OA11744A - Process and composition for treating hydrocarbon contaminated material. - Google Patents

Abstract

A composition for treating materials contaminated with hydrocarbon compounds comprises a protein component, a bulking agent and a microbial culture capable of metabolizing the hydrocarbon contaminants. The composition is mixed with the contaminated material and absorbs or adsorbs the contaminants thereby preventing leaching of same into the environment. The microbial culture allows for biodegradation of the contaminant thereby removing any environmental risk associated with the contaminated material. The protein component and bulking agent are preferably organic in nature and the microbial culture may be indigenous to the protein material. The invention also provides a method of treating hydrocarbon-contaminated material using a composition as described above. The invention is particularly suited for treating contaminated drill cuttings.

Description

11 7 4 4

Process And Composition For Treating HydrocarbonContaminated Material

BACKGROUND OF THE INVENTION

1. FIELD OF THE INVENTION

The présent invention relates to methods for treating materials contaminated withhydrocarbon substances and to compositions for such method. The invention is particularlyrelated to oil contamination in drill cuttings generated from drilling well bores.

2. DESCRIPTION OF THE PRIOR ART

Oil contamination of land and water has become a major environmental problem.

Many instances hâve been encountered where ecosystems hâve been severely damaged due tothe accidentai spillage of oils or other hydrocarbon compounds.

One area where oil contamination is regularly encountered is in bore-hole drillingSystems either on or off shore. In the drilling process, oil contaminated drill cuttings arebrought to the surface and collected. The cuttings and other material brought to the surfacemust be treated to remove the oil contaminants in order to prevent them from seeping into thesoil or from being dumped into the water.

In order to address this problem various solutions hâve been proposed such as, forexample, buming the cuttings or washing them with a detergent solution. The first methodresults in both safety and environmental risks. The second method involves a long processtime and, possibly, further contamination risks depending upon the detergent used.

In US patent 4,242,146, a method for treating oil contaminated drill cuttings from offshore drilling units is taught. In this patent, the contaminated cuttings are contacted with anoil absorbent substance such as clay in order to remove any free oil. The combination ofcuttings and absorbent is then retumed to the water. This reference does not teach a methodof removing the oil contaminant but merely to absorb and free oil from the cuttings.

Various other references teach methods for treating oil spills on water bodies. USpatent 4,925,343 teaches a composition for cleaning oil spills comprising a particulatemixture of wood fïber and hydrophobie cotton lint materials. Similar methods are taught inUS patents 4,061,567 and 3,617,564. These references teach the use of synthetic or naturalfibers for absorbing hydrocarbon contaminants from water or land. 1 717 4 4

Although addressing the oil spill these references do not deal with degrading thehydrocarbon contaminant to completely remove the contamination risk. US patent 5,395,535 teaches a process for removing hydrocarbon materials fromwater or land comprising spreading dried plant or vegetable matter over the spill. Cotton gin“trash” or waste is indicated as material for use in this process. The cotton material is spreadover the oil spill to absorb and retain the contaminant. The material with absorbed oil is thenallowed to ferment wherein bacteria indigenous to the cotton material biodegrade thehydrocarbon contaminants. US patent 5,635,392 also teaches a process for treating oil-contaminated materialwherein microbial action is used to remove the contaminant. In this reference, a nutrientmixture, along with a microbial inoculum, is taught for addition to hydrocarbon contaminatedmaterial to stimulate the growth of the culture. In such manner, the contaminant is removedfrom the System.

Although the latter two references address the removal of the contaminant, the timetaken for such biodégradation may lead to spread of the contamination before the removal iscomplété.

Thus, a need exists for an efficient process for removing hydrocarbon contaminationon water or land and a process that accomplishes such removal while minimizing anyleaching of contaminants. Therefore, the présent invention seeks to provide a means of: - on-site containment and treatment of drilling residue. - on-site stabilization and immobilization of leachable hydrocarbons using onlyorganic absorbents. - on-site bioremediation of hydrocarbons through natural microbial biodégradation.

SUMMARY OF THE INVENTION

Therefore, in one embodiment, the présent invention provides a composition fortreating hydrocarbon-contaminated material including a protein component and a bulkingcomponent.

In another embodiment, the invention provides a process for treating hydrocarboncontaminated material with a treatment composition comprising a protein component, abulking agent and a microbial culture capable of metabolizing the hydrocarbon contaminant,the process comprising the steps of: 2 117 4 4 1) contacting the material with the treatment composition to immobilize thehydrocarbon contaminant; and, 2) biodegrading the contaminant with the microbial culture.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of the preferred embodiments of the invention will becomemore apparent in the following detailed description in which reference is made to theappended drawings wherein:

Figure 1 illustrâtes the total extractable hydrocarbon mass fraction profiles on Day 0and Day 41 under different additive conditions in the biodégradation tests.

Figure 2 illustrâtes the changes in total extractable hydrocarbon mass fractions after41 days under different additive conditions in the biodégradation tests.

Figure 3 illustrâtes the changes in initial total extractable hydrocarbon mass fractionsafter 41 days under control additive conditions in the biodégradation tests.

Figure 4 illustrâtes the oxygen uptake rate under different additive conditions in thebiodégradation tests.

Figure 5 illustrâtes the carbon dioxide production rate under different additiveconditions in the biodégradation tests.

Figures 6 and 7 illustrate the hydrocarbon réduction during the bioremediation fieldplot tests.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hydrocarbon contaminants according to the invention include any liquid contaminantthat is organic, leachable and hydrophobie in nature such as gasoline, oil, créosote, etc. Suchcontaminants may be found as spills on water or land or in soil substrates, i.e. litter, clay,shale, drill cuttings etc., contaminated by such liquid contaminants. By way of example, theprésent invention will be described in relation to the treatment of drill cuttings. However, itwill be appreciated that a variety of applications are possible for the invention.

