Preparation and Usage of Polyaluminum Chloride as a Coagulating Agent

Abstract

Three different coagulating agents, Iraqi-produced alum, Swedish-produced alum, and laboratory- produced polyaluminum chloride (PAC) were used to clarify samples taken from Iraqi river water. A laboratory rig was built to produce PAC from the reaction between hydrochloric acid and aluminum powder. The results after raw water treatment showed that the dosage of PAC required for treatment was 98% less than that of alum when it was applied to water at a low turbidity and almost 90% less in the case of much higher turbidity. The application of PAC produced rapidly forming flocs and more compact sludge compared to that of alum. However, there were no significant changes in the pH of the solution. From the results obtained, the PAC agent performed better compared to alum and might be considered a good alternative to alum for raw water and waste water treatment.

Keywords

• alum, polyaluminum chloride, water treatment