EP0489910A4

EP0489910A4 - Process for incinerating solid wastes and a process for treating solid wastes and a process for treating gases generated through incineration of these wastes

Info

Publication number: EP0489910A4
Application number: EP19910914869
Authority: EP
Inventors: Nobuyasu Hasebe; Nobukatsu Hasebe
Original assignee: Individual
Current assignee: Individual
Priority date: 1990-06-27
Filing date: 1991-06-27
Publication date: 1993-07-21
Also published as: JP3094449B2; WO1992000491A1; AU8390591A; CA2065359A1; JPH06503872A; EP0489910A1; CA2065359C

Abstract

The present invention relates to a process for incinerating burnable wastes, such as plastics, accompanied by treating the gases generated through incinerating burnable wastes, characterized in that the energy of an explosive is used to initiate the combustion of the said burnable wastes, such as plastics embedded in the land, thereby simultaneously forming combustion chambers for primary combustion, supplying fuels (1) and an oxidizing gas (2) into said chambers whereby incineration is carried out while discharging gases (3) generated through incineration to above the surface of the land, subjecting the said gases generated through incineration to oxidation in the presence of a catalyst (4), whereby the toxic gases such as CO, COC12, and dioxin contained therein are converted into CO2 H2O, HCl, and SOx, which are then generally treated.

Description

PROCESS FOR INCINERATING SOLID WASTES AND A PROCESS FOR TREATING SOLID WASTES AND A PROCESS FOR TREATING GASES GENERATED THROUGH INCINERATION OF THESE WASTES

DETAILED DESCRIPTION OF THE INVENTION

The invention relates to a process for inciner¬ ating solid wastes, such as plastics, and a process for treating gases generated through incinerating these wastes. Over the last several decades an increasing eco¬ nomic base, and increasing urbanization, has caused a corresponding increase in the volume of solid wastes. Additionally, the properties of these wastes have be¬ come more varied, and now include a variety of plastic and chemical products containing a diverse cross sec¬ tion of toxic and harmful products. Generally, either burning or embedding (burial) is applied to treat such wastes, resulting in various complicated environmental and regional social problems. This is especially true in treatment by embedding, making the establishment and expansion of landfills increasingly difficult because of higher land utilization rates, and resistance of res¬ idents near the landfill. Meanwhile, the problem in¬ creases year-by-year with the growing volume of solid waste.

Among solid wastes the amount of plastics has increased dramatically due to the increased use of these substances in home appliances and automobiles, and as a packaging material for fast foods, disposable diapers and medical wastes. Treating these wastes is especially difficult because they are either slow to degrade, or are completely non-biodegradable, thus shortening the life of a landfill. Such biodegradation that does occur creates its own problems through the release of component elements, such as chlorine. Treatment of these wastes by incineration is even more hazardous due to the release of these hazardous materi¬ als in the form of air pollution. More recent research has focused on processes for manufacturing biodegrad- able plastics which can be degraded by microorganisms present in the soil. However, many problems are yet to be solved with respect to the effectiveness of these new plastics.

In light of the aforesaid situation, the inven- tor has focused on the fact that the plastics per se are burnable, and other burnable wastes still exist in an undegraded condition, intending to solve the problem by incineration. After conducting extensive research, the inventor has thus accomplished the present process. The first aspect of the present invention re¬ lates to a process for incineration of burnable waste, characterized in that the energy of an explosive, and of burnable wastes, combustible gases, oil and fat prod¬ ucts and refined fossil fuels, is used to initiate the combustion of the said burnable wastes, such as plas¬ tics, embedded in a landfill while simultaneously form¬ ing a combustion chamber; supplying fuels and an oxidiz¬ ing gas into said chamber whereby combustion is carried out while discharging the gases generated through incin- eration to the surface of the land.

