JP2011083666A - Water treatment system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water treatment system which can reduce the amount of injected fouling inhibitor to zero or can greatly reduce the amount thereof and inhibit generation of fouling on a reverse osmosis membrane. <P>SOLUTION: The water treatment system 1 includes pretreatment devices 4, 5, 6, 7 for removing impurities contained in raw water W1 to produce water to be treated W1a, and a reverse osmosis membrane device 8 for performing membrane separation of the water to be treated W1a into a permeate W2 and a concentrate W3 using a reverse osmosis membrane. The reverse osmosis membrane is a low fouling membrane having a permeation flux of 1.17×10<SP>-5</SP>m<SP>3</SP>/m<SP>2</SP>/MPa/s or more and having a salt rejection rate of 99% or more when evaluated in a non-fouling state using an aqueous solution having a sodium chloride concentration of 1,500 mg/L under conditions where an operating pressure is 1 MPa, a recovery rate is 15%, temperature is 25°C, and pH is 7. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a water treatment system that performs various types of water treatment on raw water.

  Conventionally, after the raw water containing organic components is purified by biological treatment, the permeated water can be used as drinking water or industrial water by performing a membrane separation process that separates the permeated water and concentrated water by a reverse osmosis membrane. A technique for reproducing data up to a level is provided (see, for example, Patent Document 1).

  In a water treatment system using a reverse osmosis membrane, fouling occurs, which is an impediment to maintaining the permeation flux and stabilizing the quality of treated water. “Fouling” refers to a phenomenon in which suspended substances, sparingly soluble salts, etc. in raw water are deposited or adsorbed on the membrane surface of a reverse osmosis membrane, causing a decrease in permeation flux and salt removal rate.

  According to the technique described in Patent Document 1, based on the organic matter concentration in the raw water upstream of the reverse osmosis membrane, by injecting into the raw water an agent that suppresses the occurrence of fouling (hereinafter referred to as a fouling inhibitor). , Suppresses the occurrence of fouling.

JP 2007-229623 A

  However, according to the technique described in Patent Document 1, the cost required for water treatment (fresh water cost) increases due to the injection of the fouling inhibitor. Further, since the concentrated water is contaminated by the injection of the fouling inhibitor, draining the concentrated water out of the system may cause an environmental burden. Furthermore, if the injection of the fouling inhibitor is not properly maintained, frequent membrane cleaning is required, making continuous water treatment difficult.

  Therefore, the present invention provides a water treatment system that can reduce or greatly reduce the injection amount of a fouling inhibitor and can suppress the occurrence of fouling in a reverse osmosis membrane. Objective.

The present invention relates to a pretreatment device for producing treated water by removing impurities contained in raw water in advance, and a reverse osmosis membrane for performing a membrane separation process for separating the treated water into permeated water and concentrated water using a reverse osmosis membrane. The reverse osmosis membrane uses an aqueous solution having a sodium chloride concentration of 1500 mg / L as the water to be treated, in an unfouled state, with an operating pressure of 1 MPa, a recovery rate of 15%, and a temperature of 25. Water, which is a low fouling membrane having a permeation flux of 1.17 × 10 ⁻⁵ m ³ / m ² / MPa / s or higher and a salt removal rate of 99% or higher when evaluated under the conditions of ° C. and pH 7 It relates to a processing system.

Further, the reverse osmosis membrane is a permeation when evaluated in the fouling state using an aqueous solution having a sodium chloride concentration of 1500 mg / L as water to be treated and operating pressure of 1 MPa, recovery rate of 15%, temperature of 25 ° C. and pH of 7. A synthetic polyamide membrane having a flux of 8.2 × 10 ⁻⁶ m ³ / m ² / MPa / s or more and a salt removal rate of 99% or more is preferable.

  In addition, the pretreatment device is a biological treatment device that decomposes and removes organic components contained in raw water by microorganisms; a coagulation sedimentation treatment device that removes suspended substances contained in raw water by flocking with a flocculant; Processing equipment that captures and removes suspended solids by filtration media; activated carbon processing equipment that adsorbs and removes organic components and oxidizing substances contained in raw water using activated carbon; oxidizes dissolved iron and dissolved manganese contained in raw water Iron removal and manganese removal equipment insolubilized and removed by an agent; accelerated oxidation treatment equipment that decomposes and removes organic components contained in raw water by UV irradiation in the presence of an oxidizing agent; and hardness components contained in raw water It is preferable that any one or more of the water softening treatment devices that are adsorbed and removed by the exchange resin is used.

  Moreover, it is preferable to further comprise an electrodeionization apparatus that performs a membrane separation process for separating permeated water into deionized water and concentrated water by an ion exchange membrane on the downstream side of the reverse osmosis membrane apparatus.

  ADVANTAGE OF THE INVENTION According to this invention, while providing the injection amount of a fouling inhibitor to zero or reducing it significantly, providing the water treatment system which can suppress generation | occurrence | production of the fouling in a reverse osmosis membrane. it can.

It is a lineblock diagram showing water treatment system 1 of a 1st embodiment of the present invention. It is a block diagram which shows the water treatment system 1B of 2nd Embodiment of this invention. It is a block diagram which shows 1C of water treatment systems of 3rd Embodiment of this invention. It is a block diagram which shows 1D of water treatment systems of 4th Embodiment of this invention.

[First Embodiment]
Below, the water treatment system 1 of 1st Embodiment of this invention is demonstrated, referring FIG. Drawing 1 is a lineblock diagram showing water treatment system 1 of a 1st embodiment of the present invention.
The water treatment system 1 of 1st Embodiment shown in FIG. 1 removes an impurity from the waste_water | drain (raw water W1) containing the organic component discharged | emitted at a factory etc., for example, can be reused as industrial water etc. Water for demineralized water (treated water W2) is produced.

