JPH0771671B2 - Method for wet oxidation of organic wastes in wastewater - Google Patents

Description

Description: FIELD OF THE INVENTION This invention relates to a method for wet oxidizing organic waste in wastewater, and more particularly to a wide range of waste treatment methods characterized by waste oxidation. .

(Prior Art) In the context of an industrial plant, a relatively large amount of waste is often generated. Here, the term waste is used as a very broad term that extends to accumulated organic waste. An example of such organic waste is sewage and muddy water discharged from urban sewage treatment facilities. Therefore, it contains a large amount of bacteria. Other materials, referred to herein by the term waste, also include a relatively wide variety of hydrocarbons. Such hydrocarbons generally include various forms of halogens, sulfur, light metals such as sodium, and the like. It also contains heavy metal ions which are metal poisons, including compounds such as lead and mercury. The disposal of this type of waste must meet a wide range of needs including the need to kill bacteria, decompose hydrocarbons, or recover various salts. Therefore, in the present invention, the term waste is intended to include substances of the types listed above. There are various other types of waste, and the mixture and ratio of various waste components are extremely wide.

One of the proposed systems for the treatment of waste of this nature (probably defined in a narrower sense) is "Supercritical Water Oxidation for Wastewater Treatment: Preliminary Study. Of Urea Destruction "(Supercritical Water Oxidation for
Wastewater Treatment: Preliminary Study of Urea Des
truction) in SAE Technical Paper 820872, 19 July 1982.
There is one written on the 20th. The same document describes a device used for a long-term space mission, which is the device shown in FIGS. 1 and 2 thereof. However, this type of device is of very limited importance, as evidenced by its use in spacecraft. Other technical documents include AC-S (AC
Environmental Science and Technology (Environmental Science)
& Technology) No. 10, Volume 16, 548A-551A, "Super Critical Fluids" (Su
percritical fluids). The same staff member as SAE magazine mentioned above participates in this document, and shows a device for handling a specific waste.

Focusing on Patents, US Patent No. 1 by Bauer
There are 3,449,247 issues. The patent shows a wet oxidation method. More recent U.S. patents include Lawless No. 3,606,999. It shows a system utilizing high pressure and continuous flow (massive). And in a more recent U.S. patent, No. 3,853 by Titmas,
There is number 759.

(Structure of Invention) The present invention is a method for treating a wide range of wastes as described above. The present invention provides an advantageous method of utilizing discarded wells. Here, the term well is hereinafter defined as a well-sealed material that does not allow waste to penetrate and damage the surrounding formations. This generally refers to a well in which cement is embedded between the surrounding formation and the casing to fix the casing and seal the well. Cement is also very often used as an insulating material. Further, the well insulation preferably forms a reaction chamber at the bottom of the well. The well has a pressure at its bottom of about 3200 psi (225 kg / cm ² ).
It is assumed to have a sufficient depth to exceed. Water-containing waste is fully heated at about 380 ° C and about 3200 psi
Subject to pressure in the supercritical range exceeding (225 kg / cm ² ).
In this range, the gas dissolves very quickly and the normally insoluble organic matter, including grease and oil, dissolves.

Such pressures can be achieved in relatively expensive reaction vessels. An example of such a reaction vessel is Modar, Incorporated, which is a company described in the first one of the above-mentioned two prior arts.
It was proposed by c). Another type of reactor is Zimbro Incorporated (Zimb
There is an autoclave used by a company in Rothschild, Wisconsin, USA known as ro, Inc). Such various reactors are relatively expensive to manufacture. They must maintain an internal pressure of at least 3200 psi (225 kg / cm ² ). Given the overdesign, these are probably 3500psi (2
Designed for 46kg / cm ² ). Because of the use of such target pressures, reactors are generally designed with margins for higher pressures for safety, and therefore they are generally
Has a pressure rating of 5000 psi (352 kg / cm ² ) or higher.

