Removal of Various Contaminations from Drainage by Using Free Water Surface and Submerged Surface Flow Wetland Systems

Abstract:

This study demonstrates an efficient approach to remove various liquid-phase pollutants from wastewater by using constructed wetland (CW) systems. The plant used in this study was phragmites communis. Two types of CW systems, free water surface flow and submerged surface flow wetlands, are used to compare with their efficiencies for removing chemical oxygen demand (COD), Zn²⁺, true color, and NH3-N from the drainage. Experimental results confirmed that the CW treatment displays excellent capability for removing the pollutants, i.e., high removal efficiencies. This finding indicates that the growth of phragmites communis enables well-developed root network in CW system, thus leading to a higher adsorption capacity. The growth period of the root network in our case takes about 40 days, forming the bio-membrane. On the basis of the present work, the presence of bio-membrane on the plant root not only enhances but also stabilizes the efficiencies for removing various contaminations from the wastewater.

• Periodical: Advanced Materials Research (Volumes 356-360)
• Pages: 2162-2168
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.356-360.2162
• Online since: October 2011
• Authors: Jung Pin Wang, Hsi Chi Yang, Chien Te Hsieh
• Keywords: Constructed Wetland, Free Water Surface Flow (FWS), Landfill, Phragmites communis, Submerged Surface Flow (SSF)

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[10] Akratos, C.S., and Tsihrintzis, V.A. (2007). Ecol. Eng. 29, 173. TABLE 1. Characteristics of experimental CW systems. Wetland type Layer thickness (cm) Plant coverage (%) HRTa (day) HLRb (m3/m2 day) FWS1 40 70 5.3 0.0343 FWS2 40 30 5.3 0.0343 SSF1 40 70 4.1 0.0343 SSF2 40 30 4.1 0.0343 a HRT: hydraulic retention time. b HLR: hydraulic loading rate. Figure 1. Schematic diagram of four types of wetland systems: FWS1, FWS2, SSF1, and SSF2. Figure 2. Variation of temperature with treating period: (a) FWS1 and FWS2 and (b) SSF1 and SSF2. Figure 3. Stable removal efficiencies at 100th day: (a) COD, (b) Zn2+, (c) ture color, and (d) NH3-N, for different types of wetland systems. Figure 4. Variation of removal efficiency of COD with treating period: (a) FWS1 and FWS2 and (b) SSF1 and SSF2. Figure 5. Variation of removal efficiency of Zn2+ ions with treating period: (a) FWS1 and FWS2 and (b) SSF1 and SSF2. Figure 6. Variation of removal efficiency of ture color ion with treating period: (a) FWS1 and FWS2 and (b) SSF1 and SSF2. Figure 7. Variation of removal efficiency of NH3-N with treating period: (a) FWS1 and FWS2 and (b) SSF1 and SSF2.