Korean Chem. Eng. Res., Vol. 45, No. 4, August, 2007, pp. 311-318 { ji h k hsk Çmls o 305-701 re o 373-1 (2007 6o 5p r, 2007 6o 6p }ˆ) Status of Soil Remediation and Technology Development in Korea Ji-Won Yang and You-Jin Lee Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), 373-1, Guseong-dong, Yuseong-gu, Daejeon 305-701, Korea (Received 5 June 2007; accepted 6 June 2007) k p rp Škmm v pp, mm vp v q p Škmmp p o o np p r. n l Šk mml r ep v l 1990 t Šk m op o r}rp o p mmšk o lp v p. mmšk o p } o oo oo, mmop r l r, r, lr p. l ~ ~ v, p o mm vll o lp ee p o v p mm p q~l rp } pl p l v k pv p p. p o ll q r p pv Škv, r p oo r p n l. l ~ p p l r Šk o p l v tp, p l p m q r p pn o, p o p p. prp mmškp op o mm v mm vp p l l p q rn p lk, l Škl pe m p o v rp p n. h Abstract Soil contamination in Korea has been accelerated every year. Because of their persistence and cumulative tendency in the environment, soil contaminants have potential long-term environmental and health concerns and it is estimated to cost enormous expense for clean-up. Korea government has legislated the law on conservation of soil environment in mid 1990s, and managed and treated hazardous wastes in contaminated sites as a remediation policy since then. Soil remediation technologies are classified into in-situ/ex-situ or biological/physico-chemical/thermal processes according to applied places or methods, respectively. In Korea, clean-up of polluted sites has been mostly carried out at military areas, railroad-related sites and small-scale oil spilt sites. For these cases, in-situ remediation technologies such as soil vapor extraction (SVE) and bioventing were mainly used. In recent days, an environmental-friendly soil remediation emerged as a new concept - for example, a new soil remediation process using nanotechnology or molecular biological study and an integrated process which can overcome the limitation of individual process. To have better applicability of remediation technologies, comprehensive understandings about the pollutants and soil characteristics and the suitable techniques are required to be investigated. Above all, development of environmental technologies based on the sustainability accompanied by public attention can improve soil environment in Korea. Key words: Soil Contamination, Remediation Technology, Pollutant, Clean-up 1. Škp p e p k rp ol pl q p, v rl k p p s p o To whom correspondence should be addressed. E-mail: jwyang@kaist.ac.kr p, r r p p. rp ˆ ov pv r p n r p e l mmp v. Škl p mmp l } v o pp e p v mm, v mm, mm p 2 mmp k l p~ ˆ l v rp m p p. 311
312 kvoëpov Škp p mmp v r rp n q l n p np n p p. mmp p l v k m p q tn, p mm Škl mmop ˆl pr r p rnp tn. Škp (Šk pq), k (Šk, n k~), (Šk )p k v l pp p vp p el l Šk mmp lk. Škmml r ep v mmškp o l n p v l, n l 1995 Šk r p rr Šk mm vm mmšk ol l m lp r}rp v l m. q 16sp Škmm vp vr p, p Šv pn ˆl mm tp p Š p. r rp mmeˆ Ž kp o Šk r Škmm o e ee kp v p. p l Šk r r e mmšk e r m q} r p l Škp r } l r o p l s rp ~ rp Šk o p v tp [1]. pm p Šk r p rr rl p l r r r p lp, vp mm} n l vrrp tv k q l ~ rrp ˆ Škmmp mm r v pl p o p e. n l 1994 r ol Šk r p eq mp, 1980 p o lp eq v l kv v tp l r