 by a membrane filtration pump 16 provided in a membrane filtration water channel 17 described later. In the cleaning process of the filtration membrane 3, the supply passage 4 is formed as a passage for supplying a part of the cleaning liquid 28 circulated in the circulation passage 25 to the filtration membrane 3 by the supply pump 14 provided in the supply passage 4.
The supply flow rate measuring unit 15 measures the flow rate of the cleaning liquid 28 in the supply flow path 4. The supply flow rate measuring unit 15 is not limited as long as it can measure the flow rate of the cleaning liquid 28 circulated through the circulation flow path 25, as in the circulation flow rate measuring unit 23.
The membrane filtration water flow path 17 includes a membrane filtration pump 16. In the membrane filtration process, the membrane filtration water 19 separated by the membrane separation tank 2 flows into the membrane filtration water tank 18 through the supply channel 4 and the membrane filtration water channel 17 by the membrane filtration pump 16.
All pumps and switching units are connected to the control unit 26. The measurement results of the supply flow rate measurement unit 15 and the circulation flow rate measurement unit 23 are sent to the control unit 26. The control unit 26 controls the operation of all pumps and switching units. The control method by the control unit 26 will be described in the water treatment method described later.
Next, a water treatment method using the water treatment apparatus 100 will be described. The water treatment method is roughly classified into a membrane filtration treatment and a cleaning treatment of the filtration membrane 3. The membrane filtration treatment is to separate and remove a dirty substance by using the filtration membrane 3 after treating the water 1 to be treated by the activated sludge method. When the membrane filtration treatment is continuously performed, there is a problem that the filtration performance is lowered. Specifically, as the filtration membrane 3 continues to be used, the surface of the filtration membrane 3 contacting the water to be treated 1, the surface of the filtration membrane 3 contacting the filtered water, and the pores of the filtration membrane 3 become clogged with the dirty substances, and the filtration performance gradually decreases. In particular, when clogging occurs in the filtration membrane 3, the pressure required at the time of the membrane filtration process increases. Thus, the membrane filtration flux, the amount of membrane filtration water per unit time and per unit membrane area decreases. Therefore, in order to maintain the performance of the filtration membrane 3, the cleaning process of the filtration membrane 3 is periodically performed.
The membrane filtration process will be described. The operation of the pump and the switching unit described later is controlled by the control unit 26.
First, the circulation flow path 25 side of the switching unit 20 is closed, the membrane separation tank 2 side and the membrane filtration water flow path 17 side are opened, and the membrane filtration pump 16 is started. Thus, the water 1 to be treated is subjected to membrane filtration by the filtration membrane 3, and the membrane-filtered water 19 filtered by the filtration membrane 3 is discharged to the membrane-filtered water tank 18 via the supply channel 4 side and the membrane-filtered water channel 17.
Next, a cleaning process of the filtration membrane 3 will be described.
When the membrane filtration process is performed, the membrane filtration pump 16 is stopped, and the membrane filtration process is ended. Then, the switching unit 20 closes the membrane filtration water flow path 17 side, and opens the membrane separation tank 2 side and the circulation flow path 25 side. After the completion of the membrane filtration process, the filtration membrane 3 may be pretreated before the cleaning process of the filtration membrane 3 is started. For example, by exposing the filtration membrane 3 to air for a certain period of time, the contaminants adhering to the surface of the filtration membrane 3 contacting the water to be treated 1 can be easily removed. In addition, a pre-cleaning liquid containing no chemical may be prepared, and the filtration membrane 3 may be pre-cleaned. By performing the pre-cleaning, the dirty substances adhering to the surface of the filtration membrane 3 contacting the water to be treated 1 can be easily removed.
Next, circulation of the cleaning liquid 28 is performed. First, the supply channel 4 side of the switching unit 21 is closed, and the outflow port 40 side and the inflow port 41 side of the cleaning liquid storage tank 27 are opened. Then, the circulation pump 22 is started, and the cleaning liquid 28 containing the chemical is circulated from the cleaning liquid storage tank 27 through the circulation flow path 25. This allows the old cleaning liquid 28 remaining in the circulation flow path 25 to be replaced with the new cleaning liquid 28. Therefore, even when the chemical in the old cleaning liquid 28 remaining in the circulation flow path 25 is decomposed, the cleaning efficiency at the initial stage of cleaning can be improved. The chemical concentration of the cleaning liquid 28 is measured by the cleaning liquid concentration measuring unit 24 provided in the circulation flow path 25. This confirms whether or not the cleaning liquid 28 can ensure a predetermined chemical concentration. At this time, the measurement result of the cleaning liquid concentration measurement unit 24 is sent to the control unit 26, and when the cleaning liquid 28 can ensure a predetermined chemical concentration, the control unit 26 can control to start supplying the cleaning liquid 28 to the filtering membrane 3 described later. Although not shown, the circulation flow path 25 may include, for example, a static mixer or the like that uniformly mixes the cleaning liquid 28.
