JP2011167584A - Contact filter medium molding, method for producing the same and filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a contact filter medium molding which attains further improvement of water quality improving effect while employing features of lightweight, good water passing property and water quality improving effect that conventional contact filter medium molding comprising a solidified accumulated material of a thermoplastic resin strand has. <P>SOLUTION: The contact filter medium molding comprises the solidified accumulated material of a molten thermoplastic resin strand as a whole and a plurality of high density filling accumulated lumps H1 to H9 and a low density filling region coexist. A thermoplastic resin in a thermally molten state is extruded to a strand form from a die opening to flow down into a frame body having a definite opening shape in its horizontal direction and to be accumulated in the frame body. At that time, the frame body is intermittently and repeatedly moved in a horizontal two-dimensional direction with respect to the flowing strand and the strand is cooled during flowing-down. Intermittent relative movement of the frame body in the horizontal two-dimensional direction respectively forms a plurality of high density filling accumulated lumps during a period of stopping or of deceleration moving and the low density filling region during a moving period. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a contact filter medium molded body suitable for use in purification of polluted water, an efficient manufacturing method thereof, and a filtration device including the contact filter medium molded body.

  In order to purify polluted water including river water, domestic wastewater, industrial wastewater, etc., porous to promote physical contact precipitation and / or biochemical contact reaction (oxidation and / or reduction) by attached microorganisms Quality contact media is used. For example, it is known to use a three-dimensional net-shaped molded body made of a synthetic resin (Non-patent Document 1). Among them, for example, a non-woven mat-shaped molded article has a thermoplastic resin filament facing downward from a spinning nozzle. It is said that it is obtained by spinning up and moving the conveyor arranged below it without interruption, and depositing a plurality of filaments in a loop shape and cooling and solidifying (Patent Documents 1 and 2). Nonwoven mat-shaped contact filter media formed in this way generally have a porosity of over 90% and good water permeability, but poor water quality improvement. Although the porosity can be reduced by compressing, when the filter medium once solidified is forcibly compressed, a bias in the compressibility, and hence in the porosity, tends to occur, and the flow of the treated water (contaminated water) tends to occur. . There is also a problem that it is difficult to form a contact filter medium that can accommodate a large wastewater treatment facility. On the other hand, by reducing the porosity, the water quality improvement effect, particularly the COD reduction effect is increased, and a plurality of crushed stones having an average diameter of 1 to 3 cm are joined by cement to form an aggregate having an average diameter of about 5 to 20 cm. A contact filter medium has been proposed (Patent Document 3). However, this contact filter has a good balance between water permeability and water quality improvement effect, but it has a heavy specific gravity of 2.6 or more, which increases transportation costs and requires a water treatment tank with load resistance. In addition, there are problems such as an increase in costs for construction and maintenance, and further improvement of the water quality improvement effect is desired.

  In view of the circumstances described above, the present inventors have already stated that "one horizontal strand deposition layer consisting of a solidified deposit of molten thermoplastic resin strands and consisting of strands extending generally in the X-axis direction, and generally orthogonal to the X-axis direction. Proposed a contact filter medium molded body comprising a fused strand laminate in which the next horizontal strand deposited layer consisting of strands extending in the Y-axis direction is alternately laminated in the vertical direction. (Patent Document 4). The thus formed contact filter medium molded body has a controlled porosity of 50 to 90%, is lightweight, and has the characteristics of good water permeability and water quality improvement effect. However, according to the study by the present inventors, it has been found that there is room for further improvement in the water quality improvement effect in this contact filter material molded body.

Japanese Examined Patent Publication No. 63-32907 Japanese Examined Patent Publication No. 63-32908 Japanese Patent Publication No.8-17901 JP 2009-226333 A

Ken Sato: Properties and application of solid reticulated contact material, “Water and wastewater” Vol. 23, no. 4.51-61 (1981)

  The main object of the present invention is to make use of the advantages of the above-mentioned contact filter material molded body of Patent Document 4, while further improving the water quality improvement effect, an efficient production method of the contact filter medium molded body, and the contact It is providing the filtration apparatus which arranged the filter-material molded object.

