JP3932763B2 - Operation method of coagulation treatment apparatus and coagulation treatment apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of operating a coagulation treatment apparatus and coagulation treatment apparatus, and more particularly, a permeation flux of a membrane when solid-liquid separation is performed by a membrane separation apparatus after adding a coagulant to raw water and performing an aggregation reaction in a coagulation tank. The present invention relates to an operation method of an aggregating apparatus and an aggregating apparatus that are intended to stabilize (flux) and reduce the amount of flocculant added.
[0002]
[Prior art]
Conventionally, as shown in FIG. 2, PAC (polyaluminum chloride) and sulfuric acid band (Al ₂ (SO ₄ ) ₃ ) are used as turbidity treatment technology for river water, ground water, lake water, industrial water, or various wastewaters. Then, a flocculant such as ferric chloride (FeCl ₃ ) and a pH adjuster as necessary are added and mixed in the line mixer 41, and then agglomeration reaction is performed in the agglomeration tank 42 to generate agglomerated flocs. There is known a coagulation filtration method in which a coagulation treatment liquid containing floc is fed to a membrane separation device 43 by a pump P and solid-liquid separation is performed. In this case, the membrane separation device 43 serving as the solid-liquid separation means periodically uses membrane permeated water (treated water) or pressurized air for backwashing (additional air in FIG. 2) for the purpose of separating the SS adhering to the membrane surface. Backwashing is performed in which compressed air) flows back from the permeate side of the membrane separation device 43.
[0003]
In this backwashing process, the pressurized membrane permeate or air is allowed to flow back while the pump P is operated without stopping, and the backwash wastewater is discharged out of the system. During this time, the aggregation treatment liquid that has passed through the pump P is returned to the aggregation tank 42.
[0004]
However, even if the membrane separation process is performed while performing backwashing in this way, by continuing the operation, the flux gradually decreases due to clogging of the membrane. In this case, the operation of the membrane separation apparatus Is stopped and cleaning with chemicals is performed.
[0005]
[Problems to be solved by the invention]
However, in the conventional aggregating apparatus as shown in FIG. 2, the flux is significantly reduced due to clogging of the film, and the frequency of chemical cleaning for recovery of the flux is high. There were problems such as decline.
[0006]
In the conventional aggregating apparatus, this clogging of the film is considered to be caused by the following.
[0007]
That is, in the conventional aggregating apparatus, the aggregating treatment liquid that has passed through the pump P is returned to the aggregating tank 42 in the backwashing process. At this time, the aggregated floc generated in the aggregation tank 42 is destroyed by passing through the pump P, and the floc diameter is reduced. For this reason, by repeating backwashing, the broken flocs in the aggregation tank 42 increase, and these flocs are further refined by passing through the pump P. Then, the particles refined to approximately the same size as the pore diameter of the membrane of the membrane separation device 43 clog the pores of the membrane so as to bite, and clogging is difficult to peel off by backwashing. This clogging proceeds and the flux decreases.
[0008]
In order to reduce such clogging due to fine particles, the water that has passed through the pump P in the backwashing process is not returned to the flocculation tank 42, or the amount of flocculant added is increased, thereby reflocculating the fine flocs. However, in this case, there is a problem in that the water recovery rate decreases or the amount of chemicals used increases, which is not preferable.
[0009]
The present invention solves the above-mentioned conventional problems, stabilizes the flux by preventing clogging of the membrane in the case of solid-liquid separation with a membrane separation device after adding a flocculant to raw water and performing agglomeration reaction in a coagulation tank. It is an object of the present invention to provide a method for operating a coagulation treatment apparatus and a coagulation treatment apparatus capable of improving the water recovery rate and reducing the amount of coagulant added for coagulation treatment.
