JP2002069234A - Treating process for waste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a treating process for a waste, comprising treatments of changing the waste containing polyvinyl chloride or other chlorine-containing resins into a waste slurry, carrying out a pyrohydrolytic reaction, thereafter separating into a fuel cake and a filtrate, electrolytically treating the filtrate and adding an aqueous alkaline solution obtained to the waste slurry, characteristically comprising, at the time of electrolytically treating the filtrate, stably removing of chlorine or chlorides in the filtrate by preventing a membrane between an anode chamber and a cathode chamber from the clogging with deposits. SOLUTION: The treating process for waste comprises the steps: changing a solid waste containing polyvinyl chloride- and the other chlorine-containing resin into a waste slurry by pretreating means; hydrolytically treating the above waste slurry at a reaction vessel into a reacted slurry; flushing the above reacted slurry at a flush vaporizer, then separating into a dechlorinated fuel cake and a filtrate; and then adjusting the pH to at most 3 by adding a chlorine gas or hydrochloric acid to the above filtrate to thereby separate the deposits; electrolytically treating by a diaphragm method the filtrate after separating the above deposits; and adding the alkaline aqueous solution obtained by the above electrolytic treatment to the above waste slurry.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for hydrothermal decomposition of organic solids such as municipal solid waste and industrial waste, in particular, waste containing vinyl chloride and other chlorine-containing resins into a waste slurry. And then separating the filtrate into a fuel cake and a filtrate, and subjecting the filtrate to electrolytic treatment and adding it as an aqueous alkaline solution to the waste slurry. More specifically, the present invention relates to a waste treatment method for stably performing the electrolytic treatment of the filtrate.

[0002]

2. Description of the Related Art The so-called solid waste such as general waste such as municipal waste and industrial waste discharged from factories and the like is increasing year by year. Particularly, municipal waste containing a large amount of vinyl chloride and other chlorine-containing resins. Also, industrial waste has a problem of toxic dioxin, and it cannot be dealt with by conventional disposal methods such as landfills, and several disposal methods have been proposed. One of them is disclosed in JP-A-11-262.
No. 741. That is, solid waste is crushed in water and recyclable iron in the form of water slurry,
After recovering useful materials such as aluminum and glass, dehydration is performed to a state having an appropriate moisture value, and then, under high-temperature and high-pressure conditions, a hydrothermal reaction is performed for a predetermined residence time to form a high-temperature and high-pressure reaction slurry. After obtaining, it is disclosed that the waste is treated by flashing to obtain a cake-like dechlorinated raw fuel and a filtrate, and electrolytically treating the filtrate and circulating it as an aqueous alkaline solution to the reaction system. I have. This method has the following features. Cl ₂ and H, which do not generate highly toxic dioxin and are problematic in the combustion method
There is no corrosion trouble in the subsequent air preheater or waste heat recovery boiler due to generation of Cl. When dechlorinating waste containing organic chlorine compounds by hydrothermal reaction, the generated alkali salts are discharged out of the system. It is unnecessary and does not require a large amount of heat energy for evaporating water. Since the filtrate after the hydrothermal reaction is circulated and used, the amount of wastewater can be reduced, and wastewater treatment facilities and treatment costs can be reduced.

[0003]

However, in the above-mentioned method for treating waste containing vinyl chloride or other chlorine-containing resin, when the filtrate is subjected to electrolytic treatment, polyethylene terephthalate (PET) is contained in the waste as a raw material. ),
If the reaction slurry after hydrothermal treatment, such as dioctyl phthalate (DOP), contains a substance that generates a water-insoluble organic acid such as phthalic acid, solids precipitate in the anode chamber of the electrolysis apparatus, Deposition of the substance is not preferable because it causes a problem of clogging of the membrane separating the anode chamber and the cathode chamber of the electrolytic device.

[0004] The present invention has been made in view of the above-mentioned problems in treating municipal waste and industrial waste containing vinyl chloride and other chlorine-containing resins as described above. Waste containing vinyl chloride and other chlorine-containing resins is converted into a waste slurry, and then, after a hydrothermal decomposition reaction, separated into a fuel cake and a filtrate, the filtrate is subjected to electrolytic treatment, and the obtained alkaline aqueous solution is subjected to the waste slurry. In the treatment of wastes to be added to the filtrate, when the filtrate is subjected to electrolytic treatment, clogging of the membrane separating the anode chamber and the cathode chamber of the electrolyzer by the precipitate is prevented, and the filtrate in the filtrate is stably contained. It is an object of the present invention to provide a method for treating waste which removes chlorine or chloride.

