KR20100126755A - Process for producing shaped contact-filtration member, shaped contact-filtration member, filtration apparatus, and method of processing soiled water - Google Patents

Abstract

Extruding the hot melt thermoplastic resin in the form of a strand through a nozzle, and dripping and depositing the strand into a frame having an opening having a predetermined horizontal shape, wherein the frame is horizontal with respect to the strand of thermoplastic resin falling down. Which is moved in two dimensions, and the falling strands are cooled so that the strands are dropped and deposited into the frame in a semi-solid state, thereby providing a final contact filter medium molded body having a controlled porosity of 50 to 90%. This is disclosed. The thus formed contact filter medium molded body includes a molten bonded strand laminate in the form of a solidified deposited product of molten strand of thermoplastic resin, and a plurality of stacked strand horizontal layers are laminated in a vertical direction. The contact filter medium is light in weight and shows a good balance of water and water quality improvement effects. By arranging a plurality of types of contact filter media molded bodies so that the diameter of the thermoplastic resin strands is sequentially reduced, it shows an excellent water quality improvement effect and a little increase in water filtration pressure, and is particularly suitable for various wastewaters having high pollution degree. An apparatus is provided, and a method of treating sewage using a filtration apparatus is also provided.

Description

Manufacturing method of contact filter medium molded body, contact filter medium molded body, filtration apparatus and sewage treatment method {PROCESS FOR PRODUCING SHAPED CONTACT-FILTRATION MEMBER

TECHNICAL FIELD The present invention relates to a process for producing a contact filter medium molded body, a contact filter medium molded body having excellent water permeability and water quality improvement effect, and a wastewater treatment method and a filtration device using the contact filter medium molded body.

Porous contact filter media are used to purify sewage, including streams, domestic drainage and factory wastewater, and to promote biochemical contact reactions (oxidation or reduction) with the aid of physical contact deposits and / or adherent microorganisms. . For example, a thermoplastic string is spun downward through a spinning nozzle, the thread is deposited onto a conveyor that is constantly moving up and down, and the thread is cooled and solidified to form a loop of a plurality of deposited threads. Three-dimensional net molded articles of synthetic resins are known (including nonwoven mat shaped articles) (patent documents 1 below). The nonwoven mat shaped bodies thus formed generally have a porosity of greater than 90%, showing good water flow, but poor water quality improving performance. Porosity can be reduced by compression, but once the solidified filter medium is forcibly compressed, the compression ratio is likely to be biased locally, resulting in a drift of the treated water (sewage). In addition, the above-described manufacturing process also has a problem that it is difficult to form a contact filter medium applicable to a large-scale wastewater treatment facility. On the other hand, in order to improve the water quality improvement effect, in particular to increase the COD reduction effect, in the case of the contact filter medium having a low porosity, respectively formed by the cement treatment of crushed stone or gravel having an average diameter of 1 to 3 cm and 5 A contact filter medium composed of an aggregate having an average diameter of ˜20 cm has been proposed (List Patent Document 3 below). However, the contact filter medium shows an excellent balance of oil and water quality improvement effect, but is heavy by showing a specific gravity of 2.6 or more, the need of a water treatment tank having a rise in transportation prices, durability against heavy loads, and the construction and repair of water treatment facilities It entails the same difficulties as rising costs for.

On the other hand, the treatment of sewage in recent years, in particular the treatment of various heavily contaminated wastewater, is mainly carried out by the method of reducing the amount of pollutants such as biochemical oxygen demand (BOD) and suspended solids (SS) with the help of microorganisms. Lose. According to this method, the greater the amount of suspended solids, the greater the amount of contaminants to be treated. Therefore, a carrier having a large specific surface area per unit volume is required as a wastewater filter medium capable of stably supporting a large amount of biological membrane. Supports comprising small diameter threads may provide greater specific surface area and improved filtration performance. However, if the thread diameter is reduced due to constant porosity, the water-head between the inlet and the outlet of the runoff of the wastewater treatment tank is increased by decreasing the inter-thread distance and clogging the inter-thread space with increasing biological membranes to increase the filtration pressure. ) The difference is increased, and as a result, the wastewater flow rate needs to be reduced and the filtration efficiency is lowered. In order to alleviate the blockage, the practice of adopting an increased porosity of 90 to 98% (Patent Document 4) or 92 to 99% (Patent Document 5) is a phenomenon.

A water treatment facility using such a contact filter medium, which is a continuous porous body for biological treatment having a porosity of 15 to 40% and a pair of filtration continuous bodies having a porosity of 30 to 65% each disposed separately before and after the biological treatment porous body. A filtration device for water intake installations containing a porous body has also been proposed (Patent Document 6). However, the apparatus is described as requiring backwashing to prevent clogging of continuous porous bodies over time (paragraph), which is not suitable for wastewater treatment characterized by greater pollution levels.

[Non-Patent Document 1] Dato Satoshi, "Properties and Applications of Three-Dimensional Network Contact Materials"; Publications "Water and Wastewater" Vol. 23, No. 4, pp. 51-61 (1981)

 [Patent Document 1] JP-B 63-32907

 [Patent Document 2] JP-B 63-32908

 [Patent Document 3] JP-B 8-17901

 [Patent Document 4] JP-A 10-14569

 [Patent Document 5] JP-A 11-279922

 [Patent Document 6] JP-A 5-185083

In view of the above circumstances of the prior art, a main object of the present invention is to provide a contact filter medium which is light in weight and has good water flow and water quality improving effect, and also a manufacturing method thereof.