Next, the cleaning liquid 28 is supplied to the filtration membrane 3. The switching section 21 opens all of the supply flow path 4 side, the outflow port 40 side and the inflow port 41 side of the cleaning liquid storage tank 27. Then, the supply pump 14 is started, and a part of the cleaning liquid 28 circulated in the circulation flow path 25 is supplied to the filtration membrane 3 via the supply flow path 4, thereby cleaning the filtration membrane 3 in a countercurrent manner. After the countercurrent washing, the washing liquid 28 discharged from the filtration membrane 3 is discharged into the membrane separation tank 2, and can be used as the water 1 to be treated for the membrane filtration process. Alternatively, the cleaning liquid 28 discharged from the filtration membrane 3 after the countercurrent cleaning may be recovered as the treated liquid. The cleaning liquid 28 after each backwashing treatment described later is the same as the above-described treatment.
The circulation pump 22 and the supply pump 14 are controlled by a control unit 26. At this time, the flow rate of the circulation flow path 25 is made faster than the flow rate of the supply flow path 4. In addition, the flow rate is adjusted so that the residence time of the cleaning liquid 28 from the cleaning liquid storage tank 27 to the filtration membrane 3 is the same as the residence time of the cleaning liquid 28 from the cleaning liquid storage tank 27 to the cleaning liquid concentration measuring section 24. The adjustment of the flow rate may be performed by controlling both the circulation pump 22 and the feed pump 14, or may be performed by controlling one of them.
A method of adjusting the flow rate by controlling the circulation pump 22 will be described with reference to fig. 1. First, the flow rate of the cleaning liquid 28 in the circulation flow path 25 is made faster than the flow rate of the cleaning liquid 28 in the supply flow path 4. At this time, the supply flow rate and the circulation flow rate are measured by the supply flow rate measuring unit 15 and the circulation flow rate measuring unit 23. For example, when the value of the supply flow rate measurement unit 15 is high, the input of the motor of the circulation pump 22 is increased so that the value of the circulation flow rate measurement unit 23 becomes higher than the value of the supply flow rate measurement unit 15. When the supply pump 14 is controlled, the input to the motor of the supply pump 14 is reduced so that the value of the supply flow rate measurement unit 15 becomes lower than the value of the circulation flow rate measurement unit 23. In the case of controlling both the circulation pump 22 and the supply pump 14, the inputs to the motors of the circulation pump 22 and the supply pump 14 may be adjusted so that the value of the circulation flow rate measurement unit 23 becomes higher than the value of the supply flow rate measurement unit 15.
The circulation pump 22 is controlled so that the retention time of the cleaning liquid 28 from the cleaning liquid storage tank 27 to the filtration membrane 3 is the same as the retention time of the cleaning liquid 28 from the cleaning liquid storage tank 27 to the cleaning liquid concentration measuring section 24. In this case, the supply channel 4 is formed as a channel shorter than the circulation channel 25. When the pipe diameters of the flow paths are the same, the residence time of the cleaning liquid 28 can be obtained by dividing the pipe length by the flow rate. Specifically, the residence time of the cleaning liquid 28 from the cleaning liquid storage tank 27 to the cleaning liquid concentration measuring section 24 can be obtained by dividing the piping length from the cleaning liquid storage tank 27 to the cleaning liquid concentration measuring section 24 by the flow rate obtained by the circulation flow rate measuring section 23. Further, the residence time of the cleaning liquid 28 from the cleaning liquid storage tank 27 to the filtration membrane 3 can be obtained by adding a value obtained by dividing the piping length from the cleaning liquid storage tank 27 to the switching section 21 by the flow rate obtained by the circulation flow rate measuring section 23 and a value obtained by dividing the piping length from the switching section 21 to the filtration membrane 3 by the flow rate obtained by the supply flow rate measuring section 15.