[0005]

In order to achieve the above object, according to the present invention, a solid waste containing vinyl chloride or another chlorine-containing resin is converted into a waste slurry by a pretreatment means, and the waste slurry is used as a waste slurry. The reaction slurry is hydrothermally reacted to form a reaction slurry, the reaction slurry is flashed by a flash evaporator, and then separated into a fuel cake and a filtrate which are dechlorinated by a separation means. A gas is blown or hydrochloric acid is added to adjust the pH to 3 or less, and the filtrate obtained after separating a solid substance precipitated from the filtrate is subjected to electrolytic treatment by a diaphragm method, and the alkaline aqueous solution obtained by the electrolytic treatment is applied to the waste slurry. Was added. The present invention provides a process for the subsequent electrolytic treatment by blowing chlorine gas or adding hydrochloric acid to the filtrate before the electrolytic treatment to adjust the pH to 3 or less to precipitate and separate the hardly soluble organic acid present in the filtrate. In this case, no solid matter is deposited in the anode chamber, the clogging of the diaphragm of the electrolysis apparatus is prevented, and the waste can be stably processed without any trouble.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A specific embodiment of the waste treatment according to the present invention will be described below in detail with reference to FIGS. FIG. 1 is a block diagram of a system configuration according to an embodiment of the present invention, FIG. 2 is a system block diagram in which a filtrate is subjected to electrolytic treatment using an electrolytic device using a diaphragm, and FIG. 3 is a case where a small amount of vinyl chloride is contained in solid waste. FIG. 4 is a system block diagram of a second case, and FIG. 5 is a system block diagram of a third case.

First, a waste disposal system in which the waste disposal method of the present invention is implemented will be described in detail with reference to FIG. Wastes collected from various places and containing solids such as unsorted chlorine-containing resins are subjected to a pretreatment and then supplied to a pyrolysis treatment step.

[0008] In the pretreatment step, when treating wastes containing vinyl chloride and other chlorine-containing resins which are basically unsorted, useful materials such as iron, aluminum and glass which can be recycled are included. Therefore, it is necessary to collect the waste first and slurry it to such an extent that the solid waste can be transported for continuous operation of the solid waste treatment system. A pretreatment means 10 for this purpose is provided, and this pretreatment means 10 is composed of a crushing device, a separation device for useful materials, a dewatering device, and the like.

Therefore, in the pretreatment means 10, the solid waste containing the chlorine-containing resin in an unsorted state is made into a water slurry by crushing in water, and is contained in the crushed material at this slurrying stage. Utilizing the difference in specific gravity of incombustibles, useful materials such as recyclable iron, aluminum and glass are collected. Then, the water slurry containing the solid waste from which the incombustibles have been removed is dewatered to a solid content of about 8 to 20% by weight, preferably about 14% by weight, and has such a viscosity that it can be transported to the subsequent processing step. It is adjusted to be.

The waste slurry treated by the pretreatment means 10 is temporarily stored in a storage tank 12, where it forms a buffer between the treatment by the pretreatment means 10 and the subsequent treatment step. The waste slurry discharged from the storage tank 12 contains an alkaline aqueous solution 2
8 has been added. The waste slurry in the storage tank 12 is supplied to a downstream reactor 1 by a pumping means such as a high-pressure pump 13.
4 so as to generate a hydrothermal reaction while flowing through the reactor 14.

The operating temperature in the reactor 14 is from 250 to 350
The temperature is raised to an appropriate temperature of about
The waste slurry is fed while being pressurized to about 170 atm by step 3, and the temperature is raised to the reaction temperature before the reactor 14 in advance.
The temperature is raised stepwise to the reaction temperature by the heat exchanger 16 and the second heat exchanger 18 before being fed to the reactor 14. The waste slurry thus heated is supplied to the reactor 14.
In the process of passing through, the hydrothermal decomposition is carried out by a hydrothermal reaction while maintaining the reaction temperature and at a pressure higher than the saturated steam pressure of the reaction temperature for a reaction time of several minutes to tens of minutes.

