Abstract:
A water-treatment membrane module with raw-water manifolds connected in common to both end portions of spiral membrane modules and allowing raw water to flow in or out of the spiral membrane modules, in which each of the manifolds comprises a box and cover which may be opened for inspection and access to a treated water manifold in fluid communication with the water collecting pipes.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a water-treatment membrane module unit and more particularly a membrane module unit with an improved connection structure between a spiral membrane module and a manifold. 
       BACKGROUND ART 
       [0002]    There has been a trial for removing microorganisms in ship ballast water through membrane treatment. Particularly in a huge ship such as a tanker, a capacity of a ballast tank is also huge, and a huge amount of ballast water needs to be treated in a short time if the ballast water is subjected to membrane treatment, and a large number of membranes need to be provided in the ship. 
         [0003]    Thus, the applicant of the present application proposed a water-treatment membrane module unit having a structure in which a plurality of spiral membrane modules are connected to a manifold constituting a flow passage for raw water (Patent Document 1). 
         [0004]    The spiral membrane module has a structure in which an outer periphery of a structural body formed by winding a plurality of envelop-shaped membranes around an outer periphery of a water collecting pipe is covered by an outer cylinder, and by connecting end portions of a plurality of spiral membrane modules to one manifold so that raw water can flow in/out, one water-treatment membrane module unit is constituted. 
         [0005]      FIG. 7  illustrates a sectional view of an essential part of this water-treatment membrane module unit. In the figure, reference numeral  100  denotes a spiral membrane module, reference numeral  200  denotes a first manifold connected to one of end portions of the spiral membrane module  100 , and reference numeral  300  denotes a second manifold connected to the other end portion of the spiral membrane module  100 . 
         [0006]    The spiral membrane module  100  has a water collecting pipe  103  having one end closed and only the other end open arranged at a center axis portion, and a plurality of membrane envelopes  102  are wound around an outer periphery of this water collecting pipe  103 . A structural body in which the plurality of membrane envelopes  102  are wound around the outer periphery of this water collecting pipe  103  is accommodated in an outer cylinder  101  so that a length direction of the water collecting pipe  103  accords with the length direction of the outer cylinder  101 . 
         [0007]    The first manifold  200  has a raw water chamber  201  which is common for the plurality of membrane modules  100  therein, and a raw-water inlet  202  through which raw water is introduced and a plurality of attaching opening portions  203  for connecting one end of the outer cylinder  101  of the spiral membrane module  100  are formed on a wall surface. 
         [0008]    The second manifold  300  has a cleaning drainage chamber (raw water concentrated liquid)  301  which is common for the plurality of spiral membrane modules  100  therein and a treated water chamber  302  which is partitioned from this cleaning drainage chamber  301  and is common for the plurality of spiral membrane modules  100 . The opening end of the water collecting pipe  103  of each of the spiral membrane modules  100  is connected to the treated water chamber  302 . On the wall surface, a treated water outlet  303  for discharging the treated water in the treated water chamber  302 , a drainage outlet  304  for discharging a drainage in the washing drainage chamber  301 , and a plurality of the attaching opening portions  305  for connecting the other end of the outer cylinder  101  of the spiral membrane module  100  are formed. 
         [0009]    The first manifold  200 , the second manifold  300 , and the outer cylinder  101  of the spiral membrane module  100  are fitted via a sealing member such as an O-ring or the like and connected by fixing by an adhesive or by extending a bolt (not shown) across the first manifold  200  and the second manifold  300 , for example, and by penetrating the opening end of the water collecting pipe  103  through the wall surface of the treated water chamber  302  of the second manifold  300 , the inside of the water collecting pipe  103  is made to communicate with the treated water chamber  302 . 
         [0010]    According to such water treatment membrane module unit, membrane treatment of a large quantity of the ballast water can be executed at the same time, which is extremely efficient, and various advantages such as space-saving and the like can be obtained. 
       CITATION LIST 
     Patent Document 
       [0000]    
       
         Patent Document 1: JP-A-2011-92824 
       
     
       SUMMARY OF THE INVENTION 
     Problem to be Solved by the Invention 
       [0012]    The inventor made a keen examination for further performance improvement of this water treatment membrane module unit and has found new problems as follows. 
