The role of tropical cyclones in stimulating cyanobacterial (Microcystis spp.) blooms in hypertrophic Lake Taihu, China

Performance Evaluation of Constructed Wetlands Treating Wastewater Treatment Plant Effluent in Taihu Lake, China

“…However, with the gradual reduction in pollutants, the microbial community structure presented some differences. The removal of NH 4 þ -N in the tail water occurred at the front part of the ecological ditch, while the www.advancedsciencenews.com www.clean-journal.com TN removal mainly occurred at the back end of the ecological ditch and in the ecological pond section. This is because the denitrifying bacteria (DGGE profiles showed the presence of M. opportunistum and P. denitrificans in winter [Supporting Information Figure S1] and M. opportunistum in summer [Supporting Information Figure S2]), which were mainly located at the back end of the ecological ditch, played an important role in TN removal.…”

“…[14] Meanwhile, as the microorganisms growing in deeper water are less affected by temperature changes, the microbial community diversity of horizontal subsurface flow was significantly higher, when compared with that of the surface flow in winter (Supporting Information Tables S6 and S7), and accordingly, the COD and NH 4 þ -N removal efficiencies of the horizontal subsurface flow were also higher (17.7% and 18.5%, respectively). In summer, the difference in the microbial community diversity in the horizontal subsurface flow and surface flow was less, illustrating that the diversity of microorganisms directly influenced the pollutant removal efficiency and that the trend of influence of biodiversity and effluent COD concentration on the process ranking was the same.…”

“…With regard to surface-flow wetlands, owing to the enrichment of many denitrifying bacterial populations such as Pseudomonas putida and Acidovorax avenae, the TN removal rate was higher (up to 32.4% in summer, Supporting Information Figure S4 and Table S7). The 1 year water quality monitoring of vertical-flow wetland-ecological pond-surface-flow wetland-horizontal-flow wetland process showed that the inlet COD concentration of the combined wetland system was higher and the influent NH 4 þ -N, TN, and TP concentrations were lower in summer, when compared with those in winter, which may be related to the different wastewater compositions. Furthermore, the COD and NH 4 þ -N removal rates declined in summer, when compared with those in winter.…”

“…Chemical oxygen demand (COD), NH 4 þ -N, total nitrogen (TN), and total phosphorus (TP) were determined according to standard methods. [19] …”

“…blooms since the mid-1990s. [4][5][6][7] Evidence of parallel changes in the availability of nutrients during tropical cyclones, which is considered as a key factor promoting specific cyclone-induced algal blooms, has not been well documented. [8,9] Besides the high percentage of ammonia nitrogen (NH 4 þ -N) in the major rivers draining into Taihu Lake, it has been reported that unreasonable industrial structure and layout, high percentage of secondary industries, and in particular, excessive pollutants in the wastewater treatment plants (WWTPs) effluent have resulted in serious pollution in the river branches, poor quality of the lake water, and heavy N and P pollution in the Taihu area.…”