Biosludge can be reused as an adsorbent after ZnCl2 activation, pyrolysis, washing with HCl and distilled water, and drying. But the pyrolysis exhaust of ZnCl2 immersed sludge can be hazardous to human health and the environment. The chemical composition, including carbon, nitrogen, hydrogen, sulfur and 21 trace elements, as well as the physical characteristics, including specific surface area, pore volume, pore size distribution and pore diameter of pyrolytic residue, were investigated in this work. In addition, the components of pyrolytic exhaust including 30 VOC species and 5 odorous sulfur gases were determined to evaluate the exhaust characteristics. The results indicated that the pyrolytic temperature was higher than 500 degrees C, the specific surface area could be over 900 m(2)/g, and the total pore volume could be up to 0.8 cm(3)/g at 600 degrees C. Exhaust concentration fractions of VOC groups were about 65-71% oxygenated VOCs, 18-21% chlorinated VOCs, 4-6% aromatic VOCs, and 6-10% acrylonitrile and cyclohexane under the specific conditions in this study. (C) 2012 Elsevier B.V. All rights reserved.