In the present embodiment, the reaction slurry after the hydrothermal reaction in the reactor 14 is flashed using a flash evaporator 20 as a cooling device, and steam generated by flash evaporation is supplied to the first heat exchanger 16. System. That is, the waste slurry is heated to the reaction temperature in a stepwise manner, and then sent to the reactor 14,
A hydrothermal reaction is performed under predetermined operating conditions, flashed by isenthalpy expansion using a flash evaporator 20, and the obtained steam is used for raising the temperature of the waste slurry. In order to increase the efficiency of such heat recovery, it is desirable to reduce the flash pressure in several stages. Further, by compressing the flash steam (for example, by heat pump), the efficiency of heat recovery can be further improved.

The reaction slurry from the reactor 14 is flashed in a flash evaporator 20 and reduced to atmospheric pressure. During the process of concentrating the reaction slurry stored in the flash evaporator 20 by a centrifugal separator or the like constituting the separation means 24,
A filtrate 29a containing dissolved gas, salt, and the like, and a dechlorinated fuel cake 27 are obtained. Of these, the fuel cake 27 is burned in a heating medium heating furnace 34, and the combustion heat is used to heat the fuel cake 27 with the second heat exchanger 18. The heating medium circulating between the medium heating furnaces 34 is heated.
Since the flash steam after heating the waste slurry in the first heat exchanger 16 is condensed, the condensed liquid is used as a washing liquid for the fuel cake 27 obtained by separation by the separation means 24.

The fuel cake 2 is washed by condensed liquid.
7. The mother liquor containing chloride ions in 7 is replaced with a condensate,
A fuel cake 27 containing a dechlorinated combustible water concentration of 20 to 60% by weight is obtained. The condensed liquid is used as a cleaning liquid for the fuel cake 27. In consideration of the case where the condensed liquid alone is insufficient as the cleaning liquid, a flash steam condensing line connected from the first heat exchanger 16 to the separating means 24 is taken into consideration. It is desirable to provide a supply line for makeup water in the middle of the process.

The waste slurry is hydrothermally reacted in the reactor 14, and the obtained reaction slurry is separated by the separating means 24 to obtain the fuel cake 27 and the filtrate 29a. If the proportion of the chlorine-containing resin contained in the waste material used as the raw material for this treatment is large, the filtrate 2
9a via the precipitation / separation means 25
6 (see FIG. 1). Further, when the proportion of the chlorine-containing resin contained in municipal solid waste or industrial waste (particularly, waste used as a raw material in the present treatment) is small, a part of the filtrate 29a (X in FIG. 3) is reduced. The remaining filtrate 29a (Y in FIG. 3) is directly supplied to the electrolysis means 26 via the precipitation / separation means 25 and is not supplied to the precipitation / separation means 25, but is directly used for slurry adjustment in the pretreatment step. It is circulated as water.

A case where the entire filtrate 29a is fed to the electrolytic means 26 via the precipitation / separation means 25 will be described with reference to FIG. In the conventional method, the filtrate 29a is supplied to the electrolytic means 26 as it is, but in the present invention, the precipitation / separation means 25 is provided before the electrolytic means 26. In the precipitation / separation means 25, hydrochloric acid (HCl) is blown or chlorine (Cl ₂ ) is added to the filtrate 29a obtained by separating the reaction slurry by the separation means 24, so that the pH is lowered to 3 or less. Filtration of solids precipitated by
Separated and obtained filtrate 29b is fed to the next electrolytic means 26. The treatment by the separation / separation means 25 prevents solid matter from being deposited in the next electrolysis means 26 and prevents clogging of the membrane separating the anode chamber and the cathode chamber of the electrolysis apparatus, which has been a problem in the conventional method. it can.

The filtrate 29b is electrolytically treated by the electrolytic means 26 and decomposed into chlorine gas, hydrogen gas and an aqueous alkaline solution 28. The electrolytic means 26 is an electrolytic means using a diaphragm method, and it is preferable to use a filter cloth or filter paper made of borosilicate glass fiber for the diaphragm. FIG. 2 shows a schematic diagram of the electrolysis apparatus. Reference numeral 50 denotes an electrolysis device, which includes a diaphragm 52, an anode 54, and a cathode 56, and is disposed in parallel with each other. Electrolysis device 50 from one end to the other end of electrolysis device 50
Is divided into two, and is divided into two to form an anode chamber 58 and a cathode chamber 60. The anode chamber 58 constituting the electrolysis apparatus 50 has an inlet for the filtrate 29 b at one end thereof, and the cathode chamber 60 has an outlet for the alkaline aqueous solution 28 on the side opposite to the inlet.

