Occurrence and removal of polycyclic aromatic hydrocarbons in the wastewater treatment process

• Published in: Ecotoxicology and environmental safety Vol. 82; pp. 1 - 7
• Main Authors: Tian, Weijun, Bai, Jie, Liu, Kunkun, Sun, Huimei, Zhao, Yangguo
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 01.08.2012; Elsevier
• Subjects: Accounting; Animal, plant and microbial ecology; Applied ecology; Applied sciences; Biological; Biological and medical sciences; biological treatment; China; cities; Distribution; Ecotoxicology, biological effects of pollution; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; General aspects; molecular weight; Pollution; Polyallylamine hydrochloride; Polycyclic aromatic hydrocarbons; Polycyclic Aromatic Hydrocarbons - analysis; Polycyclic Aromatic Hydrocarbons - chemistry; seasonal variation; Seasonal variations; Seasons; Sewage - analysis; Sewage sludge; Sewage treatment plant; Sludge; sorption; Waste water; Waste Water - analysis; Waste Water - chemistry; Wastewater; Wastewater treatment; Wastewaters; Water Pollutants, Chemical - analysis; Water Pollutants, Chemical - chemistry; Water Purification - standards; Water treatment and pollution; China, People's Rep; Polycyclic aromatic hydrocarbons; Wastewater; Sewage sludge; Sewage treatment plant; Distribution; Ecotoxicology; Hydrocarbon; Toxicity; Polycyclic aromatic compound; Waste water; Persistent organic pollutant; Pollution; Environment; Waste water purification; Organic compounds
• ISSN: 0147-6513; 1090-2414
• DOI: 10.1016/j.ecoenv.2012.04.020

The occurrence and removal of polycyclic aromatic hydrocarbons (PAHs) was examined at different stages at a modified anaerobic-anoxic-oxic biological wastewater treatment plant in Tai’an City in eastern China. Twelve PAHs were detectable, with low molecular weight PAHs found at different treatment stages in wastewater and sludge. The most frequent and abundant PAHs in the influents were different in May and November. In May, 3- and 4-ringed PAH compounds were predominant, accounting for 53.5% of the ∑PAHs. However, in November, 2-ringed PAH compounds were most frequent and abundant, accounting for 90.1% of the ∑PAHs. In May and November, the removal efficiencies of individual PAH compounds ranged from 72.4 to 99.4% and from 21.1% to 100%, respectively, in the total treatment process. A significant relationship was observed between the removal efficiency and log Kow of the PAH compounds in the grit stage (when the values of log Kow were higher than approximately 5), suggesting that these compounds were principally removed through sorption to sludge particles and transfer to sludge processing systems. The residence time impacted the removal efficiency in the biological treatment process at the primary and secondary stages. In addition, the removal efficiencies depended dramatically on seasonal variations. ► Fate of 16 PAHs in a modified anaerobic-anoxic-oxic treatment process. ► The partition of PAHs between wastewater and sludge. ► Removal mechanisms of PAHs on various treatment steps. ► Impacts of season change on PAHs distribution and removal efficiencies.