As shown in FIG. 1, a water treatment system 1 includes a raw water tank 2, a raw water pump 3, an activated sludge treatment device 4 (a kind of biological treatment device) that is a pretreatment device, and a sand filtration device that is a pretreatment device. 5 (a kind of filtration treatment device), activated carbon adsorption device 6 (a kind of activated carbon treatment device) as a pretreatment device, accelerated oxidation treatment device 7 as a pretreatment device, and raw water W1 (treated) through the pretreatment device A reverse osmosis membrane device 8 for performing a membrane separation treatment of water W1a), a treated water tank 9, a water flow line L1, L2, L3, L4, L5, L6, L7, a concentrated water line L8, and a drainage line L9 The concentrated water reflux line L10 and the valves 10 and 11 are mainly configured.
In addition, the “line” in this specification is a general term for a line capable of flowing a fluid such as a flow path, a path, and a pipeline.

  According to this water treatment system 1, the raw water W 1 that has passed through the raw water tank 2 is sequentially sent to the activated sludge treatment device 4, the sand filtration device 5, the activated carbon adsorption device 6, and the accelerated oxidation treatment device 7 by the raw water pump 3. It is purified and becomes treated water W1a. The treated water W1a becomes water (hereinafter referred to as “permeated water”) W2 finally purified by the reverse osmosis membrane device 8. The permeated water W2 is stored in the treated water tank 9.

Since the water treatment by the reverse osmosis membrane device 8 is the final treatment by the water treatment system 1 of the present embodiment, this permeated water is also referred to as “treated water”.
A part of water (hereinafter referred to as “concentrated water”) W3 concentrated by the reverse osmosis membrane device 8 is returned to the upstream side of the reverse osmosis membrane device 8 via the concentrated water reflux line L10.
Hereinafter, each part of the water treatment system 1 will be described in detail.

  The water flow line L1 introduces the raw water W1 into the raw water tank 2. The raw water tank 2 is connected to the downstream end of the water flow line L1. The raw water tank 2 stores the raw water W1 passed through the water passage line L1. An activated sludge treatment device 4 is provided on the downstream side of the raw water tank 2. The raw water tank 2 and the activated sludge treatment device 4 are connected by a water passage line L2 through which water can flow.

  The raw water pump 3 is provided in this water flow line L2. The raw water pump 3 sends the raw water W1 stored in the raw water tank 2 toward the activated sludge treatment device 4. Operation (drive and stop) of the raw water pump 3 is controlled by a control device (not shown).

The activated sludge treatment apparatus 4 decomposes and removes organic components contained in the raw water W1 by microorganisms. The activated sludge treatment apparatus 4 is connected to the downstream end of the water flow line L2.
The activated sludge treatment apparatus 4 includes, for example, an aeration tank and a sedimentation tank connected to the aeration tank. The aeration tank stores the raw water W1 and decomposes organic components contained in the raw water W1 with microorganisms using activated sludge. The sedimentation tank settles and separates activated sludge and stores the separated supernatant. The activated sludge mixed liquid separated in the settling tank is configured to be returned to the aeration tank.
On the downstream side of the activated sludge treatment apparatus 4, a water passage line L <b> 3 that allows passage of the supernatant liquid of the sedimentation tank is connected. The downstream end of the water flow line L3 is connected to the sand filtration device 5.

The sand filtration device 5 performs a filtration process for trapping and removing suspended substances contained in the raw water W1 with a filtration medium. The sand filtration device 5 is connected to the downstream end of the water flow line L3. Examples of the sand filtration device 5 include a tower type having a filtration medium layer (not shown) formed of a coarse filter medium such as meteorite and a fine filter medium such as anthracite and filter sand. The sand filtration device 5 is configured to be backwashable, and the suspended substance trapped in the filtration medium layer is periodically discharged.
On the downstream side of the sand filtration device 5, a water passage line L <b> 4 is connected through which the filtrate produced by the sand filtration device 5 can flow. The downstream end of the water flow line L4 is connected to the activated carbon adsorption device 6.

The activated carbon adsorbing device 6 adsorbs and removes organic components and oxidizing substances contained in the raw water W1 with activated carbon. The activated carbon adsorption device 6 is connected to the downstream end of the water flow line L4. Examples of the activated carbon adsorbing device 6 include a tower type having a packed bed of granular activated carbon and a built-in cartridge filled with fibrous activated carbon.
On the downstream side of the activated carbon adsorption device 6, a water passage line L <b> 5 capable of passing water is connected. The downstream end of the water flow line L5 is connected to the accelerated oxidation treatment device 7.

The accelerated oxidation treatment device 7 decomposes and removes organic components contained in the raw water W1 by ultraviolet irradiation in the presence of an oxidizing agent. The accelerated oxidation treatment device 7 is connected to the downstream end of the water flow line L5.
The accelerated oxidation treatment device 7 includes an oxidant addition device (not shown) that adds a predetermined oxidant to the raw water W1, an ultraviolet lamp (not shown) that irradiates the raw water W1 with ultraviolet rays, and a treatment in which the raw water W1 circulates. A tank (not shown).

  The oxidizing agent adding device is configured to add a predetermined oxidizing agent (for example, sodium hypochlorite) to the raw water W1. The ultraviolet lamp is configured to irradiate the raw water W1 with ultraviolet rays having a predetermined wavelength. The treatment tank is configured in a shape (for example, a cylindrical shape) through which the raw water W1 can flow. The ultraviolet lamp is accommodated in the processing tank.

  The raw water W1 in the treatment tank contains an oxidant added by an oxidant addition device. When this oxidizing agent is irradiated with ultraviolet rays by an ultraviolet lamp, accelerated oxidation treatment is performed. “Accelerated oxidation treatment” refers to the generation of hydroxyl radicals having a strong oxidizing power by irradiating a specific oxidant with ultraviolet rays, thereby oxidatively decomposing a hardly decomposable substance contained in the raw water W1 and This refers to a treatment that decomposes the chromaticity component and odor component of W1 to sterilize microorganisms.

