WO2015045574A1 - 淡水化装置及び淡水化方法 - Google Patents
淡水化装置及び淡水化方法 Download PDFInfo
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- WO2015045574A1 WO2015045574A1 PCT/JP2014/068700 JP2014068700W WO2015045574A1 WO 2015045574 A1 WO2015045574 A1 WO 2015045574A1 JP 2014068700 W JP2014068700 W JP 2014068700W WO 2015045574 A1 WO2015045574 A1 WO 2015045574A1
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
- B01D61/14—Ultrafiltration; Microfiltration
- B01D61/22—Controlling or regulating
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
- B01D61/58—Multistep processes
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- 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
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- 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
- C02F1/441—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by reverse osmosis
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- 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
- C02F1/444—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by ultrafiltration or microfiltration
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2311/00—Details relating to membrane separation process operations and control
- B01D2311/14—Pressure control
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2321/00—Details relating to membrane cleaning, regeneration, sterilization or to the prevention of fouling
- B01D2321/04—Backflushing
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2321/00—Details relating to membrane cleaning, regeneration, sterilization or to the prevention of fouling
- B01D2321/16—Use of chemical agents
- B01D2321/168—Use of other chemical agents
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2321/00—Details relating to membrane cleaning, regeneration, sterilization or to the prevention of fouling
- B01D2321/40—Automatic control of cleaning processes
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
- B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
- B01D61/025—Reverse osmosis; Hyperfiltration
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
- B01D61/14—Ultrafiltration; Microfiltration
- B01D61/145—Ultrafiltration
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
- B01D61/14—Ultrafiltration; Microfiltration
- B01D61/147—Microfiltration
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- 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
- C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
- C02F1/5236—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents
- C02F1/5245—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents using basic salts, e.g. of aluminium and iron
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- 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
- C02F1/72—Treatment of water, waste water, or sewage by oxidation
- C02F1/76—Treatment of water, waste water, or sewage by oxidation with halogens or compounds of halogens
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
- C02F2103/08—Seawater, e.g. for desalination
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2303/00—Specific treatment goals
- C02F2303/16—Regeneration of sorbents, filters
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A20/00—Water conservation; Efficient water supply; Efficient water use
- Y02A20/124—Water desalination
- Y02A20/131—Reverse-osmosis
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W10/00—Technologies for wastewater treatment
- Y02W10/30—Wastewater or sewage treatment systems using renewable energies
- Y02W10/37—Wastewater or sewage treatment systems using renewable energies using solar energy
Definitions
- the present invention relates to a desalination method and a desalination apparatus for desalinating seawater or brackish water to desalinate.
- RO reverse osmosis
- Patent Document 1 describes that a separation membrane such as a UF membrane (ultrafiltration membrane) or an MF membrane (microfiltration membrane) is used as a pretreatment membrane (see FIG. 2).
- An object of the present invention is to provide a desalination method and apparatus capable of performing reverse osmosis membrane filtration efficiently and stably over a long period of time.
- a desalination method in a desalination apparatus comprising a filtration membrane for removing soluble organic substances and turbid components in raw water, and a reverse osmosis membrane, When the transmembrane pressure difference obtained by measuring the inflow pressure of the raw water flowing into the filtration membrane and the outflow pressure of the permeated water flowing out of the filtration membrane reaches a predetermined value or when the set time elapses, whichever comes first
- a desalination method comprising a filtration membrane backwashing step for starting backwashing of the filtration membrane.
- the backwashing of the filtration membrane is characterized in that the permeated water that has permeated the filtration membrane or the reverse osmosis membrane permeated water that has permeated the reverse osmosis membrane is used as it is or as a warming solution.
- the predetermined value of the transmembrane pressure difference is set in a range of 25 kPa to 100 kPa
- the desalination method according to any one of [1] to [3], wherein the set time is set in a range of 1 to 10 times the time required for the transmembrane pressure difference to reach a predetermined value.
- the method further includes controlling the addition time and / or amount of the oxidizing agent added to the cleaning liquid according to the time required for the transmembrane pressure difference to reach a predetermined value.
- the desalination method according to any one of the above.
- the method further includes controlling the addition time and / or amount of the flocculant added to the raw water according to the time required for the transmembrane pressure difference to reach a predetermined value.
- the desalination method according to any one of the above. [7] including a plurality of the filtration membranes, Measure the transmembrane pressure difference of at least one filtration membrane, determine the cleaning interval according to the time required until the transmembrane pressure pressure reaches a predetermined value, The desalination method according to any one of [1] to [6], wherein the other filtration membrane is backwashed according to the washing interval.
- a desalination apparatus comprising a filtration membrane for removing soluble organic substances and turbid components in raw water, and a reverse osmosis membrane, A raw water supply pipe that encloses the filtration membrane and supplies raw water to the filtration membrane, a permeate outflow pipe that flows out permeate from the filtration membrane, a cleaning liquid supply pipe that supplies cleaning liquid to the filtration membrane, and A filtration membrane module connected to a washing waste liquid outflow pipe for discharging washing waste liquid from the filtration membrane; Inflow pressure measuring means for measuring the pressure of the raw water in the raw water supply pipe; An outflow pressure measuring means for measuring the pressure of the permeate in the permeate outflow pipe; Based on the measurement results from the inflow pressure measuring means and the outflow pressure measuring means, the transmembrane pressure difference is calculated, either when the transmembrane pressure difference reaches a predetermined value or when a predetermined set time has elapsed.
- a desalination apparatus comprising: [9] The cleaning liquid supply pipe is connected to the permeate outflow pipe and a reverse osmosis membrane permeated water supply pipe that sends the reverse osmosis membrane permeated water that has passed through the reverse osmosis membrane to the cleaning liquid supply pipe of the filtration membrane module. And Each of the permeate outflow pipe and the reverse osmosis membrane permeate water supply pipe is provided with a flow control valve, The desalination apparatus according to [8], wherein the flow rate control valve is controlled by the control means so as to send either permeated water or reverse osmosis membrane permeated water as a cleaning liquid to the cleaning liquid supply pipe.
