A new drying kinetic model for sewage sludge drying in presence of CaO and NaClO

Drying kinetics behavior and energy parameters of untreated and chemically treated sludge were evaluated in this study. The fixed bed isothermal drying of sewage sludge was achieved by using lab scale hot air oven. The drying data were evaluated through various semi-theoretic drying models developed earlier and a new model with three constants based on the general solution of Fick's second law. The best fit models were evaluated through the coefficient of determination (R2), the sum of square error (SSE), root mean square error (RMSE) and chi-square (χ2) values. The results revealed that irrespective of chemical treatment the sludge drying was followed the new proposed model, and rate of drying increased while the time of drying decreased with the rise of temperature. The activation energy for drying for CaO treated sewage sludge was found to a minimum (19.83 kJ/mol) and NaClO treated sludge was recorded maximum (36.73 kJ/mol).