JPH06226255A - Device and method for removing material to be adsorbed in liquid - Google Patents

Abstract

PURPOSE:To realize the economical and effective activity of an adsorbent by adsorbing a material to be adsorbed in a permeated liquid in a membrane separation process to a prescribed level before using the adsorbent in an adsorber for treating a liquid contg. the material to be adsorbed of a higher concentration level. CONSTITUTION:A COD contg. feed liquid is mixed with a concentrated liquid 4 in a storage tank 2 to form a concentrated mixed liquid 3 which is injected into a membrane separator (loose RO membrane), where the mixed liquid 3 is separated into a permeated liquid 6 and a concentrated liquid 4. The concentrated liquid 4 is refluxed to the storage tank 2 through a reflux pipe 15 and the permeated liquid 6 attains, through a valve C, a adsorber 7a, where COD is adsorbed, and then is discharged as a treated liquid 9 (the 1st adsorption process). Since the COD concentration of the permeated water 6 is increased with the progress of this treatment, the 2nd adsorption process where valves C, B are closed and valves A, D, E, G are opened immediately before the treated liquid 9 attains a prescribed COD concentration to cause the mixed liquid 3 to directly flow into the adsorber 7a from the storage tank 2 is started and at the point of time when the adsorbent is saturated, it s replaced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for removing substances to be adsorbed in a liquid. As liquid, waste water, water,
The present invention can be used for removal of adsorbed substances in water, such as tap water, biologically treated water thereof, and aggregated treated water of biologically treated water. As the substance to be adsorbed, CO
D component, coloring substance, malodorous component, ammonia nitrogen, nitrate nitrogen, phosphorus and the like can be highly removed. In the present specification, "adsorption" is meant to include ion exchange.
Use the word.

[0002]

2. Description of the Related Art Methods for treating COD components, coloring substances, and malodorous components of wastewater and effluent include biological treatments and physicochemical methods such as filtration, coagulation separation, activated carbon adsorption, photooxidation, and wet oxidation. Are used alone or in combination. Ammoniacal nitrogen is mainly removed from the liquid by a biological nitrification and denitrification method, and phosphorus is mainly removed by a coagulation sedimentation method. As a relatively widely used method for reducing the relatively high concentration of COD remaining in the biologically treated water in the wastewater to a low concentration, the biologically treated water is subjected to coagulation sedimentation treatment and further activated carbon treatment. There is a way. However, even in this method, when COD is removed to an extremely low concentration, the activated carbon reaches the equilibrium adsorption amount in a short time, so the activated carbon must be frequently replaced, which is economically difficult. there were.

Further, an adsorption treatment technology for ammonia nitrogen using zeolite and phosphorus (existing in the form of phosphoric acid) using an ion exchange resin has been researched and developed, but since the same problems as those of the activated carbon have not been solved, they are put to practical use. It is difficult at present. On the other hand, RO (reverse osmosis) membranes have recently been studied as a method for removing COD, ammonia nitrogen and phosphorus at high rates, but an efficient method for treating a concentrated liquid generated by membrane separation has been a concern. . In addition, there is a drawback that the RO membrane separation water concentration also increases as the COD concentration of the concentrated liquid increases.
There are still problems to be solved for practical use of the O film.

[0004]

SUMMARY OF THE INVENTION The present invention solves the drawbacks of the conventional methods for removing adsorbed substances and eliminates the high rates of COD, ammoniacal nitrogen, nitrate nitrogen, phosphorus, etc. remaining in biologically treated water of wastewater. It is an object of the present invention to provide a method and a removal device that efficiently and economically remove even a low concentration.

[0005]

The above problems can be effectively solved by the apparatus and method for removing the substance to be adsorbed in the liquid according to the present invention. That is, (1) a storage tank for storing a stock solution and a concentrated solution of a membrane separator as a mixed solution, and the above-mentioned membrane separator for separating the mixed solution,
An adsorbent for adsorbing a permeated liquid of the membrane separator with an adsorbent, and a device for removing an adsorbed substance comprising a reflux pipe for refluxing the concentrated liquid of the membrane separator to the storage tank, wherein the storage tank comprises: A second adsorption system passage provided with a first adsorption system passage in which the membrane separator and the adsorption device are sequentially connected, and a circulation pipe for introducing a mixed liquid from the storage tank to the adsorption device and circulating it as a circulation liquid to the storage tank. And a device for removing a substance to be adsorbed in a liquid, wherein the first adsorption system passage and the second adsorption system passage are provided so as to be switchable.

