Journal of Ecology and Rural Environment ›› 2020, Vol. 36 ›› Issue (8): 1080-1088.doi: 10.19741/j.issn.1673-4831.2019.0905

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Study on Nitrogen Removal Characteristics of Swine Wastewater in the Constructed Wetland Systems of Canna indica, Pontederia cordata and Iris pseudacorus

XIA Meng-hua1,2, LIU Ming-yu1,2, GUO Ning-ning3, YE Lei4, LI Xi1, LI Yu-yuan1, ZHANG Man-yi1, WU Jin-shui1   

  1. 1. Institute of Subtropical Agriculture, Chinese Academy of Sciences/Key Laboratory of Agro-Ecological Processes in Subtropical Region, Changsha 410125, China;
    2. University of Chinese Academy of Sciences, Beijing 100049, China;
    3. College of Resources and Environmental Sciences, Hunan Normal University, Changsha 410006, China;
    4. College of Engineering, Hunan Agricultural University, Changsha 410128, China
  • Received:2019-11-11 Published:2020-08-21

Abstract: Wetland plants are one of the critical components of the constructed wetland, and wetland systems constructed by different plants have different nitrogen removal characteristics. In this study, three emerged plants, Canna indica, Pontederia cordata and Iris pseudacorus, were selected for the field control experiment under the hydraulic retention time of 7 days. The nitrogen removal characteristics of the three plants on treating swine wastewater were investigated. The results show that the removal rates of TN, NH4+-N, and NO3--N were P. cordata > I. pseudacorus > C. indica, and the nitrogen removal loads were 3.93, 3.74 and 2.96 g·m-2·d-1, respectively. Among the wetland systems of the three emergent plants, microbial transformation was the most important way to the removing of nitrogen, accounting for 66%, 73%, and 64% of the total nitrogen removal amount, respectively, and the amount of sediment adsorption (13%, 10%, and 22%) and plant uptake (21%, 17%, and 14%) were lower. P. cordata had the largest biomass, the best growth and nitrogen removal rate and was suitable to be the pioneer plant for swine wastewater treatment. The root system of I. pseudacorus was the most developed, and it grew well under low temperature conditions, which can be a seasonal complement to P. cordata. C. indica can grow well in the swine wastewater, but its purification capacity was weak.

Key words: swine wastewater, constructed wetland, Pontederia cordata, Iris pseudacorus, Canna indica, nitrogen removal characteristic

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