As discussed above, the desired characteristiçs of a process for treating suchhydrocarbon contamination are speed of removal and efficient dégradation thereof of thecontaminants. For this reason, the présent invention provides, in one embodiment, atreatment composition for treating material contaminated by hydrocarbon contaminants as 3 117 4 4 described above whereby such contaminants are safely removed by biodégradation. Thecomposition of the invention comprises, as the active ingrédients, a protein component and abulking agent. In the preferred embodiment, the protein component and bulking agent areorganic in nature.

The treatment composition according to a preferred embodiment of the invention ischaracterized by its ability to: - Constitute a primarily organic matrix; - Develop, sustain and/or promote a consortium of indigenous or artificiallyinoculated microorganisms capable of metabolizing the hydrocarbon contaminants toacceptable limits; - Prevent hazardous movement (i.e. leaching) of contaminants when in a biopile orspread over a soil surface in the presence or absence of water; - Be spread over any uncontaminated surface or subsurface soil and to protect the oil-free integrity of the receiving soil at the time of spreading or incorporation andanytime thereafter.

In the preferred embodiment, the protein component of the composition servesvarious purposes. Firstly, it provides a source of indigenous microorganisms that hâve thecapability of biodegrading hydrocarbon contaminants. Secondly, the protein componentserves as a source of nutrients for the microorganisms conducting the biodégradation process.

In another embodiment, the required microorganisms may be comprise a separate additive tothe treatment composition to provide the required microbial culture or to supplément orcomplément the culture included in the protein component. Whether or not the proteincomponent provides a source of microorganisms is dépendent upon the sélection of theprotein material. For example, it is mentioned above that cotton waste provides a source ofindigenous hydrocarbon consuming microorganisms. Similar proteinaceous sources ofmicroorganisms may also be used. For example, suitable sources for the protein componentof the présent invention include canola (or râpe), soy, cotton, corn, or peanut material or fromother protein based material or any combination thereof. Generally, the protein componentcomprises organic protein meal.

Another preferred characteristic of the protein component is its ability to absorb oradsorb the hydrocarbon contaminant. This sorptive capacity aids in immobilizing thehydrocarbon thereby preventing leaching of such compounds out of the containment mix,which is the combination of the contaminated material and treatment composition. 4 117 4 4

Therefore, the protein component of the invention is characterized by its ability to: - Display sorptive capacity for a range of hydrophobie organic contaminants; - Act as an oleophilic sorbent; preferential to oil in presence of water; - Eliminate (immobilize) free liquid contaminants during blending/mixing processesand subséquent to spreading over land; - Supply a source of elemental nitrogen in the form of protein; - Alter the bulk density of liquid contaminants or contaminated substrates; - Provide a source of indigenous microorganisms capable of metabolizing thehydrocarbon contaminants; - Be readily available and accessible in large volumes; - Remain stable, non phyto-toxic or micro-toxic.

As mentioned above, the bulking agent is preferably organic in nature. The bulkingagent may comprise, for example, wood shavings, peat moss, straw, etc., or any combinationthereof. The main function of the bulking agent is to build structure in the containment mixand secondly to provide additional contaminant absorbency. Such structure results inefficient gas or air exchange properties. This is important since in biodégradation processes,aérobic conditions are necessary to maintain the desired accelerated levels of microbialactivity. Such conditions improve the efficiency of biodégradation, which is important whendealing with hydrocarbon contaminants. A single type of bulking agent or a combination ofseveral may be used. Ideally, the bulking agents are chosen on their ability to reduce theoverall bulk density of the containment mix and to provide appropriate conditions formicrobial activity.

In another embodiment, the invention provides a process for treating hydrocarbon-contaminated material using a composition as described above. In the first step, the processimmobilizes and stabilizes the contaminants in a homogeneous containment mixture. This isaccomplished by contacting the contaminated material with the treatment composition of theinvention as described above. Such contacting may be accomplished in a number of waysincluding mechanical or physical blending or mixing. The contacting phase serves to:

Achieve homogeneity (contaminant immobilization) on a macroscopie as well asmicroscopie level;

Dilute the contaminants with the treatment composition and other additives ifrequired; 5 117 4 4

Achieve the desired contaminant immobilization and bulking by the ability to adjustthe volume of the treatment composition;

Allow for the even incorporation of other additives to the mix such as microorganisminocula and/or additives (such as fertilizers, bionutrients, slow release oxygen agents,bioaugmentation agents, hydrocarbon washing/chain-severing agents, etc.) intended tostimulate or accelerate microbial activity in the containment mix.

In addition, the blending or mixing phase provides an opportunity to “wash” ordissolve soluble salts, metals, and other analytes from the contaminated material in order toalter the electrical conductivity, sodium adsorption ratio and pH of the containment mixproduced.

The immobilization step is used to prevent or reduce any leaching of the contaminant.Such leaching is quantified by the Toxicity Characteristic Leaching Procedure (TCLP) whichis a standardized leaching analysis test accepted by regulatory agencies. It is designed todétermine the mobility of both organic and inorganic analytes présent in liquid, solid andmultiphase wastes. The test is conducted as follows: for wastes containing greater than orequal to 0.5% solids, a minimum of 100g of solid phase sample is mixed with a volume ofwater equal to 20 times the weight of the solid phase. In this case, water is referred to as theextraction fluid. Characteristically, the water must be purified, de-ionized and organic-free.Sample préparation requires crushing, grinding and cutting if solids are greater than 9.5 mmin size. The mixture is placed into a specialized bottle extraction vessel with a minimumcapacity of 2L. The vessel is then placed into an agitation apparatus that rotâtes the vessel inan end-over-end fashion at 30 rpm for 18 hours. Following agitation, the mixture is pouredover a 0.6 to 0.8 pm glass fiber filter. The leachate is collected and analyzed for the presenceof hydrocarbons.

