Journal of Wetlands Research (한국습지학회지)

Korean Wetlands Society (한국습지학회)
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Clogging Potential in Constructed Vertical Flow Wetlands Employing Different Filter Materials for First-flush Urban Stormwater Runoff Treatment

도시 초기 강우유출수 처리를 위한 수직흐름습지에서 여재별 폐색 잠재성 분석

  • Chen, Yaoping (School of Earth and Environment, Anhui University of Science and Technology) ;
  • Guerra, Heidi B. (Department of Environmental Engineering, Hanseo University) ;
  • Kim, Youngchul (Department of Environmental Engineering, Hanseo University)
  • Received : 2018.03.15
  • Accepted : 2018.07.23
  • Published : 2018.08.31
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Abstract

The function of vertical subsurface flow wetlands can potentially be reduced with time due to clogging and are often assumed to be occurring when ponding and overflow is observed during rainfall. To investigate their clogging potential, three pilot-scale vertical subsurface flow (VSF) wetland systems were constructed employing woodchip, pumice, and volcanic gravel as main media. The systems received stormwater runoff from a highway bridge for seven months, after which the media were taken out and divided into layers to determine the amount and characteristics of the accumulated clogging matters. Findings revealed that the main clogging mechanism was the deposition of suspended solids. This is followed by the growth of biofilm in the media which is more evident in the wetland employing woodchip. Up to more than 30% of the clogging matter were found in the upper 20 cm of the media suggesting that this layer will need replacement once clogging occurs. Moreover, no signs of clogging were observed in all the wetlands during the operation period even though an estimation of at least 2 months without clogging was calculated. This was attributed to the intermittent loading mode of operation that gave way for the decomposition of organic matters during the resting period and potentially restored the pore volume.

운전시간이 경과함에 따라 공극폐색 문제로 인하여 수직 흐름형 습지의 기능은 저하되는데 이와 같은 문제는 폰딩(ponding)이나 월류 현상에 의하여 쉽게 관측할 수 있다. 공극폐색 잠재성을 조사하기 위하여 도로주변에 설치된 파일럿 규모의 습지 운전자료를 분석하였다. 습지에는 각각 우드칩과 마사(부석), 그리고 화산석을 충진하였다. 약 7개월 동안 도로 강우유출수 처리시험을 수행한 후 충진된 여재를 비운 후 여재 층별로 분류하여 여재에 의해 포획된 고형물 입자의 양과 특성을 분석하였다. 분석결과 대부분의 포획물질은 외부기인 부유물질 이었으며 다음으로 여재표면에 증식한 생물막인 것으로 나타났다. 특히 다른 여재와 비교하여 유기성 여재인 우드칩에서 생물막의 증식이 왕성하였다. 또한 전체 포획량 중 30% 이상이 상부 20cm 이내에 집중되어 있어 폐색으로 인한 폰딩 발생시 이 부분의 여재를 우선적으로 교체하여야 할 것으로 판단된다. 또한 모델계산 결과 우드칩 충진 습지에서 폐색에 도달하는데 약 2달 정도가 소요될 것으로 산출되었으나 실제로는 전혀 폐색 기미는 발생하지 않았는데 이는 강우시에만 운영되는 특성상 강우활동이 없는 무강우 기간 동안 포획된 유기물질이나 생물막이 자연적으로 분해되어 일정기간이 경과되면 공극이 회복되었다.

Keywords

References

  1. Bavor HJ, Schulz TJ (1993). Sustainable suspended solids and nutrient removal in large-scale, solid-matrix, constructed wetland systems, Constructed Wetlands for Water Quality Improvement, Moshiri GA (ed.), Lewis Publishers: Boca Raton, Florida, pp. 646-656.
  2. Blazejewski R, and Murat-Blazejewska S (1997). Soil clogging phenomena in constructed wetlands with subsurface flow. Water Science and Technology, 35(5), pp. 183-188. [DOI:10.1016/S0273-1223(97)00067-X]
  3. Bouwer, H (2002). Artificial recharge of groundwater: Hydrogeology and engineering. Hydrogeology Journal, 10(1), pp. 121-142. [DOI: 10.1007/s10040-001-0182-4]
  4. Hua, GF, Zhu, W, Zhao, LF, and Huang, JY (2010). Clogging pattern in vertical-flow constructed wetlands: Insight from a laboratory study. J. of Hazardous Materials, 180(1-3), pp. 668-674. [DOI:10.1016/j.jhazmat.2010.04.088]
  5. Kadlec, R and Wallace, SD (2009). Treatment Wetlands. CRC Press, Inc., Boca Raton, Florida.
  6. Langergraber, G, Haberl, R, Laber, J, Pressl, A (2003). Evaluation of substrate clogging processes in vertical flow constructed wetlands. Water Science and Technology, 48(5), pp. 25-34. [https://www.ncbi.nlm.nih.gov/pubmed/14621144]
  7. Larmet, H, Delolme, C, Bedell, J (2007). Bacteria and heavy metals concomitant transfer in an infiltration basin: Columns study under realistic hydrodynamical conditions. Proceedings of the NOVATECH 2007: 6th International Conference on Sustainable Techniques and Strategies in Urban Water Management, Lyon, France, pp. 615-622.
  8. Le Coustumer, S, Fletcher, TD, Deletic, A, Barraud, S, Poelsma, P (2012). The influence of design parameters on clogging of stormwater biofilters: A large-scale column study. Water Research, 46(20), pp. 6743-6752. [DOI: 10.1016/j.watres.2012.01.026]
  9. Li, H and Davis, AP (2008). Urban particle capture in bioretention media. II: Theory and model development. J. of Environmental Engineering, 134(6), pp. 419-432. [DOI: 10.1061/(ASCE)0733-9372(2008)134:6(419)]
  10. Platzer C, and Mauch K (1997). Soil clogging in vertical flow reed beds: Mechanisms, parameters, consequences and.......solutions? Water Science and Technology, 35(5), pp. 175-182. [DOI: 10.1016/S0273-1223(97)00066-8]
  11. Winter, KJ and Goetz, D (2003). The impact of sewage composition on the soil clogging phenomena of vertical flow constructed wetlands. Water Science and Technology, 48(5), pp. 9-14. [https://www.ncbi.nlm.nih.gov/pubmed/14621142]
  12. Yong, C, McCarthy, D, Deletic, A (2013). Predicting physical clogging of porous and permeable pavements. J. of Hydrology, 481, 48-55. [DOI: 10.1016/j.jhydrol.2012.12.009]
  13. Zhao YQ, Sun G, Allen SJ (2004). Anti-sized reed bed system for animal wastewater treatment: a comparative study. Water Research 38(12), pp. 2907-2917. [DOI:10.1016/j.watres.2004.03.038]
  14. Zhao, LF, Zhu, W, and Tong, W (2009). Clogging processes caused by biofilm growth and organic particle accumulation in lab-scale vertical flow constructed wetlands. J. of Environmental Science, 21(6), pp. 750-757. [DOI:10.1016/S1001-0742(08)62336-0]