Another aspect of the present invention re¬ lates to a process for treating gases generated through incinerating the burnable wastes, characterized in that the gases generated through the incineration of burn- able wastes are oxidized in the presence of catalysts. Thereby toxic CO, C0C1₂ and dioxin as chlorinated bi- phenyl, and sulfur compounds such as thiophene, thiols and carbon disulfide etc. , are altogether converted into C0₂, H₂0, HC1, and SO_χ, etc., which are then treated separately. The wastes applicable to the present invention include those of plastics, rubbers, paper, cellulose, wood, oils and lipids, and waste petroleum products, medical wastes, agricultural wastes and wastes from the food processing industry. In particular, wastes from the medical industry and facilities are increasing in volume and diversifying in kind, and are most often in¬ cinerated or disposed of underground, sometimes without proper treatment. These burnable wastes are placed flat on the surface of the land or into an excavated land¬ fill. These wastes are piled up to desired depth by means of earth-moving equipment or other mechanical de¬ vices, and covered with soil; mechanical force is then applied downwards to achieve embedding. A series of pipes are sunk into the embedded wastes (fig. 1) includ¬ ing respectively: a fuel conduit pipe 1 for supplying fuel from the surface; an air conduit pipe 2_. for supply¬ ing an oxidizing gas; and a number of discharge conduit pipes 3. for discharging the gases generated through in- cineration. The aforesaid conduit pipes 1 , 2_., and 3_. may be set up by sinking a shaft vertically in the ground by a device such as an auger, the diameter of the shaft being larger than those of the conduit pipes. A casing is then set into the shaft and the conduit pipe is in- stalled into the casing. Both conduit pipes 1 and 2 may be installed in a single casing. There may be many such pipes and casings. Fuel conduit pipe 1 and air conduit pipe 2 are, for example, set up at approximately the center of the embedded waste, and within a few meters of each other. At the front opening of the fuel conduit pipe _ the pipe is provided with a nozzle which functions to control the jet-angle of the fuel or mix¬ ture of the fuel and air, whereby the direction of incineration of the wastes can be controlled. Similar- ly, at the front end of the air conduit pipe 2_. there is a nozzle which serves the same function of controlling the direction of incineration, and adjustment of the angle may be coordinated with the nozzle on fuel con¬ duit pipe 2-_r ^or made independently or the adjustment may be set in a single fixed condition. Also, if de¬ sired, piping may be connected respectively with fuel conduit pipe 1 and air conduit pipe 2. so as to treat sewage, drainage water (grey water) or steam generated from the landfill. Prior to injection this sewage, and/or waste water must be treated to remove metals, especially heavy metals in the form of hydroxides and sulfides of metals etc. , while organic materials are decomposed through combustion. The number and position¬ ing of conduit pipes 3. are defined by the size of the area to be treated, local topography, and considera¬ tions of controlling the direction of combustion.

In cases in which a smaller quantity of wastes is incinerated, a circular or equilateral polygon scheme may be adopted (Figure 1) . In this scheme, fuel conduit pipe 1 and air conduit pipe 2. are sunk approxi¬ mately at the center of the embedded wastes and a num¬ ber of discharge conduit pipes are embedded on the cir¬ cumference of concentric circles or on the circumfer¬ ence of an equilateral polygon, so that the combustion proceeds with a shape approximating an expanding circle or equilateral polygon radiating from the origin. In variations of this scheme, the origin may be located off the center or near a corner of a site and incinera¬ tion may proceed in a shape approximating an expanding segment of a circle or polygon. Each conduit pipe 3_ may be connected to each other conduit pipe, and all are eventually connected to the incineration-treatment apparatus for treating gases from incineration.

Where a large quantity of wastes is to be in- cinerated, it is desirable to adopt a linear scheme for the placement of conduit pipes (Figure 3). In this scheme, a primary line on which fuel conduit pipe 1 and air conduit pipe 2. are sunk. A secondary line, which is approximately parallel to or at an angle to the primary line, an a tertiary line that connects the fuel conduit pipe 1 and air conduit pipe 2 and a conduit pipe 2 on the secondary line are established. A number of dis¬ charge conduit pipes .3 are sunk on the primary, second¬ ary and tertiary lines. Each of these conduit pipes is connected to the adjacent pipes. The primary line can have more than two secondary lines on either side or both sides. Between the primary and secondary lines a number of discharge conduit pipes 3. may be sunk in a grid pattern with each of the conduit pipes connected to adjacent pipes. All of the discharge conduit pipes are eventually connected to the incineration treatment apparatus for treating gases from incineration.