(2) An undiluted solution and a concentrated solution of a membrane separator are stored in a storage tank as a mixed solution, the mixed solution is separated by a membrane separator, and the permeated liquid of the membrane separator is an adsorber equipped with an adsorbent. In the method of removing the adsorbed substance, the concentrated liquid is refluxed to the storage tank through a reflux pipe, and the mixed liquid is separated by a membrane separator to adsorb the permeated liquid of the membrane separator. A first adsorption step of performing adsorption treatment by a machine to obtain a treatment liquid, and a second adsorption step of introducing a mixed solution to the adsorption machine and circulating it as a circulating fluid to the storage tank. The method for removing a substance to be adsorbed in a liquid, comprising switching from the first adsorption step to the second adsorption step when the concentration reaches the above.

(3) A storage tank for storing the stock solution and the concentrated solution of the membrane separator as a mixed solution, the membrane separator for separating the mixed solution, and the permeated liquid of the membrane separator are adsorbed by an adsorbent. In an adsorber and a device for removing an adsorbed substance, which comprises a reflux pipe for refluxing the concentrated liquid of the membrane separator to the storage tank, a plurality of the adsorbers are provided following the storage tank and the membrane separator. A first adsorption system path connected in parallel, and a second adsorption system path provided with a circulation pipe for guiding the mixed solution from the storage tank in parallel to the adsorber and circulating it as a circulating liquid to the storage tank,
A device for removing a substance to be adsorbed in a liquid, wherein the first adsorption system path and the second adsorption system path are provided so as to be individually switchable for each adsorber.

(4) An undiluted solution and a concentrated solution of a membrane separator are stored in a storage tank as a mixed solution, the mixed solution is separated by a membrane separator, and the permeated liquid of the membrane separator is an adsorber equipped with an adsorbent. In the method for removing the substance to be adsorbed, the concentrated liquid is refluxed to the storage tank through a reflux pipe, and the mixed liquid is separated by a membrane separator, and the permeated liquid of the membrane separator is paralleled. And a second adsorption step of adsorbing a mixed solution in a plurality of adsorbents arranged in to form a treatment liquid, and a second adsorption step of introducing the mixed liquid in parallel to the adsorber and circulating it as a circulating liquid to the storage tank. When the substance to be adsorbed in the treatment liquid from one or more of the adsorbers reaches a predetermined concentration, the adsorber is switched from the first adsorption step to the second adsorption step, and the other adsorption apparatuses are used. The removal of the substance to be adsorbed in the liquid, characterized in that the first adsorption step is performed in Law.

(5) Storage tank for storing the stock solution and the concentrated solution of the membrane separator as a mixed solution, the membrane separator for separating the mixed solution, and the permeate of the membrane separator is adsorbed by an adsorbent. An adsorbent removal device comprising a permeate adsorber and a reflux pipe for recirculating the concentrated liquid of the membrane separator to the storage tank, wherein the adsorbent for mixed liquid is separate from the adsorber for permeate. And a means for transferring the adsorbent between the adsorber for the permeate and the adsorber for the mixed solution are arranged, and the storage tank, the membrane separator, and the adsorber for the permeate are sequentially connected. A first adsorption system passage; and a second adsorption system passage provided with a circulation pipe for guiding the mixed liquid from the storage tank to the adsorber for the mixed liquid and circulating it as a circulating liquid to the storage tank. Road and second
A device for removing a substance to be adsorbed in a liquid, which is provided so as to be switchable with an adsorption system path.

(6) The stock solution and the concentrated solution of the membrane separator are stored in a storage tank as a mixed solution, and the mixed solution is separated by the membrane separator, and the permeated liquid of the membrane separator is a permeated liquid having an adsorbent. Adsorption treatment with an adsorber for use as a treatment liquid, and the concentrated liquid is returned to the storage tank via a reflux pipe. In the method for removing adsorbed substances, the mixed liquid is separated by a membrane separator and the permeation of the membrane separator is performed. The liquid is adsorbed by the adsorber for the permeated liquid to be treated as a treated liquid, and a second adsorbing process in which the liquid is introduced into the adsorber for the mixed liquid and the circulating liquid is circulated to the storage tank as the circulating liquid. The adsorbent of the permeate adsorber is updated so that the substance to be adsorbed in the treatment liquid does not exceed a predetermined concentration, and the adsorbent discharged from the permeate adsorber is mixed with the adsorbent. The liquid is transferred to an adsorber for liquid and used in the second adsorption step. The method of removing the kimono quality.

The gist of the present invention is that after the adsorbed substance in the permeated liquid in the membrane separation step is adsorbed to a predetermined level by an adsorber equipped with an adsorbent, the adsorbent in the adsorber is adsorbed at a higher concentration level. It is used for the treatment of a liquid containing an adsorbed substance. It should be noted that a plurality of storage tanks, membrane separators, adsorbers, etc., which are installed in series and / or in parallel, are included in the scope of the present invention.

