JP7266912B1 - Ozone treatment device and treatment liquid purification system - Google Patents

Abstract

An object of the present invention is to provide an apparatus for cleaning the liquid to be treated by removing suspended matter in the liquid to be treated with high probability. An ozonizer (3) for solving the above problems includes an outer cylinder (41), an inner cylinder (42) provided inside the outer cylinder (41), and a gap (GP) between the outer cylinder (41) and the inner cylinder (42). an ozone supply port 44 for supplying ozone OZ; a discharge port 53 for the scum SC, a discharge port 45 for the sediment PS provided at the bottom of the outer cylinder 41, and a discharge port 46 for the ozonated liquid TS provided at the bottom of the inner cylinder 42. . [Selection drawing] Fig. 1

Description

The present invention relates to an ozone treatment apparatus for treating a liquid to be treated with ozone. At the same time, the present invention relates to a liquid purification system including the ozone treatment device.

In various factories and the like, a large amount of waste liquid is generated by washing objects to be washed, and it is desired to effectively utilize this waste liquid. For example, washing waste plastic at a waste plastic recycling plant, washing rice before cooking it at a food factory that manufactures boxed lunches, and washing clothes at a laundry factory generate a large amount of liquid waste. Effective utilization of waste liquid is a challenge.

In recent years, efforts to recycle waste plastics have attracted attention in connection with the recent focus on Sustainable Development Goals (SDGs). In addition, waste plastic recycling plants generate a large amount of waste liquid during cleaning, so the importance of effective utilization is increasing.

According to the 2019 Plastic Product Production, Disposal, Recycling, and Processing and Disposal Status Report (published in December 2020) issued by the Japan Plastic Recycling Association, it occurs in Japan. It is said that 8.5 million tons/year of waste plastics are produced, of which 1.86 million tons/year are material-recycled, and the rest are incinerated for thermal recycling or landfill disposal. It is expected that the amount of waste plastic that is recycled as a material will increase in the future as the idea of SDGs permeates society and the momentum to prevent the outflow of microplastics into the sea increases.

By the way, in the aforementioned material recycling, it is necessary to return waste plastics to homogeneous plastic raw materials. The general process of material recycling of this waste plastic is (A) crushing, (B) sorting, (C) crushing, (D) dry cleaning, (E (F) dehydration; (G) dry flakes; (H) heat extruder processing; and (I) pellets (raw material for injection molding machine). Through these processes, it is recycled into a high-quality plastic raw material. In the above-described step (E), water is used to wash the waste plastic to remove contaminants adhering to the waste plastic, and a large amount of waste liquid is generated in this washing step.

The present invention relates to an apparatus for purifying a liquid to be treated (for example, the waste liquid described above), and related prior art includes the invention disclosed in Patent Document 1 below.

Patent Document 1 discloses an ozone addition device that adds 1 to 120 g-O ₃ /m ³ of ozone to water to be treated containing algae, and a sedimentation tank that coagulates and sediments algae contained in the water to be treated to which ozone has been added. This invention relates to an algae separation system comprising According to this patent document 1, it is supposed that the sedimentation property at the time of sedimentation-separation of algae can be improved.

JP 2018-158315 A

Patent Document 1 discloses an ozone adding device for adding ozone to water to be treated containing algae and a sedimentation tank for coagulating and sedimenting algae contained in the water to be treated to which ozone has been added. No structural details are provided. That is, nothing has been clarified about the structure of the sedimentation tank for increasing the efficiency of flocculation and sedimentation of algae.

In addition, the algae classification system of Patent Document 1 is a system specialized for sedimentation and separation of "algae", and it is also clear how to remove suspended matter other than "algae". It has not been.

For example, in the above-mentioned waste plastic recycling plant, the liquid to be treated often contains organic matter different from algae. For example, food residue (organic matter) often adheres to the plastic used for food packaging, so food residue is often contained in waste liquid (liquid to be treated) of waste plastic recycling plants. . In addition, waste liquid (liquid to be treated) in a cleaning factory often contains sebum (organic matter) of the wearer adhering to clothes. In addition, the waste liquid from each factory often contains inorganic compounds such as detergents used for cleaning.

As described above, various suspended substances are contained in the liquid to be treated, and there is a demand for an apparatus that removes these with a high probability and cleans the liquid to be treated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide an apparatus for cleaning the liquid to be treated by removing suspended matter in the liquid to be treated with high probability.

The present invention, which has solved the above problems, is as follows.
(First aspect)
an outer cylinder;
an inner cylinder provided inside the outer cylinder;
an ozone supply port for supplying ozone to the gap between the outer cylinder and the inner cylinder;
a to-be-processed liquid supply port for supplying the to-be-processed liquid to the gap between the outer cylinder and the inner cylinder;
a scum discharge port provided at the top of the outer cylinder;
a discharge port for precipitated substances provided at the bottom of the outer cylinder;
an ozonated liquid outlet provided at the bottom of the inner cylinder;
An ozonation apparatus characterized by comprising:

(Effect)
In the ozone treatment apparatus of the first aspect, the liquid to be treated and ozone are supplied to the gap between the outer cylinder and the inner cylinder. Suspended matter contained in the liquid to be treated that has a high specific gravity precipitates in the lower portion of the outer cylinder and is discharged from the discharge port for the precipitated matter provided in the corresponding lower portion. On the other hand, among the suspended substances contained in the liquid to be treated, those having a low specific gravity float together with the ozone in the gap between the outer cylinder and the inner cylinder, and stay around the upper surface of the liquid to be treated in the ozonizer. . Suspended solids remaining on the upper surface are discharged from a scum discharge port provided in the upper portion of the outer cylinder. The liquid, which has been cleaned by removing many suspended solids from the liquid to be treated in this way, moves from above the gap between the outer cylinder and the inner cylinder to the upper part of the inner cylinder, and then moves to the inside of the inner cylinder. It moves downward inside and is then discharged as an ozonated liquid from a discharge port provided at the bottom of the inner cylinder.

Note that many organic substances contained in the liquid to be treated are decomposed by ozone and discharged from the scum discharge port and the precipitated substance discharge port. Microorganisms such as bacteria contained in the liquid to be treated are eliminated (bacteriolyzed) by ozone. Further, odorous substances (for example, volatile organic compounds (abbreviated as VOCs)) contained in the liquid to be treated are also destroyed by ozone and deodorized and deodorized.

As described above, even if the liquid to be treated contains organic matter, microorganisms, odorous substances, etc., the ozone is removed during the process of moving inside the ozonizer (the gap between the outer cylinder and the inner cylinder and the inside of the inner cylinder). Since the ozonated liquid is treated, the ozonated liquid discharged from the ozonator can contain less organic matter, less live microorganisms, and less undestroyed odorous substances.

In addition, since the ozonization apparatus of the first aspect has the outer cylinder and the inner cylinder, the movement distance of the liquid to be treated moving inside the ozonation apparatus can be increased as compared with the ozonization apparatus having only the outer cylinder. can be done. As a result, the contact time between the liquid to be treated and ozone can be lengthened, and the ozone treatment (for example, decomposition of organic substances, sterilization of microorganisms, and destruction of odorants) can be sufficiently performed. It should be noted that even with an ozonation apparatus consisting only of an outer cylinder, it may be possible to increase the moving distance of the liquid to be treated moving inside the ozonation apparatus by enlarging the size of the ozonation apparatus itself. According to the first aspect, it is advantageous in that the moving distance of the liquid to be treated can be increased without increasing the size of the ozone treatment apparatus. When the size of the ozone treatment apparatus becomes large, various disadvantages arise such as an increase in initial cost, difficulty in securing an installation site, and an increase in maintenance labor.