It was inevitable that such a pressure rating would be expensive when introduced into the device. This generally requires the design and manufacture of relatively rigorous reaction vessels. In addition, it is inevitable to make such a pressure tank small. For example, Modder Incorporated's equipment typically allows for throughputs of about 50 gallons (190 liters) per day.
If you try to scale up the model, there will be a problem of gradually decreasing profits. For example, the volume of the pressure vessel can be doubled by only slightly increasing the radius, assuming that the pressure vessel is cylindrical. Nevertheless, this causes limitations due to the practical size of the plant. Plant size is inevitably related to throughput. Furthermore, such plants generally have to continuously supply heat to maintain the temperature required for operation, which is inevitably costly to supply.

The present invention deals with them in a completely different way. The present invention proposes the use of abandoned oil wells. They are generally dug to a sufficient depth that it is possible to obtain a supercritical pressure at the bottom. Even if these are not so deep, they can be used by supplying under pressure. That is, the bottom pressure can be increased by pressurizing the upright water column by pressure boosting on the ground surface. Using the general rule of thumb that pressure increases by about 1 psi (0.07 kg / cm ² ) for every 2 feet (0.61 meters) of water column height, a well at a depth of about 6400 feet (1950 meters) is about It will have a bottom hole pressure of 3200 psi (225 kg / cm ² ). In this case it is not necessary to pressurize the well at the top. In light of this, it can be seen that the well contains a vertical column of water at the bottom or reaction zone where the pressure increases to supercritical pressure. Such an upright water column can be optionally pressurized by adding a pressure head above. There are pressure holding tanks, valves, etc. connected to the well head as a means for adding such a pressure head, but these are generally 3200 psi (225 kg) on the ground.
less expensive than the equipment needed to obtain a pressure of / cm ² ).
The ground facility of the present invention may be one that provides a pressure boost of about 500 psi (35.2 kg / cm ² ). 5400 such equipment
It can assist wells that are only a foot deep (1650 meters).

Here the term pressure vessel will be used somewhat relative in the present invention. The term refers to the bottom of an abandoned well. Such waste wells are preferably sealed to prevent entry into the surrounding formations. Further, the casing is preferably cemented so that the chamber at the bottom of the well can be continuously operated, utilized and operated. This is particularly important to allow industrial waste, which is generally supplied as a continuous stream, to be recycled and processed through the apparatus of the present invention.

Considering the apparatus of the present invention particularly from the standpoint of start-up, the exothermic method is adopted as described below. On the other hand, for the sake of explanation, there is a column of water at ambient temperature in the hole of the well, and the depth of the hole is 8000 feet (2440 meters).
And the well is surrounded by a casing which is cemented and the bottom of the well is plugged at a depth of 8000 feet (2440 meters). This device is specifically set for explaining the operation of starting operation. A bare conductor is disposed in the center of the reaction chamber with a gap in between. This reaction chamber is 7500 feet to 8000 feet (2200 meters to 2440 feet)
It is located at a depth of m. The bare conductor radiates a current radially outward in the chamber. In addition, the conductor has an insulating coating on a portion descending from the ground to reach the reaction chamber. The bare conductor is centrally located within the reaction chamber and is held by standoff posts so that it does not contact the surrounding tubing. The conductors and chambers are very long, for example as long as 100 meters. If the tube has an inside diameter of about 20 cm, the conductors can be appropriately sized and centered along the center of the chamber. This allows current to flow from the conductor to the outside in the radial direction through the material having excellent conductivity surrounding the electrode.

The method of the present invention provides, among other things, a method of heating the surrounding fluid with an electric current. Due to the generation of heat, the surrounding fluid is heated, and as the temperature rises, the current further increases and the temperature further rises. Such an increase in current is due to a decrease in electric resistance. The temperature is finally raised to the supercritical temperature by such an electric resistance heating device. The heat generated by the exothermic oxidation holds the temperature level thereafter. Such oxidation, of course, causes further dissociation of the constituents of the waste. Waste containing bacteria is completely sterilized and bacteria are decomposed.