pp v p p p v mm l p n. l n p Škmm o lp l qp o l Žk p f r p mmškp op o n k l p q m. 2. hji tn Škmmo mm vp Table 1. l s p Škmm r vlp t mmp teplp, l ~ lp o l p mmp r p. Šk l p p r p l p p, t p n t Šk Š l r pp, o p Šk e v l v Šk v mmeˆ p p ˆ [2]. n l t 6s(,,, p,, 6 ) o (BTEX(bezene, toluene, ethylbenzene, xylene)p o ˆ p TPH(total phetroleum hydrocarbons)), o p, PCB(polychlorinated biphenyls),, ek p 11 p Škmm v vr l p rp } q, kl,, TCE(trichloroethylene), PCE(tetrachloroethylene) p l 16sp vr l p. l r Škl mm Žk mm n vll mmeˆ s l Škmmp m mmškp r Šk r }p o q n o l Šk r p nm Škmm eˆs ee p. 2005 Šk r eˆs, r rp r Škmm Škmm n tp v kkp, 2001 l e vr Ni, Zn, F r ˆ., s v r 3,902vr t, 56vr(1.4%)l Škmm n tp m, mm v Ni 19vr, Cu 17vr, Zn 12vr, As 9v r t p v pp p p ˆ p, p l TPH 3vr, BTEX 2vrp n tp m [3]. Škmmp mmškp v m r v k p p p ll p vlp mm r l mmp l p p v k n p er Škmm e p r. Škmmp o p p e v v, o o v rqe, vl, t vlp p, vp n np s vt 81.6%l } pv kp, v rq o e p nl rp k 23% el p p k r p [4]. q v s 29 p t v t 26 (k 90%) q n nn l p mm p p lp n p mmp p e p r [5]. pm p e p rp Š kmm p pn l r, Škmm e v lp 2,432~7,427 p p, p vlp rp 7,649~7.958 ha p p p m [4]. p l le vlp Š kmmp v k pl r p Škmm p j p p. l m l rr l Škmm v pp, 2002~2005 Šk v mm q ˆ p r 2015 2020 l mm n v Table 1. Soil pollutants and pollution sources Pollution sources Origin of pollution Pollutants Refining and storage of petroleum Corrosion and leakage of pipes and BTEX, TPHs, PAHs, PCP etc. hydrocarbons storage tanks Storage tanks of toxic chemicals Corrosion and leakage of pipes and storage tanks VOCs, PAHs etc. Industrial area o45 o4 2007 8k Corrosion and leakage of pipes and storage tanks TPHs, chlorinated organic compounds (TCE, PCE, 1,1,1-TCE etc.), Raw chemicals (Toluene, Phenol etc.), heavy metals (Cd, Pb, Cr 6+, As, Hg etc.) Landfill site Landfill leakage Organic compounds, heavy metals, VOCs etc. Incineration plant Exhaust gas, incineration ash Dioxin, PAHs heavy metals (Pb, Cd etc.) Abandoned mines Mine tailing, mine water Mine tailing: heavy matals Mine water: heavy metals, acid wastewater Military site landfill, oil leakage, training field BTEX, PAHs, heavy metals etc.
p m [5]. p o o pr v v m mšk v r l 5,000l op np n p [5] 8,062l o~2s 1.395l op np n p m [4]. p p rp o o r}r p e erp. 3. k m p Š mmšk o p s n k, rp mmšk o Table 2m. o p mmškp } o l oo (in-situ)m oo (ex-situ) l v, mmp p v o mm v m m vp r. oo r p mmškp l p e } } rp p np, p l p np n rl v p k e m mp p o p p. pl oo p mm Škp ql vr } t p mm vp p r n oo l r p. q Škp v l p r pp r pp v m p n. p p mmop r l r, r, l r p. lr } p r l Šk p ml e p l Šk tl o l Table 2. Soil remediation technologies [6] Class Remediation technology In-situ technology Ex-situ technology Biological Physical/chemical Bioventing Enhanced biodegradation Natural attenuation Phytoremediation Chemical oxidation Electrokinetic separation Fracturing Soil flushing Soil vapor extraction Solidification/stabilization Thermal Thermal Biological Physical/chemical Biopiles Landfarming Composting Slurry-phase biological Chemical extraction Chemical reduction/oxidation Dehalogenation Soil washing Separation Solidification/stabilization Hot gas