         [0013]    First, since treated water from the spiral membrane module is collected by the water collecting pipe to one of end portions, an independent treated water chamber is provided only on one manifold of the manifolds connected to the both end portions of the spiral membrane module, respectively. As a result, a manifold structure is increased in size and complexity, and moreover, manifolds need to have structures different from each other. Particularly if the water treatment membrane module is to be mounted on a ship and to be used for treatment of the ballast water, in order to effectively use a limited space in the ship, a compact structure is a required condition. Thus, size reduction and simplification of each of the manifolds on the both end portions of the spiral membrane module and the manifold structure that can be used in common are in demand. 
         [0014]    Secondly, connection between an end portion side where the water collecting pipe of the spiral membrane module is open and the manifold needs to be in a watertight manner with respect to a bulkhead of the treated water chamber so that the end portion of the water collecting pipe communicates with the treated water chamber in the manifold in addition to watertight connection between the outer cylinder of the spiral membrane module and the manifold. That is because mixing of the raw water (raw water concentrated liquid) in the treated water needs to be avoided. However, since the water collecting pipe is connected so as to penetrate the bulkhead of the treated water chamber inside the manifold, a connected state between the end portion of the water collecting pipe and the bulkhead cannot be directly checked. Thus, easy checking of the connected state (sealed state) of the end portion of the water collecting pipe is in demand. 
         [0015]    Thirdly, since the end portion of the water collecting pipe is connected so as to penetrate the wall portion of the treated water chamber formed in the manifold, water-tightness between the end portion of the water collecting pipe and the bulkhead needs to be reliable. However, as described above, in combination with the fact that the connected state between the end portion of the water collecting pipe and the bulkhead cannot be directly checked, a reliable watertight structure cannot be made easily. Thus, connection of the end portion of the water collecting pipe with a reliable watertight structure is in demand. 
         [0016]    Thus, the present invention has an object to provide a water-treatment membrane module unit which can simplify the manifold structure to be connected in common to the both end portions of the plurality of spiral membrane modules, respectively, and can realize reliable watertight connection with the water collecting pipe of the spiral membrane module reliably and easily. 
         [0017]    Moreover, the other problems of the present invention will be made clear by the following description. 
       Means for Solving the Problems 
       [0018]    The above problems are solved by each of the following inventions. 
         [0019]    1. A water-treatment membrane module unit comprising: a spiral membrane module accommodating a water collecting pipe and a plurality of membrane envelopes wound around an outer periphery of the water collecting pipe in an outer cylinder and forming a raw water flow passage between the adjacent membrane envelopes and manifolds connected to both end portions of the plurality of spiral membrane modules in common and allowing raw water to flow in/out with respect to an outside, respectively, in which flowing in/out of the raw water is made possible between the raw water flow passage of the spiral membrane module and an inside of the manifolds, wherein each of the manifolds is constituted dividably by a first member including a side surface to which the spiral membrane module is connected and a second member including a side surface different from the side surface; and inside at least either one of the manifolds into which an end portion of the water collecting pipe is open, one treated water flow passage formed by a pipeline is provided, and the end portion of the water collecting pipe is connected to the treated water flow passage, respectively. 
         [0020]    2. The water-treatment membrane module unit according to 1, wherein the water collecting pipe has only one end portion open; and the water collecting pipe of each of all the spiral membrane modules is opened only to either one of the two manifolds, and the treated water flow passage is provided only inside the one manifold. 
         [0021]    3. The water-treatment membrane module unit according to 1, wherein the water collecting pipe has only one end portion open; and the water collecting pipe of each of all the spiral membrane modules branches and is opened to the two manifolds, respectively, and the treated water flow passage is provided inside the two manifolds, respectively. 
         [0022]    4. The water-treatment membrane module unit according to 1, wherein the water collecting pipe has both end portions open, respectively; and the water collecting pipe of each of all the spiral membrane modules is opened to the two manifolds, respectively, and the treated water flow passage is provided inside of the two manifolds, respectively. 