  The accelerated oxidation treatment device 7 irradiates the raw water W1 with ultraviolet rays by an ultraviolet lamp while circulating the raw water W1 in the treatment tank in the presence of the oxidizing agent. Thereby, the accelerated oxidation treatment apparatus 7 can generate hydroxyl radicals in the raw water W1. Therefore, the accelerated oxidation treatment apparatus 7 oxidizes and decomposes the hardly decomposable substance contained in the raw water W1. Further, the accelerated oxidation treatment device 7 decomposes chromaticity components and odor components in the raw water W1. Furthermore, the accelerated oxidation treatment apparatus 7 can also sterilize microorganisms.

  As described above, various impurities contained in the raw water W1 are removed in advance (pretreatment) by the pretreatment device including the activated sludge treatment device 4, the sand filtration device 5, the activated carbon adsorption device 6, and the accelerated oxidation treatment device 7, The treated water W1a is manufactured. In addition, the reverse osmosis membrane mentioned later may deteriorate with the oxidizing agent which remains in the to-be-processed water W1a. Therefore, it is desirable to further provide an activated carbon adsorbing device after the accelerated oxidation treatment device 7 so that the residual amount of the oxidizing agent in the water to be treated W1a is substantially zero.

  A water passage line L <b> 6 capable of passing water is connected to the downstream side of the accelerated oxidation treatment device 7. The downstream end of the water flow line L6 is connected to the reverse osmosis membrane device 8.

The reverse osmosis membrane device 8 uses a reverse osmosis membrane (hereinafter, also referred to as “RO membrane”) to treat water W1a produced by pretreatment by the accelerated oxidation treatment device 7 or the like with higher purity permeated water (treated water). ) A membrane separation process is performed on W2 and concentrated water W3 containing a large amount of impurities.
The reverse osmosis membrane device 8 is connected to the downstream side of the accelerated oxidation treatment device 7 through a water passage line L6.

  The reverse osmosis membrane device 8 includes a pressurizing pump 8a provided on the upstream side and an RO membrane module 8b provided on the downstream side. The pressurizing pump 8a pressurizes the water to be treated W1a supplied from the accelerated oxidation treatment apparatus 7 and sends it to the RO membrane module 8b. The RO membrane module 8b includes a single or a plurality of RO membrane elements (not shown), and the RO water W1a is subjected to membrane separation treatment with these RO membrane elements to produce the permeated water W2 and the concentrated water W3. . The RO membrane is a membrane capable of filtering a molecular weight of about several tens, and is configured as a low fouling membrane.

Hereinafter, the RO membrane used in the present embodiment will be described in detail. For example, the RO membrane uses an aqueous solution with a sodium chloride concentration of 1500 mg / L as the water to be treated in an unfouled state, and the permeation flow when evaluated under the conditions of operating pressure 1 MPa, recovery rate 15%, temperature 25 ° C. and pH 7. The low fouling film has a bundle of 1.17 × 10 ⁻⁵ m ³ / m ² / MPa / s or more and a salt removal rate of 99% or more.

The non-fouling state of the RO membrane means a state of a new membrane purchased from a membrane manufacturer, or a state in which the new membrane is preliminarily washed with clean water such as tap water or demineralized water. The operating pressure is an average operating pressure defined by JIS K3802-1995 “Membrane Terminology”, and indicates an average value of the primary inlet pressure and the primary outlet pressure of the RO membrane module 8b. The permeation flux is a value obtained by dividing the permeated water amount [m ³ / s] by the membrane area [m ² ] and the effective pressure [MPa]. The effective pressure is defined by JIS K3802-1995 “Membrane Term” and is a pressure obtained by subtracting the osmotic pressure difference and the secondary pressure from the operating pressure (average operating pressure).

Further, the RO membrane is a permeation flux when an aqueous solution having a sodium chloride concentration of 1500 mg / L is used as water to be treated in a fouling state, and is evaluated under the conditions of an operation pressure of 1 MPa, a recovery rate of 15%, a temperature of 25 ° C. and a pH of 7. Is preferably a synthetic polyamide film having a salt removal rate of 99% or more and 8.2 × 10 ⁻⁶ m ³ / m ² / MPa / s or more.

The fouling state of the RO membrane is the difference in membrane pressure when operated with a constant amount of permeate, using a non-ionic surfactant added to an aqueous solution with a sodium chloride concentration of 1500 mg / L as the water to be treated. This refers to a state in which the pressure has increased from 65% to 70% with respect to the membrane differential pressure at the start of operation.
As the nonionic surfactant, for example, polyoxyethylene octylphenyl ether is used. Further, the concentration of the nonionic surfactant is adjusted in the range where the fouling index (FI) value of the water to be treated is 0.3 to 0.5.

  The reverse osmosis membrane device 8 having such an RO membrane produces the permeated water (treated water) W2 while supplying the treated water W1a to the RO membrane, and the concentrated water in which the impurity concentration of the treated water W1a is increased. W3 is generated. The reverse osmosis membrane device 8 is connected with a water passage line L7 through which the permeated water W2 can pass and a concentrated water line L8 through which the concentrated water W3 can pass. The downstream end of the water flow line L7 is connected to the treated water tank 9. The water flow line L <b> 7 supplies the permeated water W <b> 2 manufactured by the reverse osmosis membrane device 8 to the treated water tank 9.

The treated water tank 9 stores the permeated water produced by the reverse osmosis membrane device 8 as treated water W2. The treated water tank 9 is connected to the downstream side of the reverse osmosis membrane device 8 through a water passage line L7.
The treated water tank 9 is connected to a supply facility such as industrial water in a factory via a water line (not shown). The treated water W2 stored in the treated water tank 9 is reused as various process water (for example, cleaning water and cooling water), middle water, miscellaneous water, and the like.

  The concentrated water line L8 is connected to the RO membrane module 8b and guides the concentrated water W3 from the RO membrane module 8b to the outside of the reverse osmosis membrane device 8. A branch portion J1 is provided at the downstream end of the concentrated water line L8. In this branch part J1, the drainage line L9 and the concentrated water recirculation line L10 are branched.