Following the immobilization phase, microbial activity in the containment mix (i.e.the mixture of the contaminated material, treatment composition and any other additives) isallowed to continue whereby the hydrocarbon contaminants are biodegraded. As mentionedabove, the source of the microorganisms for the biodégradation phase may be inhérent orintroduced. The protein component and bulking agent(s) constitute a primary source ofindigenous microorganisms. Further, in another embodiment, manure, sewer sludge, or anyother microbially active liquids or soils can also be used to introduce naturally-occurringmicroorganisms, capable of metabolizing hydrocarbons, to the containment mix during or 6 11744 following mixing. Also, genetically synthesized microbial inocula or cultures can also beused to introduce additional microorganisms into containment mixes during or followingmixing activities.

With the présent invention, hydrocarbon contaminants are disposed of safely withoutany further Processing while limiting or preventing any leaching of the contaminants duringthe course of biodégradation.

As mentioned above, the invention has been described in connection with treatingcontaminated drill cuttings. However, the process and composition of the invention cansimilarly be applied to oil spills on land or water or to other material affected by hydrocarboncontamination.

The following examples and tests are provided to illustrate the advantages of theprésent invention and are not to be considered as limitations thereof. 1) Roof-Top Leach Tests

To test the hydrocarbon immobilization and stabilization capacity of treatmentmixtures, specialized Roof-Top Leach Trays were designed. The objective was to develop atest to provide analytical evidence that petroleum hydrocarbons in samples remainimmobilized and impervious to leaching. Descriptions of the respective samples, or mixes,(nine were tested) are provided in the results discussed below.

The mix ratio is an expression of the proportion of Canola meal that is required totreat a specified amount of drilling residue. It is determined using the Agitation/FiltrationTest. The objective is to détermine if a suffîcient volume of Canola meal, acting as an oilabsorbent, is présent in the treatment mixture to effectively immobilize the total petroleumhydrocarbons associated with the mixture. The procedure for the agitation/filtration test is asfolio ws: 1) A treatment mixture is placed into a sealed container. Water is added at a ratio of 5parts solution to 1 part solids (residue), according to the following calculation:Conversion: An average of 500 mm of annual précipitation occurs over an area witha maximum depth of 10 cm (100 mm), therefore the conversion ratio is 500:100 or theéquivalent of 5:1 ratio of water to mixture. 2) The container is sealed and forcefully agitated for approximately 2 minutes. Whilesolids remain in suspension, the contents of the container are filtered through a funnelwith a fine mesh screen. The filtrate is collected in a clear container and analyzed forthe presence of a surface oil sheen. If présent, a sheen is an indicator that the mix 7 ratio used is not effective in completely immobilizing the hydrocarbon component ofthe particular mixture. 3) Subsequently, a mixing additive and re-trial is necessary.

The Roof-Top Leach Tray has a design similar to that of a steep pitched roof (30%slope) intended to simulate a worst case scénario. In total, a volume of 20 L of the samplemix is spread into each side of the leach tray (having dimensions 45 cm x 45 cm or 20 cm x20 cm) up to a maximum thickness of 10 cm. Mixtures are held in place by screens thatprevent the migration of solids but allow water flow freely. To simulate précipitation andrun-off conditions, water is sprayed over the mixtures.

Although this design may be considered a severe exaggeration of extreme siteconditions, the objective is to cause water to move quickly across and through the profile ofthe mixture to “wash” out ail poorly absorbed or excess hydrocarbons. Ail excess water wascollected as leachate in collecting trays equipped with drain plugs. The leachate wasanalyzed for the presence of petroleum hydrocarbons indicated by an oil sheen or sampled forlaboratory analyses.

As preliminary results proved favourable, hydrocarbon immobilization was testedusing the two tests discussed above: 1) the Agitation / Filtration Test and 2) the ToxicityCharacteristic Leaching Procedure (TCLP).

Results of Leach Tests

The following are the results from the analytical testing of samples from the filtrationand leach tests mentioned above. In total, nine samples were analyzed. The samplesrepresented a full range of leachates, filtrâtes and solids with varying Total PetroleumHydrocarbon (TPH) values.

To follow is an overview of sample descriptions, results of TPH tests, as well as aninterprétation of the results. 8 11744

Sample 1

Type Solid (500 ml) Mix Ratio No treatment Description A 500 ml (420g) solid sample of residue/hog fuel was collected for sampling. The sample was pure and received no treatment. Objective To provide an indication of the percentage (by weight) of total petroleum hydrocarbons présent in an untreated sample of JOMAX 4 residue/hog fuel mixture. Analysis 86,600 mg/Kg = 86,600 ppm = 8.66 TPH

Sample 2

Type Leachate (250 ml) Mix Ratio No treatment Description A 500 ml (420g) solid sample of residue/hog fuel was placed in a leach tray (20 cm X 20 cm). To the sample was added a total of 800 ml of water over 4 wettings to simulate the équivalent of 20 mm of rainfall. Of the total volume of leachate produced, a 250 ml sample was collected and analyzed. Objective To détermine the concentration of petroleum hydrocarbons that leach from an untreated sample of JOMAX 4 residue/hog fuel mixture caused by 20 mm of précipitation. Analysis 6 mg/L = 6 ppm = 0.0006 TPH 5 Sample 3

Type Solid (500 ml) Mix Ratio 4:1 (Residue: Râpe Meal) Mix by Volume 7:1 (Residue: Râpe Meal) Mix by Weight Description A 400 ml (336 g) sample of drilling residue/hog fuel was mixed with 100 ml (48 g) of râpe meal and placed in a leach tray (20 cm X 20 cm). To mimic an aboveaverage volume of rainfall, the mixture received a daily application of 200 ml ofwater over a period of 4 days. In total, 800 ml of water or équivalent of 20 mmof rain was sprinkled over the mixture (See Conversion). After 4 hours, leachinghad terminated. The solids were collected from the leach tray mid analyzed. 9 117 4 4