         [0023]    5. The water-treatment membrane module unit according to any one of 1 to 4, wherein the treated water flow passage is formed by connecting a plurality of pipeline members corresponding to each of the water collecting pipes of the spiral membrane module. 
       Effect of the Invention 
       [0024]    According to the present invention, the membrane module unit which can simplify the manifold structure connected in common to the both end portions of a plurality of membrane modules, respectively, and can realize reliable watertight connection with the water collecting pipe of the membrane module reliably and easily can be provided. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]      FIG. 1  is a perspective view of one water-treatment membrane module unit. 
           [0026]      FIG. 2  is a sectional view of a spiral membrane module. 
           [0027]      FIG. 3  is a sectional view of the water-treatment membrane module unit illustrated in  FIG. 1 . 
           [0028]      FIG. 4  is a sectional view illustrating another embodiment of the water-treatment membrane module unit. 
           [0029]      FIG. 5  is a sectional view illustrating still another embodiment of the water-treatment membrane module unit. 
           [0030]      FIG. 6  is a perspective view of the water-treatment membrane module unit illustrating another mode of a manifold. 
           [0031]      FIG. 7  is a sectional view of a prior-art water-treatment membrane unit. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0032]    Embodiments of the present invention will be described below. 
         [0033]      FIG. 1  is a perspective view of one water-treatment membrane module unit,  FIG. 2  is a sectional view of a spiral membrane module, and  FIG. 3  is a sectional view of the water-treatment membrane module unit illustrated in  FIG. 1 . 
         [0034]    The water-treatment membrane module unit (ballast treatment membrane module unit (hereinafter referred to simply as a unit))  1 A has a plurality of spiral membrane modules (hereinafter referred to simply as a membrane module)  2  juxtaposed in a row and a first manifold  3  and a second manifold  4  connected to both end portions of these membrane modules  2  and in common to these plurality of membrane modules  2 . 
         [0035]    The membrane module  2  has a water collecting pipe  21  which collects treated water, a large number of membrane envelopes  22  provided in a wound state around an outer periphery of this water collecting pipe  21 , and an outer cylinder  23  which covers an outer periphery of a structural body in which the membrane envelope  22  is wound around the outer periphery of this water collecting pipe  21 . The outer cylinder  23  is a cylindrical body having a cylindrical shape with both ends open and made of FRP and accommodates the above structural body therein so that a length direction of the water collecting pipe  21  accords with the length direction of the outer cylinder  23 . 
         [0036]    In each of the membrane envelopes  22 , a permeation side spacer  22   a  which maintains an extended state of the membrane envelope  22  and forms a space for the treated water having permeated an inside of the membrane envelope  22  is disposed, respectively. The inside of the membrane envelope  22  communicates with the inside of the water collecting pipe  21  so that the treated water having permeated the membrane envelope  22  can be transferred to the water collecting pipe  21 . The membrane envelopes  22  are radially attached to an outer peripheral surface of the water collecting pipe  21 , and since they are wound around the water collecting pipe  21  and wound in high density around the outer periphery of the water collecting pipe  21 , they present a substantially columnar shape having the water collecting pipe  21  as an axis as a whole. 
         [0037]    Between the adjacent membrane envelope  22 , a spacer  25  for preventing close contact between the membrane envelopes  22  with each other and narrowing of a membrane area and for forming a raw water flow passage  24  between the adjacent membrane envelopes  22  between the water collecting pipe  21  and the outer cylinder  23  is inserted. 
         [0038]    The water collecting pipe  21  has, as illustrated in  FIG. 3 , one end closed as a closed end portion  21   a  and the other end open for discharging the ballast treated water as an open end portion  21   b.    
         [0039]    It is only necessary that two or more membrane modules  2  are juxtaposed between the first manifold  3  and the second manifold  4 . The number is not limited but it is preferably within a range from 3 to 20, more preferably from 4 to 15 and still more preferably from 5 to 10. In this embodiment, 6 membrane modules  2  are juxtaposed in one row. 
