Development of an improved model for settling velocity and evaluation of the settleability characteristics.

The characterization of sludge settling is important in determining the operating performance of the secondary clarifier and also evaluating the purification efficiency of wastewater treatment plants. Many models have been proposed to explain the activities of settling velocity and illustrating the relationship between settleability characteristics. The aim of this research was to present a model for the settling velocity as a function of the stirred specific volume index at 3.5 g/L (SSVI ), based on the Vesilind function, the solids flux theory, and the experimental data. Using this model gives an important performance improvement after calibration of the different settleability parameters. PRACTITIONER POINTS: Batch settling tests are some of the most interesting source of information to determine the sedimentation velocities and their characteristics. The modeling as an optimum operation of wastewater treatment plants is widely used for design, optimization, and management of installations. The characterization of sludge settling is important in determining the operating performance of the secondary clarifier. The characterization of sludge settling is necessary to evaluate the purification efficiency of wastewater treatment plants.