The present invention takes advantage of equipment such as well holes that are sealed and cemented by a casing.
In deep wells, the temperature of the bottom hole generally increases at a rate of about 1 ° F per 100 feet of depth (ie, 1 ° C every about 54 meters). This increase in temperature minimizes the heating of the temperature of the fluid supplied to the bottom. More importantly, the heat transfer properties of the surrounding formation associated with the sealed and cemented well holes provide heat retention and keep the water in the reaction chamber supercritical. For this reason, water is mixed with the jetted air, and the gas phase fluid has a complete solubility in water and is almost dissolved therein, that is, the waste and gas contained in the water are completely dissolved. To do. In the supercritical state, the surface tension is reduced, so that almost complete mixing is possible, and oxygen and the waste material contained in water come into complete contact. Oxygen can penetrate into even the smallest pores of the particles and can completely oxidize the material, facilitating combustion of the waste.

By-products of waste destruction are carbon dioxide, water and various salts including soluble and insoluble salts. Essentially all living cells are destroyed, so the effluent can be processed even faster. Emissions can be handled more easily as harmful toxins and dangerous toxins are eliminated. The effluent may contain heavy metal salts, which can be removed to produce a cleaner effluent. This is no problem compared to the problems related to the above-mentioned processing.

The above description is a very general description of the method of the invention and the apparatus used for it, and the procedure used is also general.

(Embodiment) Next, an embodiment of the present invention will be described with reference to the accompanying drawings. Shown is a cemented waste well surrounded by a casing, and 10 is a typical casing placed in the well bore. The casing 10 is held in position by a cement outer cover 12, and is in a state of being cemented in the hole of the well. Cement case 10
Is penetrated to a specific depth beyond the above, and such a depth fixes the casing 10 in an appropriate position and prevents invasion of invading objects from various strata penetrated by the casing 10 along the outer surface of the case. It is set to a depth sufficient to do so. The wells have a typical diameter depending on the size of the drill bit used to form them, and at a depth of 8,000 feet (2,440 meters) a suitable downhole pressure as described below. Providing an upright water column that provides (pressure in the borehole). A water column at the bottom with a temperature of 705 ° F (374 ° C) and a height of 8,000 feet (2,440 meters) has a water column of about 350 psi (25
It is necessary to apply pressure of kg / cm ² ). The deeper the well, the less pressure applied to the water column at the surface.

The top of the casing 10 is sealed by a lid member 14.
Various fluid conduits and electrical wiring are threaded through the lid member around which is provided a seal of suitable nature to prevent leakage. Furthermore, the lid member 14 forms a pressure chamber inside the well, which pressure chamber is indicated at 16 at the top of the well. A reaction chamber 20 is provided at the bottom of the well, and the reaction chamber 20 is located above a stopper 22 arranged in the casing 10.
The depth of the well is not explicitly shown, but the deeper the well, the more the plug 22 can be located at the bottom of the casing 10, approximately above the lower end of the hole formed by the casing 10. The extra holes are blocked and isolated. Also,
Stopper 22 is positioned at a height within 100 feet (30 meters) of the bottom of casing 10.

Returning to the description of the upper end of the well, the air source is connected to the pump 24 and is forced through the tubing string 26 into the waste fluid (described below) in the well. The tubing string 26 has an exhaust nozzle 28 extending about 2,000 feet (610 meters). Oxygen in the air becomes bubbles in water, and such oxygen has a water temperature of 233 ° F (111 ° F).
(° C) or higher, the solubility is good, and below this, the solubility becomes poor. The discharge nozzle 28 of the tubing string 26 is concentrically arranged in the tubing 30 for waste fluid,
The tubing string 26 delivers fluid from the pump under pressure as described below. Air exhaust nozzle 28
Through a waste fluid stream.

