Feasibility study of vertical flow constructed wetland for tertiary treatment of nanosilver wastewater and temporal-spatial distribution of pollutants and microbial community. (1st September 2019)

• Record Type: Journal Article
• Authors: Huang, Juan; Yan, Chunni; Liu, Jialiang; Guan, Wenzhu; Singh, Rajendra Prasad; Cao, Chong; Xiao, Jun
• Is Part Of: Journal of environmental management. Volume 245(2019)
• Page Start: 28
• Page End: 36
• Publication Date: 2019-09-01
• Subjects: Silver nanoparticles -- Vertical flow constructed wetland -- Tertiary treatment -- Temporal-spatial distribution -- Microbial community; Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2019.04.128
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: Silver nanoparticles (AgNPs) have the potential to cause negative effects on nutrient removal in constructed wetlands (CWs), further leading to the deterioration of the water. The current work aimed to investigate the feasibility of vertical flow CW (VFCW) for tertiary treatment of AgNPs wastewater, temporal-spatial distribution of pollutants, and microbial community after 450-day exposure. Results reveal that the effluent of VFCW could still meet the discharge limits except the slightly excessive concentration of phosphorus (>0.5 mg/L) from day 390, with the average removal efficiencies of 83%, 61%, 42%, 70%, and 66% for the chemical oxygen demand, total nitrogen, ammonia nitrogen, total phosphorus, and soluble orthophosphate during 450 days, respectively. Results show that AgNPs removal was relatively stable over time, up to 96%. The temporal-spatial analysis reveals that all contaminants were mainly retained in the soil layer. The Ag concentrations in the upper soil layer and plant roots were higher than that in the lower soil layer and plant stems and leaves, respectively. Microbial sequencing analysis reveals the significant differences in the microbial community at different depths on day 450, with the dominant phyla of Proteobacteria, Acidobacteria, Chloroflexi and Bacteroidetes, and dominant genera of Halomonas and Pseudomonas . These results provide much needed knowledge for the implementation of ecological technologies for AgNPs and nutrient removal simultaneously. Highlights: VFCW exposed to AgNPs achieved the discharge limits for COD and N removal. The P concentration in the effluent was above 0.5 mg/L from day 390. VFCW with I. pseudacorus could remove AgNPs effectively, with soil as main sink. Microbial community structure at different depths showed the significant difference.