JP2012167176A - Cleaning and deodorization treatment method and device for waste plastics using fenton oxidation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform decomposition and deodorization treatment of organic substances adhered to waste plastics.SOLUTION: Fractured waste plastics are introduced into a slurry tank 10, and hydrogen peroxide 12, ferrous sulfate 13, and circulating water 14 are added to the slurry tank 10, in which adjustment to be acidic and stirring are also performed. A Fenton cleaning tank 20 is divided into a number of layers 20a, 20b and 20c in the vertical direction, and a rotation shaft 22 penetrating respective layers rotates stirring blades 23a, 23b and 23c. A communication hole 48 is provided in partition plates 24a and 24b that separate layers. A Fenton cleaning tank 30 has similar structure, and the respective bottom layers are connected via piping 40. Stirred waste plastics are introduced into the top layer of the Fenton cleaning tank 20 from piping 18, and the waste plastics are allowed to overflow from the top layer of the Fenton cleaning tank 30.

Description

  The present invention relates to a plastic cleaning / deodorizing treatment method and apparatus for cleaning / deodorizing waste plastics used as containers / packaging by a Fenton oxidation method.

In addition to industrial waste, garbage can be classified according to its cause, including household waste as general waste, building waste discharged with construction, and land improvement excavation. In order to effectively use these wastes as resources, they are collected separately for each raw material contained in them. There are a wide variety of materials contained in garbage, such as iron, non-ferrous metals, earth and sand, stones and paper, wood, waste plastics (including plastic and vinyl), and generally these are heavy items such as iron and paper, wood, etc. It is sorted and processed as a lightweight product.

Among these, for waste plastics, the legalization of a recycling system that separates and collects plastic bottles and other containers and packaging wastes, and systematization corresponding to this is being planned. Effective use of some waste plastics has started.

However, if used plastic bottles, containers and packaging plastics are not properly roughly sorted, raw garbage is mixed in or the contents remain. Waste plastics used as containers and packaging include those used for food packaging, and organic substances such as sugars, aromatics, and filth are attached to the collected waste plastics, and a rotting odor ( Accompanied by garbage odor). For this reason, the waste plastics cannot be removed from the recycled plastics, which prevents the waste plastics from being used as recycled materials.

For this reason, there are some that should be recycled domestically, but are exported overseas as resources in the state of a bale compressed and stringed. Even when used as a recycled material, for example, in the case of a PET bottle, the properties of the virgin material will be different if saccharides or the like are mixed therein, so that the intended use is limited.

On the other hand, a COD treatment technique based on the Fenton oxidation method is known as a technique for performing a treatment for reducing the COD of domestic sewage and industrial wastewater. The Fenton oxidation method uses hydrogen peroxide and ferrous sulfate as a source of iron ions as a catalyst to generate hydroxyl radicals under acidic conditions, and decomposes organic substances by oxidizing the hydroxyl radicals. Is. Hydroxyl radicals have the strongest oxidizing power and react with all substances such as carbohydrates, proteins and lipids. On the other hand, due to its high reactivity, it cannot exist for a long time in a normal environment (the lifetime is about 1/100 million second ( ^10-8 seconds)), and other molecules within this time Reacts and disappears. For this reason, in the sewage treatment, the sewage, iron ions, and hydrogen peroxide are uniformly contacted and reacted by stirring with a propeller, air jet or the like. For example, Patent Document 1 proposes a structure of a Fenton reaction tank in which mixing of sewage and a chemical agent is made as uniform as possible, and discloses a technique for performing continuous treatment of sewage by connecting them in series.

Furthermore, Patent Document 2 discloses a technique for cleaning a substrate using hydroxyl radicals. The hydroxyl radical in Patent Document 2 is not obtained by the Fenton method. Rather, Patent Document 2 discloses a technique for generating hydroxyl radicals under non-acidic conditions because hydroxyl radicals are decomposed in a short time under acidic conditions, and are not suitable for application to substrate cleaning. ing. In the present technology, cleaning is performed batchwise with hydroxyl radicals while the substrate is immersed in a cleaning bath.