It is a further object of the present invention to provide a filtration device configured to continuously treat filth water, in particular various filthrates having a high degree of contamination, and a effluent treatment method using such a filtration device.

In the course of studying for the above-mentioned purposes, the present inventors, in view of the water quality improvement effect, including the reduction of the BOD (biological oxygen demand) and SS (floating material) that occupy a major portion of the pollutant and the mud generation rate, It was found that porosity of more than 90% adopted in the contact filter media of Documents 1 and 2 was undesirable (comparison of Examples 3 to 5 and Comparative Examples 3-2 to 5-2 to be described later). This is similar to the knowledge disclosed in Patent Document 3. However, there is a drawback that the crushed stone binder employed in Patent Document 3 is heavy. In order to provide increased porosity, the present inventors do not allow hot-melted strands or threads to be deposited in a loop form, but cools the strands cooled by the process of unloading the strands to control the mutual melting. By dropping the hot-melted thermoplastic resin strand extruded through the nozzles while allowing for deposition with adhesion, it has been found that excellent water quality improvement is achieved by contact filter media formed to have reduced porosity up to 90%. On the other hand, less than 50% porosity has a problem with the porosity of the water to be treated (Comparative Examples 3-1 to 5-1 to be described later). In addition, a unit having a shape suitable for arranging a plurality in a state of being stacked in a treatment tank from the viewpoint of applicability to a large wastewater treatment facility (for example, a dimension of 5 m width x 2 m height x 10 m or more in length). It was found that it is preferable to form the filter medium.

Based on the above-described findings, the method for producing a contact filter medium molded article according to the present invention specifically includes the steps of extruding a hot melt thermoplastic resin into a strand form through a nozzle, and flowing the strand into a frame having an opening having a predetermined horizontal shape. And depositing the frame horizontally with respect to the strands of the descending thermoplastic resin, the strands being cooled to cool and drop the strands into the frame in a semi-solid state, thereby reducing the amount to 50 to 90%. It provides a final contact filter medium molded body having controlled porosity. Incidentally, the term "nozzle" as used herein is to be taken in a broad sense to mean a stationary or movable member having holes or openings through which it is not necessary to include protrusions, through which the molten resin strand can be extruded. In particular, the representative may include respective holes formed in the extruder die as used in the examples to be described later.

We also use contact filter media moldings obtained through the process described above and provided with a characteristic strand deposition state, thereby providing uniform water through the interior of the molding while providing sufficient contact time and reduced water head for treating contaminants. It has been found possible to allow one flow to be processed. Accordingly, the contact filter medium molded article according to the present invention is based on this knowledge, and specifically includes a molten bonded strand laminate in the form of a solidified deposited product of a molten strand of thermoplastic resin, wherein a plurality of stacked strand horizontal layers are laminated in a vertical direction. do. In particular, the plurality of stacked strand horizontal layers comprises a first horizontal strand deposited layer comprising a strand extending entirely in the X axis direction and a second horizontal deposited layer comprising a strand extending in the Y axis direction which is generally perpendicular to the X axis direction. The first and second strand deposition layers are preferably laminated alternately in the vertical direction.

In addition, the wastewater filtration apparatus according to the present invention includes at least two kinds of each of the above-described contact filter medium molded bodies disposed in the wastewater treatment tank and the wastewater treatment tank, and the two or more kinds of contact filter medium molded bodies have different thicknesses from each other. And a first species comprising a thick resin strand is disposed upstream and a second species comprising a thin resin strand is disposed downstream of the sewage treatment tank. The wastewater treatment method using the above-described filtration apparatus according to the present invention includes the step of allowing the wastewater to continuously flow through two or more kinds of contact filter medium molded bodies.

More specifically, a filtration device comprising a plurality of the above-described contact filter medium molded bodies composed of melt-bonded strands of uniform thickness arranged in a sewage treatment tank generally shows excellent water quality improvement effects and long-term running stability, but is composed of relatively thin strands. Filtration devices using filter media compacts show greater water quality improvement but also tend to increase in filtration pressure (i.e. inlet outlet water head differences), leaving concern about long-term running stability (Example 3 to be described later). . On the other hand, the filtration device using the filter medium molded body composed of relatively thick strands has little tendency to increase the inlet outlet head difference and is not accompanied by the problem of long-term running stability, but it is relatively weak in improving the water quality. It is easy to see (Example 5 to be described later). On the contrary, as a result of continued research, the inventors have arranged two or more types of filter medium molded articles comprising thermoplastic resin strands having different thicknesses so that the filter medium molded articles including the thick resin strands are disposed upstream, and the filter medium comprising thin resin strands. By arranging the molded body downstream (Example 6 to be described later), it has been found that it is possible to obtain a good overall water quality improvement effect while maintaining a slight increase in the inlet and outlet water head differences, and to the filtration apparatus for sewage according to the present invention. Reached. It is not necessary to be clear why the combination of a good water quality improving effect and an inlet outlet water head increasing effect can be obtained by the above-described arrangement of the contact filter medium molded body in the filtration device for sewage according to the present invention. May be

