The objectives of this study are to clarify the fate of phosphorus in coagulation/sedimentation process, and to determine the effects of phosphorus addition in biological activated carbon treatment on the biodegradability of organic substances and on the number and growth of attached bacteria.
The following conclusions can be made from this study: 1) The phosphorus concentration in supernatant after coagulation was 0.002 - 0.004 mg.l^-1 in water containing phosphorus of 0.063 mg.l^-1 or less. The phosphorus left in supernatant after coagulation was less than 0.011 mg.l^-1 even in water containing initial phosphorus concentration of 0.213 mg.l^-1. 2) Growth of attached bacteria and biodegradation activity on biological activated carbon were greatly affected by phosphorus.