عنوان مقاله [English]
Coagulation and flocculation are the principal units in water treatment processes. In this study, the Jar test was used to investigate the effects of the pH and TOC on FeCl3 and PACl coagulants for further removal of turbidity, organic matter, aluminum, total organic carbon (TOC), dissolved organic carbon (DOC), organic Aadsorption at a wavelength of 254 nm (UV254 nm ), alkalinity, residual aluminum and ferric, total trihalomethans (TTHMs) in the Karaj River in the year 2007- 2008. These experiments were conducted through a bench scale study using conventional coagulation in the influent to Tehran Water Treatment Plant No. 2 (TWTP2).With normal pH levels, PACl demonstrated more efficiency than FeCl3 in removing turbidity, TOC, UV254 nm, and TTHMs. The lower coagulant consumption, high floc size, lower floc detention time, lower sludge production, lack of the need for pH adjustment in turbidity of 25 NTU and the lower alum consumption were the advantages of PACl application instead of FeCl3 as a coagulant. Also, PACl application was efficient at low turbidity (2 NTU), average turbidity (6 NTU), and high turbidity (100 NTU) in TOC, turbidity, UV254 nm , and DOC removal. Thus, PACl is an economical alternative as a coagulant in TWTP2.