In wastewater treatment, the gap between strands is important because the biological membranes formed on the strand compacts become thick due to the concentration of organic matter and dissolved oxygen in the wastewater. More specifically, in the first stage of wastewater treatment, the concentration of organic matter is higher than the amount of dissolved oxygen, so that the population of fibrous bacteria (so-called water cotton) grows from about 200 mm to 300 mm. The tip of the water cotton grown in the first step is cut off due to aeration to form fine suspended solids (SS), which moves downstream. In order to capture the thin SS, it is preferable that a shaped body consisting of strands of small diameter with a larger specific surface area and capable of providing a small gap between the strands is arranged downstream. In the middle of the latter half, since the concentration of the organic substance is lowered, thickening of the biological membrane on the strand formed body is not caused, so that an increase in the filtration pressure may be suppressed.

According to the present invention, there is provided a contact filter medium molded article having excellent water flow and water quality improving effects.

1 is a schematic view of an apparatus suitable for carrying out the process for producing a contact filter medium molded article according to the present invention.
2 is a plan view illustrating a zigzag arrangement of nozzles used in Example 1 of a step of manufacturing a contact filter medium molded article according to the present invention.
3 is a plan view showing a circular radial arrangement as another example of the nozzle arrangement;
4 is a plan view showing an example of relative arrangement between the arrangement direction of the zigzag array nozzle of FIG. 2 and the X-axis and Y-axis directions of preferential movement of the frame;
5 is a schematic cross-sectional view of a water treatment plant comprising a filtration device according to the invention.

(Thermoplastic)

As the thermoplastic resin used as the main raw material in the process for producing the contact filter medium molded article according to the present invention, a hydrophobic thermoplastic resin preferably having a specific gravity of at least about 0.9 may be generally used. Too low a specific gravity is undesirable because it requires additional consideration to prevent the flotation of the filter media during water treatment. General purpose resins, including polyolefin resins such as polyethylene and polypropylene, and polystyrene resins, are preferred from an economical point of view, and the product filter media is considered to be used for the primary treatment of sewage, such as rivers, domestic drainage, and plant wastewater. Plastic materials may also be used as appropriate. However, it is preferable that an excessive amount of plasticizer is not included.

(Formation of Thermoplastic Strands)

The thermoplastic resin as described above may be melt kneaded by an extruder and extruded through a nozzle (or nozzle, etc.) to form the strand, the strand then falling. In general, the extrusion temperature through the nozzle takes into account the melting point and crystallization temperature (here referred to as the endothermic peak temperature and the exothermic peak temperature during the heating and cooling process, respectively, measured by a deviation scanning calorimeter (DSC)) depending on the thermoplastic used. Thus, the melting point range may be suitably + 30 ° C to + 150 ° C.

In general, it has been found that the diameter of the strands in the filter medium molded body has a significant effect on the water flowability and the water quality improvement effect of the filter medium, and in the present invention, since the diameter reduction of the strands flowing after extrusion is not basically predicted ( A decrease of about 5 to 10% can occur), the nozzle diameter may preferably be in the range of 0.5 to 10 mm, more preferably 1 to 8 mm, particularly preferably 1.5 to 6 mm. Incidentally, when extrusion is performed at high viscosity, it is also possible to form strands having a diameter larger than the nozzle diameter by die-swell phenomenon.

(Cooling)

The thermoplastic resin strand extruded from the die is cooled, flowed down into the frame and deposited. Through experiments (eg Examples 1 and 2 and Comparative Examples 1 and 2 to be described later), the surface temperature of the strands flowing into the frame also greatly influences the porosity of the final molded body and the degree of melt-sticking between the strands. It has been found that, for the purpose of the present invention, it may be preferable to be within a range from the crystallization temperature -20 ° C to room temperature (of the thermoplastic resin forming the strand).

In order to control the surface temperature of such strands, it is preferable to control the amount of the coolant supply (additional coolant supply temperature if necessary) while measuring the surface temperature with a non-contact thermometer. As the refrigerant, fog water (generally a mixture of water and air) is generally preferred. By the use of air (or gas) with a small heat capacity, it is difficult to achieve the desired cooling surface temperature, causing excessive fusion of the strands deposited into the frame, and the coarse strands begin to deform due to their own weight before completion of the fixation. This can result in excessively low porosity of the molded body. On the other hand, when only water having a large heat capacity is used, the temperature difference between the surface and the inside of the strand is reduced, making it difficult to form the strand in the molded body caused by moderate degree of fusion between the strands, resulting in excessively large porosity and water quality. It is easy to produce the result that an improvement effect falls.

