GB2291055A - Process for the treatment of waste or chemically contaminated soil - Google Patents

Abstract

A process for reducing the odorous effect of substances found at a waste-site is provided in which the media containing the odorous substance is partially oxidized, e.g. contacted with KMnO4, so that the substance is rendered substantially nonodorous without significant evolution of heat or odorous gases. <IMAGE>

Description

PROCESS FOR THE TREATMENT OF WASTE OR CHEMICALLY CONTAMINATED SOIL This invention relates to the treatment of chemical contaminants in soil or other solid media.

There are numerous unwanted effects that accompany the presence of chemical contaminants. Toxicity, irritation, plant damage and other effects can often be determined with good quantitative precision as a function of the concentration of the substance doing the damage. The offensiveness of odours created by such substances is, however, necessarily a subjective evaluation.

It is generally true that, for a given odorous substance, the greater the amount of that substance that is present to contact the receptors, the worse the problem will be.

It appears that one's tolerance for the odour of a given substance is related both to the type and concentration of that substance in air.

A number of means have been created to objectify the subjective sense. One of the most objective measurements of odorous character is the odour intensity threshold. The odour intensity threshold is a physical property of a particular composition as a function of its concentration. As used throughout this specification, the odour intensity threshold is the lowest concentration of a substance in air that can consistently be distinguished from pure air. Various federal, state, and local regulations limit nuisances including odours. This can be expressed as a function of the odour intensity thresholds. These thresholds are often several orders of magnitude lower than threshold concentrations set for other phenomena such as toxicity.

It is highly desirable to eliminate the effects of harmful or offensive substances that have low intensity thresholds. Since this is a function of the concentration of the malodorous substance, this is most readily done by eliminating the presence of the substance itself. The prior art has included many techniques for achieving this end.

US-A-5,207,532 discloses the use of hydrogen peroxide and chlorine dioxide as an oxidant for soil remediation. This has been somewhat motivated by the stimulation of heat and gas generation of such in-situ application. This heating and vaporizing effect improves the stripping of volatile chemicals from the soil. That is, the heat generated by the oxidation process volatilizes the contaminants and removes and disperses them through the atmosphere.

Depending upon the contaminants present, this can also pose grave difficulties. This is particularly true when the contaminate is mixed with other malodorous substances. That is, both hydrogen peroxide and sodium hypochlorite can evolve gases (oxygen or chlorine respectively). When used to oxidize contaminants they increase the vaporization rate of odorous chemicals irrespective of whether they are the target contaminants. This may actually worsen the problem by volatilizing nontargeted contaminants that otherwise would not have posed an odour problem. Moreover, the concomitant generation of heat can also present safety hazards such as increasing the risk of fire.

Thiophenes and thiophene derivatives are compounds that have extraordinarily low odour intensity thresholds. They are volatile and are soluble in water. Many of the compounds of this class have odour intensity thresholds on the order of magnitude of parts per billion (ppb). This is particularly true of tetrahydrothiophene which is a stable compound. Unfortunately, these compounds are often found in carbonaceous deposits.

Areas contaminated with petroleum products can have complex deposits that include thiophenes and thiophene derivatives. Some such sites have soils contaminated in various layers mixed with substances such as sulphur dioxide (in solution), any number of volatile organics, tars, drilling fluid remnants, and thiophenes.

Remediating the soil at such sites is a complex problem. One could use hydrogen peroxide to oxidize some of the volatile organics but the heat generated in the process would evolve gaseous thiophenes that would be found extraordinarily offensive by almost anyone in reasonable proximity to the site. One solution to this problem might be the addition of a vapour phase removal method for the thiophenes so evolved. Such operations are expensive and still do not assure that thiophenes will not be released into the atmosphere. Another solution to this problem might be found in solidifying all or some of the layers of soil containing the contaminants. This could be done through the application of a blast furnace slag based cement such as that disclosed in US-A-5,058,679.

Still, it is possible that not all layers would uniformly solidify leaving a multilayer/multiphase mixture that still contained obnoxious thiophenes.

