Treatment of raw water using bentonite clay as a coagulant aid

Abstract

The effectiveness of bentonite as a coagulant aid using PAC as a coagulant for raw water treatment was assessed in this study. The possible the conventional link between aluminum based coagulants has become an issue in water treatment. A method for treating water using a natural approach as an alternate to achieve enhanced coagulation might help to reduce risk to health, and be more environmentally friendly. Many water treatment plants use a combination of coagulation, sedimentation, filtration and disinfection to provide clean safe drinking water to the public. The study also was designed to compare the treatment costs of using Bentonite clay and polymer combination and polymer only in provision of safe drinking water. A series of batch coagulation tests were conducted by jar test to obtain the optimum dosage, pH, ratio of coagulant aid and primary coagulant, and for the jar test by efficiency evaluating the standard parameters, such as turbidity, pH, color, chlorine demand. In terms of these parameters, bentonite showed the best result, with a ratio of 30:70 in an optimal concentration of 1,000 mg/l with 0.15 ml PAC plus 0.35 g bentonite. The coagulants performed with an optimal pH of 5, with 30 min of mixing time during flocculation. However, the optimal pH. Condition during the jar test showed an improvement in the water alkalinity results, from pH 5 to 6.8. Coagulation with bentonite-chitosan successfully removed the turbidity with a highest Chlorine efficiency demand calculations of on polymer98%. Only and polymer and bentonite combinations, showed a higher chlorine demand when only polymer as used and comparatively lower chlorine demand when polymer-bentonite combination. This means less chemical to be used in treating water when bentonite is used. The study recommends that the Government should encourage the mining and manufacturing of Bentonite clay locally so as to subsidize on the cost of conventional water treatment and the time taken in treating water. In so doing less chemicals are used. To NW&SC they should find means of incorporating Bentonite clay in the water treatment process.