  According to further studies by the present inventors, as a whole, like the contact filter medium molded body of Patent Document 4, it is a solidified deposit of molten thermoplastic resin strands, but gives a macro density distribution thereto. Thus, it has been found that an improvement effect of the water quality improvement effect can be obtained (see Examples and Comparative Examples below). More specifically, the contact filter medium molded body of the present invention is composed of a solidified deposit of molten thermoplastic resin strands as a whole, and a plurality of high-density packed deposits and low-density packed regions are mixed. Is. The reason why an improved water quality improvement effect can be obtained by using this contact filter medium molded body is not necessarily clear, but due to the macro dense distribution of strands, the discharge discharged from the diffuser pipe disposed at the bottom of the contaminated water treatment tank As a result of the high density area acting as a hindrance to the air flow and the preferential air flow flowing in the low density area, a favorable distribution of the anaerobic and aerobic areas that govern the treatment performance of the polluted water is formed. It is presumed that due to the existence of the low density region, the sludge holding region containing a large amount of microorganisms also extends above the treatment tank and the amount of sludge retained increases. According to a preferred embodiment, the contact filter medium molded body of the present invention is formed by arranging a plurality of high-density packed deposits in a planar manner via a low-density packed region.

  The present invention also provides an efficient method for producing the contact filter material molded body of the preferred embodiment. That is, in the method for producing a contact filter medium molded body of the present invention, a thermoplastic resin in a heated and melted body is extruded into a strand shape from a die opening, and is allowed to flow down and accumulate in a frame having a certain horizontal opening shape. , And intermittently repeatedly moving in the horizontal two-dimensional direction with respect to the strand flowing down the frame, and cooling the strand in the flowing direction, the horizontal two-dimensional intermittent relative movement is stopped or decelerated. It is characterized by comprising a period and a movement period, and forming a plurality of high-density packed deposits during the stop or deceleration movement period and a low-density packed region during the movement period.

  The horizontal two-dimensional direction intermittent relative movement is typically formed by a stop period and a movement period, but instead of the stop period, the deceleration movement period (the movement speed in the movement direction in the movement period is slow). And the case where the moving speed in the same direction becomes slower as a whole due to repeated short-period reciprocating movements) can be easily formed. be able to.

  Furthermore, the polluted water filtering apparatus of the present invention is characterized in that a plurality of the contact filter medium molded bodies are arranged in a polluted water treatment tank.

The schematic perspective view of one Example of the contact filter material molded object according to the preferable aspect of this invention. The schematic side view (YZ side view) seen from the left (X-axis direction) of the contact filter-material molded object of FIG. The schematic arrangement drawing of the apparatus system suitable for implementation of the manufacturing method of the contact filter material molded object of this invention. FIG. 4 is a plan view showing an example of the arrangement of die openings (houndstooth arrangement) used in the apparatus of FIG. The schematic plan view which shows an example of the sequence of the horizontal two-dimensional direction intermittent drop direction of the strand in a frame.

  FIG. 1 is a schematic perspective view of an embodiment of a contact filter material molded body of the present invention. In this contact filter medium molded body, a plurality (9 in this example) of high-density packed deposits H1 to H9 each consisting of solidified deposits of thermoplastic resin strands are arranged in rows and columns in the X-axis direction and the Y-axis direction perpendicular thereto. A low-density packed region is interposed in a hollow shape between adjacent high-density packed piles. FIG. 2 is a side view (YZ side view) of a further simplified contact filter material molded body viewed from the left side (X-axis direction) of FIG. 1, and is a high-density packed deposit H1 to H3 (further, H4). -H9) each has a cylindrical shape whose top portion is approximately the shape of a part of a sphere, and a low-density filling region L is interposed therebetween. Each of the high-density filled deposits H1 to H3 further includes three core portions H that are high-density filling and a surface layer portion M that is medium-density filling that covers the core portions H.

(Thermoplastic resin)
As the thermoplastic resin used as the main raw material of the contact filter material molded body of the present invention, a hydrophobic thermoplastic resin having a specific gravity of about 0.9 or more and preferably hydrophobic is generally used. If the specific gravity is too small, special consideration is required for preventing the filter medium from floating during water treatment, which is not preferable. Polyolefin resins such as polyethylene and polypropylene, and general-purpose resins such as polystyrene resin are preferable from the viewpoint of economy, and product filter media are generally used for primary treatment of polluted water such as river water, domestic wastewater, and factory wastewater. In view of this, waste plastic materials are also preferably used. However, it is preferable not to contain an excess plasticizer. In addition, two or more types of resins with different specific gravities, for example, a mixed system of resins such as polyethylene and polyvinylidene chloride, polyvinyl chloride, and polyvinylidene fluoride, and a mixed system of various resins and inorganic substances such as calcium carbonate have a specific gravity of around 1. It is preferably used to adjust to.

