JP2014151225A - Filtration membrane module, and method for inspecting the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a filtration membrane module having such a structure that a broken membrane can be specified quickly by a simple operation while preventing quality deterioration of permeated water due to always keeping a member, which is used for evaluating the quality of the permeated water, on the water surface, and to provide a method for inspecting the filtration membrane module by using the same.SOLUTION: A filtration membrane module 2 has: a plurality of filtration membrane elements 1; a water collection pipe 4 for collecting the permeated water to be obtained from the plurality of filtration membrane elements 1; a plurality of water collection tubes 3 each of which is communicated with the plurality of respective filtration membrane elements 1 and the water collection pipe 4; and an air diffusion unit 6 for supplying air to the surfaces of the plurality of filtration membrane elements 1. The filtration membrane module 2 is immersed/installed in a treatment tank 7, in which the liquid to be treated and activated sludge are stored, during the filtration operation. At least a part of the water collection tube 3 can be taken up to the water surface without interrupting the filtration operation.

Description

  The present invention relates to a filtration membrane module for solid-liquid separation of a microorganism-containing liquid containing a liquid to be treated and activated sludge using a membrane, and a method for inspecting the operating state thereof.

  The membrane separation method is a technology that is widely used while expanding its application field because it has features such as energy saving, space saving, labor saving, and product quality improvement. Examples of membrane separation methods include reverse osmosis, ultrafiltration, and microfiltration. Further, the form of the filtration membrane includes a hollow fiber membrane, a flat membrane, a tubular membrane, and the like, which are properly used according to the properties and characteristics of each separation object. Recently, from the viewpoint of environmental conservation, research is being conducted to apply membrane separation technology to wastewater treatment.

  In wastewater treatment, solid-liquid separation by precipitation is often performed, but if membrane separation technology can be implemented as an alternative, not only high-quality treated water can be obtained, but a large sedimentation basin can be omitted or reduced. And the space merit is very large. In wastewater treatment, an activated sludge treatment process that separates flocked sludge and treated water after decomposing organic matter in the wastewater by microorganisms called activated sludge is widely used. When activated sludge is concentrated to increase the treatment efficiency, the decomposition process proceeds, but sludge sedimentation may occur in the subsequent sedimentation basin, and management work to prevent deterioration of water quality is complicated. . However, if membrane separation technology is adopted as an alternative to precipitation separation, problems such as deterioration of water quality and space securing can be solved, and membrane separation technology has attracted attention.

  From the above points, immerse a filtration membrane module in which a plurality of filtration membrane elements are connected with a collection tube in a water tank containing activated sludge, and suck the permeate side of the module with a pump or siphon, etc. Research on a submerged filtration membrane module that obtains permeated water using the difference in water level has been conducted. In activated sludge treatment, aeration is usually performed to keep aerobic microorganisms. This immersion type uses a swirl flow formed in the water tank by aeration to separate the solid and liquid while scraping the membrane surface. Can be operated at a very low cost.

  At that time, the problem is that if the membrane is damaged for some reason and the permeated water quality deteriorates, the damaged membrane is identified, and the immersed membrane module is taken out of the water tank or the water tank. Because it is necessary to discharge the activated sludge inside, there is a problem that it takes a lot of time and labor to inspect and identify all the membranes in the module. As means for solving such problems, there are a liquid flow path inside, a plurality of liquid flow inlets for introducing liquid into the liquid flow path from the outside, and a liquid flow outlet for guiding liquid from the inside of the liquid flow path to the outside. A water collecting apparatus having a casing formed with a water collecting apparatus, wherein a peep window capable of observing the inside of the liquid channel from the outside is formed in the casing. There has been proposed a method in which an individual element in a filtration membrane module is connected to a water collecting device, and the state of permeate is visually observed from a viewing window to identify a damaged membrane (Patent Document 1).

JP 2001-187381

  However, although the method of patent document 1 can identify a damaged membrane without changing the state of a water tank or a filtration membrane module, it is always a part of the water collecting device casing and the water collecting tube having such a complicated shape. Since the water is provided on the surface of the water, it is inevitable that the quality of the permeated water deteriorates, such as the retention of permeated water in the water collecting device and the irradiation of sunlight, and the propagation of microorganisms and algae in the permeated water caused by them. Since a large number of elements are connected to a single water collecting device, the flow of permeated water in the water collecting device interferes with each other, making it difficult to identify elements that emit permeated water containing turbidity. There was a point.

  The present invention is a filtration having a structure capable of quickly identifying a damaged membrane by a simple operation while preventing deterioration of the permeated water quality by always providing a member for confirming the quality of the permeated water on the water surface. It aims at providing the inspection method of a membrane module and a filtration membrane module using the same.

