Experimental and process design of a treatment system to remove Aluminium ions from lean sludge in an Egyptian water treatment plant

Abstract

Abstract Aluminium ions traces in drinking water were found in El Khanka Water Treatment plant in Egypt because of the lean sludge generated from Alum’s use in water treatment. This research studies using natural clay such as “bentonite” known as montmorillonite clay and combining bentonite – cationic polymer as coagulants to remove aluminium salts from lean sludge. Experimental studies were performed to determine the effect of adding bentonite on the removal of aluminium ions from lean sludge based on variation of pH. 98.8% removal of Al ions was achieved at pH 11, and 0.6 ppm concentration of bentonite in the sludge solution. Kinetic model of pseudo-second-order was found to be the best to describe the reaction and the rate constant of 11.922 mol.-1 s-1 was calculated. An industrial process was suggested to the removal of Aluminium ions and brief economic estimate of applying it in Egypt was prepared as well.