This paper investigates sewage sludge disposal methods with particular emphasis on combustion as the
priority disposal method. Sewage sludge incineration is an attractive option because it minimizes odour,
significantly reduces the volume of the starting material and thermally destroys organic and toxic
components of the off pads. Additionally, it is possible that ashes could be used. Currently, as many as
11 plants use sewage sludge as fuel in Poland; thus, this technology must be further developed in
Poland while considering the benefits of co-combustion with other fuels.
This paper presents the results of experimental studies aimed at determining the mechanisms
(defining the fuel combustion region by studying the effects of process parameters, including the size
of the fuel sample, temperature in the combustion chamber and air velocity, on combustion) and kinetics
(measurement of fuel temperature and mass changes) of fuel combustion in an air stream under different
thermal conditions and flow rates. The combustion of the sludge samples during air flow between
temperatures of 800 and 900 C is a kinetic–diffusion process. This process determines the sample size,
temperature of its environment, and air velocity. The adopted process parameters, the time and ignition
temperature of the fuel by volatiles, combustion time of the volatiles, time to reach the maximum
temperature of the fuel surface, maximum temperature of the fuel surface, char combustion time, and
the total process time, had significant impacts.