[0010]
[Means for Solving the Problems]
The operation method of the flocculation treatment apparatus of the present invention is to add a flocculant to raw water and cause a flocculation reaction in the flocculation tank, and slowly stir the effluent water from the flocculation tank in the floc generation tank to generate floc, An agglomeration treatment method comprising a coagulation treatment step for performing solid-liquid separation with a separation device and a backwashing step for backwashing the membrane separation device, wherein the coagulation treatment step performs solid-liquid separation with the membrane separation device. there are a, together with the water floc generation tank is pumped out, separated into the concentrated water and permeated water to deliver water discharge of the pump to the membrane separation device, the concentrated water, the floc produced In the backwashing step of returning to the agglomeration tank without flowing into the tank and backwashing the membrane separator, the agglomeration without allowing the entire amount of water discharged from the pump to flow into the flock production tank It is characterized by being returned to the tank.
[0011]
The flocculation treatment apparatus of the present invention includes a flocculation tank that performs a flocculation reaction by adding a flocculating agent to raw water, a floc generation tank that slowly stirs outflow water from the flocculation tank to generate a flock, and the floc generation tank. A flocculation apparatus having a membrane separation device that separates the effluent from the flocs into a concentrated water and a permeate, and a feed path comprising a pump for feeding the effluent from the flock production tank to the membrane separator; A circulation path that branches off from the feed path downstream of the pump and communicates with the coagulation tank, and a return path that communicates the concentrated water outlet of the membrane separator and the coagulation tank. And
[0012]
In the present invention, a floc generating tank is provided, and among the water that has passed through the pump, the water that is not supplied to the membrane separation device during backwashing is returned to the aggregating tank, re-aggregated in the aggregating tank, and further coarse in the flock generating tank Make it. By coarsening the fine floc destroyed by the pump in this way, the flow of fine particles into the membrane separation device is prevented, thereby preventing the membrane from being blocked due to the fine particles.
[0013]
In addition, the concentrated water of the membrane separator is returned to the coagulation tank and circulated to increase the water recovery rate, and by adding the membrane concentrated water enriched with fine flocs to the coagulation tank, Generation of flocs in the coagulation tank can be promoted using the flocs as nuclei, whereby the required amount of flocculant added can be reduced.
[0014]
In the present invention, when solid-liquid separation is performed in the membrane separation device, a part of the pump discharge water may be supplied to the membrane separation device, and the remaining portion may be circulated to the coagulation tank. The water that has passed through the pump is returned to the coagulation tank, so that the fine flocs can be re-agglomerated and flocked.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail.
[0016]
FIG. 1 is a system diagram of an aggregating apparatus according to an embodiment of the present invention.
[0017]
In Figure 1, 1 is a strainer, 2 flocculation tank, 3 floc formation tank, 4 is a membrane separation device, 2M, 3M of agitators, 2A is a pH meter, 3A level switch, _{V 0} is the flow rate control valve, _{V 1} ~V ₅ is an on-off valve. A pipe 106 provided with a pump P for taking out water from the floc generating tank 3 branches into pipes 107 and 108, and backwash drainage is discharged from between the valve V _{1 of the} pipe 108 and the inlet of the membrane separation device 4. The piping 110 for branching is provided.
[0018]
At the time of raw water aggregation and membrane filtration operation (coagulation treatment step), the valves V ₁ , V ₂ , V _{3 are} opened, and the valves V ₄ , V _{5 are} closed.
[0019]
The raw water introduced from the pipe 101 is first dust-removed by the strainer 1 of about 40 to 80 mesh, and then introduced from the pipe 102 to the agglomeration tank (hereinafter sometimes referred to as “rapid stirring tank”) 2 and from the pipe 103. The flocculation treatment is performed with a flocculant such as PAC and a pH adjuster added as necessary from the pipe 104.
[0020]
In this rapid agitation tank 2, the membrane concentrated water of the subsequent membrane separation device 4 and the return water from the floc generating tank (hereinafter sometimes referred to as “slow agitation tank”) 3 are introduced through pipes 109 and 107, respectively. The raw water is agglomerated by stirring with the added flocculant together with these waters, preferably at a relatively high stirring speed of about 200 to 300 rpm. The residence time of the rapid stirring tank 2 is preferably 1 minute or longer, particularly 3 to 5 minutes.