  The present invention for solving the above-mentioned problems has the following features.

  (1) A plurality of filtration membrane elements, a water collection tube for collecting permeated water obtained from the plurality of filtration membrane elements, and a plurality of water collection tubes communicating with each of the plurality of filtration membrane elements and the water collection tube A filtration membrane module at the bottom of the plurality of filtration membrane elements and having an air diffuser for supplying air to the surface of the filtration membrane element, the filtration membrane module being treated during filtration operation A filtration membrane module, wherein the filtration membrane module is immersed in a treatment tank storing liquid and activated sludge, and at least a part of the water collecting tube can be pulled up on the water surface without interrupting the filtration operation. .

  (2) The filtration membrane module according to (1), wherein the water collection tube has a structure that can expand and contract in a flow direction of permeated water.

  (3) When performing the filtration operation with the filtration membrane element in the treatment tank storing the liquid to be treated and the activated sludge using the filtration membrane module according to (1) or (2), the water collecting tube is used. A method for inspecting a filtration membrane module, wherein the presence or absence of an abnormality in the filtration membrane element is confirmed by pulling it up onto the water surface in the treatment tank and directly observing it.

  According to the present invention, since the state of the permeated water in each water collecting tube can be confirmed by a simple operation, the damaged membrane can be quickly and reliably specified when an abnormality occurs. Moreover, since the water collection tube is immersed in the activated sludge except when the state of the permeated water is confirmed and does not have the permeated water retention portion, it is possible to prevent the quality of the permeated water from deteriorating.

It is a schematic front view which shows one embodiment of the filtration membrane module used by this invention. It is a schematic front view which shows another embodiment of the filtration membrane module used by this invention. It is the schematic which shows an example of the water collection pipe | tube used by this invention. It is the schematic which shows the water collecting apparatus used in the comparative example 1.

  Hereinafter, the filtration membrane module according to the present invention will be described based on the embodiment shown in FIG.

  A filtration membrane module 2 shown in FIG. 1 has a plurality of filtration membrane elements 1 installed to obtain a permeate by subjecting the liquid to be treated to membrane filtration, and a water collecting pipe for collecting the permeate obtained from the filtration membrane element 1. 4, a plurality of water collection tubes 3 communicating with each of the plurality of filtration membrane elements 1 and the water collection pipe 4, and a lower portion of the plurality of filtration membrane elements 1, and supplying air to the surface of the filtration membrane element 1 In order to take out permeated water out of the system, a diffuser 6, a treatment tank 7 for immersing the filtration membrane module 2 in the liquid to be treated, and a water collecting pipe 4 provided on the downstream side of the filtration membrane module 2. The water supply pipe 5 is provided.

  And in this invention, the water collection tube 3 is normally immersed in the to-be-processed liquid by the above structures, and the water collection tube 3 is the water surface of a to-be-processed liquid in the part or all in the orthogonal | vertical direction. The present invention can be lifted up, and the present invention will be described below based on this embodiment.

  In the present invention, the filtration membrane module 2 is configured as described above, and when an abnormality such as an increase in turbidity is found in the permeated water from the filtration membrane module 2 during the filtration operation, the filtration operation is continued. The water collecting tube 3 and the water collecting tube 4 are pulled up so that at least a part of the water collecting tube 3 comes out on the water surface of the liquid to be treated, and each filtration membrane passes through the inside of the water collecting tube 3 pulled up on the water surface. The permeated water from the element 1 can be observed, and the damaged filtration membrane element 1 can be identified and measures such as sealing can be taken.

  At this time, as shown in FIG. 1, the water collection pipe 4 is structured to be movable in the vertical direction, and may be pulled up so as to come out on the water surface of the liquid to be treated together with the water collection tube 3, or as shown in FIG. The water collecting tube 4 may be fixed and immersed in the liquid to be treated, and only the water collecting tube 3 may be exposed on the surface of the liquid to be treated.

  By adopting such an apparatus configuration and procedure, it is possible to accurately and quickly determine which filtration membrane element 1 has an abnormality when necessary, which is very important for identifying a conventional damaged filtration membrane element 1. It can solve the problem of taking a lot of time and labor.

  Moreover, since the normal water collection tube 3 and the water collection tube 4 are immersed in the to-be-processed liquid containing activated sludge, direct sunlight is interrupted and the algae reproduction by photosynthesis and the deterioration of permeated water quality by it are prevented. Can do.

  Furthermore, since the water collection tube 3 and the water collection tube 4 have a simple configuration of tubes and tubes and do not have a portion where the permeated water stays, the permeated water stays rotted, microorganisms propagate and the quality of the permeated water is thereby prevented. be able to.

