Study on character of contamination in sewage sludge of south Tai lake drainage area

Heavy metals and polycyclic aromatic hydrocarbons in sludges of six wastewater treatment plants in south Tai lake area, China, were investigated in this research. The main objectives of the survey were to obtain basic data on the contaminant character and to assess the potential of sludge land application. Concentrations of heavy metal in most of sludges were below the regulatory limits for the sludge to be used in agriculture in China. All 16 PAHs, targeted by the USEPA agency, were found in most of the six sludges. Individual PAH content varies considerably with sewage samples. The ratios of concentration suggest that petroleum and combustion of fossil fuel were the dominant contributions for the PAHs in sewage sludge. Results of benzo(a) pyrene carcinogenicity equivalent value (BaPeq) analysis indicated that Benzo(a) pyrene and Dibenz (a,h) anthracene were the main contributer of carcinogen. It is, therefore, essential to pay much attention to the change and transference of these two kind contaminants during the sludges disposal course.