This article was downloaded by: [North Dakota State University]On: 26 October 2014, At: 19:34Publisher: Taylor & FrancisInforma Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House,37-41 Mortimer Street, London W1T 3JH, UK

Soil and Sediment Contamination: An InternationalJournalPublication details, including instructions for authors and subscription information:http://www.tandfonline.com/loi/bssc20

Compost Soil Piles for Treatment of Oil-ContaminatedSoilR. Al-Daher a , N. Al-Awadhi a , A. Yateem a , M. T. Balba a & A. ElNawawy ba Kuwait Institute for Scientific Research, P.O. Box 24885, 13109 Safat, Kuwaitb Soil & Water Research Institute, Agricultural Research Center, Giza, EgyptPublished online: 24 Jun 2010.

To cite this article: R. Al-Daher , N. Al-Awadhi , A. Yateem , M. T. Balba & A. ElNawawy (2001) Compost Soil Piles forTreatment of Oil-Contaminated Soil, Soil and Sediment Contamination: An International Journal, 10:2, 197-209

To link to this article: http://dx.doi.org/10.1080/20015891109211

PLEASE SCROLL DOWN FOR ARTICLE

Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) containedin the publications on our platform. However, Taylor & Francis, our agents, and our licensors make norepresentations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of theContent. Any opinions and views expressed in this publication are the opinions and views of the authors, andare not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon andshould be independently verified with primary sources of information. Taylor and Francis shall not be liable forany losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoeveror howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use ofthe Content.

This article may be used for research, teaching, and private study purposes. Any substantial or systematicreproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in anyform to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://www.tandfonline.com/page/terms-and-conditions

197

Soil and Sediment Contamination, 10(2):197-209 (2001)

1532-0383/00/$.50© 2001 by AEHS

Compost Soil Piles for Treatment of Oil-Contaminated Soil

R. Al-Daher, N. Al-Awadhi, A.Yateem, and M.T. Balba

Kuwait Institute for Scientific Research, P.O.Box 24885, 13109 Safat, Kuwait

A. ElNawawy

Soil & Water Research Institute, AgriculturalResearch Center, Giza, Egypt

A number of diverse technological optionsare being considered for the remediation ofsoil contaminated with weathered crude oilin Kuwait. The bioremediation techniqueinvolving the use of composting soil pileswas selected from among the most appro-priate methods and evaluated on a pilotscale. The field test was conducted fromNovember 1992 to September 1993 at theBurgan oil field. Soil piles were constructedfrom the contaminated soil after amend-ment with necessary soil additives. Thepiles were subjected to regular irrigationand turning, and a monitoring program wascarried out, including monthly soil samplecollection from each pile for the measure-ment of petroleum hydrocarbon PAHs, soilmicrobial counts, mineral and metal con-centrations. The results obtained showedthat the composting soil pile treatment re-sulted in the reduction of up to 59% totalextractable matter of oil contaminationwithin 8 months. This article describes thetechnology used and summarizes the re-sults obtained.

340278.pgs 3/15/01, 5:44 PM197

Dow

nloa

ded

by [

Nor

th D

akot

a St

ate

Uni

vers

ity]

at 1

9:34

26

Oct

ober

201

4

198

INTRODUCTION

uring the Iraqi invasion and occupation of Kuwait, vast amounts of desertsoil were severely impacted by the release of large volumes of crude oil

and the aerial deposition of partially combusted oil particles and associatednoncombusted products from the oil fires. Oil accumulated in shallow depressionsto form approximately 70 oil lakes. The area covered by oil lakes has beenestimated to be approximately 50 km2 distributed in the southern and northern oilfields, and the volume of oil contained in the oil lakes is estimated to be 9 millionm3. It has also been estimated that the depth of oil penetration into the soil belowthe oil lakes is about 0.7 m. In a few cases, penetration exceeding more than 2.5m was reported by Al-Awadhi et al. (1995). The volume of heavily oil-contami-nated soil that needs to be treated in Kuwait is estimated to be more than 20 millionm3. In addition, the surface area subjected to aerial fallout covers several hundredsquare kilometers (Al-Awadhi et al., 1993). The oil content of the heavily contami-nated soil must be reduced substantially to restore the potential of Kuwait’s landfor vegetation and animal production, and to guard against long-term adversehazards to human health.