[0021]
The flocs refined by passing through the pump P do not re-aggregate or flock even if left standing as they are, but can be re-agglomerated and flocked by vigorously stirring for 1 minute or more by rapid stirring. .
[0022]
In the present invention, the above stirring conditions in the rapid stirring tank 2 are extremely important in order to reflocculate and flocify the fine particles in the return water from the slow stirring tank 3 and the membrane concentrated water, and the stirring speed is in the above range. If it is slower than that, reaggregation and flocification take a long time and a long residence time is not preferable.
[0023]
As the flocculant used for the flocculation treatment in the rapid stirring tank 2, polyaluminum chloride (PAC), aluminum chloride (AlCl ₃ ), sulfuric acid band (Al ₂ (SO ₄ ) ₃ ), other aluminum hydroxide (Al (OH)) ₃ ) or an aluminum salt such as aluminum oxide (Al ₂ O ₃ ) dissolved in hydrochloric acid (HCl) or sulfuric acid (H ₂ SO ₄ ), ferric chloride (FeCl ₃ ), ferric sulfate (Fe ₂ (SO ₄ ) ₃ ), one or more of iron salts such as ferrous sulfate (FeSO ₄ ), etc., preferably PAC can be used, and the amount used is usually 5 to 5 relative to the raw water. Although it is 500 mg / L, in the present invention, it is possible to increase the agglomeration efficiency by returning the membrane concentrated water in which fine flocs, which are the core of agglomeration and flocking, are concentrated, to the rapid stirring tank 2. Therefore, a good coagulation effect can be obtained even with a relatively small coagulant addition amount of about 5 to 40 mg / L with respect to the raw water.
[0024]
In the raw water aggregation treatment, sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (Ca (OH) ₂ ), calcium oxide (CaO), ammonium hydroxide ( An alkali such as NH ₄ OH) or a mineral acid such as hydrochloric acid (HCl), sulfuric acid (H ₂ SO ₄ ) or nitric acid (HNO ₃ ) is added to adjust the pH to about 6.0 to 10.
[0025]
The effluent water from the rapid stirring tank 2 is then introduced into the slow stirring tank 3 through the pipe 105 and is preferably stirred at a relatively slow stirring speed of about 50 to 100 rpm, whereby the floc becomes coarse. The stirring in the slow stirring tank 3 is not necessarily required, and the stirrer may be omitted when a swirling flow can be formed in the tank using the inflowing water flow. The residence time in the slow stirring tank 3 is preferably 5 minutes or longer, particularly 10 to 20 minutes.
[0026]
The treated water in the slow stirring tank 3 is supplied to the membrane separation device 4 through the pipes 106 and 108 by the pump P and subjected to membrane filtration treatment. The membrane permeated water is discharged out of the system from the pipe 111 as treated water, The membrane concentrated water is returned to the rapid stirring tank 2 via the pipe 109.
[0027]
By circulating the membrane concentrated water 2 in this way, the water recovery rate can be increased. In addition, the fine flocs in the membrane concentrated water are re-agglomerated and flocked in the rapid agitation tank 2 when circulating the membrane concentrated water. This prevents the membrane of the membrane separation device 4 from becoming clogged. Furthermore, as described above, the membrane-enriched water in which the fine flocs are concentrated is returned to the rapid agitation tank 2, so that in the rapid agitation tank 2, the fine flocs in the membrane-enriched water function as the core of the aggregation treatment. Good coagulation treatment can be performed with a small amount of coagulant added.
[0028]
In the membrane filtration operation of the membrane separator 4, a part of the discharge water of the pump P may be supplied to the membrane separator 4, and the remaining portion may be circulated through the pipe 107 to the rapid stirring tank 2. The total amount of discharged water may be supplied to the membrane separation device 4. Even when only a part of the water discharged from the pump P is fed to the membrane separation device 4, the remaining part of the water that has passed through the pump is returned to the rapid agitation tank 2 to reduce the fine flocs contained in this water. Effectively re-aggregates and flocs.
