Technical field
[0001]
The present invention, for example, sea water on water treatment method and a water treatment system for processing desalination.
BACKGROUND
[0002]
Water treatment system seawater processing desalination comprises a desalination treatment apparatus using a reverse osmosis membrane or the like. Water treatment system for suppressing the performance degradation due to contamination of a reverse osmosis membrane desalination apparatus, upstream of the desalination apparatus, particulate matter in sea water, as a pretreatment section of filtration apparatus for filtering bacteria like It is provided.
[0003]
When utilizing a water treatment system, sometimes quality variation of the treated water after filtration will awake. Then, since contaminate the reverse osmosis membrane desalination apparatus, there filtration performance must be stable in the pretreatment unit.
[0004]
　Patent Document 1, previously provided with a plurality of filtering devices as a pretreatment unit, when the filtration performance of the filtration apparatus decreases, configured to switch the flow path between a plurality of filtration apparatus is disclosed. According to such a configuration, when the filtration performance is lowered, switching the channel, by filtration performance by cleaning or replacement of the filter of the filtration apparatus decreases, to stabilize the water quality after the filtration.
CITATION
Patent Document
[0005]
Patent Document 1: JP 2014-221459 JP
Summary of the Invention
Problems that the Invention is to Solve
[0006]
　Incidentally, in the water treatment system, by variations in the seawater is treated water, sometimes quality variations of the water to be treated takes place after filtration. The variation of such seawater, for example, there are fluctuations in the seawater temperature.
　However, if the variation of seawater falls within, of the water to be treated water quality also returns to the original. Therefore, in the configuration disclosed in Patent Document 1, it can not cope with the case where water quality variation after filtration due to such a variation in seawater occurs.
　This invention has been made in view of the above circumstances, and provides a water treatment method and a water treatment system which can suppress variation of an even be filtered water if quality variations of the water to be treated has occurred.
Means for Solving the Problems
[0007]
　The present invention for solving the above problems, adopts the following means.
　According to a first aspect of the invention, the water treatment method, water quality acquisition step of acquiring quality evaluation value of the water to be treated to filtration treatment before it has been subjected to desalting treatment, the obtained said quality evaluation value when the value becomes a predetermined threshold value or more, including a filtration rate changing step of lowering the reference speed the filtration rate of the water to be treated.
[0008]
　Thus, when the water quality evaluation value of treated water filtration process has been performed becomes a predetermined threshold value or more, reducing the filtration rate of the water to be treated from the reference speed, improved water quality after filtration. Therefore, if the quality fluctuations of the water to be treated has occurred, it is possible to water quality after the filtration can be suppressed from being lowered.
[0009]
　According to a second aspect of the invention, the water treatment method, water treatment method of the first aspect, the filtration rate change process, with increasing number of the filtration device treated water is passed through a plurality by each water passage said diverted water to be treated in the filtration apparatus, it may be decreasing the filtration rate in each one of the filtering device.
　With this configuration, by increasing the number of filtering devices that passed through the treated water, reducing the filtration rate of every single filtration device, reducing the processing amount of water across the plurality of filtering devices it can be suppressed to. Thus, while suppressing the reduction of the amount of water treated, it is possible to suppress variations in water quality after filtration.
[0010]
　According to a third aspect of the invention, the water treatment method, the water treatment method of the first or second aspect, wherein the filtering process, the water to be treated sequentially through water filtration device in a plurality of stages, the filter speed changing step may be configured to lower than the filtration rate of the filtering apparatus of the second stage after the filtration rate of the filtration device in the first stage.
　With this configuration, by reducing the filtration rate in the filtration apparatus of the first stage, the filtration device after the second stage, the treatment water is sent with improved water quality after filtration is the filtration device in the first stage It is. Therefore, the filtration device after the second stage is less affected by quality variations of the water to be treated before filtration, it is possible to perform filtration in a stable quality.
[0011]
　According to a fourth aspect of the invention, the water treatment method, in a third aspect, at least a portion of said filter device subsequent second stage plurality arranged in parallel, the filtration rate change process, the second stage or later of the plurality of the filtering devices arranged in parallel, and a portion of the filtering device, by each passing water divert the water to be treated and the filtering apparatus of the first stage, the said first stage the filtration rate of the treated water that passed through the filtration apparatus may be reduced.
　In this manner, by a portion of the filtering device, by diverting the water to be treated and the filtration device of the first stage through the water of a plurality of filtration devices arranged in parallel after the second stage, the first stage it is possible to increase the number of the filtering device. Thus, by using as the first stage of the filtering device the part of the filtration device of the plurality of filtration devices arranged in parallel after the second stage, there is no need to provide a preliminary filtration apparatus.
[0012]
　According to a fifth aspect of the invention, the water treatment method, and in any one of aspects from the first fourth aspect, in a state in which reduced the filtration rate, the threshold above which the quality evaluation value is predetermined when becomes, the filtration rate may be returned to the reference speed.
　With this configuration, when the water quality fluctuations in the water to be treated before filtration has subsided, by undoing the filtration rate was lowered, to perform a good filtration efficiency in accordance with the water quality of the water to be treated can.
[0013]
　According to a sixth aspect of the invention, the water treatment system includes a processing unit having a filtering device for performing filtering processing to the water to be treated passed through the treated water in which the filtration process is applied and concentrated water displaying a reverse osmosis unit for separating the freshwater, a detector for detecting the water quality evaluation value of the water to be treated between the said processing unit and said reverse osmosis membrane apparatus, the information based on the quality evaluation value a display unit, and an operator-operable operating unit, based on the operation signal sent by the operation of the operation unit is performed in accordance with the information displayed on the display unit, the object to be processed in said filtration apparatus comprising a filtration rate adjusting unit that reduces the filtration rate of the water.