Bioremediation technologies exploit the natural ability of microorganisms todegrade organic chemical contamination in soil and groundwater. The goal ofactive bioremediation of soil is to utilize microbial systems to efficiently remediatecontaminated areas. In all cases, the desired end point is complete biodegradationof the toxic substances into carbon dioxide, water, and cell biomass.

Compost soil piles are effective for above-ground application to high-strengthwaste streams requiring more controlled environments. Composting can be initi-ated by mixing biodegradable organic matter with bulking agents (and possiblywith other materials). In conventional composting systems, bulking agents areadded to enhance the porosity of the mixture to be composted, but they may alsoprovide additional carbon, or food for the microorganisms. Materials of relativelylow organic content may be composted through the addition of other sources highin organic carbon such as municipal sludge or manure. In such cases, the addedorganic material is degraded, which help to maintain the necessary microbialpopulation in the mixture.

Microorganisms, chiefly bacteria, are capable of mediating the biodegradationof a wide variety of compounds, including the aliphatic and aromatics comprisingpetroleum fuels (Singer and Finnerty, 1984; Cerniglia, 1984), polyaromatic hydro-carbons (PAHs) (Cerniglia, 1984), chlorinated aliphatic hydrocarbons (Fogel etal., 1986), and even chlorinated aromatics such as PCP (Vala and Sakinoja-Sanonen, 1986; Haggblom, 1990).

Most simple petroleum hydrocarbons, phenols, and lower PAHs are known tobe degraded rapidly under aerobic conditions (Rogers et al., 1993; Bradford andKrishnamoorthy, 1991), while higher-molecular-weight PAHs of five or morerings resist extensive bacterial degradation in soil. The recalcitrant behavior of

D

340278.pgs 3/15/01, 5:44 PM198

Dow

nloa

ded

by [

Nor

th D

akot

a St

ate

Uni

vers

ity]

at 1

9:34

26

Oct

ober

201

4

199

such compounds can be attributed to their limited bioavailability and strongadsorption onto soil particles and organic matter (Field et al., 1992). Microbialattack is dependent on the solubility of PAHs and the adsorption capacity of the soilparticles.

There are a number of different technologies that can be considered for thedirect remediation of oil-polluted soil. Bioremediation may be the most cost-effective treatment for effective treatment for cleaning of the soil (Al-Awadhi etal., 1996). The bioremediation technique assessed in this study is the windrow soilpile system. The main objective of this study was to assess the effectiveness of thistreatment method for both lightly and heavily oil-contaminated soil under Kuwaitconditions and the feasibility for large-scale application.

MATERIAL AND METHODS

Experimental Design

This bioremediation pilot study was conducted at the Burgan oil field site (approx.70 miles north of Kuwait City). The investigations started in November 1992 andconcluded in September 1993 were designed to allow for the examination of theeffect of fertilization, irrigation and other different supplements on the degradationrate of oil contamination in lightly contaminated soil (<0.3% oil) and heavilycontaminated soil (3 to 10% oil). Soil piles (20 m3 each) were prepared (each pile3 m width × 10 m length × 1.5 m height) from heavily and lightly contaminatedsoil with different supplements, such as inorganic fertilizer (NPK 15:15:15), togive a ratio of C:N as 50:1; wood chips (100 l/m3); dried sewage sludge (40 kg/m3

soil); mature compost (12 kg/m3 soil); and hydrocarbon-utilizing bacteria. A mixedmicrobial culture (not identified) was enriched from oil-contaminated soil col-lected from the Burgan oil field. The mixed culture was propagated in the labora-tory using B. Braun Biostat(R) fermenter and hexadecane (1 g/l) as the sole sourceof carbon and energy. The culture density was in the range of 107 CFU/ml.Approximately 20 l of the culture broth was added to each soil pile (20 m3).

