FIELD OF THE INVENTION

The present invention relates to the decontamination of soil or other contaminated media, more specifically through the application of a direct current electric field.

BACKGROUND OF THE INVENTION

Electrokinetic processes involve the movement of contaminant ions in contaminated media by imposition of a dc electric field. The anode and cathode, or multiples thereof, is placed in contact with the media, often through a porous barrier. The ions migrate towards the electrode of opposite charge through the porous barrier into a solution in between the porous barrier and the electrode. The contaminant ion is drawn out of the contaminant media and into the solution located between the porous barrier and electrode. The contaminant ion is then removed from the system by removal of the solution.

Electrokinetic processes (electrophoresis, electroosmosis, and electromigration) have been in use for remediation of contaminated soil and groundwater since the mid 1900's when Casagrande ( 1954) used electroosmosis for slope stability in a geotechnical engineering application. Electrokinetic techniques for the in situ treatment of soil are known. British Patent 512,762 discloses a process of this kind, used for de-watering clayey sediments under the influence of electroosmosis. U.S. Patent No. 2,831 ,804 discloses a process for the electrokinetic in situ treatment (electroreclamation) of agricultural soils for the desalinification thereof. Another patent that describes an electrokinetic remediation processes is Pool's US Patent no.

5,433,829. Pool discloses an electroreclamation process whereby heavy metals and cyanide contaminants are continuously removed from soils via these contaminants having the ability to move toward an electrode under the influence of an electric current. In the environmental field, the use of electrokinetics has primarily been used as an in situ technology due to the high cost of excavation (US patent No. 5,914,020 to Griffeth et l). Most often, the technology is limited to use in remediation of heavy metal contaminated soils due to the high disposal cost and lack of alternative remediation methods. Further, salt contamination of soil is a widespread problem in areas where oil and gas drilling occurs or has occurred. As with heavy metals, there are few remediation alternatives to "dig and dump" but disposal of salt contaminated soil is much less costly than heavy metals. This relatively low cost disposal option is likely why electrokinetics have not often been used for salt remediation. Excavation is an immediate solution as opposed to known electrokinetic processes which can take months when conducted in situ. Salt contamination is a large problem in areas where oil or gas drilling and production has occurred or is occurring. Saline brine from the earth often spilled onto the ground resulting in large volumes of contaminated soil. Drilling mud can also be contaminated during drilling operation with salt and requires disposal.

Landfills have filled up and regulations tightened causing insurance rates to increase to the point where "dig and dump" has become much more costly. In locations where the landfill site is located a long distance away from the remediation site soil trucking costs are prohibitively expensive. The problem with "dig and dump" is that the contaminated soil is merely moved from one place to another. An electrokinetic technology for salt removal from soil or drilling mud has yet to be commercialized. This is likely due to feasibility difficulties such as long remediation times and the low cost of "dig and dump". However, over the years, the costs of "dig and dump" have increased and the advent of certain technological improvements has made commercialization of electrokinetic soil treatment feasible.

The objective of electrokinetic remediation is to clean the soil so that it is once again fit for agricultural purposes or whatever requirement of the specific site regulations might dictate. The prior art processes still have drawbacks to their commercialization and usefulness, consequently, there still remains a need for a process which can provide an efficient washing/decontamination of soil which overcomes certain drawbacks of prior art processes.

One of the biggest hurdles in soil decontamination is that the contaminant levels must be reduced to regulatory guidelines in a relatively short period of time, hours or at most days instead of months. The cost of having personnel attend to a process taking months to complete is unworkable and simply not economically feasible except in a few rare cases.

Thus, there still exists a need for a more efficient soil remediation process which will allow for large scale implementation thereof.

SUMMARY OF THE INVENTION

In situ electrokinetic extraction of contaminants in soil has a number of problems which resulted in such processes being slow or not working. In situ soil conditions are often anisotrophic resulting in wide conductivity variances within the media. Clay conducts an electric current while sandy and gravelly soils can lack conductivity.

Large stones, garbage, metal, and other impediments can impede an in situ process. By conducting the process ex situ such impediments can be removed. Further, soil moisture content is difficult to control "in situ". Injection of water into heavy clay is extremely difficult, if not impractical. Moisture content is more easily controlled ex situ.