Patent Documents 3 and 4 disclose that the organic substance is retained in a processing apparatus or an oxidation container in a batch state and decomposed using hydroxyl radicals by the Fenton oxidation method.

Japanese Patent No. 4173706 JP 2002-92089 A JP 2004-42043 A JP 2003-200141 A

Since the hydroxyl radicals have a very short duration, the liquids are agitated and mixed with a propeller, air, or the like for the reaction between aqueous solutions such as a sewage liquid and an aqueous solution. In Patent Document 1, since both sewage and chemicals are aqueous solutions, a partition plate extending on the surface of the water is installed in the Fenton reaction tank, and only the floating unreacted substances are prevented from flowing to the next reaction tank. Good.

Waste plastics include various materials such as PET (polyethylene terephthalate), PVC (polyvinyl chloride), PE (polyethylene), PP (polypropylene), PS (polystyrene), etc. Air attaches to packaging waste plastics (mainly PP, PE, PS, but PS includes foamed PS), and floats in the reaction vessel. PET is heavier than water, but plastics used for packaging are mainly lighter than water. On the other hand, if the waste plastics remain floating in the reaction layer, the hydroxyl radical having a very short duration cannot be brought into contact with the waste plastics. Further, it cannot be continuously sent to the next reaction layer. In Patent Document 1, a stirrer or air is used for stirring in the reaction vessel, but the air further adheres to and floats on the waste plastic pieces, and the chemical is sufficiently applied to the waste plastics. The touched state cannot be maintained for a long time. The stirrer is not disclosed how to do it. Moreover, even if it reacts with a chemical | medical agent in the batch state which stayed in the processing container like patent document 2 thru | or 4, and also if necessary, it is continuous with respect to the waste plastics supplied from now on next. Fenton treatment cannot be performed. In particular, when waste plastics are crushed into confetti, the waste plastics can easily clog the inlet and outlet valves to the processing container and cause failure, so the processing container cannot be moved stably.

In addition, even if continuous processing is performed, unless the Fenton processing time is uniformly applied to the waste plastic pieces that have been input, deodorization is not sufficient for short ones, while those that have passed long processing times are The material will be affected.

Fenton oxidation method, which has strong oxidizing power and is used for wastewater treatment or soil improvement, but has not been applied to cleaning and deodorization of crushed waste plastics. In addition, attempts have been made to deodorize by introducing a deodorant. However, it is difficult to move on a commercial basis because the profitability does not match.

The present invention is an apparatus and method for cleaning and deodorizing waste plastics that decomposes and deodorizes organic substances adhering to the crushed waste plastics. It is an object of the present invention to provide an apparatus and method for cleaning and deodorizing waste plastics that are continuously processed as they are.

In order to solve the above-mentioned problems, the method for cleaning and deodorizing waste plastics according to the present invention is a method in which waste plastics with crushed decaying odor, cleaning water, hydrogen peroxide, and ferrous sulfate are introduced into a tank and stirred. The waste plastics stirred in the tank are taken out and the waste plastics are separated from the liquid by centrifugation, while the liquid separated by the centrifugation is circulated as the washing water. To do.

In addition, the present invention crushes waste plastics with organic matter and spoiled odors that cannot be removed by washing, add washing water, hydrogen peroxide and ferrous sulfate, and deodorize the waste plastics by the Fenton oxidation method. Waste plastic cleaning and deodorization treatment device, which is divided into a number of layers in the vertical direction by a partition plate, a rotating shaft that passes through each layer has a stirring blade in each layer, and each layer is Two tanks connected by a communication hole provided in the partition plate, a pipe connecting the lowermost layers of one tank, and the agitated waste plastics on the uppermost layer of the other tank It is characterized by having a pipe to be charged and a pipe for overflowing waste plastics from the uppermost layer of the other tank.