Thus, there remains a need for a process which can render thiophenes and thiophene derivatives substantially nonodorous.

There is also a need for a process which can be used in concert with a variety of remediation schemes to reduce the ill effects of thiophene and thiophene derivatives.

In accordance with this invention a process for reducing the odour of substances that ordinarily act as odorants is provided in which the media containing the odorous substance is partially oxidized. In one aspect of this invention, this occurs through contacted with a solution comprising KMnO4. The partial oxidation occurs without significant evolution of heat or volatilization of odorous gases. KMnO4 may be introduced either in situ with the media containing the contaminate or it may be done ex situ. In a most preferred embodiment of this invention, tetrahydrothiophene in soil is partially oxidized in situ through the introduction of a KMnO4 solution run through the centerline of an auger. In this way, tetrahydrothiophene or thiophene derivatives found at waste sites can be partially oxidized to the more tolerable sulfalone and sulfalone derivatives.

Fig. 1 is a cutaway side view of an apparatus used to practice an embodiment of the invention.

Fig. 2 is a cutaway side view of an area in which an embodiment of the invention was practiced after removal of the apparatus shown in Fig. 1.

It has been found that soil or waste sites containing odorous compounds, particularly thiophenes and thiophene derivatives, can be successfully treated to render them nonodorous by treatment with KMnO4. Odorous as used throughout this specification refers to the property of a substance which stimulates the sense of smell and is present in concentrations above the odour intensity threshold of that substance. A substance is rendered nonodorous according to this specification when: a) it is present in concentrations below its odour intensity threshold, or b) when it has been converted into another substance which is then present in concentrations below the odour intensity threshold for that substance, or c) it is converted to a substance with a less noxious odour.

In the method of the present invention, chemically contaminated soil or waste is mixed together with an oxidizing agent which only partially oxidizes the contaminant. In a most preferred embodiment the oxidizing agent is a KMnO4 solution. It is preferred that this be accomplished by injecting the KMnO4 solution into the contaminated soil in situ. This oxidizes the contaminants leaving the predominate reaction products of manganese dioxide and the oxidized chemical products.

In a most preferred embodiment of the invention, a solution of potassium permanganate is injected into highly odorous tetrahydrothiophene present in buried soils, tarry wastes, drilling muds, and asphaltic wastes. This may be done in any manner in which physical contact between the substances is attained. However, the use of a vertical mixing auger is most preferred. An auger with a diameter of 2 feet has been found to be most useful in this regard although this is not a critical aspect of this invention. This preferred auger has a shroud or enclosure around it which is routed to a vapour control system. In this way, use of the auger will not cause undue release of any noxious substances from beneath the surface. When this method is employed, KMnO4 is first mixed in a hopper with water. The solution of KMnO4 in water is injected through the centerline of the auger. It should be noted here that the auger, in such applications, is used primarily for mixing the soil and the oxidant. Dry KbInO4 should not generally be used in applications with hydrocarbon contaminated soil since it may create a fire hazard.

Fig. 1 illustrates an auger apparatus that has been found useful in such applications. The auger shaft, 1 is a hollowed sturdy cylinder which houses the auger, 2. The auger, 2 has a plurality of auger teeth, 2a which bore through the earth, 10 and its deposits via a rotary motion. Rotary motion is applied by an engine or motor apparatus (not shown) as commonly found in auger applications.

The auger shaft has no helical flutes that raise the disturbed soil. As such, the apparatus mixes the soil without removing it.

The area, 11 shown in Fig. 1 is the area through which the auger bores. This area, 11 contains the odorant or is situated in such proximity to the odorant so that injected reagent contacts the odorant. In a most preferred embodiment, the area, 11 contains the odorant to be treated.

The auger, 2 has a hollow centerline through which runs the reagent tube, 3. Reagent, such as KMnO4 is pumped into the reagent tube, 3 by means of a pump fed hose or other suitable reagent transport means (not shown). This reagent tube, 3 terminates at the end of the auger near the auger teeth, 2a or along the auger blade, and is coterminous with the reagent injection ports, 4. The auger also has one or more shaft reagent injection ports, 6. Reagent is deposited in situ through these reagent injection ports (4 and/or 6). One or more of such ports are useful, provided a sufficient amount of reagent (as set forth below) can be deposited in the area containing the odorant. If a large quantity of reagent is needed a large number of reagent injection ports will generally be desirable.