The present invention overcomes a number of problems related to feasibility of electrokinetic processes for remediation of salt contaminated soil, drilling mud and drill cuttings.

Accordingly, the present invention is generally directed to a process for removing of ions from a contaminated media by applying a DC electric field between at least one anode and one cathode, wherein said process comprises the steps of:

a) providing a non-conductive treatment cell comprising: an anode chamber; a cathode chamber and a cavity located between the anode chamber and cathode chamber and separated from the two by the presence of a porous material; wherein said anode chamber comprises an anode and said cathode chamber comprises a cathode;

b) placing said media into said cavity;

c) introducing an electrolyte into said cavity filled with media;

d) submerging the anode and the cathode in their respective chambers with electrolyte; e) applying a DC current to the electrodes sufficient to cause migration of contaminant ions present in the media from the media to the electrolyte within the electrode chamber;

f) removing the electrolyte from the electrode chamber; and

g) optionally, removing the contaminant ions from the electrolyte.

According to a preferred embodiment of the present invention, at least one media conditioner is added to the media. Preferably, the media conditioner is selected from the group consisting of: water, clay, and chelating agents. More preferably, the chelating agent is EDTA.

Preferably, the electrolyte is decontaminated and/or recirculated back through the chamber. Preferably also, the cell and anode chamber and cathode chamber are enclosed within a tank. According to a preferred embodiment, the anode is a carbon graphite plate. According to a preferred embodiment, the cathode is a steel plate.

According to another aspect of the present invention, there is provided a system for ex situ electrokinetic treatment of contaminated media and remove ion contaminants wherein said system comprises:

an anode chamber comprising an anode and a first electrolyte;

- a cathode chamber comprising a cathode and a second electrolyte;

a power source to provide electrical current;

a tank adapted to be mounted on a skid or a trailer, wherein said anode chamber and cathode chamber are placed inside the tank separate from one another and define a cavity adapted to receive said media and said power source is in electrical connection with the anode and the cathode.

Preferably, the tank comprises drainage apertures located proximate the bottom of the tank, said drainage apertures adapted to discharge the electrolyte and contaminant ions. More preferably, the inside surface of the tank is made of non-conductive material. Preferably, there is also the presence of extraction means to remove chlorine gas produced at the anode. Preferably, the system further comprises treatment means to treat the chlorine gas produced at the anode. More preferably, the treatment means comprise a sodium hydroxide solution to contact the chlorine gas to convert a portion or all of the chlorine gas into sodium chloride and bleach.

According to a preferred embodiment of the present invention, the electrode chambers are adapted to receive a 45 degree angle cap on their top edge (over the anode chamber and the cathode chamber) to prevent media from being introduced into the chambers while loading such in the tank.

According to a preferred embodiment of the present invention, the process further comprises the step of amending the media prior to its introduction into the treatment cell. Preferably, the media is excavated prior to being amended. More preferably, a sample of the media undergoes laboratory testing to determine at least one of the characteristic selected from the group consisting of: conductivity of the media, contaminant concentration in the media, clay content in the media and moisture content in the media. Even more preferably, the excavated media is sieved prior to being amended. Yet, more preferably the excavated media is mixed to ensure uniform conductivity prior to undergoing laboratory testing. Conducting the electrokinetic remediation process ex situ allows for the media to be homogenized thus ensuring relatively uniform conductivity. The ex situ process also allows for the management and manipulation of variables such as moisture content, pH, clay content, electrode spacing, electrolyte composition and even temperature in a controlled modular process unit.

According to another aspect of the present invention, there is provided a process for reusing decontaminated media for agricultural operations, said process comprising the steps of:

providing a cell comprising: an anode chamber; a cathode chamber and a cavity located between the anode chamber and cathode chamber and separated from the two by the presence of a porous material; wherein said anode chamber comprises an anode and said cathode chamber comprises a cathode;

placing contaminated media into said cavity;

introducing an electrolyte into said cavity filled with contaminated media; submerging the anode and the cathode in their respective chambers with electrolyte; applying a DC current to the electrodes causing the contaminant ions present in the media to migrate from the media to the electrolyte within the electrode chamber; removing the electrolyte from the electrode chamber;

optionally, removing the contaminant ions removed from the electrolyte; and optionally, adding nutrients to the substantially decontaminated media. Preferably, the nutrients are added to the electrode chamber. More preferably, the nutrients are added to the media. Yet, more preferably, the nutrient is added when the media is deemed decontaminated.