         [0040]    The one first manifold  3  has a cuboid box shape, and one raw water chamber  31  in common to the plurality of membrane modules  2  is formed inside. A side surface  32   a  along the longitudinal direction of the first manifold  3  is a connecting surface with the plurality of membrane modules  2 , and connection opening portions  33  in the same number as that of the membrane modules  2  each protruding and formed having a cylindrical shape from the side surface  32   a  are juxtaposed. 
         [0041]    On one of end portions of each of the membrane modules  2 , the outer cylinder  23  is connected to this connection opening portion  33  in a watertight manner. As a result, the raw water flow passage  24  inside each of the membrane modules  2  communicates with the raw water chamber  31  in the first manifold  3  on one end portion side so that the raw water can flow in/out. 
         [0042]    On the one end portion in the longitudinal direction of the first manifold  3 , a supply port  34  for supplying the raw water to the raw water chamber  31  is formed, here, and by being connected to a supply pipe, not shown, the raw water can be supplied to the raw water chamber  31 . 
         [0043]    Moreover, the first manifold  3  is dividably composed of two members, that is, a first member  3   a  including the side surface  32   a  to which the membrane module  2  is connected and a second member  3   b  including a side surface  32   b  opposite to this side surface  32   a . The second member  3   b  includes the whole side surface  32   b  and is formed so as to extend along the longitudinal direction of the first manifold  3 . The supply port  34  is formed on the first member  3   a  side. 
         [0044]    The first member  3   a  and the second member  3   b  are joined while sandwiching a seal member, not shown, and are detachably integrated by an attaching bolt or the like, not shown, so as to constitute the box-shaped first manifold  3 . Thus, the first manifold  3  can open the raw water chamber  31  by removing the second member  3   b  as necessary, so that an internal state such as a connected state with the outer cylinder  23  of each of the membrane modules  2  and a sealed state, for example, can be directly checked. 
         [0045]    The other second manifold  4  also presents a cuboid box shape and has the same structure as that of the first manifold  3 . Inside it has one raw water chamber  41  formed in common to the plurality of the membrane modules  2 . One side surface  42   a  along the longitudinal direction of the second manifold  4  is a connecting surface with the plurality of membrane modules  2 , and connection opening portions  43  in the same number as that of the membrane modules  2  each protruding and formed having a cylindrical shape from the side surface  42   a  are juxtaposed. 
         [0046]    At the other end portion of each of the membrane modules  2 , the outer cylinder  23  is connected to this connection opening portion  43  in a watertight manner. As a result, the raw water flow passage  24  inside each of the membrane modules  2  communicates with the raw water chamber  41  in the second manifold  4  similarly to the first manifold  3  also on the other end portion side so that the raw water can flow in/out. 
         [0047]    On one end portion in the longitudinal direction of the second manifold  4 , a discharge port  44  for discharging the raw water (raw water concentrated liquid after treatment by the membrane module  2 ) in the raw water chamber  41  is formed, here, and by being connected to a discharge pipe, not shown, the raw water concentrated liquid in the raw water chamber  41  can be discharged. 
         [0048]    Moreover, the second manifold  4  is also dividably composed of two members, that is, a first member  4   a  including the side surface  42   a  to which the membrane module  2  is connected and a second member  4   b  including a side surface  42   b  opposite to this side surface  42   a . The second member  4   b  includes the whole side surface  42   b  and is formed so as to extend along the longitudinal direction of the second manifold  4 . The discharge port  44  is formed on the first member  4   a.    
         [0049]    The first member  4   a  and the second member  4   b  are joined by sandwiching a seal member, not shown, and are detachably integrated by an attaching bolt or the like, not shown, so as to constitute the box-shaped second manifold  4 . Thus, the second manifold  4  can open the raw water chamber  41  by removing the second member  4   b  as necessary, so that an internal state such as a connected state with the outer cylinder  23  of each of the membrane modules  2  and a sealed state and the connected state and the sealed state between the water collecting pipe  21  and a treated water flow passage  5  which will be described later, for example, can be directly checked. 
         [0050]    The open end portion  21   b  of the water collecting pipe  21  in each of the membrane modules  2  is faced in the raw water chamber  41  inside from the connection opening portion  43  of this second manifold  4 , respectively. In this raw water chamber  41 , the open end portion  21   b  of each of the water collecting pipes  21  is connected to one common treated water flow passage  5 , respectively. 