(Relative movement of strand and frame)

While flowing and depositing the intermediate cooled thermoplastic strand into the frame, the frame is repeatedly moved in the horizontal direction with respect to the falling strand. Relative movement may be achieved by moving the falling strands while fixing the frame, or by moving one of the falling strands and the frame in one or two dimensions. The horizontal movement of the descending strands moves the extruder with a fixed nozzle with its base, or rotates the nozzle in addition to (or optionally with rotation of the die relative to the extruder body) in addition to, or in addition to, the movement of the extruder. It can also be made by. However, in the process of the present invention, in which the falling strands are cooled, interlocking cooling is also required for horizontal movement of the falling strands, and it is small to move the frame two-dimensionally while fixing the horizontal position of the falling strands. It is convenient for the manufacture of the filter medium molded article. On the other hand, when considering the production of a large wastewater treatment plant or a large-scale filter medium molded body, it is preferable to carry out (semi) continuous production of the filter medium molded body in large dimensions (at least in one direction) as necessary. For this purpose, it is preferable to use the movement of the frame and the movement of the strands falling. For example, it places a frame on a conveyor that is movable (or reciprocating) in only one direction (e.g., in the X-axis direction), in order to realize two-dimensional relative movement, and the Y-axis perpendicular to the X-axis direction. It may also be achieved by the movement of the falling strand by the movement and / or rotation of the nozzle in the direction. If necessary, at the end of the deposition of the strands in one frame, a plurality of conveyors are arranged in parallel or in series in order to switch the strands still falling into another frame on the adjacent conveyor so that the deposition continues. By this, semi-continuous manufacturing becomes possible.

Figure 1 schematically shows an example of a simple device system for carrying out the manufacturing process of the contact filter medium molded article according to the present invention. The thermoplastic resin strand 3 extruded from the nozzle 2 of the tip part of the extruder 1 by heat-melting state is detected by the non-contact thermometer (thermograph) 4, and the surface temperature is detected, and the thermograph 4 is carried out. It is cooled under the action of the mist water 5a ejected from the water spray cooler 5 under the control according to the output of. The cooled strand 3 drops and deposits into the forming frame 7, which is set above the moving device 6 and moves two-dimensionally in the horizontal direction, and finally fixed, thereby forming a contact filter medium molded body according to the present invention.

The two-dimensional movement mode is a shape that may be employed when required as an optional final step for increasing the degree of fusion and reducing porosity by applying a load onto the strands falling and depositing into the frame 4 prior to complete fixation. Considering the step of adjustment, it can be relatively arbitrary. However, in this case, when the arbitrary degree of two-dimensional movement is high, application of a load for adjustment is likely to cause excessive deformation of the strand at the center and excessive porosity at the periphery. Therefore, it is desirable to rectify the flow stream of water handled through the final filter media by imparting some regularity to the two-dimensional movement of the frame relative to the nozzles to provide a uniform distribution of porosity throughout the molded body.

On the other hand, the overall shape of the filter medium molded article obtained according to the process of the present invention is basically governed by the shape of the forming frame, and considering its use as a unit filter material laminated in a water treatment facility, it is substantially rectangular (including a cube). It may be desirable to have a shape. Thus, the horizontal number shape of the frame may preferably be rectangular (including square).

A preferred embodiment of the order of horizontal two-dimensional movement of the frame (in other words, the direction of the falling or falling of the cooled strand into the frame) may be as follows. Assuming that the frame has a horizontal opening in a rectangle that includes sides that individually extend in the X- and Y-axis directions, a preferred embodiment is a horizontal strand deposition layer that includes strands that extend in the X-axis direction as a whole, and It is also possible to provide a laminate structure comprising alternately stacked or layered layers which repeat in the vertical direction of adjacent horizontal strand deposition layers comprising strands extending in the Y-axis direction orthogonal to the X-axis direction.

In other words, the relative movement order of the frames may consist of alternating repetitions in the approximately X-axis direction during the one horizontal strand deposition layer formation period and in the approximately Y-axis direction during the subsequent one horizontal strand deposition layer formation period.

More strictly, in this example, the one horizontal strand deposited layer formation period may include a travel period for a short distance in the Y axis direction at the time of switching between the reciprocating movements in the X axis direction, followed by one horizontal strand deposited layer. The formation period may include a movement period for a short distance in the X-axis direction at the time of switching between reciprocating movements in the Y-axis direction. In addition, the initial movement direction along the X axis and the Y axis is opposite to the initial movement direction along the X axis and the Y axis (for example, the -X axis direction and the -Y axis direction) in the continuous two-strand deposition layer formation period. By adopting a mode including a continuous two-strand deposited layer forming period, for example, the X-axis direction and the Y-axis direction), it is preferable that the bias in the deposited strand extension direction can be prevented as possible. As a result, in this embodiment, for each of the four strand deposited layer formation periods, the moving directions along the X and Y axes (including those at the time of switching between the reciprocating movements) become the same, and this is repeated, and the height (Z axis Deposition of the strand layer occurs in the direction of?).

In order to improve the productivity of the contact filter medium molded body, it is necessary to use a die having a plurality of nozzles to simultaneously extrude a plurality of strands to increase the extrusion amount. At this time, when a plurality of nozzles are arranged in a straight line at narrow intervals, it may be influenced by the moving direction of the frame, but the tendency for the strands falling into the frame to overlap is increased. In particular, when the stiffness of the strand is insufficient due to insufficient crystallization, for example, irregular deformation of the strand is likely to be caused remarkably due to overlapping. In contrast, if the strand resin retains some stiffness by moderate crystallization, the falling strand may escape and accumulate in adjacent positions, even if the falling strand is likely to overlap with the already deposited strand. , Nesting can be roughly avoided. To better avoid strand overlap, plural nozzles may be arranged in a zigzag fashion as shown in FIG. 2 or in a circular radial fashion as shown in FIG. It is desirable to avoid arrangement. Further, with respect to the zigzag arrangement shown in Fig. 2, as shown in Fig. 4, the linear arrangement direction of the nozzles is shifted from any one of the X axis and the Y axis for the relative movement of the frame, i.e., the X axis or the Y axis It is preferred to form an inclination angle [theta] of less than 45 degrees, preferably about 5 to 30 degrees.