The switching means for switching the first adsorption system and the second adsorption system may be manual, but it is preferable to use a control valve interlocking with a concentration measuring device preferably provided on the discharge side of the adsorber. Further, the concentration measuring means is preferably an automatic measuring device for the concentration of the substance to be adsorbed, but it may be a simple sampling means and may require concentration analysis by manual analysis. Further, when a plurality of adsorbers are arranged in the above-mentioned one series of storage tanks, a plurality of parallel connecting pipes each having a valve for connecting the membrane separator and the plurality of adsorbers are common until reaching the valve. The piping may be. Similarly, the pipes from the storage tank, which is provided between the storage tank and the plurality of adsorbers so that the liquid can be circulated, to the respective valves of the plurality of circulation pipes may be a common pipe.

Next, a method of exchanging the adsorbent will be described.
After the adsorbent of the present invention is used in the first adsorption step, it adsorbs the adsorbed substance in the second adsorption step, and the concentration of the adsorbed substance in the effluent from the adsorbent is predetermined in the first adsorption step. When the predetermined concentration value in the second adsorption step, which is set to a higher concentration value than the concentration value set to, is reached, the adsorbent in the adsorber is replaced.

In the method and apparatus for removing the substance to be adsorbed in the liquid to be treated according to the present invention, after the first adsorption step is stopped and the second adsorption step is switched to, the stock solution and the membrane separation concentrated solution from the storage tank are removed. The adsorbed substance is adsorbed by the adsorbent through the circulation path through the circulation path and the adsorbent is shut off when the concentration value in the adsorber discharge liquid reaches the predetermined concentration value in the second adsorption step. Then, the adsorbent can be replaced, and after the replacement, the adsorbing process can be restarted as the first adsorbing step. Further, continuous treatment can be performed as a deployment as specifically exemplified below.

That is, for example, in the method for removing a substance to be adsorbed in a liquid according to (4) and the apparatus for removing a substance to be adsorbed in a liquid according to (3), an adsorption device among a plurality of adsorption devices is used. Is switched to the second adsorption step, the mixed solution is sent through a circulation path belonging to the adsorber, the adsorbed substance is adsorbed from the mixed solution, and the concentration value in the liquid discharged from the adsorber is changed to the second adsorption step. When the predetermined value of is reached, the adsorbent is exchanged by shutting off the liquid entering and leaving the adsorber.At the time of exchanging the adsorbent, it is not necessary to stop the operation of the adsorbed substance removing device of the present invention.
During this time, the adsorption machines other than the adsorption machine concerned are in the first adsorption step and /
Alternatively, the second adsorption step can be executed to remove the substance to be adsorbed. Of course, the adsorption machine can restart the adsorption process as the first adsorption step after the exchange of the adsorbent is completed.

In the method for removing an adsorbed substance according to (6) and the apparatus for removing an adsorbed substance in a liquid according to (5), the concentration of the adsorbed substance in the treatment liquid is the first adsorption step. Adjust the permeated liquid transfer rate so that it does not exceed the specified value of
And at the same time inserting a new adsorbent into the permeate adsorber,
The used adsorbent is sent from the permeated liquid adsorber to the mixed liquid adsorber to renew the adsorbent in the permeated liquid adsorber. Also in the adsorber for mixed liquid, the adsorbent in which the concentration of the adsorbed substance of the liquid in the circulation pipe discharged from the adsorber for mixed liquid has reached the predetermined value in the second adsorption step is discharged according to the above. At this time, the adsorbent for the permeated liquid may be a single unit, but a plurality of adsorbers may be arranged in parallel, and the renewal time may be rotated according to the durable time of the second adsorption step for continuous treatment. Here, it is not always necessary to provide the same number of adsorbents for mixed liquid as the adsorbents for used liquid that receive the used adsorbent from the adsorber for permeated liquid.

Further, for example, when a permeated liquid adsorber and a mixed liquid adsorber are combined in a one-to-one manner, when the concentration value of the concentration measuring device provided in each processing liquid outflow pipe shows a predetermined value, the concentration Close the valve of the processing liquid outflow pipe with a measuring instrument and the valve of the connecting pipe that is connected to the processing liquid outflow pipe through the adsorber for the permeate, and then mix the adsorbent with the transfer pipe from the adsorber for the permeate. Open the valve of the circulation pipe connected to the adsorber for mixed liquid and connected to the adsorber for mixed liquid, and open the valve of the circulation pipe when the concentration of the substance to be treated in the adsorbent treatment liquid reaches the predetermined value in the second adsorption step. It is advisable to employ a mechanism for closing and adsorbing the adsorbent in the adsorber for mixed liquid.