[0029]
In the backwashing process for backwashing the membrane separation device 4, the valves V ₁ , V ₂ , V _{3 are} closed and the valves V ₄ , V _{5 are} opened, and the backwash air is permeated through the membrane separation device 4 from the pipe 112. It press-fits from the water side and discharges backwash waste water from the pipe 110.
[0030]
At this time, the pump P is operating, and the discharge water of the pump P is fed to the rapid stirring tank 2 through the pipe 107. As a result, flocs in the return water from the slow stirring tank 3 that have been refined by passing through the pump P are re-aggregated and flocked in the rapid stirring tank 2, so that the flocs can be refined by repeating backwashing. Clogging of the membrane of the membrane separation device 4 due to the conversion is prevented.
[0031]
In addition, an inorganic flocculant or an organic polymer flocculant may be added to the slow stirring tank 3 as necessary.
[0032]
In the present invention, an MF (microfiltration) membrane or a UF (ultrafiltration) membrane is preferably used as the separation membrane of the membrane separation device 4. There are no particular restrictions on the material and type of the membrane, and the installation type may be either vertical or horizontal, but a spiral-type module is preferred, and in particular, no water collection pipe is required and permeate flow resistance is low. Therefore, a spiral membrane module as shown in FIGS.
[0033]
Moreover, it is preferable that the membrane separation apparatus 4 performs backwashing periodically by backflowing air or permeated water (treated water) after a predetermined time of filtration treatment, and backwashing is performed for filtration of 4 to 15 minutes. It is preferable to carry out at a frequency of about 30 to 60 seconds.
[0034]
A spiral membrane module suitable as a membrane separation apparatus of the present invention will be described below with reference to FIGS.
[0035]
FIG. 4A is a perspective view of a single bag-like membrane used in the spiral membrane module and a shaft around which the bag-like membrane is wound. 4B and 4C are cross-sectional views taken along lines BB and CC in FIG. 4A, respectively. FIG. 5 is a cross-sectional view showing a method of winding a bag-like membrane around a shaft, FIG. 6 is a perspective view showing an engagement relationship between a wound body and a socket, and FIG. 7 is a side view of a spiral membrane module.
[0036]
The bag-like film 10 used in this embodiment has a square or rectangular shape, and includes a first side part 11, a second side part 12, a third side part 13 and a fourth side part. 14. This bag-like membrane 10 is formed by folding a long separation membrane film into two at the second side portion 12 and separating the separation membrane films folded at the first side portion 11 and the third side portion 13 together. It is bonded with an adhesive or the like, and a part of the fourth side portion 14 has a bag shape that is an open portion without bonding.
[0037]
From the middle of the fourth side portion 14 to the third side portion 13, the separation membrane films of the bag-like membrane 10 are not adhered to each other, and an open portion 30 for permeate outflow is formed. Moreover, the separation membrane films of the bag-like membrane 10 are bonded to each other from the middle of the fourth side portion 14 to the first side portion 11, thereby forming a closed portion 31 that prevents the permeated water from flowing out. Yes.
[0038]
A channel material (for example, made of a mesh spacer) 15 is inserted and disposed in the bag-like film 10. The bag-like membrane 10 is not limited to one long film folded in two at the second side portion 12 portion, and two separation membrane films are overlapped to form the first side portion 11, A part of the second side part 12, the third side part 13, and the fourth side part 14 may be bonded.
[0039]
An adhesive 16 is attached to one surface of the bag-like film 10 and adhesives 17 and 18 are attached to the other surface, and the bag-like film 10 is wound around the shaft 20. The adhesive 16 is attached along the first side portion 16, and the adhesive 17 is attached along the third side portion 13. The adhesive 18 is attached along the open portion 30 for flowing out the permeated water from the midway portion in the longitudinal direction of the fourth side portion 14 to the third side portion 13.