- a sand filtration tank connected to the raw water supply pipe is further provided, The desalination apparatus according to any one of [8] to [12], wherein raw water filtered by the sand filtration tank is supplied to the filtration membrane module.
- the desalination apparatus according to any one of [8] to [13], wherein the cleaning liquid supply pipe is provided between the permeated water storage tank and the filtration membrane module.
- [15] including a plurality of the filtration membrane modules;
- the control means determines a cleaning interval according to a time required until the transmembrane pressure difference of at least one filtration membrane module reaches a predetermined value, and backwashes other filtration membrane modules according to the determined cleaning interval.
- the desalination apparatus according to any one of [8] to [14], wherein [16] The raw water supply pipe, the permeated water outflow pipe, the cleaning liquid supply pipe, and the cleaning waste liquid outflow pipe are provided with control valves controlled by the control means, [8] to [15] The desalination apparatus of any one of these.
- reverse osmosis membrane filtration can be carried out efficiently and stably over a long period of time by backwashing the filtration membrane before the filtration membrane provided upstream of the reverse osmosis membrane is blocked.
- a desalination apparatus and a desalination method including a washing control mechanism are provided.
- the backwashing of the filtration membrane can be automatically controlled following the fluctuation of the raw water quality, the performance of the filtration membrane can be maintained optimally.
- the addition amount of the oxidizing agent used for the backwashing of the filtration membrane can be optimized, the running cost can be suppressed.
- FIG. 1 It is a schematic explanatory drawing of the desalination apparatus (mode which a control system controls only opening / closing of a valve) used in Example 1.
- FIG. It is a schematic explanatory drawing of the desalination apparatus (mode which uses reverse osmosis membrane permeated water as a washing
- FIG. It is a schematic explanatory drawing of the desalination apparatus (mode which uses the heated washing
- FIG. 1 It is a schematic explanatory drawing of the desalination apparatus (mode which a control system controls only opening / closing of a valve) used in Example 1.
- FIG. It is a schematic explanatory drawing of the desalination apparatus (mode which uses reverse osmosis membrane permeated water as a washing
- FIG. It is a schematic explanatory drawing of the desalination apparatus (mode which uses the heated washing
- the desalination apparatus shown in FIG. 1 includes a filtration membrane module 10 that contains a filtration membrane that removes soluble organic substances and turbid components in raw water, and a permeate storage tank 20 that stores permeate from the filtration membrane module 10. And a reverse osmosis membrane module 30 for desalting the permeated water.
- the filtration membrane module 10 includes a raw water supply pipe 13 for supplying raw water such as seawater for desalination, a permeated water outflow pipe 15 for flowing out permeated water, and a cleaning liquid supply pipe 22 for supplying cleaning liquid for backwashing the filtration membrane.
- the cleaning waste liquid outflow pipe 11 that flows out the cleaning waste liquid, the air supply pipe 12, and the drain 14 are connected.
- the raw water supply pipe 13 is connected to an inflow pressure measurement pressure gauge P1 for measuring the pressure of the raw water in the raw water supply pipe.
- the permeated water outflow pipe 15 is connected to an outflow pressure measuring pressure gauge P2 for measuring the pressure of the permeated water in the permeated water outflow pipe.
- These pressure gauges P1 and P2 include a transmembrane pressure difference ([P2] ⁇ [P2]-[P2] based on measurement signals [P1] and [P2] from an inflow pressure measurement pressure gauge P1 and an outflow pressure measurement pressure gauge P2.
- the control system C includes a cleaning liquid supply control valve V1 provided in the cleaning liquid supply pipe 22, a cleaning waste liquid control valve V2 provided in the cleaning wastewater pipe 11, and a permeated water control valve V3 provided in the permeate outflow pipe 15. Then, the opening and closing of the raw water control valve V4 provided in the raw water supply pipe 13 is controlled to switch between the desalination treatment and the backwashing. That is, at the time of backwashing, the raw water control valve V4 and the permeated water control valve V3 are closed, and the cleaning liquid supply control valve V1 and the cleaning waste liquid control valve V2 are opened. When the backwashing is completed, the cleaning liquid supply control valve V1 and the cleaning waste liquid control valve V2 are closed, the raw water control valve V4 and the permeated water control valve V3 are opened, and the desalination process is resumed.
- the cleaning liquid supply pipe 22 is connected to the permeated water storage tank 20 and uses permeated water as the cleaning liquid.
- the cleaning liquid may be supplied from a cleaning liquid storage tank (not shown).
- An oxidant addition means 27 is connected to the cleaning liquid supply pipe 22 to supply an oxidant to the cleaning liquid.
- the desalination apparatus shown in FIG. 2 includes an oxidizing agent addition means 27 controlled by the control system C in addition to the configuration of the desalination apparatus shown in FIG.
- the oxidant addition means 27 includes an oxidant storage tank (not shown) for storing the oxidant, a pipe for supplying the oxidant from the oxidant storage tank to the cleaning liquid supply pipe 22, and an oxidant supply adjustment provided in the pipe. And a valve (not shown).
- the opening and closing of the oxidant supply control valve is controlled by the control system C according to the time required for the transmembrane pressure difference ([P2]-[P1]) to reach a predetermined value.
- the oxidant addition flow rate in the oxidant addition means can be increased or decreased by controlling the degree of opening of the oxidant supply control valve.
- the desalination apparatus shown in FIG. 3 includes a flocculant addition means 28 connected to the raw water supply pipe 13 in addition to the configuration of the desalination apparatus shown in FIG.
- the flocculant addition means 28 includes a flocculant storage tank (not shown) for storing the flocculant, a pipe for supplying the flocculant from the flocculant storage tank to the raw water supply pipe 13, and a flocculant supply control provided in the pipe. And a valve (not shown).
- the flocculant supply control valve is controlled by the control system C according to the time required for the transmembrane pressure difference ([P2]-[P1]) to reach a predetermined value.
- the flocculant addition flow rate in the flocculant addition means can be increased or decreased by controlling the degree of opening of the flocculant supply control valve.