         [0051]    The treated water flow passage  5  is formed by connecting a plurality of pipelines  51  and  52 . The pipeline  51  is made of an L-shaped elbow pipe, in which one end is connected to the open end portion  21   b  of the water collecting pipe  21  in the membrane module  2  arranged on a side the closest to the end portion (upper end side in  FIG. 3 ), while the other end is open toward the longitudinal direction of the second manifold  4 . 
         [0052]    Moreover, the other pipelines  52  are all made of T-shaped pipes having the same shape and are connected to the water collecting pipes  21  of the membrane modules  2  other than the membrane module  2  connected to the above pipeline  51 . A connection port at a center of the pipeline  52  is connected to the open end portion  21   b  of the water collecting pipe  21  of the membrane module  2 , one of connection ports on both ends is connected to the other end of the above pipeline  51 , while the other is open toward the longitudinal direction of the second manifold  4  and is connected to the connection port of one of the both ends of the pipeline  52  to be connected to the water collecting pipe  21  of the adjacent membrane module  2 . 
         [0053]    The treated water flow passage  5  in the second manifold  4  constitutes a flow passage for collecting the treated water taken into the water collecting pipe  21  of each of the membrane modules  2  by connecting the one pipeline  51  to the five pipelines  52 . The other end portion in the longitudinal direction opposite to the discharge port  44  of the second manifold  4  has an opening portion  45  formed, and the treated water flow passage  5  is connected to a treated water discharge pipe  53  penetrating and connected to this opening portion  45  in a watertight manner. The opening portion  45  is formed on the first member  4   a  side of the second manifold  4 . 
         [0054]    In such a unit  1 A, connection between each of the water collecting pipes  21  and the treated water flow passage  5  can be made such that, after the outer cylinder  23  of each of the membrane modules  2  is connected to the connection opening portion  43  formed in the first member  4   a  of the second manifold  4  through the seal member, respectively, while the second member  4   b  is removed, the pipelines  51  and  52  are connected to the open end portion  21   b  of each of the water collecting pipes  21 , respectively. Since the connecting work of the pipelines  51  and  52  to each of the water collecting pipes  21  can be performed while directly and visually checking the state, the connected state and the sealed state can be easily checked, and reliable connection and sealing can be performed. After that, by joining the second member  4   b , the second manifold  4  having the treated water flow passage  5  inside is completed. 
         [0055]    Since each of the water collecting pipes  21  is connected by the pipelines  51  and  52  constituting the treated water flow passage  5  as above, watertight structure more reliable than the prior-art connection structure obtained only by penetration through the wall surface can be realized. 
         [0056]    Moreover, though the treated water flow passage  5  is formed only in the second manifold  4 , the first manifold  3  and the second manifold  4  can have the completely same structure, and thus, component control can be simplified, and cost reduction can be also realized. 
         [0057]    Moreover, since the treated water flow passage  5  is constituted by the pipelines  51  and  52  separately independent of the second manifold  4 , it is no longer necessary to form a chamber by partitioning the inside of the second manifold by a bulkhead as in the prior art, by which the size of the manifold can be made compact for that portion. 
         [0058]    An opening portion  35  is also formed at the same portion in the first manifold  3  corresponding to the opening portion  45  of the second manifold  4 , but since it is not necessary in this embodiment, it is closed by a closing member  36  in a watertight manner. 
         [0059]    In this unit  1 A, it may be so configured that the raw water is supplied to the second manifold  4 . In this case, the discharge port  44  functions as a supply port of the raw water, and the supply port  34  of the first manifold  3  functions as the discharge port of the raw water concentrated liquid. 
         [0060]      FIG. 4  illustrates another embodiment of the unit. The same reference numerals are given to the portions having the same configurations as in  FIG. 3 . 