Anode chamber 58 leading to the inlet of filtrate 29b
The anode 54 is disposed along the longitudinal direction of the anode chamber 58, and when the filtrate 29b flows, chlorine gas is generated by an electrode reaction. A cathode 56 is disposed along the longitudinal direction of the cathode chamber 60 having an outlet for the alkaline aqueous solution 28 generated after one electrolysis. On the other hand, with respect to the diaphragm 52, the filtrate 29b which has been introduced from the inlet and subjected to an electrode reaction at the anode 54 passes through the diaphragm 52, and subsequently moves to the cathode chamber 60, where hydrogen gas is generated by the electrode reaction and hydrogen ions are removed. The alkaline aqueous solution 28 is discharged from the outlet of the cathode chamber 60.

The aqueous alkaline solution 28 obtained by the electrolytic means 26 is temporarily stored in an aqueous alkaline solution tank 30 and added to a waste slurry to be subjected to a hydrothermal reaction. Since vinyl chloride and other chlorine-containing resins generate hydrogen chloride during the hydrothermal reaction, the hydrogen chloride generated by the addition of the alkaline aqueous solution 28 is neutralized. This prevents corrosion of liquid-contact parts such as a reactor, a heat exchanger, and other piping.

The alkaline substance supplied from the alkaline aqueous solution tank 30 via the alkaline aqueous solution supply pump 32 is injected continuously, and the injection amount is an amount necessary for neutralizing the generated hydrogen chloride. It is necessary to adjust the alkali concentration or the addition amount of the aqueous alkali solution 28 according to the content of the chlorine-containing resin contained in the above.

The alkali concentration of the alkaline aqueous solution 28 is controlled by the amount of current for electrolysis. The injection position is such that when the amount of the solution is large, it is supplied to the pretreatment step as water for forming a slurry, but when the amount is small, Is preprocessing means 1
0 or directly into the storage tank 12 between the storage tank 12 and the high pressure pump 13
It may be supplied directly to. The alkaline aqueous solution supply pump 32 is a variable pump that can be adjusted according to the pH value of the reaction product.

The specific contents of the treatment method using such a waste treatment system will be described below. So-called solid waste containing vinyl chloride and other chlorine-containing resins in organic solids such as municipal solid waste and industrial waste is introduced into the treatment system in a mixed unsorted state. The unsorted waste is mixed with the alkaline aqueous solution 28 or the filtrate 29a in the first pretreatment means 10 and pulverized to form an aqueous slurry from which useful inorganic substances such as iron and aluminum are separated to contain organic solids. Generate waste slurry.

In the pulverization process, several m of solid matter is obtained by crushing in water.
m, so that an aqueous slurry is obtained, and iron and the like are separated and removed during crushing in water. Next, this aqueous slurry is put into a cyclone,
Here, useful materials such as aluminum and glass are separated, and the slurry containing solid waste is adjusted to increase the solid concentration within a range that can be pumped through a dehydrator (about 14).
(% By weight). The waste slurry having been subjected to the pretreatment is sent to the reactor 14 by the high-pressure pump 13.

In the present invention, a large amount of chlorine-containing resin such as vinyl chloride which generates hydrogen chloride upon thermal decomposition is allowed to be contained in the solid waste. Hydrogen chloride generated in the reactor 14 is neutralized by the added alkaline aqueous solution 28.

The alkaline aqueous solution 28 is supplied to the reactor 1
The amount added (and the alkali concentration in the alkaline water) so that the pH of the reaction slurry at the outlet of Step 4 becomes weakly acidic 4 to 6.
Can be adjusted. By controlling the electrolytic current so that the pH of the reaction product slurry at the outlet of the reactor 14 becomes weakly acidic, continuous operation of the treatment of solid waste containing chlorine-containing waste becomes possible. Also, the reactor 14
By adjusting the alkali concentration and the addition amount of the aqueous alkali solution so as to detect the outlet pH and maintain the predetermined pH, it is possible to cope with fluctuations in the amount of vinyl chloride and other chlorine-containing resins in the solid waste to be treated.

The waste slurry into which the alkaline aqueous solution 28 has been injected is supplied to the reactor 14 by the high-pressure pump 13, and the first heat exchanger 16,
The second heat exchanger 18 preliminarily sets the temperature from room temperature to the reaction temperature 2
It is heated stepwise to 50-350 ° C. The waste slurry sent via the first heat exchanger 16 and the second heat exchanger 18 is preheated by the heat of the flash steam generated when flashing from the reactor 14 to the flash evaporator 20, Medium heating furnace 34 and second heat exchanger 1
Reaction temperature of 250 to 350 ° C. by heat medium circulating between 8,
Desirably, the temperature is raised to about 325 ° C. and introduced into the reactor 14.