  An apparatus system similar to that used in Patent Document 4 is used as an apparatus system for producing a contact filter material molded body by the method of the present invention using the thermoplastic resin as described above. FIG. 3 is a schematic diagram of a simple example of such an apparatus system. Referring to FIG. 3, heating and melting extruded from an opening (orifice) 2 a (normally a plurality as shown in FIG. 4, but only one is shown in FIG. 3) of die 2 at the tip of extruder 1. The surface temperature of the thermoplastic resin strand 3 in the state is detected by a non-contact type thermometer (thermography) 4, and under the action of mist-like water 5 a controlled to be ejected from the water spray cooler 5 according to the output. To be cooled. The cooled strand is flowed down and deposited in a molding frame 7 that is placed on the moving device 6 and moves two-dimensionally in the horizontal direction, and finally solidifies to form the contact filter medium of the present invention. The details of these steps will be described sequentially.

(Formation of thermoplastic resin strands)
The above-mentioned thermoplastic resin is melted and kneaded by an extruder 1 or the like, and extruded from the die opening 2a into a strand 3 shape to flow down. The extrusion temperature from the die 2 refers to the melting point and crystallization temperature of the thermoplastic resin used (here, the endothermic and exothermic peak temperatures in the process of raising and lowering the temperature with a differential scanning calorimeter (DSC), respectively). In general, a range of melting point +30 to + 150 ° C. is preferably used.

  In general, it has been found that the strand diameter in the formed filter medium molded body has an important influence on the porosity that governs the water permeability and water quality improvement effect. The decrease in the diameter of the strand 3 during the flow is essentially unscheduled (however, about 5 to 10% can occur), and the die opening diameter is 0.5 to 10 mm, more preferably 1 to 8 mm, particularly preferably. Is preferably in the range of 1.5 to 6 mm. When extruded with high viscosity, it is possible to obtain a strand having a diameter larger than that of the die opening due to a die swell phenomenon.

(cooling)
The thermoplastic resin strand extruded from the die opening is allowed to flow down and accumulate in the frame while being cooled, and the surface temperature of the strand that flows down (drops) into the frame through the experiment is also determined. For the purpose of the present invention, which influences the degree of mutual fusion, the crystallization temperature of the thermoplastic resin forming the strand is preferably in the range of -20 ° C to room temperature.

  In order to control the surface temperature of the strand 3, it is preferable to control the refrigerant supply amount (further refrigerant supply temperature if necessary) while measuring the surface temperature with a non-contact thermometer (thermostat) 4. . It is preferable to use mist-like water (a mixture of water and air) 5a as the refrigerant. Depending on the air (gas) with a small heat capacity, the desired cooling surface temperature cannot be obtained, causing excessive fusion of the strands flowing down into the frame, and in the case of a thick strand, the deformation due to its own weight completes solidification. It occurs before and the porosity of the molded body is excessively lowered. In addition, when only water with a large heat capacity is used, the temperature difference between the surface and the inside of the strand becomes small, so that it becomes difficult to shape the strand in the molded body with appropriate fusion between the strands, and the porosity is low. It becomes excessive and the water quality improvement effect tends to decrease.

(Intermittent relative movement of strand and frame)
When the intermediate-cooled thermoplastic resin strand 3 flows down and is deposited in the frame body 7, the frame body is repeatedly moved in the horizontal direction relative to the flowing-down strands. Since it is a relative movement, the frame body may be fixed and the flowing strand may be moved, or the flowing strand and the frame body may be moved in one or two dimensions, respectively. The horizontal movement of the strand in the flow can be achieved by moving an extruder with a fixed die along with its base, or by swinging the die with respect to the extruder body instead of or in addition to the movement of the extruder. Can be achieved. However, in the method of the present invention in which cooling is performed while the strands are flowing, the horizontal position of the strands that flow down is fixed by moving the cooling strands in the horizontal direction. Moving the body in a two-dimensional direction is convenient for producing a small-scale filter medium molded body. On the other hand, when considering application to a large wastewater treatment facility, or when considering the production of a large-scale filter medium molded body, the filter medium molded body having a large size (at least in one direction) as required ( Semi-continuous production is desirable. For this purpose, it is preferable to use both the movement of the frame and the movement of the strand in the flow, for example, the frame is placed on a conveyor that moves (reciprocates) only in one direction (for example, the X-axis direction), Two-dimensional relative movement is realized by moving the nozzle in the Y-axis direction orthogonal to this and / or moving the strand during the flow by swinging, and arranging a plurality of conveyors in parallel or in series as necessary. Semi-continuous manufacturing can be performed by switching to the frame on the adjacent conveyor when the deposition of the strands on one frame is completed and continuing the deposition of the strands that subsequently flow down.