In actual operation, a number of factors need to be considered with regard to placement of conduit pipes. Schemata described above need to be modified or combined to accommodate idiosyncracies of each incinera¬ tion site.

Now an embodiment of gases from incineration- treatment-apparatus 4. is illustrated in fig. 2. In said fig. 2: 5 is a combustion chamber; β_ is a charge pipe for gases from incineration which is connected to com¬ bustion chamber 5 ; 7_ is a catalyst-fill-layer which is connected to combustion chamber 5_., and is connected to the side of catalyst-fill-layer 8.; 9. is an oil-supply- pipe connected to aforesaid charge pipe €>, and is pro¬ vided with a flame nozzle; .10 is an air-supply-pipe connected to charge pipe 6. for auxiliary combustion; .11 is an air blower attached to the said air-supply-pipe 10. In the gases from incineration-treatment-apparatus 4. with the aforesaid structure, gases from discharge conduit pipe 3_. is introduced to combustion chamber 5_. When the reaction starts, auxiliary fuel or landfill gas is used to keep the catalyst within an active temperature range. For this purpose, fuel (liquid or gas) or landfill gas is introduced via pipe 9., and mixed with air, which may supplied via pipe .1(3 or independently to pipe 9., for combustion, whereupon the heat generated through combustion is passed through the wall of charge pipe .6 which is thus directly or indi- rectly heated whereby on one side the temperature of the catalyst-fill-layer is maintained at a specified temperature and on the other side the temperature of the gases from incineration is elevated. The gases from incineration are then introduced into the catalyst- fill-layer l_ so as to be subjected to oxidative decom¬ position such that the toxic components are converted respectively to carbon dioxide, water, hydrogen chlo¬ ride, and depending on what is desired, sulfur is con¬ verted to sulfur dioxide or hydrogen sulfide; with both of the latter two gases being treated separately, and then being converted to nontoxic salts or being recon¬ verted to sulfur before being discharged to the atmos¬ phere. In order to control the temperature of the cata¬ lyst-fill-layer 7, a temperature detector is placed therein, whereby through the sensor of the said tempera¬ ture detector the amount of oil, fuel, or gases ungra¬ ded in the landfill to be supplied through oil-supply- pipe 2-0. can be adjusted; additionally, air blower 11 attached to air-supply-pipe 10 can be adjusted directly or a ventilation pipe connected to air blower .11 may be set up whereby through the action of the valve of the ventilation pipe adjusted to the signal switch of the temperature sensor, the cooling effect can be in¬ creased. Further, at the front end of charge pipe 6. there is set up a cone so that the gases from incinera- tion can be readily diffused, resulting in their easy introduction into catalyst-fill-layer 7.

The catalyst to be filled into the aforesaid catalyst-fill-layer 7_ is the oxides of vanadium, cop- per, lead, cobalt and cadmium whose basicity is strong¬ er than that of vanadium oxide. As an alternative, a mixture of vanadium oxide and potassium persulfate, to which an alkal hydroxide has been added, can be used. The oxides which act to destroy the benzene ring togeth- er with its side chains are preferably mixed with por¬ ous or non-porous carrier(s) . Generally, it is prefer¬ able that porous carriers in powder form, such as silica gel and titanium dioxide, with high specific surface areas be made into shaped carriers for use. Furthermore, in the case of a supported catalyst, it is preferable that the carrier be made of C.-AI₂O₃, SiC, aluminum silicate which are low in specific sur¬ face area and are non-porous with a pore size of 2.20 mm. In addition, the temperature of the catalyst-fill- layer adjacent to the inlet through which the gases from incineration enter should be sufficiently elevated to intensively carry out the oxidative decomposition, expecting that a desired oxidation degree can be reached. The process for the manufacture of the cata- lyst may utilize impregnation, concentration-to-dry- ness, baking, melting with a proviso that the catalyst should be rendered active at a temperature above 200 degrees centigrade.