(Standard stage)

The strand laminate product thus formed by dropping and depositing into the frame may be taken out of the frame after solidification to provide a filter medium molded article according to the present invention. However, to provide a molded body that better fits the frame shape and has a more uniform overall porosity, about 10 onto strands deposited in the frame through an upper lid that fits into the frame opening before the fixation is complete. By applying a load of ˜80 kg / m ² , it is desirable to improve the adhesion between the strands and to reduce the porosity uniformly.

(Contact filter medium)

By removing the strand laminate formed through the above-mentioned steps from the frame after its fixing, the filter medium molded article according to the present invention can be obtained. In the embodiment shown in FIG. 1, the frame 7 is placed on an upper plate formed of a material (eg stainless) that does not have a bottom plate and shows good release potential from the resin of the moving device 6. The molded body can be easily taken out from the frame 7.

The filter medium of the present invention thus formed may preferably have a generally rectangular parallelepiped shape as a whole, but may have one or two sides (for example, one or two sides opposing each other in the Ｙ-Z plane) within a range of ± 20 degrees from the vertical. By inclining, it is also preferable to alternately arrange a pair of adjacent molded bodies including one molded body having an upwardly decreasing cross section and another formed body having an upwardly increasing area, thereby stabilizing the mutual arrangement of the molded bodies in a water treatment facility. Do.

As another preferred physical feature of the contact filter media according to the invention, the element strand diameter (based on the diameter of a circle having an equal area) is 0.5 to 10 mm, more preferably 1 to 8 mm, particularly preferably 1.5 to 6 mm. [d (mm)], porosity [ε (%)], 50 to 90%, preferably 70 to 85%, more preferably 75 to 80%, the length of the urea strand at least 2 m, in particular 10 m or more [ L (m)], the specific surface area [S (m ² / m ³ )] of 50 to 5000 m ² / m ³ , and the total volume of the molded body of 10 ⁻² to 10 ² m ³ , and the like. The filter medium molded article obtained according to the process of the present invention is preferably used in its manufactured shape and arranged in a plurality of combinations to form a filter medium assembly, but may be cut for shaping if necessary.

Incidentally, among the above-described physical characteristics, the following relationship was established as porosity [? (%)] Obtained from the molded body weight and the material resin density, and was used for evaluation in the examples to be described later.

<Porosity>

Porosity [ε (%)] = (V-T / ρ) / V × 100

Where V is the total volume of the molded body (m ³ ), T is the weight of the molded body (tons), and ρ is the density of the strand (material resin) (tons / m ³ ).

<Specific surface area>

Volume of strand alone in shaped body (V ₁ = T / ρ), and dividing it by the strand cross-sectional area (= ((d / 1000) ² x π ｘ 1/4)) calculated from the diameter of the strand (= d mm) gives the total strand length, From this, the specific surface area is calculated according to the following formula.

Total strand length: L (m) = V ₁ / ((d / 1000) ² × Π × 1/4)

Total strand surface area: S (m ² ) = Π × (d / 1000) × L

Specific surface area of strand: s (m ² / m ³ ) = S / V.

The filtration apparatus according to the present invention is formed by disposing at least two types of contact filter media molded bodies each formed in the above-described manner and having different strand thicknesses in a sewage treatment tank, and having a first paper arrangement comprising coarse resin strands on the upstream side. On the downstream side of the sewage treatment tank, a second species containing thin resin strands is disposed. 5 is a schematic cross-sectional view of a water treatment plant comprising filtration in accordance with a preferred embodiment of the present invention.

Referring to FIG. 5, a water treatment plant is formed by placing a sedimentation separation tank 60 downstream of a filtration device 50 according to a preferred embodiment of the present invention. The filtration device 50 is a filtration tank (wastewater treatment) having a space formed by the inlet porous plate 55 and the outlet porous plate 56 in height H, length L, and width W (not shown) dimensions. Jaw or chamber) 51. In the space of the filtration tank 50, the three kinds of contact filter medium molded bodies 52, 53, and 54 each composed of three kinds of thermoplastic resin strands 521, 531, and 541 each having a sequentially decreasing thickness are wastewater ( WW) is sequentially arranged from the upstream side to the downstream side along the flow direction AA. At the bottom of the filtration tank 51, the air distribution tube 57 extends in the width W direction at appropriate intervals in the length L direction.