[0040]
By winding a plurality of bag-like membranes 10 around the shaft 20, the overlapping bag-like membranes 10 are joined in a watertight manner at the portions of the adhesives 16, 17 and 18. Thereby, the raw | natural water flow path through which raw | natural water (and concentrated water) flows is comprised between bag-like membranes 10,10 .... When the adhesive 18 is cured, an open portion for outflow of raw water (concentrated water) is formed on the inner peripheral side and a closed portion for preventing raw water outflow is formed on the outer peripheral side on the rear end surface of the wound body. The
[0041]
The fin 19 is extended from the boundary part of the open part 30 for permeate water outflow and the closed part 31 for permeate water outflow prevention of this 4th side part 14 toward the back of a wound body. The fins 19 are made of, for example, a synthetic resin film or sheet, and are preferably bonded to the bag-like film 10 by adhesion or the like.
[0042]
As shown in FIG. 6, the wound body 24 is formed by winding the bag-like membranes 10, 10... Around the shaft 20 via the mesh spacer 29 as shown in FIG. The fins 19 extend from the rear end surface of the wound body 24. By providing the fin 19 at the same location in the fourth side portion 14 of each bag-like film 10, the fin 19 is positioned on the same radius from the axis of the wound body 24, and the fin 19 overlaps. The fin 19 forms a ring-shaped protrusion. The rear end of the cylindrical socket 25 is inserted into the ring-shaped protruding portion, and the socket 25 and the fin 19 are joined with an adhesive or the like. The socket 25 may be externally fitted to the fin 19. Further, a slit groove may be provided on the rear end surface of the wound body 24 along the fin 19 with a lathe, and the end portion of the socket 25 may be embedded in the groove.
[0043]
By joining the socket 25 and the fins 19 in this manner, the permeated water outflow region on the outer peripheral side of the rear end surface of the wound body 24 and the concentrated water outflow region on the inner peripheral side of the socket 25 are partitioned.
[0044]
When the bag-like film 10 is wound around the shaft 20, as shown in FIG. 5, a mesh spacer 29 is interposed between the bag-like films 10. By interposing these mesh spacers 29, a raw water flow path is configured.
[0045]
As shown in FIG. 7, a top ring 26 and an end ring 27 are respectively formed on the front edge and the rear edge of the wound body 24 by a synthetic resin mold or the like, and a brine seal 28 is provided around the outer periphery of the top ring 26.
[0046]
In the spiral membrane module configured as described above, as shown in FIG. 7, raw water flows from the front end face of the wound body 24 into the raw water flow path between the bag-like membranes 10, 10. This raw water flows through the raw water flow path in a direction substantially parallel to the axial center line of the wound body 24, and is taken out from the inner end face of the socket 25 at the rear end of the wound body 24. And while raw | natural water flows through a raw | natural water flow path in this way, water permeate | transmits in the bag-like film | membrane 10, and permeated water flows out from the outer peripheral side of the socket 25 among the rear-end surfaces of the winding body 24. FIG.
[0047]
In this spiral membrane module, the permeated water flows in the bag-like membrane 10 in the direction parallel to the axial center line of the wound body 24 and is taken out from the rear end surface, so that it is used in the conventional spiral membrane module. No water collection pipe is required. For this reason, there is no flow resistance when flowing from the bag-shaped membrane into the water collecting pipe, and the permeate flow resistance is significantly reduced.
[0048]
Note that the water collecting pipe is omitted, and the length of the bag-like membrane 10 in the winding direction can be increased correspondingly, and the membrane area can be increased. Even if the length of the bag-like membrane in the winding direction is increased, the permeate flow resistance does not increase, and the amount of permeate can be increased.
[0049]
In this membrane module, the outlet portion of the raw water channel is provided only inside the socket 25, and the outlet (the most downstream portion) of the raw water channel is narrowed. Also, the flow rate of the raw water (concentrated water) becomes sufficiently large, and it is possible to prevent the adhesion of dirt in the downstream area of the raw water flow path. The inner area and outer area of the socket 25 (the length in the direction of the side portion 14 of the adhesive 18) are preferably determined according to the water recovery rate of the spiral membrane module.