In addition, since ozonation and removal of suspended solids can be performed simultaneously inside the ozonator, the initial cost can be reduced and the installation space can be secured compared to installing an ozonator and a suspended solids remover separately. There are various advantages such as ease of installation and reduction of maintenance labor.

(Second aspect)
The ozone treatment apparatus according to the first aspect, wherein the ozone supply port is an ozone microbubble nozzle that supplies ozone microbubbles.

(Effect)
In the ozone treatment apparatus according to the second aspect, ozone microbubbles are supplied to the inside of the ozone treatment apparatus. By supplying ozone in the form of ozone microbubbles, it becomes easier for ozone to capture suspended solids in the liquid to be treated. It is discharged from the scum discharge port provided in the. In addition, since the chances of contact between microorganisms and odorous substances in the liquid to be treated and ozone increase, sterilization (bacteriolysis) of microorganisms and decomposition of odorous substances progress, and a cleaner ozonized liquid can be obtained.

(Third aspect)
The ozone treatment apparatus according to the first aspect or the second aspect, wherein the ozone supply port is provided at the lower portion of the outer cylinder.

(Effect)
In the third mode, the ozone supply port is provided at the bottom of the outer cylinder. By supplying ozone from the lower part of the outer cylinder, it is possible to create an upward flow of ozone in the gap between the outer cylinder and the inner cylinder. As a result, compared to the case where the ozone supply port is provided at the top of the outer cylinder, for example, the chances of contact between the suspended solids in the liquid to be treated and the ozone increase, so more suspended solids in the liquid to be treated rise to the surface. and many of the floating suspended solids can be removed as scum.

(Fourth aspect)
The to-be-processed liquid supply port is provided at the bottom of the outer cylinder,
The ozone processing apparatus according to any one of the first to third aspects, wherein the liquid to be treated supply port is directed in the circumferential direction of the outer cylinder.

(Effect)
In the fourth aspect, the to-be-processed liquid supply port is provided in the lower portion of the outer cylinder. By providing the to-be-processed liquid supply port in the lower part of the outer cylinder, the residence time of the to-be-processed liquid can be lengthened compared with the case where it is provided in the upper part or the middle part of the outer cylinder.

In addition, in the fourth aspect, the to-be-processed liquid supply port is directed in the circumferential direction of the outer cylinder. When the liquid-to-be-processed supply port is directed in the circumferential direction of the outer cylinder, the liquid-to-be-processed supplied from the liquid-to-be-processed supply port rises gradually while swirling in the gap between the outer cylinder and the inner cylinder. The residence time of the treatment liquid can be lengthened.

As described above, the fourth aspect is characterized in that the residence time of the liquid to be treated can be lengthened. As the retention time of the liquid to be treated increases, the contact time between the liquid to be treated and ozone increases, so that the ozone treatment progresses and a cleaner ozone-treated liquid can be obtained.

(Fifth aspect)
A liquid purification system having the ozone treatment apparatus according to any one of the first to fourth aspects,
Having a filtration device for filtering the ozonated liquid to generate a filtrate in the latter stage of the ozonation device,
The filtering device is
a filtration vessel having a supply port for the ozonated liquid and a discharge port for the filtrate;
a pleated filter provided inside the filtration container, having an outer surface serving as a filtration surface and an interior serving as a passage for the filtrate, and formed into a tubular shape while forming a plurality of pleats by folding a flat filter medium into a bellows shape; having
A system for purifying a liquid to be treated, characterized by:

(Effect)
The to-be-processed liquid purification system of the fifth aspect is provided with a filtration device in the latter stage of the ozone treatment device. This filtering device has a pleated filter formed in a cylindrical shape while forming a plurality of pleats by folding a flat filter material into a bellows shape.

A filtration device is provided after the ozonation device, and when the ozonated liquid is filtered by this filtration device, most of the suspended solids in the ozonated liquid are captured by this filter, resulting in a clean process with very few suspended solids. A treated liquid (filtrate) can be obtained.

In addition, when a pleated filter formed in a tubular shape is used while a flat filter medium is folded into a bellows shape to form a plurality of pleats as in this aspect, a flat filter in which a flat filter medium is simply formed in a tubular shape is used. More ozonated liquid can be filtered and more clean liquid can be obtained in less time than otherwise.

(Sixth aspect)
The to-be-processed liquid purification system according to the fifth aspect, which has a flocculant addition path for adding a flocculant to the to-be-processed liquid.

(Effect)
The to-be-processed liquid purification system of the sixth aspect has a flocculant addition route for adding a flocculant to the to-be-processed liquid. When a flocculant is added to the liquid to be treated, suspended matter in the liquid to be treated aggregates and increases in specific gravity. It becomes easy to be discharged as a sediment from the outlet. In addition, even suspended solids (coagulated suspended solids) whose specific gravity is not that heavy are easily captured by ozone, so they float together with the ozone and scum from the discharge port provided at the top of the ozonizer. It is easy to be discharged as Furthermore, even suspended matter that has not been removed as sediment or scum in the ozonizer is agglomerated to some extent by the coagulant, so it is likely to be captured by the filter of the filtration device provided in the subsequent stage. As a result, more suspended solids in the liquid to be treated can be removed than when no coagulant is added, resulting in a cleaner treated liquid (filtrate) with very few suspended solids. Obtainable.

According to the present invention, suspended matter in the liquid to be treated can be removed with high probability, and the liquid to be treated can be cleaned.

1 is a front view of an ozone processing apparatus according to the present invention; FIG. 2 is a cross-sectional view taken along line XX' of FIG. 1; FIG. 1 is a filtering device of a system for purifying a liquid to be treated according to the present invention; (A) is a front view, and (B) is a plan view, omitting the display of the pleat filter. It is explanatory drawing of the pleat filter of a filtering apparatus. It is a to-be-processed liquid purification system which concerns on this invention.

Preferred embodiments of the present invention will be described below with reference to the drawings. The following description and drawings merely show one embodiment of the present invention, and should not be construed as limiting the content of the present invention to this embodiment.

(Liquid to be processed TL)
A liquid to be treated TL is supplied to the ozone treatment device 3 . This liquid to be treated TL is not particularly limited, but for example, waste liquid generated when washing plastics in a plastic recycling factory, waste liquid generated when washing rice etc. in a food factory, waste liquid generated in a cleaning factory Drainage generated when clothes are washed can be mentioned. Effluents from plastic recycling plants contain substances adhering to waste plastics (food residue, oil, etc. in the case of food trays), microplastics that are finely crushed waste plastics, detergents used for cleaning, etc. There are many. In addition, waste liquids from food factories often contain food residues, microorganisms adhering to food, washing liquids, residues of food additives, and the like. In addition, the waste liquid from the cleaning factory contains sebum and foreign matter adhering to clothes, clothes fibers (including microplastics if the clothes are made of chemical fibers), detergents (microplastics depending on the type of detergent). including ) and so on are often included.

