title: Identification and removal of polycyclic aromatic hydrocarbons in wastewater treatment processes from coke production plants.
abstract: Identification and removal of polycyclic aromatic hydrocarbons (PAHs) were investigated at two coke plants located in Shaoguan, Guangdong Province of China. Samples of raw coking wastewaters and wastewaters from subunits of a coke production plant were analyzed using gas chromatography-mass spectrometry (GC/MS) to provide a detailed chemical characterization of PAHs. The identification and characterization of PAH isomers was based on a positive match of mass spectral data of sample peaks with those for PAH isomers in mass spectra databases with electron impact ionization mass spectra and retention times of internal reference compounds. In total, 270 PAH compounds including numerous nitrogen, oxygen, and sulfur heteroatomic derivatives were positively identified for the first time. Quantitative analysis of target PAHs revealed that total PAH concentrations in coking wastewaters were in the range of 98.5 ± 8.9 to 216 ± 20.2 μg/L, with 3-4-ring PAHs as dominant compounds. Calculation of daily PAH output from four plant subunits indicated that PAHs in the coking wastewater came mainly from ammonia stripping wastewater. Coking wastewater treatment processes played an important role in removing PAHs in coking wastewater, successfully removing 92 % of the target compounds. However, 69 weakly polar compounds, including PAH isomers, were still discharged in the final effluent, producing 8.8 ± 2.7 to 31.9 ± 6.8 g/day of PAHs with potential toxicity to environmental waters. The study of coking wastewater herein proposed can be used to better predict improvement of coke production facilities and treatment conditions according to the identification and removal of PAHs in the coke plant as well as to assess risks associated with continuous discharge of these contaminants to receiving waters.
authors.affiliation: Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China.
authors.forename: Wanhui
authors.initials: W
authors.lastname: Zhang
authors.forename: Chaohai
authors.initials: C
authors.lastname: Wei
authors.forename: Bo
authors.initials: B
authors.lastname: Yan
authors.forename: Chunhua
authors.initials: C
authors.lastname: Feng
authors.forename: Guobao
authors.initials: G
authors.lastname: Zhao
authors.forename: Chong
authors.initials: C
authors.lastname: Lin
authors.forename: Mengyang
authors.initials: M
authors.lastname: Yuan
authors.forename: Chaofei
authors.initials: C
authors.lastname: Wu
authors.forename: Yuan
authors.initials: Y
authors.lastname: Ren
authors.forename: Yun
authors.initials: Y
authors.lastname: Hu
mesh_terms: D003077:Coke / Q000032:analysis*; D007221:Industry; D011084:Polycyclic Aromatic Hydrocarbons / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification
chemical_list: D003077:Coke; D011084:Polycyclic Aromatic Hydrocarbons; D014874:Water Pollutants, Chemical