Oxidant reagent, such as KMnO4, solidification grout, or other agents can all be delivered through the auger shaft. They can be premixed and added at the same time, sequentially added, or multiple delivery tubes can be used to feed any number of such agents through the shaft in any order.

In the application of the auger device shown in Fig. 1, at least one shroud, 7 surrounds the auger. Shroud, 7 is a casing made of, steel, aluminum, high density polyethylene, or other material capable of holding a vacuum and containing gases and other fluids.

The shroud, 7 is sealed against the auger shaft by means of a seal, 7a that allows the shaft to rotate and translate. The shroud is also sealed against the ground, 10 by means of a knife-edge insertion into the ground or by a flexible skirt held to the ground by sandbags or other weighted objects. Alternatively, the shroud may be provided with a jointed seal around its circumference so that it may be broken down into two pieces.

A vacuum can be applied to the area under the shroud, 7 by any of the well known methods gas evacuation methods such as the use of a valve (not shown) connected to a pump assembly (not shown). When a vacuum is applied to the area contained by the shroud, 7 evolving gases or gases released from deposits of volatile materials can be evacuated to a treatment system. Well known scrubbers and other treatment systems are suitable for this purpose.

When the boring/reagent addition is complete, the auger and auger shaft are withdrawn for the shroud through a sealable hole in the top of the shroud, 7. Backfill and/or a cementitious substance are injected into the area, 11 bored by the auger through the hole in the top of the shroud or through the reagent injection ports, 2a and 6 prior to the complete removal of the auger. It is preferred that cement be simply poured through the reagent tube, 3 and out the reagent injection ports, 2a and 6 just prior to the point in which the auger teeth break the surface of the earth, 10 during the removal of the auger.

Fig. 2 shows the bored site upon complete removal of the auger and the upper half of the shroud. Cover plate, 8 is sealed against the lower half of the shroud, 7c. This cover plate, 8 thus acts as a cap while the treated area sets and settles. This generally takes about 24-48 hours but is dependent upon the cement used, additives thereto, and atmospheric conditions at the site. The cover plate can be constructed from any sturdy material having diameter or perimeter at least a little larger than the area bored. A transient air treatment system can be affixed to the sealed container if needed to further control the emissions of the treated soil if necessary. The sealed container can further remain in place or can be later removed. Typically, the site is cemented and the container, 8 is removed after several days.

The parameters used to define an effective amount of KMnO4 addition include the solution concentration, pumping rate and the auger mixing rate. These parameters may be combined to define an effective dose of potassium permanganate in terms of the amount of KMnO4 per amount of soil sufficient to oxidize tetrahydrothiophene present to sulfalone. Preferred doses are between about 4/5 and 4/3 mole of KMnO4 per mole of tetrahydrothiophene in soil. An excess of KMnO4 may be necessary if other easily oxidized material (such as organic carbon compounds) are present in the soil.

In a most preferred embodiment of this invention, about 41 grams of KMnO4/litre of water (.26 moles/litre) are mixed prior to delivery. This can be adjusted up to the solubility limit which is about 63.8 grams per litre at 20 OC (.40 moles/litre). Once prepared, this solution is delivered into the soil at a rate of between about 1 to 10 gallons (of solution) per minute. This rate ensures that the soil is being treated with 1.5 to 15 moles of KMnO4 per minute. Using a 2 ft. diameter auger at a penetration rate between about .66 ft./minute and .9 ft/min, this embodiment of the invention will treat between about 485 mg/kg of tetrahydrothiophene and 11,000 mg/kg of tetrahydrothiophene.