The Fenton oxidation / cleaning cleaning / deodorization system has a self-purifying action in the Fenton oxidation solution itself, so it cleans organic matter and dust odor adhering to the surface of waste plastics, and at the same time dissolves organic matter and waste odor dissolved in washing water. At the same time. Therefore, it has the greatest feature in that the cleaning water can be reused. That is, since the centrifugally dehydrated or centrifuged liquid is recirculated for cleaning, the amount of water required for cleaning can be greatly reduced. In this way, by using a cleaning water reuse system in combination, an economical cleaning / dehydration system can be configured with a drastic reduction in water usage, usually 1/10 to 1/30 of the required cleaning water amount. Further, as a result of centrifugation, there is no residual organic matter with a rotting odor contained in the washing water remaining on the waste plastics side, so that it is not concentrated by drying.

Up to now, recycled plastics for containers and packaging have been used only for products that are allowed to contain odors and foreign substances such as agricultural materials, civil engineering materials, and plastic pallets. Industrial wastes that have odors or foreign substances are incinerated or landfilled. Waste plastics treated with the apparatus according to the present invention has lost its decaying odor and has decomposed major organic substances. Building materials for indoor use, vending machines, automobile parts, etc. Can be expected to expand the application for industrial products.

Furthermore, the waste plastics are transported in order while the waste plastic pieces are being stirred in the washing tank that is multilayered in the vertical direction of the waste plastics. Can do. For this reason, cleaning and deodorization can be performed using the Fenton oxidation method which has a strong oxidizing power against cleaning and deodorization of waste plastics having a rotten odor. In addition, since the treatment time can be made uniform, it is possible to prevent waste plastics that are not sufficiently washed and deodorized from being mixed.

It is a figure which shows a processing flow. It is a figure which shows a washing | cleaning apparatus and a final water treatment apparatus. It is the perspective view to which the inside of a part of Fenton washing tank was expanded. It is a figure which shows a rinse apparatus. It is a figure which shows a water reproduction | regeneration apparatus. It is a figure which shows the principle of operation of a Fenton washing tank and a rinse tank.

Embodiments will be described with reference to the drawings. In this embodiment, waste plastics such as PE and PP, which have a specific gravity of 1 or less and are used for containers and packaging such as confectionery bags, frozen food bags, plastic bags, garbage bags, seasoning tubes and shampoo bottles, are deodorized. -An apparatus for cleaning and collecting will be described.

In FIGS. 2, 4 and 5, the reference height is indicated by hatched ground, and each component is drawn so as to indicate that it is arranged above the ground on the paper surface. Yes. Moreover, the liquid level of water etc. is represented by the dotted line.

FIG. 1 is a diagram showing a flow of cleaning waste plastics. In the figure, the triple line indicates the flow of waste plastics, and the solid line and the alternate long and short dash line indicate the flow of water.
The compressed waste plastics are taken out from the bale, and after removing the sand and sand, foreign matters are removed manually (S1 to S4). In this state, approximately 7-8% of the mass is removed. Next, waste plastics are crushed into waste plastic pieces (S5). The size of the waste plastic pieces is a confetti of about 1 cm square. It is immersed in water and separated by specific gravity (S6). By this step, expanded polystyrene, a metal having a high specific gravity, PET, PVC, or the like is removed. These are about 25% of the bale mass.

After performing centrifugal dehydration (I) (S7), organic substance decomposition treatment (S8) by Fenton oxidation is performed by the cleaning device 100 (FIG. 2) and the rinsing device 200 (FIG. 4). The organic substance decomposition treatment (S8) by Fenton oxidation includes water regeneration treatment for recycling the water to be used and final water treatment for wastewater disposal.