(Ozone treatment device 3)
1 and 2 show an embodiment of an ozone treatment apparatus 3 according to the present invention. This ozone processing device 3 has an outer cylinder 41 and an inner cylinder 42 , and the inner cylinder 42 is provided inside the outer cylinder 41 . 1 and 2, the upper and middle portions of the outer cylinder 41 and the inner cylinder 42 are cylindrical, but the shape of the outer cylinder 41 and the inner cylinder 42 is not limited to a cylindrical shape. For example, it may be changed to an arbitrary shape such as a cylinder with a triangular, quadrangular, or pentagonal cross section, or a cylinder with an elliptical cross section. 1 and 2, the outer cylinder 41 and the inner cylinder 42 have the same shape (cylindrical). may have different shapes.

Further, as shown in FIGS. 1 and 2, the lower portions of the outer cylinder 41 and the inner cylinder 42 are preferably shaped like an inverted cone like a funnel or an inverted pyramid. By forming the outer cylinder 41 into an inverted conical shape or an inverted pyramidal shape, the precipitated materials PS are easily collected at the lower end of the outer cylinder 41, and the precipitated materials PS are discharged from the precipitated material discharge port 45 provided at the lower end of the outer cylinder 41. Easier to eject. Further, by forming the inner cylinder 42 into an inverted cone shape or an inverted pyramid shape, a small amount of suspended matter contained in the ozonated liquid TS is likely to gather at the lower end of the inner cylinder 42. The suspended matter can be easily discharged from the treated liquid discharge port 46 .

After rising through the gap GP between the outer cylinder 41 and the inner cylinder 42 , the liquid to be treated TL climbs over the upper end of the inner cylinder 42 and moves into the inner part IN of the inner cylinder 42 . Therefore, it is preferable to make the upper end of the inner cylinder 42 lower than the upper end of the outer cylinder 41 . Specifically, the distance Z between the upper end of the outer cylinder 41 and the upper end of the inner cylinder 42 is preferably 250 mm or more, more preferably 300 mm or more.

Using the space of the gap GP between the outer cylinder 41 and the inner cylinder 42, the heavy suspended solids contained in the liquid TL to be processed are precipitated, and the precipitated suspended solids are discharged as the precipitate PS, and the liquid to be processed is discharged. Light suspended matter contained in the TL is floated, and the floated suspended matter is discharged as scum SC. In order to classify the suspended solids contained in the liquid to be treated TL by weight and remove as many suspended solids as possible, it is preferable to secure a gap GP of a certain size. Specifically, the ratio of the volume of the gap GP between the outer cylinder 41 and the inner cylinder 42 to the volume of the inner part IN of the inner cylinder 42 is preferably about 1:1. This volume ratio is the ratio of the spaces below the upper end of the inner cylinder 42 as a reference.

Also, as shown in FIGS. 1 and 2, it is preferable to provide a raking device 47 above the ozone treatment device 3 . The illustrated raking device 47 is attached to a circular top plate 3T that covers the upper opening of the outer cylinder 41. A shaft portion 47A extending downward from the center of the top plate 3T and a shaft portion It has a blade portion 47B extending laterally from 47A. It is preferable to extend the blade portion 47B to the vicinity of the inner wall of the outer cylinder 41 . A motor (not shown) is attached to the shaft portion 47A, and when the shaft portion 47A is rotated by this motor, the blade portion 47B is also opened. The blade portion 47B is preferably in contact with the liquid surface LI of the liquid to be treated TL existing inside the ozone treatment device 3, and the rotation of the blade portion 47B scrapes the scum SC accumulated near the liquid surface LI. sent. The collected scum SC is guided to a scum recovery section 52 provided outside the outer cylinder 41, discharged from a scum discharge port 53 provided in the scum recovery section 52, and then conveyed to the dewatering device 18. . The properties of the scum SC collected by the scum collection unit 52 are periodically checked, and if it is determined that the scum SC mainly consists of oil, the scum collection unit 52 is removed, carried out, and disposed of as industrial waste. It may be configured to

In order to sufficiently classify the suspended solids contained in the liquid TL to be processed and to increase the contact time between the suspended solids contained in the liquid TL to be processed and ozone, the supply port 43 of the liquid to be processed TL is provided as an outer cylinder. It is preferably provided below 41 . In the embodiment of FIG. 1, a supply port 43 is provided near the boundary between the cylindrical portion and the inverted conical portion of the outer cylinder 41 . The position where the supply port 43 for the liquid to be processed TL is provided is not limited to the illustrated embodiment, and may be provided above US in FIG. 1 or may be provided below DS.

Moreover, it is preferable to orient the supply port 43 of the liquid to be treated TL in the circumferential direction of the outer cylinder. In the embodiment of FIG. 1, the supply port 43 is oriented along the inner peripheral wall of the outer cylinder 41 . By orienting the supply port 43 in the circumferential direction of the outer cylinder 41 in this manner, the liquid to be treated TL supplied from the supply port 43 is rotated in the circumferential direction in the gap GP between the outer cylinder 41 and the inner cylinder 42 . move to By swirling the liquid TL to be processed, the time for which the supplied liquid TL to be processed stays in the gap GP can be increased, so that the suspended matter contained in the liquid to be processed TL can be sufficiently classified. In addition, the contact time between the suspended solids contained in the liquid to be treated TL and ozone can be increased.

In addition, it is preferable that the liquid to be treated TL rises spirally while turning in the gap GP between the outer cylinder 41 and the inner cylinder 42 in the circumferential direction. Therefore, it is preferable to orient the supply port 43 in the circumferential direction of the outer cylinder 41 and slightly upward US.

As described above, when the contact time between the suspended solids contained in the liquid to be treated TL and the ozone increases, the suspended solids are captured by the ozone and easily rise to the surface. As a result, suspended solids in the treatment liquid TL can be reduced. In particular, when the suspended solids are organic substances, the amount of organic substances that are destroyed by ozone and become smaller increases, so the amount of organic substances that float increases, and as a result, the amount of organic substances in the treatment liquid TL can be reduced. Moreover, when the suspended matter is microorganisms, the chances of contact between ozone and microorganisms increase, so many microorganisms can be sterilized (bacteriolyzed). When the microorganisms are eliminated (bacteriolysis), it is possible to suppress the generation of offensive odors caused by the microorganisms. In addition to sterilizing (bacteriolyzing) microorganisms in the liquid to be treated TL, ozone can also purify the inside of each device and each pipe that constitutes the system 100 . Furthermore, when the suspended solids are odorous substances, the chances of contact between ozone and odorous substances increase, so that the destruction of the odorous substances can be promoted further, and the generation of malodor from the treatment liquid TL can be prevented.

The ozone supply port 44 for supplying ozone is also preferably provided in the lower portion of the outer cylinder 41 for the same reason as the to-be-processed liquid supply port TL. In the embodiment of FIG. 1, the supply port 43 is provided in the vicinity of the boundary between the cylindrical portion and the inverted conical portion of the outer cylinder 41. It may be provided in the US, or may be provided in the lower DS. In addition, in the embodiment of FIG. 1, the ozone supply port 44 is attached to the outer cylinder 41, but it is not limited to this form. You may change to arbitrary forms, such as hanging from.