The soil piles were subjected to irrigation manually by hose using freshwater tomaintain the soil moisture within the range between 5 to 10%. Fresh water addedonce a week during winter season (10 gallons/m3 of soil) and twice a week duringthe summer period from May to September), and to turning and mixing using afront-loader once every month.

Sampling

Representative soil samples were collected monthly from the soil piles for analysisand bioremediation monitoring. One composite sample from each soil pile was

340278.pgs 3/15/01, 5:44 PM199

Dow

nloa

ded

by [

Nor

th D

akot

a St

ate

Uni

vers

ity]

at 1

9:34

26

Oct

ober

201

4

200

used for this purpose. The composite sample was prepared from 30 randomlycollected samples, which were combined and mixed thoroughly before analyses.

Analytical Methods

Total extractable matter (TEM) was determined by extracting the soil, usingdichloromethane solvent and a soxhlet apparatus. The solvent was then evaporated,and the mass of the extracted material was determined by gravimetric measurement(U.S. EPA, 1986).

A gas chromatograph fitted with flame ionization detector (GC-FID) was usedto characterize the residual alkane fraction at the beginning of the treatment and atthe end of 10 months. For this purpose, a fraction of the extractable matter wasredissolved in dichloromethane, cleaned up on an alumina column, and analyzedby GC-FID (Walters et al., 1989). The aliphatic hydrocarbons (i.e., alkanes) wereanalyzed by GC-FID (Hewlett Packard Model 5890, Series 11); to the soil sample,10 to 15 g of Na2S04 was added in a round-bottom flask, and then the flask wasshaken. After drying, 6 to 70 ml of 1,1,2-trichloro 1,2,2-fluoroethane was added,and the flask was shaken for 2 h in an orbital shaker. The extract was filtered andthe residue dissolved in 2 ml of 1,2,2-fluoroethane. An external standard hydrocar-bon mixture of 20 ng/µl of each hydrocarbon (C10 to C32) was used for quantitativedetermination. The soil extracts were also analyzed, at the end of the treatment, bygas chromatography with a mass spectrophotometer (GC-MS) for the identifica-tion and quantification of individual PAHs in the treated soil. The following PAHswere identified and measured: naphthalene, acenaphthylene, acenaphthene, fluo-rene, phenanthrene, anthracene, fluoranthene, pyrene, benzo(a)anthracene, chrysene,benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, dibenzoanthracene,indenopyrene, and benzo(g,h,i)perylene.

Respiration Rate

CO2 production of the microbial population in the soil was examined by respiro-metric analysis, using a biometric flask in which soil representative samples wereincubated for a period of 24 h at 30°C. The absorbed C02 in the sodium hydroxidesolutes determined by volumetric titration according to Bartha and Pramer (1965).

Bacterial Counts

The total bacterial counts was assayed in the oil-contaminated soil and expressedas total colony-forming units (CFU) per gram of soil according to Lorch et al.(1995). The assay was carried out for the determination of mesophilic microorgan-

340278.pgs 3/15/01, 5:44 PM200

Dow

nloa

ded

by [

Nor

th D

akot

a St

ate

Uni

vers

ity]

at 1

9:34

26

Oct

ober

201

4

201

isms (incubated at 30°C for 2 days). The drop plate technique was applied usingnutrient agar and basal medium. Hexadecane was used as the sole carbon source.

A drop (0.01 ml) of the aquous soil suspensions (1 g/l00 ml) sample wasadded to the solidified media in the agar plates. For hydrocarbon-degradingbacteria basal media supplemented with hexadecane was used in the prepara-tion of agar plates. Three replicates were made and plates were incubated at30°C for 24 h before total bacterial counts were made for nutrient agar mediaand for 72 h before hydrocarbon-degrading bacterial counts were made formineral basal media.

Minerals

Minerals in soil samples were analyzed by inductivity-coupled argon plasmaoptical emission spectrometry (ICAP-OES). Five oven-dried, sieved samples wereweighed into glass beakers, and 40 ml of ultrapure nitric acid was added. Theywere heated to near dryness, HClO4 was added, and then they were heated forcomplete extraction. The solution was analyzed by ICAP.