　According to such a water treatment system, After filtration of the treated water in the processing unit, by separating into a concentrated water and fresh water in the reverse osmosis membrane apparatus can be subjected to a desalination process of the water to be treated. In this water treatment system, before passing the water to the reverse osmosis unit, detected by the detecting unit water quality evaluation value of the treated water after filtration treatment. Information based on the detected quality evaluation value, for example, water quality evaluation value itself or as quality determination result of the water quality evaluation value, etc., is displayed on the display unit. The operator can look at the information displayed on the display unit, to determine whether it is necessary to adjust the filtration speed. Result of the determination, if necessary to adjust the filtration speed, the operator inputs a predetermined operation on the operation unit. Then, the operation unit transmits the operation signal corresponding to operation by the operator. Filtration rate adjustment unit may be based on the operation signal sent from the operation unit, lowering the filtration rate of the water to be treated in the filtration system.
　In this way, when the water quality of treated water filtration process has been performed is decreased, by reducing the filtration rate of the water to be treated, thereby improving water quality after the filtration in the filtration apparatus. Therefore, if the quality fluctuations of the water to be treated has occurred, it is possible to prevent the water quality after the filtration resulting in excessive reduction.
[0014]
　According to a seventh aspect of the invention, the water treatment system includes a processing unit having a filtering device for performing filtering processing to the water to be treated passed through the treated water in which the filtration process is applied and concentrated water a reverse osmosis unit for separating the fresh water, and the detector for detecting the water quality evaluation value of the water to be treated between the said processing unit and said reverse osmosis membrane apparatus, the threshold value of the quality evaluation value is predetermined when equal to or more than, and a filtration rate adjusting unit that reduces the filtration rate of the water to be treated in the filtration system.
　According to such a water treatment system, before passing the water to the reverse osmosis unit, detected by the detecting unit water quality evaluation value of the treated water after filtration treatment. If the detected water quality evaluation value if equal to or greater than the predetermined threshold value, the filtration rate adjustment unit reduces the filtration rate of the water to be treated in the filtration system.
　In this way, when the water quality of treated water filtration process has been performed is decreased, by automatically lowering the filtration rate of the water to be treated, thereby improving water quality after the filtration in the filtration apparatus. Therefore, if the quality fluctuations of the water to be treated has occurred, it is possible to water quality after the filtration can be suppressed from being lowered.
[0015]
　According to an eighth aspect of the invention, the water treatment system in the sixth or seventh aspect, wherein the processing unit, a filtration unit group including a plurality of filtration devices arranged in parallel with each other, to the filtration device has a first switching unit for switching the water flow and non-water flow, and the filtration rate adjusting unit, the filtration device treated water is passed through at the filtration apparatus group by switching the first switching unit by increasing the number of, it may be reduce the filtration rate.
　With this configuration, while increasing the number of filtering devices that passed through the treated water, reducing the filtration rate of every single filtration device, reducing the processing amount of water across the plurality of filtering devices it can be suppressed to. Thus, while suppressing the reduction of the amount of water treated, it is possible to suppress variations in water quality after filtration.
[0016]
　According to a ninth aspect of the invention, the water treatment system, in any one aspect from the sixth eighth aspect, wherein the processing unit, a filtration unit group including a plurality of filtration devices arranged in parallel with each other together with the filtration device group, provided in a plurality of stages in series with one another, wherein the processing unit, the second stage or later of the filtering device group portion of the filtering device is a filtration device the filtration device group in the first stage having a second switching unit that switches to be connected in parallel to, the filtration rate adjusting unit, by switching the second switching unit increases the number of the filtering device of the filtering unit group in the first stage it is, may be decreasing the filtration rate in the filtration apparatus of the filtration unit group in the first stage.
　With this configuration, a portion of the filter of the filtration device group after the second stage, by connecting in parallel to the filtering device of the first stage, increasing the number of the first stage of the filter can. In this manner, by using as the first stage of the filtering device the part of the filtration device of the plurality of the filter after the second stage, there is no need to provide a preliminary filtration apparatus.
　In particular, by lowering the filtration rate in the first stage of the filtration apparatus, it is possible to improve the filtration performance, in the filtration device after the second stage is less susceptible to quality variation of the water to be treated before filtration, a stable water it is possible to perform filtration.
Effect of the invention
[0017]
　According to the above-described water treatment method and a water treatment system, it is possible to suppress the fluctuation of the filtration water even when the water quality fluctuations in the water to be treated has occurred.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018]
FIG. 1 is a diagram showing the overall configuration of a water treatment system according to an embodiment of the present invention.
2 is a diagram showing the structure of the preprocessing section of the water treatment system according to the first embodiment.
Is a diagram showing the flow of the water treatment method in [3] the pre-processing unit.
4 is a diagram showing the water flow condition of the pre-processing unit in the state with reduced filtration rate.
[5] when the filtration rate is varied, a graph showing changes in water quality evaluation value after filtration.
6 is a diagram showing a configuration of a pre-processing unit in the first modification of the first embodiment.
[7] and the filtration rate is constant in the sand filtration apparatus of the first stage, when changing the filtration rate of the sand filtration apparatus of the second stage, the change of water quality evaluation value after filtration in sand filtration apparatus of the second stage is a diagram illustrating a.
