Inactivation and Removal Technologies for Algal-Bloom Control: Advances and Challenges

The aim of this review is to summarize the inactivation and removal technologies used for algal-bloom control and to serve the development of theories and technologies for algal bloom prevention and control in the future. The efficiency of inactivation and removal of algal blooms largely depends on the density of bloom-forming microalgae faced when the control measures are adopted. Locally enhanced electric field treatment technology has shown the most potential for low-density algal-bloom control, which could effectively inactivate algal cells with low energy consumption. Magnetic capture technology has outstanding advantages for the separation and capture of high-density algae blooms owing to its high efficiency, easy separation, and low cost. This article reviews the physical, chemical, physicochemical, biological, and ecological methods of algal-bloom prevention and control. The key to effective prevention of algal blooms is to select the appropriate method based on the difference in microalgae density. For example, under low-density stages, if the inactivation of algae cells can be realized, the occurrence and development of high-density algal blooms may be prevented, and under high-density stages, if the capture of algae cells can be done effectively, the subsequent environmental hazards brought by algal blooms will be reduced or even eliminated. This paper will help in choosing appropriate methods of algal-bloom prevention and control based on the difference in microalgae density and providing suggestions for future research on algal-bloom control.