Appropriate waste is directed into the well through tubing 30 for waste fluid. The tubing 30 extends above the plug 22 and at a distance of 6 inches (15 centimeters) to a position close to the bottom. The bottom is washed away by this gap, all the precipitate is washed away, and flows toward the water surface together with the outflow fluid. Generally, the waste contains the above-exemplified substances, and these are introduced into the well as a dissolved state or slurry. In general, waste fluid is water with waste components ranging from parts per billion to very high concentrations. It can be immediately assumed that the waste fluid is mainly water containing wastes, which contains living cells or organic matter. It is also assumed that the waste fluid is a mixture of different things. Such a mixture is generally characterized as containing HCMSN. This is not a chemical formula, but merely a general element found in the constituents of waste. That is, HC is various kinds of hydrocarbons, M is a metal (sodium is an example of a light metal, and mercury is an example of a heavy metal), S
Indicates sulfur and N indicates other elements. Examples of other elements include various halogens. The waste contains both organic and inorganic components.

Waste is guided through tubing 30, which should extend approximately toward the bottom. This ensures delivery of waste material (HCMSN) to the reaction chamber 20. Generally, the reaction chamber is 100-5
It has a height of 00 feet (30 to 150 meters).

An outlet pipe 32 is connected to the lid member 14, and a regulating valve 34 is provided in the outlet pipe 32. The regulating valve 34 assists the discharge of the processing material. The treatment material preferably flows to the top of the well and is easily discharged.

The regulator valve 34 is for maintaining back pressure, and it is desirable to be able to maintain the pressure at the bottom of the hole above the pressure required for the water to become supercritical. Such pressure is about 3200 psi (225 kg / cm ² ). In fact, various magazines report that such pressure is 218.3 atm. At such pressure levels, and above the critical temperature described below, the density of water, the binding of various molecules including hydrogen, and other physical properties change. That is, water acts as a more polar organic liquid. At this critical point, the solubility of water changes rapidly. At this level, water is a very good solvent for organics. That is, at this temperature and pressure, oil and grease can be mixed with water. Moreover, the density of water is reduced, while the inorganic salts are only slightly soluble. Further, in this state, not only the organic components (especially including oil and grease) can be dissolved in water, but also oxygen can be completely dissolved in water. Overall, at the supercritical point, the gas is taken up in the water and is completely soluble with it. In this state, water has the same density in both the liquid phase and the gas phase. Inorganic salts do not dissolve in supercritical water. These are separated by a stream, picked up and washed away, carried towards the surface of the water and partially dissolved as the water temperature decreases. That is, such salts are usually discharged without collecting at the bottom.

The carbon and hydrogen of hydrocarbon waste is rapidly oxidized.
They therefore form oxides, which include carbon dioxide and also water. These do not cause any problems in processing. Assuming the presence of halogens and metals in the waste, they form salts.
These salts separate and are redissolved as the flow approaches the surface of the water. These are flushed out of the well as described below by the flow of water.

When living cells are contained in water, they are generally killed by the high heat even before entering the chamber 20, and then killed and oxidized by the reaction occurring in the reaction chamber.

Considering the heating in the reaction chamber 20, 38
Is a power source, one of which is grounded to the casing and the other end of which is connected to the conductor 40. The conductor 40 extends to the reaction chamber 20 and is covered with an insulating material so that no current flows from the conductor 40 along its length, but is exposed at the tip 42. The tip 42 is located within the reaction chamber and causes a current flow radially outward toward the casing 10. Therefore, the path of the electric current to the ground side toward the casing is formed by the surrounding liquid. The electric current from the tip 42 is used to initiate the reaction. It is assumed that the temperature at the bottom of the hole in the surrounding ground before the reaction starts is 70-80 ° C. In addition, it is assumed that the well has an upright water column whose height is such that the pressure in the bottom hole exceeds approximately 3200 psi (225 kg / cm ² ), and at this point it is merely an upright water column. Even if the water column contains a lot of different wastes, its analysis is not important for this explanation. It is also assumed that the dielectric constant of water surrounding the tip 42 at this point is 80 or more. However, there will be a sufficient amount of conductive material in the waste to lower the dielectric constant somewhat below 80. A dielectric constant of 80 or less is not important under start-up conditions, but a dielectric constant of 80 is believed to give bad results.
At start-up, the flow is temporarily reduced to heat the water in the reaction chamber.

