A critical review of artificial destratification systems for mitigating water stratification

Abstract

Thermal stratification (ThS) in water bodies, particularly during warmer seasons, severely degrades water quality by reducing oxygen levels, leading to detrimental ecological impacts. Artificial destratification technologies have emerged as potential solutions to mitigate these effects and improve water quality. This systematic review examines 194 studies from databases such as Web of Science, Scopus, MDPI, and ASCE, covering research from 1990 to 2024. The review evaluates various destratification methods, including mechanical mixers, bubble aerators, floating intakes, suspended curtains, multi-level offtakes (MLOs), and gradual entrainment level inverters (GELs), for their effectiveness in improving oxygenation and reducing nutrient buildup. It highlights that bubble aerators perform best in smaller water bodies, while mechanical mixers, though less common, offer cost-effective solutions for larger systems. However, mixers alone show limited effectiveness in large reservoirs, and their combination with bubble aerators can enhance system performance at increased operational costs. This review fills a critical gap in the literature by synthesizing available data on destratification technologies and their role in restoring ecological balance in stratified waters. The findings provide valuable insights for improving water pollution control strategies, supporting ecosystem health, and guiding future research and policy development to address the real-world challenges posed by ThS.