The efficiency of four different composting processes to bioremediate polycyclic aromatic hydrocarbons (PAHs)-contaminated sewage sludge was investigated. Prior to composting, sewage sludge coming from the Datansha wastewater treatment plant, Guangzhou, China, was mixed with rice straw to obtain a C/N ratio of 13: 1. After 56 days of composting, the total concentrations of 16 PAHs (Sigma(PAHs)) ranged from 1.8 to 10.2 mg kg(-1) dry weight, decreasing in order of inoculated-manual turned compost (IMTC) > manual turned compost (MTC) > continuous aerated compost (CAC) > intermittent aerated compost (IAC), exhibiting removal rates of 64%, 70%, 85% and 94%, respectively. Individual PAHs were generally removed in similar rates. IAC treatment showed a higher removal rate of high molecular weight PAHs and carcinogenic PAHs comparing to the other composting processes. (c) 2006 Elsevier B.V. All rights reserved.