  In accordance with the method for manufacturing a contact filter material molded body of the present invention, a plurality of high-density packed deposits and intermediate low-density packed regions are obtained by intermittently moving the frame 7 and the strand 3 flowing down in the horizontal two-dimensional direction. And a preferred contact filter medium molded body of the present invention in which the and are arranged in a plane. More specifically, the horizontal two-dimensional intermittent intermittent movement is performed by alternately repeating a stop or deceleration movement period and a movement period, and a plurality of high-density packed deposits are sequentially formed during the stop or deceleration movement period. A low-density filling region is formed during the movement period.

  If the above-mentioned intermittent movement condition is satisfied, the two-dimensional relative movement mode is finally improved in the degree of fusion by applying a load before completely solidifying the strand flowing down and deposited in the frame and the porosity. In view of the shaping process as an optional process adopted as necessary for reducing the above, there is relatively arbitrary. However, in this case, if the degree of arbitrary two-dimensional movement is high, excessive deformation of the strand at the center and excessive reduction of the porosity at the peripheral portion tend to occur during molding by applying a load. Therefore, it is preferable to provide a certain degree of regularity in the relative two-dimensional relative movement direction of the frame body with respect to the nozzle, and to rectify the water flow to be treated through the filter medium through a uniform distribution of the porosity in the molded body.

  On the other hand, the overall shape of the filter medium molded body obtained by the method of the present invention is basically governed by the shape of the frame used, but considering the use as a filter medium unit stacked in the water treatment apparatus. In general, the shape is preferably a rectangular parallelepiped (intended to include a cube). Accordingly, the horizontal opening shape of the frame used is preferably rectangular (including a square).

  As an example of a preferable aspect of the direction order of the horizontal two-dimensional movement of the frame body, in other words, the flow (down) of the cooling strand into the frame body, a frame body 7 having a rectangular horizontal opening shape is used. 1 and FIG. 2, the example of forming the contact filter medium molded body (Example 1 described later) will be described. The extending direction of both sides of the rectangle is the X axis, the Y axis, and the vertical direction is the Z axis. In this case, as shown in FIG. 5 which is a plan view from above the opening (50 cm × 50 cm) of the frame body 7, in the first cycle, as shown by the solid line arrows, the dropping positions are sequentially lowered from the points P1 to P9. In the second cycle, as shown by the dash (-) line arrow, P9.fwdarw.P4.fwdarw.P3.fwdarw.P2.fwdarw.P5.fwdarw.P8.fwdarw.P7.fwdarw.P6.fwdarw.P1, and in the third cycle P1 as shown by the dotted arrow. Again from P9 to P9 In the middle, the moving speed between each point is 30 mm / second in both the X-axis and Y-axis directions, the moving distance is 178 mm in the X-axis direction, 182 mm in the Y-axis direction, and the stop period at P1 of the first cycle is about 20 seconds, the stop period at the transition point P9 from the first cycle to the second cycle, the stop period at the transition point P1 from the second cycle to the third cycle, and the stop period at the final point P9 of the third cycle Is about 30 seconds, and the stop period at other points is about 15 seconds. By performing horizontal two-dimensional intermittent movement, as shown in FIG. 1 and FIG. 2, the stop point P1 in the frame 7 is obtained. Corresponding to ~ P9, a contact filter medium molded body according to a preferred embodiment of the present invention in which the high-density packed deposits H1 to H9 are respectively formed is formed. Further, as shown in FIG. 2, a hollow low-density packed region L corresponding to the moving period is formed between the high-density packed deposits, and the high-density packed deposits H1 to H3 (and H4 to H9) are formed. In each of these, a core portion H that is three-stage high-density filling and a surface layer portion M that is medium-density filling are formed around the core H corresponding to the stop period of each cycle. This is because, at the stop position, the density of the strand that accumulates changes in the lower part from the center of the die 2 and the lower part from the peripheral part, but the boundary between the core part H and the surface layer part M is not clear. . Further, in order to evenly accumulate the contact filter medium in the water treatment tank, it is desirable that the height of the high-density packed deposits H1 to H9 is substantially equal in the Z-axis direction, so the total stop time at a specific location is substantially constant. It is desirable that

  In the above horizontal two-dimensional intermittent relative movement, if a deceleration movement period (including the case of repeated short-period reciprocation) is used instead of a stop period, high-density filling with a planar dimension that is larger than the area of the die 2 A sediment mass is formed.