The primary combustion of the burnable wastes embedded under the land is carried out at an area be¬ neath fuel conduit pipe .1. That is, for example, through fuel conduit pipe 1 , while injecting combusti¬ ble petroleum products such as LPG, heavy oil, light oil, and heating oil, or landfill gas, into the wastes and carrying out ignition, or placing an explosive in the wastes and igniting it, so that the burnable wastes are ignited and a combustion chamber necessary for for primary combustion of burnable wastes is created. For the aforesaid explosive, trinitrophenol, trinitrotolu- ene, glycerin trinitrate or their derivative products may be used. Following creation of the combustion cham¬ ber a flammable liquid or gas is fed through fuel con¬ duit pipe 3., and an oxidizing gas — such as oxygen —, an oxygen-containing gas, or air is supplied through air conduit pipe 2. so that the wastes are kept in a com- bustive state. Landfill gas (i.e. methane) can be drawn off via pipe 12, and fed to fuel conduit pipe 1 to supplement, or replace, the initial fuel being used. Further, in carrying out combustion, the combustion rate can be controlled by regulating the amount of oxidizing gases, with concurrent use of water or steam being feasible. In accordance with our experience, an alkali metal carbonate such as sodium carbonate, an alkali earth metal carbonate such as calcium carbonate, magnesium carbonate, or an alkali earth metal bicarbon¬ ate such as calcium bicarbonate is also very effective — when sprayed in the form of a suspension in a liquid fuel — at removing from the burnt products all chlor¬ ine-containing, or sulfur-containing compounds in the form of inorganic chlorides or sulfates. These above mentioned carbonates reduce, on a large scale, the amount of poisonous chlorides, such as phosgene, gener¬ ated upon the combustive decomposition of such plastics as polyvinyl chloride. Further, combustion direction can be controlled by either controlling the amount of the gases-from-incineration discharged from discharge conduit pipes 3_ or by combining said measures using temperature recorders and electrothermography.

The gases from incineration are discharged to the surface. At this time, a thermal imaging method using an infrared scanning device can be applied to de¬ tect the size and scale of the combustion area, togeth¬ er with its moving directions whereupon new discharge conduit pipes 3. can be set up. The gases from incinera- tion discharged through discharge conduit pipe 3_ are introduced into incineration-treatment-apparatus 4_. where such toxic gases as carbon monoxide, phosgene, and dioxins, and organic and inorganic sulfur compounds and sulfons are converted into carbon dioxide, water, hydrogen chloride, sulfur dioxide, and hydrogen sul- fide, etc. , which, after being treated altogether are discharged into the atmosphere in the form of clean non- toxic gases. In addition, allyl, aryl chloride, which is possibly contained in the combustion gases, having been subjected to catalytic oxidation may be treated with steam once or twice so as to convert said allyl, aryl chloride into very simple inorganic compounds

(i.e. carbon dioxide and hydrogen chloride) . In case a power failure occurs to the incineration-treatment-appa- ratus 4-, the supply of air through air conduit pipe 2. will be cut off immediately, thereby resulting in automatic cessation of combustion. As an additional safety measure, at this time, the introduction of water or C0₂ into the combustion chamber could be utilized. At the end of the incineration treatment of wastes, fuel conduit pipe 1 , air conduit pipe 2. and discharge pipe 3. may be drawn out, while the combustion area formed under the surface may be rolled flat and uniform with pressure for the next embedding treatment. [ACTION]