The slurry is held for several tens of minutes in the reactor 14, and the liquid pressure is set to be higher than the saturated vapor pressure at that temperature to prevent boiling. The reaction slurry from the reactor 14 is flashed by the flash evaporator 20 and reduced in pressure to atmospheric pressure, at which time steam is generated. The reaction slurry stored in the flash evaporator 20 is separated into the fuel cake 27 washed with the flash condensate and the filtrate 29a in the process of being concentrated by a centrifugal filter or the like constituting the separation means 24.

Here, depending on the amount of vinyl chloride in the municipal solid waste or industrial waste, part or all of the filtrate 29a separated by the separation means 24 is passed through the precipitation / separation means 25 to the electrolysis means 26. A judgment is made as to whether or not to feed the paper. When the amount of vinyl chloride in the raw material waste such as municipal waste and industrial waste is large, as shown in FIG.
9a is entirely passed through the precipitation / separation means 25
6 and supplied to the electrolytic treatment. On the other hand, when the amount of vinyl chloride in the raw material waste such as municipal solid waste and industrial waste is small, a part (X) of the filtrate 29a passes through the precipitation / separation means 25 as shown in FIG. While being fed to the electrolytic means 26, the remaining filtrate 29a (Y) is deposited and
It is circulated and used directly as water for adjusting the waste slurry in the pretreatment step without using the separation means 25. The ratio of X and Y in the filtrate 29a is determined so that the amount of sodium chloride in the system is maintained at a predetermined value.

The precipitation / separation means 25 adds hydrochloric acid (HCl) to the filtrate 29a obtained by separating the reaction slurry by the separation means 24.
Is blown or chlorine (Cl ₂ ) is added, and the pH is lowered to 3 or less to precipitate a solid, the precipitate is filtered and separated, and the filtrate 29 b is supplied to the next electrolytic means 26. According to the conventional treatment method, a waste water as a raw material generates a water-insoluble organic acid such as phthalic acid in a reaction slurry after hydrothermal treatment such as polyethylene terephthalate (PET) and dioctyl phthalate (DOP). When the filtrate a is contained, when the filtrate a is electrolyzed, solids precipitate in the anode chamber of the electrolysis apparatus and clogging of the membrane separating the anode chamber and the cathode chamber of the electrolysis apparatus occurs. Means 2
By separating the precipitates in step 5, solids do not precipitate in the next electrolytic treatment, and clogging of the diaphragm 52 of the electrolytic device 50 can be prevented. This is because the alkali salt of an organic acid (mainly phthalic acid), which is hardly soluble in water, dissolved in the filtrate (alkaline salt is considerably soluble in water) is adjusted to the pH accompanying the generation of chlorine in the anode chamber of the electrolytic device. This is considered to be due to the precipitation and return to the organic acid due to the decrease.

Electrolysis device 5 using diaphragm method of electrolysis means 26
At zero, as shown in FIG. 2, the filtrate 29 b introduced into the anode chamber 58 of the electrolysis apparatus 50 generates chlorine gas by the anode 54. The remaining filtrate 29b passes through the diaphragm 52 and moves to the cathode chamber 60. At this time, the alkaline aqueous solution 28 after generating the hydrogen gas by the cathode 56 in the cathode chamber 60 is discharged from the outlet of the cathode chamber 60, It is fed to the alkaline aqueous solution tank 30.

In the present invention, the electrolytic treatment is performed by the diaphragm method using the diaphragm 52. However, in the electrolysis by the ion exchange membrane method, clogging of the ion (cation) exchange membrane is prevented.
It is necessary to remove divalent metal ions from the filtrate almost completely, and the operation is costly and impractical. Asbestos is conventionally used for the diaphragm, but asbestos is a substance causing environmental problems and is not preferred. Although a fluororesin diaphragm is also used as an electrolytic diaphragm, in the electrolysis of a filtrate similar to a dilute saline, the case of using a diaphragm made of borosilicate glass is better than the case of using a fluororesin diaphragm. Easy and efficient electrolysis is possible, for example, high current efficiency and low potential difference (electrolysis voltage). For this reason, it is preferable to use a diaphragm made of borosilicate glass fiber as the diaphragm 52.