  The drainage line L9 branches from the concentrated water line L8 at the branch portion J1, and drains part of the concentrated water W3 from the RO membrane module 8b to the outside of the water treatment system 1. A valve 10 is provided in the drain line L9. The valve 10 can open and close the drain line L9.

  The concentrated water reflux line L10 branches from the concentrated water line L8 at the branch portion J1, and returns the remaining portion of the concentrated water W3 from the RO membrane module 8b to the water flow line L6 on the upstream side of the reverse osmosis membrane device 8. A valve 11 is provided in the concentrated water reflux line L10. The valve 11 can open and close the concentrated water reflux line L10. That is, the reverse osmosis membrane device 8 is configured to be capable of membrane separation processing by crossflow.

  In addition, although illustration is abbreviate | omitted, the pump which sends raw | natural water W1, the to-be-processed water W1a, the treated water W2, the concentrated water W3, etc. to the water flow line L1, L2, L3, L4, L5, L6, L7 etc. mentioned above. In addition, a valve for opening and closing the flow path is provided as appropriate. These pumps and valves are also controlled by a control device (not shown).

  Next, operation | movement of the water treatment system 1 of 1st Embodiment is demonstrated, referring FIG. The water treatment system 1 is operated and the raw water pump 3 is activated. Then, the raw water W1 (raw water) is passed from the raw water tank 2 to the activated sludge treatment device 4 through the water passage line L2. This raw water W1 contains suspended substances such as dust and colloidal particles.

  The organic components contained in the raw water W1 are decomposed and removed by microorganisms in the aeration tank of the activated sludge treatment apparatus 4. The raw water W1 from which the organic components have been removed is passed from the settling tank of the activated sludge treatment device 4 to the sand filtration device 5 via the water flow line L3.

The raw water W1 passed through the sand filtering device 5 is filtered by the filter medium layer of the sand filtering device 5 so that the dust, aggregates, and the like are captured and removed.
The raw water W1 that has passed through the sand filtering device 5 is passed through the activated carbon adsorbing device 6 through the water passing line L4. Organic components (organic components that cannot be completely removed by the activated sludge treatment device 4) and oxidizing substances contained in the raw water W1 are adsorbed and removed by the activated carbon of the activated carbon adsorption device 6.

  The raw water W1 that has passed through the activated carbon adsorption device 6 is passed through the treatment tank of the accelerated oxidation treatment device 7 through the water flow line L5. In the treatment tank of the accelerated oxidation treatment device 7, an oxidant (for example, sodium hypochlorite) is added by an oxidant addition device (not shown).

  The raw water W1 passed through the treatment tank is irradiated with ultraviolet rays by an ultraviolet lamp. When the raw water W1 containing the oxidizing agent is irradiated with ultraviolet rays, hydroxyl radicals are generated. The hydroxyl radical has a strong oxidizing power, and the accelerated oxidation treatment of the raw water W1 is performed in the treatment tank. Therefore, by this accelerated oxidation treatment, the hardly decomposable substance contained in the raw water W1 is oxidatively decomposed. Moreover, the chromaticity component and odor component contained in the raw water W1 are decomposed by this accelerated oxidation treatment. Furthermore, microorganisms contained in the raw water W1 are sterilized by this accelerated oxidation treatment.

  In addition, by performing the accelerated oxidation treatment of the raw water W1 by the accelerated oxidation treatment device 7 in this way, microorganisms grow and adhere to the RO membrane in the RO membrane of the downstream reverse osmosis membrane device 8, so-called biofouling. Occurrence can be suppressed.

  As described above, the raw water W1 is pretreated by passing through the activated sludge treatment device 4, the sand filtration device 5, the activated carbon adsorption device 6, and the accelerated oxidation treatment device 7. Thereby, impurities are purified and treated water W1a is manufactured.

The treated water W1a that has passed through the accelerated oxidation treatment device 7 is passed through the reverse osmosis membrane device 8 through the water passage line L6 and further purified. The treated water W1a is subjected to membrane separation treatment into permeated water W2 and concentrated water W3 by the RO membrane of the reverse osmosis membrane device 8. Thereby, the permeated water (treated water) W2 from which impurities such as dissolved salts have been removed can be obtained.
Since the RO membrane is configured as the low fouling membrane, the injection amount of the fouling inhibitor can be reduced to zero or greatly reduced, and the occurrence of fouling in the RO membrane can be suppressed. .

  The permeated water (treated water) W2 produced by the reverse osmosis membrane device 8 is passed through the treated water tank 9 via the water flow line L7 and stored in the treated water tank 9. The treated water W2 stored in the treated water tank 9 is reused as various process water, intermediate water, miscellaneous water, and the like.

  On the other hand, the concentrated water W3 generated in the reverse osmosis membrane device 8 is opened upstream of the reverse osmosis membrane device 8 via the concentrated water line L8, the branch portion J1, and the concentrated water reflux line L10 by opening and closing valves 10 and 11 as appropriate. Refluxed to the side. Further, a part of the concentrated water W3 generated in the reverse osmosis membrane device 8 can be connected to the system of the water treatment system 1 via the concentrated water line L8, the branch portion J1, and the drainage line L9 by opening and closing the valves 10 and 11 as appropriate. Drained outside.

As mentioned above, according to the water treatment system 1 of 1st Embodiment, each effect shown below is show | played. The water treatment system 1 according to the first embodiment includes a pretreatment device (an activated sludge treatment device 4, a sand filtration device 5, an activated carbon adsorption device 6 and an accelerated oxidation treatment device 7), and a permeated water W2 by treating the treated water W1a with an RO membrane. And a reverse osmosis membrane device 8 for performing a membrane separation process for separating the water into concentrated water W3. In addition, the RO membrane is a permeate flow in an unfouled state when an aqueous solution having a sodium chloride concentration of 1500 mg / L is used as water to be treated and evaluated under the conditions of an operating pressure of 1 MPa, a recovery rate of 15%, a temperature of 25 ° C., and a pH of 7. The low fouling film has a bundle of 1.17 × 10 ⁻⁵ m ³ / m ² / MPa / s or more and a salt removal rate of 99% or more. Therefore, generation of fouling in the RO membrane can be suppressed without injecting a fouling inhibitor.

