Mathematical Modeling of Drying Characteristics of Sewage Sludge

Drying characteristics of sewage sludge were investigated using hot air of a temperature range of 50~80degC and an air velocity range of 0.60~1.48 m/s at a laboratory scale dryer. Several mathematical models available in the literatures were fitted to the experimental data by multiple nonlinear regression analysis. Four statistical parameters: coefficient of determination (R²), reduced chi-square (chi²), root mean square error (RMSE) and mean relative deviation modulus (P) were used to evaluate the fitting of these models to experimental data. The Page model gave the better predictions than others. Then a modified model based on Page model was developed and the new model could fit the drying characteristics of sewage sludge well with R² over 0.9993 at widely drying conditions.