decontamination Incineration Thermal Open burn/open detonation Pyrolysis Thermal desorption Landfill cap Containment Landfill cap enhancement Cut-off wall Excavation Other technology Off-site disposal Retrieval mmšk o 313 p o vp eˆ k p. vp vr l l p l} (, 800~1,200 o C)m r l l p l} (l, 400~800 o C)p v ˆ. lr p } pl m p pq, p r mm vp r p p. p p r pp v rn o p qrp pp, l v } n p, t p nl pr m l } v kp m l o rp p. r }, o n, r n v pn l r r l p mmo p Šk v l ~ p eˆ, r / o l p eˆ, / r p Ë eˆ p p. Škv, Šk r, Šk }, r mm p pp r pp r nl mm p (v k, n,, ) Škp k pm, ph, o ˆ, p, rš, p pl m p. kr p mm vp p v rp ~ rm mm vp pl p p p eˆ p t r/kr rp rp p lk. r } p Šk rr eˆ p ~ s s p r e o p veˆ p l rp rrp p. l p mm p p tp qp p p lv r v p. o p, p mm l pp r s p l rp p. ~ mm vp mmvl qp nl lr }, mm vp mmvl n r } o p, r } k rn p. p o p mm p s m Švl rn p s v pp, p mm v l s p m m vl p rp mm l p, vp rnp pp p. p p p n rp np }, e mm p v vp p l o p r lk. 4. ji h k n Šk o p p p o mm vlp to r Škmm ve l p l er l o np. l mmškp op v o p l vl k n p vl mms m o lp v pp pl ~ ~ q l o lp v l. l q l v r } ( v )p 2000 150l o p r lpl. pm l 2006 v H l 50l o p l p rp t lp 2007 ot vl 120l o Korean Chem. Eng. Res., Vol. 45, No. 4, August, 2007
314 kvoëpov p r t l v p. ~ ~ vp nl 2003 l l 65l o p lp rqp mp 2005 l p l l 105l o p lp t l op v p [7]. l t vlp Škmm v lp 1995 ee pp, p qprp Šk op v o o 5 ro m q rp kp ~ l ro p vl op p lv p. 4-1. s h k [8, 9] e qp o r2 r } o lp p erp p r lp 2001 2003 v 106,500 m (k 32} )p vl 150l o p r 2 lp ee l (Fig. 1). 1996 p v s p o e e t, Šk m mp p l tv r s ee l. mmo p vp o TPHl r~ e t 52.5% Škmm n t(2,000 mg/l)p p ˆ p, BTEXl 7% n tp m. mm vp v e 5 m p l mp 2~3 m e p Škp e mm l. v l o p v opl p v l p o (free oil layer-lnapl)p v e l o p lp, v e p 80%l (Pb)p v v tp n t p l l. ql o pp o mmšk/ mmš k l /krp } mmškp, /kre /r, Šk mmškp, kr t pm Žp p r r } p rn m. vl Šk q, lˆ, pm Žp p 3 v o p rn l. Šk q p n mm, rš p rp Škp p m. p rp Šk q p rn p o ˆ p 10 6 CFU/g p, Šk ph 6~8 op, qp 9.8Ë10 3 ~6.0Ë10 5 CFU/g, ph 5.3~6.5 } eˆ o ph srrm p Œl q mep pn l m m p sr m. o o p mm l Šk q p } pp p Šk rp mm Škl lˆ p rn l. n lˆ q e 7~20 Š( 18 Š)p Škp Fig. 1. MoonHyun remediation site in Busan. o45 o4 2007 8k }, lˆ m l p m 800, 900 o C ˆ 40(C40) v op o l 55,000 ppm v } pl. kr ( 8 o) tl r o p m Žp p rn l,, mk, ph srr, Œ l p ov krq dp 2 mm o, d v}, v } edšp l. pm p o p rn, 2003 6o tp r t TPH q 33.9%(271/800 mg/kg), Šk r p r n t k 13.5%(271/2,000 mg/kg) r tp mp v s l ql tp r l r ˆ l. 4-2. q q ji h z t vlp t 1920~1930 p l ˆp r rl p oe, o p t v Škp t l mm p. pl p o l mm n 158 p tr pp mm p l n rp t vl Škmm v lp ee p. 1995 p 2003 v 25 l l 360l o p v lp v m. r~ p l o lp v p p r p erp [4]. p el o lq 7.83 kmp p 1995 3,841 op Œp l e rp o lp ee m. t vll, kl,, p p t mmp e p ˆ, klp n tp 17 m 8 l p s l. pl mmop oep v e p, } rvšp t, vl Š, Šk r n mm Škp l t vl p p~ m r rm [9]. p t vlp mm v lp np,, } q s,, q, mmšk }, o } e,, n r, r, mmšk },, eq, s, t p [10] mmop vp rp } Š op ql v pl v t p n p lr sq rrp vr p. l t mm Škp } o e,, p pn /kr, m r2 ~ pn p n, Œ p ~, r p e e t Žp e pp [11] kv p p rn o lp, q rnp o p evl v lk p p. 5. ji h k m i n l 2000 p Škr ee 434 p vl rn o p p Fig. 2m. t Škv r p oo r p p v