FIG. 2 shows the cleaning device 100 and the final water treatment device 400 (the portion surrounded by the alternate long and short dash line). First, in the cleaning apparatus 100, waste plastics subjected to centrifugal dehydration (I) (S7) are put into the slurry tank 10 by the belt conveyor 2. Hydrogen peroxide, ferrous sulfate, circulating water described later, and supplementary water lost in the process of circulating the circulating water are added to the slurry tank 10 from the pipes 12, 13, 14, and 11, respectively. Waste plastics are about 4% by weight with respect to the entire treated water. Also, the pH is adjusted to pH 2.0 to 8.0 by adding sulfuric acid through the pipe 17a using the pH sensor 17 so as to promote Fenton oxidation. The waste plastic pieces that are crushed and swelled with air are washed with water that is 25 times by weight.

The waste plastic pieces are agitated by the stirrer 16 in the slurry tank 10 and sent to the Fenton washing tank 20 having a circular cross section through the pipe 18 by the pump 15 as a Fenton liquid mixed with the waste plastic pieces. Hereinafter, the Fenton liquid in which waste plastic pieces are mixed is referred to as waste plastic mixed liquid.

The Fenton washing tank 20 is divided into a plurality of layers (in this embodiment, 20a to 20c) stacked one above the other by partition plates 24a and 24b, and the rotating shaft 22 of the stirrer 21 extends vertically to penetrate each layer. Yes. The position of the rotating shaft 22 is eccentric with respect to the center position of the Fenton cleaning tank 20 and promotes stirring. In each layer, the rotating shaft 22 is provided with stirring blades 23a to 22c that create a downward swirling flow. The reason for the downward swirling flow is to prevent the waste plastic pieces from coming into contact with the atmosphere on the liquid surface and catching the air.

FIG. 3 shows a perspective view of the partition plates 24 a and 24 b (typically 24 a) of the Fenton cleaning tank 20. The Fenton cleaning tank 20 has a circular shape in a cross section in plan view, and the top view of the partition plate 24a is also circular with the point X as the center. The rotation axis is vertically installed at a position eccentric from the center point X. The partition plate 24a of each layer is provided with a communication hole 48 through which the waste plastic piece passes at a location where the distance between the eccentric rotation shaft and the outer peripheral wall is wide. The communication hole 48 is provided with a plate 25a that can adjust the opening degree θ.

Returning to FIG. 2, the waste plastic mixed liquid in the pipe 18 is introduced from above the uppermost layer 20 a of the Fenton cleaning tank 20. The reason why it is introduced from above is to prevent the contents in the Fenton washing tank 20 from flowing back to the slurry tank 10 even if the pump 15 is stopped. The uppermost layer 20a has an overflow structure, and foamed polystyrene or the like having a light specific gravity is discharged to the pipe 29 by overflow due to the stirring flow by the stirrer 21. On the other hand, the lowermost layer 20 c has a mortar-shaped bottom surface 26, and a heavy material having a specific gravity that has settled on the bottom surface 26 through electromagnetic valves 27 a and 27 b connected in series from the lowest portion of the bottom surface 26 to the drain tank 45. It has a structure to drop. From the drain tank 45, it is sent by a pump 28 to a processing tank 50 described later via a pipe 46. Further, at a position higher than the electromagnetic valve 27a of the lowermost layer 20c, a connecting pipe 40 to the adjacent Fenton cleaning tank 30 is provided, and an opening / closing valve 44 is provided in the middle. The on-off valve 44 is used to stop the apparatus during equipment maintenance and inspection, and is not used during operation.

Similar to the Fenton cleaning tank 20, the Fenton cleaning tank 30 is divided into a plurality of layers (30a to 30c) stacked one above the other. The stirrer 31 and the partition plates 34 a and 34 b and the plates 35 a to 35 c provided in the communication hole 48 are the same as those of the Fenton cleaning tank 20. The stirring blades 33a to 33c also generate a downward swirling flow as in the Fenton cleaning tank 20, so that the movement of the waste plastic mixed liquid from the Fenton cleaning tank 20 cancels out. By adjusting the opening degree of the plates 25a to 25c and 35a to 35c provided on the partition plates of the Fenton cleaning tanks 20 and 30, it is possible to adjust the unbalance of the strength of the swirling flow generated by the stirrers 21 and 31. ing.