As the ozone supply port 44, an ozone microbubble nozzle that generates ozone microbubbles is preferably used. The average particle size of the ozone microbubbles supplied from the ozone microbubble nozzle is preferably 150 μm or less, more preferably 80 μm or less. If the average particle diameter is larger than 150 μm, the speed at which the ozone microbubbles float is high, so the contact time between the suspended solids contained in the liquid to be treated TL and ozone cannot be sufficiently secured, and the ozone treatment may be insufficient. be. In order to enhance the ozone treatment effect, the smaller the average particle size of the ozone microbubbles, the better. According to the performance of valves currently on the market, the average particle size can be as small as 10-20 μm. Although the average particle size of the ozone microbubbles is as described above, it is preferable that the ozone microbubbles contain many particles having a particle size of about 50 to 100 μm. Such ozone microbubbles having a particle size of about 50 to 100 μm have the advantage of being highly effective in floating suspended solids contained in the liquid TL to be treated.

The particle size and average particle size of ozone microbubbles can be measured by known methods such as an image analysis method and a laser diffraction method. Specifically, it can be measured based on a calculation method published in a catalog of a commercially available microbubble particle size measuring device.

Further, it is preferable to provide a liquid level sensor 49 inside the ozone treatment apparatus 3 for detecting the position of the liquid level of the liquid TL to be treated existing in the ozone treatment apparatus 3 . Then, it is preferable to adjust the amount of the liquid to be treated TL supplied into the ozone treatment apparatus 3 based on the detection result of the liquid level sensor 49 . Specifically, the liquid level LI of the liquid to be treated TL existing in the ozone treatment apparatus 3 is positioned higher than the upper end of the inner cylinder 42 and lower than the upper end of the outer cylinder 41 . It is preferable to More preferably, the position of the blade portion 47B of the raking device 47 and the position of the liquid surface LI of the liquid to be treated TL existing in the ozone treatment device 3 are preferably overlapped.

As described above, the liquid to be treated TL from which the suspended solids have been removed while flowing through the gap GP between the outer cylinder 41 and the inner cylinder 42 passes over the upper end of the inner cylinder 42 from the upper part of the gap GP and enters. After flowing into the inner IN of the cylinder 42 and moving downward in the inner IN of the inner cylinder 42, it is discharged from the treating liquid outlet 46 as the ozonated liquid TS. Since the ozonated liquid TS may contain suspended matter (for example, microplastics) that could not be removed by the ozonizer 3, a filter 4 is provided after the ozonator 3. , preferably to remove its suspended matter. Specifically, the ozone treatment device 3 is mainly suitable for removing relatively light oils and the like contained in the liquid to be treated TL, and the filtering device 4 in the latter stage is suitable for removing other suspended matter and organic particles. Are suitable. By providing this ozone processing device 3, it is possible to prevent clogging of the filter 12 of the filtering device 4 in the latter stage. In addition, since colloidal particles can be aggregated in the ozone treatment device 3, there is also the advantage that suspended matter (for example, aggregated colloidal particles) can be easily removed by the filtering device 4 in the subsequent stage. In addition, since organic matter that inhibits aggregation is decomposed by ozone in the ozone treatment device 3, there is an advantage that colloidal particles are easily aggregated in the ozone treatment device 3.

(Filtration device 4)
An embodiment of the filtering device 4 is shown in FIGS. The filtering device 4 is one device that constitutes the liquid purification system 100 to be treated. The ozonated liquid TS that has been ozonized by the ozonizer 3 is supplied to the filter 4 . This filtering device 4 removes fine suspended matter in the ozone-treated liquid TS, and the purified liquid is discharged to the outside as a filtrate.

The illustrated filtration device 4 is a dead end filtration (dead-end filtration) type device in which the ozonated liquid TS is filtered by a filtration filter 12 in a closed filtration container 11 and the filtrate B is discharged.

Specifically, the filtration device 4 includes a filtration container 11 that houses a filtration filter 12 . A cake discharge chute 11S is provided in the lower portion of the filtration container 11, and a cylindrical filter built-in portion 11U is continuous above the cake discharge chute 11S. The shape of the filtration container 11 is not limited to the above-described shape, and may be changed to any shape such as a shape without the cake discharge chute 11S.

Inside the filtration container 11, a cylindrical body 12s having a permeation hole for the filtrate B formed on the wall surface and a filtrate passage 12r formed therein is provided. The one shown in the figure is cylindrical, and is arranged in the filtration container 11 with its central axis extending along the vertical direction of the filtration container 11 . The shape and posture of the tubular body 12s are not particularly limited, and the shape of the tubular body 12s may be changed to any known shape such as a square tube. You may install in the filtration container 11 so that a central axis may become a horizontal direction. The illustrated cylindrical body 12s is formed by molding a flat plate made of punching metal or the like having a permeation hole into a cylindrical shape, and the space inside the cylindrical body 12s serves as a filtrate passage 12r.

A filtration membrane 12m is provided outside the wall surface of the cylindrical body 12s. As the filtration membrane 12m, since the surface area (filtration area) is large, a flat filter material is folded in a zigzag (accordion shape) and wrapped around the outer peripheral surface of the cylindrical body 12s to form a cylindrical pleated filter. It is preferable to use By using a pleated filter, the surface area of the filter is increased as compared with a simple flat filtration filter in which the filter material is not folded, so that the processing capacity of the ozonated liquid TS per unit time can be significantly increased. In order to remove as many suspended solids in the ozonated liquid TS as possible, it is necessary to reduce the speed at which the ozonated liquid TS passes through the filtration filter 12 as much as possible. tends to decrease. However, even in such a case, by using a pleated filter instead of a flat filter, it is possible to prevent the inconvenience of reducing the amount of the ozonated liquid TS to be filtered.

A plurality of folds can be formed by folding the filter medium in a zigzag manner as described above. This pleated filter has the advantage that the cake K can be easily peeled off and discharged because the distance between the wall surfaces of adjacent folds gradually widens from the inside to the outside. In addition, the length L1 between the tips of adjacent folds can be set to 6 mm, for example, and the length L2 from the tip to the base of the fold can be set to 100 mm, for example.

