Study on PAHs in Composts of Municipal Sludge and Maize Straw

Co-composting of municipal sludge and maize straw by natural aeration was carried out and polynuclear aromatic hydrocarbons (PAHs) in compost were determined by GC/MS. The content of PAHs in compost was low, ΣPAHs and ΣPAHs_carc are 0.561 mg/kg and 0.107 mg/kg respectively and most of compounds are lower than 0.050 mg/kg. Predominant compounds were those with low-medium molecular weights. Significant degradation rate of PAHs in compost was found, ΣPAHs and ΣPAHs_carc are 80% or so and most of compounds are more than 50%. Greater degradation was observed for those compounds with medium molecular weights and 3-,4-benzene rings. Concentration, distribution pattern, and degradation rate of PAHs in compost depended to a great extent on the PAHs features in noncomposting municipal sludge.