- the desalination apparatus shown in FIG. 4 includes a flocculant addition means 28 connected to the raw water supply pipe 13 shown in FIG. 3 in addition to the configuration of the desalination apparatus shown in FIG. That is, it is an apparatus provided with oxidant supply control and flocculant addition control, and the description of FIG. 2 and FIG. 3 is used.
- the desalination apparatus shown in FIG. 5 includes a sand filtration tank 40 connected to the raw water supply pipe 13 in addition to the configuration of the desalination apparatus shown in FIG.
- the sand filtration tank 40 is provided between the flocculant addition means 28 and the filtration membrane module 10.
- the desalination apparatus shown in FIG. 6 includes a plurality of filtration membrane modules 10 and 10a, and it is necessary for the transmembrane pressure difference ([P2]-[P1]) of at least one filtration membrane module 10 to reach a predetermined value.
- cleaning interval determined according to time is shown.
- the filtration membrane module 10a has a raw water supply pipe 13a provided with a raw water supply control valve V4a, a filtered water outflow pipe 15a provided with a filtered water control valve V3a, and a cleaning liquid supply provided with a cleaning liquid supply control valve V1a.
- a cleaning waste water pipe 11a provided with a pipe 22a and a cleaning waste liquid control valve V2a is connected.
- Each valve of the filtration membrane module 10a is controlled to be opened and closed by the control system C according to the washing interval determined according to the transmembrane differential pressure ([P2]-[P1]) of the filtration membrane module 10, and the supply of raw water is adjusted during backwashing.
- the valve V4a and the filtrate control valve V3a are closed, and the cleaning liquid supply control valve V1a and the cleaning waste liquid control valve V2a are opened.
- the control system C includes a collection unit for measured values such as pressure data and flow rate data measured by a pressure gauge, a calculation unit for collected data, a timer, a timer, and a driving unit such as a control valve and a pump based on the calculation result.
- An instruction unit for sending an operation instruction is included.
- the desalination apparatus shown in FIG. 8 includes a reverse osmosis membrane permeated water feed pipe 32 that sends reverse osmosis membrane permeated water as a cleaning liquid in addition to the configuration of the desalination apparatus shown in FIG.
- the reverse osmosis membrane permeate water supply pipe 32 is connected to the cleaning liquid supply pipe 22 and includes a flow rate control valve V5.
- the flow control valve V5 is controlled to be opened and closed by the control system C.
- the control system C controls the cleaning liquid supply control valve V1 provided in the cleaning liquid supply pipe 22 and the flow rate control valve V5 provided in the reverse osmosis membrane permeated water supply pipe 32 to thereby transmit permeated water or reverse osmosis.
- Either membrane permeated water is supplied as a cleaning liquid to the filtration membrane.
- the control system C closes the cleaning liquid supply control valve V1 and reverse osmosis membrane permeated water.
- the flow control valve V5 of the water supply pipe 32 is opened, and a route for introducing the reverse osmosis membrane permeated water as the cleaning liquid into the filtration module 10 via the cleaning liquid supply pipe 22 is selected.
- the control system C closes the flow rate control valve V5 and the cleaning liquid supply control valve V1. Is selected, and a route for introducing permeated water into the cleaning liquid supply pipe 22 as a cleaning liquid is selected.
- the desalination apparatus shown in FIG. 9 branches from the heating tank 42, the cleaning liquid supply pipe 22 and the reverse osmosis membrane permeated water supply pipe 32 to the heating tank 42.
- branch pipes 24 and 34 for feeding water, and a heated washing liquid return pipe 44 for returning the water from the heating tank 42 to the reverse osmosis membrane permeated water feed pipe 32.
- the branch pipes 24 and 34 are provided with control valves V6 and V7, respectively, and the opening and closing of the valves are controlled by the control system C.
- the control system C uses the cleaning liquid supply control valve provided in the cleaning liquid supply pipe 22.
- V1 is closed
- the flow control valve V5 provided in the reverse osmosis membrane permeate water supply pipe 32 is closed
- the control valve V7 provided in the branch pipe 34 is opened, and the reverse osmosis membrane permeate water is heated.
- the control system C closes the cleaning liquid supply control valve V1 and After the control valve V6 provided in the branch 24 is opened, the permeated water is introduced into the heating tank 42 and heated, and then at a position subsequent to the flow rate control valve V5 via the heated cleaning liquid return pipe 44. A route to be returned to the reverse osmosis membrane permeate water supply pipe 32 and introduced into the filtration membrane module 10 via the cleaning liquid supply pipe 22 is selected.
- the control system C closes the flow control valve V5 and opens the cleaning liquid supply control valve V1.
- a route for introducing the permeated water as the cleaning liquid into the cleaning liquid supply pipe 22 is selected.
- the heating tank a known heating tank such as a thermostatic tank equipped with a heater, a heat exchange device, or a solar heat utilization type heating device can be used.
- the filtration membrane and reverse osmosis membrane used in the desalination apparatus of the present invention may be a membrane used in a normal desalination apparatus.
- a microfiltration membrane or an ultrafiltration membrane can be preferably exemplified.
- membrane materials organic materials such as polyethylene (PE), polypropylene (PP), polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), polyethersulfone (PES), polysulfone (PS), cellulose acetate (CA), etc. And inorganic materials such as ceramics and metals. It is preferable that it is excellent in chemical resistance, and PVDF is suitable.
- the pore diameter of the membrane is preferably 0.001 to 1 ⁇ m.
- a hollow fiber, a tubular, a flat membrane, or the like can be adopted.
- a pressure type cylindrical module made of a hollow fiber membrane is preferable.
- Suitable examples of the reverse osmosis membrane include a semipermeable membrane made of cellulose acetate polymer, polyamide, polyester, polyimide, vinyl polymer and the like, which can obtain a very high desalting rate.
- Raw water which is seawater or brackish water is passed through the filtration membrane module 10.
- Seawater or brackish water is not only salt water but also contains a lot of turbidity and soluble organic matter depending on the water intake area.
- the raw water introduced into the filtration membrane module 10 is filtered by the filtration membrane. Most salt water is permeated and discharged, but turbidity and some soluble organic matter accumulate on the membrane surface and in the module.