[0050]
Moreover, in this membrane module, the socket 25 is connected to the wound body 24 using the fins 19, and the connection strength between the socket 25 and the wound body 24 is high. The socket 25 separates the raw water inflow side and the concentrated water outflow side in a watertight manner.
[0051]
4 to 7, the permeate outflow portion is arranged on the outer peripheral side of the socket 25 and the concentrated water outflow portion is arranged inside the socket 25. You may comprise as a water outflow part and the outer peripheral side of the socket 25 may be used as a concentrated water outflow part.
[0052]
Such a method and apparatus of the present invention is suitable for coagulation filtration treatment of various irrigation water or wastewater containing organic or inorganic turbidity, and only a regular backwash is performed, and chemical cleaning is performed over a long period of time. Without performing the process, the membrane flux can be maintained stably, the amount of the flocculant used can be reduced, and the water recovery rate can be improved.
[0053]
The method shown in FIG. 1 is an example of an embodiment of the present invention, and the present invention is not limited to the illustrated method unless it exceeds the gist. For example, in FIG. 1, the entire amount of the membrane concentrated water is returned to the rapid stirring tank 2, but only a portion of the membrane concentrated water may be returned and the remaining portion may be discharged out of the system. Moreover, although the strainer 1 is provided in the front | former stage of the rapid stirring tank 2 in FIG. 1, when there are few comparatively big contaminants in raw | natural water, it is not necessarily required to provide a strainer. A wedge wire screen may be provided instead of the strainer.
[0054]
【Example】
Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.
[0055]
Example 1
The coagulation treatment was performed using the industrial water in Ibaraki Prefecture as raw water by the coagulation treatment apparatus shown in FIG. The specifications and processing conditions of each part were as follows.
[strainer]
Bucket type, 40 mesh [rapid stirring tank]
50L capacity, 200rpm flocculant with a stirrer (PAC) addition amount: 40mg / L
pH: 6-6.5
Residence time: 5 minutes [slow stirring tank]
100L capacity, 60rpm dwell time with stirrer: 15 minutes [Membrane Separator]
One 0.2 μm spiral type MF membrane module Permeate flow rate: 300 L / h Constant flow treatment Backwashing: Air backwashing for 0.5 minutes every 7.5 minutes of water flow. As a result, the operating pressure of the membrane separator changes over time. As shown in FIG. 3, the operating pressure of the membrane separator increased from 0.1 MPa to 0.27 MPa after 180 hours of water flow, and the rate of pressure increase was 0.0227 MPa / 24 h. The water recovery rate was 94%.
[0056]
Comparative Example 1
In Example 1, the membrane concentrated water was not returned to the rapid stirring tank, but the entire amount was discharged out of the system, and the same treatment was performed except that the amount of PAC added in the rapid stirring tank was 80 mg / L.
[0057]
As a result, the time-dependent change in the operating pressure of the membrane separator is as shown in FIG. 3, and the operating pressure of the membrane separator increases from 0.09 MPa to 0.38 MPa by passing water for 260 hours. The pressure was 0.0268 MPa / 24 h. The water recovery rate was 89%.
[0058]
Comparative Example 2
In Comparative Example 1, the treatment was performed in the same manner except that a strainer was not provided, a slow stirring tank was provided instead of the rapid stirring tank, and the slow stirring tank downstream of the rapid stirring tank was omitted.
[0059]
As a result, the time-dependent change in the operating pressure of the membrane separator is as shown in FIG. 3, and the operating pressure of the membrane separator increases from 0.075 MPa to 0.437 MPa by passing water for 139 hours. It was 0.0625 MPa / 24 h. The water recovery rate was 89%.
[0060]
Comparative Example 3
In Comparative Example 2, the treatment was performed in the same manner except that the amount of PAC added was 40 mg / L.
[0061]
As a result, the time-dependent change in the operating pressure of the membrane separator is as shown in FIG. 3, and the operating pressure of the membrane separator increases from 0.076 MPa to 0.438 MPa after 48 hours of water flow. It was 0.181 MPa / 24h. The water recovery rate was 89%.