An electric current first flows from the wire tip 42 and travels radially outwards, and such current produces heat. Recalling that the well is surrounded by a cement jacket 12, which is surrounded by the surrounding formation, some of the heat is conducted away from the metal casing 10. Although dissipated, the heat generated near the tip 42 is almost trapped. When the electric current is passed many times, sufficient heat is collected in the reaction chamber 20 to raise the temperature in the chamber. Moreover, if such an action is generally initiated at an ambient temperature of 70 to 80 °, the temperature is raised until the critical temperature is reached. Inevitably the temperature level approaches the supercritical temperature of 374 ° C. This increase in temperature causes the dielectric constant to decrease more or less linearly. That is, the dielectric constant is generally about 80 at about 25 ° C. Such a dielectric constant gradually drops in water near the supercritical temperature and eventually drops to about 10 or less. Such a drop reduces the required current and promotes the volume of heat in the reaction chamber 20. The reaction chamber 20 quickly becomes supercritical, thereby fluidizing waste molecules at sites within the chamber 20, that is, exposing these molecules to supercritical water and oxidation. This kind of startup can be done with water that is almost pure water,
Generating more heat speeds up the process if the water contains combustible waste.

The pump 24 is switched at the beginning of operation. Some oxidation takes place even before the supercritical condition is reached. Pressurized air is pumped through the conduit and expelled from tip 28. The air does not merely bubble into the tip 28. As the supercritical condition is approached, the solubility of oxygen in water increases rapidly, and the size of bubbles decreases with the dissolution of air.
Oxygen easily dissolves in water, allowing the oxidation of waste molecules including HCMSN. At this point oxygen is being led into the water. Water containing waste flows to the bottom of the well and is accompanied by oxygen. Considering the condition where water is trapped and cannot enter the stream, it becomes clearer that the supercriticality of water in this condition is represented by the water as a supercritical fluid that is not exactly a liquid. In this state, the density of the water in the chamber 20 changes, but it remains in the state of a straight water column. In the supercritical state such density is the critical density of water 0.32
It will eventually exceed 5g / cm3. A continuous stream of air (or oxygen if a more expensive approach is desired) is poured into the continuous stream of waste containing water. Water is then drained from the top through relief valve 34. This relief valve
34 is adjusted to maintain an adequate system back pressure to ensure that the supercritical pressure is maintained in the chamber while maintaining inflow and outflow.

Such pressures should be considered to be pressures above 3200 psi (225 kg / cm ² ). This pressure can be obtained by utilizing a well whose depth is subject to such pressure. If the well is not deep enough, the back pressure valve 34 will keep the pressure head of the well well. If the wells are shallow, the back pressure of the system is reduced to 3200 psi (225 psi) in reaction chamber 20.
must be kept above kg / cm ² ). Also, when the well is deep, back pressure can be reduced to virtually zero.

Desirably, the waste stream contains substantially sufficient oxidizable organic material. Here, the term oxidizable does not necessarily refer to one that is combustible with oxygen in the air, but rather to a material that is oxidizable within the chamber 20 but which is converted by the action of water. Chamber 20
Once oxidation of the waste introduced therein begins, such oxidation continues. Therefore, the power supply can be switched to reduce the required current. Also, the electric heating time can be shortened. Such operation is self-maintaining in a sense. That is, sufficient heat is generated by the combustion of HCMSN in the vicinity of the chamber 20, and the chamber 20 is maintained at the supercritical temperature. Such maintenance temperatures are generally desired to be 374 ° C to about 400 ° C. Although energy above this temperature level is useless, it is desirable to regulate the current to control it at a constant temperature to avoid adverse effects even after the start of combustion of the waste material.