The control unit 26 controls the inputs to the motors of the supply pump 14 and the circulation pump 22 so that the residence time of the cleaning liquid 28 from the cleaning liquid storage tank 27 to the filtration membrane 3 is the same as the residence time of the cleaning liquid 28 from the cleaning liquid storage tank 27 to the cleaning liquid concentration measuring unit 24. For example, a case will be described in which the residence time from the cleaning liquid storage tank 27 to the filtration membrane 3 is longer than the residence time from the cleaning liquid storage tank 27 to the cleaning liquid concentration measuring section 24. In the case of controlling the circulation pump 22, the input to the motor of the circulation pump 22 is increased. In the case of controlling the feed pump 14, the input to the motor of the feed pump 14 is reduced. When the circulation pump 22 and the supply pump 14 are controlled, the input to the motor of the circulation pump 22 is increased, and the input to the motor of the supply pump 14 is decreased.
Thereby, the concentration of the chemical in the cleaning liquid 28 supplied to the filtration membrane 3 can be estimated from the value of the cleaning liquid concentration measuring unit 24.
As a method of adjusting the flow rate, an example of adjusting the flow rate by using the flow rate values measured by the supply flow rate measuring unit 15 and the circulation flow rate measuring unit 23 has been described. As another method, the flow rate may be measured in the supply flow rate measuring unit 15 and the circulation flow rate measuring unit 23, and the flow rate may be calculated from the measured flow rates. Specifically, when the pipe diameters of the flow paths are the same, the flow rate can be obtained by dividing the flow rate by the pipe cross-sectional area.
In the case where the flow rates are measured in the supply flow rate measuring unit 15 and the circulation flow rate measuring unit 23, the pipe diameters of the flow paths may be different. For example, the piping diameters of the supply passage 4 and the circulation passage 25 may be different. In this case, the retention time of the cleaning liquid 28 can be obtained by dividing the flow rate per unit time by the piping capacity. The pipe capacity can be obtained by multiplying the pipe cross-sectional area by the length. Therefore, the retention time of the cleaning liquid 28 from the cleaning liquid storage tank 27 to the cleaning liquid concentration measuring section 24 can be obtained by dividing the value of the flow rate obtained by the circulation flow rate measuring section 23 by the piping capacity from the cleaning liquid storage tank 27 to the cleaning liquid concentration measuring section 24. The retention time from the cleaning liquid storage tank 27 to the filtration membrane 3 can be obtained by adding the value obtained by dividing the flow rate obtained by the circulation flow rate measuring unit 23 by the piping capacity from the cleaning liquid storage tank 27 to the switching unit 21 and the value obtained by dividing the flow rate obtained by the supply flow rate measuring unit 15 by the piping capacity from the switching unit 21 to the filtration membrane 3.
The cleaning time of the filtration membrane 3 using the cleaning liquid 28 containing the chemical can be appropriately set according to the amount of the contaminant adhering to the filtration membrane 3, and the like. In general, it is preferable to use sodium hypochlorite for 90 minutes or less, to use ozone water for 60 minutes or less, and to use oxalic acid or citric acid for 5 minutes to 7 minutes. If the cleaning time is prolonged, the time during which the membrane treatment of the treated water 1 is interrupted is also prolonged, and the amount of the membrane filtration water is reduced, so that the shorter the cleaning time is, the better.
The membrane surface permeation flux, which is the amount of water supplied per unit membrane area of the cleaning liquid 28 containing the chemical, is not limited. Typically, onlyThe flux to be filled into the end of the filtration membrane 3 may be ensured. In particular, in the case of using sodium hypochlorite, it is preferably 6LMH (L/(m) 2 H) is preferably 30LMH (L/(m) 2 H)) is as follows. If the membrane surface permeation flux is too high, the cost of the chemical increases with an increase in the necessary amount of the cleaning liquid 28, the capacity of the chemical tank increases, or the filtration membrane 3 breaks. If the membrane surface permeation flux is too low, the cleaning liquid 28 does not fill the end of the filtration membrane 3, and the contaminants adhering to the filtration membrane 3 cannot be decomposed, or if ozone is used in the chemical, the concentration in the supply is lowered.
As the method for cleaning the filtration membrane 3 according to the present embodiment, a cleaning method in which the cleaning liquid 28 is passed through the filtration membrane 3 and then the cleaning liquid 28 is held in the membrane as it is, a cleaning method in which the filtration membrane 3 is immersed in the cleaning liquid 28 and then held, or the like can be used.
After the cleaning process of the filtration membrane 3 is completed, the circulation pump 22 and the supply pump 14 are stopped, the circulation flow path 25 side of the switching unit 20 is closed, and the membrane filtration pump 16 is opened. Then, the membrane filtration pump 16 is started, and the membrane filtration treatment of the water 1 to be treated can be performed again. This enables the membrane filtration treatment of the water 1 to be treated to be continuously and efficiently performed.