Because of the auger/shroud/emission control system, variable soil characteristics and the complex thermodynamics of the soil/water/tarry waste system, it is desirable to use a qualitative relation between soil concentrations and ambient vapour concentrations (where the threshold level applies) to make adjustments to the system. That is, vapour emissions within the shroud can be monitored in real time and the auger rate can thereby be adjusted accordingly to fine tune the system and minimize emissions.

It should be noted that for volatile components like tetrahydrothiophene and sulfalone, emissions can be considered proportional to the soil concentration and the rate of soil disturbance (augering rate). This means that the relative emissions rates are proportional to the respective concentrations of the substances in the soil. The volatility of the material is another parameter to consider. Tetrahydrothiophene has a melting point of -141 OF, a boiling point of 250 "F, and a vapour pressure of .448 psig at 85 OF. Sulfalone has a melting point of 81 "F, a boiling point of 549 "F, and a vapour pressure of .000124 psig at 85 OF.

Thus, it can be seen that the tetrahydrothiophene conversion to sulfalone in situ limits emissions considerably.

Other techniques can also be used for contacting the KMnO4 with the contaminants in situ. It is desirable that the technique selected does not contribute to the volatility of the odorous substance. Thus, while one could successfully mix KMnO4 through the use of backhoes and other machinery, it is not the preferred method when treating tetrahydrothiophene because such mechanical stimulation could increase the volatility of the odorous agents.

Injection of KMnO4 may be done either before, after, or in addition to other additives including other oxidants (such as hydrogen peroxide and aqueous sodium hypochlorite), neutralization agents (such as lime and flyash), and solidification agents (such as cements). If any such additional agents are used one must be careful to avoid the generation of heat and vapour. The use of KMnO4 will destroy most of the tetrahydrothiophene in-place and reduce the load on the vapour emission control system which encloses the above-ground auger machinery. The oxidant will also reduce the potential impact of odours on the surrounding community. In most instances, 95E of the tetrahydrothiophene will be rendered nonodorous by conversion to a sulfalone within a matter of minutes.

There is little or no generation of heat in this process. Hence, other potentially odorous substances are not volatilized and there is no substantial fire hazard.

Without being bound to theory, it is believed that the process involves the following transition for tetrahydrothiophene:

Again without being bound to theory, oxygen is believed to be generated for use in this reaction according to one or both of the following reactions: At a pH less than 2, 5 C4H8S + 12 H+ + 4 KMnO4 -s 5 C4H802S + 4K4+ + 4Mn2+ + 6 H20 at a pH greater than 4, 3 C4H8S + 4 H+ + 4 KMnO4 -u 3 C4H802S + 4K+ + 4 MnO2 + 2H20 At pHs greater than two but less than four, there is probably a mix of the two equations occurring.

Again, without being bound to theory, it can be said that the thiophene ring is ordinarily easily ruptured by strong oxidizing agents. Such an event would certainly be accompanied by the evolution of heat and gases. In the process of the instant invention, however, the thiophene ring is not ruptured. Rather, the thiophene derivative is converted to a partially oxidized, yet stable, sulfolane derivative which is substantially nonodorous.

The methods of practising this invention have numerous advantages of prior art methods for addressing these problems.

The methods of this invention can also be practiced in concert with well known remediation techniques. One skilled in the art will readily appreciate that methods such as "pump and treat" excavation technologies, vacuum extraction methods with or without air sparging, air stripping, bioremediation, and other technologies need not be practiced separate and apart from the methods herein disclosed and claimed.

For example, one may wish to apply a "pump and treat" method to a complex waste site containing an array of contaminants including tetrahydrothiophene. Under ordinary circumstances, excavation of the contaminants would tend to liberate the highly obnoxious tetrahydrothiophenes. A solution to this problem would be to first apply the method of the instant invention thereby rendering the waste substantially nonodorous with respect to the tetrahydrothiophene.