As mentioned above, such a process is self-sustaining and ideally self-sustaining by the continuous introduction of a sufficient amount of combustible organic waste. The exact amount required is generally relatively small, no more than a few percent of the total system throughput. That is, if the feed waste contains about 0.02% to 5% of waste material, then the waste input is sufficient to continue combustion. The determinants are flow rate and concentration. Considering the heat loss of the well, 200pp at a flow rate of 500 gallons / minute (1900 liters / minute)
Operation can be maintained as long as it contains m combustible hydrocarbons.

If such conditions are met, the operation of the system does not require any more energy input to maintain at least the supercritical condition. Only power input to the pump is needed. Since the waste is generally sent in the form of an aqueous lysate and air is also required, the only energy consuming mechanism required to maintain operation is two pumps.

Some of the heat generated in chamber 20 is absorbed by the surrounding ground. The wells can be well insulated so that the purified waste fluid that is discharged is actually sufficiently clean and that it is hot enough to recover some energy from it for pump and other equipment operation. it can. That is,
Self-sustaining properties can be maintained almost completely as long as the waste is fed to the converter.

In practice, the tubing and casing are protected by a small current. Oxygen and especially carbon dioxide dissolved in water affect metal pipes as the temperature and pressure in the well rises. Corrosion resistant stainless steel is expensive and soft steel is available when protected by the cathode electrode system. This depends on the conditions, but it is desirable that the bottom of the pipe or tubing be protected in such a manner.

Countercurrent heat exchange is performed by the downward flow of the feed water and the upward discharge of the hot water. Such countercurrent makes it possible to maintain adiabatic equilibrium. The discharged hot water delivers up to 1 million BTU (1 BTU = 0.252 kcal) of heat energy per unit time. Such heat can be used by the feed water preheating device without being discarded to heat the feed water. In fact, depending on the combustible fuel in the water, the heat released from the well exceeds the energy needed to operate the well, that is to say the energy used primarily for pump power. This can be changed by changing the fuel supply amount.

Safety is increased by placing the high pressure reaction chamber underground, which replaces the high pressure high temperature equipment located on the ground. In addition, safety is secured by isolating the high-pressure area underground. Such a configuration also contributes to cost reduction.

Wells usually form an isolated chamber, which minimizes the loss of water to or from the well. Also, by surrounding the pipe with cement, heat can be controlled and heat loss can be limited. In addition, the chamber at the bottom of the well is surrounded by a layer below the ground at high temperatures, which reduces the temperature difference and reduces heat loss.

As mentioned above, the general effect is that heat is gradually supplied to start raising the temperature to the supercritical condition. Once this is reached and the operating cycle begins, the running water discharged from the well is substantially purified. That is, the waste mixture injected into the well is substantially converted. The effluent contains carbon dioxide as a result of the combustion of various hydrocarbons. The runoff also contains salt. The purified water is discharged through the relief valve 34, thus making the purification easy. Purified water mainly contains common metal salts such as salts of mercury and sodium. This will, of course, depend on the practical composition of the waste that is introduced to the well.

The above description relates to the preferred embodiment of the present invention,
The scope of the invention is limited only by the claims.

[Brief description of drawings]

FIG. 1 is a sectional view of an apparatus for wet-oxidizing organic waste in wastewater showing an embodiment of the present invention. 10 …… Well casing (metal) 12 …… Well jacket (cement) 14 …… Lid member 20 …… Reaction chamber 22 …… Plug 24 …… Air pump 26 …… Air inlet tubing 30 …… Waste water inlet tubing 38 …… DC power supply 40 …… Coated conductor 42 …… Tip conductor part

Claims (10)