(Shaping process)
If the strand deposit flowing down into the frame as described above is taken out of the frame after solidification, the filter medium molded body according to the present invention can be obtained. However, in order to adjust the overall filling rate, including the filling rate of the low-density filling region, before the strand deposits in the frame are completely solidified, the upper lid body is inserted into the frame opening. It is also possible to apply a load of about 10 to 80 kg / m ² to the strand deposit to reinforce the adhesion between the strands and to adjust the direction in which the porosity is reduced.

(Contact media)
The filter medium molded body according to the present invention can be obtained by taking out the strand laminated body in the frame subjected to the above-described steps from the frame after solidification. In the example shown in FIG. 3, the frame body 7 does not have a bottom plate, and the top surface is placed on the top plate of the moving device 6 made of a resin having good releasability (for example, stainless steel). The filter medium molded body can be easily taken out from the frame body 7.

  In the low-density packed region L between the high-density packed piles, bridging strands that are solidified strands flowing down during the moving period will be present. If this bridging strand is insufficient, it will be extruded from the die. It is possible to increase the number of bridging strands by moving part of the thermoplastic resin strands independently of other strands. It is preferably used for improving the strength of the contact filter medium, improving the filling rate of the low filling rate region, and complicating the drainage flow path.

(Modification)
In the above, the contact filter medium molded body of the present invention in which a plurality of high-density packed deposits according to a preferred embodiment of the present invention are arranged in a plane via a low-density packed region and a method for manufacturing the same are described. However, the contact filter medium molded body of the present invention is somewhat relaxed in the regularity of the distribution of the high-density packed deposit mass as compared with the preferred embodiment, and generally has a plurality of high-density packed deposit mass, a low-density packed region, It is characterized by a macro sparse / dense distribution. A contact filter medium molded body in which such high-density packed deposits are present in a more irregular distribution separately forms a high-density packed deposit (or a block corresponding to the high-density packed core). It can be formed by appropriately putting it into a forming frame in the middle of forming the conventional uniform low density packed filter medium according to the method of Document 4 and solidifying it as a whole.

(Dense distribution)
According to a preferred aspect of the contact filter medium molded body of the present invention, when the total volume of the contact filter medium molded body formed as described above is substantially the same volume (rectangular shape) as the filling portion internal volume of the frame body 7, The total volume of the densely packed pile is about 20 to 70%, the strand filling ratio is about 15 to 60%, the volume ratio of the core H is about 5 to 60% (the volume of each core H is 10 ² to 10 ⁴ cm ³ ), the filling rate is about 25 to 60%, the filling rate of the remaining surface layer portion M is 10 to 50% (15 to 75% of the core portion filling rate), and the total volume of the contact filter medium molded body The region other than the high-density packed lump, that is, the strand filling rate in the low-density packed region L is approximately 1 to 20% (2 to 60% of the high-density packed lump filling rate). Although somewhat arbitrary remains about the method of making the boundary between each area | region, it seems that the outline of the density distribution in the contact filter material molded body of this invention is understandable.

(Filtration device)
The polluted water filtration device of the present invention is formed by arranging a plurality of the above-described contact filter medium molded bodies of the present invention in a polluted water treatment tank, but the contact filter medium molded body of the present invention is formed as described above. It is preferable that a plurality of layers of the unit contact filter medium formed are laminated and used in the Z-axis direction. The low-density packed region L in the contact medium molded body laminated in this way functions as a sludge holding portion having a high treatment effect of contaminated water containing a large amount of microorganisms even in the upper portion of the contaminated water treatment tank. When arranging the contact filter media molded bodies thus laminated in the polluted water treatment tank, the layer of the unit contact filter media molded bodies is parallel to the flow path of the polluted water flowing in the polluted water treatment tank, or They can be arranged to be vertical. In the case of the parallel arrangement, since the low density filling region portion is almost in communication with the flow path direction, clogging of SS (floating matter) is reduced, which is particularly advantageous for wastewater treatment with a high SS concentration. On the other hand, in the case of the vertical arrangement, the surface formed by the bridging strand portion is orthogonal to the direction of the drainage flow path, so this surface plays a role of filtering, promotes long-term residence of SS, and BOD (biochemical oxygen demand) ) And SS are improved.

  Further, in the filtration device of the present invention, along the flow path of the polluted water flowing in the polluted water treatment tank, before and / or after the arrangement portion of the contact filter material molded body (densely packed contact filter medium molded body) of the present invention. It is also preferable to arrange a contact filter medium molded body (uniform density contact filter medium molded body) made of a solidified deposit of thermoplastic resin strands having a substantially uniform packing density as disclosed in Patent Document 4.

