Surfactant Aided Air-sparging for Groundwater Remediation

계면촬성제 첨가에 따른 지하수 폭기법의 폭기효율 변화 연구

  • 소효은 (한림대학교 환경시스템공학과) ;
  • 최경민 (한림대학교 환경시스템공학과) ;
  • 이승재 (한림대학교 환경시스템공학과) ;
  • 김헌기 (한림대학교 환경시스템공학과)
  • Published : 2002.10.01

Abstract

Lab-scale experiments were conducted to evaluate the effect of surface tension reduction on the extension of the influence zone and the VOC removal efficiency of ground water sparging. A glass column packed with coarse sand was used for VOC removal test at two different surface tensions. A glass column without porous media was also used fer control purpose prior to sand-packed column test. A quasi-two-dimensional glass box model, packed with a sand, was used fer sparging zone tests at different water surface tensions. Surface tension of the aquoues solution used in this study was controlled using sodium dodecyl sulfate (SDS). For the glass, sand column experiments, total amount of air filled in the media increased as surface tension decreased. Toluene (used as VOC in this study) removal rate increased slightly with decreased surface tension f3r both free water column and sand-packed column. Air sparging zone extended up to 500% as the surface tension decreased. Combining the results from two different experiments, VOC removal efficiency is expected to increase significantly with surface tension reduction.

계면활성제를 사용하여 지하수의 표면장력을 인위적으로 감소하였을 때, 감소된 표면장력이 지하수 폭기시의 폭기 영향권 및 VOC 제거 효율에 미치는 영향을 실험실 규모의 실험을 통하여 규명하였다. 내경 9.5 cm, 길이 100 cm의 유리 컬럼에 계면활성제(sodium dodecyl sulfate, SDS) 및 toluene 100 ppm 포함하는 물로 채운 후 일정한 속도로 공기를 주입하였을 때의 toluene의 제거 속도를 측정하였다. 또한 같은 컬럼에 토양(모래)이 채워진 상태에서 동일한 실험을 반복하였다. 토양이 존재하지 않는 상태에서의 stripping에 의한 toluene의 제거 속도는 표면장력의 감소(계면 활성제 농도의 증가)에 따라 증가하는 것으로 나타났으며, 토양이 존재하는 경우에도 비슷한 결과를 나타내었다. 2차원 유리 상자에 모래와 SBS를 포함하는 물을 채운 후 일정한 공기 유속을 유지하였을 때, 폭기의 영향권(공기의 침투영역)은 물의 표면장력 감소에 따라 현저히 증가하는 것으로 나타났다. 특히 SDS의 critical micelle concentration(CMC)보다 훨씬 낮은 농도에서 폭기 영향권이 최대화하는 것으로 밝혀졌다. 본 연구결과는 폭기에 의한 지하수 오염물질 중, 특히 휘발성 유기오염물질의 제거 공정의 효율을 증대하는데 기여할 것으로 생각된다.

Keywords

References

  1. J. Envir. Engrg. v.126 Removal of dissolved- and free-phase benzene pools from ground water using in situ air sparging. Adams, J.A.;Reddy, K.R. https://doi.org/10.1061/(ASCE)0733-9372(2000)126:8(697)
  2. Water Resour. Res. v.34 Air sparging: Air-water mass transfer coefficients. Braida, W.J.;Ong, S.K. https://doi.org/10.1029/98WR02533
  3. J. Am. Chem. Soc. v.6 The determination of surface tension (free surface energy), and the weight of falling drops: The surface tension of water and benzene by the capillary height methold. Harkins, W.D.;Brown, E.E.
  4. J. Contam. Hydrol. v.33 Volatilisation and biodegradation during sparging of dissolved BTEX-contaminated ground water. Johnson, C.D.;Rayner, J.L.;Patterson, B.M.;Davis, G.B. https://doi.org/10.1016/S0169-7722(98)00079-5
  5. Environ. Sci. Technol. v.33 Effect of flow rate changes and pulsing on the treatment of source zones by in situ air sparging. Johnson, P.C.;Das, A.;Bruce, C. https://doi.org/10.1021/es9807688
  6. J. Contam. Hydrol. v.19 Air sparging in a sandy aquifer (Florence, Oregon, USA): Actual and apparent radius of influence. Lundegard, P.D.;LaBrecque, D. https://doi.org/10.1016/0169-7722(95)00010-S
  7. Ground Water Monitoring Rev. v.12 The application of in situ air sparging as an innovative soils and ground water remediation technology. Marley, M.C.;Hazebrouck, D.J.;Walsh, M.T. https://doi.org/10.1111/j.1745-6592.1992.tb00044.x
  8. Water Resour. Res. v.26 Dissolution of trapped nonaqueous phase liquids: Mass transfer characteristics. Miller, C.T.;Poirier-McNeill, M.M.;Mayer, A.S. https://doi.org/10.1029/WR026i011p02783
  9. Water. Resour. Res. v.27 Theoretical study of the significance of nonequilibrium dissolution of nonaqueous phase liquids in subsurface systems. Powers, S.E.;Loureiro, C.O.;Abriola, L.M.;Weber, W.J.Jr. https://doi.org/10.1029/91WR00074
  10. Environ. Sci. Technol. v.33 Field performance of air-sparging system for removing TCE from groundwater. Rabideau, A.J.;Blayden, J.M.;Ganguly, C. https://doi.org/10.1021/es980538t
  11. J. Envir. Engrg. v.124 System effect on benzene removal from saturated soils and ground water using air sparging. Reddy, K.R.;Adams, J.A. https://doi.org/10.1061/(ASCE)0733-9372(1998)124:3(288)
  12. Haz. Waste and Haz. Mat. v.12 A review of insitu air sparging for the remediation for the remediation of VOC-contaminated saturated soils and groundwater. Reddy, K.R.;Kosgi, S.;Zhou, J. https://doi.org/10.1089/hwm.1995.12.97
  13. Water Resour. Res. v.34 Air bubble migration in a granular porous medium: Experimental studies. Roosevelt, S.E.;Corapcioglu, M.Y. https://doi.org/10.1029/98WR00371
  14. Environ. Sci. Technol. v.34 Influence of porous media, airflow rate, and air channel spacing on benzene NAPL removal during air sparging Rogers, S.W.;Ong, S.K. https://doi.org/10.1021/es9901112
  15. Water Resour. Res. v.31 Mechanisms controlling vacuum extraction coupled with air sparging fro remediation of heterogeneous formation contaminated by dense nonaqueous phase liquids. Unger, A.J.A.;Sudicky, E.A.;Forsyth, P.A. https://doi.org/10.1029/95WR00172
  16. Water Resour. Res. v.34 Modeling of air sparging in a layered soil: Numerical and analytical approximation. van Dijke, M.I.J.;van der Zee;S.E.A. T.M. https://doi.org/10.1029/97WR03069
  17. Ground Water Monitoring Rev. v.12 The application of in situ air sparging as an innovative soils and ground water remediation technology Marley, M.C.;Hazebrouck, D.J.;Walsh, M.T. https://doi.org/10.1111/j.1745-6592.1992.tb00044.x