In the present invention, the energy of an ex¬ plosive or petroleum products such as LPG, heavy oil, light oil and heating oil, or landfill gas, may be uti¬ lized to initiate the combustion of burnable wastes, such as plastic, embedded in a landfill, thereby simul¬ taneously forming a combustion chamber for primary com¬ bustion. A fuel and an oxidizing gas are supplied into the said chamber whereby combustion is carried out while discharging the gases from incineration through additional conduits. By such a simple and accurate man¬ ner, incineration treatment of wastes can be carried out on a large scale. Further, toxic components con- tained in the gases from incineration discharged to the surface are oxidized in the presence of a catalyst whereby toxic components, such as carbon monoxide, phos¬ gene, dioxins, and organic and inorganic sulfur com¬ pounds such as carbon disulfide, carbonyl sulfide, thio alcohols, olefin polysulfides, and sulfons, are convert¬ ed into carbon dioxide, water, hydrogen chloride and SO_χ, which after being generically treated are dis¬ charged to the atmosphere in a clean and nontoxic form.

[EFFECT OF THE INVENTION)

The present invention is constituted as stated above, according to the present invention based on which it is not necessary to set up, as before, an in¬ cinerator to treat burnable wastes such as: plastics, rubbers, wooden materials, oil and lipids, cellulose, waste petroleum products and medical wastes. These mate¬ rials can be simply, conveniently and safely incinerat¬ ed on a large scale. Meanwhile, the combustion chamber formed after incineration treatment may be rolled uni- form with pressure for its next use as a landfill, thus extending the life of the landfill. Also, gases gener¬ ated upon incineration treatment can be oxidized in the presence of a catalyst to convert them into clean, and completely nontoxic gases, without environmental prob- lems caused by conventional incineration treatment. The following examples serve to illustrate the present invention, but not to claim 7, the scope of the present invention. Example 1: Fuel conduit pipe 1 and air conduit pipe 2., provided with nozzles for which the spray angle could be adjusted, were respectively set up near the center of embedded wastes from the surface. Meanwhile, four discharge conduit pipes 3. were set up on the circumfer- ence of a circle, with said two conduit pipes 1 and 2. as its center at a radius of 20 meters, such that the pipings from said conduit pipes 3. were connected to each other. Then the wastes were subjected to incinera¬ tion treatment under the following conditions:

Explosive used (trinitrophenol) : 5 kg

Fuel (C grade heavy oil with 5% sulfur) : 1 kg/hr

Rate of gaseous fuel supply : 0 NM³/hr

Rate of air supply :20 NM³/hr

Alkali used : 0 kg/hr

The gases from incineration thus produced were discharged through conduit pipe 2, and were then treat¬ ed in the gases-from-incineration-treatment apparatus 4. After the embedded wastes had been incinerated out, conduit pipes 1. 2 and 3. were withdrawn, and the combustion cavity generated under the land was rolled uniform by means of earth moving equipment.

Example 2:

Fuel conduit pipe 3., air conduit pipe 2., and discharge conduit pipes 3._r were set up in embedded plas¬ tic wastes in a manner similar to that of Example 1. Incineration treatment was carried out under the follow- ing conditions, and the gases from incineration thus generated were treated in the gases-fro -incineration- treatment-apparatus 4..

Explosive used (trinitrophenol) : 5 kg Fuel (C grade heavy oil with 5% sulfur) : 1 kg/hr Rate of gaseous fuel supply : 60 NM³/hr

(gases generated in the landfill)

R:aattee ooff aaiirr ssuuppppllyy : 40 NM³/hr Alkali used (CaC0₃) : 10 kg/hr

Example 3:

Fuel conduit pipe 1 , air conduit pipe 2., and discharge conduit pipes 3. were set up in embedded plas¬ tic wastes in a manner similar to that in Example 1. Incineration treatment was carried out under the follow- ing conditions and the gases from incineration thus gen¬ erated were treated in gases-from-incineration appara¬ tus 4..

Explosive used (trinitrophenol) : 2 kg Fuel (C grade heavy oil with 5% sulfur) : 0 kg/hr Rate of gaseous fuel supply :100 NM³/hr

(gases generated in the landfill)

Raattee ooff aaiirr ssuuppppllyy : 60 NM /hr Alkali used (MgC0₃) : 10 kg/hr Example 4 :

Fuel conduit pipe 1, air conduit pipe 2,_r and discharge pipes 3., were set up in embedded plastic wastes in a manner similar to that in Example 1. Incin- eration treatment was carried out under the following conditions and the gases from incineration thus generat¬ ed were treated in the gases-from-incineration-treat- ent apparatus 4..

