Removal of harmful cyanobacterial blooms in Taihu Lake using local soils. III. Factors affecting the removal efficiency and an in situ field experiment using chitosan-modified local soils.
Effects of ionic strength, pH, organic content, cell concentration, and growth phase on the removal of MA cells using chitosan-modified sepiolite were studied in the laboratory. The MA removal efficiency increased with the increase of salinity for normal clay flocculation. In contrast, for chitosan-modified clays/soils, MA removal efficiency increased with the decrease of salinity. The removal efficiency of chitosan-modified sepiolite was not significantly affected by pH (6-9), but dropped dramatically beyond pH 10. Humic acid had a small negative effect on the removal of MA cells. Cells were removed more effectively by clays around the early senescence growth phase than other growth stages. The removal efficiency increased as the cell concentration increased. In a field enclosure of Taihu Lake, a loading of 0.025 g/L chitosan-modified local soils removed 99% algal cells and no increase of chlorophyll-a was observed during the following one month's monitoring process.
Pan
Gang
G
State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. gpan@mail.rcees.ac.cn
Zou
Hua
H
Chen
Hao
H
Yuan
Xianzheng
X
D000538:Aluminum Silicates; D000863:Antacids; D002452:Cell Count; D002614:Chelating Agents / Q000494:pharmacology*; D002681:China; D048271:Chitosan / Q000494:pharmacology*; D000077215:Clay; D000458:Cyanobacteria; D056890:Eukaryota / Q000254:growth & development; D005068:Eutrophication; D005427:Flocculation; D005618:Fresh Water / Q000382:microbiology*; D006812:Humic Substances / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D017633:Magnesium Silicates; D009994:Osmolar Concentration; D012965:Sodium Chloride; D012987:Soil
D000538:Aluminum Silicates; D000863:Antacids; D002614:Chelating Agents; D006812:Humic Substances; D017633:Magnesium Silicates; D012987:Soil; D012965:Sodium Chloride; D048271:Chitosan; C001671:magnesium trisilicate; D000077215:Clay