         [0061]    In this unit  1 B, the water collecting pipe  21  of each of the membrane modules  2  has the open end portions  21   b  on the both end portions. The open end portion  21   b  of each of the water collecting pipes  21  is faced with the raw water chambers  31  and  41  in the first manifold  3  and the second manifold  4 , respectively, and connected to the treated water flow passage  5  having the same structure in the first manifold  3  and the second manifold  4 , respectively. Therefore, in this embodiment, the treated water discharge pipe  53  penetrates and is connected also to the opening portion  36  of the first manifold  3  in a watertight manner, and the unit  1 B as a whole has a bilaterally symmetric structure in the illustrated figure. 
         [0062]    In this unit  1 B, too, after the first member  3   a  of the first manifold  3  is connected to one end portion of each of the membrane modules  2  and the first member  4   a  of the second manifold  4  is connected to the other end portion, the treated water flow passage  5  composed of the pipelines  51  and  52 , respectively, is connected to the open end portion  21   b  of each of the water collecting pipes  21  and subsequently, it is only necessary to join the second members  3   b  and  4   b , respectively. 
         [0063]    According to this unit  1 B, in addition to the same effect as that of the unit  1 A, since the both first manifold  3  and the second manifold  4  have the treated water flow passage  5 , the treated water can be taken from both of them. Moreover, supply of the raw water and discharge of the raw water concentrated liquid can be performed both from the first manifold  3  and the second manifold  4 . Therefore, when a unit assembly is to be constituted by juxtaposing a large number of the units, the treated water discharge pipes  53  need to be juxtaposed so as to be aligned on the same side in the unit  1 A illustrated in  FIG. 3 , but in this unit  1 B, the treated water discharge pipe  53  is provided in both of the first manifold  3  and the second manifold  4  and thus, it is not necessary to pay attention so that they are directed in the same way when they are juxtaposed. 
         [0064]      FIG. 5  illustrates still another embodiment of the unit. The same reference numerals are given to the portions of same configuration as those in  FIG. 3 . 
         [0065]    In this unit  1 C, the water collecting pipe  21  of each of the membrane modules  2  has only one end portion as the open end portion  21   b  similarly to  FIG. 3 , and the open end portion  21   b  is made to branch to the first manifold  3  side and the second manifold  4  side for each of the membrane modules  2  and arranged. Here, the adjacent membrane modules  2  are arranged alternately on the first manifold  3  side and the second manifold  4  side. 
         [0066]    Therefore, in this unit  1 C, too, the treated water flow passage  5  connected to the open end portion  21   b  of the water collecting pipe  21  is provided in each of the first manifold  3  and the second manifold  4 , and the treated water discharge pipe  53  penetrates and is connected to the first manifold  3  and the second manifold  4 , respectively. 
         [0067]    The treated water flow passage  5  in the first manifold  3  is constituted by a pipeline  51   a  and a pipeline  52   a . In a point that the pipeline  51   a  is made of an L-shaped elbow pipe, and the pipeline  52   a  is made of a T-shaped pipe, they are equal to the pipelines  51  and  52  illustrated in  FIG. 3 , but in both of them, a length of one end is formed longer than the other. 
         [0068]    The treated water flow passage  5  in the second manifold  4  has the pipeline  51   a  and the pipeline  52   a  similar to the above, but only the pipeline  52  of a portion to be connected to the treated water discharge pipe  53  is formed to have the same structure as the pipeline  52  illustrated in  FIG. 3 . 
         [0069]    This unit  1 C can also connect each of the membrane modules  2  to the first manifold  3  and the second manifold  4  similarly to the unit  1 B. 
         [0070]    Moreover, in this unit  1 C, in addition to the same effect as that of the unit  1 A illustrated in  FIG. 3 , since the same treated water amount as in the unit  1 A can be divided into the treated water flow passage  5  on the first manifold  3  side and the treated water flow passage  5  on the second manifold  4  side and taken out, a flow rate of the treated water flowing through each of the treated water flow passages  5  can be made smaller than that in the unit  1 A. As a result, a diameter of the treated water flow passage  5  can be made thinner than that in the unit  1 A. Since the diameter of the treated water flow passage  5  is made thinner, capacities of the first manifold  3  and the second manifold  4  can be reduced, whereby the unit can be made more compact. 