  In particular, the uniform density contact filter medium molded body of relatively thick strands is disposed in the first half of the flow path, and the densely packed contact filter medium molded body of the present invention having a high sludge retention function is disposed in the latter half of the sludge. It is preferable for effectively utilizing the function of treating contaminated water with microorganisms. On the other hand, when sewage or high-concentration SS factory effluent is introduced directly into a polluted water treatment tank without passing through a settling basin, the present invention having a relatively large strand diameter in which the unit contact filter medium molded body layer is disposed in the flow path. In order to improve the drainage treatment function, a layered product of the contact filter media molded body is arranged in the first half to prevent clogging, and a uniform density contact filter media molded body with a relatively small strand diameter or gradually decreasing is arranged in the second half. It is also preferable to use it.

  Regardless of the arrangement mode of the contact filter medium molded body in the polluted water treatment tank, it is preferable to enhance the aerobic treatment function by arranging a diffuser tube at an appropriate interval at the bottom of the polluted water treatment tank. At this time, the low-density packed region in the contact filter medium molded body of the present invention mainly functions as an aerobic processing part, and the high-density packed deposit functions as a relatively anaerobic processing part.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.

(Production Example 1)
A filter medium molded body was manufactured using an apparatus system as shown in FIG. 3 using the waste polyethylene for wire coating having the following properties as a thermoplastic resin.

MFR value (based on JIS-K7210): 5.8 g / min (measurement temperature: 190 ° C., load: 10 kg · f),
Melting point: 110 ° C., crystallization temperature: 97 ° C. (temperature increase / decrease rate: 10 ° C./min),
Density: 0.92 g / cm ³ .

  The polyethylene is melt-kneaded with a single screw extruder 1 having a cylinder temperature of 150 ° C., and a total of 21 openings 2a (diameter 3) in a staggered lattice arrangement shown in FIG. 2 provided in a fixed die 2 (temperature: 125 ° C.). The surface temperature was adjusted by a non-contact type surface thermometer 4 (“TH6200” manufactured by NEC Sanei Co., Ltd.) while the strand 3 extruded from the adjacent openings was about 15 mm in both length and width. The water spray cooler 5 is sprayed and cooled with water adjusted to a spray rate of 0.64 liters / minute while measuring, and the horizontal biaxial moving device 6 equipped with the servo motor is moved to the upper end of the frame. The strands flowed down while continuously moving the molding frame 7 having a size of 50 × 50/25 cm (X / Y / Z) placed so that the distance is 120 cm below the nozzle in the X-axis and Y-axis directions. I let you. Details of the intermittent movement of the frame 7 in the horizontal two-dimensional direction at this time are as illustrated and described in the above text with reference to FIG. 5 which is a plan view seen from above the opening of the frame 7. Strands were deposited to a height of 25 cm by cycling down and depositing. Thereafter, the strand deposit was solidified in a state where an upper lid on which a load of 9.7 kg (/ 50 × 50 cm) was applied was placed. Thereafter, by taking out from the frame body 7, nine high-density packed deposits H1 to H9 are arranged in three rows and three through the low-density packed region L as shown in FIGS. 1 and 2 corresponding to the points P1 to P9. A contact filter medium molded body having an overall outer contour of 50 cm × 50 cm × height 25 cm arranged in a row was obtained.

Assuming that each of the high-density packed piles H1 to H9 of the above-mentioned contact filter medium molded body is roughly a cylinder of 13 cmφ × 250 mm (volume 3300 cm ³ ), the average filling rate of the strands was 30%. Since the average filling rate of the entire volume 62500 cm ³ (= 50 × 50 × 25) determined by the entire contour of the contact filter medium molded body was 18%, the average filling rate of the low-density packed region L around the high-density packed deposited mass is ,
(18x62500-30x3300x9) / (62500-3300x9)
= 7.1%.

Further, the surface layer portion M of the two high-density packed deposits was scraped, and six core portions H of about 11 cmφ × 7.5 cm (volume equivalent to 712 cm ³ ) were taken out and the average filling rate was measured to be 36%. Met. Therefore, the average filling rate of the surface layer part M is
(30x3300-36x712x3) / (3300-712x3)
= 19.0%.

(Water flow example 1)
In a test tank (length 100 cm × width 25 cm × depth 100 cm) made of a transparent vinyl chloride resin, the contact filter medium molded body having a strand diameter of 3.3 mmφ and dimensions of 50 cm × 50 cm × 25 cm produced in Production Example 1 is used. The filter medium divided into two parts, 50 cm long × 25 cm wide × 25 cm deep, was laminated in four stages to fit a depth of 100 cm, and this four-stage laminate was arranged in two rows along the flow path.