Filtration membrane 12m can be a single layer or multiple layers. As the material (filter material) of the filtration membrane 12m, for example, polytetrafluoroethylene (also known as "Teflon" (registered trademark)), polyester, polyphenylene sulfide (PPS) resin, nylon, stainless steel, or the like can be used. In particular, it is preferable to use the filter membrane 12m whose surface is laminated with polytetrafluoroethylene. By laminating with polytetrafluoroethylene, the adherence of deposits adhering to the surface of the filtration membrane 12m becomes poor, so the deposits can be easily peeled off. However, since polytetrafluoroethylene is hydrophobic, if polytetrafluoroethylene is used as it is, it is difficult to filter the ozonated water when the ozonated liquid TS is water. Therefore, it is preferable to chemically treat the polytetrafluoroethylene to make the surface of the filtration membrane 12m hydrophilic. By subjecting polytetrafluoroethylene to a chemical treatment to make the surface of the filtration membrane 12m hydrophilic, it becomes a filter that easily removes deposits adhering to the surface of the filtration membrane 12m and that easily allows ozonated water to pass through. can do. In this way, it becomes easier to remove the deposits attached to the surface of the filtration membrane 12m, so when cleaning the filtration membrane 12m, the undiluted solution (liquid to be treated TL or ozone treated liquid TS) is simply sprayed onto the filtration membrane 12m. There is an advantage that deposits can be removed with

The film thickness of the filtration membrane 12m is preferably 0.3 mm to 0.7 mm, more preferably 0.6 mm. Further, the fiber diameter of the filter medium (meaning projected area circle equivalent diameter, Heywood diameter; hereinafter the same) is preferably 0.1 μm to 3 μm, more preferably 0.1 μm. If fibers with a fiber diameter of less than 0.1 μm are used, the resistance during filtration will increase and the apparent surface area will become narrower. Also, if fibers with a fiber diameter larger than 3 μm are used, suspended particles will permeate through the gaps between the fibers of the filtration membrane 12m. Therefore, it is preferable to form the filtration membrane 12m having a certain degree of coarseness by using a filter medium having a fiber diameter of 0.1 μm to 3 μm. With such a filtration membrane 12m, suspended particles in the ozonated liquid TS adhering to the surface of the filtration membrane 12m during filtration act as a filtration layer. The length of the filtration membrane 12m in the longitudinal direction can be, for example, 300 mm to 2000 mm.

In this embodiment, the surface 12f of the filtration membrane 12m refers to the surface facing the filtration container 11 and the surface in contact with the ozonated liquid A. As shown in FIG. On the other hand, the rear surface 12b of the filtration membrane 12m refers to the surface facing the cylindrical body 12s and the surface in contact with the filtrate B. As shown in FIG.

In addition, since the cleaning liquid C is sprayed onto the surface 12f of the filtration membrane 12m, it is possible to use the filtration membrane 12m having a predetermined strength or more so that the filtration membrane 12m is not damaged by the shock wave of the liquid C sprayed. preferable. For example, in the measuring method of JIS L-1906, tensile strength (N/5 cm) vertical: 1200, horizontal: 700, bursting strength (kgf/cm ² ) vertical: 25 is preferably used.

A support plate (filter support 29) made by zigzag-folding a honeycomb mesh or a wire mesh along the shape of the folds (so as to be in contact with the back surface 12b of the filter membrane 12m) is preferably arranged on the inner surface of the folds. As the cake K is layered on the surface 12f of the filtration membrane 12m, the folds of the pleated filter are crushed, and there is a possibility that the space in the folds will be "blocked". can be prevented.

By using the filtering device 4 as described above, minute suspended matter contained in the ozonated liquid TS can be removed. In particular, even if the ozonation liquid TS contains microplastics, it is possible to remove the microplastics.

In addition, it is preferable to periodically check the quality of the filtrate B discharged from the filtering device 4 . Then, when VOCs, heavy metal ions, and high-concentration normal-hexane extract substances are detected from the filtrate B, the filtration by the filtration device 4 is temporarily stopped, and after washing the filtration membrane 12m, the adsorbent supply device 22 and the filtration device Preferably, 4 is supplied with adsorbent.

Although the adsorbent is not particularly limited, activated carbon, zeolite, silica, alumina, titania, titanium oxide, imogolite and the like can be used, for example. Examples of raw materials for activated carbon include coconut shells, coal (bituminous coal, anthracite), oil pitch, wood chips, sawdust, coffee grounds, rayon, acrylonitrile, and phenolic resin. The shape is not limited and includes granular, pulverized, powdery, fibrous, molded (honeycomb) and the like.

The pores of the adsorbent are called micropores having a diameter of 2 nm or less, mesopores having a diameter of 2 to 50 nm, and macropores having a diameter larger than 2 nm. It is the micropores that increase the specific surface area of the adsorbent and quickly adsorb fine particulate matter. For example, activated carbon has pores of varying diameters, from micropores to macropores. Zeolites also have relatively uniform sized micropores. Any of the adsorbents exemplified above can be used due to the presence of micropores (micropores).

The average particle size of the adsorbent should have a lower limit of 5 μm or more, preferably 10 μm or more, and an upper limit of 30 μm or less, preferably 20 μm or less. If it is less than 5 μm, the adsorbent enters the inside of the filtration filter 12 or permeates it. If it is more than 30 μm, the adsorbent is difficult to flow with the air current at a predetermined inflow air volume or a predetermined outflow air volume. The average particle size can be measured according to JIS Z 8825:2013.

The bulk specific gravity of the adsorbent should preferably have a lower limit of 0.4 g/cm ³ or more and an upper limit of 1.5 g/cm ³ or less. If it is less than 0.4 g/cm ³ , the adsorbent will be blown up by a slight breeze, making it difficult to handle. If it exceeds 1.5 g/cm ³ , it becomes difficult to flow along with the air current.

When the gas containing the adsorbent is allowed to flow from the outside to the inside of the filtration filter 12 , the adsorption agent adheres to the outer surface of the filtration filter 12 to form an absorbent layer on the outer surface of the filtration filter 12 . For the thickness of the adsorbent layer at this time, for example, the lower limit is preferably 0.5 mm or more and the upper limit is 4 mm or less. If it is less than 0.5 mm, minute turbid substances may permeate the filtration filter 12, and if it exceeds 4 mm, the liquid flow resistance may increase and the throughput per unit time may decrease.

By providing such an adsorbent layer, it becomes difficult to detect VOCs, heavy metal ions, and high-concentration normal-hexane extract substances from the filtrate B.

(Flocculant addition route 54)
FIG. 5 shows an embodiment of the liquid purification system 100 to be treated. As in the liquid purification system 100 to be treated, it is preferable to provide a coagulant addition path 54 for adding a coagulant to the liquid to be treated TL.

In the liquid purification system 100 illustrated in FIG. 5, the PAC (Polyelectrolyte Aluminum Chloride, which is an abbreviation for polyaluminum chloride. The same shall apply hereinafter.) PAC flocculant stored in the chemical injection tank 8 is transferred to the flocculant addition route. 54, it is led to a path 56 between the first sedimentation tank 2 and the ozonizer 3, and the liquid to be treated TL passing through this path 56 is added with a PAC flocculant. The flocculant added to the liquid to be treated TL is not limited to PAC, and other inorganic flocculants such as aluminum salts, iron chloride, and polyiron may be added. By adding the flocculating agent to the liquid TL to be treated in this manner, suspended solids contained in the liquid to be treated TL are easily aggregated. As a result, the suspended matter in the liquid to be treated TL aggregates and the specific gravity increases, so that it tends to settle in the lower part of the ozone treatment device 3 described later, and the precipitated matter is discharged from the discharge port provided in the lower part of the ozone treatment device 3. It becomes easy to be discharged as PS. In addition, even suspended solids (aggregated suspended solids) whose specific gravity is not so high are easily captured by ozone, so that the gap GP between the outer cylinder 41 and the inner cylinder 42 floats together with the ozone. , the scum SC is easily discharged from the discharge port 53 provided in the upper portion of the ozone treatment device 3 . Furthermore, even suspended matter that has not been removed as precipitated matter PS or scum SC in the ozone treatment device 3 is aggregated to some extent by the coagulant, so it is captured by the filtration filter 12 of the filtration device 4 provided in the latter stage. easier. Further, by adding a flocculating agent, it is possible to prevent suspended solids from reaching the deep layer of the filtration filter 12 of the filtration device 4, which has the advantage of facilitating cleaning when cleaning the filtration filter 12. be. As a result, more suspended solids in the liquid to be treated TL can be removed than when no coagulant is added. Filtrate B can be obtained.

