Water lifting aerators control algal growth in drinking water reservoirs: Performance, mechanism and application

Artificial mixing has gained extensive attention owing to its strong applicability and effective inhibition of algae. However, few studies have explored the mechanisms by which water lifting aerators (WLAs) control algae growth. Here, a laboratory simulation of vertical light and temperature conditions in a reservoir was conducted to explore the mechanisms affecting algal growth. The mechanism of artificial mixing in controlling algae growth was investigated in situ. The results revealed that algal cell growth was inhibited under low temperature (15 °C, 5 °C) and lightless (0 lx) conditions, leading to suppressed synthesis of Chlorophylla and carotenoids, as well as reduced photosynthetic activity. Soluble microbial products content remained largely unchanged, whereas soluble protein content increased. After artificial mixing, nutrient and pollutant concentrations in the water, as well as algae density, were significantly reduced, and changes in algal community structure were observed. The interspecific relationships among the algae were primarily mutualistic symbiosis, which weakened at the action point after artificial mixing. Phosphorus (p < 0.05) and carbon (p < 0.05) contents significantly influenced algae community structure at the action point, with carbon (p < 0.05) content being a significant factor affecting algae abundance. The results provide a solid theoretical foundation for exploring the mechanism by which artificial mixing inhibits algae growth and proliferation, and offer scientific support for applying WLAs to control algae growth in drinking water reservoirs.