EXAMPLES In each of the Examples that follow, GC refers to Gas Chromatography conducted with a Hewlett Packard 5880 Gas Chromatograph containing a PONA column (Cross linked Silicone Gum having) a 50m X .2mm X .5 micrometer film thickness. Either a Flame Ionization Detector (FID) or a Sievers 350B detector was employed in concert with the GC (as noted). Deionized water was obtained from a Barnstead/Thermolyne water filtration unit using D0803 and D8902 cartridges. THT (Tetrahydrothiopene) was obtained from Aldrich Chemical Company of Milwaukee, Wisconsin. Ether refers to High Purity Solvent Ether which is a 99 solution of dimethyl ether obtained from Baxter Healthcare Corp. of McGraw Park, I1. ESI dirt is a mixture obtained from Environmental Solutions, Inc. of Irvine, California.The ESI dirt contains 990 g of wet soil, 300 g of tar, and 30g of 96wit sulfuric acid.

EXAMPLE 1 The following were added to an 8 dram vial: .03 cc tetrahydrothiophene, 10.09 g of filtered deionized water, and 1 cc ether.

A magnetic stirring bar was added to the vial containing the reactants and reagents and the vial was then sealed with a natural rubber septum. The vial was then set on a IKAMAG RCT stir plate, and stirred.

After a few minutes, a 4 microliter sample was removed from the vial and injected into the GC with an FID. The oven of the GC was initially set at 40 OC and was raised to 300 OC over the course of 26 minutes (lOC/min). This first sample gave an initial THT level in the sample relative to the ether. This sample is referred to as I in the chart below. The retention time of the ether was approximately 6 minutes while that of the THT was approximately 14.5 minutes.

2.2. cc of .32M potassium permanganate solution (KMnO4 was obtained from Aldrich Chemical Company) in deionized water was then added to the sample. One minute after the addition, a 4 microliter liquid sample was removed from the vial and injected on the GC with the FID. The results for this sample are shown under A in the chart below. This sample was also evaluated 2.5 weeks later with the GC outfitted with a Sievers detector. Results for this sample appear under B in the chart below.The results of these tests are presented in Table I: TABLE I

Sample GO Count of THT in Solution (ppm) I 3000 (FID) A 20 (FID) B - 30* (Sievers) *95E of the sulphur contained in the solution (by weight percent) was found to be present as sulfolane.

This example illustrates that the oxidation of THT by KMnO4 reduces the presence of thiophenes by several orders of magnitude. Further, it illustrates that this technique has a lasting effect. Sulphur that was detected in samples weeks after treatment was found to be present primarily in the form of sulfalone which is much more tolerable than is THT.

EXAMPLE 2 The same procedure was used to prepare a THT sample as is described in Example 1. Again, the initial sample displayed a retention time of 6 minutes for the ether and 14.5 minutes for the THT (Sample I).

.lg of a 30wE Hydrogen Peroxide solution was then injected into the vial with stirring. One minute after the hydrogen peroxide addition, a 4 microliter liquid sample was removed from the vial and injected into the GC (Sample A). Further samples were taken and analyzed at 25 minutes after injection of hydrogen peroxide (Sample B) and 45 minutes after injection of hydrogen peroxide (Sample C).

The results of GC (with FID) analysis appear in Table II. TABLE II

Sample Concentration THT in Solution (ppm) I 3000 A 1280 B not detectable C not detectable This example shows that hydrogen peroxide also effectively oxidizes THT. This, of course, is an expected result. Along with this oxidation comes the generation of heat which can volatilize any remaining thiophenes and other pollutants thereby exacerbating rather than abating the problem solved by the process of the instant invention.

EXAMPLE 3 20.32 grams of ESI dirt with THT (6g THT/1260g ESI dirt) was added to a 2 ounce small neck bottle. The bottle was then sealed with a septum. After setting sealed for one hour, the bottle was placed in a 78 OC water bath. The bath was then brought to and kept at a boil. A gas sample was removed and injected on a GC with Sievers detector 1.75 hours later. The Sievers Detector has a selective linear response to sulphur compounds and does not respond to the hydrocarbons in the tar. The GC was held at 100 C for 3 minutes and was then ramped at 100/mien. A second sample was injected into the GC with Sievers Detector 6 minutes later. The average of the readings for these two samples was taken as the initial THT level and is designated Sample I in Table III below.