The result of analysis on the gases from incin¬ eration thus generated in Examples 1 through 4 are shown in Table 1.

Table 1 Analysis of the Gas From Incineration

Note: + denotes approximately 10 ppm

The results obtained by treating the gases from inciner¬ ation generated in Examples 1 through 4 with gases- from-incineration-treatment apparatus 4. are shown in Table 2 and Table 3. For Table 2 the gases were treated at the cata¬ lyst temperature of 200 degrees centigrade and with space speed of 1000 hr^"1 (volume of the reaction gas- es/hr/volume of the catalyst, i.e. the reciprocal of contact time) . For the catalyst, V₂0₅ - K₂S0₄ - Si0₂ - K₂S₂0₇ - S series was used in mole ra¬ tios:

K₂SO₄/V₂O₅=0.98, K₂S₂0₇/V₂0₅=2.02, ( ₂S₂0₇+K₂S0₄)/SO₃=0.55, K₂SO₄/SO₃=0.18, and for the carrier, silica gel and diatomaceous earth in ratio 5 to 1, was made into pellets of five millime¬ ters in diameter and tree millimeters in length.

For Table 3, an example of the catalyst composition in mole ratios is: κ₂so₄/v₂o₅=ι.ιo, ₂S₂0₇/V₂0₅=1.71, K₂SO₄/SO₃=0.23, K₂S₂0₇/S0₃=0.35, (K₂S₂O₇+K₂SO₄)/SO₃=0.58.

Gas was treated at the catalyst temperature of 400 degrees centigrade with space speed of 2000 hr^-1 and silica gel was used as carrier with powdered pumice added in the ratio five to one. The pellet size was the same as above. At lower temperatures emission of S0₃ from the catalyst series decreases and the acidity of the catalyst increases, so that the potential becomes decreased. Therefore, when the sulfur content of the sample gas is high, the sulfur content was removed and the amount of total S0₃ was adjusted before use. Table 2 Analysis of the Gas Before and After Treatment

Example of Catalyst Composition for Table

Table 3 Analysis of Gas Before and After Treatment

Example of Catalyst Composition for Table 3

Analysis of Example of Carrier for Table 3

Brief Description of the Drawings

Fig. 1 depicts an arrangement status of fuel conduit pipe 1 , air conduit pipe 2. and discharge con- duit pipes 3..

Fig. 2 depicts an arrangement status of gases- from-incineration-treatment apparatus 4..

Fig. 3 depicts an arrangement of conduit pipes that is an alternative to that shown in Fig. 1.

In Fig. 1, Fig. 2 and Fig. 3, the numerals l to LI have the following meanings.

1. . . fuel conduit pipe

2. . . air conduit pipe

3.. • • discharge conduit pipes

4.... gases-from-incineration-treatment apparatus 5.... combustion chamber

6.... charge pipe

7_. . . catalyst-fill-layer

8.... side of catalyst-fill-layer

9_.... oil-supply-pipe .10_.... air-supply-pipe

11... air blower

12... discharge conduit pipe

Claims

What we claim is :

1. A process for incineration treating burn¬ able wastes, characterized in that the energy of an ex¬ plosive is used to initiate the combustion of the said burnable wastes such as plastics embedded in the land, simultaneously forming a combustion chamber for primary combustion, supplying fuels and an oxidizing gas into the said chamber, whereby incineration is carried out while discharging the gases generated through incinera¬ tion to the surface of the land.

2. The process according to claim 1, wherein the said combustion chambers are formed to supply liq¬ uid or gaseous fuels through a fuel conduit pipe and to supply an oxidizing gas such as oxygen, oxygen contain- ing gas, and/or air.