During operation, sewage water (WW) including domestic drainage or factory wastewater is introduced into the upstream space of the inlet porous plate 55 and flows through the porous plate 55. Subsequently, the sewage (WW) flows through the contact filter medium formed bodies 52, 53, and 54 composed of three types of resin strands having a continuously decreasing thickness, during which the sewage (WW) is formed by the growth of water cotton and air distribution. Treatments such as cleavage of water cotton into fines (SS) by aeration with the tube 57 and decomposition into mud are performed. The final filtered water FW containing mud passes through the porous plate 56 and exits the filtration tank 51 as outflow water, which is introduced into the sedimentation separation tank 60, and the treated water CW is separated from the mud. And are discharged or reused as is or after further treatment, such as sterilization.

The number of types of filter medium molded bodies having different resin strand diameters from each other, the volume ratio (volume ratios) s therebetween, and the diameter ratio (diameter ratios) s therebetween depend on the BOD, SS, etc. in the treated wastewater, It may be appropriately designed in consideration of the required water quality improvement effect and the increase in the filtration pressure (water head difference). At least two kinds and a maximum of four kinds can be realistic. The volume ratio may be appropriate in the range of equal division ｘ (0.40 to 2.0) times, preferably equal division ｘ (0.7 to 1.5) times. The thickness ratio (circle equivalent diameter) between the resin strands forming the most upstream filter medium molded body and the most downstream filter medium molded body may be appropriately set to at least 1.5, preferably at least 2 and more preferably at least 3. The upper limit may be realistic up to 20, in particular up to 10. In the present invention, the dimensional change of the voids in the uppermost filter media molded body and the lowest filter media molded body in which the dimension of the suspended solids is remarkably caused due to the individual growth and cutting of the water cotton is very important. Thus, some degree of freedom is allowed with regard to the thickness of the strands forming the filter media molded body disposed at the intermediate position (s), so that, for example, the thickness relationship of the strands may be partially reversed.

[Yes]

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated further more concretely based on an Example and a comparative example.

(Example 1)

As a thermoplastic resin material, a filter material molded body was produced by using polyethylene (obtained as wire covering waste material) showing the following properties and using an apparatus system as shown in FIG. 1.

MFR value = 5.8 g / min (measured according to JIS-K7210 at a load of 190 ° C and 10 kgf)

Melting point = 110 ° C. and crystallization temperature = 97 ° C. (measured separately as temperature rise and fall rates of 10 ° C./min)

Density = 0.92 g / cm ³ .

The above-mentioned polyethylene is melt-kneaded in a single screw extruder 1 and has a spacing of about 15 mm each from the longitudinally and laterally adjacent nozzles, and in a zigzag arrangement as shown in FIG. 2, in the stationary die 1a. Extruded at 180 ° C. through a total of 21 nozzles of 3.3 mm diameter formed to form strand 3. The strand 3 is lowered, and the water 5a is discharged from the water spray cooler 5 which can adjust the spray amount while measuring the surface temperature by the non-contact surface thermometer 4 ("TH6200" manufactured by NEC San-A Co., Ltd.). It cools by spraying and controls surface temperature to 43 degreeC. Subsequently, while repeatedly moving the frame 7 in both directions of the X and Y axes at a constant speed of 3 m / min, the cooled strand 3 is servod such that the upper edge of the frame 7 is positioned 120 cm below the nozzle. The strands are placed on a horizontal biaxial movement device 6 with a motor and flow into the frame 7 with dimensions of 50 × 50 × 25 cm (X / Y / Z), thereby depositing the strands to a height of 25 cm. Let's do it. Details of the horizontal biaxial movement are similar to those described above, and the Y axis movement distance is 452 mm (middle X axis movement distance 84 mm) in the Y and -Y axis movement steps, and the X and -X axis movement steps are as follows. Where the X-axis movement distance is 423 mm (middle Y-axis movement distance 56 mm), first the strand extension direction change is included in the unit cycle of the 4-strand deposited layer formation period of Y-> X-> -Y-> -X, Regularly arranged strand deposits were obtained. The strand deposit is then fixed under a load of 10 kg (150 × 50 cm) applied by the top lid to provide a contact filter medium molded body having dimensions of 50 × 50 × 25 cm. The molded body consisted of substantially 21 strands and the length of one strand was calculated as about 65 m from the total weight of the molded body, the strand diameter and the number of strands (21).

(Example 2, Comparative Examples 1 and 2)

Same method as Example 1 except that the amount of water sprayed is changed to change the surface temperature of the strand flowing into the frame to 55 ° C (Example 2), 98 ° C (Comparative Example 1) and 22 ° C (Comparative Example 2). The contact filter medium compact was obtained.

The outline of the contact filter medium including the measured porosity obtained in the above examples and comparative examples are all shown in Table 1 below.

TABLE 1

<Note>

(Example 1) The joined portion of the strand was suitable for obtaining the desired porosity.

(Example 2) The joining portions of the strands were somewhat excessive to provide slightly lower porosity than desired.

(Comparative Example 1) The strands were joined together to provide much lower porosity than desired.

(Comparative Example 2) The strands failed to bond with each other, and failed to provide desirable low porosity.

(Example 3)

The nozzle 2 is changed to 44 nozzles each having a diameter of 1 mm, the surface temperature of the strand flowing into the frame 7 is changed to 42 ° C., and the Y-axis movement in the Y and -Y axis movement steps. First, the strand extension direction change is Y − with a distance of 449 mm (middle X-axis moving distance 86 mm) and an X-axis moving distance of 429 mm (middle Y-axis moving distance 56 mm) in the X and -X axis moving steps. A rectangular parallelepiped filter material molded body was produced in the same manner as in Example 1 except for using a regularly arranged strand deposit forming method comprising unit cycles of a four strand deposited layer forming period of> X-> -Y-> -X.

