Degradation Kinetics of Petroleum Contaminants in Soil-Water Systems

Vol. 78 No.3ACTA GEOLOGICA SINICAJune 2004825-828Degradation Kinetics of Petroleum Contaminants in Soil-Water SystermsZHENG Xilai', WANG Bingchen2, LI Yuying' and XIA Wenxiang'1Institute of Environmental Science and Engineering, Ocean Universityof China, Qingdao, Shandong 266003; E-mail: zhuxilai@mail. ouc. edu.cn2 Comprehensive Institute of Geotechnical Survey, Beijing 100007systrm in the Shenyang-Fushun sewage rrigation area, the physical-chemical-biological compositions of the unsaturatedzone is analyzed stemetially in this paper. At the same timne, the degradation kinetics of residual and aqueous oils isdetermined through biodegadation tests. The studies show that dominant microorganisms have been frmed in the soilsafter long-term sewage imigation. The microorganisms mainly include bacteria, and a few of fungus and actinomycetes.After a 110-days' biodegradation test, the degradation rate of residual oil is 9.74%-0.63%, while the degadation rate ofaqucous oil reaches 62 43%. This idicacs that the degradaion rate oflowccarbon residual oil, In adition, although microbial degradation of petoleum contaminants in soils is suitabl to the frst-order kinetics equation, the hal-lives of aqueous oil, No.20 heavy diecsel and residual oil in the surface soils (L2-1, S1-1and X1-1) arc 1732 b, 3465 h and 17325 h, respectively.Key words: dominant microorganisms, soil residual oil, aqueous oil, biodegradation rate1 Introductionhydrocarbons degrading microorganisms, which can live insurface water, soil and groundwater. Atlas (1981) analyzedPetroleum hydrocarbons contain many kinds of toxicwater samples from 12 petroleum-contaminated aquifers,substances, and their toxicity increases in a sequence ofwhich shows that there are about 100 bacteria per mililiteralkenes, cycloalkanes and aromatic hydrocarbon. It iswater.acknowledged that many carcinogenic, teratogenic andIn addition, Kincannon (1977) applicd land farming tomutagenic chemical substances come from petroleumtreat the petroleum-contaminated soil. As a result, alkenescontaminants, such as 3, 4-benzo pyrene, benzanthrene andreduced to 80% - 82% after 18 months' degradation.so on. The aqucous petroleum in soils can be concentratedTherefore, they think the method can be used to treatin the roots, stalks, leaves and seeds of crops under thepetroleum contaminants in the surface layer. Raymond andwastewater imigation, which result in the reduction of grainHudson (1976) and Jobson (1974) added 6 types of oilquality. In addition, the excessive adsorption of petroleumproducts to soils and then planted rutabaga and broad beanon the soil surface may influence the soil permeability andin the east, middle and west districts of the USA. Thechange the growth environment of crops. What needs to beresearch results showed that the average concenration ofpointed out is that petroleum hydrocarbon can solve cellvarious oils was reduced by 48.5%- 90% after one year'smembranes, disturb the enzyme system and result in thedegradation.pathological changes of the viscera like kidney and liverIn the 1970s and 1980s, Liu et al. (1981) and Liu andafter entering the buman body (Han et al, 1988).Yang (1984) studied the microbial ecology and degradationThe initial knowledge on the relation between petroleumin the Shenyang-Pushun sewage irigation area, whichand microorganisms commenced in the 1940s. At that time,indicaled that there was not evident petroleumthe interest was concentrated on the relationship ofaccumulation due to the formation of endemicmicroorganism and petroleum formation. In the 1950s andmicroorganisms and their degradation after 40- -50 years1960s, the basic theory and application of hydrocarbonpetroleum sewage irigation. In addition, through thedegradation became a new research field. Since the sinkingcolumn planigraphy test, Zhang and Li (2002) pointed outof the super oil tanker, TORRY CANYON in 1967, many .there was a sequence of degradation rate for threemicrobiologists began to study petrolcum contaminationpetroleum bydrocarbons: aromatic > alipbatic > resins.ecology, and did some research on the fate and influence ofConsidering the soil properties, microbial communitypetroleum contaminants (Huang et al, 1991; Lu, 2004).