Preferably according to one aspect of the present invention, the application of the DC current stimulates bacterial degradation of hydrocarbon contaminants present in the contaminated media.

According to an aspect of the present invention, the applied electric field causes the contaminant ions to migrate out of the media and into solution separated from the media through a porous barrier. The contaminant is then removed from the system by removing the solution from the electrode chamber.

Certain advantages of the process according to the present invention flow from conducting the process ex situ instead of in situ. This enables control over the media that is being remediated. Manipulation of the media enables considerable improvements in process optimization. Preferably, the process according to a preferred embodiment of the present invention was adapted to be conducted with equipment that is mobile, modular for transportability and scalability.

Preferably, soil conditioning agents and electrolytes can be added to excavated soils during an ex situ treatment according to the present invention. Typical electrolytes used in the process according to the present invention include water and various water-based electrolytes.

The remediation time can be decreased through increased process efficiency. The present invention overcomes the difficulties encountered with soil anisotropy in situ. Such difficulties, which include conductivity variations due to differing soil characteristics, decrease the process efficiency and increase the process time. Target contaminant ions move out of the areas with good conductivity but remain in areas with low conductivity. Such variations in the soil result in extended remediation times or even, incomplete soil remediation. Moreover, process completion time is a critical factor in relation to commercial feasibility or applicability thereof. An advantage of the process according to the present invention is the excavation of the media

(such as soil) and performing the process "ex situ" as it allows for the media to be modified. It is much less expensive to perform an electrokinetic process in situ but such a process does not work very well in situ because of the lack of control over the media. The inventors have discovered that soil homogenization; addition of soil conditioners and adjusting the moisture content can increase process efficiency resulting in substantially reduced remediation time. Soil conditioners are selected from the group consisting of: water, clay, and chelating agents such as EDTA. Homogenization allows eliminating zones of low conductivity and removal of things such as large stones, metal, garbage or other impediments to the process. Homogenization also mixes in the soil conditioners such as water, clay, and other possible amendments such chelating agents like EDTA to increase contaminant ion mobility. EDTA or other chelating agent is generally used for heavy metal remediation to help stop metals from precipitating or to maintain them in ion form.

The moisture content was found to have an impact on the soil remediation process. Preferably, the moisture content of the soil should be such that the soil is considered to be semisaturated to saturated. Preferably, a minimum moisture content of 12% is required for the electrokinetic process to operate at a minimum effectiveness range; optimum moisture content is a function of the numerous variables already identified and pre-process soil testing is conducted to optimize those variables in the process unit.

Preferably, in order to reduce the remediation time the electrode surface area can be increased and/or the distance between anode and cathode reduced. Preferably, the distance between the anode and the cathode ranges from 30 to 70 cm.

Preferably, the volume of soil that can be treated at once by a module can range from 15 m ³ to 50 m ³ . As this is a modular process, the process capacity can be adapted to vary with the specific requirements of the remediation project as well as the resources available on site. A single module capable of remediating soil, drill cuttings and drilling related mud slurries can have a minimum process capacity of approximately 15 m ³ . However, scalability allows a solid module to expand to 35m ³ if required and slurry units can be in the order of 50 m ³ per module. Preferably and depending on the project, multiple modules can be employed depending on the specifics of the project.