Data Interpretation

The treatment continued for a period of 10 months, during which the oil concen-tration in the soil vs. time was calculated and used to determine the rates of oildegradation in terms of percentage of reduction.

RESULTS AND DISCUSSION

Oil biodegradation in soil is typically affected by several factors, for example,oxygen and nutrient availability, soil moisture content, pH and salinity of the soil,soil structure and organic content, temperature, solubility of the pollutants, concen-tration of toxic compounds, and concentration of contaminant-degrading microor-ganisms in the soil. The general characteristics of Kuwait’s soil are suitable forbioremediation (i.e., calcareous sand) with a silt concentration of less than 6%, pHof 7.5 to 8.0, electrical conductivity of 0.6, and organic matter of less than 0.02%.The soil contains typically 105 to 106 bacteria and 101 to 102 fungi per gram, andits water-holding capacity is about 12 to 15%. Thus, for the optimization ofbioremediation of oil contamination, the soil should be provided with a suitablesource for the major nutrients (NPK), moisture, and oxygen (through periodicmixing). If these factors are adjusted, then the rate of oil biodegradation will bepredominantly dependent on the type and concentration of oil in the soil andambient temperature.

340278.pgs 3/15/01, 5:44 PM201

Dow

nloa

ded

by [

Nor

th D

akot

a St

ate

Uni

vers

ity]

at 1

9:34

26

Oct

ober

201

4

202

Despite the variance of the initial hydrocarbon concentrations, especially duringthe initial period of treatment, a gradual and consistent decrease in the TEMconcentration with time in all piles was observed. The maximum degradation inTEM in the lightly and heavily contaminated soil observed after 8 months were 52and 59%, respectively (Table 1). However, no significant influence of compost orsewage sludge addition on the biodegradation rate was identified. The addition ofa hydrocarbon-utilizing bacterial culture, 3 months after the piles were constructed,had no effect on hydrocarbon degradation. This may be due to the presence of

TABLE 1Rate of Oil Biodegradation in Soil Piles

340278.pgs 3/15/01, 5:44 PM202

Dow

nloa

ded

by [

Nor

th D

akot

a St

ate

Uni

vers

ity]

at 1

9:34

26

Oct

ober

201

4

203

hydrocarbon-degrading indigenous microorganisms in the soil, the limited amountof microbial inoculum used, and/or the competition of the added culture with theindigenous soil microorganisms (Salkinoja-Saonen, 1990; Leahy and Colwell,1990).

Microbiological analysis of soil samples during the bioremediation treatmentshowed a healthy microbial population and did not indicate any toxicity.

The counts of heterotrophic bacteria determined as colony forming units(CFU) remained in the range of 106 to 107 CFU/g throughout the entire durationof treatment. The numbers were relatively high for aerobic heterotrophic bacte-ria, that is, approximately 107 CFU/g soil. The hydrocarbon-degrading bacteriawere also in the range of 107 CFU/g. However, the numbers of hydrocarbon-degrading bacteria decreased to their background level following the peak ofmaximum oil degradation (February to April 1993). This decrease was possiblydue to the diminished concentration of biodegradable hydrocarbon substrates(Figure 1). The weather conditions and decreasing moisture content could pos-sibly cause the decrease in the hydrocarbon-degrading bacteria population also.

During the soil bioremediation, CO2 production was monitored to assess micro-bial activity. The results are presented in Figure 2. There is a direct correlationbetween the maximum degradation phase and respiration. In the first 3 months,there was an increase in the production of CO2 due to the enhanced microbialactivities. Respiration rates decreased at the end of remediation due to the recal-citrant nature of the residual hydrocarbons left in the soil. Bacterial numbers werehigh during the period with maximum respiration rates, and a decline in bacterialnumbers was accompanied by decreasing respiration rates. As can be seen fromFigure 3, there is a clear correlation between respiration and microbial counts.

