[Removal of algae using local soils and sediments].

Removal of algal blooms using modified local soils and sediments was studied. It was found that the local soils and sediments modified by chitosan removed algae effectively. The component of local soils and sediments, the organic matter in local soils and sediments had no effect on algae removal. Organic matter content (TOC < or = 40 mg/L) in water had a little negative effect on removal of algal cells. Field experimental results suggested that chitosan-modified local soils could be highly effective and quick for emergency needs to clear up harmful cyanobacterial blooms in fresh waters. In enclosures in Meiliang Bay of Taihu Lake, a loading of 0.025 g/L or 53 g/m2 chitosan-modified local soils removed 98.6% chlorophyll-a while secchi depth increased from 15 cm to 90 cm.