(Comparative Examples 3-1 and 3-2)

A rectangular parallelepiped filter material molded body was produced in the same manner as in Example 3, except that the strand surface temperatures flowing into the frame 7 were changed to 83 ° C. (Comparative Example 3-1) and 21 ° C. (Comparative Example 3-2). .

(Example 4)

A rectangular parallelepiped filter material molded body was produced in the same manner as in Example 1 except that the strand surface temperature flowing into the frame 7 was changed to 40 ° C.

(Comparative Examples 4-1 and 4-2)

A rectangular parallelepiped filter material molded body was produced in the same manner as in Example 4 except that the strand surface temperature flowing into the frame 7 was changed to 80 ° C. (Comparative Example 4-1) and 20 ° C. (Comparative Example 4-2). .

(Example 5)

The nozzle 2 was changed to eight nozzles each having a diameter of 5.5 mm, the Y-axis moving distance was 455 mm (middle X-axis moving distance 87 mm) in the Y and -Y axis moving steps, and X and -X In the axis movement step, first, the unit cycle of the four-strand sedimentation layer forming period, in which the change in the strand extension direction is Y-> X-> -Y-> -X, wherein the X-axis movement distance is 435 mm (middle Y-axis movement distance 57 mm). A rectangular parallelepiped filter material molded body was produced in the same manner as in Example 1 except for using a regularly arranged strand deposit formation method comprising a.

(Comparative Examples 5-1 and 5-2)

A rectangular parallelepiped filter material molded body was produced in the same manner as in Example 3, except that the strand surface temperatures flowing into the frame 7 were changed to 85 ° C (Comparative Example 5-1) and 18 ° C (Comparative Example 5-2). .

(Comparative Example 6)

Commercially available cement gravel binder ("Jarikko" manufactured by Aquatech Co., Ltd.); Bulk density: about 1000 kg / mm ³ , average dimension: about 100 mm, porosity: about 60%, specific surface area: 62m ² / m ³ ) was used as it is.

<< water treatment performance test >>

Each of the contact filter medium molded bodies provided in the above-described examples and comparative examples was packed in a small test chamber of 39L each measuring 2000 mm in length, 105 mm in width, and 250 mm in height (effective depth of 185 mm), and Comparative Example 6 Except for the water inlet surface was formed on the X-Ｙ plane. The sewage obtained after the initial sedimentation of the sewage treatment plant and with BOD = 160 mg / L, SS = 90 mg / L was then carried out at the bottom of the vessel with 20 vent tubes (each 0.8 in diameter) arranged at equal intervals along the length of the vessel. 40 holes per mm, provided), flowing air at a rate of 75 mL / min through a test bath at a rate of 25 L / min, including a 14-day pre-operation period and a 126-day experimental period. A water treatment experiment. During the experimental period, the effluent was received in a 20L settling separator with the discharge of surface water (treated water). The water quality of the effluent from the test tank was checked at a rate of once a week, and the BOD removal rate and SS removal rate were calculated as the average during the experiment period. In addition, the mud collected in the sedimentation separation tank was uniformly mixed at a rate of once every two weeks, and the mud weight was calculated from the capacity of the sedimentation separation tank and the SS concentration therein, whereby the mud generation rate was calculated according to the following equation.

Mud generation rate (%) = (mud accumulation + SS accumulation in treated water) / SS accumulation in feed water × 100,

Here, mud accumulation amount: accumulation amount of mud accumulated in the sedimentation tank and SS accumulation amount in the treated water: accumulation amount of SS in the finally treated water flowing out of the sedimentation separation tank.

Separately, to evaluate the flowability of the filter media, the water head difference between the inlet and outlet of the test bath was measured at the end of the experimental period.

The summary of the individual filter media of the previous and comparative examples and the water treatment performances evaluated are summarized in Table 2 below and shown in Table 2 below.

TABLE 2

<Note>

(Example 3) Although the water quality of the treated water was good and the mud generation rate was low, the water head difference (ΔP) was rather large.

(Comparative Example 3-1) On the tenth day after the start of the experiment, the hydrophobicity became poor, causing water to overflow from the container. Due to the blockage, ΔP became large, making the experiment impossible.

(Comparative Example 3-2) Both water flow and water quality improvement effects were not satisfactory.

(Example 4) Water flow was good and the incidence rate was low.

(Comparative Example 5-1) Two weeks after the start of the experiment, water flow became poor, causing water to overflow from the container. Due to the blockage, ΔP became large, making the experiment impossible.

(Comparative Example 5-2) Although water flowability was good, the water quality improvement effect was insufficient, and high mud generation rate was provided.

(Comparative Example 6) (Cement Gravel Binder) Both water flow and water quality improvement effects were quite good, but the weight was large.