mmšk o 315 pq m ~, pm k n ˆ, aluminasuppoted noble metal p pp p t m ~p pn l q p lv p [15]. m ~p rp p p ƒ vl p rs [16]. Fig. 2. Soil remediation technologies applied in Korea (2000~2006). p (83.3%), p r np rp r oo p p lt p. oo p pp r ršv Škl oo p rn ˆ [7], p o rœ Šk v Švl p }p n erp. lr } r } p n r kv p p, }, lˆ }, } l v 2 mmp o p p p p n kv r~ p. }, }, } p ropp kv p, p mm p mr r l qq p tp p Škr p r ppp p [12]. o p v l 2 mmp ~r p p q rnl rp p [14]. p n l v mmp p rp p l r Šk o l l v tp. (NT) (BT) p ~ p l p l p p e v p. mm v sp t o nl n Škmmp r p o p PCE TCE m t p p l k o p e p. l p l p p p rp o l q. 5-1. l nk h/s ji s o 1~100 nm p p pq p vp q m p rqr, r, r p v. p p q sq, rl p k l k l pn l sp p rp eˆ p t p. pq sp vp sp p p vl rp v l mm vl p p, kl p pn l Šk v mm vp prp r s o p pp p l v p. p p oo Šk r l rn pq p l(reactive zone)p rp re rn, Šk p pq mmvl p p p eˆ p pn. rp 4Fe 3 + + 3BH 4 + 9H 2 O 4Fe 0Ë+3H 2 BO 3 +12H + +6H 2 m ~p p p p o nr rp r p p p. TCE, 1,1,1-trichloroethane p o nr m ~ rq k α-elimination, β-elimination, hydrogenolysis, hydrogenation p ˆm pp pl ethane p v s [17]. l m ~p pn k t p r l l p. Cr(VI)m Pb(II) m ~ p l Cr(III) Pb(0) o, p p pvp m ~l m ~p pn n 30 p n r pp p p l [18]. l v tl l p As(III) m As(V)l m ~p pn l, r l v l sp m ~l 1,000 p p p p m. p pp ph 4~9p ol rp, HCO 3, H 4 SiO 4 0, H 2 PO 4 2 qpmp sq nl p r ppp m [19]. m ~p o nrmp p p o p Ž, Šk v l p p p o q, r pn k v p e p [19]. l el m ~p d p l n rp m o ~l r m ~p rs ~p q n p e m. ~ kpm kv p pn l r m ~l p p p mp r ~ q n l }p d pp lp pl (Fig. 3, 4). r ~p ˆ n l rq p f Šk v p mm vp m ~p pn l rrp rp pp p. 5-2. n km l l l m n i mmškp r } p Šk p pn l mm vp eˆ rl q rp o, Š k p orr, r r l p p lv. Fig. 3. SEM images of the surface of membrane w/o (a) and w/immobilized nanoscale zero-valent irons (b). Korean Chem. Eng. Res., Vol. 45, No. 4, August, 2007
316 kvoëpov Fig. 4. Degradation of TCE using immobilized nanoscale zero-valent iron on cation-exchange membrane (a) and reuse of the membrane (b). Fig. 5. Molecular biological study for the analysis of microbial behavior and biodegradation mechanism for organic contaminants. r r v k npp l p v orq k l l r o m r, m, o n n e p l rp nr s p r. pl Šk/v o mm vp r qp ~r p r r p e q r p p l v p (Fig. 5)[20]. l k q r p pn p v l v p. Biofilml p v r l vp FISH(fluorescent in situ hybridization) pn, kp v p l v p qn v } p p p q k k p m [21]. T-RFLP(terminal restriction fragment length polymorphism) pn mm v p v p l v t 3 l 5 l tl kk p, sp l l vq t er pn p [22]. k biostimulation, bioaugmentation k r Šk o p p p rn r p vp DGGE(denaturing gradient gel electrophoresis) p f pl [23]. o45 o4 2007 8k l el o mmškl mm p t, mmškp r ol Š n p o pp, Šk o rl p v l v p. PCR(polymerase chain reaction) DNA l p q r p pn o mm Škl o op ˆ op n p Rhodococcus erythropolis sl t 4sp p mp, p p mmškl bioaugmentation p ~ l p rp o p n k v n t ~ nm o pp m. o l n t ~ mmškp o r pp kp e p v Š p ~ Škp o r pp skr rp sp o pp ˆ l. p e el v DGGE pn Šk vp e p v k Ž p ˆ (Fig. 6), p op v l mm p kvl r~r p p v pp k pl. s l, n t ~ n l mm p r p l p p Š p p vl n p tl lp DGGE Ž p ˆ