On the other hand, the Fenton cleaning tank 30 is different from the Fenton cleaning tank 20 in that the bottom surface of the lowermost layer 30c is not mortar-shaped and the flow of waste plastics is changed from the lowermost layer 30c to the uppermost layer 30a. It is. The uppermost layer 30a also has an overflow structure, but overflows from the position 36 lower than the opening height of the pipe 29 of the Fenton cleaning tank 20 to the pipe 39. As described above, since the movement of the waste plastic mixed liquid by the stirring blades of the Fenton cleaning tanks 20 and 30 is offset, the liquid level of the Fenton cleaning tanks 20 and 30 is determined by the overflow height by the pipe 39. The overflow to 29 will be caused by the stirring flow.

The waste plastic mixed liquid that has flowed to the pipe 39 is guided to the centrifugal dehydrator 70 for dehydration. The dehydrated waste plastic pieces are sent to the next rinsing apparatus 200 (FIG. 4). The centrifugal dewatering machine 70 is a cylinder having a spiral rotating shaft in the vertical direction and provided with a small hole through which the Fenton liquid passes. The waste plastic mixed liquid placed from the lower side of FIG. It is continuously discharged to the upper side while losing. On the other hand, the Fenton liquid centrifuged by the centrifugal dehydrator 70 contains iron ions and hydrogen peroxide that have not yet been consumed, and once collected in the sink 71, it is circulated through the pipe 14 as circulating water by the pump 72. To the slurry tank 10. The amount of water used as washing water is enormous, but in this example, this water is a Fenton liquid that has a self-cleaning action. The amount of water to be replenished is reduced.

In the final water treatment device 400, the overflow water from the pipe 29 and the sink 71 is once filtered through the mesh 52 and then introduced into the treatment tank 50. In addition, the recovered liquid from the drain tank 45 is once filtered through the pipe 46 through the mesh 51 and then charged into the processing tank 50.

In the treatment tank 50, the internal pH is detected by the sensor 58, and caustic soda is introduced from the pipe 54 so as to become alkali (pH 10 to 11). Further, the hydrogen peroxide is removed by aeration from the bottom surface with the blower 57 and sent to the neutralization tank 60 via the pipe 55. In the neutralization tank 60, the pH inside is detected by the sensor 63, and sulfuric acid is added from the pipe 64 so as to neutralize the neutralization. Then, the water is drained through the pipe 62. In addition, the treatment tank 50 treats the water in the pipes 56 and 59 from the water recycling apparatus 300, which will be described later.

On the other hand, the waste plastic pieces collected by the centrifugal dehydrator 70 are sent to the rinsing device 200. In FIG. 4, the waste plastic pieces are put into the rinsing slurry tank 210 by the belt conveyor 201. In the rinsing slurry tank 210, rinsing water is injected through the pipes 211 and 217, stirred by the stirrer 212, and sent to the rinsing tank 220 by the pump 213 through the pipe 218. The rinse water includes regenerated rinse water (pipe 211) and recycled rinse water (pipe 217), which will be described later. The rinsing tank 220 has the same multi-layer configuration as the Fenton cleaning tank 30 and has an opening / closing plate for adjusting the opening of the partition plate and the communication hole between the layers. Waste plastic fragments are taken from the uppermost layer 222a and sent from the lowermost layer 222c through the pipe 231 to the adjacent overflow tank 230. The waste plastic pieces overflowed from the overflow port 229 are sent to the centrifuge 240 through the pipe 239. Centrifuge. The centrifuge 240 has the same configuration as the centrifugal dehydrator 70 of FIG. The water separated by the centrifuge 240 is accumulated in the sink 250 and sent to the water treatment apparatus 300 via the pipe 252 by the pump 251.