The feature of the two-stage adsorption method comprising the first adsorption step and the second adsorption step of the present invention is that the adsorbing capacity of the adsorbent after the first adsorption step is more concentrated in the second step as explained in the following action. It is used for adsorption from a liquid containing a substance to be adsorbed. As a result, it is possible to reduce the load on the membrane due to the concentration of the mixed solution, which in turn has the effect of improving the life and efficiency of the entire apparatus. Further, the feature of the two-stage adsorption method of the present invention is that the substance to be adsorbed in the membrane separation permeate is first removed by the adsorbent in the adsorbent for the permeate, and then the adsorbent in the adsorber for the permeate is used for the mixed liquid. The purpose is to transfer the adsorbent to the adsorber and use the adsorbent transferred there for adsorption from a liquid containing a substance to be adsorbed with a higher concentration. Further, the present invention is characterized in that a plurality of adsorbers are arranged in one membrane separation device, and the adsorbers reach a limit where the adsorbent can obtain a predetermined water quality, and the adsorbent needs to be replaced during a period. However, there is no need to stop the operation of the entire processing system. Furthermore, in the present invention, a plurality of adsorbers are provided in a plurality of membrane separators, and each adsorber receives a permeated liquid from each of the plurality of membrane separators from the membrane separator, and thus the first adsorption of the present invention is performed. The process is applied to obtain a treatment liquid, or the permeate from each membrane separator or / and the permeate from a plurality of membrane separators is pooled to perform the first adsorption step of the present invention to obtain treated water. It is only a modification of the present invention to perform the second adsorption step of the present invention on a plurality of adsorbers to remove the substance to be adsorbed from the mixed liquid.

(Operation) FIG. 4 shows an example of the COD adsorption isotherm of activated carbon. As shown in the figure, the lower the equilibrium adsorption concentration (residual concentration), the lower the equilibrium adsorption amount. Therefore, the required amount of activated carbon increases as the COD concentration of the treated water is kept low, but the activated carbon still retains the adsorption capacity in the range where the equilibrium adsorption concentration is high. The present invention was devised by paying attention to the fact that the activated carbon used for the treatment of low-concentration COD-containing water still has a sufficient adsorption capacity in a range where the equilibrium adsorption concentration is high. That is, the life of the adsorbent can be extended by reusing it for a plurality of treatments having different treatment target limits. Adsorption of ammoniacal nitrogen by zeolite (ion exchange),
The adsorption of phosphorus by the ion exchanger (resin) also shows the same tendency as activated carbon.

Embodiments of the present invention will be specifically described below with reference to the drawings. However, the present invention is not limited by the description of the embodiments below. First, one embodiment of the present invention will be specifically described with reference to FIG. An undiluted solution containing COD (which is obtained by coagulating wastewater activated sludge treated water and then filtering with a microfilter) is mixed with a concentrated solution 4 in a storage tank 2 to form a concentrated mixed solution 3
As a result, it is pressed into a loose RO membrane (membrane separator) 5 having a NaCl blocking rate of 50%. The loose RO film has a lower NaCl blocking rate than other RO films and is about 80% or less. The mixture 3 injected under pressure is separated into the permeate 6 and the concentrate 4, the concentrate 4 is returned to the storage tank 2 through the reflux pipe 15, and the permeate 6 is passed through the valve C and the adsorber in the activated carbon adsorption step. COD is adsorbed by 7a and discharged as the processing liquid 9 via the valve B. That is, it is the first adsorption process belonging to the adsorption device 7a. In this first adsorption step, the valves C and B are open and the valves A and D are closed. In the first adsorption step, since the mixed solution is separated and concentrated, the COD concentration of the mixed solution 3 and the concentrated solution 4 increases as the amount of treated water increases, and the C of the permeated water 6 increases.
The OD concentration also gradually increases.

Immediately before the treatment liquid 9 reaches the predetermined COD concentration, the valves C and B are closed, the valves A, D, E and G are opened, and the permeate 6 is adsorbed on the activated carbon via the valve E. COD is adsorbed by the adsorber 7b in the process and discharged as the treatment liquid 9 via the valve B. That is, the first adsorption process of the adsorption device 7b is started. On the other hand, when the valves A and D are opened, the second adsorption step in which the mixed liquid 3 flows from the storage tank 2 more directly into the adsorber 7a through the valve A to adsorb COD is started. (Second adsorption step of adsorption device 7a). The increase in the COD concentration in the storage tank 2 is reduced or decreased. Therefore, at this time, the second adsorption process belonging to the adsorption device 7 and the first adsorption process belonging to the adsorption device 7b are operating in parallel, the valves E, G, A and D are open and the valves C and B are closed. is there. The permeated liquid 6 switched to the adsorber 7b system starts to adsorb COD through the valve E in the adsorber 7b in the activated carbon adsorption step. In the second adsorption step belonging to the adsorber 7a, when the circulating liquid 14 reaches a predetermined concentration, for example, when the activated carbon of the adsorber 7a is saturated with the COD component of the mixed liquid 3, the valves A and D are closed to activate the activated carbon. Will be exchanged. At the time of activated carbon replacement, valves A, B, C and D are all closed. The adsorber 7a, which has completed the exchange of activated carbon, opens the valves A and D to restart the first adsorption step.