Conversion Area of Leach Tray = 0.20 m X 0.20 m = 0.04 m2 Max Average precip. = 5 mm = 0.005 m Volume precip. = 0.0005m X 0.04m2 = 0.0002 m^ X (1L/0.001 m^) = 200mL Objective To détermine the total volume of petroleum hydrocarbons that remain immobilized by solid particles (cuttings and râpe meal) during the simulation of 4 maximum précipitation events. Analysis 40,300 mg/Kg = 40,300 ppm = 4.03 TPH

Sample 4

Type Leachate (250 ml) Mix Ratio 4:1 (Residue: Râpe Meal) Mix by Volume 7:1 (Residue: Râpe Meal) Mix by Weight Description Of the total volume of leachate produced by the treatment of Sample 1. A 250 ml sample was collected for analysis. Objective To provide an indication of the total concentration of petroleum hydrocarbons leached expected to leach ffom a mixture during the simulation of 4 maximum précipitation events. Analysis 4 mg/L = <4 ppm = 0.0004 TPH

Sample 5

Type Filtrate (250 ml) Mix Ratio 4:1 (residue: râpe meal) Mix by volume 7:1 (Residue: Râpe Meal) Mix by Weight Description To produce a filtrate, 400 ml (336g) of residue was mixed with 100 ml (48g) of râpe meal and placed into a fine screened tunnel. To mimic the équivalent of 20mm of rain, 600 ml of water was poured over the mixture. After 4 hours,filtration appeared to hâve ceased and a 250 ml sample of filtrate was collected and analyzed. Objective To détermine the total volume of petroleum hydrocarbons that are dissolved and"washed" from a mixture as a resuit of normal hydrologie and gravitational forces acting upon the mixture. Analysis <4 mg/L = <4 ppm = 0.0004 TPH 10 11744

Sample 6

Type Filtrate (250 ml) Mix Ratio 4:1 (residue: râpe meal) Mix by Volume 7:1 (residue: râpe meal) Mix by Weight Description A 500 ml mixture of residue/hog fuel (400 mL/336g) and râpe meal (100 mL/48g) was placed into a seated 2.5 L container. The container was filled to capacity with 2.5 L of water, the équivalent of maximum volume of annual précipitation of 500 mm (Statistics Canada, 1997). The container was agitated for 2 minutes. Prior to settling, the suspended mixture was poured into a fine. screened funnel. After 4 hours, filtration was terminated. The tunnel was squeezed to force out any trapped water within the mixture. A 250 ml sample of the filtrate was analyzed. Objective Through direct comparison with the results from Sample 5, the immobilizing capacity for hydrocarbons of râpe meal and cuttings versus the influence of extreme hydrologie and gravitational forces can be determined. Analysis 41 mg/L = 41 ppm = 0.0041TPH

Sample 7

Type Leachate (250 ml) Mix Ratio 2:1 (residue: râpe meal) Mix by Volume 3.5:1 (residue: râpe meal) Mix by Weight Description A mixture of 300 ml (252g) of residue and 150 ml (72g) of râpe meal was placedinto a leach tray. The mixture received the équivalent of 40 mm of précipitation to simulate 8 rainfall events of equal magnitude. A 250 ml sample of the leachate was collected and analyzed. Objective To détermine the concentration of total petroleum hydrocarbons in leachate generated from residue treated with râpe meal by 40 mm Analysis 39 mg/L = 39 ppm = 0.0039 TPH 5 Sample 8

Type Filtrate (250 ml) Mix Ratio 2.0:1 (residue: râpe meal) Mix by Volume 3.5:1 (residue: râpe meal) Mix by Weight 11

Description To produce a 250 ml sample of fîltrate, 300 ml (252g) of residue was combined with 150 ml (72g) of râpe meal and placed into a sealed container. To the container was added 1.6 L of water to simulate the équivalent of 40 mm of précipitation. The container was sealed and forcefully agitated for approximately 2 minutes. While the solids remained in suspension, the mixture was poured into a fine screened funnel and allowed to filter for 4 hours. Objective To détermine the total volume of petroleum hydrocarbons that are dissolved and "washed" ffom a mixture as a resuit of normal hydrologie and gravitational forces acting upon the mixture. Analysis 36 mg/L = 36 ppm = 0.0036 TPH

Sample 9

Type Fîltrate (250 ml) Mix Ratio No Treatment Description A 500 ml (420g) sample of pure râpe meal was placed into fine screened funnel. A fîltrate was produced by pouring 1.6 L of water (équivalent to 40 mm of rain) over the râpe meal. The râpe méat was left to filter for approximately 4 hours. A 250 ml sample of the fîltrate was collected and analyzed. Objective To détermine the concentration of organic (as opposed to petroleum)hydrocarbons leachable from râpe meal under normal gravitation and hydrologie conditions. Analysis <4 mg/L = <4 ppm = <0.0004 TPH

The following table summarizes the above results:

Sample Description Results TPH (%) 1 Raw hog fuel/residue solids (no treatment) 86,6000 mg/kg 8.66 2 Raw hog fuel/residue leachate (4 wettings) 6 mg/L 0.0006 3 4:1 Leached solids (4 wettings) 40,300 mg/kg 4.03 4 4:1 Leachate <4 mg/L <0.0004 12 117 4 4 (4 wettings) 5 4:1 Filtrate <4 mg/L <0.0004 6 4:1 Agitate/filtrate 41 mg/L 0.0041 7 2:1 Leachate (8 wettings) 39 mg/L 0.0039 8 2:1 Agitate/filtrate 36 mg/L 0.0036 9 Râpe meal filtrate <4 mg/L <0.0004

Discussion

The objective of the above analytical testing was to use the presence or absence ofdétectable hydrocarbons in liquids and solids following leaching or filtration, to indicate howeffectively râpe meal (canola meal) and cuttings can immobilize hydrocarbons. In similartenus, the hydrocarbon concentration of leachates and filtrâtes is inversely proportional to theamount of hydrocarbons immobilized. As expected, the greatest concentration ofhydrocarbons (8.7%) occurred in the sample of raw (untreated) residue. This value issomewhat conservative compared to average retort résulte of 14%. The différence may becaused by the dilution resulting from varying amounts of cellulose among the samples ascontributed by the hog fuel constituent.