Returning to FIG. 1, the waste plastic pieces separated by the centrifuge 240 are hot-air dried (S9), stored in a charge tank (S10), and then molded into resin pellets by an extruder (S11, S12). ).

Next, recycling of water used for cleaning and rinsing will be described.
FIG. 5 shows a water recycling apparatus 300. The water separated by the centrifuge 240 from the pipe 233 is sent through the pipe 252 and temporarily stored in the storage tank 310. The water overflowing the storage tank 310 is sent to the slurry tank 10 as make-up water via the pipe 11.

The water pumped from the storage tank 310 to the pump 311 is measured by the measuring mass 312, and approximately half is sent to the rinsing slurry tank 210 via the pipe 217, and half is sent as “Suzuki recycled water” via the pipe 313. And sent to the agglomeration reaction tank. The water overflowing the measuring mass 312 is returned to the storage tank 310. In the aggregation reaction tank 320, an aggregating agent 321 is added to perform an aggregation reaction. In the agglomeration reaction tank 320, the agitation is performed by the agitator 322, and the agglomerated water is sent to the pressurized flotation separation tank 340 through the pipe 323. In the pressurized levitation separation tank 340, the pressurized levitation unit 350 ejects the water flow compressed in a state where the water in the tank is once taken in and the air bubbles are taken in from the nozzle 341 into the pipe 323 at the bottom of the tank, thereby condensing the treated water. By mixing with, the iron content and waste plastics (powdered debris generated at the time of crushing) contained in the agglomerated water are actively flocated and floated. The surfacing iron and waste plastics are collected as surfacing scum (342). On the other hand, the condensed treated water from which the floating scum has been removed is sent to the rinsing slurry tank 210 as “rinse reclaimed water” via the pipe 231. A funnel-shaped drain is provided at the bottom of the pressurized flotation separation tank 340 and is sent to the processing tank 50 through a pipe 59 together with the flotation scum.

Operations of the Fenton cleaning tanks 20 and 30 and the rinsing tank 220 will be described.
FIG. 6 shows the uppermost layer of the Fenton cleaning tank 20 representing another tank. When the stirring blade 23a rotates, a vortex T is generated. However, since the waste plastic piece w is mixed, the waste plastic piece w is drawn instead of drawing the air. The center of the vortex extends to the position p of the rotating shaft 22 on the stirring blade 23a, and the waste plastic piece w is struck by the stirring blade 23a to remove the attached bubbles and dirt. Waste plastic pieces w gather at the center of the rotary shaft 22 and scatter in all directions at the point q of the partition plate 24a. At the position of the communication hole 48, the Fenton liquid and the waste plastic piece w are well mixed. Moreover, since the stirring blade 23a generates a downward water flow, the waste plastic piece w is suppressed from touching the atmosphere and containing gas.

Finally, returning to FIG. 1, the flow of the organic matter decomposition process S8 will be described as a whole.
The slurry is stirred in the slurry tank 10 (S81), and the waste plastic mixed liquid is sent to the Fenton washing tank 20 with an amount of water of 22 cubic meters (22 m ³ / h) per hour. In the cleaning process (S82), the Fenton cleaning tanks 20 and 30 having the same configuration are connected with the direction of the water flow reversed, and the amount of waste plastic mixed liquid moved into the Fenton cleaning tank 20 is almost the same. It flows out from the Fenton washing tank 30 as it is. This amount is 22 m ³ / h. This amount of Fenton liquid is recovered by the centrifugal dehydrator (II) (S83, 70 (FIG. 2)). Further, it is assumed that the amount lost due to the overflow and drain of the Fenton cleaning tank 20 is 2 m ³ / h, and the amount of water supplied through the pipe 56 is 2 m ³ / h, which compensates for this.

