Journal of Korean Society of Water and Wastewater (상하수도학회지)

The Korean Society of Water and Wastewater (대한상하수도학회)
권호 표지

Treatment Characteristics and Application of DAF Process for Effective Solid Separation in BNR Municipal Wastewater Treatment System

BNR 하수처리시스템에서 효과적 고형물 분리를 위한 DAF 공정의 적용과 처리특성

  • Received : 2010.02.20
  • Accepted : 2010.05.30
  • Published : 2010.06.15
Download PDF
⟨ Previous Next ⟩

Abstract

Many plants have been improved to adapt the target of the biological treatment processes changed from organics to nutrients since the water quality criteria of effluent was reinforced and included T-N and T-P for the municipal wastewater treatment plant. To meet the criteria of T-N and T-P, the conventional biological reactor such as aeration tank in activated sludge system is changed to the BNR (biological nutrient removal) processes, which are typically divided into three units as anaerobic, anoxic and oxic tank. Therefore, the solid separation process should be redesigned to fit the BNR processes in case of the application of the DAF (dissolved air flotation) process as an alternatives because the solid-liquid separation characteristics of microbial flocs produced in the BNR processes are also different from that of activated sludge system as well. The results of this study revealed that the microbial floc of the anaerobic tank was the hardest to be separated among the three steps of the unit tanks for the BNR processes. On the contrary, the oxic tank was best for the removal efficiency of nutrients as well as suspended solid. In addition, the removal efficiency of nutrients was much improved under the chemical coagulation treatment though coagulation was not indispensable with a respect to the solid separation. On the other hand, in spited that the separation time for the microbial floc from the BNR processes were similar to the typical particles like clay flocs, over $2.32{\times}10^3$ ppm of air volume concentration was required to keep back the break-up of the bubble-floc agglomerates.

Keywords

References

  1. Edzwald J.K. (1995), Principles and applications of dissolved air flotation, Water Science and Technology, 31(3-4), pp.1-23. https://doi.org/10.1016/0273-1223(95)00200-7
  2. Jung, H.-J., Lee, J.-W. Choi, D.-Y. Kim, S.-J. Kwak, D.-H. (2006), Flotation Efficiency of Activated Sludge Flocs using Population Balance Model in Dissolved Air Flotation, Journal of Korean Chemical Engineering, 23(2), 271-278. https://doi.org/10.1007/BF02705726
  3. Han M.Y., Park Y. H. and Yu T.J. (2002) Development of new method of measuring bubble size. Water Science and Technology: Water Supply, 2(2), pp.77-83
  4. Kwak, D.H., Jung, H.J., Kim, S.J., Won, C.H., Lee, J.W. (2005), Separation Characteristics of Inorganic Particles from Rainfalls in Dissolved Air Flotation: A Korean Perspective, Separation Science and Technology, 40, 3001-3016. https://doi.org/10.1080/01496390500338144
  5. Kwak, D.H., Jung, H.J., Kwon, S.B., Lee, E.J., Won, C.H., Lee, J.W. and Yoo, S.J. (2009), Rise Velocity Verification of Bubble-Floc Agglomerates Using Population Balance Model in DAF Process, Journal of Water Supply: Research and Technology-AQUA, 58(2), 85-94. https://doi.org/10.2166/aqua.2009.021
  6. Kwak, D.H., Yoo, S.J. Lee, E.J. and Lee, J.W. (2010), Evaluation on simultaneous removal of particles and off-flavors using population balance for application of powdered activated carbon in dissolved air flotation process, Water Science & Technology-WST, 61(2), 323-330. https://doi.org/10.2166/wst.2010.830
  7. Packham, R. F., and Richards, W. N. (1972), Water Clarification by Flotation-1, Water Research Association, November.
  8. Vrablick, E. R. (1959), Fundamental Principles of Dissolved-air Flotation of Industrial Wastes, West Lafayette, Ind. Proc. 14th Annu. Purdue Industrial Waste Conference.
  9. 곽동희, 김성진, 임영환 (2004), 용존공기부상(DAF) 공정을 이용한 생물학적 플록의 부상분리, 상하수도학회지, 18(5), 649-655.
  10. 김성진, 강병준, 박상욱, 이재욱, 정흥조, 곽동희 (2006), 미세기포에 의한 활성슬러지의 부상특성, 상하수도학회지, 20(4), 501-507.