The conventional cleaning device for the filtration membrane 3 supplies the cleaning liquid 28 from the cleaning liquid storage tank 27 to the filtration membrane 3 at a constant flow rate. Therefore, when the flow path length from the cleaning liquid storage tank 27 to the filtration membrane 3 is long, the chemical in the cleaning liquid is decomposed during the supply, and the concentration is reduced. In addition, if the flow rate is increased in order to supply the cleaning liquid before the decomposition of the chemical, the amount of the cleaning liquid used increases.
The apparatus for cleaning the filtration membrane 3 in the present embodiment includes: a circulation flow path 25 connecting the outflow port 40 and the inflow port 41 of the cleaning liquid storage tank 27; and a supply channel 4 for supplying the circulated cleaning liquid 28 to the filtration membrane 3. Further, at least one of the circulation pump 22 and the supply pump 14 is controlled so that the flow rate of the cleaning liquid 28 is faster in the circulation flow path 25 than in the supply flow path 4. By making the circulation flow rate of the cleaning liquid 28 faster than the supply flow rate to the filtration membrane 3, it is possible to suppress a decrease in the concentration of the chemical in the cleaning liquid 28 during the period in which the cleaning liquid 28 is supplied from the cleaning liquid storage tank 27 to the filtration membrane 3. This can maintain the chemical concentration of the cleaning liquid 28. Further, since the supply flow rate is lower than the circulation flow rate, the amount of the cleaning liquid 28 used can be reduced.
The water treatment apparatus 100 according to the present embodiment includes: as described above, the cleaning device for the filtration membrane 3 can maintain the chemical concentration of the cleaning liquid 28 and reduce the amount of the cleaning liquid 28 used. Thus, the cleaning liquid storage tank 27 can be provided at a remote place, and thus the degree of freedom in design of the water treatment apparatus 100 increases. Further, since the cleaning liquid storage tank 27 can be separately provided, the degree of freedom in the installation place of the water treatment apparatus 100 increases.
Further, since the water treatment apparatus 100 repeats the membrane filtration process and the cleaning process of the filtration membrane 3, the supply and the stop of the cleaning liquid 28 are repeated. Therefore, during the period in which the supply of the cleaning liquid 28 is stopped, the chemical in the cleaning liquid 28 remaining in the flow path may be decomposed. The water treatment apparatus 100 according to the present embodiment circulates the cleaning liquid 28 before supplying the cleaning liquid 28 to the filtration membrane 3. This allows the old cleaning liquid 28 remaining in the circulation flow path 25 to be replaced with the new cleaning liquid 28. Therefore, even when the chemical in the old cleaning liquid 28 remaining in the circulation flow path 25 is decomposed, the cleaning efficiency in the initial stage of cleaning can be improved. The chemical concentration of the cleaning liquid 28 is measured by the cleaning liquid concentration measuring unit 24 provided in the circulation flow path 25. Thereby, it is confirmed whether or not the cleaning liquid 28 in the cleaning liquid storage tank 27 can ensure a predetermined chemical concentration.
The residence time of the cleaning liquid 28 from the cleaning liquid storage tank 27 to the filtration membrane 3 is set to be the same as the residence time of the cleaning liquid 28 from the cleaning liquid storage tank 27 to the cleaning liquid concentration measuring section 24. This allows the concentration of the cleaning liquid 28 supplied to the filtration membrane 3 to be estimated from the value of the cleaning liquid concentration measuring unit 24. Therefore, by the 1 cleaning liquid concentration measuring section 24, it is possible to confirm whether the cleaning liquid 28 in the cleaning liquid storage tank 27 has a predetermined chemical concentration or not and the concentration of the cleaning liquid 28 supplied to the filtration membrane 3.
In the case where the cleaning liquid 28 containing 1 type of chemical is used in the cleaning device for the filtration membrane 3 of the present embodiment, a plurality of cleaning liquid storage tanks 27 may be provided and the cleaning process may be performed by the same method in the case where the cleaning liquid 28 containing 2 or more types of chemical is used.
Embodiment 2.
