Liquid purification or separation – Processes – Including geographic feature
Reexamination Certificate
2000-06-29
2001-09-04
Smith, Duane (Department: 1724)
Liquid purification or separation
Processes
Including geographic feature
C210S752000, C210S760000, C210S908000, C405S128300, C405S128450
Reexamination Certificate
active
06284143
ABSTRACT:
BACKGROUND OF INVENTION
1. Field of the Invention (Technical Field)
The present invention relates to apparatuses for remediation of dissolved chlorinated hydrocarbons in aquifer regions by injecting micro-fine bubbles effective for active in situ groundwater remediation for removal of dissolved chlorinated hydrocarbon solvents and dissolved hydrocarbon petroleum products. Remediation of saturated soils may also be obtained by employment of the present invention.
2. Background Prior Art
There is a well recognized need to cleanup of subsurface leachate plumes in aquifer regions and contaminated sites including in particular, dry-cleaning establishments and U.S. Military Air bases. Applicant is aware of prior art devices that have used injection of air to facilitate biodegradation of plumes.
However there has not been shown apparatus for remediating a site in a controlled manner of poorly biodegradable organics, particularly dissolved chlorinated solvents with micro-fine bubbles including a multi-gas oxidizing agent.
In fact the Federal Agency (EPA, KERR Environmental Laboratory, ADA, Oklahoma) responsible for review of clean-up procedures at Marine Corp Air Base at Yuma, Ariz. has determined that there is no prior references which disclose the use of the present invention and has ordered independent pilot tests to provide test results confirming the results previously obtained by the present invention.
In U.S. Pat. No. 5,221,159, to Billings shows injection of air into aquifer regions to encourage biodegradation of leachate plumes which contain biodegradable organics together with simultaneous soil vacuum extraction.
In U.S. Pat. No. 5,269,943, METHOD FOR TREATMENT OF SOILS CONTAMINATED WITH ORGANIC POLLUTANTS, to Wickramanayake shows a method for treating soil contaminated by organic compounds wherein an ozone containing gas is treated with acid to increase the stability of the ozone in the soil environment and the treated ozone applied to the contaminated soil to decompose the organic compounds.
In U.S. Pat. No. 5,525,008, REMEDIATION APPARATUS AND METHOD FOR ORGANIC CONTAMINATION IN SOIL AND GROUNDWATER, to Wilson provides a method and apparatus for in-situ treatment of soil and groundwater contaminated with organic pollutants. It involves concentration of a reactive solution required to effect treatment of the contaminated area; injecting the reactive solution into one or more injectors that are inserted into the ground, scaled and positioned so as to assure flow and allowing reactive solution to flow through the contaminated area thereby reacting chemically. Preferably, the reactive solution is an aqueous solution of hydrogen peroxide and metallic salts.
In U.S. Pat. No. 5,178,755, UV-ENHANCED OZONE WASTEWATER TREATMENT SYSTEM, to LaCrosse ozonated liquid is mixed within a multi-stage clarifier system with wastewater to be treated and suspended solids are removed.
However, notwithstanding the teachings of the prior art, there has not been shown apparatus for remediating a site in a controlled manner of poorly biodegradable organics, particularly dissolved chlorinated solvents with micro-fine bubbles including an encapsulated multi-gas oxidizing agent. The present invention accomplishes this by employing microporous diffusers injecting multi-gas bubbles containing an ozone oxidizing agent into aquifer regions to insitu strip and rapidly decompose poorly biodegradable organics or to accelerate biodegradation of leachate plumes which contain biodegradable organics which overcomes at least some of the disadvantages of prior art.
SUMMARY OF THE INVENTION
The present invention relates to sparging apparatus for injection of oxidizing gas in the form of small bubbles into aquifer regions to encourage in situ remediation of subsurface leachate plumes.
In particular the present invention is directed to sparging apparatuses for employing microporous diffusers for injecting micro-fine bubbles containing encapsulated gas bubbles into aquifer regions to encourage biodegradation of leachate plumes which contain biodegradable organics, or Criegee decomposition of leachate plumes containing dissolved chlorinated hydrocarbons. The sparging apparatuses of the present invention, employing microporous diffusers for injecting an encapsulated multi-gas oxidizing agent, are particularly useful in that the apparatuses promote extremely efficient removal of poorly biodegradable organics, particularly dissolved chlorinated solvents, without vacuum extraction of undesirable by-products of remediation and wherein remediation occurs by employing encapsulated multi-gas oxidizing agent for destroying organic and hydrocarbon material in place with without release of contaminating vapors.
Unlike the prior art, the contaminated groundwater is injected with an air/ozone mixture wherein micro-fine air bubbles strip the solvents from the groundwater and the encapsulated ozone acts as an oxidizing agent in a gas/gas reaction to break down the contaminates into carbon dioxide, very dilute HCL and water. This system is known as the C-Sparge system.
The present invention, hereinafter C-Sparger system (tm) is directed to low-cost removal of dissolved chlorinated hydrocarbon solvents such as perc from contaminated soil and groundwater aquifers. The C-Sparger(tm) system employs microporous diffusers, hereinafter Sparge Points (R) for producing micro-fine bubbles containing an oxidizing agent that decomposes chlorinated hydrocarbons into harmless byproducts. The C-Sparger (tm) also incorporates pumps means for pumping the an multi-gas oxidizing mixture through the Spargepoint diffuse into groundwater in a soil formation; a bubble production chamber to generate bubbles of differing size, a timer to delay pumping until large bubbles have segregated from small bubbles by rise time, and a pump which forces the fine bubbles and liquid out into,the formation. The pump means intermittently agitates the water in the well in which the C-Sparger is installed which is effective to disturb the normal inverted cone-shaped path of the bubbles injected by the Sparge point through the soil formation and disperses them in a random manner, ensuring improved contact between the oxidizing agent (contained in each bubble) by stripping the pollutant from solution in the water into the mini-atmosphere contained in each bubble. The pulsing action promotes movement of the bubbles through the porous formation. It is the insitu stripping action and maintenance of low solvent gas concentration in the bubbles which increases the efficacy and speed (and resulting cost) of remediation of a site.
The apparatus of the present invention for removal contaminants from soil and an associated subsurface groundwater aquifer using microporous diffusers in combination with a multi-gas system are particularly useful in that the system promotes extremely efficient removal of poorly biodegradable organics, particularly dissolved chlorinated solvents, without vacuum extraction, and wherein remediation occurs by destroying organic and hydrocarbon material in place with without release of contaminating vapors.
In the present invention the microporous diffusers and multi-gas system comprises oxidizing gas encapsulated in micro-bubbles generated from microporous diffusers matched to soil porosity. A unique bubble size range is matched to underground formation porosity and achieves dual properties of fluid like transmission and rapid extraction of selected volatile gases, said size being so selected so as to not to be so small as to lose vertical mobility. In order to accomplish a proper matching, a prior site evaluation test procedure is devised to test effectiveness of fluid transmission at the site to be remediated.
The advantage of controlled selection of small bubble size promotes rapid extraction of selected volatile organic compounds, such as PCE, TCE, or DCE with an exceptionally high surface to gas volume ratio. The dual capacity of the small bubble production pulsed injection and rise time is matched to the short lifetime of an oxidative gas, such as ozone
Fish & Richardson P.C.
Hoey Betsey Morrison
Smith Duane
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