Mix Ratios

Despite the fact that raany different mix ratios were initially tested with varyingdegrees of success, favourable results were obtained when residue was treated with râpe mealat a ratio of 4 to 1 by volume or 7 to 1 by weight, thus becoming the target mix ratio forfurther analytical testing. The results from the mixing ratio of 2 parts residue to 1 part râpemeal by volume (or 3.5 to 1 by weight), were also tested to provide a reference forcomparison as well as an indication of whether “more is better” in tenus of using râpe mealas an absorbency treatment for petroleum hydrocarbons. Comparison of results from Sample5 and 8 indicate that seemingly less râpe meal is better than more in that the TPH of Sample 5filtrate was considerably less than that of Sample 8. However, a différence in theconcentration of hydrocarbons and amount of hog fuel in the two samples prior to mixingmay also hâve contributed to the différence. Regardless, the différence is well belowimposed limits (lOOOppm or 0.1%) and is therefore negligible. 13

Duration ΐ 1 7 4 4

In most cases, sampling occurred after the équivalent of only 4 and 8 précipitationevents of maximum intensity. The leachate produced during this seemingly short time framewas expected to reflect a biased concentration of hydrocarbons in solution as a conséquenceof hydrocarbon "washing". The expectation is that, initially, a higher than normalconcentration of hydrocarbons will occur in leachates as excess or poorly absorbedhydrocarbons are "washed" or released from mixtures. As a resuit, ail values can beconsidered as maximums.

Limitation of TPH Testing

Although, TPH testing is widely used as an accurate analysis of the presence ofpetroleum hydrocarbons, one limitations does exist. The TPH or MOG (mineral/oil/grease)test is non-selective. It will not differentiate between the different types of petroleumhydrocarbons such as the lighter aromatics (hydrocarbon rings) and the heavier aliphatics(hydrocarbon chains). However, as the présent invention is concemed with theimmobilization of ail petroleum hydrocarbons présent in drilling residue, the TPH testanalysis is suffîcient for the purposes of illustration. 2) Biodégradation Tests

The following tests were conducted to assess the effect of various additives to thetreatment mix on hydrocarbon biodégradation for on-site drilling waste treatment anddisposai. The tested additives included: 1. Re-Activated Sludge (RAS) obtained from the City of Calgary sewagetreatment plant intended to provide an initial inoculum of bacteria, potentially withhydrocarbon-degrading ability. 2. Biocat 4000 - an organic and inorganic liquid nutrient source intended toprovide a complété nutrient source to support microbial growth and hydrocarbonbiodégradation activity. 3. Percarbonate (OX) - a solid oxygen release compound intended to providemore oxygen for faster biodégradation rates.

The test was run for six weeks (41 days) at room température without mixing toassess the effect of the various additives in enhancing the hydrocarbon biodégradation rateover that of a control (no additives). 14 Î1744

Methods

The following samples were tested: a) One 20 L pail of compost mix (oily shale cuttings, wood chips and canola 5 meal).

Note: the pail was sealed and apparently went anaérobie during shipping and storageas it had a strong, pungent odour. b) One 500 ml glass jar containing a slow-release oxygen compound (finewhite powder), four 1 L glass jars of reactivated sludge (RAS). These had gone

10 anaérobie, based on the odour when opened. Ail jars were pooled into a 10L container and aerated ovemight to restore aérobic conditions and ensure viability ofthe RAS. c) One 4L plastic jug of Biocat 4000, containing 70% organic + 30% inorganicnutrient base. 15

To each of four 6L reactors (with removable gasket sealed lids) was added 4L of thetreatment mixture. The different additives tested were as follows:

Test Solutions

Sample Additives 1 240 ml of reverse-osmosis de-ionized water (DRO) (simulating rainfall) 2 200 ml of Recycle Activated Sludge (RAS) (6 vol%); 40 ml of DRO 3 200 ml RAS; 40 ml of Biocat 4000 dilution (2 ml concentrate in 38 ml DRO) 4 200 ml of RAS 40 ml of Biocat 4000 dilution (2 ML concentrate in 38 ml DRO) 40 ml of Percarbonate Oxygen Release Additive (ΟΧ) (1 vol%) 20

Ail 4L test blends were thoroughly mixed by hand in an 8L vessel before being placed intothe 6L reactors. A soil moisture probe indicated that ail mixes were wet, but no free-standingwater was présent. Each test mixture was sampled (200 ml) for initial analysis of:

-pH 25 - Electrical conductivity, EC (dS/m) 15 117 4 4 - Moisture content (wt%) - Total heterotrophic bacteria (THB) by Most Probable Number (MPN) (48 hrMPN/g) - Hydrocarbon-degrading bacteria (HDB) by MPN (14 day MPN/g) 5 - Total Extractable Hydrocarbons (T.E.H. C8-C30, by GC/FID analysis) (mg/kg) - Available Nutrients (N, P, K, S) (mg/kg) - Total Kjeldahl Nitrogen (TKN) (wt%) 10 Ail reactors were incubated at room température, which varied between 19 and 24°C.

The surface of each reactor was exposed to the room light for about 8 hours a day.

