JPH11156110A - Pressurizing filtration method and plastic made filter medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a pressurizing filtration method and plastic-made filter medium at a low installing cost, having a general use property, difficult to clog, and easily backwashed with a small amount of backwashing water by a method wherein a plastic-made elastic filtor medium of an appropriate shape, is filled in a filter cylinder, treating liquid is injected under an appropriate pressure, and backwashed under an ordinary pressure. SOLUTION: In a plastic-made chip-shaped filtor medium a fin wherein polyvinylchloirde having elasticity and its similar material are formed in many continuous wavy shape in a fan shape of about 10 to 15 ϕ mm outer diameter, about 15 to 75 mm height, above 0.5 to 2.0 mm thickness, and 40 deg. to 80 deg. angle, is arranged spirally around a central axis, a cylindrical clearance of about 5 to 20 mm diameter is provided along the central axis, and its appearance is in a suitable shape such as a cylindrical shape or a globular shape. By injecting continuously treating liquid at an appropriate and constant pressure, fins of chip-shaped filtration medium comes to have appropriate intervals, a straightened flow is generated on inside and outside faces and a surface of the fin, and adsorption of solid material is efficiently carried out. The backwashing can be easily executed since the fin interval is returned to an original state at ordinary pressure with elasticity of the filter medium to be widened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure (plastic tip filter material) capable of efficiently and inexpensively filtering a processing solution containing fine SS (suspended substance) even in a small amount, and a filtration method using the filter material. It is.

[0002]

2. Description of the Related Art Microstrainers and sand filters have been put into practical use as fine SS (suspension substance) separation equipment. However, they are suitable for treated water containing large amounts of SS (suspension substance). However, clogging of the separation element and the filter medium occurred in a very short time, and a large amount of backwash water was required for backwashing.

On the other hand, the sedimentation method and the pressure flotation method using power or buoyancy have disadvantages such as a large installation area of the apparatus, a long processing time, leakage of scum or sludge, and a low solids concentration ratio. (For example, “energy-saving inclined wedge wire screen”, Chemical Engineering, p4
5, 47, 1, '83).

[0004] Inclined plate filtration is widely used in water purification facilities and the like, but requires a large installation area and requires much labor for sludge treatment. However, it is necessary to separate coal and concentrate pulp raw materials. Wedge wire screens, which have been put to practical use mainly for the classification of coarse solids, have been used in energy-saving inclined wedge wire screens (Toray) for 100 μm.
m or less fine SS (suspended material) can be efficiently separated (JP-A-55-152511).

[0005]

However, wedge wire screens are also limited in their applications, their installation costs are quite high, and require maintenance and maintenance. They lack generality or versatility and are not suitable for small-scale filtration. Had.

[0006] The present invention develops a technique of a sloping plate or a wedge wire screen to provide a high-speed filtration (filtration method and filtration material) which is more versatile, has a low installation cost, has a simple structure, and has acid resistance and alkali resistance. It is something to offer.

[0007]

According to the first aspect of the present invention, an appropriate amount of a plastic filter medium having an appropriate shape and elasticity as described in the second and subsequent embodiments is used in an appropriate amount. Naturally, the filter tube is filled with the filter solution and the treatment liquid is continuously injected at an appropriate pressure and at a constant pressure, so that the fins of the chip-shaped filter material have an appropriate interval (0.0 mm).
(It is necessary to be about 5 to 0.1 mm), and rectification occurs on the inner and outer surfaces and the surface of the fin of the chip-shaped filter medium, and the same effect as a screen (cross flow filtration)
Is generated, and the solids are efficiently adsorbed mainly on the front and back surfaces of the fin.

[0008] In the backwashing, the fin spacing of the chip-shaped filter medium returns to normal pressure at normal pressure due to the elasticity of the filter material and is considerably wide (2 to 5 m).
m), fill the filter tube with backwash water, apply aeration or ultrasonic wave under normal pressure, remove the drain, and wash the backwash water at normal pressure to wash the solid material adhering to the surface of the filter media. It can be easily and effectively performed by injecting, and the amount of backwashing water used is extremely small, and the time required for backwashing is extremely short, although it depends on the shape of the chip-shaped filter medium.

According to the invention of claim 2, a plastic material such as polyvinyl chloride or polyvinylidene chloride which is resistant to acid and alkali and has elasticity has an outer diameter of 10 to 15 mm and a height of 15 mm as shown in FIG. ７５75 mm (the size depends on the required processing capacity), a large number of continuous wavy moderately rough surfaces having a thickness of 0.5 to 2.0 mm and an angle of 40 to 80 °. The fins are spirally arranged around the central axis, and have a diameter of 5 to 20 (m) along the central axis.
m) It is a chip-shaped filter medium having a columnar void and having a cylindrical or spherical external shape.

[0010] The chip-shaped filter medium is formed by cutting a cylindrical rod-shaped plastic having an appropriate diameter in an axial direction with a lathe or the like, changing the angle to the corrugated spiral band having the above-mentioned size, and then cutting and shaping the strip to a required dimension. It can be manufactured by bending and cutting in a wavy shape while heating after extruding a flat spiral band,
Since the fin surface requires an appropriate roughness, it is desirable to form the fin with a lathe.