Next, in the first adsorption step belonging to the adsorber 7b, the valves E and G are closed, the valves F and H are opened immediately before the treated water 9 reaches a predetermined COD concentration, and the mixed solution 3 is opened. F
Water is passed to the adsorber 7b via the valve and circulated to the storage tank 2 via the valve H. Here, if the first adsorption process belonging to the adsorption device 7a is restarted, the second adsorption process belonging to the adsorption device 7b and the first adsorption process belonging to the adsorption device 7a are operating in parallel at this time, and the valve F , H, C and B are open and others are closed. In the second adsorption step belonging to the adsorber 7b, when the activated carbon of the adsorber 7b becomes saturated with, for example, the COD component of the mixed liquid 3, the valves F and H are closed and the activated carbon is exchanged. At the time of activated carbon replacement, the valves E, G, F and H are all closed.

The above processing steps are sequentially repeated. That is, after the RO-treated water and the concentrated water are sequentially treated, the activated carbon is exchanged alternately at different times. At this time, the treated water 9 is continuously discharged if the first adsorption step of any of the adsorption machines is in progress. In the above description of the treatment process, an example in which the first adsorption process operates alternately in the case of two adsorption devices is shown, but there are more adsorption devices and even if the first adsorption process starts rather randomly. As long as the first adsorption step is continuous as a whole, there is no significant difference in the total sum of the flow rates, and there is little overlap in the exchange of the activated carbon, the plurality of treatment liquid outflow pipes and the plurality of circulation pipes 14 are filled with the substances to be adsorbed. When a measured value reaches a predetermined value by operating a valve such as a concentration measuring instrument, the valve is operated according to the above-mentioned rules, and when the activated carbon is saturated with the COD component of the mixed solution 3, the activated carbon is appropriately replaced. By doing so, it is possible to continue the removal of the liquid to be adsorbed within the range of the capacity of the membrane separator. Of course, the treated water 9 may be discharged intermittently, and the adsorber does not necessarily have to be rotated.

Although not shown in FIG. 1, the circulating liquid 1 of the second adsorption step during the passage of water through the second adsorption step of the mixed liquid
4 is not circulated in the storage tank 2 and is mixed with the permeated water 6 and is put into the first step belonging to another adsorber to perform adsorption treatment.
It is also possible to obtain Note that it is preferable to use an automatic COD densitometer that converts the absorption value of UV (ultraviolet) into the COD concentration for detecting the COD concentration because the operation can be automatically controlled.

Next, another embodiment of the present invention will be described with reference to FIG. The stock solution 1 containing COD (the activated sludge treated water of waste water filtered by a microfilter) is mixed with the concentrated solution 4 in the storage tank 2, and the mixed solution 3 is a loose RO membrane (membrane separator having a NaCl blocking rate of 50%). ) Pressed into 5,
The permeated liquid 6 and the concentrated liquid 4 are separated, the concentrated liquid 4 is returned to the storage tank 2, and the permeated liquid 6 is adsorbed with COD by the adsorbent 8a for the permeated liquid in the activated carbon adsorption step via the valve C, and the valve B It is discharged as a processing liquid 9 via. In the adsorbent 8a for the permeated liquid in the activated carbon adsorption step, fresh activated carbon is charged batchwise or continuously so that the treated water 9 does not exceed the predetermined COD concentration, and the waste activated carbon 10 is transferred to the adsorber 8b for mixed liquid.
The mixed liquid 3 is sent to the adsorber 8b for mixed liquid through the circulation pipe 13, and is circulated as the circulating liquid 14 back to the storage tank 2 through the circulation pipe 15 to remove the COD component in the adsorber 8b for mixed liquid. It

Although not shown, part of the effluent of the adsorber 8b for mixed liquid is not returned to the storage tank 2 and the permeated liquid 6 is used.
Alternatively, the treated water 9 may be obtained by mixing the permeated liquid 6 with the permeated liquid 12 through the communication pipe 12 through which the COD component passes and removing the COD component by the permeated liquid adsorber 8a. In the present invention, any adsorbent that has a physicochemical function such as activated carbon, zeolite, or an ion exchanger can be used. Further, any substance that is adsorbed (including ion exchange) can be targeted for removal. Any membrane can be used as long as it can separate a part of the substance to be adsorbed.