[0062]
From the above results, it can be seen that according to the present invention, the flux of the membrane separator is stabilized, and the amount of the flocculant added is reduced and the water recovery rate is improved.
[0063]
【The invention's effect】
As described in detail above, according to the operation method and the coagulation treatment apparatus of the present invention, the coagulation agent is added to the raw water and the coagulation reaction is performed in the coagulation tank, and then the solid-liquid separation is performed in the membrane separation apparatus. It is possible to stabilize the flux by preventing clogging of the membrane, improve the water recovery rate, and reduce the amount of flocculant required for the flocculation treatment.
[0064]
In particular, according to the present invention, since the frequency of chemical cleaning can be reduced by stabilizing the flux of the membrane separation apparatus, the cost of chemicals for chemical cleaning is reduced, the efficiency of operating the apparatus is improved, and the life of the membrane is improved. It can be extended, and the raw water can be coagulated industrially with great advantage by reducing the processing cost and improving the processing efficiency.
[Brief description of the drawings]
FIG. 1 is a system diagram showing an embodiment of an operation method of an aggregating treatment apparatus and an aggregating treatment apparatus according to the present invention.
FIG. 2 is a system diagram showing a conventional method.
FIG. 3 is a graph showing the change over time in the operating pressure of the membrane separation apparatus in Example 1 and Comparative Examples 1 to 3.
4A is a perspective view of a bag-like membrane of a membrane module suitable for the present invention, FIG. 4B is a cross-sectional view taken along line BB in FIG. 4A, and FIG. It is sectional drawing which follows the CC line of a figure.
5 is a cross-sectional view showing a method for winding the bag-like film of FIG. 4;
6 is a perspective view showing an engagement relationship between a wound body and a socket in FIG. 4; FIG.
7 is a side view of the spiral membrane module according to FIG. 4;
[Explanation of symbols]
1 Strainer 2 Coagulation tank (rapid stirring tank)
3 Flock production tank (slow stirring tank)
4 Membrane Separator 10 Bag-shaped Membrane 11 First Side 12 Second Side 13 Third Side 14 Fourth Side 15 Channel Material 16, 17, 18 Adhesive 19 Fin 20 Shaft 24 Winding Body 25 Socket 29 Mesh spacer 30 Permeate outflow opening 31 Permeate outflow blocking closure

Claims (3)

A coagulation treatment step in which a flocculant is added to the raw water to cause a coagulation reaction in the coagulation tank, and the effluent from the coagulation tank is slowly stirred in the flock generation tank to generate flocs, and then solid-liquid separation is performed with a membrane separator And an operation method of the agglomeration processing apparatus having a backwashing step of backwashing the membrane separation device,
In the coagulation treatment step in which solid-liquid separation is performed by the membrane separation device, the water in the floc generating tank is taken out by a pump, and the discharge water of the pump is supplied to the membrane separation device to provide concentrated water and permeated water. And the concentrated water is returned to the coagulation tank without flowing into the floc generation tank ,
In the backwashing process for backwashing the membrane separation device, the total amount of water discharged from the pump is returned to the coagulation tank without flowing into the floc generating tank . how to drive. 2. The coagulation treatment step of performing solid-liquid separation according to claim 1, wherein a part of water discharged from the pump is supplied to the membrane separation device, and the remaining part is circulated to the coagulation tank. Operation method of the coagulation treatment apparatus. A flocculation tank for adding a flocculant to the raw water to perform a flocculation reaction;
A floc generating tank for generating flocs by gently stirring the effluent from the coagulation tank;
A flocculation treatment apparatus having a membrane separation device for separating outflow water from the flock production tank into concentrated water and permeate;
A feed path comprising a pump for feeding the effluent water from the flock production tank to the membrane separator;
A circulation path branched from the feed path downstream of the pump and communicating with the agglomeration tank;
A coagulation treatment apparatus comprising a return path for connecting the concentrated water outlet of the membrane separation apparatus and the coagulation tank.

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