On the other hand, in the rinsing slurry tank 210, the amount of water from the storage tank is 10 m ³ / h, the regenerated rinse water from the water regenerator 300 is 10 m ³ / h, and the water supply is 2.1 m ³ / h, 22.1 m ³ / h is charged and stirred (S84). This is sent to the rinsing tank 220, and a rinsing process is performed (S85). The amount of water separated by the centrifuge 240 in the step of centrifugation (S89) is about the same amount, and this is sent to the storage tank 310. In the storage tank 310, 10.1 m ³ / h is sent to the aggregation reaction tank 320 (S86). In the water regenerator 300, 10 m ³ / h is recycled as regenerated rinse water to the rinse slurry tank 210 in the pressurized flotation separation tank 340, and 0.1 m ³ / h is sent to the treatment tank 50 as a flotation scum or the like (S87). . Further, 2 m ³ / h is sent to the slurry tank 10 as an overflow of the storage tank 310. A total of about 2 m ³ / h is discharged from the treatment tank 50 in the final water treatment apparatus 400 (S88).

According to this embodiment, the crushed waste plastics can be continuously subjected to Fenton treatment. Further, the processing time can be made uniform for the waste plastic pieces. The water used in the washing process is a Fenton liquid, and since it has a self-cleaning action, it can be used repeatedly as circulating water. The amount of water discharged or supplied may be small with respect to the total amount used.

In the present embodiment, in the process from the slurry tank 15 to the centrifugal dehydrator 70 in the cleaning apparatus 100 and the process from the rinse slurry tank 210 to the centrifuge 240 in the rinse apparatus 200, a valve that opens and closes the waste plastic mixture is used. Since process control is not performed and there is no cause of valve clogging, stable operation is possible.

In the embodiment, one water regenerating apparatus 300 and one water final water treatment apparatus 400 may be provided in common for the plurality of cleaning apparatuses 100 and the rinsing apparatus 200.

Further, the Fenton cleaning tanks 20 and 30 may be combined in a plurality of stages. In this case, the overflow and drain in the next-stage Fenton cleaning tank 20 are not necessarily required.

In the above examples, PE and PP having a low specific gravity as an example of waste plastics are shown as an example, but even if the specific gravity is heavier than water, such as PET, PVC, bubbles are likely to adhere in a crushed state, In many cases, it will float if left as it is, but this embodiment can also handle this.

According to the present example, the waste plastics obtained through the organic substance decomposition treatment S8 disappeared from the decaying odor, and only the odor of the plastic itself even when heated and melted. For this reason, it can be expected that the range in which waste plastics can be recycled can be expanded.

The greatest feature of using the Fenton oxidation method to regenerate and clean waste plastics is that the Fenton oxidation solution contains organic substances and waste odor-causing substances eluted from the waste plastics on the surface of the waste plastics. Oxidation and decomposition are performed in parallel with organic matter and garbage odor adhering to the material, so that substances eluted from the waste plastics do not reattach to the waste plastics, and the cleaning water is also purified at the same time. Therefore, the cleaning water can be reused.

Waste plastics have a low specific gravity and are bulky, so that a large amount of water is required for cleaning. The amount of washing water per one line, in the wash and rinse Fenton treatment, per hour, requires water 40 m ^3, when having a factory three lines, it requires water 120 m ³ / h, 8 h When it is running, and requires the water of 960m ^3.

Depending on the location of the factory, the price of water needs to be about 150 yen / m ^{3 to} 500 yen / m ³ , and costs 144,000 yen to 480000 yen, which is not practical cleaning. Fenton oxidation cleaning can be reduced to 1/10 to 1/30 by reusing this water consumption. As a matter of course, it is not possible to completely remove organic matter and garbage odor adhering to waste plastics even by washing with water alone. The cleaning method using the Fenton oxidation method is an ideal cleaning method for cleaning and deodorizing waste plastics.