[0027]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited thereto. (Example 1) Coagulation-treated water of undiluted denitrified treated human waste was separated by an ultrafiltration membrane having a molecular weight cut-off of 100,000 as raw water, and COD concentration of 180 mg / liter of raw water was treated with activated carbon. In order to reduce the amount to 0 mg / liter or less, the results of performing the treatment by the treatment procedure shown in FIG. 1 of the present invention will be described. The equipment and processing conditions are shown in Table 1 below. The permeated liquid and the mixed liquid were switched to each activated carbon adsorption tower, and the used activated carbon was discharged automatically by using the measured value by a COD meter using UV as an index.

Table 1 Apparatus: Raw water tank Effective volume: 1.0 m ³ Loose RO membrane: Cellulose acetate made NaCl rejection rate 50% COD removal rate 90% Activated carbon adsorption tower: Diameter 300 mm, height 2000 m
m 2-3 mm Coal-based granular activated carbon used Filling amount: 50 kg / 2 tower (25 kg / 1 tower) Treatment condition: Treated water amount: 1.0 m ³ / day Loose RO membrane: (Inlet pressure) 15-20 kgf / c
m ² Activated carbon flow rate: (Downflow) SV 1 / hour

(Comparative Example 1) As a comparative example, the permeated liquid was passed through an adsorption tower having a packed amount of activated carbon of 50 kg by the conventional treatment procedure shown in FIG.

Results of Implementation Example 1 Amount of treated water during continuous operation in steady state: 3.0 m ³
/ Kg (activated carbon) In the case of Comparative Example 1 Treated water amount when the water flow rate is 9 m ³ or more: 0.18 m
³ / kg (activated carbon) (COD concentration in the treated water at the time of passing water 9m ³ water communicating is 3.
0 mg / liter)

(Example 2) In order to reduce the COD concentration of sand filtration water (COD concentration 20 mg / liter) of biologically treated water of domestic wastewater to 1 mg / liter or less, the treatment flow of FIG. 2 of the embodiment of the present invention is used. The treatment was carried out. Table 2 below shows the apparatus and processing conditions.

Table 2 Apparatus: Raw water tank effective volume: 1.0 m ³ loose RO membrane: Cellulose acetate made NaCl rejection rate 50% COD removal rate 90% Activated carbon adsorption tower: Upflow type diameter 300 mm, height 2000 mm 2-3 mm Use of coal-based granular activated carbon Filling amount: 50 kg / 2 towers (25 kg / 1 tower) Activated carbon filling port Upper part of activated carbon discharging port Bottom part of processing condition: amount of treated water: 1.0 m ³ / day Loose RO membrane: (inlet pressure) 15- 20 kgf / c
m ² Activated carbon flow rate: (Downflow) SV 1 / hour

0.25 kg of activated carbon from the activated carbon adsorption tower A (adsorbent for permeated liquid) is drawn from the bottom of the tower every day and charged into the activated carbon adsorption step B (adsorbent for mixed solution) from the top. Charcoal was charged daily from the top of the tower with the withdrawal. With respect to the activated carbon in the activated carbon adsorption step B, from the time when the filling amount became the same as that of the activated carbon adsorption tower A, the daily equivalent of the activated carbon was withdrawn from the bottom every day.

(Comparative Example 2) As a comparative example, permeated water was passed through an adsorption tower having an activated carbon filling amount of 50 kg in the treatment flow shown in FIG.

Implementation Results In the case of Example 2, the COD concentration of the treated water was 1 mg / in continuous operation for 200 days.
Never exceeded liters. Amount of treated water during continuous operation in steady state 4.0m
³ / kg (activated carbon) In the case of Comparative Example 2, after 70 days, the COD concentration of the treated water exceeded 1 mg / liter, so 50 kg of new coal was newly charged, but after 35 days, the COD concentration of the treated water was 1 mg / liter again. Over liter.

This is because, in the comparative example, the COD concentration of the concentrated mixed liquid in the raw water tank increased with time, and the COD concentration of the permeate also increased following it. Amount of treated water per unit weight of activated carbon for 70 days 1.40
m ³ / kg (activated carbon) (= 70m ³ / 50kg activated carbon) of the activated carbon per unit weight of 35-day treatment water 0.70
m was ³ / kg (activated carbon) (= 35m ³ / 50kg activated carbon).

