The application of Polyaluminium Ferric Chloride for Turbidity and Color Removal from Low to Medium Turbid Water

Background & Aims of the Study: Coagulation is an essential process for the removal offine particulate matter in water treatment. Polyaluminium ferric chloride (PAFC) is acomposite inorganic polymer of Aluminium and ferric salt. This study was conducted tofind out the optimum coagulation conditions for the removal of turbidity, color and organicmatter (UV absorbance) in low to medium turbid water.Materials & Methods: For evaluation of the coagulation procedure, conventional Jar Testapparatus was used. Low to medium synthetic turbid water (10 to 60 NTU) was preparedby kaolin and river bed soli. Then all samples were analyzed for residual turbidity, truecolor, UV absorbance, residual Aluminium (Al3+), Iron (Fe2+), and residual heavy metalslike Arsenic, Lead, Nickel and Chromium.Results: Optimum dose of PAFC for first, second, third and fourth sample with initialturbidity of 10, 20, 40 and 60 NTU was 7, 10, 11 and 11 mg/L respectively. Aftercoagulation with optimum dose, residual turbidity in treated water was 0.4, 0.34, 0.28 and0.3 NTU respectively. Also color removal efficiency for mentioned samples was 97%,98%, 99% and 99% respectively at optimum dose PAFC. Optimum pH for maximumremoval with PAFC was 7.8 (pH range 7.5 to 8).Conclusions: Polyaluminium ferric chloride has a good efficiency for removal of turbidity,color and organic matter. It can be select as a new coagulant for water treatment plants.Also residual Aluminium, Iron and some heavy metals (chromium, lead, cadmium andnickel) in treated water was investigated. Their concentration in treated water didn’t haveany adverse effect on consumer health according to their standards in EPA.