GB2291420A

GB2291420A - Destruction of chlorine-containing waste substances

Info

Publication number: GB2291420A
Application number: GB9508580A
Authority: GB
Inventors: Yoshio Miyashita; Noboru Masuko
Original assignee: Kokan Kikai Kogyo KK
Current assignee: Kokan Kikai Kogyo KK
Priority date: 1994-07-20
Filing date: 1995-04-27
Publication date: 1996-01-24
Also published as: AU1790095A; CA2152741A1; GB9508580D0; JPH0824364A; JP2681752B2; DE19514309A1

Description

2291420 A METHOD OF HARMLESSLY DECOMPOSING CHLORINE-CONTAINING SUBSTANCES

CONTAINED IN INDUSTRIAL WASTE This invention relates to an economical method of 5 harmlessly decomposing chlorine-containing substances contained in industrial waste.

The term "chlorine-containing substances contained in industrial waste" used herein is intended to refer to industrial wastes which contain chlorine-containing substances, such as organic chlorides including vinyl chloride or polychlorobiphenyl, hereinafter referred to as PCB. More specifically, this term is intended to refer to various electrical components, such as transformers or capacitors using insulating oil which contains PCB; PCB- containing copying materials, such as ink, transfer papers, and the like. Furthermore the term "chlorine-containing substance" as used herein is intended to refer mainly to organic chlorides such as PCB, vinyl chloride, shredder dust containing vinyl chloride, chloro-nitropheron (CNP), chlorine-containing agricultural chemicals, such as trichlorobenzene and the like.

PC], a typical example of a chlorine-containing substance, is a general term for various chlorides of biphenyl, a mixture of chlorine containing compounds, each having 2 to 6 chlorine atoms per molecule. Herein 7 C, the term "PCB" refers to a compound which consists of H and Cl and which has the molecular formula: CIA10-n)C1n (n=2 to 6). PCB is physically and chemically stable, has excellent heat resistance and electrical insulation properties. It has been broadly used by itself or in 2 combination with other materials in industrial products. For example, it has been used as a component of insulating oil for electrical equipment, in heating mediums, lubricants, transfer papers, copying ink, copy materials for copying machines and the like.

However, PCE-containing substances have been found to be hazardous to humans, pollute the environment and are difficult to decompose. Because of these problems, the production of PCE has been suspended and any used PCE have been collected. There is a demand for an effective method of harmlessly decomposing the stored PCB_ containing products.

Up to the present, various techniques for harmlessly decomposing chlorinecontaining industrial waste such as PCE have been investigated, researched and developed. A method which is used on an industrial scale globally is a high-temperature thermal decomposition method.

According to the Environmental Protection Agency of the U.S.A., to harmlessly decompose liquid PC13, it must be confined and atomized in a furnace at 12000C for 2 seconds or longer. As described by D.S. Duvall, W.A.

Rubey et al. (EPA Report, 1977) the thermal decomposition of PCE is initiated by exposure to 6000C for that at 8000C or higher, 99.9'-. of decomposition occurs in I second.

1 second, and the thermal The detailed physical and chemical characteristics of PC5 have already been clarified. It is generally known that PC5 decomposes almost completely within 1 second at high- temperature in an oxidizing atmosphere at 3,0 GOO'C or higher. Thus it is generally known that, for example, at a high temperature of IIOO'C or higher, up to 99.99990-. is thermally decomposed WthJn G.3 second.

- 3 Unexamined Japanese Patent Publication (Kokai)No.

232073/1988 proposes a process for harmlessly decomposing a PCB-containing transformer. The process comprises separating PCB from the transformer, charging the transformer body together with the PCB or charging both the separated case of the transformer and its contents into the furnace, heating the transformer with the PCB present or the separated case and its contents to a temperature lower than 1100"C to vaporize the PCB, and igniting the PCB at a high temperature to decompose it.

In unexamined Japanese Patent Publication Wokai) No. 241586/1988 a process for harmlessly decomposing a capacitor containing PCB is proposed.

The proposed process comprises draining liquid PCB from the capacitor; dividing the capacitor into the case portion and the internal portion; and maintaining these at a temperature of between 11000C and 14000C in an incinerator. The case and the internal portion of the capacitor may be placed in the same incinerator or in separate incinerators. The PCE vapor and the combustion gas discharged from the incinerator or incinerators are thermally decomposed through the use of a thermal-decomposition furnace maintained at a temperature between 12000C to 15000C.