The Fenton oxidation method is used to oxidize and decompose organic substances that are difficult to remove by washing with water in the recycling process of waste plastics and the rot odor associated therewith by generating hydroxy radicals. Washing water together with plastics is thoroughly washed, and then they are separated by a dehydrator. Since the Fenton oxidation solution has a self-cleaning action, the organic matter that has been transferred to the Fenton oxidation solution and the spoilage odor associated therewith are purified by oxidation and decomposition, and at the same time, additional hydrogen peroxide and iron ions are consumed. And most of it can be recycled and reused.

Waste plastics purified by Fenton oxidation cleaning liquid and separated by a dehydrator are put into a washing tank together with rinsing water and make-up water, and the residual substances adhering to the waste plastics are thoroughly rinsed by the Fenton oxidation purification process. After the transfer, it is separated into waste plastics and rinse water by a centrifuge. In the rinse water, iron and hydrogen peroxide remain, but organic matter with a decaying odor attached to the waste plastics Since it has been oxidized and decomposed, there is no residue, and it can be reused as cleaning water. It can be used to greatly reduce the consumption of makeup water.

In the washing tank or the rinsing tank, the washing tank is divided into multiple layers by partition plates, and stirring blades are provided in each layer and connected by communication holes provided in the partition plates. Using these layers, Fenton oxidation is performed. In order to perform cleaning or rinsing, waste plastics having a specific gravity different from that of water are smoothly moved through the apparatus together with the Fenton oxidation cleaning liquid or rinsing water, and sufficient cleaning or rinsing is performed without unevenness while keeping the residence time uniform. be able to.

DESCRIPTION OF SYMBOLS 100 Washing apparatus 200 Rinse apparatus 300 Water regeneration apparatus 400 Final water treatment apparatus 10 Slurry tank 20 Fenton washing tank 30 Fenton washing tank 70 Centrifugal dehydrator (II)
210 Rinse slurry tank 220 Rinse tank 240 Centrifuge 310 Storage tank 320 Condensation reaction tank 340 Pressurized flotation separation tank

Claims (4)

Waste plastics with smashed rotten odor, washing water, hydrogen peroxide and ferrous sulfate are put into a tank and stirred with a stirring blade,
Take out the waste plastics stirred in the tank and separate the waste plastics from the liquid by centrifugation,
On the other hand, a method for cleaning and deodorizing waste plastics, characterized in that the liquid separated by the centrifugal separation is circulated as the cleaning water.
The tank is divided into a number of layers in the vertical direction by a partition plate, the rotation shaft passes through each layer, a stirring blade is provided in each layer, and each layer is connected by a communication hole provided in the partition plate. The waste plastics, washing water, hydrogen peroxide and ferrous sulfate are put into the uppermost layer of the tank,
2. The method for cleaning and deodorizing waste plastics according to claim 1, wherein the stirred plastics are taken out from the lowermost layer of the tank.
Waste plastics that have passed through the lower layer of the tank are divided into a number of layers in the vertical direction by a partition plate, the rotating shaft passes through each layer and rotates a stirring blade provided in each layer, and each layer is Introduced into the bottom layer of other tanks connected by the communication holes provided in the partition plate,
3. The method for cleaning and deodorizing waste plastics according to claim 2, wherein the centrifugal separation is performed on waste plastics that have passed through the uppermost layer of another tank.
Waste plastics with organic substances that cannot be washed with water and stale odors are crushed and washed with water, hydrogen peroxide and ferrous sulfate, and waste plastics are deodorized by the Fenton oxidation method. A deodorizing apparatus,
Divided into a number of layers in the vertical direction by the partition plate, the rotating shaft that penetrates each layer has a stirring blade in each layer, and each layer is connected by a communication hole provided in the partition plate Two tanks,
Piping connecting the bottom layers of one tank,
A pipe for introducing the agitated waste plastics into the uppermost layer of the other tank;
An apparatus for cleaning and deodorizing waste plastics, characterized by having a pipe for overflowing waste plastics from the uppermost layer of the other tank.