- the desalination method of the present invention measures the inflow pressure of raw water flowing into the filtration membrane and the outflow pressure of permeate flowing out of the filtration membrane in the desalination apparatus of the preferred embodiment shown in FIGS.
- the filtration membrane backwashing step starts the backwashing of the filtration membrane when the transmembrane pressure difference ([P2]-[P1]) obtained in this way reaches a predetermined value or when a predetermined set time elapses, whichever comes first It is characterized by including.
- the predetermined value of the transmembrane pressure difference varies depending on the design concept.
- the transmembrane pressure difference ([P2]-[P1]) can be set in the range of 20 kPa to 100 kPa, preferably 25 kPa to 60 kPa, more preferably 25 kPa to 45 kPa.
- a set pressure that sufficiently decreases to the initial pressure (pressure due to resistance of only the membrane filtration resistance and the piping resistance by subtracting the increase in resistance due to the dirt component) by one backwashing is preferable. For example, if the initial pressure is 20 kPa and the cleaning effect is 8 kPa by one backwash, the set pressure is preferably 25 to 28 kPa.
- the set time can be in the range of 1 to 10 times, preferably 1 to 5 times the time required for the transmembrane pressure difference ([P2]-[P1]) to reach a predetermined value.
- the predetermined value of the transmembrane pressure difference (P2-P1) is set to 35 kPa
- the predetermined time is preferably 30 to 600 minutes. Is set to 30 to 300 minutes, and if the time required to reach 35 kPa is 60 to 120 minutes, the predetermined time is set to 60 to 1200 minutes, preferably 60 to 600 minutes.
- the predetermined time can be set to 120 to 1200 minutes, preferably 120 to 600 minutes.
- the backwash time is in the range of 1 minute to 15 minutes, preferably 2 minutes to 10 minutes, more preferably 3 minutes to 8 minutes.
- the transmembrane pressure difference ([P2]-[P1]) is not only a clogging state of the filtration membrane but also an indicator of fluctuations in the quality of raw water. If the quality of the raw water is deteriorated, the filtration membrane is rapidly clogged, so that the time for reaching the predetermined transmembrane pressure difference is shortened and the frequency of backwashing is increased. Conversely, if the quality of the raw water is good, the progress of the filtration membrane clogging is slowed down, so that the time for reaching the predetermined transmembrane pressure difference is prolonged and the frequency of backwashing is reduced.
- the desalination apparatus is continuously operated without performing backwashing for an excessively long time, organic substances and suspensions accumulated in the filtration membrane may be consolidated and cannot be removed even by backwashing.
- the transmembrane pressure difference ([P2]-[P1]) does not reach a predetermined value, the filtration performance of the filtration membrane can be maintained by performing backwashing when a predetermined time has elapsed.
- the frequency of backwashing can be arbitrarily set, but it is preferable to perform the washing at a rate of approximately once every 15 minutes to 3 hours.
- Back washing is performed by passing the washing solution from the permeate side of the filtration membrane to the raw water supply side. Backwashing removes turbid components and some soluble organic substances accumulated on the surface of the filtration membrane from the filtration membrane. At this time, a more effective cleaning effect can be obtained by scrubbing air from the air supply pipe 12 into the filtration membrane module 10. Although scrubbing is effective even when carried out alone, it becomes more effective when used in combination with backwashing. The scrubbing time can be set arbitrarily, but it may be about 10 seconds to 5 minutes.
- cleaning liquid used for backwashing normal cleaning liquid, permeated water that has passed through the filtration membrane, heated permeated water, reverse osmosis membrane permeated water, or heated reverse osmosis membrane permeated water can be used.
- Permeated permeate, heated permeate, reverse osmosis membrane permeate, or warmed reverse osmosis membrane permeate is preferred.
- turbidity is removed, but some soluble organic substances may remain.
- Reverse osmosis membrane permeated water is close to pure water and contains a very small amount of soluble organic matter. In particular, when the quality of seawater deteriorates, the quality of the permeated water often deteriorates, but the quality of the reverse osmosis membrane permeated water hardly deteriorates.
- the higher the temperature of the cleaning liquid the higher the cleaning effect.
- the heated cleaning liquid has a water temperature difference of 10 ° C. or higher, preferably 15 ° C. or higher, with the raw water.
- the cleaning liquid depends on the transmembrane pressure difference ([P2]-[P1]). It is selected by setting the control system C to select accordingly.
- the time required for the transmembrane pressure difference ([P2]-[P1]) to reach a predetermined value is an indicator of the water quality fluctuation of the raw water.
- the time required for the transmembrane pressure difference ([P2]-[P1]) to reach a predetermined value is short, the quality of the raw water is deteriorated, and conversely, the quality of the raw water is good.
- An automatic control operation can be performed by obtaining in advance a criterion for determining which cleaning liquid to use in accordance with the water quality and setting it in the control system C.
- An oxidizing agent may be added to the cleaning liquid used for backwashing.
- an oxidizing agent used for backwashing a normal desalination apparatus can be used without limitation, and a chlorine-based oxidizing agent is preferable, and a chlorine-based oxidizing agent such as sodium hypochlorite is particularly preferable.
- the amount of chlorinated oxidant added is usually in the range of 1 mg / L to 100 mg / L, although it depends on the quality of seawater and brackish water.
- the addition of the oxidant to the cleaning liquid is preferably controlled according to the transmembrane pressure difference ([P2]-[P1]).
- the time required for the transmembrane pressure difference ([P2]-[P1]) to reach a predetermined value, that is, the backwash interval is an indicator of the clogging state of the filtration membrane and the water quality fluctuation of the raw water.
- the backwash interval is short, the filtration membrane is clogged, so the amount of oxidant added is increased or the addition time is lengthened.
- the backwash interval is long, the filtration membrane is not clogged, so the amount of oxidant added is reduced or the addition time is shortened.
- the normal backwash interval is 60 to 120 minutes
- the addition amount is 30 mg / L
- the addition time is 45 seconds.
- the backwash interval is shortened to 30-60 minutes
- the amount of sodium hypochlorite added is increased to 50 mg / L and added for 45 seconds, or the addition time is kept at 30 mg / L for 60 seconds.