(Example 3) In order to reduce the ammonia nitrogen concentration of sand filter water (ammonia nitrogen concentration 10 mg / liter) of biologically treated water of domestic waste water to 1 mg / liter or less, natural zeolite is used instead of activated carbon. The treatment was carried out by filling the adsorption tower of FIG. 2 of the embodiment of the invention. The equipment and processing conditions are shown in Table 3 below.

Table 3 Apparatus: Raw water tank effective volume: 1.0 m ³ loose RO membrane: Cellulose acetate made NaCl rejection rate 50%, ammonia nitrogen concentration removal rate 80% Zeolite adsorption tower A: Upflow type (for permeate) Adsorption machine) Diameter 300mm, height 200
0 mm 1.0-1.5 mm Zeolite Filling amount: 50 kg Zeolite filling port Upper column zeolite discharging port Lower column zeolite adsorption column B: Upflow type (adsorption machine for mixing) Diameter 200 mm, height 200
0 mm Zeolite filling port Upper part of the tower Zeolite outlet port Bottom part Treatment condition: Treated water amount: 1.0 m ³ / day Loose RO membrane: (Inlet pressure) 15 to 20 kgf /
cm ² Zeolite water flow rate: SV 3 / hour

1.4 kg of zeolite in the zeolite adsorption tower A was drawn from the bottom of the tower every day, and the zeolite adsorption step B was filled from the top with new zeolite from the top of the tower every day. With respect to the zeolite in the zeolite adsorption step B, from the time when the packed amount became the same as that of the zeolite adsorption tower A, a daily equivalent of the packed amount of zeolite was extracted from the bottom every day.

(Comparative Example 3) As a comparative example, permeated water was passed through an adsorption tower having a zeolite filling amount of 50 kg in the process flow shown in FIG.

Results of Example 3 In Example 3, the ammonia nitrogen concentration in the treated water did not exceed 1 mg / liter during continuous operation for 200 days. Treated water volume during continuous operation in steady state: 0.7 m ³
/ Kg zeolite (= 1.0 m ³ /1.4 kg zeolite) In the case of Comparative Example 3 After 7 days, the ammonia nitrogen concentration in the treated water exceeded 1 mg / liter, and thus 50 kg of new zeolite was charged, but after 35 days Again, the ammonia nitrogen concentration in the treated water exceeded 1 mg / liter.

This is because in the comparative example, the concentration of ammonia nitrogen in the concentrated mixed liquid in the raw water tank increased with time, and the concentration of ammonia nitrogen in the permeate also increased accordingly. Of treated water 1.40 m ³ / kg of zeolite per unit weight of 7 days (zeolites) (= 70m ^3/50 kg zeolite) 5 days treatment water 0.10 m ³ / kg (zeolite) per zeolite unit weight (= 35m ³ / 50kg zeolite)

[0043]

【The invention's effect】

(1) Since the adsorbent is again used for the adsorption treatment of the liquid containing the adsorbent having a higher concentration, the adsorbent adsorbed amount per unit weight of the adsorbent increases, so that the adsorbent is economically and efficiently used. Can be used. (2) Membrane Separation Step Since the concentration of the substance to be adsorbed in the concentrated mixed liquid in the first stage can be reduced by the adsorbent that has been used in the permeate treatment, the concentration of the substance to be adsorbed in the membrane permeate water is lowered. Therefore, the load of the substance to be adsorbed on the adsorption step is reduced, so that the separation membrane and the adsorbent can be used for a long time. (3) It is possible to solve the problem of disposal of the concentrated liquid generated by the membrane separation.

[Brief description of drawings]

FIG. 1 is an explanatory view of an example of an adsorbed substance removing device of the present invention.

FIG. 2 is an explanatory view of another example of the adsorbed substance removing device of the present invention.

FIG. 3 is an explanatory view of a typical example of a conventional device for removing an adsorbed substance.

FIG. 4 is a graph showing an example of COD adsorption isotherm of activated carbon.

[Explanation of symbols]

 1 stock solution 2 storage tank 3 mixed solution 4 concentrated solution 5 membrane separator 6 permeate 7a adsorber 7b adsorber 8a permeate adsorber 8b mixed solution adsorber 9 treatment liquid 10 waste activated carbon 11 press-fitting pump 12 connecting pipe 13 circulation Pipe 14 Circulating liquid 15 Reflux pipe 16 Adsorbent transfer pipe

Claims (6)