(Example 6)

20L of sedimentation separation tank 60 is disposed downstream of the filtration device 50 composed of 39L small experimental filtration tanks filled with three kinds of filter medium molded bodies 52, 53, and 54 as shown in FIG. It is formed by. Filter material compacts 52, 53, 54, which consist of resin strands having diameters of 5.5 mm, 3.3 mm and 1 mm, respectively, are arranged in an equal volume ratio of 1/3 in sequence along the flow direction AA of sewage, respectively. The water receiving surface was formed on the individual XY surface. The filter medium molded bodies 52, 53, and 54 were the same as those provided in Examples 5, 4, and 3, respectively. As a result, the water treatment plant was used in the water treatment performance experiments described above for Examples 1-5 except that three filter media molded bodies were used instead of the single filter media molded bodies used in each of Examples 1-5. Same as

The same water treatment performance experiments as in Examples 1-5 were performed.

The evaluation results in the outline of the filter medium molded article used in this Example 6 and the water performance experiments are summarized in Table 3 below along with those of Examples 3 to 5 and Comparative Example 6.

[Table 3]

<Note>

(Example 6) The water quality improvement effect was excellent, the mud generation rate was low, and the water flowability was also very excellent.

As can be appreciated from the foregoing and the results shown in Tables 1 and 2 above, the present invention provides a contact filter medium and a contact filter medium production process that are light in weight and provide good water flow and water quality improvement effects. Further, by arranging a plurality of contact filter media such that the resin strand diameter embedded therein gradually decreases in the water treatment tank, it exhibits an excellent water quality improvement effect and a little increase in water filtration pressure, and has a high degree of contamination. Filtration devices are particularly suitable for various wastewaters, and also methods for treating sewage using filtration devices are provided.

Claims (16)

Extruding the hot melt thermoplastic resin into the strand form through a nozzle;
Dripping and depositing the strand into a frame having an opening having a predetermined horizontal shape,
The frame is moved horizontally in two dimensions with respect to the strands of the descending thermoplastic resin, and the falling strands are cooled to allow the strands to fall and deposit into the frame in a semi-solid state, thereby controlling porosity of 50 to 90%. A method for producing a contact filter medium molded article, which provides a final contact filter medium molded article having a shape. The method for producing a contact filter medium molded article according to claim 1, wherein the frame has a horizontal opening shape which is generally rectangular. The method for producing a contact filter medium molded body according to claim 1 or 2, wherein the horizontal two-dimensional moving direction of the frame with respect to the falling strand is an X-Y biaxial direction perpendicular to each other. 4. The contact filter medium molded body according to claim 3, wherein the contact filter medium molded body in the form of a laminate of deposited strands has a one strand deposition layer forming period in which the relative movement direction of the frame is generally along the X axis, and the relative movement direction of the frame is generally along the Y axis direction. A method for producing a contact filter medium molded article, which is formed in the frame by alternately repeating one strand deposition layer formation period. The method for producing a contact filter medium molded article according to any one of claims 1 to 4, wherein the plurality of nozzles are arranged in a zigzag shape or a circular radial shape. 6. The method of claim 1, wherein the flowing strand is cooled by causing a stream of mist water to act on the strand. 7. The method according to any one of claims 1 to 6, further comprising applying pressure to the strands deposited in the frame to improve adhesion between the strands. A contact filter medium molded article for sewage, comprising a melt-bonded strand laminate in the form of a solidified deposition product of a molten strand of thermoplastic resin, wherein a plurality of stacked strand horizontal layers are laminated in a vertical direction. 9. The method of claim 8 wherein the plurality of stacked strand horizontal layers comprises a first horizontal strand deposited layer comprising strands extending generally in the X-axis direction and a second extending strand extending in the Y-axis direction generally perpendicular to the X-axis direction. A contact filter medium molded body comprising a horizontal deposition layer, wherein the first and second strand deposition layers are alternately stacked in the vertical direction. The contact filter medium molded article for sewage according to claim 8 or 9, which has an overall shape having an overall rectangular parallelepiped shape. The contact filter medium molded article according to any one of claims 8 to 10, wherein the strand has a diameter of 0.5 to 10 mm, and the laminate has a porosity of 50 to 90%. With sewage treatment tank,
At least two types of contact filter medium molded bodies according to any one of claims 8 to 11, which are disposed in the sewage treatment tank,
The at least two kinds of contact filter medium molded bodies may include thermoplastic resin strands having different thicknesses from each other, and the first species including the thick resin strands may be disposed upstream and the second species comprising the thin resin strands may be disposed downstream of the sewage treatment tank. A filtration device for sewage disposed. 13. The filtration device for sewage according to claim 12, wherein each of the at least two kinds of contact filter medium shaped bodies each includes a strand of 0.5 to 10 mm, and has a porosity of 50 to 90% and a specific surface area of 50 to 500 m ² / m ³ . The filtration device for sewage according to claim 12 or 13, wherein the most upstream molded body and the most downstream molded body of the at least two kinds of contact filter medium molded bodies include thermoplastic resin strands providing a diameter ratio within a range of 1.5 to 20. A sewage treatment method using the filtration device according to any one of claims 12 to 14, comprising the step of allowing sewage to flow continuously through two or more of the contact filter medium molded bodies. The wastewater treatment method according to claim 15, wherein the effluent treated through the filtration device is introduced into the settling separation tank and the final surface liquid is discharged out of the settling separation tank.

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