Periodically, the gasket lids were placed on the reactors and the rate of oxygen uptakeand carbon dioxide évolution was recorded. Following détermination of the respiration rate,the lids were removed to ensure continued passive aération of the mix. To assess the 15 potential for passive diffusion of air ffom the surface, no further mixing was done. Depth ofeach test mix in the reactors was recorded at the start and end of the test to détermine theextent of compaction following active dégradation.

Results and Discussion 20 The test was run for 41 day s. The analytical results on Day 0 and Day 41 are summarized in the following table:

Parameter Test Day Initial Mix Test 1 Test 2 Test 3 Test 4 PH 0 N/D 7.3 7.8 7.7 9.1 41 7.7 7.8 7.8 9.4 EC 0 N/D N/D N/D N/D N/D 41 4.96 4.83 4.54 8.26 Moisture 0 37.3 40 40 40 36 41 19 24 21.7 21.8 16 117 4 4

Mix Temp (°C) 0 5 8 13 26 41 N/A N/D 29 25.5 24.5 23 23.5 N/D 29 26 24.5 23.5 23.5 N/D 31 27 26 24 23.5 N/D 30 26 25.5 23,8 23.5 Mix height (cm) 0 41 N/A 12.5 11.5 13 11 12 11 13 11.3 Heterotrophic bacteria 0 41 N/D 1.3xl09 2.1xlO10 >10” >10" N/D >10” N/D 2.3xl08 HC-degrading bacteria 0 41 N/D 7.9x102 1.3x104 1.3xl03 4.9x102 N/D 2.8xl04 N/D 2.3xl02 Total Kjeldahl nitrogen 0 41 0.97 1 0.87 1.05 0.88 1.03 0.89 1 0.85 Ammonia - N 0 N/D N/D N/D N/D N/D 41 29.9 1700 1780 1350 Nitrate-nitrogen 0 41 N/D 4.4 1 5 7.4 5.1 1.2 4.4 1.3 Phosphate - P 0 41 N/D 56 78 81 101 80 115 110 155 Sulphate - S 0 41 N/D 378 564 377 520 368 508 754 1400 Potassium 0 41 N/D 955 1450 1550 1860 1320 1600 1220 1590 Total extractable HC 0 114561 N/D N/D N/D N/D 41 N/D 40280 59155 69571 85437 % T.E.H réduction 41 N/A 65 48 39 25 N/D - not determined; N/A - not applicable

The initial mix contained about 114,600 mg/kg total extractable hydrocarbons. This is shown in Figure 1, which illustrâtes the mass fractions of the total extractable5 hydrocarbons (T.E.H.) from the initial mix at test Day 0 compared to the residual T.E.H. from each test after Day 41. Only about 3% of the T.E.H. was C30+ material. 17 11 7 4 4

Test 1 - Control

The control was the same as the initial mix, but received sufficient water to supportgood bioactivity. Overall, the control appears to hâve yielded the best hydrocarbondégradation results.

Composting activity was évident by the increase in température within the test mix onDay 5 through Day 26. The test mix retained 92% of its initial height after 41 days.

There was a higher than expected initial bacterial population (1.3 x 109 MPN/g) in thecontrol, suggesting that a natural bacterial inoculum may hâve been provided with the mixnitrogen source, wood shavings, and/or the drill cuttings. The initial hydrocarbon-degradingbacteria count was much lower (7.9 x 102) indicating that the population had not yet adaptedto the hydrocarbon content. It should also be noted here that a significant development ofwhite-rot fungi was not observed in any test mix, contrary to reports from fîeld observationsduring composting of the mix not containing any additives.

The control mix provided the greatest extent of hydrocarbon biodégradation (85%,based on a single composite sample analysis). Figures 2 and 3 illustrate the results of theGC/FID analysis of the residual hydrocarbons in the C8-C3O range compared to the initialhydrocarbons présent at Day 0. A négative change in the mass fraction of the residualhydrocarbons indicates that there is less of that fraction than in the initial hydrocarbon. Theloss of both light (C8-C11) and heavy (C21-C3O+) hydrocarbons shows that biodégradation isoccurring. Some of the C8-C11 loss may be due to volatilization during préparation of theadditive containing test mixes. The apparent increase in the C12-C20 range hydrocarbonsresults from the mass fractions needed for total unity (1). Some of the heavy fractions mayhâve been degraded to smaller hydrocarbons in the C12-C20 range.

Nutrient analysis showed that no nutrients were limiting foliowing the 41-day test.Moisture content had dropped to about one-half of the initial, despite periodic misting of thesurface of the test mix. At the end of the test, the moisture content in the top 3/4 of the testmix was only 9.1 wt%, whereas the bottom 1/4 was 35.4 wt%.

The low moisture présent at the end of the test would explain the drop-off ofrespiration activity as shown in Figures 4 and 5 after Day 13. Since mixing was not allowedduring the test, it was diffîcult to ensure adéquate moisture was maintained throughout thetest mix. A definite layering of moisture was observed in ail tests, with the bottom being wetand the top being dry. 18 11 744

Continuée! watering would hâve allowed free water to collect on the bottom of thereactor, which would hâve lead to anaérobie conditions. In future tests, reactors with leachatedrains should be used so that more water can be added throughout the test.

Test 2 - RAS Onlv

Composting activity was évident by the increase in température within the test mix onDay 5 through Day 26. The test mix retained 87% of its initial height after 41 days.

The addition of the recycled activated sludge (RAS) increased the initial bacterialpopulation as expected (>1011 MPN/g), although the effect was not as pronounced because ofthe high initial population in the initial mix. The initial hydrocarbon-degrading bacteriacount was still low (1.3 x 103) indicating that there was not a high proportion of hydrocarbon-degrading bacteria in the RAS.

