JP2004089766A - Ascending flow filtering method for suspension water and apparatus therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new technique capable of rapidly filtering suspended particles in raw water of every kind such as sewage with a simple and compact apparatus by reducing the rise in head loss. <P>SOLUTION: In an ascending flow filtering method for suspension water, a suspension water is allowed to flow in the lower part of a filter column, wherein a large number of string-like members or fiber bundle string-like members with synthetic fiber yarn fringes (tufts) are suspended in such a state that the upper ends of them are fixed by a fixing member, and passed as ascending flows to perform filtering while making filtered water flow out from the upper part of the filter column. An ascending flow filtering apparatus for suspended water is constituted by suspending the string-like members or fiber bundle string-like members with a large number of the synthetic fiber yarn fringes (tufts) in the filter column having a suspended water inflow part and a filtered treated water outflow part respectively provided to the lower and upper parts thereof. The lower ends of the string-like members are preferably set to free ends to be suspended. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method and an apparatus for high-speed filtration and separation of suspended water containing suspended particles such as sewage and industrial wastewater, and a technique capable of filtering and removing suspended particles in suspended water (hereinafter also referred to as “raw water”) at a high speed. About. INDUSTRIAL APPLICABILITY The present invention is an innovative technology which is particularly suitable as a high-speed solid-liquid separation technique for rainwater overflow (hereinafter abbreviated as CSO) of a combined sewer containing organic suspended particles or sewage flowing into a sewage treatment facility. It is.
[0002]
[Prior art]
Recently, the pollution load of public water bodies due to rainfall overflow (CSO) in a combined sewer has become a major problem.
In addition, the sewage flowing into the sewage treatment facility is first subjected to sedimentation and separation in the sedimentation basin and then to activated sludge treatment. Examples of this are prevalent in Scandinavia. However, this method has the disadvantages that a large amount of sludge is generated, the coagulation and sedimentation rate is low, and a large sedimentation tank is required. Therefore, a new technology that can separate CSO and sewage into solid and liquid with as small a facility as possible is expected.
[0003]
Conventionally, as a technique for filtering and removing SS from a suspension, deep bed filtration using granular materials such as sand and anthracite as a filter medium is known. However, when an attempt is made to remove organic SS such as sewage. Clogging was severe and not practical.
Filtration methods using various granular solids (eg, granular plastic) other than anthracite and sand as filter media are also being studied. However, if the filter media size is increased to reduce clogging, the SS removal rate will deteriorate. The contradiction point has arisen. In particular, since organic SS contained in sewage or the like has a strong adhesive force, a technology that can satisfy the conflicting requirements of high sewage removal rate and small clogging for such sewage has not been put to practical use.
[0004]
[Problems to be solved by the invention]
The present invention has been made in view of such circumstances, and provides a new technology that enables high-speed filtration of suspended particles in various raw waters such as sewage by a simple and compact device with a small increase in head loss. That is the task.
[0005]
[Means for Solving the Problems]
The present invention has solved the above problems by the following means.
(1) A string-like member or a fiber bundle-like member with a synthetic fiber yarn fringe (bristles) is fixed inside the tower, and suspended water is allowed to flow from the lower part of the filtration tower in which the upper end is fixed with a fixing member and a large number is hung. A method of filtering the suspension water by flowing the water as an upward flow and discharging the filtered water from above.
(2) A string member or a fiber bundle string member with a synthetic fiber yarn fringe (bristles) is provided inside a filtration tower having a suspension water inflow portion at a lower portion and a filtered water outflow portion at an upper portion. An upflow filter for suspended water, wherein the suspended water is fixed by a fixing member and is suspended in a large number.
(3) The upward-flow filtration device according to (2), wherein the lower end of the string-shaped member is suspended as a free end.
[0006]
Preferred embodiments of the present invention include the following.
(4) The upward flow filtration device according to (2) or (3), wherein the synthetic fiber is an acrylic fiber.
(5) The fringe-like string-like member is characterized in that fringe-like acrylic fibers having a thickness of 2 mm and a length of 30 mm are attached in a horizontal direction at a pitch of 20 mm in a height direction of a string having a length of 1 m. The upward flow filtration device according to any one of (2) to (4) above.
(6) In any one of the above (2) to (5), wherein the cord-like member is suspended and filled in the filtration tower so that the porosity of the packed bed is 90% or more and the average pore size is 15 mm or more. An upflow filter as described.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a configuration diagram showing one embodiment of the high-speed filtration device of the present invention.
A filtration device (filtration tower) 3 provided with an inflow portion of raw water 1 at a lower portion and an outflow portion of filtered water 2 at an upper portion has a large number of synthetic fiber thread fringes 14 as shown in FIG. The string-shaped member 16 or the string-shaped member 16 of the bundled long fiber bundle 15 as shown in FIG. In this case, the porosity of the filling layer can be easily increased to 90% or more, and the size of the porosity can be made larger than that of the method of filling the granular filter material, so that the clogging is hardly caused.