Equipment for the thermal decomposition of liquid PCE at a high temperature has also been developed. The equipment utilizes an incinerator designed to treat liquid waste containing organic chlorine compounds (see Kankyokagak-i, vol. 19, No. 12 (1990)) - The incinerator is provided with a spray nozzle to more effectively and completely decompose PCB. The combustion temperature of the furnace is set at about 16000C, with the temperature at the outlet kept at 1450'C.

4 In this high temperature incinerator, the residence time of the gas is set at 2 seconds or longer, the HCl evolved is absorbed into water and neutralized. The waste-gas and the waste-water from the above-mentioned equipment may contain, in addition to non-decomposed PCB, hazardous dioxin (PCDDs) and dibenzofuran (PCDFs) which may have been produced concurrently during the thermal decomposition of PCB. The production of these hazardous materials is a serious problem. As a counter-measure, if such hazardous components are produced, then they can be removed from the waste-gas and waste-water by passing these through an activated-carbon absorber.

However these processes recruire h i h A c arg ng t e ow-temnerature I chlorine-containing substance into a incinerator; then charging both the PCB vapor and/or the gas generated from the incinerator into a thermal decomposition furnace to decompose both the generated gas and the PCE vapor at a high temperature. Such processes, therefore, require a specially designed incinerator and a specially designed thermal decomposition furnace, which are expensive to set up and operate. Presently, the cost for such equipment is too high. But processes using existing equipment cannot completely decompose the chlorine-containing substance.

As a result, the storage of waste PC13 and the like in containers is unavoidable. During long-term storage of waste PCE and the like, there is always the potential of leakage which would constitute a serious source of pollution. Therefore, a relatively inexpensive process for economically and harmlessly decomposing chlorinecontaining substances, such as PC13, is needed.

It is an object of the present invention to provide an economical process for the complete and harmless decomposition of chlorine-containing industrial waste using a conventional metal melting-refining furnace.

Thus it is an object of the present invention to provide a method for thermally decomposing a chlorine containing substance (e.g. insulating oil) contained in scrap such as a transformer, a capacitor or the like.

According to one aspect of the invention, there is provided a method for harmlessly decomposing a chlorinecontaining substance contained in industrial waste, which comprises charging the industrial waste into a meltingrefining furnace so as to melt and refine the industrial waste at 1100'C or higher and, at the same time, thermally decompose the chlorine-containing substance in the furnace.

According to another aspect of the invention, there is provided a method for harmlessly decomposing a chlorine-containing substance contained in industrial waste, comprising the steps of:

(a) separating the chlorine-containing from the industrial waste; and (b) charging the industrial waste from which the chlorine-containing substance has been separated, by itself or together with the separated chlorine-containing substance, into a melting- refining furnace so as to melt and refine the industrial waste at 1100'C or higher and, at the same time, thermally decompose the chlorinecontaining substance in the furnace.

In one embodiment of the invention, after step (a), the industrial waste from which the chlorine -containing substance has been separated is washed or dried at 500'C_ substance or higher, or is washed and then dried at 500C or higher, prior to being charged into the melting-refining furnace.

In another embodiment of the invention, af ter step (a), the industrial waste is disassembled into a case, iron parts and copper parts, which are then washed or dried at 500'C or higher, or washed and then dried at 5OO'C or higher, prior to being charged into the meltingrefining furnace.

Alternatively, after step (a), the industrial waste from which the chlorine-containing substance has been separated is washed or dried at 500'C or higher, or is washed and then dried at SOO'C or higher, and thereafter the industrial waste is disassembled into a case, iron parts and copper parts prior to being charged into the melting- refining furnace.

According to a further aspect of the invention, there is provided a method for harmlessly decomposing a chlorine-containing substance contained in copying material which comprises:

charging the copying material, by itself or together with other industrial waste, into a melting-refining furnace, so as to melt and refine the industrial waste at 11000C or higher, and, at the same time, thermally decompose the chlorine- containing substance in the 25 furnace.

The melting- refining furnace is preferably heated using electric power. Examples of melting-refining furnaces useful in the -present invention include an AC arc 0 01 electric furnace, a DC arc electric furnace, a high-frequency electric furnace and a plasma melting furnace.

