Combined Application of Compound Algicide and Submerged Plants for Algal Bloom Control and Eutrophic Water Remediation
Eutrophication and cyanobacterial blooms threaten aquatic ecosystems and drinking water safety globally. This study evaluated the efficacy of a compound algicide (PQGA-126, PAC, and red soil) combined with submerged plants (Vallisneria natans and Hydrilla verticillata) for suppressing blooms and restoring eutrophic water. Indoor static experiments used algae-laden water from Nanhu Lake, Gongqingcheng, Jiangxi. Six treatments were established: control, V. natans alone, H. verticillata alone, algicide alone, algicide + V. natans, and algicide + H. verticillata. Results demonstrated that combined treatments significantly reduced total nitrogen (TN), total phosphorus (TP), chlorophyll-a (Chl-a), and turbidity, markedly lowering eutrophication within a short period. The combined approach outperformed single-plant treatments, with algicide + V. natans achieving the greatest reduction in the comprehensive trophic state index. Additionally, the algicide significantly enhanced V. natans growth rate and H. verticillata catalase (CAT) activity, indicating species-specific physiological responses. These findings suggest that integrating compound algicide with submerged plants, particularly V. natans, offers a promising strategy for rapid and effective eutrophic water remediation.