mmšk o 317 Fig. 7. Schematic diagram of electrokinetic remediation. Fig. 6. Change of microbial diversity by bioaugmentation of (N) indigenous and (G) foreign microorganisms. p p 4sp nl o mm l q p Š p ppp p p. pm p q r v p Šk v p p qnl p pp k, p sr eˆp f r o v eˆ p. 5-3. ji s kl l ~ mmop Šk v p r r, r, r o p rp rn p prp m op p l v l. p p mm mm Škp prp r o n p rp r n p l l v p. p p mm vp l p r rn, o p edšp n p p p p. p o 2 v p p n p rp r } p o r } p, mm p ˆ p pp eˆ o lr } p rn p p pn p. p m r r p pn rp p. r r(electrokinetics, EK)p r l l e q oo Šk r Škl r p r p f r q l p m pm vp p p o e mm p r p (Fig. 7). p rœ Š kl n rp k r pp s t, o m p pm mm vl t rn l m [24]. p Šk }/ r l o mm l } pp eˆ [25], r l rœ Šk l mm vp pp veˆ [26], r p pn l Šk mk p sr l r } p pp p [27] k rl l v l. l el r rp r e r r l r pp pl p r q n l mm p o r -r rl l v tp. mm vp o edš p m l el 2002 vrl e lp p p p p n v o r l l p. o o mm Šk/v p -k, -, - pp l pl k p pn n p rp rn p f mm vp r pp eˆ n rp r v p p l rp re m. TCE mm Škp r o Šk r /MEUF (micellar-enhanced ultrafiltration) r/œ v r(pervaporation) p rp re p p rn p p m (Fig. 8). oo r p Šk r l r M-TWO1030 5%m isopropyl alcohol 5% l pn m, 10 Pore volumep 90% p p r pp m. n rp rp nkp mm p r o Œ v r p rn l, p 5 g/l p p p r nkl 90% p p r pp lp pp sq m k Fig. 8. Schematic diagram of integrated remediation process for TCEcontaminated soil. Korean Chem. Eng. Res., Vol. 45, No. 4, August, 2007
318 kvoëpov mp m p p ll. MEUF rp r rp p rp l [28]. 6. oh mmšk op 2001 v p o lp e qp r pp, mmšk o l l v p. rp o p p r r np r r p p r pp, l p l l q r p ~ p pn p o p e p. o l l e e tl pl er ql vp p r rp rn p. p l p q rn p p o mm vl v r mm p m l p v r p Š n p p. p l mm s p o r ~ p p prp op p l v k p. l Škp ˆ p op p e o k pep tn Šk p v rp p n. p p vrl e lp l vol p l ld (M1-0412-00-0001). o45 o4 2007 8k y 1. Kim, J.-S., Policy of Soil Environmental Conservation Current Issues and the Future, Environment preservation, 6-9(2005). 2. Jeong, S.-W., Environmental Impact Assessment Schemes Considering Fate and Transport of Soil Contaminants, Research report, Korea Environment Institute(2003). 3. Ministry of Environment, Operational Results of Soil Network and Investigation of Actual Conditions in 2005, Korea(2006). 4. Park, Y.-H., Yoon, S.-S., Bang, S.-W., Kim, M.-J., Yang, J.-U. and Lee, Y.-H., Management and Remediation Policy of Contaminated Lands in Korea, Research Report, Korea Environment Institute(2002). 5. Lee, C.-H., Status and Prosect of Soil Remediation Industry, Konetic report, http://www.konetic.or.kr/. 6. http://www.frtr.gov/matrix2/section3/sec3_int.html. 7. Kwak, M., Prospect and Present Status of Soil Environmental Remediation Industry, J. KSEE, 29(3), 271-274(2007). 8. Ministry of Environment, Case Study of Soil Remediation Technology, Korea(2002). 9. Lee, J.-Y. and Moon, C.-H., Remediation and Reuse of Contaminated Site, J. Korean Geotechnical Society, 21(11), 26-44(2005). 10. Shin, J.-K., Case Study of Soil Pollution in Abandoned Mines, Symposium on Geological Disaster and Remediation Technology, Nov., Seoul, 95-116(2002). 11. Kim, M.-J., Cleanup and Remediation of Heavy Metal Contaminated Soil, Symposium on Geological Disaster and Remediation Technology, Nov. Seoul, 117-141(2002). 