The sample with only the RAS additive provided the second greatest extent ofhydrocarbon biodégradation (48%, based on a single composite sample analysis). Figure 2shows the results of the GC/FID analysis of the residual hydrocarbons in the C8-C30 rangecompared to the initial hydrocarbons présent at Day 0. Similar to the Test 1 results, the lossof both light (C8-C11) and heavy (C21-C30+) hydrocarbon, together with positive respirationdata, shows that biodégradation is occumng. Some of the C8-C11 loss may be due tovolatilization during préparation of the test mixes.

Nutrient analysis showed that no nutrients were limiting foliowing the 41-day test.Unlike the Control test, the RAS additive caused a high ammonia content to develop in thetest mix by Day 41 (1700 mg/kg NH4-N). This could be a resuit of the dégradation of thesome RAS bio-solids, releasing ammonia through de-amination of proteins. This level ofammonia may be toxic to some bacteria. The heterotrophic bacterial count remained high(>10H MPN/g) indicating that signifîcant bacteria death had not occurred. The hydrocarbon-degrading bacteria population had not increased, or had not remained viable by Day 41.

Moisture content had dropped to about one-half of the initial, despite periodic mistingof the surface of the test mix. At the end of the test, the moisture content in the top 3/4 of thetest mix was only 9.4 wt%, whereas the bottom 1/4 was 39 wt%.

The low moisture présent at the end of the test would explain the drop off of respiration activity as shown in Figures 4 and 5 after Day 13. This may also explain the low hydrocarbon-degrading bacteria count. 19 117 4 4

Test 3 - RAS + Biocat 4000

Composting activity was évident by the increase in température within the test mix onDay 5 through Day 26. Test 3 showed the highest sustained température increase, indicatingthe greatest bioactivity. The test mix retained 92% of its initial height after 41 days.

Although not analyzed directly, the addition of the re-activated sludge (RAS) shouldhâve increased the initial heterotrophic bacterial population similar to Test 2. The initialhydrocarbon-degrading bacteria count would also be similar to Test 2 as the Biocat 4000 doesnot contain live bacteria (not confirmed in this test).

The RAS+Biocat 4000 additive provided the third greatest extent of hydrocarbonbiodégradation (39%, based on a single composite sample analysis). Figure 2 shows theresults of the GC/FID analysis of the residual hydrocarbons in the C8-C30 range compared tothe initial hydrocarbons présent at Day 0. A greater loss of light (C8-C14) and less loss ofheavy (C22 only) hydrocarbons was observed. The change in hydrocarbon ffom the initialshows that biodégradation is occurring, but to a lesser extent then in Tests 1 and 2. Asbefore, some of the C8-C11 loss may be due to volatilization during préparation of the testmixes. Biocat 4000 may also hâve introduced some vegetation-based organics that show upin GC/FID analysis as hydrocarbons in the C15-C30+ range, although this remains to bedetermined.

Nutrient analysis showed that no nutrients were limiting foliowing the 41-day test.Similar to Test 2, the RAS additive caused a high ammonia content to develop in the test mixby Day 41 (1780 mg/kg NH4-N). The heterotrophic bacterial count remained high (>1011MPN/g) indicating that significant bacteria death had not occurred. The hydrocarbon-degrading bacteria population had increased compared to Test 2, but was still low on Day 41.

Moisture content had dropped to about one-half of the initial, despite periodic mistingof the surface of the test mix. At the end of the test, the moisture content in the top 3/4 of thetest mix was only 9.6 wt%, whereas the bottom 1/4 was 38 wt%.

Test 3 had the overall highest rate of respiration, which agréés with the highestobserved température in this test mix. The low moisture présent at the end of the test wouldexplain the drop off of respiration activity as shown in Figures 4 and 6 after Day 13. Thismay also explain the low hydrocarbon-degrading bacteria count.

Test 3 showed the highest apparent bioactivity, but only the third highest réduction inresidual T.E.H. This may hâve resulted because the RAS additive introduced a significantpopulation of bacteria more adapted to degrading the wood shavings (cellulolytic activity) 20 117 4 4 and organic nitrogen source in the initial mix than the hydrocarbons and was stimulated bythe Biocat 4000.

Test 4 - RAS + Biocat 4000 + Percarbonate oxygen release, compound (OX)

Composting activity was évident by the increase in température within the test mix onDay 5 through Day 26. The test mix retained 87% of its initial height after 41 days.

The most noticeable différence in this test was the high pH of 9.4 that developed as aresuit of the percarbonate addition. The initial pH was raised from about 7.7 to 9.1 by theaddition of 1 vol% percarbonate. This high pH would hâve an inhibitory effect on thebacterial activity.

Although not analyzed directly, the addition of the recycled activated sludge (RAS)should hâve increased the initial heterotrophic bacterial population similar to Tests 2 and 3.The initial hydrocarbon-degrading bacteria count would also be similar to Tests 2 and 3.

The RAS+Biocat+OX additive provided the lowest extent of hydrocarbonbiodégradation (25%, based on a single composite sample analysis). Figure 2 shows theresults of the GC/FID analysis of the residual hydrocarbons in the C8-C30 range compared tothe initial hydrocarbons présent at Day 0. Similar to Test 3, a greater loss of light (C8-C14)and less loss of heavy (C22 only) hydrocarbons was observed. The change in hydrocarbonfrom the initial shows that biodégradation is occurring, but to a lesser extent than in Tests 1and 2. Some of the C8-C11 loss may be due to volatilization during préparation of the testmixes. Biocat 4000 may also hâve introduced some vegetation-based organics that show upin GC/FID analysis as hydrocarbons in the C15-C30+ range, although this remains to bedetermined.

Nutrient analysis showed that no nutrients were limiting following the 41 day test.Similar to Tests 2 and 3, the RAS additive caused a high ammonia content to develop in thetest mix by Day 41 (1350 mg/kg NH4-N). The heterotrophic bacterial count was lower thanthe other tests (2.3 x 106 MPN/g) indicating that significant bacteria death had occurred. Thehydrocarbon-degrading bacteria population was also very low on Day 41. The lowerbacterial populations are most likely a resuit of the high pH in this test mix, compared to theother tests.