A water treatment apparatus 100 including a cleaning apparatus for a filtration membrane 3 in embodiment 2 will be described with reference to fig. 2. Fig. 2 is a schematic view of the water treatment apparatus 100. In embodiment 2, an example of using ozone, in which decomposition of the chemical occurs immediately after the generation of the cleaning liquid and it is particularly difficult to maintain the concentration of the chemical, as the chemical of the cleaning liquid 28 is shown. That is, the cleaning liquid storage tank 27 stores ozone water as the cleaning liquid 28. Other configurations are the same as those of embodiment 1. The same components as those of embodiment 1 are denoted by the same reference numerals.
As shown in fig. 2, a gas diffusing device 31 is disposed at the bottom of the cleaning liquid storage tank 27, and an ozone generator 29 is connected to the gas diffusing device 31 via an ozone supply pipe 30. The ozone source to be supplied to the ozone generator 29 is not limited. For example, liquid oxygen, pressure swing adsorption (PSA, pressure Swing Adsorption), pressure vacuum swing adsorption (PVSA, pressure Vacuum Swing Adsorption) generated oxygen can be used. The unnecessary ozone water is treated by the ozone-discharging treatment device 33 through the ozone-discharging pipe 32, and is discharged to the treated ozone pipe 34.
Next, a method of generating ozone water in the cleaning liquid storage tank 27 will be described. The other water treatment methods are the same as those of embodiment 1.
First, ozone gas generated by the ozone generator 29 is supplied from the gas diffusing device 31 to the cleaning liquid storage tank 27 through the ozone supply pipe 30. Thereby, ozone water is generated in the cleaning liquid storage tank 27. Then, the ozone water generated in the cleaning liquid storage tank 27 is supplied to the filtration membrane 3 through the circulation flow path 25 and the supply flow path 4, and the filtration membrane 3 is subjected to countercurrent cleaning.
As in embodiment 1, the cleaning device for the filtration membrane 3 in this embodiment includes the circulation flow path 25 and the supply flow path 4, and the flow rate of the cleaning liquid 28 is made faster in the circulation flow path 25 than in the supply flow path 4. This can maintain the chemical concentration of the cleaning liquid 28 and reduce the amount of the cleaning liquid 28 used.
Ozone gas generated by the ozone generator 29 is supplied from the gas diffusing device 31 to the cleaning liquid storage tank 27 via the ozone supply pipe 30, whereby ozone water can be generated in the cleaning liquid storage tank 27. Thus, even when the ozone water that is easily decomposed is used as the cleaning liquid 28, the concentration of the ozone water stored in the cleaning liquid storage tank 27 is easily maintained.
The case where the gas dispersing device 31 is used as the ozone gas supply device is described, but other supply devices may be used as long as ozone water can be produced. For example, an eductor type, a mechanical stirring type, a lower injection type, or other ozone gas supply device may be used.
Although the example of using ozone as the chemical is described, the cleaning liquid 28 containing ozone and the cleaning liquid 28 containing a chemical other than ozone may be used in combination.
Embodiment 3.
A water treatment apparatus 100 including a cleaning apparatus for a filtration membrane 3 according to embodiment 3 will be described with reference to fig. 3. Fig. 3 is a schematic view of the water treatment apparatus 100. The water treatment apparatus 100 according to embodiment 3 has a connection flow path 37 that connects the circulation flow path 25 to 2 positions on the inflow port 41 side of the cleaning liquid storage tank 27 with respect to the circulation pump 22 and on the outflow port 40 side of the cleaning liquid storage tank 27 with respect to the cleaning liquid concentration measuring section 24 so as to form a flow path shorter than the circulation flow path 25 from the outflow port 40 to the inflow port 41 of the cleaning liquid storage tank 27. Other configurations are the same as those of embodiment 1. The same reference numerals are given to the same components as those of embodiment 1.
For example, the circulation flow path 25 includes a switching portion 38 between the circulation pump 22 and the circulation flow rate measuring portion 23 and the switching portion 21, and includes a switching portion 39 between the switching portion 21 and the cleaning liquid concentration measuring portion 24. Further, by providing the connection flow path 37 connected to the switching portion 38 and the switching portion 39, a flow path shorter than the circulation flow path 25 can be formed from the outflow port 40 to the inflow port 41 of the cleaning liquid storage tank 27.
Next, a water treatment method using the water treatment apparatus 100 will be described.
When the filtration membrane 3 is cleaned, the cleaning liquid 28 is circulated through the connection channel 37.