  Therefore, the injection of the fouling inhibitor is unnecessary, and the cost for producing the permeated water W2 (fresh water cost) can be reduced. In addition, since the injection of the fouling inhibitor becomes unnecessary and the chemical contamination of the concentrated water W3 can be avoided, even if the concentrated water W3 is drained outside the water treatment system 1, it does not adversely affect the environment. That's it. Furthermore, chemical contamination of the permeated water W2 can be avoided. Moreover, since the cleaning frequency of the RO membrane can be reduced, continuous water treatment can be performed.

Further, the RO membrane is a permeation flux when an aqueous solution having a sodium chloride concentration of 1500 mg / L is used as water to be treated in a fouling state, and is evaluated under the conditions of an operation pressure of 1 MPa, a recovery rate of 15%, a temperature of 25 ° C. and a pH of 7. Is a synthetic polyamide film having a salt removal rate of 99% or more and 8.2 × 10 ⁻⁶ m ³ / m ² / MPa / s or more. Therefore, it is possible to suppress the occurrence of fouling in the RO membrane without injecting the inhibitor, and it is possible to ensure a predetermined permeation flux even in the fouling state. Therefore, since the cleaning frequency of the RO membrane can be reduced, continuous water treatment can be performed.

  Next, another embodiment of the present invention will be described. The other embodiments will be described mainly with respect to differences from the first embodiment, and the same configurations as those of the first embodiment will be denoted by the same reference numerals and detailed description thereof will be omitted. For the points not specifically described in other embodiments, the description of the first embodiment is appropriately applied or incorporated.

[Second Embodiment]
Next, a water treatment system 1B according to a second embodiment of the present invention will be described with reference to FIG. FIG. 2 is a configuration diagram showing a water treatment system 1B according to the second embodiment of the present invention. The water treatment system 1B according to the second embodiment removes impurities from waste water (raw water W1) containing organic components discharged from factories and the like, and desalinates the water to treat it as industrial water or the like (treated water). W2) is manufactured.

  As shown in FIG. 2, the water treatment system 1B of the second embodiment includes a raw water tank 2, a raw water pump 3, a membrane separation activated sludge treatment device 16 (a kind of biological treatment device) that is a pretreatment device, and activated carbon. Adsorption device 6, accelerated oxidation treatment device 7, reverse osmosis membrane device 8, treated water tank 9, water flow lines L1, L2, L5, L6, L7, L11, concentrated water line L8, and drainage line L9 The concentrated water reflux line L10 and the valves 10 and 11 are mainly configured. That is, the water treatment system 1B of the second embodiment is different in that it includes a membrane separation activated sludge treatment device 16 instead of the activated sludge treatment device 4 and the sand filtration device 5 of the water treatment system 1 of the first embodiment.

  The membrane separation activated sludge treatment apparatus 16 decomposes the organic components contained in the raw water W1 with microorganisms and separates the microorganisms and the filtrate (treated water) using a filtration membrane. The membrane separation activated sludge treatment device 16 is connected to the downstream end of the water flow line L2. The membrane separation activated sludge treatment apparatus 16 includes, for example, an aeration tank and a membrane separation tank having a filtration membrane. The aeration tank uses activated sludge to decompose organic components contained in the raw water W1 with microorganisms. The membrane separation tank produces a filtrate by subjecting a liquid (supernatant liquid) obtained by sedimentation of activated sludge to membrane separation.

A filtration membrane is immersed in the membrane separation tank. As this filtration membrane, for example, an ultrafiltration (UF) membrane or a microfiltration (MF) membrane can be used. The activated sludge mixed liquid concentrated in the membrane separation tank is configured to be returned to the aeration tank.
On the downstream side of the membrane separation activated sludge treatment device 16, a water passage line L11 through which the filtrate can be passed is connected. The downstream end of the water flow line L11 is connected to the activated carbon adsorption device 6. Since the configuration on the downstream side from the activated carbon adsorption device 6 is the same as in the case of the first embodiment, a duplicate description is omitted.

  Next, operation | movement of the water treatment system 1B of 2nd Embodiment is demonstrated, referring FIG. The water treatment system 1B is operated and the raw water pump 3 is activated. Then, the raw water W1 (raw water) is passed from the raw water tank 2 to the membrane separation activated sludge treatment device 16 through the water passage line L2.

  The organic components contained in the raw water W1 are decomposed and removed by microorganisms in the aeration tank of the membrane separation activated sludge treatment apparatus 16. The raw water W1 from which the organic components have been removed is filtered in the membrane separation tank of the membrane separation activated sludge treatment device 16, and is passed through the activated carbon adsorbing device 6 through the water passage line L11.

  Since the pretreatment process in the activated carbon adsorption device 6 and the accelerated oxidation treatment apparatus 7 and the treatment process in the reverse osmosis membrane apparatus 8 are the same as those in the first embodiment, a duplicate description is omitted.

As mentioned above, according to the water treatment system 1B of 2nd Embodiment, while having the same effect as the water treatment system 1 of the said 1st Embodiment, each effect shown below is show | played.
The water treatment system 1B of the second embodiment includes a membrane separation activated sludge treatment device 16, an activated carbon adsorption device 6, and an accelerated oxidation treatment device 7 as pretreatment devices. Therefore, even in the case of such a pretreatment device, injection of a fouling inhibitor can be made unnecessary, and occurrence of fouling in the RO membrane can be suppressed.

[Third Embodiment]
Next, a water treatment system 1C according to a third embodiment of the present invention will be described with reference to FIG. FIG. 3 is a configuration diagram showing a water treatment system 1C according to a third embodiment of the present invention. The water treatment system 1C of the third embodiment removes impurities from wastewater (raw water W1) containing inorganic components discharged from factories and the like, and desalinates the water to treat it as industrial water or the like (treated water). W2) is manufactured.

