Selection of Coagulants for the Removal of Chosen PAH from Drinking Water

Abstract

The aim of the research was to determine the efficiency of a coagulation process with powdered activated carbon for the removal from surface water of benzo(a)pyrene and 16 polycyclic aromatic hydrocarbons (PAHs), including the sum of four standardized in the Council Directive 98/83/EC on the quality of water intended for human consumption: benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(g,h,i)perylene, and indeno(1,2,3-cd)pyrene. For the study, surface water was used, whose composition was modified with standard solution PAH MIX A. In the first stage, for water modified with standard PAH mixture, the coagulation process was conducted. As the coagulants Al₂(SO₄)₃·18H₂O, hydrolysed salts, and polyaluminum chlorides (PAX1910 and PAX19F) were used. In the second stage, the adsorption process was conducted. Powdered activated carbon was used (CWZ-22 and CWZ-30). In the third stage, the coagulation process and the adsorption process were combined. The best effects for the reduction concentrations of the sum of four normalized PAHs, as well as of benzo(a)pyrene, were obtained by applying coagulation carried out with PAX19F and aided by powdered activated carbon CWZ-30. The removal efficiency for these compounds was, respectively, 93.8% and 95.8%.