The switching unit 21 side of the switching unit 38 is closed, and the circulation flow rate measuring unit 23 side and the switching unit 39 side are opened. The switching unit 39 closes the switching unit 21 side, and opens the cleaning liquid concentration measuring unit 24 side and the switching unit 38 side. Next, the circulation pump 22 is started, and the cleaning liquid 28 is circulated in the order of the outflow port 40 of the cleaning liquid storage tank 27, the switching portion 38, the connection flow path 37, the switching portion 39, and the inflow port 41 of the cleaning liquid storage tank 27. In this way, the cleaning liquid 28 is supplied to the cleaning liquid concentration measuring section 24 through the connecting passage 37 in a shorter flow path than the circulation passage 25. This makes it possible to more accurately confirm whether or not the chemical concentration in the cleaning liquid 28 supplied from the cleaning liquid storage tank 27 is a predetermined concentration.
Next, the circulation of the cleaning liquid 28 when supplied to the filtration membrane 3 will be described.
The switching unit 38 closes the switching unit 39 side, and opens the circulation flow rate measuring unit 23 side and the switching unit 21 side. The switching unit 39 closes the switching unit 38 side and opens the cleaning liquid concentration measuring unit 24 and the switching unit 21 side. The switching unit 21 closes the supply flow path 4 side, and opens the switching unit 38 side and the switching unit 39 side. Next, the circulation pump 22 is started, and the cleaning liquid 28 is circulated in the order of the outflow port 40 of the cleaning liquid storage tank 27, the switching section 21, and the inflow port 41 of the cleaning liquid storage tank 27. This allows the old cleaning liquid 28 remaining in the circulation flow path 25 to be replaced with the new cleaning liquid 28. Therefore, even when the chemical in the old cleaning liquid 28 remaining in the circulation flow path 25 is decomposed, the cleaning efficiency at the initial stage of cleaning can be improved. The other water treatment method is the same as in embodiment 1.
As in embodiment 1, the cleaning device for the filtration membrane 3 in this embodiment includes the circulation flow path 25 and the supply flow path 4, and the flow rate of the cleaning liquid 28 is made faster in the circulation flow path 25 than in the supply flow path 4. This can maintain the chemical concentration of the cleaning liquid 28 and reduce the amount of the cleaning liquid 28 used.
In addition, the cleaning liquid storage tank 27 may not be provided in the vicinity of the membrane separation tank 2. In this case, the flow path from the cleaning liquid storage tank 27 to the filtration membrane 3 becomes longer, and therefore the circulation flow path 25 from the cleaning liquid storage tank 27 to the cleaning liquid concentration measuring section 24 becomes longer. In such a water treatment apparatus 100, when the concentration of the chemical measured by the cleaning liquid concentration measuring unit 24 is low, it cannot be determined whether the concentration of the chemical in the cleaning liquid 28 supplied from the cleaning liquid storage tank 27 is low or the concentration of the chemical is reduced while the chemical is supplied to the filtration membrane 3. To solve this problem, in the present embodiment, the water treatment apparatus 100 has the connection flow path 37 that connects the circulation flow path 25 to the circulation pump 22 at 2 positions on the inflow port 41 side of the cleaning liquid storage tank 27 and the outflow port 40 side of the cleaning liquid storage tank 27 with respect to the cleaning liquid concentration measuring unit 24, so that a flow path shorter than the circulation flow path 25 is formed from the outflow port 40 to the inflow port 41 of the cleaning liquid storage tank 27. With this configuration, the concentration of the cleaning liquid 28 supplied from the cleaning liquid storage tank 27 and the concentration of the cleaning liquid 28 supplied to the filtration membrane 3 can be checked.
The configuration shown in the above embodiment is shown as an example, and may be combined with another known technique. The embodiments may be combined, and a part of the constitution may be omitted or changed without departing from the scope of the gist.
For example, embodiment mode 2 and embodiment mode 3 can be combined. Fig. 4 is a schematic view of the water treatment apparatus 100. In the water treatment apparatus 100 shown in fig. 4, the ozone generator 29 is connected to the cleaning liquid storage tank 27 via the ozone supply pipe 30. Further, the circulation pump 22 is provided with a connection channel 37 which connects to the inlet 41 side of the cleaning liquid storage tank 27 and the outlet 40 side of the cleaning liquid storage tank 27 with respect to the cleaning liquid concentration measuring unit 24 at 2 positions, so that a channel shorter than the circulation channel 25 is formed from the outlet 40 to the inlet 41 of the cleaning liquid storage tank 27.
In such an embodiment, the circulation flow path 25 and the supply flow path 4 are included, and the flow rate of the cleaning liquid 28 is made faster in the circulation flow path 25 than in the supply flow path 4. This can maintain the chemical concentration of the cleaning liquid 28 containing ozone that is easily decomposed, and reduce the amount of the cleaning liquid 28 used.