  The water collecting tube 3 is not particularly limited as long as the permeated water from the filtration membrane element 1 can be sent to the water collecting tube 4, but from the viewpoint of observing the permeated water state in the tube, the water collecting tube 3 is transparent or translucent chloride. It is preferably made of a resin such as vinyl or polyurethane. In addition, as described above, in order to move up and down in the treatment tank 7, it is necessary to have a sufficient length to pull it up on the water surface. It is more preferable to have a structure that can be expanded and contracted in the flow direction of the permeated water, such as application of a resin having elasticity in the length direction of the tube. In particular, the bellows structure is more preferable because an excessive physical load is not applied to the connection portion with the filtration membrane element 1 at the time of expansion and contraction, and thus the expansion and contraction can be performed without causing problems such as breakage or dropout of the connection portion.

  The water collecting pipe 4 is not particularly limited as long as it has a connection port with the water collecting tube 3 and the water supply pipe 5, and a pipe made of resin such as polyethylene, vinyl chloride or polypropylene, or a steel pipe such as stainless steel is necessary. From the viewpoint of preventing the permeated water from staying, the circular pipe 8 is provided with a necessary number of water supply pipe connection ports 9 and water collection tube connection ports 10 as shown in FIG. Is preferred.

  The filtration membrane disposed on the filtration membrane element 1 is not particularly limited as long as the permeated water can be separated from the liquid to be treated, and those made of a resin such as polyethylene, polyvinylidene fluoride, and polysulfone are preferably used.

  The water supply pipe 5 is not particularly limited as long as the permeated water can be guided to a predetermined position. A pipe made of resin such as polyethylene, vinyl chloride, polypropylene, or a steel pipe such as stainless steel is used in combination as necessary. .

  The air diffuser 6 is not particularly limited as long as air for cleaning the surface of the filtration membrane element 1 can be appropriately sent to each filtration membrane element 1, and is made of a resin such as polyethylene, vinyl chloride, or polypropylene. A steel tube made of rubber such as EPDM or stainless steel or a stainless steel tube is used in combination as necessary.

  The treatment tank 7 is not particularly limited as long as it can store the liquid to be treated and the filtration membrane module 2 can be immersed in the liquid to be treated, and a concrete tank, a fiber reinforced plastic tank, or the like is preferably used. Moreover, the inside of the processing tank 7 may be divided into a plurality of parts, and a part of the plurality of divided tanks is used as a tank for immersing the filtration membrane element, and the other is used as a denitrification tank. May be circulated between the tanks divided from each other.

  Examples of the liquid to be treated include domestic wastewater such as sewage and human waste, and industrial wastewater discharged from various factories and manufacturing processes, but are not limited thereto. Activated sludge is an aggregate of microorganisms that propagate by aeration and / or stirring in their wastewater and have the ability to purify wastewater.

Example 1
A filtration membrane module 2 (filtration membrane element 1 × 100) including 1 × 1 filtration membrane element in which three holes with a diameter of 2 mm are previously formed in the membrane surface so that the filtration membrane element 1 has a simulated defect. Sheet, water collecting tube 3 × 100, water collecting tube 4 × 1) are installed in a treatment tank 7 having a length of 2 m × width of 2.5 m × water depth of 3 m, and one of the water collecting tubes 4 is connected to the water supply pipe 5 Then, the filtration operation was started in a state where the activated sludge was filled in the tank and the filtration membrane module was immersed therein. At that time, the water collecting pipe 4 having a shape shown in FIG.

  Immediately after the start of operation, activated sludge-like suspended solids were found in the permeated water exiting from the end of the water supply pipe 5, so that all of the water collection pipe 4 and a part of the water collection tube 3 were on the water surface while the operation was continued. The water collection pipe 4 was pulled up with a chain block until it came out.

  The outside of the water collection tube 4 and the water collection tube 3 was washed with running water, and each water collection tube 3 was observed. As a result, turbidity was observed in the permeated water flowing through the inside of the single water collection tube 3. Closed. Five minutes later, when the permeate flowing out from the end of the water supply pipe 5 was confirmed, no suspended matter or turbidity was observed, and it was shown that the damaged filtration membrane element 1 could be accurately identified by observation of the water collection tube 3. It was done. It took 15 minutes to confirm the suspended membrane in the permeated water, identify and close the damaged filter membrane element 1 and confirm the good state of the permeated water.

  Thereafter, the operation was continued as it was for one month, and the permeated water coming out from the end of the water supply pipe 5 was confirmed again, but no suspended matter or turbidity was observed.