8 is a diagram showing the configuration of a pre-processing unit in a second modification of the first embodiment.
9 is a diagram showing the configuration of a pre-processing unit in the second embodiment of the water treatment method and a water treatment system.
In [10] the pre-processing unit is a diagram showing the water flow conditions in a state that suppresses the filtration rate.
DESCRIPTION OF THE INVENTION
[0019]
　It will be described below with reference to water treatment method and a water treatment system according to an embodiment of the invention with reference to the drawings.
(First Embodiment)
　FIG. 1 is a diagram showing the overall configuration of the water treatment system of this embodiment.
　As shown in FIG. 1, the water treatment system 10 of this embodiment includes a preprocessing unit 20, a cartridge filter 30, a high pressure pump 40, and a desalination unit 50, an energy recovery device 60, the .
[0020]
　Preprocessing section 20, intake seawater is fed through the intake pipe P1 by intake pump (not shown). Preprocessing section 20, the fed seawater (water to be treated), water flow prior to desalination unit 50, before the desalting is performed by the desalination process unit 50 in other words, to a filtration treatment, seawater to remove suspended substances in. In this embodiment, as a pre-processing unit 20, using a sand filtration device (filtration device) 21, without turned such as flocculants and pH adjusting agent, it performs so-called Mukusuri Note pretreatment.
　Sand filtration device 21 includes one or more stages of the filter unit (filter material layer) 21f. In this embodiment, the sand filtration system 21 includes a filter portion 21f of the two-stage. Filter unit 21f is a filter medium, and a predetermined amount of sand (not shown), biofilm grown and maintained on the surface of the sand and (not shown), a. Filter unit 21f is a biofilm, SDI or stains desalination unit 50 (Silt Dencity Index: dirty index) component, to remove the cause of biofouling BOD (Biological Oxygen Demand) components and the like. The filter unit 21f is the sand to remove fines component contained in seawater.
[0021]
　Cartridge filter 30, on the downstream side of the pretreatment unit 20 are connected via the connecting pipe P3. Cartridge filter 30, were not removed by the pre-processing unit 20, for example, 1 ~ 5 [mu] m about fine foreign matter so as not to enter the high-pressure pump 40, removing foreign matter on a given diameter or.
[0022]
　High-pressure pump 40, the downstream side of the cartridge filter 30, are connected via a connecting pipe P4. High-pressure pump 40, sea water passing through the cartridge filter 30, and raised to a predetermined pressure is fed into the desalination unit 50 through the connection pipe P5.
[0023]
　Desalination unit 50 performs desalted. Here, the desalting treatment, for example, remove salts in seawater, or a process of concentrating. Desalination unit 50 in this embodiment, for example, using a reverse osmosis membrane F, to remove ionic components from seawater. In this embodiment, as desalination unit 50, a seawater reverse osmosis membrane (Sea Water Reverse Osmosis Membrane) processing unit (reverse osmosis unit) 51, brackish water for reverse osmosis membrane (Brackish Water Reverse Osmosis Membrane) processor ( It includes a reverse osmosis unit) 52, a.
[0024]
　Seawater reverse osmosis membrane treatment apparatus 51 on the downstream side of the high-pressure pump 40 are connected via a connecting pipe P5. Seawater reverse osmosis membrane treatment apparatus 51, the seawater is pressurized by a high pressure pump 40, via the connecting pipe P5 is passed through the reverse osmosis membrane F, obtain permeated water salinity (ionic components) have been removed. The resulting permeate is fed into the brackish water for reverse osmosis membrane treatment apparatus 52 through a connecting pipe P6. Concentrated water containing ion components removed in the seawater reverse osmosis membrane treatment apparatus 51 is sent to the energy recovery device 60 via the connection pipe P7. Concentrated water passing through the energy recovery device 60 is drained to the outside (sea) via a drain pipe P8.
[0025]
　Brackish water for reverse osmosis membrane treatment apparatus 52, the downstream side of the seawater reverse osmosis membrane treatment apparatus 51 are connected via a connecting pipe P6. Brackish water for reverse osmosis membrane treatment apparatus 52, by passing the permeate through the seawater reverse osmosis membrane treatment apparatus 51 to the reverse osmosis membrane F, to further remove the ion components, to obtain pure water. The resulting pure water, via the supply pipe P9, is supplied to the water tank (not shown) or the like. Here, in the case where pure water obtained a beverage or the like, the addition of minerals turned portion P10 provided in the supply pipe P9. Concentrated water containing ion components removed in brackish water for reverse osmosis membrane treatment apparatus 52 is discharged to the drain pipe P8 via a drain pipe P11, and is discharged to the outside (sea).
[0026]
　Energy recovery device 60 recovers the energy from the concentrated water discharged from the seawater reverse osmosis membrane treatment apparatus 51. Concentrated water discharged from the seawater reverse osmosis membrane treatment apparatus 51 is pressurized by the high pressure pump 40. Energy recovery device 60 is provided with a rotor (hydraulic turbine) 61 that is rotated by water flow concentrated water fed from the connection pipe P7. The rotor 61, with the rotational energy by pressurized concentrated water rotates the rotor 62 which is integrally connected to the rotor 61. Downstream of the cartridge filter 30, the branch pipe P12 is provided to branch from the connecting pipe P4. Some of the seawater passed through the cartridge filter 30 is fed into the seawater reverse osmosis membrane treatment apparatus 51 by the rotor 62 through the energy recovery device 60 through the branch pipe P12. Thus, as part of the energy feeding the seawater seawater reverse osmosis membrane treatment apparatus 51, it is possible to use energy of concentrated water recovered by the energy recovery device 60.
