Qiong Wan1, Qingji Han2, Hailin Luo3, Tao He3, Feng Xue4, Zihuizhong Ye5, Chen Chen3, Shan Huang6. 1. School of Architecture and Civil Engineering, Xi'an University of Science and Technology, Xi'an 710054, China. 2. Xi'an Research and Design Institute of Wall & Roof Materials Co., Ltd., Xi'an 710061, China. 3. State Environmental Protection Key Laboratory of Urban Ecological Environment Simulation and Protection, South China Institute of Environmental Sciences, Ministry of Ecology and Environment of China, Guangzhou 510535, China. 4. Xi'an Pengyi Environmental Engineering co. Ltd., Xi'an 710054, China. 5. Stuart Country Day School, Princeton, NJ 08540, USA. 6. Department of Civil and Environmental Engineering, Princeton University, Princeton, NJ 08544, USA.
Abstract
Although constructed wetlands (CWs) are widely used around the world with various substrates, the mechanisms of how these modified substrates affect wastewater treatment are still unknown. In this study, CW microcosms were established with and without ceramsite as a substrate, and the wastewater treatment efficiencies were evaluated during 71 days of incubation. Using the 16S rRNA high-through sequencing, the mechanisms of how CW substrate changed the microbial community was quantified. The results showed that compared to soil as substrate, the use of ceramsite as substrate material enhanced the removal of pollutants from CW systems, particularly under a short retention time (1.5-day) condition. There were more beneficial microorganism groups (nitrogen, sulfur, phosphate) in the ceramsite CW system than the non-ceramsite CW system, particularly in the bottom layers. Moreover, the CW with ceramsite substrate had more nitrification function. All of these results suggested that the ceramsite CW system enhanced the removal of pollutants because it increased the concentration of key microbes that are necessarily for nutrient cycles.
Although constructed wetlands (CWs) are widely used around the world with various substrates, the mechanisms of how these modified substrates affect wastepan class="Chemical">water treatment are still unknown. In this study, CW microcosms were established with and without ceramsite as a substrate, and the wastepan class="Chemical">water treatment efficiencies were evaluated during 71 days of incubation. Using the 16S rRNA high-through sequencing, the mechanisms of how CW substrate changed the microbial community was quantified. The results showed that compared to soil as substrate, the use of ceramsite as substrate material enhanced the removal of pollutants from CW systems, particularly under a short retention time (1.5-day) condition. There were more beneficial microorganism groups (nitrogen, sulfur, phosphate) in the ceramsite CW system than the non-ceramsite CW system, particularly in the bottom layers. Moreover, the CW with ceramsite substrate had more nitrification function. All of these results suggested that the ceramsite CW system enhanced the removal of pollutants because it increased the concentration of key microbes that are necessarily for nutrient cycles.