The melting-refining furnace should be able to operate at 11000C or higher so that a chlorine-containing substance such as PCB will be completely decomposed. Furthermore, the furnace should be provided with an appropriate oxygen-supply communicating with the interior of the furnace to thermally decompose the chlorine-containing substance.

Treatnent. of Tnclustrial waste Ilie ':li t f,1- ' 1 ri 1 i 1, 1 1 1 ls t-1 '1 1 W ' 1 's t e!. e --=I 1 T- w il t h in this, invention generally includes transformers, c,apacil()--s, and otner First-ly, the rethod.cr treating a transformer is considered. A normal transformer constitutes a soft-steel case of about 20 wt% of tne total weight of the transformer, a silicon-steel core of about 28 v;t%, and copper p:irts, such as coils, of about 1,2 wt%.

PCB-containing insulating oil in a transformer is 36 wt% of the total weight of the transformer, and consists essentially of 60 wt% PCB and 40 i.jt% trichlorobenzene. Additionally, 4 wt% of the total transformer weight consists of paper, synthetic gum and the like. A small transformer is 100 kVA or less and a large-sized transformer is 100 kVA or greater. The total weight of a 100 kVA transformer is about 1250 kg and the weight of insulating oil conlained t-lier,,iii is about 290 kg. The 112-119 1 Ah weight of a 500 kVA transformer is about 3800 kg and the weight of the insulating oil is up to 940 kg. It is possible to re-use the soft-steel parts, the silicon-steel parts and the like as scrap for steel. Copper is, however, undesirable in steel because the presence of copper in high amounts usually causes hot cracking. Therefore, when a large-sized transformer is being used as scrap for steel, it is desirable to remove the copper parts from the transformer after the PCB-containing insulating oil has been removed. Further, when there is a large amount of insulating oil in a transformer, it should be extracted from the transformer in advance and stored separately.

For a small transformer, after the insulating oil has been extracted, the insulating oil remaining in the crevices of the iron-core and the like is washed away with a solvent, such as kerosene or the like. The transformer is then dried in a drying furnace at 5000C or higher, disassembled when necessary, and used as scrap- Fo r a large-sized transformer (weighing 200 kg or greater) after the insulating oil is extracted, the transformer is disassembled into a case, an iron-core and copper coils. The components are independently oil-washed and dried in a drying furnace at 5000C or higher. A temperature of 5000C or higher makes it possible to vaporize PCB, which has a boiling point of between 3000C and 4000C.

The case and the iron-core which are mainly made of steel can be used as scrap for steel. Similarly, the coils and the like which are mainly made of copper can be used as scrap for copper refining. It is also possible to re-use the copper-containing scrap from a transformer, for example, as roadbed material by reclaiming it in granular form.

Secondly, a chlorine-containing capacitor is considered. There are different-sized capacitors.

112719_1 However, a capacitor generally comprise a case made mainly of soft steel constituting 16 wt%; a PCB-containing insulating oil constituting 44 wt%, insulating paper constituting 23 wt%, aluminum foil constituting 14 wt%, other metals constituting 2 wt% and glass constituting I wt% of the total weight of the capacitor.

The weight of a capacitor with a 100 kVA capacity is 68 kg, while the weight of a transformer with an identical 100 kVA capacity is 290 kg. Thus a capacitor is substantially smaller than a transformer with the same capacity. Therefore, a capacitor from which insulating oil was extracted can be used as a steel-based scrap material without any additional treatment. Thus, after the extraction of the PCB-containing insulating oil, a capacitor can be used, as it is, asscrap for steel.

In addition to the chlorine-containing industrial -waste mentioned above, the examples of chlorine-containing industrial waste include copying ink, transfer papers and I Ls of these articles are not as thc I il-e. Th PCB-conte5'1 high and it is possible to easil,-,, decompose these articles thermally by charging them directly into the metal melting-refining furnace wherein heat is provided electrically. Furthermore, the process of the present invention is suitable for harmlessly disposingof other harmful articles, such as used hypodermic needles, by charging them directly into a metal melt-refining furn ce.

The Thermal Decomposition of a Chlorine-containing Substance The thermal decomposition reactions of PCB, a typical chlorine-containing substance, can be illustrated as follows by using trichlorobiphenyl as an example.

