Effects of temperature and ph on the physical properties of activated sludge flocs

Physical properties of activated sludge flocs, especially settling and dewatering properties, are very important for efficient and economical treatment of wastewaters in activated sludge systems. The physiological and biochemical nature of activated sludge flocs and hence the settling and dewatering properties are greatly affected by the temperature and pH of the aeration basin. Therefore, in this study the effects of temperature and pH on the physical properties (settleability, filterability and compressibility) of activated sludge were investigated. From the results it was observed that, as the operating temperatures of the reactors were increased, zone settling velocities decreased, whereas sludge volume indices and specific resistance to filtration values increased. Up to 25°C sludges showed low compressibilities. However, they became highly compressible by the increase in temperature after 25°C. On the other hand, with the increase of the pH of the reactor zone settling velocities, specific resistanc...