In the liquid purification system 100 shown in FIG. 5, the coagulant is added to the path 56 between the first sedimentation tank 2 and the ozonizer 3. may be added. For example, a coagulant is added to the liquid TL to be treated stored in the primary sedimentation tank 2, or a coagulant is added to the liquid TL to be treated that passes through the path 55 between the cleaning device 1 and the primary sedimentation tank 2. You may From the viewpoint of facilitating removal of the precipitated substances PS and scum SC from the liquid TL to be treated in the ozone treatment device 3, the coagulant is added to the liquid TL to be treated before being supplied to the ozone treatment device 3 as described above. addition is most preferred. However, it is not limited to such a form. A flocculating agent may be added to the liquid to be processed TL passing through. Even when the coagulant is added to the liquid TL to be treated inside the ozone treatment device 3 or to the liquid TL to be treated passing through the path 57 between the ozone treatment device 3 and the filtration device 4, the subsequent filtration device 4 This is because there is an advantage that suspended matter can be easily removed by the filtration filter 12 of . In addition, if the coagulant is added to the liquid to be treated TL before it is supplied to the ozonizer 3, the filter 12 of the filtration device 4 can easily remove suspended solids. It is most preferable to add a coagulant to the liquid to be treated TL before it is supplied to 3.

(To-be-processed liquid purification system 100)
Finally, an embodiment of the liquid purification system 100 to be treated will be described with reference to FIG. The symbol "P" shown in FIG. 5 represents a pump.

(Washing device 1)
A cleaning apparatus 1 is an apparatus for cleaning an object to be cleaned. Objects to be washed are not particularly limited, and examples thereof include waste plastics in plastic recycling plants, rice in food factories, clothes and work clothes in laundry factories, and trains, jet engines, and construction machinery in various repair shops.

As the cleaning device 1, for example, a cleaning and dehydrating device used in the wet cleaning process in a factory for material recycling of waste plastics can be cited. Alkaline water or alkaline ionized water is often used for washing in this washing/dehydrating equipment, and the waste liquid discharged from the washing/dehydrating equipment contains deposits adhering to the waste plastic (food residue, oil, etc. in the case of food trays). ), microplastics that are finely crushed waste plastics, detergents used for cleaning, etc. Further, since water is used when rice is washed in the food factory, rice washing juice (waste liquid) is discharged from the rice washing device (corresponding to the washing device 1). In addition, since water and detergent are used when washing clothes in a laundry factory, the waste liquid discharged from the washing machine (corresponding to the washing device 1) contains various foreign substances adhering to the clothes and fibers of the clothes (clothes). includes microplastics if they are made of chemical fibers), detergents (including microplastics depending on the type of detergent), etc.

(First sedimentation tank 2)
In the system 100 for purifying the liquid to be treated shown in FIG. This waste liquid is also referred to as "to-be-treated liquid TL". Then, the waste liquid discharged from the cleaning equipment 1 and the waste liquid from the waste liquid tank 21 in the factory are mixed in the first sedimentation tank 2 . Alternatively, only the waste liquid discharged from the washing apparatus 1 may be supplied to the first sedimentation tank 2 without supplying the waste liquid from the drainage basin 21 in the factory to the first sedimentation tank 2 .

In the first sedimentation tank 2, suspended matter such as organic substances and inorganic particles (also referred to as "suspended matter" or "contaminant matter"; hereinafter the same) in the waste liquid is precipitated and removed. In addition, since the oil content floats on the upper surface of the waste liquid initially stored in the sedimentation tank 2, the floating oil is also recovered and removed. Although it is not absolutely necessary to provide the first sedimentation tank 2, it is preferable to provide it as much as possible because the effect of removing suspended solids is high and the running cost is low.

(ozonation and filtration)
As described above, the waste liquid discharged from the first sedimentation tank 2 is supplied to the ozone treatment apparatus 3 as the liquid TL to be treated. In the ozonation device 3, the ozonized liquid TS is discharged after the removal of the sediment PS and the scum SC and the ozonation of the suspended matter are performed. Next, the ozonated liquid TS is supplied to the filtering device 4, filtered by the pleated filter 12, and then the filtrate B is discharged. The filtrate B discharged from the filtering device 4 is sent to the liquid cooling device 5 in the subsequent stage. In addition, it is not necessary to send all of the filtrate B discharged from the filtering device 4 to the liquid cooling device 5 , and a part of the filtrate B may be sent to the return path 10 and then returned to the washing device 1 . Since the ozone processing device 3 and the filtering device 4 have been described in detail above, the description thereof is omitted here.

Also, the precipitated substances PS staying in the lower part of the ozonizer 3 are periodically transported from the ozonator 3 to the dehydration bag 18 and then stored in the dehydration bag 18 .

In the filtration device 4, when the ozonated liquid TS is filtered, suspended matter aggregates and accumulates on the surface of the filtration membrane 12m to form a cake K, and as the thickness of the cake K increases, the flow rate decreases. Filtration efficiency deteriorates. Therefore, the amount of liquid passing through the filtration membrane 12m is monitored, and when the amount of liquid passing becomes a predetermined value or less, the suspended solids (cake K) deposited on the surface of the filtration membrane 12m are automatically peeled off ( washing the filtration membrane 12m).

When washing the filtration membrane 12m, after filling the gap 50 between the inner surface of the filtration container 11 and the outer surface of the filtration membrane 12m with air, the washing liquid C is sprayed onto the outer surface of the filtration membrane 12m. , to wash the filter membrane 12m. It is not necessary to use the filtrate B as the cleaning liquid C, and the ozone treatment liquid TS, the liquid to be treated TL, or the like can be used. This cleaning liquid C is stored in a cleaning liquid tank 36, is pressurized by a pump (not shown) when cleaning the filtration membrane 12m, and is formed into a beam shape elongated in the vertical direction from an outlet 37 (slit). discharge. Since the filtration filter 12 is rotated in the circumferential direction by the motor M during washing, the rotating filtration filter 12 collides with the cleaning liquid C discharged in the form of a beam, and the cake K formed on the surface of the filtration membrane 12m is peeled off. do.

In addition, it is preferable to mix granular material with the liquid C for washing. By rubbing the membrane surface of the filtration membrane 12m with the particulate matter contained in the cleaning liquid C discharged from the blowout port 37, fouling is prevented, and the filtration membrane 12m is in the same state as before the start of filtration. level can be played. The granules mean powders and granules, and for example, spherical sponges such as spherical PVC sponges, beads such as spherical plastic beads and spherical perlite beads, and sands such as silica sand can be used. However, from the viewpoint of preventing deterioration of the filtration membrane 12m, it is not preferable that the particles are particles having corners such as sand, and rounded particles such as spherical particles and ellipsoidal particles are preferable. is preferred. Also, from the same point of view, the granular material should not have high hardness. Specifically, the hardness of the powder is preferably R20 to R110. Furthermore, it is preferable to uniformly disperse the granules in the liquid C for cleaning. It is preferable that the specific gravity of the granular material is, for example, 0.8 to 1.2 g/cm ³ . In addition, the granular material F preferably has a particle size suitable for recovery and reuse, that is, classification. Specifically, the particle size is preferably 0.2 mm to 1 mm, more preferably 0.4 mm to 0.7 mm. The particle size of the powder F can be measured according to JIS Z8800.