  Furthermore, in the test tank, three diffuser tubes extending in the width direction orthogonal to the flow path are arranged at the bottom at positions 10 cm, 50 cm, and 90 cm from the inlet, and a diameter of 1.0 mm provided at the center in the width direction. Air was blown out from each one air diffuser at 6.3 L / min.

  Under these conditions, activated sludge tank sludge water (SS: 1200 mg / L) was passed through the test tank at a feed rate of 320 L / H for 2 hours, and sludge (SS) was captured by the filter medium.

  Next, clean water (medium water: water obtained by filtering the treated water from the sewage treatment tank) was passed through the test tank at a water feed rate of 320 L / H, which was the same as sludge water, until the turbidity in the test tank became the same as that of the clear water. did. Then, after thoroughly rinsing the filter medium in the test tank and forcibly washing off the attached SS, the filter medium is withdrawn from the test tank and the amount of residual liquid in the test tank and the SS concentration in a sufficiently stirred state are measured. The amount of SS retained on the filter medium was determined to be 597 g.

(Water flow comparison example 1)
In place of the two-part filter medium of the contact filter medium molded body obtained in Production Example 1, the strand diameter 3.3 mm obtained in Example 1 of Patent Document 4 was obtained by dividing the dimension 50 cm × 50 cm × 25 cm into two. A water flow test was conducted in the same manner as in the water flow Example 1 except that a filter medium having a length of 50 cm, a width of 25 cm, and a depth of 25 cm was used (average filling rate: 18%). there were.

  From the comparison of the water flow example 1 and the comparative example 1, the dense contact filter medium molded body of the present invention has a sludge retention amount 1.1 times larger than the uniform density contact filter medium molded body of Patent Document 4. It can be seen that the effect of improving the quality of treated water can be expected through the increase of microorganisms contained in the sludge.

  Further, as an observation result through the outer wall of the visualization test tank, in Example 1, the bubbles are subdivided in the high filling rate region portion, and the high filling rate region portion acts as a baffle plate. Bubbles flowed. Therefore, regarding the repetition of anaerobic treatment / aerobic treatment that governs wastewater treatment performance, the effect of the wastewater treatment tank is subdivided into anaerobic and aerobic areas, and the difference becomes clear, making the effect more obvious Is expected to do.

  Furthermore, in Comparative Example 1, most of the sludge accumulation was unevenly distributed at the bottom, whereas in Example 1, sludge accumulation was observed over the entire layer. That is, since sludge is dispersed and accumulated in the vicinity of the strands constituting the contact filter medium, an effect can be expected for sludge reduction.

  Moreover, in Example 1, since there is much sludge accumulation of the upper layer part compared with the comparative example 1, the difference of a sludge retention rate becomes large and the improvement of processing performance will be remarkable, so that the depth of a waste water treatment tank increases. .

(Water flow example 2)
In addition to the formed compact contact filter material having a strand diameter of 3.3 mmφ and 50 cm × 50 cm × 25 cm obtained in Production Example 1, a strand diameter of 5.5 mmφ (average filling rate) obtained in Example 5 of Patent Document 4 : 18%) uniform density contact filter medium compact.

  A uniform density contact filter material molded body is arranged in a length of 1 m upstream of a test tank of length 2 m × width 0.5 m × depth 0.5 m, with its XY plane parallel to the flow path, and downstream In the 1 m length, the sparse contact filter medium molded body was arranged and filled so that its XY plane (unit contact filter medium molded body layer) was parallel to the flow path.

  At the bottom of the test tank, eight diffuser tubes (each with a diameter of 7 mm / hole each having a hole diameter of 1 mmφ) are provided at equal intervals in the length direction so as to be orthogonal to the length (flow path) direction. ) To 55 at a rate of 55 L / min.

  Under the above conditions, wastewater from the food factory was fed into the test tank as inflow raw water at a flow rate of 130 mL / min (residence time: 64 hours), and a treatment test for a total of 12 weeks was conducted to evaluate the treated water.

(Water flow comparison example 2)
Only the strand diameter 5.5 mmφ (average filling rate: 18%) obtained in the water flow example 2 is the same size as that used in the water flow example 2 and is 2 m long and 0.3 mm wide arranged in parallel. Except for filling the entire length of a 5 m × 0.5 m deep test tank, a parallel treatment test was conducted in the same manner as in Example 2 to evaluate the treated water.