12. www.konetic.or.kr/env_info/report/13-6.pdf, Analysis of Current Status of Soil Remediation, Konetic report(2002). 13. Lee, J.-Y. and Park, K.-J., Current Status and Method of Soil Remediation Treatment in Korea, Konetic report, http://www. konetic.or.kr/. 14. Kim, K.-W., Emerging Remediation Technologies for the Contaminated Soil/groundwater in the Metal Mining Area, Econ, Environ., 37(1), 99-106(2004). 15. Tratnyek, P. G. and Johnson, R. L., Nanotechnologies for Environmental Cleanup, Nanotoday, 1(2), 44-48(2006). 16. Wang, C. and Zhang, W., Synthesizing Nanoscale Iron Particles for Rapid and Complete Dechlorination of TCE and PCBs, Environ. Sci. Technol., 31(7), 2154-2156(1997). 17. Amold, W. A. and Roberts, A. L., Pathways and Kinetics of Chlorinated Ethylene and Chlorinated Acetylene Reaction with Fe(0) Particles, Environ. Sci. Technol., 34(9), 1794-1805(2000). 18. Ponder, S. M., Darab, J. C. and Mallouk, T. E., Remediation of Cr(VI) and Pb(II) Aqueous Solutions Using Supported Nanoscale Zero-valent Iron, Environ. Sci. Technol., 34(12), 2564-2569 (2000). 19. Ryu, A. and Choi, H., Application of Nano-technology to Contaminated Soil/groundwater Remediation, J. KSEE, 29(3), 257-261(2007). 20. Lee, K.-K., Development of Environmental-friendly Technology for the Remediation of Soil/groundwater System, News & Information for Chemical Engineers, 22(2), 152-158(2004). 21. Daims, H., Taylor, M. W. and Wagner, M., Wastewater Treatment: a Model System for Microbial Ecology, Trends in biotechnology, 24(11), 483-489(2006). 22. Casiot, C., Pedron, V., Bruneel, O., Duran, R., Personné, J. C., Grapin, G., Drakidès, C. and Elbaz-Poulichet, F., A New Bacterial Strain Mediating As Oxidation in the Fe-rich Biofilm Naturally Growing in a Groundwater Fe Treatment Pilot Unit, Chemosphere, 64(3), 492-496(2006). 23. Baek, K. H., Yoon, B. D. and Kim, B. H., Monitoring of Microbial Diversity and Activity During Bioremediation of Crude Oilcontaminated Soil with Different Treatments, J. Microbiology and Biotechnology, 17(1), 67-73(2007). 24. Acar, Y. B., Gale, R. J., Alshawabkeh, A. N., Marks, R. E., Puppala, S., Bricka., M. and Parker, R., Electrokinetic Remediation: Basic and Technology Status, J. Hazard. Mater., 40(2), 117-137(1995). 25. Yang, J.-W., Lee, Y.-J., Park, J.-Y., Kim, S.-J. and Lee, J.-Y., Application of APG and Calfax 16L-35 on Surfactant-enhanced Electrokinetic Removal of Phenanthrene From Kaolinite, Eng. Geol., 77(3-4), 243-251(2004). 26. Park, J.-Y., Kim, S.-J., Lee, Y.-J., Baek, K. and Yang, J.-W., EK-Fenton Process for Removal of Phenanthrene in a twodimensional Soil System, Eng. Geol., 77(3-4), 217-224(2004). 27. Kim, S.-J., Park, J.-Y., Lee, Y.-J., Lee, J.-Y. and Yang, J.-W., Application of a New Electrolyte Circulation Method for the ex Situ Electrokinetic Bioremediation of a Laboratory-prepared Pentadecane Contaminated Kaolinite, J. Hazard. Mater., 118(1-3), 171-176(2004). 28. Ministry of Science and Technology, Integrated Remediation of Underground Environment by Applying Micro-interfacial Phenomena, Research Report of National research laboratory program, Korea(2004).