Thus, the cake K formed around the entire circumference of the filtration filter 12 is peeled off. Since the washing time is as short as about 2 minutes, the stop time of filtering by the filtering device 4 can be minimized. The used washing liquid C and the peeled cake K are mixed to form a concentrated slurry, which is stored in the discharge chute 11S of the filtering device 4, discharged from the outlet 11V, and conveyed to the concentrated slurry tank 17. In the concentrated slurry tank 17, used washing liquid C, cake K, etc. are stored, and heavy suspended matter settles in the lower part. In order to increase the amount of suspended matter that settles in the concentrated slurry tank 17, it is preferable to add a coagulant from the coagulant tank 24 to the concentrated slurry tank 17. Any flocculant can be used as the flocculant, such as the aforementioned PAC, inorganic flocculants such as other aluminum salts, iron chloride, polyiron, and the like. Precipitated substances that have settled in the lower part of the concentrated slurry tank 17 are periodically transported to the dewatering device 18 .

In the dewatering device 18, for example, a cylindrical filter can be used to separate the dehydrated sludge and squeezed liquid. This dehydrated sludge (dehydrated cake) can be disposed of as industrial waste as waste plastic sludge, and the squeezed liquid can be returned to the ozone treatment device 3 by the pump P.

Although the type of the dewatering device 18 is not particularly limited, for example, a device in which a large number of bag filters are connected can be used. The dewatering device 18 using such a bag filter preferably has a structure in which the concentrated slurry is pressure-injected into the bag filter to be filtered and dehydrated, and intermittently compressed by air pressure to reduce the water content. Also, by making the dehydrator 18 a completely closed structure, it is possible to prevent leakage of bad odors.

(Liquid cooling device 5)
The liquid to be treated purification system 100 shown in FIG. 5 is configured such that the filtrate B discharged from the filtering device 4 is supplied to the liquid cooling device 5 and the filtrate B is cooled by the liquid cooling device 5 . Specifically, for example, it is preferable to cool the filtrate B at 37 to 50°C to 32°C or less with the liquid cooling device 5 . If the temperature of the filtered liquid B after cooling (the liquid cooled by the liquid cooling device 5 is referred to as “cooling liquid”; the same shall apply hereinafter) is higher than 32 degrees, the object to be cooled is cooled by the cooling device 7 (for example, an extruder) in the subsequent stage. may not be sufficiently cooled.

Although the liquid-to-be-treated purification system 100 shown in FIG. 5 is configured to cool the filtrate B discharged from the filtering device 4, the position where the liquid cooling device 5 is provided is not limited to this location. For example, a liquid cooling device 5 is provided between the washing/dehydrator 1 and the first sedimentation tank 2 or between the first sedimentation tank 2 and the ozone treatment device 3 to cool the waste liquid (liquid to be treated TL) before the ozone treatment. You can make it work. Further, a liquid cooling device 5 may be provided between the ozonation device 3 and the filtration device 4 to cool the ozonated liquid TS before filtration. In addition, it is not necessary to provide the liquid cooling device 5 only at one of the locations described above. Two or more liquids selected from the group B may be cooled.

(Reservoir 6)
The cooling liquid discharged from the liquid cooling device 5 is stored in the storage tank 6 . The storage tank 6 is a facility for storing the cooling liquid, and the cooling liquid is supplied from the storage tank 6 to the subsequent cooling device 7 as required.

In order to disinfect the cooling liquid, it is preferable to supply the disinfecting liquid from the disinfecting liquid storage tank 9 to this reservoir 6 . For example, a liquid mainly containing sodium hypochlorite can be used as the disinfectant, but the liquid is not limited to this, and other disinfectant such as hydrogen peroxide solution may be used. The concentration and amount of the disinfectant supplied to the storage tank 6 can be arbitrarily determined, but for example, sodium hypochlorite, which is characterized by its high persistence, can be supplied at a concentration of 12%. At this time, it is preferable to adjust the supply amount of sodium hypochlorite so that the coolant in the storage tank 6 has the same level of residual chlorine concentration (0.1 ppm or more) as tap water. Since ozone OZ remains in the cooling liquid, there is almost no possibility of algae or bacteria growing in the cooling liquid.

Further, it is preferable to supply a liquid such as groundwater to the storage tank 6 when starting up the liquid purification system 100 or when the cooling liquid in the cooling device 7 is low due to evaporation or the like. The to-be-processed liquid purification system 100 shown in FIG. 5 is assumed to be used for a long period of time while circulating the waste liquid discharged from the cleaning device 1 between the cooling device 7 and the cleaning device 1. Since use causes deterioration of the waste liquid, it is necessary to discharge (discard) part of the circulating waste liquid outside the system and introduce new liquid into the system 100 . In this case, fresh liquid (eg, groundwater) may be supplied to this reservoir 6 .

(Drainage adjustment tank 19, drainage tank 20)
When the storage tank 6 overflows, part of the coolant in the storage tank 6 can be supplied to the waste liquid storage tank 19 . In the waste liquid storage tank 19, in order to discharge the liquid to the outside of the cooling liquid generation system 100, the state of the liquid to be discharged (for example, the pH of the liquid, the temperature of the liquid, and the suspended solids contained in the liquid are determined. SS for short), the biochemical oxygen demand (BOD for short) of the liquid, the amount of n-hexane extractables contained in the liquid, etc.) are measured and monitored. If the condition of the liquid is bad (for example, the amount of suspended solids is higher than the legal standard value), it is preferably returned to the first sedimentation tank 2 for repurification. Conversely, if the liquid is in good condition (for example, if the amount of suspended solids is less than the legal standard value), it is sent to the drainage tank 20 and then discharged from the drainage tank 20 to the outside of the system 100 at the desired timing. can be done. In addition, since it is difficult to remove salt and sugar in the ozone treatment device 3 and the filtration device 4, when the concentration of salt and sugar in the filtrate B becomes high, the cooling liquid is discharged from the storage tank 6 to the waste liquid adjustment tank 19. may be discharged to the outside of the system 100 after being moved.

(Cooling device 7)
The cooling liquid stored in the storage tank 6 is sent to the cooling device 7 as needed and used to cool the object to be cooled.

For example, in a waste plastic recycling plant, an extruder can be cited as a device corresponding to the cooling device 7 . Specifically, the waste plastic is washed by the washing device 1, dried and flakes (material for the extruder) are supplied to the extruder. The material supplied to the extruder is heated and melted in the extruder and then extruded from the die. The material extruded from the die is cooled in a cooling water tank in the extruder, and then cut into pellets of a desired size by a cutter in the extruder. As described above, cooling is performed in the extruder, and it is preferable to use the cooling liquid stored in the storage tank 6 when performing this cooling. Since ozone OZ (ozone OZ supplied by the ozone treatment device 3) remains in the cooling liquid, the surface of the pellet can be cleaned by the action of this residual ozone OZ, and the storage stability of the pellet can be improved. can be done.

