Review on the control of algal blooms via artificial mixing: theory, technologies and mechanism

Artificial mixing influences the algal growth and structure by regulating hydrodynamic conditions, which has been applied to control the algal blooms in the global lakes and reservoirs for many years. The related researches at home and abroad have been widely reported, but the systematic review is rare. Especially, due to the limited understanding of the application precondition, application conditions, and advantages and disadvantages of different technologies, these technologies were misused and did not play its advantages, which resulted in the poor and even ineffective effect on algal control. The main conclusions includes: (1) Artificial mixing controls the change of algal biomass and structure by regulating mixing depth (Zmix), whose application effect is mainly related to the water depth, horizontal distribution of mixing devices, system operation regimes, and mixing efficiency; (2) The algal control period (i.e., the reduction of more than 95% of algal cell density) of Artificial mixing is about 2weeks, and the recommended Zmix threshold for algal control is more than 15m; (3) Artificial mixing is mainly suitable for the deep waters, and the selection of algal control technologies should consider their application conditions, cost effectiveness and so on. © 2024 Chinese Society for Environmental Sciences. All rights reserved.