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Removal of Dissolved Organic Nitrogen from Surface Water and Reclaimed Water by Coagulation

지표수 및 재이용수내 용존 유기질소의 응집처리

  • Lee, Wontae (School of Civil and Environmental Engineering, Kumoh National Institute of Technology) ;
  • Choi, June-Seok (Korea Institute of Construction Technology) ;
  • Oh, Hyun Je (Korea Institute of Construction Technology)
  • Received : 2012.11.06
  • Accepted : 2012.11.19
  • Published : 2012.11.30

Abstract

During chlorination processes dissolved organic nitrogen (DON) can form toxic nitrogenous disinfection byproducts and organic chloramines which have little or no bactericidal activity. DON needs to be removed before chlorination processes to reduce the formation of those products. This study investigated the removal of DON from surface water and reclaimed water by coagulation with aluminum sulfate (alum) and a cationic polymer (polyDADMAC). Removal characteristics of dissolved organic carbon (DOC) and ultraviolet absorbance at 254 nm ($UVA_{254}$) were compared with that of DON. Coagulation with alum removed DON, DOC, and $UVA_{254}$ with similar trends, but the removal of $UVA_{254}$ was highest. A dual coagulation strategy of alum and cationic polymer improved the removal of DON. Coagulation with cationic polymer alone was not effective due to its narrow range of charge neutralization. DON in reclaimed water was easier to remove than that in surface water, and higher molecular weight fraction (>10,000 Da) of DON was preferentially removed.

용존유기질소(DON)는 염소와 반응하여 인체에 유해한 질소계 소독부산물과 소독능을 저하시키는 유기성 클로라민을 생성할 수 있다. 이러한 물질의 생성을 줄이기 위해서는 소독공정 전에 DON의 제거가 필요하다. 본 연구는 DON을 함유하는 지표수와 재이용수를 이용하여 응집실험을 하고 알루미늄염(alum)과 고분자응집제(polyDADMAC)에 의한 DON의 제거특성을 조사하였다. 또한 DON, 용존유기탄소(DOC), 254 nm 자외선 흡광물질($UVA_{254}$)의 제거율 및 제거 기작을 비교하였다. 지표수와 재이용수 모두 alum 응집제의 주입농도를 증가시킴에 따라 DON, DOC, $UVA_{254}$ 제거율이 점진적으로 증가하였는데, 원수특성과 상관없이 소수성 유기물을 나타내는 척도인 $UVA_{254}$의 제거율이 가장 높았다. 지표수와 재이용수 모두 alum 응집제만 주입한 경우보다 고분자응집제를 같이 주입한 경우 DON의 제거율이 높게 나타났다. 고분자응집제의 전하중화가 작용하는 적정농도범위가 좁아 고분자응집제만 주입하기 보다는 무기응집제와 같이 주입하는 하는 것이 바람직하다. 상대적으로 생성된 후 오랜 시간이 지나지 않은 재이용수의 DON 제거율이 지표수의 DON 제거율보다 높았고, 지표수와 재이용수 모두 10,000 Da 이상 분자량의 DON 제거율이 높게 나타났다.

Keywords

References

  1. Bull, R. J. and Robinson, M., "Carcinogenic activity of haloacetonitrile and haloacetone derivatives in the mouse skin and lung," In Water Chlorination, Chem., Environ. Impact and Health Effects, 5, 221-227(1983).
  2. Bull, R. J., Bull, M. and Reckhow, D. A., "Use of quantitative structure toxicity relationships (QSTR) to identify disinfection by-products of potential health importance," Proceedings of AWWA Water Quality Technology Conference, San Antonio, USA(2004).
  3. Lee, W., Westerhoff, P. and Croue, J. P., "Dissolved organic nitrogen as a precursor for chloroform, dichloroacetonitrile, N-nitrosodimethylamine, and trichloro-nitromethane," Environ. Sci. Technol., 41(15), 5485-5490(2007). https://doi.org/10.1021/es070411g
  4. 손희종, 황영도, 노재순, 빈재훈, "합성유기질소 성분에서의 염소 소독부산물 생성 특성," 대한환경공학회지, 32(5), 523-530(2010).
  5. 이원태, "염소 소독시 DON이 유기성 클로라민 생성에 미치는 영향," 대한환경공학회지, 33(7), 487-490(2011).
  6. Wolfe, R. L., Ward, N. R. and Olson, B. H., "Interference in the bactericidal properties of inorganic chloramines by organic nitrogen compounds," Environ. Sci. Technol., 19(12), 1192-1195(1985). https://doi.org/10.1021/es00142a009
  7. Vilge-Ritter, A., Masion, A., Boulange, T., Rybacki, D. and Bottero, J. Y. "Removal of natural organic matter by coagulation- flocculation: A pyrolysis-GC-MS study," Environ. Sci. Technol., 33(17), 3027-3032(1999). https://doi.org/10.1021/es981232p
  8. Pietsch, J., Sacher, F., Schmidt, W. and Brauch, H. J., "Polar nitrogen compounds and their behaviour in the drinking water treatment process," Water Res., 35(15), 3537-3544 (2001). https://doi.org/10.1016/S0043-1354(01)00086-0
  9. APHA, AWWA, WEF, "Standard Methods for the Examination of Water and Wastewater," American Public Health Association, Washington, DC(1998).
  10. Esparza-Soto, M., Lee, W., Mash, H. and Westerhoff, P. "Dissolved organic nitrogen removal during coagulation and PAC treatment," Proceedings of AWWA Annual Conference and Exhibition, New Orleans, Louisiana, USA(2002).
  11. Lurie, M. and Rebhun, M., "Effect of properties of polyelectrolytes on their interaction with particulates and soluble organics," Water Sci. Technol., 36, 93-101(1997).
  12. Montgomery, J. M., "Water Treatment Principles and Design," John Wiley and Sons. New York(1985).
  13. Leenheer, J. A. and Croue, J. P., "Aquatic organic matter," Environ. Sci. Technol., 37, 18A-26A(2003). https://doi.org/10.1021/es032333c
  14. Letterman, R. D., Amirtharajah, A. and O'Melia, C. R., "Coagulation and flocculation," In: Water Quality & Treatment. McGraw Hill, New York, pp. 6.1-6.66(1999).