The complete separation equation of the sedimentation velocity in the inclined plate type continuous sedimentation tank, which is a representative of the new filtration type, cross flow filtration, is η = v / (Q / S) η; separation efficiency S; separation area Q Flow rate v; settling velocity; theoretically, the separation efficiency is proportional to the separation area and inversely proportional to the flow rate. However, in the present invention, the effect of the flow rate is extremely small by taking the separation area very large as compared with the flow rate. We started R & D based on the judgment that it was possible to increase the efficiency.However, the separation efficiency and the washing efficiency of the adsorbed solids greatly depended on the fin spacing. It is necessary to increase the fin diameter.On the other hand, considering the cleaning efficiency at the time of backwashing, the fin interval should be widened, and in order to solve this, the refining force of the fin is used to filter the fin interval. A method of sometimes narrowing and widening at the time of backwashing, that is, a method of injecting the treatment liquid at a high pressure at the time of filtration and performing the treatment at a normal pressure at the time of backwashing, has been developed.

As for the filter material, plastic material, fin shape (thickness, shape and size of fin), fin interval, and tip shape (size, outer shape and size of central cavity of tip) are important. Because it greatly affects the separation efficiency, it was examined from the viewpoint of ease of processing, securing of separation area, securing of tap water for filtrate, and elastic repulsion of fins. As a result, the center part as shown in Fig. 2 was cylindrical. This led to the development of a chip-shaped filter medium in which the wavy fins spirally surround the central axis.

Since the ease of processing is directly reflected on the shape of the filter media itself, it can be cut or extruded by a lathe or the like, and can be heated, and the plastic material has a suitable elasticity. Is required.

Since the separation area directly affects the separation efficiency, it is necessary to maximize the separation area, that is, it is necessary to minimize the gap between chips as much as possible to maximize the separation area per chip. The area depends on the tip shape, especially the fin shape is important, and the wave depth affects the size of the separation area and affects the separation efficiency, while it is also related to the cleaning efficiency. Efficiency is improved but backwashing efficiency is reduced.On the other hand, if the depth is too shallow, separation efficiency will be deteriorated.In addition, the larger cavity will be used because the center cavity will be a water supply for the filtered treatment liquid that has passed between the fins. Good.

The elastic repulsion depends on the plastic material itself and the thickness of the fins, and is related to the injection pressure of the processing solution and the cleaning efficiency. If it is too large, it is necessary to increase the injection pressure in order to obtain an appropriate fin interval, which increases the flow rate and lowers the separation efficiency.

From the above facts, polyvinyl chloride, PVA, polystyrene and the like are listed as plastic filter media based on their use results (for example, water treatment engineering, 2nd edition,
P334), easiness of processing, repelling force of fins (hardness of plastic material itself), polyvinyl chloride and similar materials are optimal for material, spiral shape of tip filter material is optimal, and fin thickness is as shown in FIG. As shown in the figure, 0.5 mm or more and 2.0 mm or less are suitable, and in order to ensure the maximum separation area, it is necessary to increase the filling rate of the filtration tube and reduce the porosity for the same volume. We have devised a shaped or spherical tip-shaped filter medium and a corrugated fin having an angle of 40 degrees or more and 80 degrees or less with respect to the axis.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A test apparatus (processing liquid tank, liquid transfer variable pump, filter tube containing a chip-shaped filter medium (injected from the upper part of the filter cylinder and drained from the lower part)) configured as shown in FIG. Connect the liquid tank with a pressure-resistant hose and circulate)
Then, a fixed amount of treated water having a known turbidity or concentration was charged into the treatment liquid tank, a variable pump was adjusted, the liquid was sent to the filter cylinder at the required pressure, and again circulated back to the treatment liquid tank.

[0018]

EXAMPLE 1 kg of the plastic filter material shown in FIG. 1 was stored in a filter tube of a filter facility as shown in FIG. 1, the filter tube was filled without gaps, and 50 liters of domestic wastewater (bath water) was collected in a treatment liquid tank. The flow rate of the liquid transfer variable pump was set to 5 l / min and 15 l / mim, and filtration was performed. A required amount of test treatment liquid was collected from the treatment liquid tank every hour, and the turbidity of each sample was measured and compared. As a result, as shown in Table 1, the separation efficiency was improved on average by about 250% in the case of pressurization as compared with the case of no pressurization.

[Table 1]

The present invention is configured as described above and has the following effects. It can be used in various places and locations and is versatile. Clogging is difficult to occur. It can be easily backwashed with a small amount of backwash water. It can handle from small to large filtration. Installation cost is extremely low. The installation area is extremely small. Maintenance is easy.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a filtration device.

FIG. 2 is a sketch drawing of a plastic chip filter material.

Claims (2)

[Claims] 1. A filtration method comprising storing a plastic filter material having an appropriate shape and elasticity in a filter tube, injecting a treatment liquid at an appropriate pressure, injecting backwash water, and backwashing at normal pressure. 2. An elastic cylindrical or spherical shape, wherein a plurality of continuous wave-shaped fins having an angle of a fan-shaped portion of 40 ° or more and 80 ° or less are radially and spirally mounted around a central axis. Shaped plastic tip filter media.