C12117C13 -1- 1302 12C02 + 311C1 + 21120 55.110 kcal/kg C12117C13 + 702 12C0+ 311C1. + 211,0 112719 1 AH2 = 2382 kcal/kg When the partial pressure oE oxygen is sufficiently high, the thermal decomposition reaction of PCB proceeds in accordance with the first equation. Whereas, when the partial pressure of oxygen is low, the thermal decomposition reaction proceeds in accordance with the second equation. The thermal decomposition reactions of tetrachlorobiphenyl and pentachlorobiphenyl proceed s imilarly. These reactions also require oxygen in equivalent quantities as trichlorobiphenyl.

it is generally kno,;,,n that the thermal decomposition of PCBs occur within 1 second at a temperature of 11000C or higher. Therefore, the te-,--i)peratire within the furnace should be 11000C or hIgher, a suff icient of oxygen supplied for the tnerr-,ai ciec::,-,rpos 1 r_ ion reacr-lon of PC-B Lo r)roc-ee,-,-1 in a metal furnace. The following section describes the decom.position reaction in a DC arc electric furnace, a typical electri furnace.

For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to t h e accompanying drawing, as fC'lOWS:

FIG. 1 shows a schematic diagram of a DC arc electric furnace adanted for the im;:)lementation of the present invention, and assOC4ated treatment systems for the wastegas and waste-water discharged from the furnace.

Referring to the drawing, the DC are electric furnace is provided with electrodes 6, 12 electrode 6 having a gas seal 63 to prevent the furnace gas from leaking through the gap between the furnace lid 4 and the electrode 6. An inert gas, e.g. nitrogen, can be used for sealing.

with Furnace lid 4 and furnace body 2 consisting of furnace shell 201 and furnace lining 202 are further provided with a water sealing device 41 also to prevent gas leakage. Preferably, the gas pressure inside the furnace is kept at a negative pressure of 0 to -10 mmAq relative to the atmospheric pressure during operation to prevent leakage.

Unlike- cori,.,cntioral electric-- furnaces, this electric furnace is provided with a tunnelshaped scrap charge hole 8, having double- dcc,-t-z! 82. P-,4 to leak37e of cross section of the scrap charge hole 8 furnace gas. The may be circular or square.- ". tap hole '_0 is iocate;1 at the bottom of the rurnace so that the relea--,f, cE steel. can be accomplished j t 1),:, t 1-i)Ding Ihe furnace body.

luel 61 Ccr scrap and a j Cr- hI-,- ch 1 or ine-conta i n i ng subs ta nce. s into the furnace to therr-nal ly decompose these si'L3Gcarce--.

F1tke 14 is furnace gas into a 1 is -le fkirr)ac-e gas ^ 21:2 1 i cl + to 1 ead the- secondarv 'ccr-,,bust-ion section 36 wherein.

completely burnt. Tn c,-ornt-letel, 1,12 p - r, d n e e, Ilie t-cii)per'a ture in the secondary combustion section 16 is maintained at 110011C or higher, preferably at. 1,1,500C or higher.

as iiecc-ssar.,, fue-l liquid (e.g. PC13 separated a,-esprayed into secondary fuel burners 15 and 15'. Th e 75 vol% N,, about 15 to 18 about 0.03 vol% CO.

from llct.-coiit:aininq articles) cornibustion section 16 through furnace gas contains about 70 to vc)l% 0,, about 3 to 5 vol% M, The capacity of the flue 14 and the capacity of the secondary combustion section 16 are designed so that the residence time of the furnace gas in the flue and the secondary combustion section is at least 1 second or longer, preferably 2 seconds or longer so that the t chlorine-containing gas (e.g. PCB) in the furnace gas is completely decomposed. one or more venturi scrubbers 18, 19, are connected to the secondary combustion section to cool the furnace gas to 500C or lower.

To provide a waste-gas treatment system, the electric furnace is equipped with a mist separator 28, a gas heater 30, a bag filter 32 and an activated-carbon absorber 34.

Chlorine, 11C1 or the like in the waste-gas is completely removed by this waste-gas treatment system. The activated-carbon absorber 34 is provided to completely remove dioxin, if produced, whereas the waste-gas, mainly 11, and CC), are discharged by an exhaust ventilator 35 through stack 36 into the air.

