Journal of Korean Society of Environmental Engineers (대한환경공학회지)

Korean Society of Environmental Engineers (대한환경공학회)
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A Study on Fouling Characteristics and Applicability of Fouling Reducer in Submerged MBR Process

침지형 MBR공정에서 파울링 특성과 파울링 완화제의 적용성에 관한 연구

  • Park, Jun Won (Department of Environmental Engineering, University of Seoul) ;
  • Park, Hong June (Department of Environmental Engineering, University of Seoul) ;
  • Kim, Min Ho (Department of Environmental Engineering, University of Seoul) ;
  • Oh, Yong Keol (Department of Environmental Engineering, University of Seoul) ;
  • Park, Chul Hwi (Department of Environmental Engineering, University of Seoul)
  • 박준원 (서울시립대학교 환경공학과) ;
  • 박홍준 (서울시립대학교 환경공학과) ;
  • 김민호 (서울시립대학교 환경공학과) ;
  • 오용걸 (서울시립대학교 환경공학과) ;
  • 박철휘 (서울시립대학교 환경공학과)
  • Received : 2012.09.03
  • Accepted : 2013.05.14
  • Published : 2013.05.30
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Abstract

Though MBR process has many advantages, the greatest risk factors in operating MBR process are occurrence of membrane fouling and decrease of flux. It is very difficult to find exact mechanism due to complex influence by many effects, although there have been recently many studies of membrane fouling. The purposes of this study are firstly evaluating bioreactor of lab-scale and micro-filtration hollow fiber membrane, secondly investigating correlation between foulants affecting membrane performance and membrane fouling, and lastly evaluating various parameters affecting fouling and applicability of membrane fouling reducer. This study found that TMP was increasing rapidly and showed 0.32 bar and the average of flux was 88 LMH. EPS concentration tends not to change much above MLSS concentration (6,000 mg/L). However, EPS concentration variation is wide below MLSS concentration (6,000 mg/L). Also, from results of membrane surface condition and element analysis using SEM/EDX, carbon and fluorine were founded to be the highest percentage in membrane because of characteristics of membrane material. In operating continuously, inorganic fouling was generated by increase of these inorganic substances such as $Al^{3+}$ and $Mg^{2+}$. Lastly, the best filtration performance was obtained for 0.03 mg MFR/mg MLSS by results of particle size, zeta potential, $SCOD_{cr}$, EPS and MLSS concentration.

MBR공정의 여러 가지 장점에도 불구하고 현장적용에 있어서 가장 큰 제한요소로 작용하는 것은 운전이 지속됨에 따라 멤브레인 파울링이 발생하여 플럭스의 저하가 발생하는 것이다. 현재 멤브레인 파울링에 관한 수많은 연구가 진행되고 있으나, 여러 가지 원인들이 복합적으로 영향을 미치기 때문에 정확한 메커니즘을 밝히기 어려운 실정이다. 본 연구에서는 lab-scale의 생물반응조와 정밀여과 중공사 멤브레인의 성능을 평가하고, 멤브레인 성능에 영향을 미치는 오염물질들을 측정하여 파울링과의 상관관계를 규명하고자 하였다. 마지막으로 파울링을 일으키는 다양한 인자들과 파울링 완화제(Membrane Fouling Reducer, MFR)의 적용성을 평가하였다. 실험결과 88 LMH로 임계 플럭스가 결정되었으며, 그때의 한계압력은 0.32 bar로 나타났다. MLSS농도와 EPS농도의 상관관계에서는 MLSS농도가 6,000 mg/L 이하에서는 EPS농도의 변화 폭이 큰데 비하여 6,000 mg/L 이상에서는 변동폭이 줄어드는 것을 확인할 수 있었다. 또한 SEM/EDX를 이용하여 멤브레인 표면 상태와 원소분석을 측정한 결과 탄소와 불소가 멤브레인의 재질 특성상 가장 높은 비율을 차지하였으며 알루미늄, 마그네슘과 같은 무기물의 비율이 증가한 것으로 보아 운전이 지속됨에 따라 무기성 멤브레인 파울링이 발생한 것으로 판단된다. MFR주입량에 따른 혼합액의 특성 변화를 측정하기 위해 입도분석, 제타전위, SCODcr, EPS 및 MLSS농도를 비교분석한 결과 전반적으로 0.03 mg MFR/mg MLSS의 MFR을 주입하였을 때 가장 좋은 결과를 나타내었다.

Keywords

References

  1. Yamamoto., "Direct solid-liquid separation using hollow fiber membrane in an activated sludge aeration tank," Water Sci. Technol., 21, 43-54(1989)
  2. Chiemchaisri., "Organic stabilisation and nitrogen removal in a membrane separation bioreactor for domestic wastewater treatment," Water Sci. Technol., 28, 325-333(1992)
  3. Field, R. W., "Critical flux for microfiltration fouling," J. Membr. Sci., 100, 259-272(1995) https://doi.org/10.1016/0376-7388(94)00265-Z
  4. Brown, M. J., "Comparison of bacterial extracellular polymer extraction methods," Appl. Environ. Microbiol., 40, 179-185(1980)
  5. Sperandio, M., "Characterization of sludge structure and activity in submerged membrane bioreactor," Water Sci. Technol., 52(10-11), 401-408(2005)
  6. Lowry, O. H., "Protein measurement with the folin phenol reagent," J. Biol. Chem., 193, 265-275(1951)
  7. Dubois, M., "Colorimetric method for determination of sugars and related substances," Anal. Chem., 28, 350-356(1956) https://doi.org/10.1021/ac60111a017
  8. Damayanti, A., "The influenced of PAC, zeolite, and Moringa oleifera as biofouling reducer (BFR) on hybrid membrane bioreactor of palm oil mill effulent," Bioresour. Technol., 102, 4341-4346(2011) https://doi.org/10.1016/j.biortech.2010.12.061
  9. Le Clech, P., "Critical flux determination by the flux-step method in a submerged membrane bioreactor," J. Membr. Sci., 227(1-2), 81-93(2003) https://doi.org/10.1016/j.memsci.2003.07.021
  10. Frolund, B., "Extraction of extracellular polymers from activated sludge using a cation exchange resin," Water Res., 30(8), 1749-1758(1996) https://doi.org/10.1016/0043-1354(95)00323-1
  11. Lu, S. G., "A model for membrane bioreactor process based on the concept of formation and degradation of soluble microbial products," Water Res., 35(8), 2038-2048(2001) https://doi.org/10.1016/S0043-1354(00)00461-9
  12. Hong, S., "Kinetics of permeate flux decline in crossflow membrane filtration of colloidal suspensions," J. Colloid Interface Sci., 196, 267-277(1997) https://doi.org/10.1006/jcis.1997.5209
  13. Schafer, A. I., "Removal of natural hormones by nanofiltration membranes: measurement, modeling and mechanisms by wastewater effluents," Environ. Sci. Technol., 38, 1888-1896(2004) https://doi.org/10.1021/es034952r
  14. Lee, W. N., "Changes in biofilm architecture with addition of membrane fouling reducer in a membrane bioreactor," Proc. Biochem., 42, 655-661(2007) https://doi.org/10.1016/j.procbio.2006.12.003
  15. Jang, N., "Comparison of membrane biofouling in nitrification and denitrification for the membrane bioreactor," Water Sci. Technol., 53, 43-49(2006)

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