Pyrolysis of activated sludge from sewage treatment was investigated in the presence and absence of silica and sand under varying conditions (temperature and retention time) in a fixed bed reactor. The presence of silica and sand had a significant impact on the amount of hydrogen and methane generated under the conditions studied, with both of these substances causing a significant reduction in hydrogen and methane yields compared to those obtained in the absence of these substances. The maximum yield of hydrogen was observed under the following conditions: no silica/sand, 1,073 K, 180 min. Maximum methane yield was observed to be under the following conditions: no silica/sand, 1,073 K, 180 min.