The waste-water treatment system further includes a waste-wat&r flter 20, an activated-carbon -bsorber 22 a neu-ralizatio bath 21t and a thickener recovery of the cooling water Tl,.e 1111CL ccntain&_"1 i, LA,,_ in the neutralization bath 24 dioxin or tne like --re captured 1y the activatedcarbon absorber 22.

The venturi scrubbers also serve as primary and secondary dust collectors. In the venturi scrubbers the waste-gas heated to 1100cC or higher is rapidly cooled down to 750C or lower by spraying cooling water to prevent the production of dioxin. Furthermore, at the same time, the major portion of HCl contained in the waste-gas is dissolved and absorbed into the cooling water.

Cooling water is further sprayed into the waste-gas in the secondary dust collector, to completely absorb the 11C1. The 11C1 containing water is neutralized in a neutralization bath and recovered by thickener 26.

The of the present invention is advantageous in that the transformers and capacitors can be charged L. n This systern provides for the used in the venturi scrubber. cooling water is neutralized and toxic by-products such as 112719 1 intoan electric furnace as scrap for steel while at the same time PCB-containing insulating oil and the like, previously separated from those transformers and capacitors, can be charged into the electric furnace during the refining process and thermally decomposed.

This makes it economical to dispose of PCB and the like harmlessly. Additionally, the PCB-contaminated activated-carbon absorbers used in the course of drying the transformers and the like can also be charged into the electric furnace, whereby the PCB which they contain can be harmlessly anj dis-posed 01f.

Pis stated above, the present invention has been i 11 u s t r a t e d with refennce to MB, a typical chlorine-containing industrial waste. The present is also useful to harmlessly decompose other chlorine-containing suustdiices such as v-i-nyL chloride, shredder dust containing vinyl chloride, chloro-nitropheron (CIIP) chlorine-containing agricultural chemicals (e.g.

l-richic)rcbenzen, vinylidene chloride, benzyl chloride, benzoyl chloride, benzylidene chloride and the like.

Other types of electric furnaces, such as an AC arc electric furnace, a high-frequency electric furnace nr a plasma melting furnace may also be used instead of the DC arc electr-c furnace illustrated above. These electric furnaces can perform the same melting and refining operation.

T--- Exa,-Ples i Un.

1 In a 100 ton DC arc electric furnace, the transformers, capacitors and the like from which chlorine-containing substances had already been removed as described hereinbefore were melted and refined as scrap. 12 charges for rneditirn carbon steel. (0.1 to 0.2 %) were 112719 1 performed.

Combination Charged (Ch):

Cold pig iron Scraps (transformers and capacitors from which chlorine-containing substances were removed) ton/ch ton/ch Carburizer 1000 kg/ch melting-refining period:

minutes (1 ch) c 1 Amount of waste-gas:

150() 1n3/M (90,0OC) 11M3/ in ch) Amount of the cooling-water used in the uenturi SCrUbber which also serves as a dust-collector:

ton/charge During the meltingrefining operations of the 12 heats, 1 to 6 tons per charge of chlorine-containing insulating oil was added, and the 11C1 concentration of the waste-water from the electric furnace was calculated. The results of this calculation are listed in Table 1. The cnlorne content of the chlorine-containing insulating oil A was lCj wt--Each of the experinnients shown in Table 1 was 1 perforned through the use of 2 charges at every level n. the charge amount of the insulating oil. The 11C1 concentration of the waste-water was that of the waste-water which was yet to enter the neutralization bath. As shown in Table 1, the TIC] concentration of the waste-water was low enough to be completely neutralized in the bath.

112719 1 f' 1 Table 1 charge amount amount of HCl HCl 11C1 of insulating produced concentra- concent oil tion (%) in ration ton/ch ton/ch ch the furnace in the jjM31 gas of the waste electric water furnace 1.0 0.106 65.2 0.072 0.05 2.0 0.212 130 0.144 0.10 3.0 0.318 195 0.216 0.15 4.0 0.425 261 0.290 0.21 5.0 0.531 326 0.362 0.26 6.0 0.434 0.31 11C1 concentration (%) amount of HCI produced X 100 in the furnace gas = amount of furnace gas of the electric furnace produced 1 1(--] (%) - amount of 11C1 pnoduced [tonlcn X 100 in waste-water amount of the waste-water [ton/chl amount of furnace gas produced in the electric Lurnace 9OOC) ITM3/ of 1 ch (1500 IIM3 /min x 60min/ck) amount of waste-water = 200 ton/eh 1127191 EXAMPLE 2 r - k Experiments were conducted in order to check the degree of the decomposit.ion of organic chlorine compounds and the presence of dioxin production in a DC arc electric furnace. In these experiments, a commercially available cutting lubricant, an organic chlorine compound, was charged into a 100 ton electric furnace through a liquid-waste burner 62. Tie cl-itt-ing lubricant used herein was a wateri nsoluble cutting lubricant specified in JIS K 224.1. The charge amounts of tthe cutting lubricant are shown in Table 2. Each of the experiments shown in this table was performed through 2 charges at ever,,, level of the charge amount of t.e lubricant.