[0027]
　Figure 2 is a diagram showing the configuration of a preprocessing unit of the water treatment system.
　As shown in FIG. 2, the pre-processing unit 20 includes a plurality of sand filtration device 21, a detection unit 25, a display unit 26, an operation unit 27, a filtration rate adjustment section 28, the.
[0028]
　In this embodiment, the sand filtration system 21 includes a plurality of (two in the example of FIG. 2) are provided in parallel. One filtration device (filtration device) 21A is always seawater is passed through the intake pipe P1. Other filtration device (filtration device) 21B is the intake pipe P1, and is connected via an on-off valve (first switching unit) V1. Closing valve V1 is normal is closed, the water flow to the sand filter apparatus 21B is not performed.
[0029]
　Detector 25 detects the water quality evaluation value of the sea water between the pre-processing unit 20 and the seawater reverse osmosis membrane treatment apparatus 51. The quality evaluation value for detecting, for example, SDI (Silt Dencity Index: water quality indicators that are involved in occlusion of water treatment film), BFR (Biofilm Formation Rate: biofilms water treatment membrane surface the risk of (biofilm) water index for evaluating), bacterial count (the number of bacteria present in the sample water), ATP (Adenosine Tri-Phoshate : all energetic materials present in the organism), TOC (total organic carbon (total organic carbon): all of the organics carbon content), AOC (assimilable organic carbon: biological assimilation (assimilation) available carbon amount of organic matter), COD (Chemical Oxygen Demand: oxidizing agent (potassium peroxide permanganate, dichromate oxidation By um), the amount of oxygen organic matter is consumed when it is degraded), BOD (Biological Oxygen Demand: The amount of oxygen consumed when the organisms decompose organic matter), FT-IR (Fourier Transform - Infrared spectrometer there are (Fourier transform infrared spectrophotometer)) by the detection of organic substances peculiar structure, the absorption amount of UV absorption (Ultra Violet by organic matter (ultraviolet light)) or the like.
　Detector 25 detects at least one of the water quality value as described above. Detection of water quality evaluation value, a sensor or the like provided in the preprocessing section 20 and the connecting pipe P3 between the seawater reverse osmosis membrane treatment apparatus 51 may be performed by the sensor. Detection of water quality evaluation values, In addition, the sample was sampled from the inside of the connecting pipe P3 between the preprocessing unit 20 and the seawater reverse osmosis membrane treatment apparatus 51 may be performed separately detection work.
[0030]
　The display unit 26 displays information based on the quality evaluation value. Display unit 26, the information based on the quality evaluation value, for example, can be water quality value itself or the water quality evaluation value is displayed as a determination result of the quality of such whether a predetermined threshold value or more.
[0031]
　Operation unit 27, the operator consists operable various switches and the like. Operator, is displayed on the display unit 26, depending on the information based on the quality evaluation value, operating the operation unit 27. Operation unit 27 sends a predetermined operation signal in response to operation of the operator.
[0032]
　Filtration rate adjusting unit 28 based on the operation signal sent from the operation unit 27 adjusts the filtration rate of the seawater in the sand filtration apparatus 21.
[0033]
　Next, a description will be given water treatment method in the pre-processing unit 20 described above.
　Figure 3 is a diagram showing the flow of the water treatment method in the preprocessing unit. Figure 4 is a diagram showing the water flow condition of the pre-processing unit in the state with reduced filtration rate.
(Water Quality acquiring step)
　as shown in FIG. 3, in the pre-processing unit 20 first acquires the detection unit 25 to the water quality evaluation value of seawater filtering process is performed by the sand filtration apparatus 21A (step S1).
[0034]
　The operator checks the information based on the quality evaluation value to be displayed on the display unit 26 determines the acceptability of the quality of seawater filtering process is performed (step S2).
[0035]
(Filtration speed changing step)
　As a result, the water quality evaluation value, unless a predetermined threshold value or more, the flow returns to step S1.
　On the other hand, sea water quality deteriorates, the water quality evaluation value is not less than a predetermined threshold value, the operator performs a predetermined operation on the operation unit 27. Then, the filtration rate adjusting unit 28 based on the operation signal sent from the operation unit 27, lowering the filtration rate of the seawater in the sand filtration apparatus 21 from the reference speed (step S3).
　To reduce the filtration rate, opening the on-off valve V1. Then, as shown in FIG. 4, seawater is fed into the pre-processing unit 20 through the intake tube P1 is shunted to the sand filtration apparatus 21A, it is passed through both of 21B. As a result, the sand filtration apparatus 21A, in each of 21B, the filtration rate drops to 50%.
　At this time, the sand filtration apparatus 21A, in each of 21B, although filtration rate drops to 50%, two sand filtration apparatus 21A, for filtering the seawater 21B, remains unchanged filtration treatment of the whole.
[0036]
　Here, FIG. 5, when varying the filtration rate is a graph showing changes in water quality evaluation value after filtration. In FIG. 5, the horizontal axis is the filtration rate (filtration velocity). The vertical axis of the SDI value when changing the filtration rate in the range of 5 ~ 15 m / H, which is the difference with respect to SDI value (reference value) in the filtration rate 10 m / H.