3. The process according to claim 1, wherein sewage and drain water generated in a landfill is pread- justed for ph, then treated with landfill gas so as to precipitate and separate metals, especially heavy met- als in the form of hydroxides and metal sulfides, and thereafter the landfill gas is supplied to a combustion chamber as a gaseous fuel through the fuel conduit pipe.

4. The process according to claim 1, wherein at the front end opening of the fuel conduit pipe, and at the front end opening of the air conduit pipe, there is set up a nozzle respectively with which the jet an¬ gle of the fuel, and of the air, are adjustable, or each of which is controlled at a single fixed condition respectively. 5. The process according to claim 2, wherein landfill gases or gases generated through the incinera¬ tion of burnable wastes are used as gaseous fuels.

6. The process according to claim 1, wherein a suitable number of discharge conduit pipes through which the gases from incineration are discharged to the surface of the land, and which are connected to each other via pipings, and are set up in such a manner that combustion, initiated in a primary combustion region in the combustion chamber, will proceed toward the discharge conduit pipes in the shape of an expanding circle, polygon, or a segment of a circle or polygon.

7. The process according to claim 1, wherein an infrared sensor is used to detect the size and the moving direction of the combustion chamber which lie under the land, whereby more than two discharge conduit pipes are set up through which the gases from incinera¬ tion are discharged.

8. A process for treating the gases generat¬ ed through incineration of burnable wastes, character¬ ized in that the gases generated through incinerating wastes are subjected to oxidation in the presence of catalysts, whereby such toxic gases as CO, C0C1₂, dioxin and sulfur compounds are converted into such compounds as C0₂, H₂0, HC1, and SO_χ, which are then treated altogether and converted into nontoxic substances. 9. The process according to claim 8, wherein for the catalysts, whose carrier is mainly composed of silica or silica gel, V₂O₅-K₂SO₄-SiO₂-K S₂0₇-S series, in mole ratios: K₂S0₄/V₂0₅=0.5-3.00,

[one or more oxides of Sn, Cu, Pb, Co, Al]/V₂0₅<5, (κ₂so₄+κ₂s₂o₇)/v₂o₅=o.1-0.6, are employed to carry out complete oxidative decomposi- tion of landfill gas and gases generated through incine¬ ration of wastes at a catalyst temperature greater than 150 degrees centigrade and a space velocity of 200- 10,000 hr^"1.

10. The process according to claim 1, wherein a portion of the landfill gases is added to the gases from incineration for precombus ion.

11. The process according to claim 8, wherein the gases from incineration which have been treated with the catalyst is further treated with steam, where¬ by allyl, aryl chlorides are converted to C0₂ and hydrogen chloride.

12. The process according to claim 2, wherein sewage and grained water generated in a landfill are pretreated so as to remove metal, especially heavy met¬ al in the form of metal sulfides, which landfill gas is them supplied as a gaseous fuel through the fuel con¬ duit pipe.

13. The process according to claim 2, wherein at the front end opening of the fuel conduit pipe, and at the front end opening of the air conduit pipe, there is set up a nozzle respectively with which the jet an- gle of the fuel, and of the air, are adjustable, or each of which is controlled at a single fixed condition respectively. 14. The process according to claim 3, wherein at the front end opening of the fuel conduit pipe, and at the front end opening of the air conduit pipe, there is set up a nozzle respectively with which the jet angle of the fuel, and of the air, are adjustable, or each of which is controlled at a single fixed condition respectivel .

15. The process according to claim 6, wherein an infrared sensor is used to detect the size and the moving direction of the combustion chamber which lie under the land, whereby more than two discharge conduit pipes are set up through which the gases from incinera¬ tion are discharged.

16. The process according to claim 9, wherein a part of landfill gases is added to the gases from in¬ cineration for precombustion.

17. The process according to claim 9, wherein the gases from incineration which have been treated with the catalyst are further treated with steam, where¬ by allyl, aryl compounds are converted to C0₂, S0₂ and hydrogen chloride.

18. The process according to claim 10, wherein the gases from incineration which have been treated with the catalyst are further treated with steam, where¬ by allyl, aryl compounds are converted to C0₂, S0₂ and hydrogen chloride.