[0008]
The filler 4 is preferably provided by suspending and fixing the upper ends of a number of long fiber bundles to a fixing member 5 such as a wire mesh or a slit plate. In addition, it is preferable that the lower end of the string-shaped member is suspended as a free end.
In FIG. 1, 7 is a water surface, and 8 is a light weight.
[0009]
The string constituting the string member 14 or the fiber bundle member 16 with the synthetic fiber fringe of the present invention is formed by combining a thread, a cloth, or the like, and twisting, knitting, weaving, bundling, kneading, or any other long and narrow material. It may be in the form of spun yarn or processed yarn, which is typically an aggregate of monofilaments or long fibers, or a multifilament which is an aggregate of long fibers, and the raw material fiber is polyester or polyolefin. And synthetic fibers such as polyamide, polyacrylonitrile, polysulfone, polyamideimide, polyimide, polyphenylene sulfide, and polyvinylidene fluoride. These fibers can be used alone or in combination or as a resin-impregnated yarn.
[0010]
The fineness of the single yarn constituting the string-shaped member is 10 to 5000 denier, preferably 20 to 2000 denier, and more preferably 30 to 1000 denier. If it is less than this, sufficient strength as a filter medium is lacking, and if it exceeds this, the rigidity increases, and the performance as a filter medium decreases.
Further, the length of the cord-like member is preferably from 1 to 2 m, more preferably from 1.0 to 1.5 m. If it is not within this range, the size of the filter element becomes large, or the flow in the filter becomes non-uniform, so that the filtration performance is reduced.
[0011]
The cross-sectional shape of the string-shaped member may be any of a circle, an ellipse, a rectangle, and a triangle. Further, the cross-sectional shape of the string-shaped member may be the same or different in the longitudinal direction. In the present invention, the diameter of the string-shaped member is not particularly limited, but is preferably 2 mm to 10 mm, and more preferably 2 mm to 5 mm.
Further, in addition to the string-like member 16 of the bundled long fiber bundle 15 shown in FIG. 2, a fiber filter 18 having the structure shown in FIG. 4 can be used as the fiber filter made of the string-like member.
[0012]
The fiber filter medium 18 made of a string-like member is composed of a core string 18a and a number of loop threads 18b formed in a loop around the outer peripheral surface of the core string 18a. The core string 18a has, as a core material, a filament bundle 18c formed by bundling a plurality of filaments made of synthetic resin at a central portion.
The outer peripheral surface of the filament bundle 18c is surrounded by a tubular net 18e formed by weaving the power yarn 18d. The core string 18a is formed by spirally weaving the loop yarn 18b in one or more of the power yarns 18d of the annular net 18e along the power yarn 18d. Therefore, the fiber filter medium 18 has a state in which a large number of minute gaps capable of holding foreign matter in the water to be treated are formed between the dense loop yarns 18b, thereby making the filter medium an excellent filter material. .
At both ends of the fiber filter 18, the loop yarn 18 b is squeezed, and an adhesive tape 18 f made of a synthetic resin is wound around the outer periphery of the loop 18 b, thereby preventing the yarn from fraying at the end of the fiber filter 18. I have to.
[0013]
As described above, the shape of the string-shaped member as a fiber filter material may be a string-shaped, rope-shaped, string-rope-combined body, or a sump-shaped, as appropriate, depending on other uses, such as a filtration tower for water purification and a filtration tank. It can be used as a cord bundle, a net-like material, or the like.
Also, as shown in FIG. 1, the method of attaching the lightweight weights 8 to the individual cord-shaped fillers 4 is time-consuming, which may increase the material cost. In such a case, the mounting member 17 can be used as a common weight as shown in FIG.
And, the above-mentioned cord-like filler is suspended in a filtration tower (tank) in a large number at a porosity of 90 to 97%, preferably 95%, and a pore size of 10 to 20 mm, preferably 15 mm on average. , In terms of filtration performance.
[0014]
In addition, among the synthetic fibers described above, especially acrylic fibers, unlike synthetic fibers produced by a melt spinning method such as other polyester fibers and polyamide fibers, most of them are produced by a wet spinning method. There are countless minute irregularities on the surface, the specific surface area is larger than that of fibers produced by the melt spinning method and the surface is smooth, and the capture rate of SS and the like is improved. Moreover, since high bulky yarn which is not found in other synthetic fibers can be manufactured, it is particularly advantageous for manufacturing the fiber bundle-shaped member shown in FIG.
In addition, acrylic fiber is also excellent in light resistance, so it can be said that it is a very excellent material as a filter fiber used outdoors.