         [0071]    Moreover, as compared with the unit  1 A, since the number of pipelines constituting the treated water flow passage  5  in one manifold becomes smaller, there is also an effect that a connecting work between the water collecting pipe  21  to the pipelines  51   a ,  52   a , and  52  in the manifold and a connecting work between the pipelines can be made more easily. 
         [0072]    These units  1 A,  1 B, and  1 C can treat a large amount of the raw water such as the ballast water and the like in a short time by constituting the unit assembly by combining a plurality of units with the same structure, that is, by combining the units  1 A with each other, the units  1 B with each other or the units  1 C with each other. 
         [0073]    In each of the assembled units  1 A,  1 B or  1 C, the supply pipe of the raw water and the discharge pipe of the raw water concentrated liquid may be individually connected to the supply port  34  and the discharge port  44 , respectively, or other than that, the unit assembly may be configured by connecting the supply port  34  and the discharge port  44  to the opening portions  35  and  45  of the other adjacent unit  1 A,  1 B or  1 C in a watertight manner so that the raw water chambers  31  and  41  communicate with each other among the plurality of units  1 A,  1 B or  1 C. In this case, for the treated water flow passage  5 , the T-shaped pipe may be used instead of the pipeline  51  made of the elbow pipe and connected to the treated water flow passage  5  in the other unit  1 A,  1 B or  1 C by a connecting pipeline, not shown, penetrating the opening portions  35  and  45 . 
         [0074]    In the units  1 A,  1 B, and  1 C described above, the supply port  34  ( 44 ) of the raw water and the discharge port  44  ( 34 ) of the raw water concentrated liquid are provided on the end portions in the longitudinal direction of the first manifold  3  and the second manifold  4 , but they may be provided at portions of the first members  3   a  and  4   a  of the first manifold  3  and the second manifold  4 , for example. 
         [0075]    Moreover, similarly, the treated water discharge pipe  53  may be also provided at the portions of the first members  3   a  and  4   a  of the first manifold  3  and the second manifold  4 . 
         [0076]    Furthermore, the first manifold  3  and the second manifold  4  described above are both configured capable of being divided into two members, that is, the first members  3   a  and  4   a  including the side surfaces  32   a  and  42   a  to which the membrane modules  2  are connected, and the second members  3   b  and  4   b  including the side surfaces  32   b  and  42   b  faced with these side surfaces  32   a  and  42   a , but the second members  3   b  and  4   b  may be any as long as they are formed by the side surfaces different from the side surfaces  32   a  and  42   a  to which the membrane modules are connected. Therefore, as illustrated in  FIG. 6 , the second members  3   b  and  4   b  may be formed so as to include the side surface adjacent to the side surfaces  32   a  and  42   a  to which the membrane module  2  is to be connected. 
         [0077]    By forming the first manifold  3  and the second manifold  4  so that each of the second members  3   b  and  4   b  is be arranged on the same side (the upper side in  FIG. 6 , for example) of the unit  1 A, a maintenance work can be performed for both the first manifold  3  and the second manifold  4  from the same direction, and workability can be improved. 
         [0078]      FIG. 6  illustrates the example using the unit  1 A, but the same applies to the other units  1 B and  1 C. 
       REFERENCE SIGNS LIST 
       [0000]    
       
         
           
               1  water-treatment membrane module unit (unit) 
               2  spiral membrane module (membrane module) 
               21  water collecting pipe 
               21   a  closed end portion 
               21   b  open end portion 
               22  membrane envelope 
               22   a  permeation side spacer 
               23  outer cylinder 
               24  raw water flow passage 
               25  spacer 
               3  first manifold 
               3   a  first member 
               3   b  second member 
               31  raw water chamber 
               32   a ,  32   b  side surface 
               33  connection opening portion 
               34  supply port 
               4  second manifold 
               4   a  first member 
               4   b  second member 
               41  raw water chamber 
               42   a ,  42   b  side surface 
               43  connection opening portion 
               44  supply port 
               45  opening portion 
               5  treated water flow passage 
               51 ,  52 ,  51   a ,  52   a  pipeline 
               53  treated water discharge pipe