i n t-,ti.-z-se e v peri ts. tr a ns former an cl, c-a,rac-Jtc,.s from whicl. slles-ar.c-es had been as wc-re charged nlc-c a:j(-, arc electric furnace as scrap,. As shown in Table 2 in which the c,-,perim.c-nt results are listed, neither organic chlorine compound nor dio-in was found in. the waste-gas, r r c -1 FLirttierr.-,re it was frr- the increase of the a,-,ct:nt of the parts and Capacitors) in Cc)rnpar,Lso:-, that ot trie operatien of the furnacce that,,r the -heat produced by the dec -rpGscompounds must have 1jeen transferred in the furnace.

11,1711) 1 the organic chlorine to the inolten steel Table 2

Experiments using a 100 tons DC arc electric furnace level charge amount detection of detection of of cutting oil organic compounds dioxin (Kg) 1 670 none none 2 1330 none none 3 2000 none none 4 2670 none none 1127191 18 -

Claims

CLAIMS:

1. A method for harmlessly decomposing a chlorine-containing substance contained in industrial waste, which comprises charging the industrial waste into a melting-refining furnace so as to melt and refine the industrial waste at 1100'C or higher and, at the same time, thermally decompose the chlorinecontaining substance in the furnace.

2. A method for harmlessly decomposing a chlorine-containing substance contained in industrial waste, comprising the steps of:

(a) separating the chlorine -containing substance from the industrial waste; and (b) charging the industrial waste from which the chlorine-containing substance has been separated, by itself or together with the separated chlorinecontaining substance, into a melt.; ng-ref ining furnace so as to melt and refine the industrial waste at 11000C or higher and, at the same time, thermally decompose the chlorine-containing substance in the furnace.

3. A method according to claim 2, wherein after step (a), the industrial waste from which the chlorinecontaining substance has been separated is washed or dried at 500'C or higher, or is washed and then dried at 500'C or higher, prior to being charged into the melting-reflning furnace.

4. A method according to claim 2, wherein after step (a), the industrial waste -from w'--.---h the chlorinecontaining substance '-,.as been senara:ed is disassembled into a case, J-ron r,-mrtis and copper nar's w".---h are then washed or dried at SOCC or higher, or washed and then dried at SOCC or higher prior to being charged into the melting-refining furnace.

5. A method according to claim 2, wherein after step (a), the industrial waste from which the chlorinecontaining substance has been separated is washed or dried at 500'C or higher, or is washed and then dried at 5000C or higher, and thereafter the industrial waste is disassembled into a case, iron parts and copper parts prior to being charged into the meltingrefining furnace.

6. A method for harmlessly decomposing a chlorine-containing substance contained in copying material, which comprises:

charging the copying material, by itself or together with other industrial waste, into a meltingrefining furnace, so as to melt and refine the industrial waste at 11000C or higher, and, at the same time, thermally decompose the chlorine-containing substance in the furnace.

7. A process according to any preceding claim, comprising heating the melt ing- refining furnace using electric power.

8. A method according to any preceding claim, wherein the meltingrefining furnace is an AC arc electric furnace, a De arc electric furnace, a highfrequency electric furnace or a plasma melting furnace.

9. A method according to any preceding claim, wherein the chlorinecontaining substance is a polychlorobiphenyl (PCB)

10. A method for harmlessly decomposing a chlorine-containing substance present in industrial waste, substantially as hereinbefore described with reference to the accompanying drawing.

11. A method for harmlessly decomposing a chlorine-containing substance present in industrial waste, substantially as described in either of the foregoing Examples.