Further, even with the cleaning liquid 28 containing ozone which is easily decomposed, the ozone concentration of the cleaning liquid 28 supplied from the cleaning liquid storage tank 27 and the ozone concentration of the cleaning liquid 28 supplied to the filtration membrane 3 can be checked, respectively.
Description of the reference numerals
1 water to be treated, 2 membrane separation tank, 3 filtration membrane, 4 supply passage, 5 water to be treated passage, 6 sludge extraction passage, 7 sludge circulation passage, 8 air dispersion device, 9 sludge extraction pump, 10 sludge circulation pump, 11 air supply piping, 12 membrane surface aeration blower, 13 manometer, 14 supply pump, 15 supply flow rate measuring section, 16 filtration pump, 17 filtration water passage, 18 filtration water tank, 19 filtration water, 20 switching section, 21 switching section, 22 circulation pump, 23 circulation flow rate measuring section, 24 cleaning liquid measuring section, 25 circulation passage, 26 control section, 27 cleaning liquid storage tank, 28 cleaning liquid, 29 ozone generator, 30 ozone supply piping, 31 air dispersion device, 32 ozone discharge piping, 33 ozone treatment equipment, 34 treatment ozone piping, 36 switching section, 37 connection passage, 38 switching section, 39 switching section, 40 outflow port, 41 inflow port, 100 water treatment device
Claims (8)
1. A filtration membrane cleaning device comprising:
a cleaning liquid storage tank for storing a cleaning liquid containing a chemical for cleaning the filtration membrane, the cleaning liquid having an outflow port and an inflow port;
a circulation flow path connecting the outflow port and the inflow port of the cleaning liquid storage tank, the circulation flow path being provided with a circulation pump for circulating the cleaning liquid;
a supply flow path connected to the circulation flow path and provided with a supply pump for supplying a part of the cleaning liquid circulated in the circulation flow path to the filtration membrane; and
and a control unit that controls at least one of the circulation pump and the supply pump so that a flow rate of the cleaning liquid is faster in the circulation flow path than in the supply flow path.
2. The filtration membrane cleaning device according to claim 1, wherein the chemical contains at least ozone.
3. The apparatus for cleaning a filtration membrane according to claim 2, wherein the cleaning liquid storage tank has a gas dispersing device connected to an ozone generator.
4. A cleaning apparatus for a filtration membrane according to any one of claim 1 to 3,
the circulation flow path has a cleaning liquid concentration measuring section for measuring the concentration of the chemical in the cleaning liquid,
the control unit controls at least one of the circulation pump and the supply pump so that a residence time of the cleaning liquid from the cleaning liquid storage tank to the filtration membrane is the same as a residence time of the cleaning liquid from the cleaning liquid storage tank to the cleaning liquid concentration measuring unit.
5. The apparatus for cleaning a filtration membrane according to claim 4, wherein the apparatus comprises a connection channel that connects the circulation channel to the circulation pump at 2 positions on the inflow port side of the cleaning liquid storage tank and the outflow port side of the cleaning liquid storage tank with respect to the cleaning liquid concentration measuring section such that the circulation channel is shorter from the outflow port to the inflow port of the cleaning liquid storage tank.
6. A water treatment device, comprising:
a membrane separation tank having a filtration membrane for performing membrane filtration treatment on water to be treated;
a membrane filtration water tank for storing membrane filtration water subjected to membrane filtration treatment by using the membrane separation tank;
a cleaning liquid storage tank for storing a cleaning liquid containing a chemical for cleaning the filtration membrane, the cleaning liquid having an outflow port and an inflow port;
a circulation flow path connecting the outflow port and the inflow port of the cleaning liquid storage tank, the circulation flow path being provided with a circulation pump for circulating the cleaning liquid;
a supply flow path connected to the circulation flow path and provided with a supply pump for supplying a part of the cleaning liquid circulated in the circulation flow path to the filtration membrane; and
and a control unit that controls at least one of the circulation pump and the supply pump so that a flow rate of the cleaning liquid is faster in the circulation flow path than in the supply flow path.
7. A method for cleaning a filtration membrane, characterized in that a cleaning liquid is circulated in a circulation flow path connecting an outflow port and an inflow port of a cleaning liquid storage tank storing the cleaning liquid,
supplying a part of the cleaning liquid circulated in the circulation flow path to the filtration membrane via a supply flow path for supplying a part of the cleaning liquid circulated in the circulation flow path from the circulation flow path to the filtration membrane,
the flow rate of the cleaning liquid is made faster in the circulation flow path than in the supply flow path.