The average PAHs content in the soil piles were measured toward the endof the treatment, and their concentration in heavily contaminated soil piles wasreduced from an initial value of 26.50 mg/kg to 3.45 mg/kg, which is equiva-lent to a reduction of approximately 87% within 8 months (Figure 4). Thelightly contaminated soil piles contained low concentration of PAH’s around11 mg/kg and was reduced after the treatment to 5 mg/kg (approx. 54.5%).

The initial measurements of minerals and metals at the end of the treatment(Table 2) in the composting soil piles showed increased concentrations, particu-larly for sulfur, barium, and calcium. The sulfur and barium content measured inthe piles increased significantly by the end of remediation; this may be due to theoil degradation and/or soil supplements. The concentration of sodium and chloridedecreased during the remediation process and may have been caused by leaching.No significant changes were observed in the concentration of other metals.

CONCLUSION

The results of this study demonstrated the usability of compost soil pile treatmentsystem for the remediation of oil-contaminated soil under Kuwait conditions. It

340278.pgs 3/15/01, 5:44 PM203

Dow

nloa

ded

by [

Nor

th D

akot

a St

ate

Uni

vers

ity]

at 1

9:34

26

Oct

ober

201

4

204

FIG

UR

E 1

Het

erot

roph

ic a

nd h

ydro

carb

on-d

egra

ding

bac

teria

dur

ing

rem

edia

tion.

340278.pgs 3/15/01, 5:44 PM204

Dow

nloa

ded

by [

Nor

th D

akot

a St

ate

Uni

vers

ity]

at 1

9:34

26

Oct

ober

201

4

205

FIG

UR

E 2

Res

pira

tion

rate

and

hyd

roca

rbon

con

tent

in t

he s

oil p

iles.

340278.pgs 3/15/01, 5:44 PM205

Dow

nloa

ded

by [

Nor

th D

akot

a St

ate

Uni

vers

ity]

at 1

9:34

26

Oct

ober

201

4

206

FIG

UR

E 3

Rel

atio

nshi

p be

twee

n th

e co

unts

of

hydr

ocar

bon

degr

ader

and

res

pira

tion

rate

dur

ing

rem

edia

tion.

340278.pgs 3/15/01, 5:44 PM206

Dow

nloa

ded

by [

Nor

th D

akot

a St

ate

Uni

vers

ity]

at 1

9:34

26

Oct

ober

201

4

207

FIG

UR

E 4

PA

H’s

con

tent

in a

sel

ecte

d co

mpo

sted

soi

l pile

.

340278.pgs 3/15/01, 5:44 PM207

Dow

nloa

ded

by [

Nor

th D

akot

a St

ate

Uni

vers

ity]

at 1

9:34

26

Oct

ober

201

4

208

TABLE 2Mean Minerals Content during Remediation of the Soil Piles

was possible to stimulate the indigenous microbial population and sustain an activehydrocarbon degrading microbial count by supplementation of inorganic fertilizer,moisture adjustment, and soil mixing for ensuring sufficient aeration. The oilbiodegradation rates were at maximum during autumn, winter, and spring months,but dropped during the hot summer, possibly due to the elevated ambient tempera-ture, rapid evaporation of water, and possible reduction of readily biodegradablepetroleum hydrocarbon compounds. Active oil biodegradation was accompaniedby a high production of carbon dioxide, indicating a complete degradation of oilconstituents to water and carbon dioxide with an optimum respiration rate inMarch.

In general, it can be concluded that soil-composting piles is an effective ap-proach for the remediation of oil-contaminated soil. It was possible to degrade upto 59% of the total extractable matter in heavily contaminated soil during the first8 months. The degradation rate can be significantly enhanced, especially if themoisture content and aeration were optimized.

ACKNOWLEDGMENT

The authors express their sincere appreciation to Dr. Monika Michaelson fromUmweltschutz Nord, Germany, for her technical support and analytical assistance.

