Abstract
Fifteen strains of floc-forming bacteria were isolated from river water. Strain No.4 was the best floc former and the ratio of flocculated cells to total cells was about 90%. According to scanning electon microscopy, cells in the floc were bridged and embedded in a mesh. The floc of this bacterium was partially deflocculated with actinase. In growth and floc-formation, the removal of COD and BOD in the supernatant were about 61% and 64%, respectively. Total phosphorus concentration in the supernatantdecreased to 66.5% of initial total phosphorus concentration in floc-forming phase and then gradually increased in flocculated phase.
