期刊
SCIENCE OF THE TOTAL ENVIRONMENT
卷 867, 期 -, 页码 -出版社
ELSEVIER
DOI: 10.1016/j.scitotenv.2022.161259
关键词
Constructed wetland; Bauxite residue leachate; Microbial community; Phragmites australis
Constructed wetlands (CWs) have been proven to be a cost-effective alternative for treating mine waters. In this study, a pilot-scale wetland was implemented to treat alkaline bauxite residue leachate, and after 5.5 years of operation, the CW effectively reduced the influent pH from 11.5 to 7.8. Trace element analysis showed a significant reduction in Al, As, and V, with sediment analysis revealing an accumulation of elevated pH and trace element content in the first 5 meters of the wetland. The investigation into microbial communities highlighted the importance of further research in alkaline CWs.
Constructed wetlands (CWs) have been demonstrated as a cost-effective alternative to chemical treatment systems for mine waters, with the microbial communities attributed to promoting carbonation and aiding pH neutralization. However, few data are available for the long-term use of CWs treating alkaline leachates nor the activity of microbes within them. To in-vestigate the feasibility of CW to buffer alkaline pH, a pilot-scale wetland was implemented in 2015 to treat alkaline bauxite residue leachate. After 5.5 years, samples of supernatant water and sediment were taken at 0.5 m increments along the 11 m long wetland. Waters were analysed for pH, EC and metal(loid) content, while sediment was subjected to physico-chemical assessment and element fractionation. Microbial biomass and community were assessed by phospholipid fatty acid analysis (PLFA) and functionality by the Rapid Automated Bacterial Impedance Technique (RABIT). Evidence presented demonstrates that the CW operating for 66 months effectively treats bauxite residue leachate, with re-duced influent pH from 11.5 to 7.8. Trace element analysis revealed effective reduction in Al (94.9 %), As (86.7 %) and V (57.6 %) with substrate analysis revealing a frontloading of elevated pH and trace element content in the first 5 m of the wetland. Sediment Al, As and V were present mostly (>94 % of total) in recalcitrant forms. Sediment Na was mostly soluble (48-62 %), but soils were not sodic (ESP < 15 %). Investigations into the microbial community revealed greatest biomass was in the first 5 m of the wetland, where pH, EC and metal contents were greatest. Microbial respiration using endemic Phragmites australis as a substrate demonstrates an ability to cycle recalcitrant carbon sources within a CW system. These novel microbial findings highlight the need for further investigation into the microbial communities in alkaline CWs.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据