A 50 cc empty syringe was inserted into the septum of the vial.

Thereafter, 1.1 cc of a 30wt solution of hydrogen peroxide solution was injected into the vial. Gas evolved and pushed out the plunger in the empty syringe. One minute later, a 1 cc gas cap sample was taken (Sample A) and injected into the GC with Sievers detector. At this point 50+cc of gas had been trapped in the gas collection syringe. The gas collection syringe was removed 3 minutes after it was inserted into the septum but the needle was left inserted in the septum so that gas cap samples could be taken. A gas cap sample was taken at 17 minutes after insertion of the syringe (Sample B); then 2.1 cc of a .32 M KMnO4 solution was added to the vial. A gas cap sample was withdrawn (Sample C) and placed on the GC with Sievers Detector after the KMnO4 solution has been present in the vial for more than 1 minute.Another sample was analyzed 32 minutes after the introduction of the KMnO4 (Sample D) and 90 minutes after the introduction of KMnO4, another sample (Sample E) was taken and analyzed on the GC. The vial was then allowed to cool to room temperature. After 13 days a sample was taken and analyzed on the GC (Sample F).

All samples of Example 3 were analyzed using GC with Sievers Detector, as were the samples in all of the following examples.

TABLE III

Sample THT Concentration in Vapour Headspace of Vial (ppm) I 10,600 A 1800 B 1000 C 810 D 640 E 230 F 26 This example highlights the differences between oxidation with hydrogen peroxide and oxidation with KMnO4. Use of hydrogen peroxide generated heat and gases with whereas KMnO4 did not.

Further, the efficacy of KMnO4 was significantly better than that of the H2O2.

EXAMPLE 4: DRILLING MUD MIX-NaOCl A solution was prepared by mixing 50 cc of a conventional water base drilling mud with 100 cc of a conventional oil base drilling mud. THT was added until the ratio of THT to drilling mud mixture was .48g/100g. 20.16g of this THT and drilling mud mixture was then place in a 2 oz. small neck bottle. The bottle was sealed with a rubber septum and placed in a boiling water bath.

After 1 hour, a sample was withdrawn from the bottle and analyzed in the GC with Sievers Detector. This established the initial THT level (Sample I in Table IV below).

Next, a 50 cc syringe equipped with a needle was inserted into the septum to monitor gas evolution. Following this insertion, 5 cc of NaOCl (Sold as CLOROX brand bleach, under a trademark of the Clorox Company) was injected into the bottle. After 1 minute, a 1 cc gas cap sample was taken with a pressure lock syringe. This sample was then injected on the GC with Sievers Detector for THT analysis (Sample A in Table V below).

Samples were then periodically withdrawn from the bottle 15 minutes after NaOCl introduction (Sample B) and 90 minutes after NaOCl introduction (Sample C).

After Sample C was withdrawn, another 5 cc of NaOCl solution were added to the bottle. Gas cap samples were then taken 1 minute after the additional NaOCl introduction (Sample D), 14 minutes after the additional NaOCl introduction (Sample E), 11 hours after the additional NaOC1 introduction (Sample F), and 8 days after the additional NaOCl introduction (Sample G). Sample G was taken at room temperature (approximately, 20-25 "C). After Sample F was taken, the water bath was turned off for approximately 8-12 hours.

The GC readings indicated the following THT concentrations: TABLE IV

Sample THT Concentration in Vapour Headspace of Vial (ppm) I 8600 A 3400 B 2500 C 2300 D 960 E 240 F 100 G 12 This example illustrates that NaOC1 is also an effective oxidizing agent. However, as with the case of H202, elevated temperatures and evolution of gases exacerbate, rather than minimize, the pollutant control problem.

EXAMPLE 5: THE ADDITION OF LIME AND KMnO4 TO DIRT, TAR, AND ACID A tedlar bag was fitted with a septum and a gas valve. 20.23 g of ESI dirt with THT (6g THT/1260g ESI dirt) was then added to the bag which was thereafter heatsealed. The tedlar bag was then evacuated and 100 cc of room air was injected into it. A sample (Sample I in Table V below) was withdrawn from the bag and placed on the GC with Sievers Detector to obtain an initial THT reading.