Moisture content had dropped to about one-half of the initial, despite periodic mistingof the surface of the test mix. At the end of the test, the moisture content in the 3/4 of the testmix was only 10.3 wt%, whereas the bottom 1/4 was 37 wt%. 21 117 4 4

Test 4 had the lowest overall rate of respiration, which agréés with the lowestobserved température in this test mix. The low moisture présent at the end of the test wouldexplain the drop off of respiration activity as shown in Figures 4 and 5 aller Day 13.

Conclusions • The recycled activated sludge (RAS) did not provide an adapted population ofhydrocarbon-degrading bacteria and may hâve introduced a competing cellulolytic activity,although the latter possibility requires further confirmation, • RAS biosolids dégradation causes a very high ammonia-nitrogen content in excess of1300 mg/kg, which could be potentially toxic to the hydrocarbon-degrading bacteria. • Biocat 4000 stimulated activity in Test 3, but did not provide enhanced hydrocarbon-degradation results. • Percarbonate solid oxygen release compound caused an initial high pH of 9,1, whichresulted in lower microbial activity as shown by respiration and température results. • The treatment mix (control) appears to be fairly well balanced and supported goodmicrobial activity and rapid hydrocarbon dégradation without additives such as bacteria,nutrients, or oxygen. Adéquate total nitrogen (0.87%) and phosphate (78 mg/4) was stillprésent after 41 days treatment. • After 41 days the height of the test mixes had ail been 87-92% maintained, indicatingthat the treatment mix does not readily compact during composting, thereby maintaining itsporosity and passive aération potential. • The treatment mix tends to dry out with time, as water drains downward. The mixdoes receive added water readily (i.e., is not hydrophobie despite the high initial hydrocarboncontent). • Based on the observations made during this test, moisture content maintenance will bea limiting factor in maintaining rapid hydrocarbon biodégradation activity. 22 11744 • Before quoting the findings from this test, the initial and final T.E.H. analysis shouldbe repeated to obtain a measure of confidence in the data. This is required because at thelevel where hydrocarbons are analyzed, a certain amount of variability is inhérent even in amixture like that described above. 3) Bioremediation Field Plots

Tests were conducted to détermine the efficacy of using a combination of canola mealand dry wood shavings to contain and microbially décomposé oily drilling residuals in ahomogenous mix. The main objective was to collect analytical data from laboratory and fieldapplications to characterize the on-site treatment (mixing) of the présent invention and theland spreading process. 30 field plots were established at the University of Alberta Ellerslie Field ResearchFacility located south of Edmonton, Alberta Canada. Typical drilling location conditionswere simulated by removing the organic topsoils from each 3m x 5m plot.

Results

Figures 6 and 7 illustrate the results of the above field tests.

Preliminary field results for a period of 107 days indicated that the total réduction inhydrocarbons under field conditions is as high as 57% for invert based containment mixesand 37% for sait water free based containment mixes with minimal leaching limited to thetop2.5 cm of the underlying soil.

As mentioned previously, although the présent invention has been described inspécifie relation to the use of canola (or râpe) meal as the protein source, various othersources are also possible. Some examples are as follows: cottonseed meal, soybean meal,alfalfa meal, bone meal, blood meal, feather meal, kelp meal, peanut meal, borage meal, cornmeal, coconut meal, sesame seed meal, safflower meal, sunflower meal, hemp meal, andsugar beat meal. It will be understood by persons skilled in the art that any other similarprotein source can be used in the présent invention.

Although the invention has been described with reference to certain spécifieembodiments, various modifications thereof will be apparent to those skilled in the artwithout departing from the spirit and scope of the invention as outlined in the daimsappended hereto. 23

Claims (12)

11744 AMENDED CLAIMS

1. A composition for treating solid material contaminated with hydrocarbons whereinthe hydrocarbon contaminant is interspersed throughout the material, said compositionincluding a protein component, said protein component comprising a protein meal having amicrobial culture capable of metabolizing said hydrocarbon contaminant, and a bulkingcomponent.

2. The composition of claim 1 wherein said protein meal is derived from canola, soy,cotton, corn, or peanut material or from other protein based material.

3. The composition of claim 1 wherein said bulking agent is derived from organicmaterial or from inorganic équivalents.

4. The composition of claim 3 wherein said bulking agent is chosen from woodshavings, peat moss, straw or any combination thereof.

5. The composition of claim 1 wherein said protein component is capable of absorbingor adsorbing said hydrocarbon contaminants.

6. A method for treating hydrocarbon contaminated material with the treatmentcomposition of claim 1 comprising the steps of: 1) contacting said contaminated material with the treatment composition toimmobilize and prevent leaching of said contaminant; and, 2) biodegrading said hydrocarbon contaminant with the microbial culture.

7. A method for treating solid material contaminated with hydrocarbons, wherein thehydrocarbon contaminant is interspersed throughout the material, said method comprisingtreating said contaminated material with a treatment composition comprising a proteincomponent, said protein component comprising a protein meal having a microbial culturecapable of metabolizing said hydrocarbon contaminant, and a bulking agent, the methodcomprising the steps of: 1) contacting said material with said treatment composition to immobilize thehydrocarbon contaminant; and, 24- T1 7 4 4 2) biodegrading said contaminant with said microbial culture.

8. The process of claim 7 wherein said contacting phase comprises mixing or blendingthe contaminated material with the treatment composition

9. The method of claim 7 wherein said bulking agent is chosen ffom wood shavings, 5 peat moss, straw or any combination thereof.

10. The method of claim 7 wherein said material comprises drill cuttings or soils.

11. The composition of claim 1 wherein said microbial culture of said protein meal isindigenous.

12. The method of claim 7 wherein said microbial culture of said protein meal isindigenous. 25