In the above example, the steam generated by flash evaporation of the reaction slurry from the reactor 14 by the flash evaporator 20 is supplied to the first heat exchanger 16 to preheat the waste slurry and to heat the waste slurry. Although the waste slurry is preheated by the heated heat medium while circulating between the exchanger 18 and the heat medium heating furnace 34, the first heat exchanger 1
While dividing 6 into multiple stages, it is also possible to increase the amount of heat recovery by performing flash in multiple stages to obtain steam having different pressures and supplying the steam to each stage of the first heat exchanger 16 configured in multiple stages. is there. Further, by providing a vapor compressor and pressurizing the flash steam, it is possible to increase the condensation temperature and increase the heat recovery. Further, as shown in FIG. 4, the system can be used as a system obtained by adding a self-heat exchange system to the system shown in FIG.

Further, as shown in FIG. 5, based on the system shown in FIG. 1, the reaction slurry is once passed through a cooler 31 in order to effectively use the sensible heat of the reaction slurry at the outlet of the reactor 14. In order to use the medium for heating and energizing, a system in which a cooler 31 is disposed downstream of the reactor 14 and the heat medium is circulated and heated by the heat medium circulation pump 61 between the third heat exchangers 19 may be used. .

[0034]

As apparent from the above description, the present invention has the following advantages. That is, the present invention provides a solid waste containing vinyl chloride or other chlorine-containing resin as a waste slurry by a pretreatment means, and a hydrothermal reaction of the waste slurry in a reactor to form a reaction slurry. After flushing the slurry with a flash evaporator, the slurry is separated into a dechlorinated fuel cake and a filtrate by a separation means, and the filtrate is blown with chlorine gas or hydrochloric acid is added to adjust the pH to 3 or less. By subjecting the filtrate after separating the solid substance precipitated from the filtrate to electrolytic treatment by a diaphragm method, by adding an aqueous alkaline solution obtained by the electrolytic treatment to the waste slurry,
During the electrolytic treatment of the filtrate, solids do not precipitate in the anode chamber, preventing clogging of the diaphragm of the electrolyzer, removing chlorine or chloride in the filtrate, and stably treating waste without trouble. I can do it.

[Brief description of the drawings]

FIG. 1 is a system configuration block diagram of an embodiment according to the present invention.

FIG. 2 is a system block diagram in which a filtrate is subjected to electrolytic treatment using an electrolytic device using a diaphragm.

FIG. 3 is a system configuration block diagram of an embodiment in a case where a small amount of vinyl chloride is contained in solid waste.

FIG. 4 is a system block diagram of a second case.

FIG. 5 is a system block diagram of a third case.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Pretreatment means 12 Storage tank 13 High pressure pump 14 Reactor 16 1st heat exchanger 18 2nd heat exchanger 19 3rd heat exchanger 20 Flash evaporator 24 Separation means 25 Precipitation / separation means 26 Electrolysis means 27 Fuel cake 28 Alkaline aqueous solution 29a Filtrate 29b Filtrate 30 Alkaline aqueous solution tank 31 Cooler 32 Alkaline aqueous solution supply pump 34 Heat medium heating furnace 50 Electrolyzer 52 Diaphragm 54 Anode 56 Cathode 58 Anode chamber 60 Cathode chamber 61 Heat medium circulation pump

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C25B 9/00 B09B 5/00 Q // C02F 1/06 C25B 1/00 Z C08L 27:06 9/00 FF term (reference) 4D004 AA07 AB06 AB07 BA03 CA22 CA44 CA50 CB31 DA02 DA03 DA20 4D034 CA13 4D061 DA08 DB08 EA02 EB13 FA11 FA13 4F301 AA17 CA09 CA23 CA64 4K021 AA01 AA03 BA09 DB05 DB13

Claims (1)

[Claims] 1. A solid waste containing vinyl chloride or other chlorine-containing resin is converted into a waste slurry by a pretreatment means, and the waste slurry is hydrothermally reacted in a reactor to form a reaction slurry. Was flashed by a flash evaporator, and then separated into a fuel cake and a filtrate which were dechlorinated by a separation means. The obtained filtrate was blown with chlorine gas or added with hydrochloric acid to adjust the pH to 3 or less. A waste treatment method comprising subjecting a filtrate obtained after separating a solid substance precipitated from an aqueous solution to electrolytic treatment by a diaphragm method, and adding an aqueous alkaline solution obtained by the electrolytic treatment to the waste slurry.