METHOD FOR IN SITU SOIL
This is a continuation-in-part of application Ser. No. 08/057342 filed on May 3, 1993, now abandoned which is incorporated herein by reference.
FIELD OF THE INVENTION
The invention relates to a method and an apparatus for the in situ remediation of contaminated soil or sludge.
BACKGROUND OF THE INVENTION
It is widely recognized that years of unregulated industry have produced numerous environmentally hazardous sites throughout the country and the world which pose substantial health hazards to world's population. In recent years, efforts to clean up or remediate environmentally contaminated sites have increased dramatically, and numerous methods and devices for cleaning up or disposing of environmental contamination have been devised or proposed. However, the magnitude of the environmental problems is enormous, but the resources available to solve the problems are limited. Therefore, there is an urgent need for methods of remediation that are relatively uncomplicated, may be rapidly implemented, and are technically and cost effective.
Therefore, it is an object of this invention to provide a cost effective, relatively rapid method of remediating environmentally contaminated sites.
It is another object of this invention to provide a highly mobile apparatus for remediating environmental contaminants.
It is yet another object of this invention to provide a method of remediating contaminated soil in situ and without removal or disposal of the treated or contaminated material.
It is yet another object of the invention to provide a method that is capable of remediating contaminated soils and sludges in a continuous, in contrast to a batchwise, manner.
It is yet another object of the invention to provide a remediation apparatus and method which may be used on highly unstable soils and in tight quarters such as in the basements of buildings or near above-ground or belowground storage tanks.
The above objects and advantages of the present invention will become more apparent when reference is made to the foEowing description taken in conjunction with the accompanying drawings.
SUMMARY OF THE INVENTION
Contaminated material such as soil or sludge is remediated by injecting a suitable remediation fluid into the material during excavation of the contaminated material with a trenching tool. The remediation fluid is injected into the contaminated material through an injection means, preferably a plurality of injection nozzles positioned along the length of the trenching tool. The thusly treated material is backfilled or deposited directly into the trench excavated by the trenching tool thereby obviating the need for off-site disposal. The constituent remediation agents in the remediation fluid may be adjusted to adapt to varying site conditions and contaminants. The remediation fluid may also be heated to accomplish volatile stripping of the contaminated material or to activate microbial agents in a low temperature environment.
In one aspect, the present invention is an injection treatment apparatus for remediating contaminated material at a
contaminated site having a trenching mechanism means with a trenching tool and a means for positioning and powering the trenching tool. The apparatus has
an injection means for injecting a remediation fluid into
5 the contaminated material in close proximity to the trenching tool and a remediation fluid delivery means for conveying and deEvering the remediation fluid to the injection means under pressure. The injection means has at least one injection nozzle,
10 preferably a pluraUty of injection nozzles, positioned to inject the remediation fluid into contaminated material excavated during operation of the trenching tool. The injection nozzles are preferably located at predetermined positions along the length of the trenching tool.
15 The remediation fluid deEvery means has a remediation fluid storage means, a conduit means and a pump means for pumping the remediation fluid from the storage means through the conduit means to the injection means under pressure. OptionaEy, the remediation delivery means may
20 have a heating means for heating the remediation fluid such as in the case of forced hot air.
The apparatus may also have a monitoring means for monitoring a selected physical or chemical property of the contaminated material such as pH, oxygen content, tempera
25 ture or the Eke in the proximity of the trenching tool during operation of the apparatus and a means for adjusting the selected property of the contaminated material to a predetermined value, such as a means for adjusting the amount of a constituent remediation agent in the remediation fluid
30 injected into the contaminated material during operation. The apparatus may also comprise a volatile coUection means for collecting volatile substances such as volatile hydrocarbons emitted from the contairiinated material during treatment with the injection treatment apparatus.
35 In another aspect, the invention comprises a method for remediating a contaminated material at a contaminated site. The method comprises agitating the contaminated material with a trenching tool mechanism having a trenching tool and contemporaneously injecting a suitable remediation fluid
40 into the agitated or excavated contaminated material in the proximate vicinity of the trenching tool to provide a treated material. The treated material is preferably deposited into the trench excavated by the trenching tool mechanism. Where the contaminated material comprises a volatile
45 constituent, the remediation fluid is preferably a fluid such as hot air for volatilizing a volatile constituent which is then coEected using a coUection means. In the case of a Equid or semi-soEd contaminated material such as a sludge or wastewater lagoon, the remediation fluid preferably comprises a
50 soEdification agent which is injected into the contaminated material thereby soUdifying it and permitting further treatment. The method may also comprise monitoring a selected physical or chemical property of the contaminated material such as pH, oxygen content, temperature or the Eke and
55 adjusting the selected property of the contaminated material to a predetermined value such as a value determined necessary or sufficient to environmentaEy remediated the contaminated material. For example, the pH may be maintained at a predetermined value by adjusting the amount of a
60 constituent pH adjusting agent such as a pH buffer solution in the remediation fluid. The method may also comprise the step of heating the remediation fluid prior to injecting it into the contaminated material. This is useful where the remediation fluid comprises a microbial bioremediation agent and
65 a gas such as air is heated sufficiently to activate the bioremediation agent in the contaminated material in a low temperature environment.