Abstract
Excessive growth of filamentous organisms has been reported that it was a cause of sludge bulking in activated sludge system for wastewater treatment and had various living factors in many sides of biological engineering fields and operating fields. In this laboratory scale study, each substrate composition in two kinds of synthetic wastewater was settled, and the ways of water feed into the aeration tanks were practiced in order to find growth and control factors of filamentous organisms. The following aspects could be obtained from the experiment. 1) The SV values (y, ml) and MLSS values (x, g) were observed with time in various modified activated sludge processes. Rearranging these results, the relation was obtained as y=ax+b, a value means average SVI value in each experimental period in about ten days. It was apparent that a value was highest (max, 755ml/g) in the extended aeration process with continuous feed of No. 1 synthetic nutrient water. 2) SVI values showed the tendency to be higher in under 0.06 of F/M value (food to microorganism ratio). 3) The multiple regression analysis was practiced between F/M value and the time to bulking occurrence in various substrates feeding methods to each aeration tank.