[Claims] 1. A method for wet-oxidizing organic waste in wastewater, comprising: (a) flowing wastewater containing organic waste into a deep well with heat insulation; Continuously injecting oxygen into the well, (c) guiding the wastewater into the well to a depth where the pressure at the bottom of the well increases to the pressure required to bring water into a supercritical state, and (d) at the bottom of the well. An electric current is applied to the wastewater through a control mechanism on the ground to generate an appropriate amount of resistance heat in the wastewater to initially heat the wastewater at the bottom of the well to cause oxidation of the wastewater in the wastewater, and (e) continuously. Oxidize the organic waste in the inflowing wastewater to continue the generation of heat in the well to maintain the temperature required for supercritical water, and after the heat generation is maintained by the oxidation of the organic waste. Ending the initial heating via the control mechanism, and (f) the presence of wastewater in the well. In order to continue the wet oxidation of waste, the wastewater to be treated is continuously flowed into the bottom of the well, and oxygen is injected into the inflowing wastewater over the treatment period. A method for wet-oxidizing organic waste in wastewater, which comprises treating the wastewater while maintaining the temperature and discharging the treated wastewater together with oxidation products from a well. 2. The wastewater to be treated is blown to the bottom of the well through wastewater inflow tubing at the center of the well, the water flow is reversed at the bottom of the casing at the peripheral surface of the well, and the insoluble sediment is washed away from the bottom, and inside the peripheral casing. The method for wet oxidizing organic waste in wastewater according to claim 1, wherein the water is raised with the treated wastewater and discharged from the top of the well. 3. The wastewater according to claim 2, wherein an electric current is made to flow through the wastewater toward the metal tubing in the well in the lower part of the wastewater inflow tubing to perform cathode protection for the metal tubing. For the wet oxidation of organic wastes therein. 4. In order to pressurize the oxygen, compressed air is caused to flow to a predetermined depth through a tubing string provided at the center of the well, and air is bubbled in the waste water so that a flow accompanied by the air is considerably generated in the well. The method for wet-oxidizing organic waste in wastewater according to claim 2, wherein oxygen in the air is dissolved to a depth and dissolved with a decrease in the surface tension of the wastewater to further oxidize the organic waste. 5. The compressed air is preheated at least through the metal tubing by the treated high temperature wastewater flowing upward from the bottom of the insulated well in the casing of the peripheral surface and then flows downward. A method for the wet oxidation of organic waste in wastewater according to claim 4, which is released into untreated wastewater. 6. A stopper mechanism for limiting the bottom to a predetermined depth determined by the depth of the well is provided at the bottom of the well, and a casing on the peripheral surface of the well provides a predetermined stopper mechanism at this stopper mechanism. An upright water column having a pressure of 1 is formed and held, and a supplementary pressure is applied to the waste water flowing in at a site on the ground so that a supercritical pressure is obtained in the upright water column at the site of the plug mechanism. A method for the wet oxidation of organic wastes in wastewater according to claim 1. 7. The method according to claim 1, wherein the top of the well is closed by a cover member, and the tubing for inflowing and discharging the waste water is retained through the cover member to maintain the pressure in the well. Method for wet oxidation of organic waste in wastewater. 8. In order to change the water pressure at the bottom of the well,
7. A method for wet oxidizing organic waste in wastewater according to claim 6, wherein the wastewater inflow pressure is adjusted. 9. In the aboveground part of the well, one pole of a DC power source is connected to the ground through tubing, and the other pole is connected through a lead wire to a conductor portion at the tip provided in the bottom of the wastewater inflow tubing. The discharge water is discharged, and the current from the electrode tip portion is passed through the waste water in the reaction chamber to heat the waste water, and then the current is weakened to cause the cathode protection current to flow in the chamber. A method for wet-oxidizing an organic waste in the wastewater according to the item. 10. The wastewater according to claim 9, wherein a conductive wire connecting the DC power source and the conductor portion at the tip is insulation-coated to limit the discharge inside the well to the reaction chamber at the bottom of the well. For the wet oxidation of organic wastes therein.