Evaluation of Sodium Aluminate as a Coagulant for Cost Savings at Water Treatment Plants

摘要

The feasibility of using liquid sodium aluminate (SA) in a more cost effective way for maintaining or improving the finished water quality at water treatment plants was studied. Evaluation of all tests performed, together with calculations of theoretical and actual values provide indications that SA will perform well and provide substantial advantages over present treatment. Tests conclude by adding approximately 24 mg/L of alum and discontinuing the feeding of caustic soda the following occurred: (a) 70% decrease in the actual amount of sodium added to the water while maintaining necessary levels of pH; (b) Reduction in chemical treatment cost of $27,000 per year for an average 6 MGD plant, also, providing the same process performance during clarification and filtration; (c) Reduced generation of sludge from the water treatment plant; (d) Water quality continued to be as is now attained, with the possible exception of color, which may increase slightly. SA is being successfully used in both conventional coagulation-sedimentation plants and an innovative coagulation-flotation plant.