  As shown in FIG. 3, the water treatment system 1 </ b> C of the third embodiment includes a raw water tank 2, a raw water pump 3, a coagulation sedimentation treatment device 19 that is a pretreatment device, a sand filtration device 5, and an accelerated oxidation treatment device. 7, reverse osmosis membrane device 8, treated water tank 9, water flow lines L1, L2, L6, L7, L12, L13, concentrated water line L8, drainage line L9, concentrated water reflux line L10, The valves 10 and 11 are mainly configured. That is, 1 C of water treatment systems of 3rd Embodiment differ in the point provided with the coagulation sedimentation processing apparatus 19 instead of the activated sludge processing apparatus 4 and the activated carbon adsorption apparatus 6 of the water treatment system 1 of 1st Embodiment.

  The coagulation sedimentation processing device 19 is a device that combines suspended substances contained in the raw water W1 with each other by a coagulant to generate (flocculate) and remove large particles. The coagulation sedimentation treatment device 19 includes a coagulant adding unit (not shown) for adding a coagulant to the raw water W1, a stirring unit (not shown) for stirring the raw water W1 to which the coagulant is added, and the raw water W1. And a precipitation part (not shown) for flocking and suspending the suspended substance.

  The flocculant is to neutralize the charge of the suspended matter (fine particles) in the raw water W1 to form an aggregate. The suspended substance having a size of about several μm passes through the filter medium layer (not shown) of the sand filter device 5 as it is. Therefore, the suspended substance is flocked by adding a flocculant to the raw water W1, and the sand filtration device 5 can be easily filtered. As the flocculant, for example, an inorganic flocculant can be used, and specific examples include polyaluminum chloride (PAC) and aluminum sulfate.

The flocculant addition part is comprised from the flocculant storage part which stores a flocculant, and the flocculant addition pump which adds the flocculant of the flocculant storage part to raw | natural water W1. The stirring unit is configured as a stirrer that is rotated by a motor or the like. The sedimentation part is comprised as a container which stores the suspended substance made into the flock.
The flocculant addition unit and the stirring unit of the coagulation sedimentation processing device 19 are configured to be controllable by a control device (not shown).

  On the downstream side of the coagulation sedimentation treatment device 19, a water flow line L12 through which the raw water W1 subjected to the coagulation sedimentation treatment can be passed is connected. The downstream end of the water flow line L12 is connected to the sand filtration device 5.

  In addition, a water passage line L <b> 13 through which the raw water W <b> 1 filtered by the sand filtration device 5 can be passed is connected to the downstream side of the sand filtration device 5. The downstream end of the water flow line L13 is connected to the accelerated oxidation treatment device 7. Since the configuration on the downstream side from the accelerating oxidation treatment apparatus 7 is the same as that in the first embodiment, a duplicate description is omitted.

  Next, the operation of the water treatment system 1C of the third embodiment will be described with reference to FIG. The water treatment system 1C is operated and the raw water pump 3 is activated. Then, the raw water W1 (raw water) is passed from the waste water treatment tank 2 to the coagulation sedimentation treatment device 19 via the water flow line L2.

In the coagulation sedimentation processing apparatus 19, the raw water W1 is stirred by the stirring unit, and the coagulant is added to the raw water W1 by the coagulant adding unit. Suspended substances in the raw water W1 gradually become flocculated and settle in the sedimentation part. Thereby, suspended substances contained in the raw water W1 are removed, and the filtration process by the sand filtration device 5 is facilitated.
The raw water W1 from which the flocked suspended matter has been removed is passed from the sedimentation section to the sand filtration device 5 through the water passage line L12.

  Since the pretreatment process in the sand filtration device 5 and the accelerated oxidation treatment device 7 and the treatment step in the reverse osmosis membrane device 8 are the same as those in the first embodiment, a duplicate description is omitted.

As described above, according to the water treatment system 1C of the third embodiment, the same effects as the water treatment system 1 of the first embodiment are exhibited, and the following effects are exhibited.
The water treatment system 1C of the third embodiment includes a coagulation sedimentation treatment device 19, a sand filtration device 5, and an accelerated oxidation treatment device 7 as pretreatment devices. Therefore, even in the case of such a pretreatment device, injection of a fouling inhibitor can be made unnecessary, and occurrence of fouling in the RO membrane can be suppressed.

[Fourth Embodiment]
Next, a water treatment system 1D according to a fourth embodiment of the present invention will be described with reference to FIG. FIG. 4 is a configuration diagram showing a water treatment system 1D according to the fourth embodiment of the present invention. The water treatment system 1D according to the fourth embodiment removes impurities from the raw water W1 such as ground water and river water, and desalinates to produce deionized water (pure water) W4.

  As shown in FIG. 4, the water treatment system 1D of the fourth embodiment includes a raw water tank 2, a raw water pump 3, an iron removal manganese treatment device 21 that is a pretreatment device, and an activated carbon adsorption device that is a pretreatment device. 6 (a kind of activated carbon treatment device), a water softening treatment device 22 as a pretreatment device, a reverse osmosis membrane device 8, an electrodeionization device 23, a treated water tank 24, and water flow lines L1, L2, L7 , L14, L15, L16, L17, concentrated water line L8, drainage lines L9, L18, concentrated water reflux line L10, and valves 10, 11.

  The iron removal manganese removal treatment device 21 insolubilizes and removes dissolved iron and dissolved manganese contained in the raw water W1 with an oxidizing agent. Specifically, the iron removal manganese removal treatment device 21 is provided with an oxidant addition unit for adding an oxidant such as sodium hypochlorite to the raw water W1 and a granular anthracite layer on the manganese oxidation catalyst layer. And a filtration medium layer. That is, the dissolved iron in the raw water W1 is oxidized and precipitated by sodium hypochlorite added to the raw water W1 by the oxidant addition unit. Thereby, the dissolved iron in the raw water W1 is removed. Further, dissolved manganese in the raw water W1 is oxidized and removed by the manganese oxidation catalyst. The filtration medium layer of the iron removal and manganese removal treatment device 21 is configured to be backwashable in the same manner as the filtration medium layer of the sand filtration device 5 described above.