[0015]
For such a packed layer having a large porosity, raw water 1 such as sewage or raw water 1 to which a flocculant (a polymer flocculant alone or a combination of an inorganic flocculant and a polymer flocculant) has been added, It is circulated in a stream, and the suspended particles in the raw water 1 are captured in the gaps of the string-shaped member 4 and removed by filtration. The filtered water 2 flows out from the upper part of the device 3. The thickness of the filling layer 5 composed of the string-shaped member 4 is preferably about 1 to 2 m.
If the operation continues, the SS trapping capacity of the string-like member 4 reaches the limit and the SS of the treated water 2 rapidly increases or the filtration resistance reaches a predetermined value. Wash.
[0016]
Filter medium washing is performed, for example, as follows. That is, air is diffused from the air diffuser 9 for several minutes, and the suspended string-like member 4 is strongly disturbed to separate the turbidity attached to the levitating particles. When the lower end of the string-shaped member 4 is hung down as a free end, the string-shaped member 4 as a filler vibrates to the left and right violently by aeration, so that the sludge peeling effect is further improved.
Then, the water in the tank is rapidly discharged from the drainage pipe as the washing drainage 12. As a result, the suspended matter trapped in the string-shaped member 4 is discharged, and the packed layer is cleaned. In addition, 11 is a blower.
Since the filtration layer is easily washed by the mechanism as described above, the raw water 1 is supplied again and filtration is started.
[0017]
【Example】
Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to such Examples.
[0018]
Example 1, Filtration test of combined sewer sewerage storm water overflow A string-shaped filler (a 20 mm pitch in the height direction of a 1 m long string, a 30 mm long fringe) was placed in a square cylindrical container having a diameter of 30 cm. A packed layer (filled layer porosity 95%, void size; average of 15 mm) in which a number of acrylic fibers (thickness of twisted yarn of 2 mm in thickness) attached horizontally (appearance is shown in FIG. 1) are suspended. ) Was used to perform a sewage filtration test.
[0019]
As a preliminary test, water was passed through the sewage (130 mg / L SS) at an ultra-high speed of 1440 m / d in the upward flow. As a result, the filtered water SS was 33 to 42 mg / liter over 2 hours after the start of operation. However, after 2 hours and 10 minutes, the filtered water SS deteriorated to 85 mg / liter.
Then, after operating for 2 hours, the supply of raw water was stopped, and the operation was performed in a cycle of performing washing.
[0020]
Washing was performed by aeration for 3 minutes and draining the entire amount of water in the apparatus in 1 minute. As a result, even if the operation was continued for 1 month, the filtered water SS was 157 mg / liter of the raw water average and the filtered water SS It was 38 mg / liter, and good SS removal was performed. After one month, the state of the filler after cleaning was clean, unchanged from the initial state of the filling, except that the fringe portion was blackened.
[0021]
【The invention's effect】
According to the present invention, the application of the granular filter medium is abolished, a packed layer is formed by suspending a number of string-shaped members, and as a result of using this as a filtration layer, suspended water such as sewage is less clogged. Can be filtered at high speed.
Further, since the SS of the raw water can be filtered without necessarily adding the coagulant to the raw water, the operating cost can be reduced. Further, the effect that the cleaning of the packed bed becomes very simple is obtained.
[Brief description of the drawings]
FIG. 1 is a schematic explanatory view showing one embodiment of a filtration device of the present invention.
FIG. 2 is a schematic explanatory view showing one embodiment of a fiber bundle cord-like member.
FIG. 3 is a schematic explanatory view showing one embodiment of a string member with a fringe.
FIG. 4 is a partially cutaway perspective view showing one embodiment of a fiber filter medium as a modification of the cord-like member.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Raw water 2 Filtrated water 3 Filtration device 4 String member 5 Filling layer 6 Suspension member 7 Water surface 8 Light weight 9 Air diffuser 10 Air 11 Blower 12 Washing drainage 13 Warp 14 Fringe 15 Bundled long fiber bundle 16 String member 17 Attachment Part 18 Fiber filter medium 18a Core string 18b Loop thread 18c Filament bundle 18d Power thread 18e Ring net 18f Adhesive tape

Claims (3)

A string-like member or a fiber-bundle string-like member with a synthetic fiber thread fringe (brown hair) is fixed inside the tower, and the upper end is fixed with a fixing member, and suspended water flows in from the lower part of the filtration tower in which a large number is suspended. An upflow filtration method for suspension water, wherein the filtration is performed by passing the water as a stream, and the filtered water is allowed to flow out from above. A string member or a fiber bundle string member with a synthetic fiber yarn fringe (bristles) is provided inside a filtration tower provided with a suspension water inflow portion at a lower portion and a filtered water outflow portion at an upper portion, and a fixing member at an upper end. An upflow filter for suspended water, which is fixed and drooped in large numbers. The filtering device according to claim 2, wherein the lower end of the string-shaped member is suspended as a free end.

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