Preferably, the electrolyte in the fluid surrounding the electrode can be adapted to increase process efficiency. More preferably, any ions introduced into solution will increase the conductivity of the solution. Preferably, in the cathode chamber acetic acid is used to control pH, and dolomite (CaMg(C0 ₃ ) ₂ ) is added to the anode chamber. A small amount dolomite can be used initially to increase conductivity in the anode chamber. The acid in the cathode chamber sufficed to increase conductivity. In preferred embodiments, dolomite can be added near the end of the process to maintain conductivity. Alternatively, gypsum (CaS04) can also be used to attain the same result. Dolomite near the cathode is not recommended as the production of OH might lead to the formation of cement like products. In general, these products are only used in small amounts at the very end of the process and are not required when processing drilling mud. According to an aspect of the present invention, nutrient ions such as KN0 ₃ can be added to the process either in the electrode chambers or added directly into the media as the remediation process nears completion.

BRIEF DESCRIPTION OF THE FIGURES

The present invention may be better understood in consideration of the following description of various embodiments of the invention in connection with the accompanying figures, in which:

Figure 1 is a perspective view of the remediation tank used in the device according to a preferred embodiment of the present invention.

Figure 2 is a close up view of the swivel lock on the remediation tank used in the device according to a preferred embodiment of the present invention.

Figure 3 is a perspective view of an electrode chamber used in the device according to a preferred embodiment of the present invention.

Figure 4 is a front view of an electrode chamber containing an electrode used in the device according to a preferred embodiment of the present invention.

Figure 5 is a top view of an electrode chamber used in the device according to a preferred embodiment of the present invention.

Figure 6 is a perspective side view of the remediation tank mounted on a trailer used in the device according to a preferred embodiment of the present invention.

Figure 7a is a picture of soil electrokinetically remediated according to a process of the present invention after planting grass seeds.

Figure 7b is a picture of soil electrokinetically remediated according to a process of the present invention 9 days after planting grass seeds.

Figure 7c is a picture of grass growing after 1 month from the time of grass seed planting in soil electrokinetically remediated according to a process of the present invention.

DESCRIPTION OF PREFERRED EMBODIMENTS OF THE PRESENT INVENTION

The configuration for a system of electrokinetic soil remediation has been optimized by adjusting and maximizing the surface area of the electrode plates to increase the efficiency of the process. Preferably, the electrode surface area spans the width and height of the tank in which the contaminant media is placed and the distance between anode and cathode is reduced to be in the range of approximately 30-70cm.

A preferred embodiment of the present invention provides for an electrokinetic soil remediation system capable of removing contaminant ions selected from the group consisting of: chloride ions, sodium ions, nitrate ions, and metal ions. More specifically, the metal ions that can be removed with the electrokinetic soil remediation system according to a preferred embodiment include, but are not limited to: lead, arsenic, zinc, cadmium, copper, nickel, mercury, palladium, and chromium. The contaminated media requiring solid remediation can be soil, drilling mud or any other contaminated media.

According to a preferred embodiment of the present invention, the anode chamber is isolated from the cathode chamber by insulating any contact to the tank. The inside surface of the tank was coated with nonconductive commercial coatings to provide isolation of the media being processed from any possible interference in conductivity from the process tank. Preferably, to render the materials non- conductive, one can spray on a box-liner type of material or, even more preferably, use ceramic coatings which are nonconductive but are also more abrasion resistant. Another option can be to use a polymer tank configuration which would also eliminate and possibility of current density loss from the process to the process containment system. These are but a few of the various options to provide a non-conductive process tank.

The anodes and cathodes are suspended in their respective electrode chambers, which are preferably made out of nonconductive commercially available open mesh gratings, via additional isolative material so as to eliminate any process interference. Preferably, the mesh gratings (32) are made of fiberglass resin. Figures 3, 4 and 5 illustrate an electrode chamber (30) according to a preferred embodiment of the present invention to be used in the tank (10) illustrated in Figure 1. Figure 5 shows the size of the cavity (36) of the chamber (30) in which is inserted the electrode. The top edge (34) of the chamber (30) accommodates a cap (not shown) which prevents media from entering the electrode chamber (30) when filling the tank (10).

Figure 2 is a close up of the swivel lock (25) which, when unlocked, allows the tank (10) to swivel and dump its contents on its side. As illustrated in Figure 6, the system can be mounted on a trailer (45) for ease of transport to reach remote areas.