340278.pgs 3/15/01, 5:44 PM208

Dow

nloa

ded

by [

Nor

th D

akot

a St

ate

Uni

vers

ity]

at 1

9:34

26

Oct

ober

201

4

209

REFERENCES

Al-Awadhi, N., Williamson, K.J., and Isok, J.D. 1993. Remediation of Kuwait’s oilcontaminated soils. Hydrocarb. Contamin. Soils Ground Water. 3,9–21.Al-Awadhi, N., Balba, M.T., Puskas, K., Al-Daher, R., Tsuji, H., Chino, H., Tsuji, K., Iwabuchi, M.,

and Kumamoto, S. 1995. Remediation and rehabilitation of oil-contaminated lake beds. J. AridLand Stud. 5,195–198.

Al-Awadhi, N., Al-Daher, R., ElNawawy, A., and Balba, M.T. 1996. Bioremediation of oil contami-nated soil in Kuwait. I. Landfarming to remediate oil-contaminated soil. J. Soil Contamination.5(3),243–260.

Bartha, R. and Pramer, D. 1965. Feature of a flask and method for measuring the persistence andbiologeffects of pesticides in soil. Soil Sci. 100,68–70.

Bradford, M.L. and Krishnamoorthy, R. 1991. Consider bioremediation for waste site cleanup. Chem.Eng. Prog. 87(2),80–85.

Cerniglia, C.E. 1984. Microbial transformation of aromatic hydrocarbons. In: Petroleum Microbiol-ogy, 1st ed. pp. 99–129 (Atlas, R.M., Ed.) MacMillan, New York.

Field, J.A., DeJong, E.D., Costa, G., and DeBont, A.M. 1992. Biodegradation of polycyclic aromatichydrocarbons by new isolates of white rot fungi. Appl. Environ. Microbiol. 58(7),2219–2226.

Fogel, M.M., Tadeo, A.R., and Fogel, S. 1986. Biodegradation of chlorinated ethanol by a methaneutilizing mixed culture. Appl. Environ. Microbiol. 51(4),720–730.

Haggblom, M. (1990). Mechanisms of bacterial degradation and transformation of chlorinatedmonoaromatic compounds. J. Basic Microbiol. 30(2):115–120.

Leahy, J.G. and Colwell, R.R. 1990. Microbial degradation of hydrocarbons in environment. Microbiol.Rev. 54(3),305–315.

Lorch, H.J., Benckieser, G., and Ottow, J.C.G. 1995. Basic methods for counting microorganisms insoil and water. In: Methods in Applied Soil Microbiology and Biochemistry. pp. 146–161.(Alef, K. and Nannipieri, P., Eds.) Academic Press, New York.

Rogers, J.A., Tedaldi, D.J., and Kavanaugh, M.C. 1993. A screening protocol for bioremediation ofcontaminated soil. Environ. Prog. 12(2),146–156.

Salkinoja-Saonen, M. 1990. Biological remediation of soil contaminated by chlorophenol, LectureNo. 15. Application of special microorganism for wastewater treatment of water containingheavy metal held at 7th DECHEMA Conference. 12/13.0.3 DECHEMA, Frankfurt am Main,Germany.

Singer, M.E. and Finnerty, W.R. 1984. Microbial metabolism of straight chain and branched alkanes.In: Petroleum Microbiology, 1st ed. pp. 1–60 (Atlas, R.M., Ed.) MacMillan, New York

U.S. EPA (U.S. Environmental Protection Agency). 1986. Testing methods for evaluating solidwaste, 3rd edition. Office of Solid Waste and Emergency Response, SW-846, Washington,D.C.

Walters, G., Zilis, K., Wessling, E., and Hoffman, M. 1989. Analytical methods for petroleumhydrocarbon. Volatile Organics Control. pp. 620–623.

Vala, R. and Sakinoja-Sanonen, M. 1986. Bioreclamation of chlorophenol-contaminated soil bycomposting. Appl. Microbiol. Biotechnol. 25,68–74.

340278.pgs 3/15/01, 5:44 PM209

Dow

nloa

ded

by [

Nor

th D

akot

a St

ate

Uni

vers

ity]

at 1

9:34

26

Oct

ober

201

4