  BOD and SS of the raw water and treated water flowing into the experimental tank were measured at a rate of once / week, and the average values thereof and the BOD removal rate, SS removal rate, and sludge conversion rate according to the following formulas were obtained.

BOD removal rate (%) = (raw water BOD−treated water BOD) / raw water BOD × 100
SS removal rate (%) = (raw water SS−treated water SS) / raw water SS × 100
Sludge conversion rate (%) = treated water SS amount / treated BOD amount × 100
The average water quality of the influent raw water was BOD: 617 mg / L, SS: 315 mg / L.

The evaluation results regarding water purification and sludge conversion rate in the above Examples and Comparative Examples are summarized in Table 1 below.

  Comparing the results of Example 2 and Comparative Example 2 above, in Example 2 using the compact contact filter molded body of the present invention, through BOD removal rate, significant improvement in SS removal rate and significant reduction in sludge conversion rate, Significant improvement in water quality improvement effect is observed.

  As described above, according to the present invention, the water density improvement effect is further improved while taking advantage of the light weight and good water permeability and water quality improvement effect of the uniform density contact filter material molded body of Patent Document 4 described above. There are provided a contact filter medium molded body having a dense distribution that achieves the above, an efficient method for producing the contact filter medium molded body, and a filtration device including the contact filter medium molded body.

H1 to H9: High density packed sediment L: Low density packed region H: High density packed core part M: Medium density packed surface layer part P1 to P9: Strand dropping point in frame during stop period 1: Extruder , 2: Die (2a: Die opening), 3: Strand 6: Horizontal two-dimensional moving device, 7: Molded frame.

Claims (15)

A contact filter material molded body comprising a solidified deposit of molten thermoplastic resin strands as a whole, wherein a plurality of high-density packed deposits and a low-density packed region coexist. The contact filter material molded body according to claim 1, wherein the plurality of high-density packed piles are arranged in a plane via low-density packed regions. 3. The contact filter medium molded body according to claim 1, wherein the high-density packed deposit includes a core portion having high-density filling and a medium-density-filling surface layer portion covering the core portion. The contact filter-material molded object in any one of Claims 1-3 with which the adjacent high-density filling deposit lump is connected by the thermoplastic resin strand solidified material in the low-density filling area | region. The contact filter material molded body according to any one of claims 2 to 4, wherein the plurality of high-density packed piles are arranged in a plane in a plurality of rows and a plurality of columns. The contact filter material molded body according to any one of claims 2 to 5, wherein a top portion of the high-density packed pile has a shape of a part of a sphere. A laminated contact filter medium molded body obtained by laminating a plurality of layers of the contact filter medium molded body according to claim 1. When the thermoplastic resin in the heated melt is extruded in a strand form from the die opening, and flows and deposits in a frame having a certain horizontal opening shape, the horizontal two-dimensional direction with respect to the strand flowing down the frame The horizontal two-dimensional direction intermittent relative movement consists of a stop or deceleration movement period and a movement period, and the stop or deceleration movement period. 7. The method for producing a contact filter material molded body according to claim 2, wherein a plurality of high-density packed deposits are formed and a low-density packed region is formed during the movement period. The horizontal two-dimensional direction intermittent relative movement includes a stop period and a movement period, and a plurality of high-density packed deposits are formed in the stop period, and a low-density packed region is formed in the movement period, respectively. The manufacturing method according to claim 8. An apparatus for filtering polluted water in which a plurality of the contact filter medium molded bodies according to claim 1 are arranged in a polluted water treatment tank. The filtration device according to claim 10, wherein a plurality of layers of the contact filter medium molded body are arranged in a polluted water treatment tank in a laminated state. The filtration device according to claim 11, wherein the contact filter material molded body layer is laminated and arranged so as to be parallel to a flow path of the polluted water flowing in the polluted water treatment tank. The filtration device according to claim 11, wherein the contact filter medium molded body layer is laminated and arranged so as to be orthogonal to the flow path of the polluted water flowing in the polluted water treatment layer. A substantially uniform packing density before and / or after the arrangement of the contact filter medium molded bodies according to any one of claims 1 to 6, along the flow path of the polluted water flowing in the polluted water treatment tank. The filtration device according to any one of claims 10 to 13, wherein a contact filter medium molded body made of a solidified deposit of thermoplastic resin strands is arranged. The filtration apparatus according to any one of claims 10 to 14, wherein a diffuser pipe extending in a direction orthogonal to the flow path of the polluted water flowing in the polluted water treatment tank is provided at the bottom of the polluted water treatment tank.