(Comparative Example 1)
In place of the water collecting pipe 4, the water collecting device 4 'shown in FIG. 4 was fixed on the water surface, and the filtration operation was started under the same conditions as in Example 1 except for the above. Here, the water collecting device 4 ′ is a device in which a required number of water supply pipe connection ports 9 ′ and water collecting tube connection ports 10 ′ are provided in a rectangular parallelepiped box 8 ′, and a peep window 11 that can be opened and closed is provided at the top of the box. The permeated water flowing into the box 8 'from the observation window 11 can be observed.

  Immediately after the start of operation, activated sludge-like suspended matter was found in the permeate flowing out from the end of the water supply pipe 5, so that the observation window 11 of the water collecting device 4 'was opened and the water collecting tubes were kept in operation. When the permeated water from 3 was observed, turbidity was observed in a part of the water collecting device 4 ′, but it was not possible to determine from which water collecting tube 3 the permeated water flowed. Therefore, the water collecting tubes 3 in the vicinity where turbidity is observed are alternately closed with a pinch cock three times each, and the operation of confirming the permeate flowing out from the end of the water supply pipe 5 after 5 minutes is repeated three times. The membrane element 1 damaged from the permeated water quality was identified and closed. It took 23 minutes to check the suspended filter membrane element 1 after confirming suspended solids in the permeated water, and to confirm the good state of the permeated water.

  Thereafter, the operation was continued for one month, and when the permeated water exiting from the ends of the water collecting device 4 ′ and the water supply pipe 5 was confirmed again, the portion on the water surface of the water collecting tube 3 and the water collecting device 4 'Green algae breeding was observed at the corner of the inside, and green suspended solids that were thought to be derived from green algae were also observed in the permeated water.

(Comparative Example 2)
The filtration operation was started under the same apparatus and conditions as in Example 1 except that the water collection pipe 4 was fixed in the vicinity of the filtration membrane element 1 and could not be put out on the water surface.

Immediately after the start of operation, activated sludge-like suspended solids were found in the permeate flowing out from the end of the water supply pipe 5, so the filtration operation was stopped, and the activated sludge in the treatment tank 7 was removed from the water collection pipe 4 and the water collection tube 3. withdrawn about 5m ³ to come out on the surface of the water, it was stored in the temporary tank (not shown). After that, the outside of the water collecting pipe 4 and the water collecting tube 3 was washed with running water, and each water collecting tube 3 was observed. As a result, the activated sludge-like substance adhered to the inner wall with one tube, and the tubes were pinched. Closed with a cock. Thereafter, the activated sludge in the temporary tank was returned to the treatment tank 7, the filtration operation was resumed, and the permeated water exiting from the end of the water supply pipe 5 was confirmed after 5 minutes. It took 65 minutes to confirm the suspended membrane elements in the permeated water, identify and close the damaged membrane element, and confirm the good state of the permeated water.

  Thereafter, the operation was continued as it was for one month, and the permeated water coming out from the end of the water supply pipe 5 was confirmed again, but no suspended matter or turbidity was observed.

  INDUSTRIAL APPLICABILITY The filtration membrane module and the inspection method of the present invention can be used easily as a filtration membrane module capable of stable operation and an inspection method thereof that can easily and quickly cope with a membrane breakage in the field of sewage treatment. .

1: Filtration membrane element 2: Filtration membrane module 3: Water collection tube 4: Water collection tube 4 ': Water collection device 5: Water supply pipe 6: Air diffuser 7: Treatment tank 8: Circular pipe 8': Boxes 9, 9 ' : Water supply pipe connection port 10, 10 ': Water collection tube connection port 11: Peep window

Claims (3)

  A plurality of filtration membrane elements, a water collection tube for collecting permeated water obtained from the plurality of filtration membrane elements, a plurality of water collection tubes communicating with each of the plurality of filtration membrane elements and the water collection tube, and a plurality of A filtration membrane module having an air diffuser for supplying air to the surface of the filtration membrane element, wherein the filtration membrane module is used for the liquid to be treated and the activity during the filtration operation. A filtration membrane module, wherein the filtration membrane module is immersed in a treatment tank in which sludge is stored, and at least a part of the water collection tube can be pulled up on a water surface without interrupting a filtration operation.   The filtration membrane module according to claim 1, wherein the water collection tube has a structure that can expand and contract in a flow direction of permeated water.   When performing the filtration operation by the filtration membrane element in the treatment tank storing the liquid to be treated and activated sludge using the filtration membrane module according to claim 1 or 2, the water collection tube is connected to the water surface in the treatment tank. A method for inspecting a filtration membrane module that confirms the presence or absence of an abnormality in the filtration membrane element by pulling it up and directly observing it.

Images