The inside surface (20) of the tank (10), made up of side walls (16 and 18) and end walls (12 and 14), is coated with a non-conductive material in order to eliminate any negative impact it could have on the process.

As best seen in Figure 4, electrodes (40) are inserted into the electrode chambers (30) which are covered with a permeable membrane (not shown) prior to being inserted vertically into the tank (10). The electrode (40) illustrated is a large metallic plate which allows for more efficient remediation. The permeable membranes can be made up of geotextile membrane for example. Moreover, there can be more than one layer of membrane to filter out finer material and coarser material. The efficiency of the membranes can be assessed by visual inspection of the liquid in the electrolyte chambers, as it should remain clear. According to an aspect of the present invention, there is provided a process that overcomes certain drawbacks of prior art processes. Certain preferred embodiments of the present invention will provide one or more of the following advantages over prior art processes: a tank adapted to be mounted onto a skid or onto a trailer such that the soil or media in a tank can be dumped once the remediation process is completed; a tank is mounted onto a skid or a trailer such that it is mobile and can be moved from site to site; the electrode chambers can be movable so as to be able to change the distance between anode and cathode; remediation time decreases with decreased distance between anode and cathode; adjustable spacing allows for significant process optimization; electrolyte and contaminant ions in the electrode chamber can be drained from the bottom of the chamber via holes in the bottom of the tank that are spaced at regular intervals to facilitate electrolyte drainage and variable electrode chamber spacing; and the modular design of the system allows for numerous units to be used on larger sites.

According to a preferred embodiment, a 45 degree angle cap is fitted over the electrode chambers (30) such that when the tank (10) is filled with soil or liquid media the media does not enter the electrode chamber. This cap is then removed once the tank has been filled.

According to a preferred embodiment, laboratory testing is conducted on a sample of the contaminated media. This testing includes: conductivity, contaminant concentration, clay content and moisture content. Bench scale electrokinetic trials are then conducted on the contaminated media in order to determine the parameters for large scale process optimization. The following steps can be performed during the bench scale trials:

the clay content, water content, is adjusted;

the contaminated soil or media is put through a screen or sieve to remove large rocks, garbage, or other materials that might impede or interfere with the remediation process; and

the contaminated soil or media is homogenized or mixed to ensure uniform conductivity.

According to an aspect of the present invention, there is provided a process for reusing the decontaminated media for agricultural operations, said process comprising the step of: adding nutrients to the electrode chamber or directly to the soil mid way or near completion of the remediation process. The nutrient ions are passed through the remediated soil to increase soil fertility subsequent to the remediation process. According to a preferred embodiment of the present invention, there is further provided a water treatment loop. This water treatment loop treats the effluent generated by the remediation process according to the present invention thus rendering the remediation process a closed loop process. The final effluent released from the process is treated to meet the regulatory acceptable discharge standards. The process effluent will then be treated in a water treatment process using at least one of the following: flocculation, chemical additives, filtration reverse osmosis or other processes as required meeting regulatory approved discharge guideline, as a minimum standard. According to a preferred embodiment, the electrokinetic process will stimulate bacterial degradation of said hydrocarbon contaminants present in the contaminated media. Bacterial degradation of hydrocarbons is one effect. Another effect is that of biocoagulation of suspended solids through a combination of electrokinetics and nutrients. According to a preferred embodiment, the electrokinetic process will stimulate the biocoagulation of suspended solids through a combination of electrokinetics and additives.

Example 1 - Electrokinetic Remediation of salt contaminated soil

A large scale trial was conducted on roughly one cubic meter of salt contaminated soil (>15,000 ppm NaCl). Remediation of this soil to less than 300 ppm of NaCl was accomplished in 4 days. A steel metal grating served as the cathode and supported the weight of the soil. Carbon electrodes served as the anodes and were placed on top of the material. Liquid was extracted from the top and bottom to facilitate contaminant removal. Bench laboratory trials were able to decrease the remediation time to hours. Ions migrate at a certain rate and the electromagnetic field strength varies with distance. Different soils act differently (even with additives) but, in general, the distance is determined, in part, by the way electrokinetic phenomenon works and, in part, by physical constraints on the technology. The shorter the distance between electrodes the faster the process works but the volume of soil between anode and cathode is reduced as the distance between anode and cathode decreases.

