|
| Purification of cadmium-tungsten composite polluted simulated wastewater by a three-stage simulated constructed wetland |
| Received:November 02, 2022 Revised:March 09, 2023 |
| View Full Text View/Add Comment Download reader |
| KeyWord:simulated wetland;combined pollution;wastewater purifying;plant enrichment;sediment |
| Author Name | Affiliation | E-mail | | WU De | College of Environment and Ecology of Hunan Agricultural University, Changsha 410128, China
Hunan Engineering & Technology Research Center for Irrigation Water Purification, Changsha 410128, China
Key Laboratory of Southern Farmland Pollution Prevention and Control, Ministry of Agriculture and Rural Affairs, Changsha 410128, China | | | ZHANG Weiyu | College of Environment and Ecology of Hunan Agricultural University, Changsha 410128, China
Hunan Engineering & Technology Research Center for Irrigation Water Purification, Changsha 410128, China
Key Laboratory of Southern Farmland Pollution Prevention and Control, Ministry of Agriculture and Rural Affairs, Changsha 410128, China | | | LIU Yuling | College of Environment and Ecology of Hunan Agricultural University, Changsha 410128, China
Hunan Engineering & Technology Research Center for Irrigation Water Purification, Changsha 410128, China
Key Laboratory of Southern Farmland Pollution Prevention and Control, Ministry of Agriculture and Rural Affairs, Changsha 410128, China | | | YAO Junfan | College of Environment and Ecology of Hunan Agricultural University, Changsha 410128, China
Hunan Engineering & Technology Research Center for Irrigation Water Purification, Changsha 410128, China
Key Laboratory of Southern Farmland Pollution Prevention and Control, Ministry of Agriculture and Rural Affairs, Changsha 410128, China | | | ZHANG Puxin | College of Environment and Ecology of Hunan Agricultural University, Changsha 410128, China
Hunan Engineering & Technology Research Center for Irrigation Water Purification, Changsha 410128, China
Key Laboratory of Southern Farmland Pollution Prevention and Control, Ministry of Agriculture and Rural Affairs, Changsha 410128, China | | | PENG Ou | College of Environment and Ecology of Hunan Agricultural University, Changsha 410128, China
Hunan Engineering & Technology Research Center for Irrigation Water Purification, Changsha 410128, China
Key Laboratory of Southern Farmland Pollution Prevention and Control, Ministry of Agriculture and Rural Affairs, Changsha 410128, China | | | TIE Boqing | College of Environment and Ecology of Hunan Agricultural University, Changsha 410128, China
Hunan Engineering & Technology Research Center for Irrigation Water Purification, Changsha 410128, China
Key Laboratory of Southern Farmland Pollution Prevention and Control, Ministry of Agriculture and Rural Affairs, Changsha 410128, China | tiebq@qq.com |
|
| Hits: 1390 |
| Download times: 606 |
| Abstract: |
| To explore the purification effect and mechanism of a simulated constructed wetland on simulated cadmium-tungsten composite polluted wastewater under hydroponics conditions, a pre-experiment was conducted to select three common aquatic plants： Thalia dealbata Fraser, Cyperus alternifolius L. and Hydrocotyle vulgaris L. These plants were used to build a hydroponic model of a tertiary simulated constructed wetland. Three treatments were set up： single planting treatment（T1）, paired planting treatment（T2）, and three types of combined planting treatment（T3）. The dynamic experiment was carried out using simulated composite sewage with initial concentrations of 25 μg·L-1 and 75 μg·L-1 of cadmium and tungsten, respectively. The results showed that the average effluent cadmium concentrations in T1, T2, and T3 simulated constructed wetlands were 3.30, 3.20, and 2.75 μg·L-1, respectively. The average removal rates for cadmium were 87.01%, 87.41%, and 89.18%, respectively. The average effluent tungsten concentrations were 24.02, 20.14, and 26.75 μg·L-1, and the average removal rates were 68.24%, 73.36%, and 64.62%, respectively. The simulated constructed wetland system showed a good purification effect on the simulated wastewater. A total of 375 mg of cadmium was injected into T3 treatment, and 333.75 mg was retained by the system, of which 102.66 mg and 231.09 mg were retained by plant enrichment and sediment adsorption interception, respectively. Similarly, out of 1 125 mg of input tungsten, 723.75 mg was retained by the system interception, of which 375.02 mg and 348.73 mg were retained by plant enrichment and sediment adsorption interception, respectively. The enrichment effect of cadmium and tungsten in the three plants was good, and the enrichment concentration of the same plants decreased along the direction of the water outlet, namely, the first level wetland > the second level wetland > the third level wetland. The sediment had a high adsorption capacity for both heavy metals in the system. By scanning the morphology of the sediments under SEM and FTIR spectroscopy analysis, it was found that there was a large number of uneven adsorption sites on the sediment surface. The main adsorption functional groups were －OH, －COOH, C＝C, and C－O－C, which provided insight into the mechanism of sediment adsorption for cadmium and tungsten. The three-stage simulated constructed wetland showed a good purification effect for cadmium and tungsten in wastewater. This study provides technical support for the purification of cadmium and tungsten in polluted irrigation water in tungsten mining areas. |
|
|
|