  On the downstream side of the iron removal manganese removal treatment device 21, a water passage line L14 through which the raw water W1 from which dissolved iron and dissolved manganese have been removed can be passed. The downstream end of the water flow line L14 is connected to the activated carbon adsorption device 6.

  Further, on the downstream side of the activated carbon adsorption device 6, a water passage line L15 through which the raw water W1 from which organic components and oxidizing substances have been removed can be passed is connected. The downstream end of the water flow line L15 is connected to the water softening device 22.

  The water softening treatment device 22 removes the hardness components (calcium ions and magnesium ions) contained in the raw water W1 by adsorption with a cation exchange resin (not shown). The water softening device 22 is mainly composed of a resin tube (not shown), a control valve (not shown), and a salt water supply device (not shown) for producing salt water and supplying it to the resin tube. .

  The resin cylinder accommodates a cation exchange resin (not shown). The resin cylinder is subjected to water softening treatment by replacing the hardness component contained in the raw water W1 with a monovalent cation (for example, sodium ion) with a cation exchange resin to produce soft water. The control valve switches between the water softening treatment and the regeneration treatment of the water softening treatment device 22. The control valve is configured to be controllable by a control device (not shown). The salt water supply device manufactures salt water for regenerating the cation exchange resin and supplies it to the resin cylinder.

A water passage line L <b> 16 through which soft water (treated water W <b> 1 a) can flow is connected to the downstream side of the water softening device 22. The downstream end of the water flow line L16 is connected to the reverse osmosis membrane device 8.
A water flow line L7 is connected to the downstream side of the reverse osmosis membrane device 8. The downstream end of the water flow line L7 is connected to the electrodeionization device 23.

  The electrodeionization device 23 performs a membrane separation process in which the permeated water W2 produced by the reverse osmosis membrane device 8 is separated into deionized water W4 and concentrated water W5 by an ion exchange membrane (not shown). Specifically, the electrodeionization apparatus 23 includes a demineralization chamber (not shown) and a concentration chamber (not shown). The desalting chamber (not shown) and the concentration chamber are formed by alternately arranging a cation exchange membrane (not shown) and an anion exchange membrane (not shown). An ion exchange resin is accommodated in the desalting chamber. The electrodeionization device 23 removes ions in the permeate W2 that could not be removed by the reverse osmosis membrane device 8 in the desalination chamber by passing a direct current through the desalination chamber and the concentration chamber. (Pure water) It is comprised so that W4 can be manufactured. Further, the electrodeionization device 23 is configured to generate concentrated water W5 in which the impurity concentration of the permeated water W2 is increased in the concentration chamber.

  On the downstream side of the electrodeionization device 23, a water passage line L17 through which deionized water W4 produced in the desalination chamber can be passed, and a drain line L18 through which the concentrated water W5 generated in the concentrating chamber can pass. Is connected. The downstream end of the water flow line L17 is connected to the treated water tank 24. The water flow line L <b> 17 supplies the deionized water W <b> 4 produced by the electrodeionization device 23 to the treated water tank 24.

The treated water tank 24 stores deionized water W4 produced by the electrodeionization device 23. The treated water tank 24 is connected to the downstream side of the demineralization chamber of the electrodeionization device 23 via a water passage line L17.
The treated water tank 24 is connected to, for example, a deionized water (pure water) supply facility in a factory via a water line (not shown).

  The drain line L18 is connected to the concentration chamber of the electrodeionization device 23, and drains the concentrated water W5 from the electrodeionization device 23 to the outside of the water treatment system 1. The drain line L18 is provided with a valve (not shown) for opening and closing the drain line L18. The concentrated water W5 is often better in quality than the water to be treated W1a. Therefore, the concentrated water W5 can be returned to the upstream side of the reverse osmosis membrane device 8.

  Next, the operation of the water treatment system 1D of the fourth embodiment will be described with reference to FIG. When the water treatment system 1D is operated, the raw water pump 3 is activated by a control device (not shown). Then, the raw water W1 (raw water) is passed from the raw water tank 2 to the iron removal and manganese removal treatment device 21 through the water passage line L2.

In the iron removal and manganese removal treatment apparatus 21, an oxidizing agent such as sodium hypochlorite is added to the raw water W1 by the oxidizing agent addition unit. The dissolved iron in the raw water W1 is oxidized and precipitated by sodium hypochlorite. Thereby, the dissolved iron in the raw water W1 is insolubilized and removed. Dissolved manganese in the raw water W1 is oxidized by the manganese oxidation catalyst, insolubilized and removed.
The raw water W1 from which dissolved iron and dissolved manganese have been removed is passed through the activated carbon adsorbing device 6 through the water passage line L14. Since the pretreatment process in the activated carbon adsorption device 6 is the same as in the case of the first embodiment, a duplicate description is omitted.

  The raw water W1 that has passed through the activated carbon adsorption device 6 is passed through the water softening device 22 through the water flow line L15. In the water softening device 22, hardness components (calcium ions and magnesium ions) contained in the raw water W1 are adsorbed and removed by a cation exchange resin (not shown), and soft water (treated water W1a) is produced. The soft water is passed through the reverse osmosis membrane device 8 through the water passage line L16. The soft water is subjected to membrane separation treatment into permeated water W2 and concentrated water W3 by the RO membrane of the reverse osmosis membrane device 8. Thereby, the permeated water W2 from which impurities such as dissolved salts have been removed can be obtained.

