Thermal pyrolysis of pharmaceutical wastewater sludge, brown coal, and sludge-coal blends were studied by TG dynamic runs carried out at 20 degrees C min(-1) in the temperature range from 25 to 850 degrees C. Different possible kinetic models of thermal decomposition have been considered. The best models of mechanism function for brown coal, pharmaceutical wastewater sludge, and coal-sludge blends are a first-order reaction, a N-dimensional nucleation, and growth reactions with N = 2 and 4, respectively. The Arrhenius kinetic parameters for brown coal, pharmaceutical wastewater sludge, and coal-sludge blends are proposed.