Performance Evaluation of Constructed Wetlands Treating Wastewater Treatment Plant Effluent in Taihu Lake,China |
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| Authors: | Xiaoxiao Shen Dechun Huang Changzheng Zhang Kai Hu |
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| Affiliation: | 1. Hohai University, Nanjing, P.R. China;2. Collaborative Innovation Center of World Water Valley and Water Ecological Civilization, Jiangning, Nanjing, P.R. China;3. Hohai University, College of Environment, Gulou, Nanjing, P.R. China;4. Hohai University, Key Laboratory of Integrated Regulation and Resources Development of Shallow Lakes of Ministry of Education, Gulou, Nanjing, P.R. China |
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| Abstract: | Constructed wetlands are often used for advanced treatment of the secondary effluent of municipal wastewater treatment plants (WWTPs). Through assessing wetlands based on economic, technical, environmental, and social impacts, an optimal process is selected. In this study, a set of assessment methods for wetland treatment technology is established: The analytic hierarchy process (AHP) is used to establish the evaluation index system; the entropy weight method is employed to calculate the index weights; and the preference ranking organization method for enrichment evaluation (PROMETHEE) is utilized for ranking of the selected treatment technologies. Then four processes applied in Taihu Lake basin, China are evaluated. The results show the following ranking: Vertical‐flow wetland–ecological pond–surface‐flow wetland–horizontal‐flow wetland, vertical‐flow wetland–horizontal‐flow wetland, ecological pond–horizontal‐flow wetland–surface‐flow wetland, and ecological ditch–ecological pond. The wetland exhibits certain universality and space portability with regard to treatment of municipal WWTP effluent. From the view of comprehensive benefits, the ranking of the treatment technology based on the vertical‐flow wetland is high (Φ values between 0.0224 and 0.0349), whereas that based on the ecological pond is low (Φ values between ?0.2086 and ?0.2652), owing to the mechanism of the process itself and the role of microorganisms in the system. Moreover, for organic matter removal, a vertical‐flow wetland process is recommended (48%), whereas for the removal of N contamination, an integrated‐flow wetland process is suggested (31.2% for NH3‐N, 32.4% for TN removals). |
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| Keywords: | analytic hierarchy process pollutant removal PROMETHEE wastewater treatment |
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