  The permeated water W2 produced by the reverse osmosis membrane device 8 is passed through the electrodeionization device 23 through the water passage line L7. In the electrodeionization apparatus 23, the permeated water W2 is separated into deionized water W4 and concentrated water W5 by an ion exchange membrane (not shown). That is, in the electrodeionization device 23, ions in the permeated water W2 that could not be removed by the reverse osmosis membrane device 8 are removed in the desalting chamber, and deionized water (pure water) W4 with high purity is produced. The deionized water W4 is supplied to the treated water tank 24 through the water passage line L17 and stored.

  The concentrated water W5 generated in the concentration chamber of the electrodeionization device 23 is drained out of the water treatment system 1 via the drainage line L18 or returned to the upstream side of the reverse osmosis membrane device 8.

As described above, according to the water treatment system 1D of the fourth embodiment, the following effects are exhibited.
Water treatment system 1D of 4th Embodiment is provided with the iron removal manganese removal processing apparatus 21, the activated carbon adsorption apparatus 6, and the water softening processing apparatus 22 as a pre-processing apparatus. Therefore, even in the case of such a pretreatment device, injection of a fouling inhibitor can be made unnecessary, and occurrence of fouling in the RO membrane can be suppressed.

  In addition, an electrodeionization device 23 is further provided on the downstream side of the reverse osmosis membrane device 8. Therefore, ions in the permeated water W2 that could not be removed by the reverse osmosis membrane device 8 can be removed, and deionized water (pure water) W4 with high purity can be produced.

As mentioned above, although one Embodiment of this invention was described, this invention is not restrict | limited to embodiment mentioned above, It can change suitably.
For example, in the first embodiment to the fourth embodiment, the preprocessing apparatus has been described as including the one shown in FIGS. 1 to 4, but is not limited thereto. The pretreatment device is an activated sludge treatment device 4 that is a biological treatment device, a membrane separation activated sludge treatment device 16 that is a biological treatment device, a coagulation sedimentation treatment device 19, a sand filtration device 5 that is a filtration treatment device, and an activated carbon treatment device. What is necessary is just to be comprised from any one or more among the activated carbon adsorption apparatus 6, the iron removal manganese removal processing apparatus 21, the accelerated oxidation processing apparatus 7, and the water softening processing apparatus 22. FIG.

  Moreover, in the said 1st Embodiment and the said 3rd Embodiment, although demonstrated as what has the sand filtration apparatus 5 as a filtration processing apparatus, it is not limited to this. For example, instead of the sand filtration device 5, a filtration processing device using a filtration medium such as an ultrafiltration (UF) membrane or a microfiltration (MF) membrane may be provided.

  Moreover, in the said 1st Embodiment, the said 2nd Embodiment, and the said 4th Embodiment, although the activated carbon adsorption | suction apparatus 6 was demonstrated as an apparatus aiming at the adsorption effect by activated carbon, it is not limited to this. For example, the activated carbon adsorbing device 6 may be a device that aims at a filtering action using activated carbon as a filtration medium together with an adsorbing action by activated carbon.

1, 1B, 1C, 1D Water treatment system 4 Activated sludge treatment equipment (pretreatment equipment, biological treatment equipment)
5 Sand filtration device (pretreatment device, filtration treatment device)
6 Activated carbon adsorption device (pretreatment device, activated carbon treatment device)
7 accelerated oxidation treatment equipment (pretreatment equipment)
8 Reverse osmosis membrane device 16 Membrane separation activated sludge treatment device (pretreatment device, biological treatment device)
19 Coagulation sedimentation processing equipment (pretreatment equipment)
21 Iron removal manganese removal treatment equipment (pretreatment equipment)
22 Water softening equipment (pretreatment equipment)
23 Electrodeionization equipment W1 Raw water W1a Water to be treated W2 Permeated water (treated water)
W3, W5 Concentrated water W4 Deionized water

Claims (4)

A pretreatment device for removing the impurities contained in the raw water in advance to produce treated water;
A reverse osmosis membrane device that performs a membrane separation process for separating water to be treated into permeated water and concentrated water by a reverse osmosis membrane, and a water treatment system comprising:
The reverse osmosis membrane is a permeate flow when an aqueous solution having a sodium chloride concentration of 1500 mg / L is used as water to be treated in an unfouled state, and is evaluated under the conditions of operating pressure 1 MPa, recovery rate 15%, temperature 25 ° C. and pH 7. A water treatment system, which is a low fouling membrane with a bundle of 1.17 × 10 ⁻⁵ m ³ / m ² / MPa / s or more and a salt removal rate of 99% or more. The reverse osmosis membrane is a permeation flux when an aqueous solution having a sodium chloride concentration of 1500 mg / L is used as water to be treated in a fouling state and is evaluated under the conditions of an operating pressure of 1 MPa, a recovery rate of 15%, a temperature of 25 ° C., and a pH of 7. The water treatment system according to claim 1, wherein the water treatment system is a synthetic polyamide membrane having a salt removal rate of 99% or more and 8.2 × 10 ⁻⁶ m ³ / m ² / MPa / s or more. The pretreatment device includes:
Biological treatment equipment that decomposes and removes organic components contained in raw water by microorganisms;
A coagulation-precipitation treatment device that flocates and removes suspended matter contained in raw water with a coagulant;
A filtration device that captures and removes suspended matter in the raw water with a filtration medium;
Activated carbon treatment equipment that adsorbs and removes organic components and oxidizing substances contained in raw water by activated carbon;
Iron removal and manganese removal treatment equipment that removes dissolved iron and dissolved manganese contained in raw water by insolubilizing them with an oxidizing agent;
An accelerated oxidation treatment device that decomposes and removes organic components contained in raw water by UV irradiation in the presence of an oxidant; and a softening treatment device that adsorbs and removes hardness components contained in raw water by a cation exchange resin. The water treatment system according to claim 1 or 2, comprising any one or more of the above.   The electrode deionization apparatus which performs further the membrane separation process which isolate | separates permeated water into deionized water and concentrated water with an ion exchange membrane in the downstream of the said reverse osmosis membrane apparatus. Water treatment system.

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