| Urban lakes replenished by reclaimed water have a reduced landscape function due to the high nutrient content of the water body and susceptibility to surface pollution. One reclaimed water replenished lake in the Yangtze River protection area was taken as a case, with closed- and open-water body areas for the control experiments. Transparency (SD), chlorophyll a (Chl-a), and turbidity (NTU) under different imported material ratios and dosages were analyzed. Therefore, an economically effective management plan was proposed. The results showed that visible pollution of the lake was serious. The imported material with 10% AC and 90% VZ had the best performance, for which, SD had been improved by more than 12%, NTU decreased by 28.14%, and Chl-a content reduced by 30.84%. Low doses (10~25) g/m3 of the composite material could rapidly enhance the visible appearance of the lake, whereas, high doses (50g/m3) may induce short-term fluctuations of NTU. However, it demonstrated a significant long-term effect on Chl-a removal, achieving more than 40% reduction compared to the control case. It is recommended to utilize a material combination of 10% AC+90% VZ, with cost of 0.2~0.4 RMB/m3, which is significantly lower than the costs associated with sediment removal and other methods. The research provides valuable insights for managing visible water pollution in lakes and similar water bodies replenished with reclaimed water. |
