Distribution of polycyclic aromatic hydrocarbons in coke plant wastewater

Abstract

The subject of examinations presented in this paper is the distribution of polycyclic aromatic hydrocarbons (PAHs) between solid and liquid phases in samples of raw wastewater and wastewater after treatment. The content of 16 PAHs according to the US EPA was determined in the samples of coke plant wastewater from the Zdzieszowice Coke Plant, Poland. The samples contained raw wastewater, wastewater after physico-chemical treatment as well as after biological treatment. The ΣPHA16 content varied between 255.050 μg L−1 and 311.907 μg L−1 in raw wastewater and between 0.940 and 4.465 μg L−1 in wastewater after full treatment. Investigation of the distribution of PAHs showed that 71–84% of these compounds is adsorbed on the surface of suspended solids and 16–29% is dissolved in water. Distribution of individual PAHs and ΣPHA16 between solid phase and liquid phase was described with the use of statistically significant, linear equations. The calculated values of the partitioning coefficient Kp changed from 0.99 to 7.90 for naphthalene in samples containing mineral-organic suspension and acenaphthylene in samples with biological activated sludge, respectively.