Effect of hydrodynamic condition on algae control based on montmorillonite modified lime-ceramic sand-lake sediments

Abstract

Montmorillonite modified lime-ceramic sand-lake sediment (LC-sediments) was synthesized and its algae removal efficiency was investigated in this study. Montmorillonite not only improved the morphology and surface area of original LC-sediments, but also promoted the algal removal rate due to its inherent properties such as accumulating an electric charge, acting as a flocculant, and displaying a local bridging effect. Based on parameter optimization including the ratio of raw materials, agent dosage, initial algae density, pH and a determination of overlying water, the effect of hydrodynamic conditions on the algal removal process was researched. Under the optimal condition, the removal rates of turbidity, algae density and chlorophyll a could reach 86, 88 and 68%, respectively. As verified with a response surface model, it was shown that low disturbance (stirring) of the algae could promote algal removal by montmorillonite modified LC-sediment. Furthermore, a water column was utilized to approximatively simulate the flocculation and algae control in shallow lakes. This study solved the problem of reducing the dosage of lake sediment and improving the removal efficiency of algae without causing secondary pollution to the environment. It was expected to provide a certain theoretical basis for clay flocculation-based algae control in a real environment. HIGHLIGHTS Hydrodynamic conditions on algal removal process were studied.; Montmorillonite improved algal control efficiency of modified lake sediment.; Water column was utilized to simulate the state of natural lakes.; The removal rates of turbidity and algae reached 86 and 88%, respectively.;

Keywords

• algae control
• hydrodynamic condition
• lake sediments
• montmorillonite