1990 Volume 26 Pages 19-29
A sequential batch reactor activated sludge system was operated on several feeding schedule using artificial wastewater made up of glucose and peptone and influence on sludge settleability of the loading rate which meant volumetric organic loading during the feeding period was examined. When the loading rate was low, Sphaerotilus natans grew predominantly. The polysaccharide storage capacities and carbohydrate metabolism rates were examined using the activated sludge capacity test. When the loading rate was low, filamentous bulking sludge which had the low polysaccharide storage capacity and the fast metabolism rate was produced. A simple kinetic model of storage and metabolism was developed to explain the growth of filamentous bacteria in the activated sludge. The kinetic model could express the activated sludge metabolism of carbohydrates in both the capacity test condition and the operating condition very well. Using the model, the competitive growth of floc forming bacteria and filamentous bacteria was calculated. It was suggested that at the high loading rate operation, floc forming bacteria which had high polysaccharide storage capacity became dominant, while at the low loading rate operation, filamentous bacteria which had the low polysaccharide storage capacity and the high metabolism rate could become dominant.