中国煤化工inants in the Shenyang-Alexander (1977) identified more than 30 kinds of:;s of residual oil, No.20:YHCNMHG826Degradation Kinetics of Petrolcum Contaminants in Soil-Water SystemsZheng et al.heavy diesel and aqucous oil in different layer areThe No. 20 heavy diesel is solved into ligroine for thedetermined in this paper.degradation tests of oil product, and their mixture is addedto the soil samples (L2-1, L2-2, S1-1, S1I-2, X1-1, X1-2)2 Physical Composition and Microbialaccording to the addition of oil in Table 3. And then, theyCharacteristics of Test Soilsare cultivated in an incubator at 20°C and with a watercontent 25% after 24 hours' volatilization at the ambientAll the soil samples are collected from the Shenyang-temperature.Fusbun sewage imigation area. Considering the history ofAs for the aqueous oil degradation test, 100 g of soilpetroleum contamination and the constitution osample is added into 1000 ml tap water supersaturated withunsaturated zone, three sampling sites are selected inpetroleum, in which the ratio of carbon, nitrogen andLishizhai, Sifangtai and Xingnong respectively In addition,phosphor (C: N: P) is 10:10: 1. After 30 days' inoculation,the soil profiles are re-divided into the top layer and bottomthe inoculated petroleum-saturated solution is added into alayer due to the discrepancy of soil propertics. Thekind of clean sandy clay at 25% soil moisture. And then, themechanical composition and main characteristics for thesarmples are cultivated in incubator at the 20°C. The oilsoil samnples are shown in Table 1.contents are also determined peridically. The results areThe microbial isolation and identification show thatlisted in the Table 3.endemic oilphilic microorganisms have occurred in theBased on the tests mentioned above, the results can beirrigation area after a long term petroleum sewage. Bacteriadrawn as follows:are the majority endemic microorganisms, which mainly(1) The degradation rate of residual oilaccumulated inincludes Pseudomonas， Xanthomonas, Plesiomonas,the soils is about 10% after 110 days' cultivation, which isAcinetobacter, and Brevibacterium. In addition, there are athe lower than that of the No. 20 heavy diesel and thefew of fungus and actinomycetes, which mainly includessoluble oil; .Penicillium and Aspergillus (see Table 2).(2) The degradability of the No. 20 heavy diesel ishigher; its degradation rate can reach above 45%. There are3 Petroleum Degradation Testthe background oil contents in the top soils of L2-1, S1-1and X1-1, so in the soil it is the mixture oil after the3.1 Methodsaddition of No. 20 heavy diesel into the soil. Therefore,Since the composition of the residual oil in soil istheir degradation rate is between the rate of residual oil anddifferent from that of petroleum product and aqueous oil,the rate of No.20 heavy diesel;their degradation tests are conducted separately.(3) The degradation rate of the aqueous oil is the highestAs for the degradation test of residual oil, 20 g of soil(62.43%).samples in the top layer (L2-1, S1-1 and X1-1) with thenatural moisture (about 25%) are added into a small3.2 Kinetics characteristic of oil degradationaluminum box in 20 replicate. And then, they are cultivatedBased on the test resuts in Table 3, the petroleumin an incubator at 20*C. The oil contents in soils arecontent in the soil decreases with the time of degradation.measured on the days of 0,2, 4, 8, 15, 25, 40, 60, 110 (sceAnd the relationship can be expressed as follows:Table 3).C= Coe-i(1Table 1 Mechanical composition and main characteristic of soil samplesSoil mechanical compositiooSampleOrganic TotalsiteLayercode Samp<0.001 0.001- 0.005 0.005- 0.01 0.01- 0.05 0.05-0.25 >0.2H cootenL FporosityDensitySoil lexturedepth(mm)om)(g/kg)(cm)Lishizhai toplayer L2-1 0-30 7.80.406.4033.8823.6020.92 6.2540.8147.91.38loambottom layer L2-2 30-130 3.244.062.2313.1742.3334.97 6.954.8743.81.49 sandy loanSifangai toplayer SI-1 0-25 11.78 13.4399250.239.565.5.5574.0250.2silty clay .bottomlayer S1-2 25-130 10.10 10.097.2150.4818.70 3.42 6.301143.0silty clayXingnoog toplayer X1-1 0-35 8.93 14.77.056.89中国煤化工49.81.38 sity claybottomlayer X1-2 35-130 8.95 15.810.1948.69 .YHCNMH(16.81.41 sity clayVol. 78 No.3ACTA GEOLOGICA SINICAJune 2004827Table 2 Dominant microorganisms in the petroleumwater and h is the degradation constant.contamination area*In addition, a first- order kinetics equation ofSoil sampleBacteriaFungibiodegradation can be derived from the Eq. (1). It can beBacillusPenicilium freguentan以expressed as:PlesiomonasPenicillum citrirumHCA top layerPseudomonasPenicillumn mquefortidC/dt=-AC(2)AcinetobacterAspergilus versicolorAt the same time, the half life (12) of oil degradation inKurhiaPenicillium patulunsoil water can be derived from the Eq. (2), and it can beBrevibacteriumCladosporiun herbanm_Peniclliun chrysogenumPlesiononasPerncllum vetin= 0.693/(3)bottom layerArthrobacterAspergillus migerThe degradation rate can be flcted from the A and tinXanthomonasAspergillus versicolorThe bigger the value of h (or the smaller the value of the 1n),Acinelobacterthe faster the degradation reaction.Penicillium chrysogenumThe kinetic equations and eigenwerts of oil degradationMCA top