Occurrence and emission of polycyclic aromatic hydrocarbons from water treatment plant sludge in Taiwan

The concentrations level and distribution of 16 US EPA polycyclic aromatic hydrocarbon (PAHs) from the water treatment plant (WTP), sewage treatment plant (STP), and industrial water treatment plant (ITP) sludge in Taiwan were determined and then assessed the sources, and potential toxicity (carcinogenic polycyclic aromatic hydrocarbons [CPAHs] and toxic BaP equivalent [TEQ]). Results indicated that the total concentrations of PAHs ranged between 58 and 16,436 mu g/kg dw. Among the 17 samples, the 2-4 ring of total PAHs were the predominant compound in three kinds of treatment plant (> 60%). Especially, ITP1 owns 95.8% of 2-4 ring of total PAHs and ITP3 owns 54% of five- and six-ring of total PAHs. The molecular indices and principal component analysis (PCA) were used to determine the source contributions, with the results showing that the contributions of combustion/grass, coal or wood combustion and combustion/liquid (oil) fossil fuel combustion. A PAH toxicity indicated by TEQ was 2.5-506 mu g TEQ/g dw. Although, the results indicated that these were not recommended for land applications, but analyses are beneficial to develop effective management strategies for controlling PAH discharge in treatment plants and establishing strategies for its reuse in managing pollutants. [GRAPHICS] .

Automated summary

This study investigated the concentrations and distribution of 16 US EPA polycyclic aromatic hydrocarbons (PAHs) in water treatment plants, sewage treatment plants, and industrial water treatment plant sludge in Taiwan. The results revealed the presence of these compounds, with 2-4 ring PAHs being the predominant compounds. The study also assessed the contributions from different sources and evaluated the toxicity levels.