　As shown in FIG. 5, lowering the filtration rate, SDI value is smaller than the reference value (10m / H). That is, lowering the filtration rate, water quality after the filtration is improved.
　Therefore, the sand filtration apparatus 21A, in each of 21B is the filtration rate, by decreasing than the filtration rate of the normal time in the sand filtration apparatus 21A, it is possible to improve the filtration performance.
[0037]
　Even after the filtration rate decreased from the reference speed, at a predetermined timing, sand filtration apparatus 21A, filtration treatment with 21B acquires the detection unit 25 to the water quality evaluation value of the sea water which has been subjected (step S4).
[0038]
　The operator checks the information based on the quality evaluation value to be displayed on the display unit 26 determines the acceptability of the quality of seawater filtering process is performed (step S5).
[0039]
(Filtration speed changing step)
　As a result, the water quality evaluation value is equal to or remains above a predetermined threshold value, the flow returns to step S4.
　On the other hand, the water quality evaluation value, a case in which it is in a lower than a predetermined threshold value, closing the on-off valve V1, returning the filtration rate of the seawater to the reference speed in the sand filtration apparatus 21A which has lowered (step S6) .
[0040]
　Therefore, according to the water treatment method and a water treatment system of the first embodiment described above, when the water quality evaluation value of seawater filtering process has been performed becomes a predetermined threshold value or more, the filtration rate of the seawater from the reference speed decrease. This improves the water quality after the filtration. Therefore, if the quality change of marine occurs, it is possible to prevent the water quality after the filtration resulting in excessive reduction.
　Also, filtering processing, the filter unit 21f, carried out in the sand filtration apparatus 21 using the filter medium layer biofilm is formed.
　The sand filtering apparatus 21, without any introduced such as flocculants and pH adjusting agents, water quality change of marine susceptible influence the stability of the filtration performance is. However, when performing filtering processing in the sand filtration apparatus 21, by lowering the filtration rate when the quality change of marine occurs as described above, it is possible to effectively stabilize the filtration performance.
[0041]
　Furthermore, the filtration rate changing step, along with increasing the number of the sand filtration apparatus 21 seawater is passed through, seawater is a shunted by passing water to a plurality of sand filtration apparatus 21, one by one sand reducing the filtration rate in the filtration device 21. This makes it possible to process water across the plurality of sand filtration apparatus 21 suppressed to reduce. Thus, while suppressing the reduction of the amount of water treated in the pretreatment unit 20, it is possible to suppress the fluctuation of the water quality after the filtration.
　Thus, according to the water treatment method and a water treatment system 10 described above, even when the quality change of marine occurs, it is possible to suppress the variation of the filtration water.
[0042]
(First modification of first embodiment)
　FIG 6 is a diagram showing the configuration of a pre-processing unit in the first modification of the first embodiment.
　As shown in FIG. 6, the preprocessing section 20, the sand filtration apparatus 21A, on the downstream side of the 21B, sand filtration device (filtration device) 21C may be provided in series.
[0043]
　In such pre-processing unit 20, the filtration process is carried out a sand filtration apparatus 21A and 21B in a plurality of stages arranged in series, in the sand filtration apparatus 21C, by sequentially passing water seawater. When the water quality evaluation value of the filtration process is performed seawater becomes a predetermined threshold value or more, opening the on-off valve V1. Then, seawater is fed into the pre-processing unit 20 through the intake tube P1, first, the upstream side of the sand filtration apparatus 21A, is passed through both of 21B. As a result, the sand filtration apparatus 21A, in each of 21B, the filtration rate drops to 50%.
　Sand filtration apparatus 21A, the treated water that has been filtered through 21B are passed through and joins the downstream side of the sand filtration apparatus 21C. Accordingly, the downstream side of the sand filtration apparatus 21C, the filtration rate is not lowered.
[0044]
　In this manner, by reducing the upstream side in a first stage of the sand filtration apparatus 21A, the filtration rate in 21B, the sand filtration apparatus 21C of the downstream side, the front side of the sand filtration apparatus 21A, the water quality after the filtration at 21B seawater is sent to but improved. Accordingly, the downstream side of the sand filtration apparatus 21C, less susceptible to quality fluctuations in the seawater before filtration, it is possible to perform filtration in a stable quality.
[0045]
　In the preprocessing section 20, the first stage of sand filtration apparatus 21A, on the downstream side of the 21B, but so as to provide a sand filtration device 21C of the second stage in series, and further, after the third stage the sand filtration apparatus it may be provided in series.
[0046]
　Figure 7 is a constant filtration rate sand filtration apparatus of the first stage, when changing the filtration rate of the sand filtration apparatus of the second stage, the change of water quality evaluation value after filtration in sand filtration apparatus of the second stage is a diagram illustrating a.
　Here, the first stage by providing a sand filtering apparatus 21A, the second stage is provided with two sand filtration device 21 arranged in parallel. Sand filtration apparatus 21A of the first stage is a filtration rate was fixed at 12m / H, the second stage of the sand filtration apparatus 21, to secure the filtration rate of one of the sand filtration apparatus 21 to 12m / H, the other sand filtration the filtration rate of the device 21 was changed to 5 ~ 18m / H. In this case, the other of the filtered water in the sand filtration system 21 water quality (SDI), and assess differences for water (SDI) of the water filtered through one sand filtration device 21.