8. The method for cleaning a filtration membrane according to claim 7, wherein the concentration of the chemical in the cleaning solution is measured by a cleaning solution concentration measuring section provided in the circulation flow path,
the residence time from the cleaning liquid storage tank to the filtration membrane is made the same as the residence time from the cleaning liquid storage tank to the cleaning liquid concentration measuring section.
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| PCT/JP2021/002232 WO2022157926A1 (en) | 2021-01-22 | 2021-01-22 | Cleaning device for filtration membrane, water treatment device, and cleaning method for filtration membrane |
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| JP (1) | JP7067678B1 (en) |
| CN (1) | CN116710193A (en) |
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11179163A (en) * | 1997-12-25 | 1999-07-06 | Ebara Corp | Method for back washing of inner pressure type membrane module for removing pollutant by fluctuation of flow rate and pressure |
| CN102686141A (en) * | 2009-12-25 | 2012-09-19 | 松下电器产业株式会社 | Cleaning apparatus and cleaning method |
| JP2014018782A (en) * | 2012-07-23 | 2014-02-03 | Mitsui Eng & Shipbuild Co Ltd | System and method for cleaning filtration film of ballast water treatment |
| US20140151294A1 (en) * | 2012-11-30 | 2014-06-05 | Tangent Company Llc | Method and Apparatus for Residential Water Recycling |
| EP3012012A1 (en) * | 2013-06-21 | 2016-04-27 | Toray Industries, Inc. | Filter device, manufacturing device for chemical, and operation method for filter device |
| JP2016185520A (en) * | 2015-03-27 | 2016-10-27 | 栗田工業株式会社 | Chemical cleaning method and chemical cleaning apparatus for reverse osmosis membrane device |
| US20200197872A1 (en) * | 2017-08-23 | 2020-06-25 | Mitsubishi Electric Corporation | Water treatment membrane washing apparatus and water treatment membrane washing method |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3285848B2 (en) * | 1999-09-02 | 2002-05-27 | 株式会社クボタ | Backwashing method and apparatus for immersion type membrane separation device |
| JP2001187324A (en) * | 1999-12-28 | 2001-07-10 | Nkk Corp | Washing method of membrane filter device, and water treating device |
| JP3856376B2 (en) * | 2002-03-05 | 2006-12-13 | 富士電機ホールディングス株式会社 | Water treatment device and its operation method |
| WO2020255201A1 (en) * | 2019-06-17 | 2020-12-24 | 三菱電機株式会社 | Filtration membrane cleaning apparatus, filtration membrane cleaning method and water treatment system |
-
2021
- 2021-01-22 CN CN202180090940.2A patent/CN116710193A/en active Pending
- 2021-01-22 JP JP2021552905A patent/JP7067678B1/en active Active
- 2021-01-22 WO PCT/JP2021/002232 patent/WO2022157926A1/en active Application Filing
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11179163A (en) * | 1997-12-25 | 1999-07-06 | Ebara Corp | Method for back washing of inner pressure type membrane module for removing pollutant by fluctuation of flow rate and pressure |
| CN102686141A (en) * | 2009-12-25 | 2012-09-19 | 松下电器产业株式会社 | Cleaning apparatus and cleaning method |
| JP2014018782A (en) * | 2012-07-23 | 2014-02-03 | Mitsui Eng & Shipbuild Co Ltd | System and method for cleaning filtration film of ballast water treatment |
| US20140151294A1 (en) * | 2012-11-30 | 2014-06-05 | Tangent Company Llc | Method and Apparatus for Residential Water Recycling |
| EP3012012A1 (en) * | 2013-06-21 | 2016-04-27 | Toray Industries, Inc. | Filter device, manufacturing device for chemical, and operation method for filter device |
| JP2016185520A (en) * | 2015-03-27 | 2016-10-27 | 栗田工業株式会社 | Chemical cleaning method and chemical cleaning apparatus for reverse osmosis membrane device |
| US20200197872A1 (en) * | 2017-08-23 | 2020-06-25 | Mitsubishi Electric Corporation | Water treatment membrane washing apparatus and water treatment membrane washing method |
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| Publication number | Publication date |
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| WO2022157926A1 (en) | 2022-07-28 |
| JPWO2022157926A1 (en) | 2022-07-28 |
| JP7067678B1 (en) | 2022-05-16 |
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