- the sodium hypochlorite addition amount is reduced to 10 mg / L and added for 45 seconds, or the addition time is kept at 30 mg / L. Reduce to 30 seconds.
- the cleaning effect of the filtration membrane is enhanced, so that the amount of chlorine-based oxidizing agent added can be reduced.
- the amount and time of addition of the conventional oxidizer depended on the quality of the raw water, it could not be adjusted when the quality of the raw water was the same.
- the adjustment of the addition of the oxidant depends on the transmembrane pressure difference (P2-P1). It is possible to obtain an optimum amount of oxidizing agent added.
- a flocculant may be added to the raw water.
- a flocculant used in a normal desalination treatment can be used without limitation, and an iron-based inorganic flocculant is preferable, and ferric chloride is particularly preferable.
- the amount of the flocculant added depends on the quality of the raw water, but is usually in the range of 0.1 to 10 mg-Fe / L.
- the flocculant may be added continuously or intermittently.
- the addition of the flocculant to the raw water is also preferably controlled according to the transmembrane pressure difference ([P2]-[P1]).
- the time required for the transmembrane pressure difference ([P2]-[P1]) to reach a predetermined value, that is, the backwash interval is an indicator of the quality of the raw water.
- the backwash interval is short, the quality of the raw water is deteriorated, and when the backwash interval is long, the quality of the raw water is good.
- the water quality is improved when the backwashing interval varies from 30 to 60 minutes.
- the amount of ferric chloride added is increased to 4 mg / L and the backwash interval fluctuates from 120 to 240 minutes, it can be determined that the water quality has improved. Reduce the ferric addition to 1 mg / L.
- an ultrafiltration membrane made of PVDF having a pore size of 0.01 ⁇ m is used as a filtration membrane, and the inside of a pressurized cylindrical filtration membrane module made of a hollow fiber membrane is filled. did.
- a polyamide membrane was used as the reverse osmosis membrane.
- Example 1 Using the desalination apparatus shown in FIG. 7 (an embodiment in which only the opening and closing of the valve is controlled by the control system C), seawater was taken in and the desalination process was performed.
- the amount of treated water was 10 m 3 / d, and the sand filtration was backwashed at a rate of once / one day to two days.
- the ultrafiltration membrane was washed (backwashed) under automatic control in which backwashing was performed when the transmembrane pressure difference reached 35 kPa. Further, when the transmembrane pressure did not reach 35 kPa and the time during which backwashing was not performed was 360 minutes, the backwashing was forcibly performed.
- a cleaning solution was used in which sodium hypochlorite was added to UF permeated water that passed through the ultrafiltration membrane to a concentration of 10 mg / L.
- the treatment status for about 6 months was approximately 10 times a day when the TOC of raw water was 1.0 mg / L, whereas 1 day when the TOC was 1.5 mg / L.
- Backwashing was performed about 40 times. The average number of backwashing was about 20 times a day.
- Example 1 A desalination treatment was performed in the same manner as in Example 1 except that the backwash interval of the filtration membrane module 10 was set to once per hour.
- Example 2 Using the desalination apparatus shown in FIG. 7, an experiment was conducted in which the amount of sodium hypochlorite added was changed according to the backwash interval.
- the backwash interval is about 60 to 120 minutes, the amount of sodium hypochlorite added is 30 mg / L.
- the amount of sodium hypochlorite added is 50 mg / L.
- the washing interval was 120 minutes or more, the amount of sodium hypochlorite added was 20 mg / L. Even when the TOC of the raw water was 1.5 mg / L, the number of backwashes per day was 30 times.
- Example 2 A desalination treatment was performed in the same manner as in Example 2 except that the amount of sodium hypochlorite added was 30 mg / L regardless of the backwash interval. When the TOC of the raw water was 1.5 mg / L, the number of backwashes per day was 40, and contaminants accumulated on the filtration membrane, resulting in an increase in the number of washes compared to Example 2.
- Example 3 A continuous treatment test was carried out with the desalination apparatus shown in FIG. 6 (a mode in which a plurality of filtration membrane modules are provided and controlled by the transmembrane pressure difference and the backwash interval).
- the cleaning (backwashing) conditions of the ultrafiltration membrane of the filtration membrane module 10 were automatic control in which backwashing was performed when the transmembrane pressure difference reached 35 kPa. Further, when the transmembrane pressure did not reach 35 kPa and the time during which backwashing was not performed was 360 minutes, the backwashing was forcibly performed.
- the backwash interval of the filtration membrane module 10 is about 60 to 120 minutes
- the backwash interval of the filtration membrane module 10a is set to 60 minutes
- the backwash interval of the filtration membrane module 10 is 30 to 60 minutes
- the filtration membrane The backwash interval of the module 10a was set to 30 minutes
- the backwash interval of the filtration membrane module 10 was 120 minutes or more
- the backwash interval of the filtration membrane module 10a was set to 90 minutes.
- the operation state of the filtration membrane module 10 was the same as that of Example 1, the operation state of the filtration membrane module 10a was also good, and the initial pressure after backwashing did not increase during the period.
- Example 4 A continuous treatment test was conducted using the desalination apparatus of FIG. The amount of treated water was 10 m 3 / d, and the sand filtration was backwashed at a rate of once / one day to two days. Automatic control was performed in which backwashing was performed when the transmembrane pressure difference of the filtration membrane module 10 (ultrafiltration membrane) reached 35 kPa. Further, when the transmembrane pressure did not reach 35 kPa and the time during which backwashing was not performed was 360 minutes, the backwashing was forcibly performed. A cleaning liquid in which sodium hypochlorite was added to UF permeate so as to be 10 mg / L was used.
- the amount of ferric chloride added in the previous stage was controlled according to the backwash interval of the filtration membrane module 10.
- the backwash interval is about 60 to 120 minutes, the addition amount of ferric chloride is 2.5 mg / L as Fe, and when the backwash interval is changed to 30 to 60 minutes, the addition amount of ferric chloride is Set to 5 mg / L.
- the backwash interval was 120 to 240 minutes, the amount of ferric chloride added was 0 mg / L.