　As a result, the second stage of the sand filtration apparatus 21, unlike the first-stage sand filter apparatus 21 described above, a small influence on the quality of the water was also filtered by changing the filtration rate. Results at varying first stage of these and 2-stage flow velocity respectively is believed to function in the first stage of the filter 21A and the second stage of the filtration device 21B is caused to vary. That is, the filtration device 21A of the first stage is mainly the function as filtration through biofilm, for the second stage of the filter 21B functional physical filtration is the main, in the filtering device of the first stage filtration result the flow rate was varied and the results of changing the filtration flow rate in filtration apparatus of the second stage is considered to be different.
[0047]
(Second modification of the first embodiment)
　FIG. 8 is a diagram showing the configuration of a pre-processing unit in a second modification of the first embodiment.
　As shown in FIG. 8, the pre-processing unit 20, a detection unit 25 which detects the water quality evaluation value of the sea water between the pre-processing unit 20 and the seawater reverse osmosis membrane treatment apparatus 51 (see FIG. 1), filtered comprises a speed adjustment unit 28B, the.
[0048]
　In this second modification, the filtration rate adjustment unit 28B is the information of water quality evaluation value detected by the detection unit 25 receives from the detecting unit 25 by an electrical signal. Filtration rate adjustment unit 28B, when the value of the quality evaluation value becomes a predetermined threshold value or more, as in the first embodiment, the sand filtration apparatus 21A, reducing the filtration rate of the seawater in 21B. That is, as the first embodiment, there is no need to intervention operator.
[0049]
　In this manner, when the quality of seawater filtering process has been performed is decreased, by automatically lowering the filtration rate of the seawater, sand filtration apparatus 21A, the water quality after the filtration in 21B improved. Therefore, lowering the rapid filtration rate when the water quality change of marine occurs can be suppressed water quality after the filtration resulting in excessive reduction.
[0050]
(Second Embodiment)
　Next, a description is given of a second embodiment of such a water treatment method and a water treatment system in the present invention. In the second embodiment described below, only the configuration of the first embodiment and the pre-processing unit are different, with will be denoted by the same reference numerals in the first embodiment and the same parts, the whole of the water treatment system 10 configuration and the like, the duplicated description thereof is omitted.
　Figure 9 is a diagram showing the configuration of a pre-processing unit in the second embodiment of the water treatment method and a water treatment system. 10, in the pre-processing unit in the second embodiment of the water treatment method and a water treatment system, showing a state that suppresses the filtration rate.
　As shown in FIG. 9, the pre-processing unit 20 in this embodiment (processing unit), a plurality of sand filtration device (filtration device) arranged in parallel with one another 21D, 21E, includes a filtration apparatus group R containing 21F there. Furthermore, the preprocessing section 20, the sand filtration apparatus 21D, 21E, a plurality of stages filtration device group (two-stage in the example of FIG. 9) R1, R2 respectively including 21F, are provided in series in the longitudinal.
[0051]
　Preprocessing section 20, a portion of the sand filtration apparatus 21D on the downstream side of the filter group R2 is, sand filtration apparatus 21D of the filter group R1 of the upstream side, 21E, on-off valve which switches to be connected in parallel to 21F and (second switching unit) has a V11 ~ V14.
[0052]
　Off valve V11 is provided in the connecting pipe P21 for connecting the sand filtration apparatus 21D of the filter group R1 of the upstream side, between the sand filtration apparatus 21D of the filter subunit R2 downstream.
　Off valve V12 is provided in the connecting pipe P22 for connecting the sand filtration apparatus 21D on the downstream side of the filter group R2, and a connecting pipe P3.
[0053]
　Off valve V13 is provided in parallel connection pipe P24. Furthermore, the on-off valve V14 is provided in parallel connection pipe P25.
　Parallel connection pipe P24 and parallel connection pipe P25 connects a sand filtration device 21D on the downstream side of the filter group R2 sand filtration apparatus 21D of the filter group R1 of the upstream side, 21E, in parallel with 21F.
　Parallel connection pipe P24 is sand filtration apparatus 21D of the filter group R1 of the upstream side, 21E, branched from the upstream side of 21F, is connected to the upstream side of the sand filtration apparatus 21D on the downstream side of the filter group R2 .
　Parallel connection pipe P25 from the downstream side of the sand filtration apparatus 21D on the downstream side of the filter group R2, sand filtration apparatus 21D of the filter group R1 of the upstream side, 21E, downstream of 21F (e.g., connection pipe P23) to It is connected so as to merge.
[0054]
　In such pre-processing unit 20, a normal state, should the on-off valve V13, V14 and closed. Then, intake seawater from intake tube P1 is sand filtration apparatus 21D of the filter group R1 of the upstream side, 21E, is passed through shunts to 21F. Sand filtration apparatus 21D of the filter group R1 of the upstream side, 21E, filtered water that has been filtered through 21F, the sand filtration apparatus 21D of the filter subunit R2 respectively downstream, 21E, is further filtered through 21F.
[0055]
　In the pre-processing unit 20, when the quality of seawater filtering process has been performed is decreased, similarly to the flow shown in FIG. 3, decreases the filtration rate of the seawater.
(Water acquisition step)
　In other words, in the preprocessing unit 20 first acquires the detection unit 25 to the water quality evaluation value of seawater filtering process has been performed by the filtering unit group R1, R2 (step S1).
[0056]
　The operator checks the information based on the quality evaluation value to be displayed on the display unit 26 determines the acceptability of the quality of seawater filtering process is performed (step S2).
[0057]
(Filtration speed changing step)
　As a result, the water quality evaluation value is equal to or greater than a predetermined threshold value, the operator performs a predetermined operation on the operation unit 27. Filtration rate adjustment section 28, based on the operation signal sent from the operating section 27, closes the on-off valve V11, V12, to open the on-off valve V13, V14.
