Effect of Dissolved Oxygen on Microbial Population and Settling of Dairy Activated Sludge

The study was carried out to identify and study the settling characteristics of the dairy activated sludge. The causes and the control measure for the sludge bulking were studied. The activated sludge was generated by running a batch reactor of capacity of 10 liters for a θC of 10 days. It was operated until steady state conditions were reached. pH, DO, MLSS and COD were taken as the parameters. The settling studies were carried out for different MLSS concentrations ranging from 2g/L to 20g/L. The addition of Chlorine was selected as the control measure and was added for various doses such as 1 ml, 2 ml and 3 ml of Bleaching powder solution (1 ml of Bleaching powder solution contains 0.515 mg of Chlorine). Settling curves between interface height and time were observed before and after the addition of the Chlorine. From the settling curve the limiting solids flux were obtained. After the addition of Chlorine, there was a considerable increase in the settling velocity that improves the settling nature of the sludge. Area of Secondary settling tank was calculated from the modified solids flux method.