layerAnhrobacterPenicillium italicwmin soil and water can be drawn from the numericalPlesimonasPericlliumn implicatumnSaphylococeuscalculation (see Table 4). The results indicate that the half-Bailluslives of the aqueous oil, the No.20 heavy diesel and theresidual oil in the topsoil (L2-1, S1-1 and X1-1) are 1732 h,Penicillumn chrysogenum3465 h and 17325 h respectively.Pernicillum italicumEnterobactiaceae Altemaria4 ConclusionsPenicillum roquefortiPenicillium veimiculatumPenicillium. funienlosunOn the basis of the up-to-date researches and petroleumLCA toplayerPenicillum italicumcontamination problems of soil-water crop system in theFlavobacteriumAspergillus wentiAnthrobacterCladosporium herbanmShenyang-Fushun sewage imigation area, the physical-Enterobaetiaceaechemical-biological compositions of unsaturated zone haveBacilusPaecicomyces wariotibeen analyzed systematically in this paper. At the samePenicilion citrinumbottom luyerArthrobucterAsperillus candidustime the kinetics characteristic of residual oil and thesoluble oil in the soil are studied. According to the intensiveSiapyylococcustests stated above, the following conclusions can be* HAC: heavy conaminated area, MCA: medum- cnarminated wueax;derived:LCA: slightly contamiated arca(1) The studies show that there are dominant microbialpopulations in the soils after long-term sewage imigation.where Co is the initial oil concentration in the used soil orAmong the dominant microorganisms, the bacteria are thewater, C is the instantaneous oil concentration in the soil ormajor species, and the fungus and the actinomycetes are the .Table 3 Residual oil content in the soil wateroil contentOil conteat in the soil water (mg/)Sample(mg/)d2d8d25440d60d 80d 110ddegradation rateL2-1676.3671.5652.1638.9 632.4 631.7622.4618.0 609.0 604.410.63272931.091.4 876.0 84.1 838.2 822.3 791 764.5 731.9 716.23.09S1-11404.71389.2 1342.1 1326.2 1311.3 1301.4 1281.7 1269.2 1267.99.74271710.11711.2 1678.9 1644.1 1590.0 1521.1 1485.01445.8 1421.7 1420.916.91X1-1171.4174.4 168.9 162.1 160.0 1591 157.1 154.0 156.2 153.510.53313.2302.9284.0262.2 240.1 230.4 210.1 197.0 189.2 192.138.70S1-27.992.389.278.23.745.15X1-28.191.485.172.467.3 .61.459.056.4 56.71.347.71L2-26894.489.782.778.571.6中国煤化工51.945.02Aqucous oill18.116.915.214.3 12<62.43YHCNMHG828，Degradation Kinetics of Petroleum Contaminants in Soil-Water SystemsZhengct al.Table 4 Kinetics characteristic of petroleum degradationSoil sampleOil content (mg/)Kinetics equationCotlfhcientdegradation constant ([h)half live (h)L2-1y64.8000.73580.0000417325272-5.100000.89730.00007700SI-10.77150.0004472y-1649.100000.81920.000079900X1-1y=167 000.66750.00004417325 .36y-=7769-0200.787100023465S1-y-=82.23-0.00.70080.0002X1-2y=81.23e 0.0000.7227soluble oil8.1y=17.209e 10000.9680.00041732minors.hydrocatbons. Microbio. Rev, 45: 180 -209.(2) According to the degradation tests, the residual oilHan Changmian, Jiang Yongnian and Yang Shiyu, 1988. Thedegradation rate may reach 9.74%-10.63%, while thecharacteristic of petroleum hydrocarbon contamination indegradation rate of aqueous oil is as high as 62.43%.water and several questions in analysis. Environ. Sei. Technol,3:20-22in Chinese(3) Although microbial degradation of petroleumHuang Difan, Tan Shi and Yang Wenkuan, 1991. Petroleumcontaminants in the soils is suitable to first- order kineticsmicrobiology. Petroleum industry press, Bejng, China, 368-equation, the balf-lives of aqueous oil, No. 20 heavy diesel382 (in Chinese).and residual oil in the surface soils (L2-1, S1-1 and X1-1)Jobson, A., 1974. Effect of amendments on the microbialare 1732 h, 3465 h and 17325 h, respectively.utilization of oil applied to soil. Appl. Microbial, 27(10): 166 .171Kincannon,C.B.. 1977. Oil microbial degradation in soil,AcknowledgementsProceedings of Open Farum on Management of PetroleumRefinary Waste-water, 1977, Mrselle, France, 257- -263.Special thanks to Ms Zhang Dageng from the ShenyangLiu Qisong, Yang Guifen and Zhang Chunzhu, 1981. MicrobialAgriculural University for assistance in some laboratoryecology in petroleum sewage imigation and degradationresearch. Environ. Sci, 12 (3): 1-6 (in Chinese).work. Funding was provided by the Natioan NaturalLiu Qisong and Yang Guifen, 1984. Microbial effect of PAH inScience Foundation of China (40272108).petroleum sewage irigation area. Environ. Sci. J, 4(2): 185-192 (in Chinese),Manuscript rceived July 8, 2003Lu Anhuai, 2004. Environmental propertes of minerals andaccepted Nov. 20, 2003contaminants purified by the mineralogical method. AcnGeologica Sinica (English edition), 78(1): 191-202.edited by Xie GuanglianRaymond, RL, and Hudson, J.0, 1976. Oil degradation in soil.Appl. Enviror. 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