Enhancing the coagulation process performance by using kaolin and bentonite Iraqi clays as coagulant aids: Experimental study

This research focused on the use of bentonite and kaolin clay as auxiliary materials for alum in coagulation. Experiments were conducted on a laboratory scale, and to represent the process of coagulation, flocculation, and sedimentation, a Jar test device used experiments were conducted on Synthetic prepared turbid water using calcium carbonate of two levels of turbidity are 100 NTU and 600 NTU. First, the best doses were determined for the three materials, and then the best medium was determined to achieve the best removal by pH control from 5.3 to 9.8 the use of turbidity removal as a reference for the best removal after determining the best dose of materials and the best medium to achieve the best removal, use five levels between alum and bentonite clay for the two levels of turbidity and the same for kaolin clay, In an acidic medium. and the results were the best removal to turbidity with 600 NTU (0% bentonite : 100% alum ) 99.57% when use only alum (40 mg/l), (75% kaolin : 25% alum ) 99.78% when use (41.25 mg/l of kaolin and 10 mg/l of alum ) and the best removal to turbidity with 100 NTU (50% bentonite : 50% alum ) 98.58 % when use (5mg/l of bentonite and 10 mg/l of alum), (40% kaolin : 60% alum ) 97.06 % when use (10 mg/l of kaolin and 12 mg/l of alum ). After the treatment, the sludge was taken into the samples that achieved the best removal and was divided into three sections once used directly and again for regeneration using a base solution once and an acid solution for different periods. The best removal of turbidity was achieved when the sludge was immersed for two hours in an acid solution. the removal percentage are (88.75, 96.26, 90.59, 96.67). Experiments have shown that bentonite and kaolin clay are effective in the removal of turbidity Whether used alone or with alum