Water was employed as the electrolyte to start the process. The interface between the electrolyte (water) and the contaminated material provided the initial conductivity. As the process progressed, the conductivity of the water (electrolyte) increased. Care was taken to monitor and manage the electrolyte composition and conditioners used. The electrolyte composition and conditioners (additives) used are a function of the contaminant extraction rate, the pH and the volume of electrolyte with the additives already mentioned.

Example 2 - Reuse of electrokinetically Remediation salt-contaminated soil

In one trial, a cube of salt contaminated soil ( >10,000 ppm NaCl) was cleaned to reach a post- treatment concentration below 300 ppm of NaCl. The trial used a carbon-based electrode as the anode and a steel electrode as the cathode and water as the electrolyte at the start of the process. Figure #7a shows the soil the day grass seeds were planted in the soil that was electrokinetically washed according to a preferred embodiment of the present invention. Figure #7b shows the soil where grass had already started to flourish on the 9 ^th day after planting the seeds and Figure #7c shows the soil with substantial grass growth after one month from planting.

Example 3 - Electrokinetic Remediation of drilling mud

Salt contamination is a large problem in areas where oil or gas drilling has occurred or is occurring. Saline brine from the earth often spills on the ground and results in large volumes of contaminated soil. Drilling mud is often contaminated with salt and requires proper disposal.

Electrokinetic laboratory trials were conducted on drilling mud which showed the process to be effective on media other than soil. These trials led to the reduction of contaminant concentration in mud containing 10,000 ppm NaCl to less than 1000 ppm in 12 hours. After successful laboratory trials, a larger scale field trial was conducted on drilling mud. The trial used a carbon-based electrode as the anode, a steel electrode as the cathode and water as the electrolyte at the start of the process.

Salt contaminated mud from drilling operations was placed into the mud tank on site at a drilling location in Southern Saskatchewan. An array of anode and cathode wells were placed into the mud tank and a DC current applied. The applied power was 1500 Watts for a period of 8 hours. Extraction rates from the mud in the field scale trial were similar to results produced in the laboratory. Extraction rates vary with contaminated material concentration, characterisation as well as from the beginning to the completion of the process.

Electrode spacing and electrolyte composition have a direct impact on the extraction rate. Recent tests have shown chloride extraction rates of 1 100- 1400 mg/L per hour and salt extraction rates of 3500- 5700 mg/L per hour in non-optimized conditions. The work done with this technology focused mainly on salt removal from drilling mud associated to oil and gas operations or other drilling operations, but can be adapted to remediate the media from other ions such as nitrate or various heavy metals. Example 4 - Commercial Quantities Testing

Further to the initial field trials described in example # 3, a commercial scale module consisting of seven electrolyte chambers and six treatment cavities was developed capable of providing a potential treatment capacity of 1 cubic meters. Initial field testing was conducted in a drilling mud application. The cathodes used in field testing were carbon graphite as testing showed that with increase current the carbon fibre degraded at a rapid rate making less desirable for the application. The anode was made of steel. The surface area of the anodes and cathodes is in the order of 1800 square feet up from 120 sq. feet in example number 3 The bench top testing had shown that sodium ions levels could be reduced from 1630 mg/kg to 151 mg/kg in three hours and down to 43 mg/kg after 5 hours of soil remediation. Likewise chloride ions were reduced from 7840 mg/kg to 2360 mg/kg to 157 mg/kg during the same test. Electric conductivity on the material was reduced from an initial EC of 34.1 dS @25°C to 2.48 dS @ 25°C after five hours. The tests were performed on average at 80 volts and 6 amps while dealing with 6 kg of material. The test bed was two 4 inches by 8 inch anodes and one similar sized cathode. The test was repeated and the results were confirmatory. The commercial scale unit that was developed comprised seven electrode chambers, four anodes and three cathodes. The anodes are steel plates measured four feet by 3 and a half feet and the cathodes are carbon graphite that measure 4 feet by 32 inches. The electrode chambers are eight inches wide and the cavity between the electrode chambers is 22 inches. The electrode chambers hold 1.3 m ³ of electrolyte and the treatment cavities holds up to 16 m ³ of material to be treated. Another commercial scale unit was manufactured and comprises nine electrolyte chambers and a capacity of 20 m ³ . Two 45 kW power supplies (100 V and 450 amp each) and 125 kW generator power the two module 36 m ³ commercial process unit.

