AWWA JAW21576

Ferrous sulfate was studied as an alternative coagulant to ferric chloride. Coagulants were evaluated for iron content, heavy metal contaminants, acidity, chlorine demand, and settleable solids. Jar tests and split-plant trials demonstrated similar performance at comparable costs with either coagulant. An anomaly that was evident throughout the study was that a pound of iron in the form of ferrous sulfate was 20 percent more effective than iron as ferric chloride. An equation was developed to compare ferric chloride and ferrous sulfate on a cost and performance basis for subsequent bids. As a result of the increased competition in bidding, there was a 50 percent decrease in the cost of coagulant over a three-year period. Includes 8 references, tables, figures.