- the average TOC of seawater was 1.0 to 1.5 mg / L, and the number of backwashes was 20 times a day.
- Example 3 A desalination treatment was performed in the same manner as in Example 4 except that the addition amount of ferric chloride was kept constant at 2.5 mg / L.
- the TOC of raw water was 1.0 to 1.5 mg / L, the average number of washings was 30 times.
- the TOC of the raw water was high, the number of washings increased and frequent backwashing was performed, so the average number of washings was higher than that in Example 4.
- Example 5 Seawater was taken using the desalination apparatus shown in FIG. 8, and the desalination process was performed.
- the amount of treated water was 10 m 3 / d, and the sand filtration was backwashed at a rate of once / one day to two days.
- the ultrafiltration membrane was washed (backwashed) under the automatic control in which backwashing was performed when the transmembrane pressure difference reached 40 Pa.
- backwashing was forcibly performed.
- the control valve was opened and closed, and the cleaning liquid to be used was switched.
- Example 5 Automatic control was performed in the same manner as in Example 5 except that only permeated water was used as the cleaning liquid and the cleaning liquid was not switched according to the backwash interval. During operation for about 3 months, the average number of backwashing was about 35 times a day. When the quality of the seawater deteriorated, cleaning was poor, the initial pressure increased, and the frequency of backwashing increased.
- the amount of treated water was 10 m 3 / d, and the sand filtration was backwashed at a rate of once / one day to two days.
- the ultrafiltration membrane was washed (backwashed) under the automatic control in which backwashing was performed when the transmembrane pressure difference reached 40 Pa.
- backwashing was forcibly performed.
- the control valve was opened and closed, and the cleaning liquid to be used was switched.
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Abstract
Description
[1]原水中の溶解性有機物及び濁質分を除去するろ過膜と、逆浸透膜とを備えた淡水化装置における淡水化方法であって、
ろ過膜へ流入する原水の流入圧と、ろ過膜から流出する透過水の流出圧と、を測定して得られる膜間差圧が所定値に達した時もしくは設定時間経過時のいずれか早い時にろ過膜の逆洗を開始するろ過膜の逆洗工程を含む、淡水化方法。
[2]前記ろ過膜の逆洗は、前記ろ過膜を透過した透過水又は前記逆浸透膜を透過した逆浸透膜透過水をそのまま又は加温して、洗浄液として使用することを特徴とする[1]に記載の淡水化方法。
[3]前記膜間差圧が所定値に達するまでの所要時間に応じて、前記ろ過膜を透過した透過水、加温した前記透過水、前記逆浸透膜を透過した逆浸透膜透過水又は加温した前記逆浸透膜透過水のいずれかを選択して、洗浄液として使用することを特徴とする[1]又は[2]に記載の淡水化方法。
[4]前記膜間差圧の所定値は、25kPa~100kPaの範囲で設定し、
前記設定時間は、膜間差圧が所定値に達するまでに要する時間の1倍~10倍の範囲で設定する、[1]~[3]のいずれか1項に記載の淡水化方法。
[5]前記膜間差圧が所定値に達するまでの所要時間に応じて、洗浄液に添加する酸化剤の添加時間及び/又は添加量を制御する、ことをさらに含む[1]~[4]のいずれか1項に記載の淡水化方法。
[6]前記膜間差圧が所定値に達するまでの所要時間に応じて、原水に添加する凝集剤の添加時間及び/又は添加量を制御する、ことをさらに含む[1]~[5]のいずれか1項に記載の淡水化方法。
[7]前記ろ過膜を複数含み、
少なくとも1のろ過膜の膜間差圧を計測し、膜間差圧が所定値に達するまでの所要時間に応じて洗浄間隔を決定し、
当該洗浄間隔に従って、他のろ過膜の逆洗を行う、[1]~[6]のいずれか1項に記載の淡水化方法。
[8]原水中の溶解性有機物及び濁質分を除去するろ過膜と、逆浸透膜とを備えた淡水化装置であって、