　Then, as shown in FIG. 10, a portion of the sand filtration apparatus 21D of the filter subunit R2 downstream, sand filtration apparatus 21D of the filter group R1 of the upstream side, 21E, it is connected in parallel to 21F. Thus, intake seawater from intake tube P1 is the upstream side of the filter group R1 of the sand filtration apparatus 21D, 21E, and 21F, a sand filtration device 21D on the downstream side of the filter group R2, the branched and parallel to It flows. Sand filtration apparatus 21D of the filter group R1 of the upstream side, 21E, 21F and the downstream filtered water filtered by the sand filter apparatus 21D of the filter subunit R2 is sand filtration device downstream of the filter group R2 21E, It is further filtered through 21F.
[0058]
　In this way, in the filtration apparatus group R1 of the first stage is the upstream side, to increase the number of sand filtration device 21 seawater is passed through, one by one sand filter filtration apparatus group R1 in the first stage filtration rate in the apparatus 21 is lowered (step S3).
[0059]
　With this configuration, while increasing the number of the sand filtration apparatus 21 for passing water to seawater, decreasing the filtration rate of every single sand filtration apparatus 21, the volume of treated water in the entire pre-processing unit 20 it can be suppressed to reduce.
　For example, in the state in FIG. 9, the sand filtration apparatus 21D of the filter group R1 in the first stage, 21E, lowering the filtration rate to 50% at 21F, a two-stage filtration unit group R2 sand filtration apparatus 21D , 21E, filtered water to be filtered through 21F are it becomes water filtration of total of 150% min.
　In contrast, in the state of FIG. 10, the sand filtration apparatus 21D of the filter group R1 in the first stage, 21E, even when the filtration rate of 21F and second stage of the filtration unit group R2 is reduced to 50%, second stage the sand filtration apparatus 21E of the filter group R2, filtered water to be filtered through 21F can obtain water filtration of a total of 200% min.
　Thus, while suppressing a reduction in water filtration (process water), it is possible to suppress the fluctuation of the water quality after the filtration.
[0060]
　Again, after reducing the filtration rate from the reference speed, at a predetermined timing, sand filtration apparatus 21A, filtration treatment with 21B acquires the detection unit 25 to the water quality evaluation value of the sea water which has been subjected (step S4).
[0061]
　The operator checks the information based on the quality evaluation value to be displayed on the display unit 26 determines the acceptability of the quality of seawater filtering process is performed (step S5).
[0062]
(Filtration speed changing step)
　As a result, the water quality evaluation value is equal to or remains above a predetermined threshold value, the flow returns to step S4.
　On the other hand, the water quality evaluation value, a case in which it is in a lower value than the predetermined threshold value, with opening the on-off valve V11, V12, closing the on-off valve V13, V14, first-stage filtration unit group R1 that had decreased sand filtration apparatus 21D, 21E, returning the filtration rate of 21F and second stage of the filtration unit group R2 to the reference speed (step S6).
[0063]
　The pre-processing unit 20 of the second embodiment described above, a portion of the sand filtration apparatus 21D of the second stage of the filter group R2, sand filtration apparatus 21D that constitutes the filtering device group R1 in the first stage, 21E, is connected in parallel to 21F, a sand filtration device 21D of a two-stage filtration unit group R2, the first stage of the sand filtration apparatus 21D, 21E, by passed through the seawater parallel to and 21F, the first stage it is possible to increase the number of sand filtration device 21. Thus, with causes to increase the number of sand filtration device 21 seawater is passed through, seawater is a split into a plurality of sand filtration device 21 by passing water, filtered in one single sand filtration apparatus 21 can reduce the rate, while suppressing the reduction of the amount of water treated in the pretreatment unit 20, it is possible to suppress the fluctuation of the water quality after the filtration. Moreover, by using as part of the sand filtration apparatus 21 first stage of sand filtration device 21 of the plurality of sand filtration apparatus 21 on the downstream side, there is no need to provide a spare sand filtration apparatus 21 or the like.
[0064]
(Other Modifications)
　The present invention is not limited to the embodiments described above, without departing from the scope of the invention include those in which various modifications to the embodiments described above. That is, the specific shapes and configurations such as listed in embodiment merely examples and can be appropriately changed.
[0065]
　For example, the sand filtration system 21 has been exemplified as a filtering device, the specific configuration is not intended to be limiting in any way. Moreover, the filtration device other than sand filtration device 21 can also be used in filtration apparatus of the preprocessing unit.
[0066]
　Further, in the embodiments described above, the pre-processing unit 20 has been described as an example a case where a biofilm. However, the pre-processing unit 20 is not limited to the case where a biofilm. Furthermore, a case has been described which performs Mukusurichu pretreatment to an example, it may be a configuration for performing filtering in preprocessing desalting treatment may be pretreated non Mukusurichu pretreatment.
[0067]
　Further, parallel sand filtration apparatus 21, the number connected in series may be appropriately changed. That, or the number of connecting in parallel the sand filtration apparatus 21 into four or more, or the number or in series with three or more.
[0068]
　The desalination process unit 50, a seawater reverse osmosis membrane treatment apparatus 51, a configuration and a brackish water for reverse osmosis membrane treatment apparatus 52 is not limited thereto. Only seawater reverse osmosis membrane treatment apparatus 51 may be provided in desalination unit 50.