In the food factory, a process for washing the pot used for cooking rice is required, and the cooling liquid stored in the storage tank 6 may be used for washing the pot. Furthermore, in the laundry factory, it is necessary to cool the dryer used for drying clothes so that the temperature does not rise too much. good too.

In the cooling device 7, part of the coolant is evaporated and lost. Therefore, it is preferable to replenish the storage tank 6 with the same amount of liquid (such as well water) as the lost cooling liquid.

(Return route 10)
Discarding the coolant used for cooling in the cooling device 7 is not preferable from the viewpoint of effective use of liquid resources (for example, water resources) and the viewpoint of reducing running costs. Therefore, a return path 10 is provided between the cooling device 7 and the cleaning device 1 as in the system 100 for purifying the liquid to be treated shown in FIG. and the coolant is preferably used for cleaning the object to be cleaned. It should be noted that the temperature of the used coolant often rises to around 50 degrees. By utilizing the liquid having a temperature of about 50° C. as the cleaning liquid for the cleaning device 1 in this way, it is possible to enhance the cleaning effect of the cleaning target (for example, flakes of waste plastic) and improve the quality of the cleaned target. be able to. In addition, the object to be washed is rinsed, dehydrated and dried after being washed. It is easy to remove deposits and dirt particles on the surface of the object to be cleaned (for example, waste plastic). In addition, when the waste plastic flakes are dehydrated as described above, the product temperature of the flakes after dehydration is high and the amount of water remaining in the flakes is small, so the quality of the pellets made from the waste plastic flakes can be improved. can be done. In addition, since the temperature of the cleaning liquid is lowered to some extent in the cleaning process by the cleaning device 1, the cooling load by the liquid cooling device 5 in the subsequent stage can be reduced. Furthermore, if a liquid having a temperature of around 50°C is used as the cleaning liquid for the cleaning device 1, the flakes after cleaning will be preheated to some extent. As a result, the power used by the extruder 7 can be reduced.

As described above, by continuing to circulate and reuse the waste liquid after cleaning, it is possible to effectively utilize the limited liquid resources and to greatly reduce the running cost. According to the present inventor's trial calculation, the running cost can be reduced to about 1/10 to 1/20 of the conventional apparatus.

In some cases, the amount of liquid used in the cleaning device 1 is small. In this case, instead of returning all of the used cooling liquid discharged from the cooling device 7 to the cleaning device 1, part of the used cooling liquid is returned to the cleaning device 1, and the used cooling liquid is returned to the cleaning device 1. may be returned to the liquid cooling device 5.

DESCRIPTION OF SYMBOLS 1... Washing apparatus, 2... First sedimentation tank, 3... Ozone treatment apparatus, 3T... Top plate, 4... Filtration apparatus, 5... Liquid cooling apparatus, 6... Storage tank, 7... Cooling apparatus, 8... Flocculant storage tank, 9... disinfectant storage tank, 10... return path, 11... filter container, 11S... discharge chute, 11U... filter built-in part, 11V... discharge port (of cleaning liquid and cake), 12... filtration filter (also called pleated filter), 12b... Back surface of filtration membrane (inner surface of filtration filter), 12f... Surface of filtration membrane (outer surface of filtration filter), 12m... Filter membrane, 12r... Filtrate passage, 12s... Cylindrical body, 13... (of ozonated liquid) Supply port 14 Scum tank 15 (Filtrate) discharge port 16 Ozone generator 17 Concentrated slurry storage tank 18 Deliquidizer 19 Drainage adjustment tank 20 Drainage tank 21 Drainage basin (in factory) 22 Adsorbent supply device 23 Filtrate storage tank 24 Coagulant tank 29 Filter support 35 Cleaning device 36 Cleaning liquid tank 37 Blowout port (slit ), 41... Outer cylinder, 42... Inner cylinder, 43... Liquid to be treated supply port, 44... Ozone supply port, 45... Sediment discharge port, 46... Ozonated liquid discharge port, 47... Scraping device, 47A... Shaft Part 47B... Blade part 48... Supply port (of the liquid that cleans the filtration filter) 49... Liquid level sensor 50... Gap 51... Straightening baffle 52... Scum collection part 53... Scum discharge port 100... Cooling liquid generation system, B... Filtrate, C... Filtration filter cleaning liquid (liquid for cleaning the filtration filter) K... Cake, M... Motor, P... Pump, W... Replenishing liquid (e.g. groundwater), DS... (height direction ) Lower side, GP...Gap, IN...Inside (of inner cylinder), LD...Height direction, LI...Liquid level, OZ...Ozone, PS...Precipitated substance, SC...Scum, TL...Liquid to be treated, TS...Ozone Processing liquid, US ... (height direction) upper side

Claims (5)

an outer cylinder;
an inner cylinder provided inside the outer cylinder;
an ozone supply port for supplying ozone to the gap between the outer cylinder and the inner cylinder;
a to-be-processed liquid supply port for supplying the to-be-processed liquid to the gap between the outer cylinder and the inner cylinder;
a scum discharge port provided at the top of the outer cylinder;
a discharge port for precipitated substances provided at the bottom of the outer cylinder;
an ozonated liquid outlet provided at the bottom of the inner cylinder;
has
The liquid to be treated supplied from the liquid to be treated supply port moves upward in the gap between the outer cylinder and the inner cylinder together with the ozone supplied from the ozone supply port. It moves upward inside the inner cylinder from above the gap between the cylinder and the inner cylinder, moves downward inside the inner cylinder, and is ozonated in a series of these moving processes. The processing liquid is configured to be discharged from the discharge port provided at the bottom of the inner cylinder,
An ozone treatment device characterized by: In the gap between the outer cylinder and the inner cylinder, suspended matter contained in the liquid to be treated is classified by its specific gravity,
In the gap between the outer cylinder and the inner cylinder, the suspended matter floating together with the ozone is discharged as the scum from the discharge port of the scum,
2. The ozone processing apparatus according to claim 1, wherein said suspended matter that has settled in said gap between said outer cylinder and said inner cylinder is discharged as said precipitated matter from an outlet for said precipitated matter. The to-be-processed liquid supply port is oriented in the circumferential direction of the outer cylinder,
3. The ozone processing apparatus according to claim 1 , wherein said liquid to be treated supplied from said liquid to be treated supply port rises while rotating in a gap between said outer cylinder and said inner cylinder. A liquid purification system having the ozone treatment apparatus according to any one of claims 1 to 3 ,
Having a filtration device for filtering the ozonated liquid to generate a filtrate in the latter stage of the ozonation device,
The filtering device is
a filtration vessel having a supply port for the ozonated liquid and a discharge port for the filtrate;
a pleated filter provided inside the filtration container, having an outer surface serving as a filtration surface and an interior serving as a passage for the filtrate, and formed into a tubular shape while forming a plurality of pleats by folding a flat filter medium into a bellows shape; has
Suspended matter contained in the ozonated liquid that could not be removed by the ozonation device is removed by the filtration device,
A system for purifying a liquid to be treated, characterized by: 5. A liquid purification system according to claim 4 , further comprising a coagulant addition path for adding a coagulant to said liquid to be treated before being supplied to said ozonizer .

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