Details for Patent: 5,753,494

Title:	Method and apparatus for treating contaminated soils with ozone
Abstract:	A method and an apparatus for continuously treating an organic compound contaminated soil heap with an ozone containing gas using a closed loop gas recycle system.
Inventor(s):	Hater; Gary R. (Cincinnati, OH), Green; Roger B. (Cincinnati, OH)
Assignee:	Waste Management, Inc. (Oak Brook, IL)
Filing Date:	Sep 29, 1995
Application Number:	08/536,428
Claims:	1. A method for destroying organic contaminants in organics contaminated soil comprising the steps of; (a) forming organic contaminated soil into a soil heap covering one or more ozone recirculation piping systems and one or more vacuum withdrawal piping systems; (b) adding a first ozone containing gas stream into the organics contaminated soil heap using one or more ozone recirculation piping systems; (c) withdrawing a second gas stream from the contaminated soil heap using one or more ozone vacuum withdrawal piping systems wherein the concentration of ozone in the first ozone containing gas stream is higher than the concentration of ozone in the second ozone containing gas stream; (d) admixing the second ozone containing gas stream with ozone from a pressurized ozone source to give the first ozone containing gas stream; and (e) recycling the first ozone containing gas stream into the organics contaminated soil. 2. The method of claim 1 wherein the organics contaminated soil contains at least one of the organics contaminants selected from the group consisting of, coal tar, crude oil, refinery intermediates, creosote, kerosene, gasoline, #2 diesel fuel, heating oil, and sludge. 3. The method of claim 1 wherein recycling of the first ozone containing gas stream into the organics contaminated soil heap is halted and microorganisms capable of decomposing residual hazardous organic waste are applied to the soil heap. 4. The method of claim 1 wherein the contaminated soil heap is covered with a gas impervious material before the first ozone containing gas stream is introduced into the organics contaminated soil heap. 5. The method of claim 1 wherein the soil heap formed in step (a) is pretreated by bioremediation before adding the first ozone containing gas steam into the organics contaminated soil in step (b). 6. A method for remediating organics contaminated soil comprising the steps of; (a) preparing a first lift of contaminated soil; (b) locating a first ozone recirculation piping system on the first lift of contaminated soil; (c) placing a second lift of contaminated soil on top of the first ozone recirculation piping system; (d) locating a first vacuum withdrawal piping system on top of the second lift of contaminated soil; (e) repeating steps (a) through (d) at least once to give an organics contaminated soil heap including a plurality of ozone recirculation piping system and a plurality of vacuum withdrawal piping system; (f) injecting a first ozone containing gas stream into the organics contaminated soil heap using the plurality of ozone recirculation piping systems; (g) withdrawing a second gas stream from the contaminated soil heap using a plurality of vacuum withdrawal piping systems wherein the concentration of ozone in the first ozone containing gas stream is higher than the concentration of ozone in the second gas stream; (h) pressurizing the second gas stream with a recirculation blower; (i) admixing the second ozone containing gas stream with ozone from a pressurized ozone source to give the first ozone containing gas stream; and (j) directing the first ozone containing gas stream into the contaminated soil heap. 7. The method of claim 6 wherein each ozone recirculation piping system is separated on the vertical from each vacuum withdrawal piping system by from about 3 to about 25 feet. 8. The method of claim 6 wherein the addition of the ozone containing gas is halted and at least one microorganism capable of decomposing hazardous organic contaminants is applied to the soil heap. 9. The method of claim 6 wherein at least one microorganism capable of decomposing hazardous organic contaminants is added to each soil lift and is allowed to react with the hazard organic contaminants for a period of time sufficient to destroy at least some of the hazardous organic contaminants before ozone is injected to the soil heap in step (f). 10. A method for treating soil contaminated with hydrocarbons comprising the steps of; (a) preparing a first lift of contaminated soil; (b) locating a first ozone recirculation piping system on the first lift of contaminated soil; (c) applying at least one microorganism capable of decomposing hydrocarbon contaminants and at least one microorganism nutrient to the first soil lift; (d) placing a second lift of contaminated soil on top of the first ozone recirculation piping system; (e) applying at least one microorganism capable of decomposing hydrocarbon contaminants and at least one microorganism nutrient to the second soil lift; (f) locating a first vacuum withdrawal piping system on top of the second lift of contaminated soil; (g) repeating steps (a) through (f) at least once to give a hydrocarbon contaminated soil heap including a plurality of ozone recirculation piping systems and a plurality of vacuum withdrawal piping systems; (h) introducing a first ozone containing gas stream into the contaminated soil heap using the plurality of ozone recirculation piping systems; (i) withdrawing a second gas stream from the contaminated soil heap using the plurality of vacuum withdrawal piping systems wherein the concentration of ozone in the first ozone containing gas stream is higher than the concentration of ozone in the second ozone containing gas stream; (j) pressurizing the second gas stream with a recirculation blower; (k) admixing the second gas stream with ozone from a pressurized ozone source to give the first ozone containing gas stream; and (l) directing the first ozone containing gas stream into the contaminated soil heap. 11. An apparatus for decomposing organic contaminants in a soil heap comprising; a soil heap including soil and organic contaminants; at least one ozone recirculation piping system each ozone recirculation piping system having an inlet attached to an ozone recirculation manifold and a plurality of perforated recycle pipe legs wherein all perforated pipe legs are located within the soil heap; at least one vacuum withdrawal piping system each vacuum withdrawal piping system having a plurality of perforations located inside the soil heap and an outlet attached to a vacuum withdrawal manifold; a recirculation blower having a blower inlet attached to the vacuum withdrawal manifold and a blower outlet; a gas recirculation header attached to the blower outlet and attached to the ozone recirculation manifold; and a pressurized source of ozone gas associated with the gas recirculation header. 12. The apparatus of claim 11 wherein the ozone gas recirculation piping system and vacuum withdrawal piping system are constructed of plastic pipes. 13. The apparatus of claim 11 wherein a knockout drum is located in the vacuum withdrawal manifold between the vacuum withdrawal piping system outlet and the recirculation blower inlet. 14. The apparatus of claim 11 wherein a plurality of ozone recirculation piping systems and a plurality of vacuum withdrawal piping system are located in the soil heap in vertically alternating layers. 15. The apparatus of claim 14 wherein each ozone recirculation pipe leg and each vacuum withdrawal pipe leg terminates at a distance between about 0.5 meters to about 2.0 meters from any edge of the soil heap. 16. The apparatus of claim 11 wherein the recirculation blower delivers from about 0.01 scfm/ton of soil to about 0.20 scfm/ton of soil at a pressure ranging from about 10" to about 60" of water. 17. The apparatus of claim 11 wherein the soil heap is covered by a material selected from the group consisting of synthetic impervious materials and clay. 18. The apparatus of claim 11 including a carbon absorption unit associated with the gas recirculation header. 19. An apparatus for decomposing organic contaminants in a soil heap comprising; a soil heap including soil, organic contaminants, at least one nutrient, and at least one microorganism capable of decomposing organic contaminants; at least one ozone recirculation piping system, each ozone recirculation piping system having an inlet attached to an ozone recirculation manifold and a plurality of perforated recycle pipe legs wherein all perforated pipe legs are located within the soil heap; at least one vacuum withdrawal piping system, each vacuum withdrawal piping system having a plurality of perforations located inside the soil heap and an outlet attached to a vacuum withdrawal manifold; a recirculation blower having a blower inlet attached to the vacuum withdrawal manifold and a blower outlet; an gas recirculation header attached to the blower outlet and to the ozone recirculation manifold; and a pressurized source of ozone gas associated with the gas recirculation header.