[Claims] 1. A storage tank for storing a stock solution and a concentrated solution of a membrane separator as a mixed solution, the membrane separator for separating the mixed solution, and an adsorption for adsorbing the permeated liquid of the membrane separator with an adsorbent. And an adsorbent substance removal device comprising a reflux pipe for refluxing the concentrated liquid of the membrane separator to the storage tank, wherein a first adsorption in which the storage tank, the membrane separator, and the adsorber are sequentially connected. A first adsorption system passage and a second adsorption system passage provided with a circulation pipe for guiding the mixed liquid from the storage tank to the adsorption machine and circulating it as a circulating liquid to the storage tank. An apparatus for removing substances to be adsorbed in a liquid, which is provided so as to be switchable between and. 2. The stock solution and the concentrated solution of the membrane separator are stored as a mixed solution in a storage tank, and the mixed solution is separated by the membrane separator,
The permeated liquid of the membrane separator is subjected to adsorption treatment with an adsorber equipped with an adsorbent to obtain a treated liquid, and the concentrated liquid is refluxed to the storage tank through a reflux pipe. A first adsorption step in which the permeated liquid of the membrane separator is subjected to adsorption treatment in an adsorber to form a treatment liquid, and a second liquid mixture is introduced into the adsorber and circulated to the storage tank as a circulating liquid. A method for removing a substance to be adsorbed in a liquid, which comprises an adsorption step, and switches from the first adsorption step to the second adsorption step when the adsorption substance in the treatment liquid reaches a predetermined concentration. 3. A storage tank for storing the stock solution and the concentrated solution of the membrane separator as a mixed solution, the membrane separator for separating the mixed solution, and the adsorption for adsorbing the permeate of the membrane separator with an adsorbent. And a device for removing an adsorbed substance comprising a reflux pipe for refluxing the concentrated liquid of the membrane separator to the storage tank, wherein a plurality of the adsorbers are arranged in parallel after the storage tank and the membrane separator. A first adsorption system passage connected to the first adsorption system passage, and a second adsorption system passage provided with a circulation pipe for introducing the mixed liquid from the storage tank in parallel to the adsorption machine and circulating it as a circulation liquid to the storage tank. A device for removing a substance to be adsorbed in a liquid, wherein an adsorption system path and a second adsorption system path are provided so as to be individually switchable for each adsorber. 4. A stock solution and a concentrated solution of a membrane separator are stored as a mixed solution in a storage tank, and the mixed solution is separated by the membrane separator,
The permeated liquid of the membrane separator is subjected to adsorption treatment with an adsorber equipped with an adsorbent to obtain a treated liquid, and the concentrated liquid is refluxed to the storage tank through a reflux pipe. A first adsorption step in which the permeate of the membrane separator is adsorbed by a plurality of adsorbers arranged in parallel to obtain a treatment liquid; and a circulating liquid which introduces the mixed liquid into the adsorber in parallel. And a second adsorption step of circulating the adsorbent to the storage tank. When a substance to be adsorbed in the treatment liquid from one or more of the adsorbers reaches a predetermined concentration, A method for removing a substance to be adsorbed in a liquid, comprising switching from an adsorption step to the second adsorption step and performing the first adsorption step in other adsorbers. 5. A storage tank for storing the stock solution and the concentrated solution of the membrane separator as a mixed solution, the membrane separator for separating the mixed solution, and the permeate of the membrane separator is adsorbed by an adsorbent. In a device for removing an adsorbed substance, which comprises a permeate adsorber and a reflux pipe for refluxing the concentrated liquid of the membrane separator to the storage tank, a mixture adsorber separate from the permeate adsorber is used. A transfer means for the adsorbent is provided between the adsorber for permeate and the adsorber for mixed solution, and the storage tank, the membrane separator, and the adsorber for permeate are sequentially connected. A first adsorption system passage, and a second adsorption system passage provided with a circulation pipe for guiding the mixed solution from the storage tank to the adsorber for the mixed solution and circulating it as a circulating liquid to the storage tank. Of the substance to be adsorbed in the liquid, characterized in that it is provided so as to be switchable between the second adsorption system path and the second adsorption system path. apparatus. 6. A stock solution and a concentrated solution of the membrane separator are stored as a mixed solution in a storage tank, and the mixed solution is separated by the membrane separator,
The permeate of the membrane separator is adsorbed by a permeate adsorber equipped with an adsorbent to obtain a treatment liquid, and the concentrated liquid is refluxed to the storage tank through a reflux pipe. A first adsorption step in which the liquid is separated by a membrane separator and the permeated liquid of the membrane separator is adsorbed by the adsorbent for the permeated liquid to be a treated liquid, and an adsorber for a mixed liquid in which a mixed liquid is separately provided. And a second adsorption step of circulating it as a circulating liquid to the storage tank, and updating the adsorbent of the adsorbent for the permeated liquid so that the substance to be adsorbed in the treatment liquid does not exceed a predetermined concentration. A method for removing a substance to be adsorbed in a liquid, wherein the adsorbent discharged from the permeated liquid adsorber is transferred to the mixed liquid adsorber and used in the second adsorption step.