　Further, before the processing unit 20 in the upstream feeding the sea water, the inlet P2 connected to intake pipes P1, may be charged coagulant and a pH adjusting agent or the like.
[0069]
　Other than this, for example, in the above embodiment and its modifications, seawater is taken as an example water treatment system for desalination, also for other applications of the water treatment system, effectively the present invention it is possible to apply.
Industrial Applicability
[0070]
　This invention sea water can be applied to a water treatment system, such that processes desalination. According to the water treatment method and a water treatment system of the present invention, it is possible to suppress variation in filtration quality even when the quality fluctuation of the water to be treated has occurred.
DESCRIPTION OF SYMBOLS
[0071]
10 water treatment system
20 pre-processing unit (processing
unit) 21, 21A, 21B, 21C, 21D, 21E, 21F sand filtration device (filtration
device) 21f filter unit (filter material
layer) 25 detector
26 display unit
27 operating unit
28, 28B filtration rate adjustment section
30 the cartridge filter
40 the high-pressure pump
50 desalination unit
reverse for 51 seawater osmosis membrane treatment apparatus (reverse osmosis
unit) 52 brackish water for reverse osmosis membrane treatment apparatus (reverse osmosis
unit) 60 energy recovery device
61, 62 rotor
F reverse osmosis membrane
P1 intake pipe
P2 inlet
P3, P4, P5, P6, P7 connecting pipe
P8 drain pipe
P9 supply pipe
P10 is turned portion
P11 drainage pipe
P12 branch pipes
P21, P22, P23, P26 connecting pipe
P24, P25 parallel connection tube
R, R1, R2 filtration unit group
S1, S2, S3, S4, S5, S6 step
V1-off valve (first switching
unit) V11 ~ V14-off valve (second switching unit)

The scope of the claims
[Requested item 1]
And water quality acquisition step of acquiring quality evaluation value of the water to be treated to filtration treatment prior to the desalting process is performed,
　when the value of the acquired quality evaluation values becomes a predetermined threshold value or more, the object and filtration rate changing step of reducing the filtration rate of the treated water from the reference speed,
the water treatment method comprising.
[Requested item 2]
　The filtration rate changing step, said with increasing the number of filtering devices treatment water is passed through, the multiple of the filtering device by each passing water diverted water to be treated, one single water treatment method according to claim 1 to reduce the filtration rate in the filtration apparatus.
[Requested item 3]
　The filtration treatment is sequentially passing water the water to be treated a filtration device in a plurality of stages,
　the filtration rate changing step, from the filtration rate of the filter apparatus after the second stage of the filtration rate of the filtration device in the first stage water treatment method according to claim 2, also reduces.
[Requested item 4]
　At least a portion of said filter device subsequent second stage plurality arranged in parallel,
　the filtration rate changing step, among the plurality of the filtering devices are arranged in parallel after the second stage, a portion of the filtering device When, by each passing water divert the water to be treated and the filtering apparatus of the first stage, according to claim 3 to reduce the filtration rate of the treated water that passed through the filtration apparatus of the first stage water treatment method.
[Requested item 5]
　Wherein in a state in which the filtration rate was reduced, the when the water quality evaluation value becomes a predetermined threshold value or more, water treatment according to any one of 4 claims 1 to return the filtration rate in the reference velocity Method.
[Requested item 6]
　A processing unit having a filtering device for performing filtering processing to the water to be treated passed through,
　a reverse osmosis unit for separating the treated water in which the filtration process is applied to the concentrated water and fresh water,
　and the processing unit a detector for detecting the water quality evaluation value of the water to be treated between the said reverse osmosis unit,
　a display unit for displaying information based on the quality evaluation value,
　and an operator operable operation unit,
　wherein based on the operation signal sent by the operation of the operation unit is performed in accordance with the information displayed on the display unit, and a filtration rate adjusting unit that reduces the filtration rate of the water to be treated in said filtration system
comprises water treatment system.
[Requested item 7]
　A processing unit having a filtering device for performing filtering processing to the water to be treated passed through,
　a reverse osmosis unit for separating the treated water in which the filtration process is applied to the concentrated water and fresh water,
　and the processing unit a detector for detecting the water quality evaluation value of the water to be treated between the said reverse osmosis membrane apparatus,
　when the value of the quality evaluation value becomes a predetermined threshold value or more, the water to be treated in said filtration apparatus a filtration rate adjusting unit that reduces the filtration rate of the
　water treatment system comprising a.
[Requested item 8]
　Wherein the processing unit,
　a filtration unit group including a plurality of filtration devices arranged in parallel with each other,
　has a first switching unit for switching the water flow and non-water flow into the filtering device, a
　said filtration rate adjustment section the water treatment system according to claim 6 or 7 reduces the filtration rate by increasing the number of filtering devices the water to be treated in the filtration device group is passed through by switching the first switching unit .
[Requested item 9]
　Wherein the processing unit, which has a filtration device group including a plurality of filtration devices arranged in parallel with one another, the filtration unit group is provided in a plurality of stages in series with one another,
　wherein the processing unit, the subsequent second stage having a second switching unit that switches as part of the filtration device of the filtering unit group are connected in parallel to the filtration device of the filtering unit group in the first stage,
　the filtration rate adjusting unit, the second switching unit by switching, by increasing the number of the filtering device of the filtering unit group in the first stage, any one of claims 6 8 for reducing the filtration rate in the filtration apparatus of the filtration unit group in the first stage one the water treatment system according to claim.