当該ろ過膜を内包し、当該ろ過膜へ原水を供給する原水供給管と、当該ろ過膜からの透過水を流出する透過水流出管と、当該ろ過膜へ洗浄液を供給する洗浄液供給管と、当該ろ過膜からの洗浄廃液を流出する洗浄廃液流出管と、が接続されている、ろ過膜モジュールと、
当該原水供給管内の原水の圧力を測定する流入圧計測手段と、
当該透過水流出管内の透過水の圧力を測定する流出圧計測手段と、
当該流入圧計測手段と当該流出圧計測手段とからの各計測結果に基づいて膜間差圧を算出し、当該膜間差圧が所定値に達した時もしくは所定の設定時間経過時のいずれか早い時に、当該ろ過膜モジュールへの洗浄液の供給を開始する制御手段と、
を具備する、淡水化装置。
[9]前記洗浄液供給管には、前記透過水流出管、及び前記逆浸透膜を透過した逆浸透膜透過水を前記ろ過膜モジュールの洗浄液供給管に送る逆浸透膜透過水送水管が接続されており、
当該透過水流出管及び当該逆浸透膜透過水送水管には、それぞれ、流量制御弁が設けられており、
当該流量制御弁は、透過水又は逆浸透膜透過水のいずれかを洗浄液として前記洗浄液供給管に送水するように前記制御手段によって制御される、[8]に記載の淡水化装置。
[10]前記透過水流出管、前記逆浸透膜透過水送水管又は前記洗浄液供給管には、加温手段がされに設けられている、[9]に記載の淡水化装置。
[11]前記洗浄液供給管に接続されている酸化剤添加手段をさらに具備し、
当該酸化剤添加手段は、前記制御手段により、前記膜間差圧が所定値に達するまでの所要時間に応じて、洗浄液に添加する酸化剤の添加時間及び/又は添加量が制御される、[8]~[10]のいずれか1項に記載の淡水化装置。
[12]前記原水供給管に接続されている凝集剤添加手段をさらに具備し、
当該凝集剤添加手段は、前記制御手段により、前記膜間差圧が所定値に達するまでの所要時間に応じて、原水に添加する凝集剤の添加時間及び/又は添加量が制御される、[8]~[11]のいずれか1項に記載の淡水化装置。
[13]前記原水供給管に接続されている砂ろ過槽をさらに具備し、
当該砂ろ過槽によりろ過された原水を前記ろ過膜モジュールに供給する、[8]~[12]のいずれか1項に記載の淡水化装置。
[14]前記ろ過膜モジュールの透過水流出管と前記逆浸透膜との間に設けられた、前記透過水を貯留する透過水貯槽をさらに具備し、
前記洗浄液供給管は、当該透過水貯槽と前記ろ過膜モジュールとの間に設けられている、[8]~[13]のいずれか1項に記載の淡水化装置。
[15]複数の前記ろ過膜モジュールを含み、
前記制御手段は、少なくとも1のろ過膜モジュールの膜間差圧が所定値に達するまでの所要時間に応じて洗浄間隔を決定し、決定された当該洗浄間隔に従って、他のろ過膜モジュールの逆洗を制御する、[8]~[14]のいずれか1項に記載の淡水化装置。
[16]前記原水供給管、前記透過水流出管、前記洗浄液供給管、及び前記洗浄廃液流出管には、前記制御手段によって制御される調節弁が設けられている、[8]~[15]のいずれか1項に記載の淡水化装置。
図7に示す淡水化装置(制御系Cにより弁の開閉のみ制御する態様)を用い、海水を取水し、淡水化処理を行った。
ろ過膜モジュール10の逆洗間隔を1時間に1回に設定した以外は、実施例1と同様に淡水化処理を行った。
図7に示す淡水化装置を用い、逆洗間隔に応じて次亜塩素酸ナトリウムの添加量を変えた実験を行った。逆洗間隔が約60~120分の場合に次亜塩素酸ナトリウムの添加量を30mg/L、逆洗間隔が30~60分の場合に次亜塩素酸ナトリウムの添加量を50mg/L、逆洗間隔が120分以上の場合に次亜塩素酸ナトリウムの添加量を20mg/Lとした。原水のTOCが1.5mg/Lの場合においても1日あたりの逆洗回数は30回であった。
逆洗間隔に関わらず次亜塩素酸ナトリウムの添加量を30mg/Lとした以外は、実施例2と同様に淡水化処理を行った。原水のTOCが1.5mg/Lの場合は、1日あたりの逆洗回数は40回となり、ろ過膜に汚染物が蓄積して、実施例2よりも洗浄回数が増加した。
図6に示す淡水化装置(複数のろ過膜モジュールを具備し、膜間差圧及び逆洗間隔によって制御する態様)で、連続処理試験を実施した。ろ過膜モジュール10の限外ろ過膜の洗浄(逆洗)条件は、膜間差圧が35kPaになった時点で逆洗を実施する自動制御とした。また、膜間差圧が35kPaに達せず逆洗を実施しない時間が360分となった場合には、強制的に逆洗を実施した。ろ過膜モジュール10の逆洗間隔が約60~120分の場合にろ過膜モジュール10aの逆洗間隔を60分に設定し、ろ過膜ジュール10の逆洗間隔が30~60分の場合にろ過膜モジュール10aの逆洗間隔を30分に設定し、ろ過膜モジュール10の逆洗間隔が120分以上の場合にろ過膜モジュール10aの逆洗間隔を90分に設定した。ろ過膜モジュール10の運転状況は実施例1と同様であったが、ろ過膜モジュール10aの運転状況も良好で、期間中逆洗後の初期圧が上昇することは無かった。
図5の淡水化装置を用いて、連続処理試験を実施した。処理水量は10m3/dであり、砂ろ過は1回/1日~2日の割合で、逆洗を行なった。ろ過膜モジュール10(限外ろ過膜)の膜間差圧が35kPaになった時点で逆洗を実施する自動制御とした。また、膜間差圧が35kPaに達せず逆洗を実施しない時間が360分となった場合には、強制的に逆洗を実施した。UF透過水に次亜塩素酸ナトリウムを10mg/Lとなるように添加した洗浄液を用いた。ろ過膜モジュール10の逆洗間隔に応じて、前段の塩化第二鉄の添加量を制御した。逆洗間隔が約60~120分の場合に、塩化第二鉄の添加量をFeとして2.5mg/L、逆洗間隔が30~60分に変動した場合は塩化第二鉄の添加量を5mg/Lに設定した。逆に逆洗間隔が120~240分になった場合は、塩化第二鉄の添加量を0mg/Lとした。海水の平均TOCが1.0~1.5mg/Lに対して、逆洗回数は1日20回であった。
塩化第二鉄の添加量を2.5mg/Lと一定にした以外は実施例4と同様に淡水化処理を行った。原水のTOCが1.0~1.5mg/Lの場合、平均の洗浄回数は30回であった。原水のTOCが高いときには洗浄回数が増加し、頻繁に逆洗がかかったので、実施例4に比較して平均洗浄回数が高くなった。
図8に示す淡水化装置を用いて、海水を取水し、淡水化処理を行った。
洗浄液として透過水のみを使用して逆洗間隔に応じた洗浄液の切り替えを行わなかった以外は、実施例5と同様に自動制御した。約3ヶ月の稼働中、平均的な逆洗回数は1日35回程度であった。海水の水質が悪化した際には、洗浄不良となり、初期圧が上昇し、逆洗頻度が増加した。
図9に示す淡水化装置を用いて、海水を取水し、淡水化処理を行った。