After taking the initial sample, 2.4 cc of a lime suspension of 4 g of CaOH in 16 cc of water was injected into the bag. The contents of the bag were then kneaded and mixed together. A sample was withdrawn from the bag for THT analysis (Sample A). 20 Minutes later, another sample was withdrawn from the bag for analysis (Sample B). Following this, 2 cc of additional lime suspension were then injected into the bag followed by 3.4 cc of a .32M KMnO4 solution. Gas samples were then withdrawn from the bag for analysis 1 minute after the second addition of lime (Sample C), 15 minutes after the second addition of lime (Sample D), 180 minutes after the second addition of lime (Sample E), 3 days after the second addition of lime (Sample F), 7.75 days after the second addition of lime (Sample G), and 19 days after the second addition of lime (Sample H).

TABLE V

Sample THT Concentration in Vapour Space of Bag (ppm) I 125 A 158 B 109 C O D 0 E 0 F O G 0 H 2 This example illustrates the efficacy of the KMnO4 process herein claimed. The level of THT remained essentially zero on aging for up to 19 days (at room temperature). The addition of lime to the KMnO4 provided a slight improvement over the use of KMnO4 by itself.

EXAMPLE 6: HOT ESI DIRT WITH H22 The procedure outlined in Example 5 was repeated except that the dirt was first heated to 100 OC in a water bath (actual dirt temperature was about 95 C). THT in the vial headspace was analyzed and is presented in Table VI below as sample I. About 9 m/m of H2O2 was introduced into the vial.

Within one minute of the introduction of H2O2 vigorous gas evolution was noted. At this point, a sample was taken and analyzed (sample A).

The vial was then overpressured causing the sample cap to pop off of the sample vial. Gas continued to evolve. A septum was placed over the vial and a vent needle was inserted. 1.5 cc of water was added to the sample 5 minutes after the H2O2 was added to it. An additional 1 cc of water was added to the sample 20 minutes after the initial introduction of H2O2. Samples continued to be drawn and analyzed 10 minutes after the initial introduction of H2O2, 25 minutes after the initial introduction, and 45 minutes after the initial introduction.

High heat and gas evolution characterized this run particularly in light of the fact that the soil started out at elevated temperature (simulating actual conditions during remediation at some waste sites) and that the H202 was present in high concentrations.

TABLE VI

Sample THT Concentration (ppm) I 6500 A 900 B 120 C 250 D 400 This example demonstrates the risks involved in using H2O2 as an oxidizing agent where the soil may already be under somewhat elevated temperatures. Further heat generation and gas evolution accompany this process. Moreover, the reduction in THT is not as pronounced as with the application of KMnO4.

Claims (8)

1. A process for reducing the odorous effect of substances found at a waste site comprising: partially oxidizing the odorous substance in situ without the substantial generation of heat.

2. The process of claim 1 wherein the odorous substance is present in quantities above their odour intensity thresholds before partial oxidation and said odorous substances and their partially oxidized derivatives are present in quantities below their odour intensity thresholds after the application of said process.

3. The process of claim 2 further comprising the step of adding a solidification agent to said odorous substance and thereby solidifying said odorous agent, said partially oxidized odorous agents, and other contaminants.

4. The process of claim 2 further comprising the step of adding a neutralization agent.

5. A process for reducing the odorous effect of substances found at a waste site comprising: contacting the media containing the odorous substance with KMnO4 so that said substance is rendered substantially nonodorous without significant evolution of heat or odorous gases.

6. The process of claim 5 wherein the odorous substance is present in quantities above their odour intensity thresholds before partial oxidation and said odorous substances and their partially oxidized derivatives are present in quantities below their odour intensity thresholds after the application of said process.

7. The process of any one of claims 1-6 wherein said tetrahydrothiophene is present in said media in concentrations between about .1 and 10000 grams per bank cubic yard.

8. The process of any one of claims 1-7 conducted at atmospheric temperatures between about 10 "C and 30 OC.