The ability to remove the priority PAHs from water during coagulation process including risk assessment

The aim of the study was to determine extent, in which coagulation can affect to the risk reduction of human exposure to the consumption of water containing polycyclic aromatic hydrocarbons (PAHs). The paper presents results of research on the removal of priority PAHs (naphthalene, anthracene, fluoranthene, benzo(a)pyrene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(g,h,i)perylene, and indeno(1,2,3-cd)pyrene) from water in the volumetric coagulation and sedimentation process. For analysis were chosen coagulants such as aluminum(VI)sulfate and two pre-hydrolyzed coagulants—PAX XL 19H and FLOKOR 1ASW/B. Water samples subjected to coagulation were collected from selected water treatment plant following the pre-ozonation process. Tested coagulants were dosed at optimal doses (2.8; 3.6 mg Al3+/L). Summary concentration of eight hazardous PAHs in water after pre-ozonation amounted to 60.78 ng/L. After volumetric coagulation using selected coagulants was in the range of 31.51–33.64 ng/L. The highest efficiency in the removal of 8 PAHs was obtained after application of FLOKOR 1 ASW/B (48.2%). Also in the removal of benzo(a)pyrene FLOKOR 1ASW/B was the most effective (decrease by 89.9%). The risk analysis was carried out for five hydrocarbons: benzo(a)pyrene, benzo(b)fluoranthene and benzo(k)fluoranthene, benzo(g,h,i)perylene and indeno(1,2,3-cd)pyrene.