11:洗浄廃液流出管
12:空気供給管
13:原水供給管
14:ドレン
15:透過水流出管
20:ろ過水槽
22:洗浄液供給管
24:分岐管
27:酸化剤添加手段
28:凝集剤添加手段
30:逆浸透膜モジュール
32:逆浸透膜透過水送水管
34:分岐管
40:砂ろ過装置
42:加温槽
44:加温洗浄液返送管
P1:流入圧計測用圧力計(流入圧計測手段)
P2:流出圧計測用圧力計(流出圧計測手段)
C:制御系(制御手段)
V1:洗浄液供給調節弁
V2:洗浄廃液調節弁
V3:透過水調節弁
V4:原水調節弁
V5:流量制御弁
V6:流量制御弁
V7:流量制御弁
Claims (16)
- 原水中の溶解性有機物及び濁質分を除去するろ過膜と、逆浸透膜とを備えた淡水化装置における淡水化方法であって、
ろ過膜へ流入する原水の流入圧と、ろ過膜から流出する透過水の流出圧と、を測定して得られる膜間差圧が所定値に達した時もしくは設定時間経過時のいずれか早い時にろ過膜の逆洗を開始するろ過膜の逆洗工程を含むことを特徴とする淡水化方法。 - 前記ろ過膜の逆洗は、前記ろ過膜を透過した透過水又は前記逆浸透膜を透過した逆浸透膜透過水をそのまま又は加温して、洗浄液として使用することを特徴とする請求項1に記載の淡水化方法。
- 前記膜間差圧が所定値に達するまでの所要時間に応じて、前記ろ過膜を透過した透過水、加温した前記透過水、前記逆浸透膜を透過した逆浸透膜透過水又は加温した前記逆浸透膜透過水のいずれかを選択して、洗浄液として使用することを特徴とする請求項1又は2に記載の淡水化方法。
- 前記膜間差圧の所定値は、25kPa~100kPaの範囲で設定し、
前記設定時間は、膜間差圧が所定値に達するまでに要する時間の1倍~10倍の範囲で設定することを特徴とする請求項1~3のいずれか1項に記載の淡水化方法。 - 前記膜間差圧が所定値に達するまでの所要時間に応じて、洗浄液に添加する酸化剤の添加時間及び/又は添加量を制御する、ことを含むことを特徴とする請求項1~4の何れか1項に記載の淡水化方法。
- 前記膜間差圧が所定値に達するまでの所要時間に応じて、原水に添加する凝集剤の添加時間及び/又は添加量を制御する、ことをさらに含むことを特徴とする請求項1~5のいずれか1項に記載の淡水化方法。
- 前記ろ過膜を複数含み、
少なくとも1のろ過膜の膜間差圧を計測し、膜間差圧が所定値に達するまでの所要時間に応じて洗浄間隔を決定し、
当該洗浄間隔に従って、他のろ過膜の逆洗を行うことを特徴とする請求項1~6のいずれか1項に記載の淡水化方法。 - 原水中の溶解性有機物及び濁質分を除去するろ過膜と、逆浸透膜とを備えた淡水化装置であって、
当該ろ過膜を内包し、当該ろ過膜へ原水を供給する原水供給管と、当該ろ過膜からの透過水を流出する透過水流出管と、当該ろ過膜へ洗浄液を供給する洗浄液供給管と、当該ろ過膜からの洗浄廃液を流出する洗浄廃液流出管と、が接続されている、ろ過膜モジュールと、
当該原水供給管内の原水の圧力を測定する流入圧計測手段と、
当該透過水流出管内の透過水の圧力を測定する流出圧計測手段と、
当該流入圧計測手段と当該流出圧計測手段とからの各計測結果に基づいて膜間差圧を算出し、当該膜間差圧が所定値に達した時もしくは設定時間経過時のいずれか早い時に、当該ろ過膜モジュールへの洗浄液の供給を開始する制御手段と、
を具備することを特徴とする、淡水化装置。 - 前記洗浄液供給管には、前記透過水流出管、及び前記逆浸透膜を透過した逆浸透膜透過水を前記ろ過膜モジュールの洗浄液供給管に送る逆浸透膜透過水送水管が接続されており、
当該透過水流出管及び当該逆浸透膜透過水送水管には、それぞれ、流量制御弁が設けられており、
当該流量制御弁は、透過水又は逆浸透膜透過水のいずれかを洗浄液として前記洗浄液供給管に送水するように前記制御手段によって制御されることを特徴とする請求項8に記載の淡水化装置。 - 前記透過水流出管、前記逆浸透膜透過水送水管又は前記洗浄液供給管には、加温手段がされに設けられていることを特徴とする請求項9に記載の淡水化装置。
- 前記洗浄液供給管に接続されている酸化剤添加手段をさらに具備し、
当該酸化剤添加手段は、前記制御手段により、前記膜間差圧が所定値に達するまでの所要時間に応じて、洗浄液に添加する酸化剤の添加時間及び/又は添加量が制御されることを特徴とする請求項8~10のいずれか1項に記載の淡水化装置。 - 前記原水供給管に接続されている凝集剤添加手段をさらに具備し、
当該凝集剤添加手段は、前記制御手段により、前記膜間差圧が所定値に達するまでの所要時間に応じて、原水に添加する凝集剤の添加時間及び/又は添加量が制御されることを特徴とする請求項8~11のいずれか1項に記載の淡水化装置。 - 前記原水供給管に接続されている砂ろ過槽をさらに具備し、
当該砂ろ過槽によりろ過された原水を前記ろ過膜モジュールに供給することを特徴とする請求項8~12のいずれか1項に記載の淡水化装置。 - 前記ろ過膜モジュールの透過水流出管と前記逆浸透膜との間に設けられた、前記透過水を貯留する透過水貯槽をさらに具備し、
前記洗浄液供給管は、当該透過水貯槽と前記ろ過膜モジュールとの間に設けられていることを特徴とする請求項8~13のいずれか1項に記載の淡水化装置。 - 複数の前記ろ過膜モジュールを含み、
前記制御手段は、少なくとも1のろ過膜モジュールの膜間差圧が所定値に達するまでの所要時間に応じて洗浄間隔を決定し、決定された当該洗浄間隔に従って、他のろ過膜モジュールの逆洗を制御することを特徴とする請求項8~14のいずれか1項に記載の淡水化装置。 - 前記原水供給管、前記透過水流出管、前記洗浄液供給管、及び前記洗浄廃液流出管には、前記制御手段によって制御される調節弁が設けられていることを特徴とする請求項8~15のいずれか1項に記載の淡水化装置。
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WO2021260080A1 (fr) * | 2020-06-26 | 2021-12-30 | Fgwrs | Dispositif compact de filtration d'eau |
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US11602718B2 (en) | 2017-04-26 | 2023-03-14 | Bl Technologies, Inc. | High recovery integrated UF/RO system |
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