A soil remediation carried out during the commissioning testing, extraction rates obtained in the first two hours exceeding the predicted extraction rates. The base line in the field test was EC of 62.40; sodium ions present at 4,200 mg/kg; chloride ions present at 20,000 mg/kg; and calcium ions present at 1680 mg/kg. After two hours of processing, the EC had decreased to 46.5; sodium ions down to 2900 mg/kg; chloride ions down to 10,000 mg/kg; and calcium ions down to 960 mg/kg. Based on this initial scale testing, adequate remediation is achievable within six hour remediation time.

Example 5 -

Cuttings were supplied and a process of electroremediation was carried out. Initially the cuttings were evaluated for, Sodium, Chloride and Nitrate concentrations. The sodium concentration was 71 1 mg/kg, while the chloride was 945 mg/kg and nitrate concentration was of <5.6 mg/kg.

The supplied cuttings were placed into the test chamber and the electroremediation process was carried out. Liquid from the anode and cathode was collected and tested for sodium and chloride concentration as the nitrate concentrations were below valid test concentrations. The ion concentration observed over the course of the test procedure is shown in Table 1

Table 1

Time Sodium Chloride

(mg/kg) (mg/kg) 30 min 240 200

60 min 330 345

90 min 540 450

These results represent ion transfer to process electrolyte

The trial showed that cuttings are amenable to the process according to a preferred embodiment of the present invention in that the ions are able to migrate from the cuttings into the electrode chamber under the influence of an electric field even at these low concentrations.

The process efficiency was noted to decrease at low ion concentrations. For this reason, assessment of the suitability of a given contaminated material to a process according to the present invention may in some instances be better done with media that are more contaminated and some previous test results are provided in the following tables to illustrate.

Table 2 - Soil Results

*These results are based on soil samples taken post treatment.

Table 3 - Drilling Mud Bench Test Results

* These results represent mud sample test

Table 4 - Drilling Mud Field Test Results

Time Sodium (mg/kg) Chloride (mg/kg)

in mud in mud

Initial (0 min) 240 5040 60 min 200 4500

120 min 180 3710

These results represent mud sample test Table 5 - Field Soil Test Results

Parameter Before Onsite Process After two hours of

Electroremediation Process

Electric conductivity (@25C) 39.9 dS/m 20.0 dS/m

Sodium Absorption Ratio 40.4 19.6

Sodium Concentrations 9820 mg/kg 3330 mg/kg

Chlorides Concentrations 22,000 mg/kg 5510 mg/kg

" hese results are based on soil samples taken post treatment.

In recent equipment commissioning tests, not only was the first module of the commercial unit commissioned successfully, the test also validated the scalability of the process. Much like the cutting samples supplied, the commissioning tests did not represent highly contaminated materials but the data presented in Table 1 does show the validity of the process.

According to one aspect of the present invention, the components used in the process were designed to fit onto a skid or onto a trailer and to accommodate the loading and unloading of soil, drilling mud, or other media. A system of pumps, valves and manifolds are utilized to facilitate the easy transfer of the anode and cathode electrolytes into and out of the electrode chambers. The electrolyte, once charged with contaminants from the process media, is then extracted from the electrode chamber through a system of pumps, valves and manifolds to an effluent tank. The process effluent is subsequently treated in a water treatment process using at least one of the following: flocculation; chemical additives; filtration; reverse osmosis; or other processes as required to meet a regulatory approved discharge guideline, as a minimum standard.

The terms and descriptions used herein are set forth by way of illustration only and are not meant as limitations unless otherwise specifically indicated. Those skilled in the art will recognize that many variations are possible within the scope of the invention as defined in the following claims, and their equivalents, in which all terms are to be understood in their broadest possible sense unless otherwise specifically indicated.