Use of Potassium Permanganate in Water Treatment

This article discusses a situation that occurred in May 1961 when the threshold odors on the Cedar River in Iowa reached 400 for the first time and a highly objectionable taste was present. The tremendous flood on the Cedar River in March of that year could have affected the odor and taste problem which developed. By the end of May, algae concentrations rose to about 18,000 organisms per milliliter. The most successful treatment consisted of adding permanganate at the intake, and permitting it to pass through the primary mixers and clarifiers without adding other chemicals. Alum coagulant was applied in the secondary mixers along with lime for pH adjustment. Carbon was added as the water passed out of the mixers and entered the final clarifiers. The ammonia and chlorine application point was changed to the clear well after filtration, and the permanganate dosage was adjusted so that the permanganate demand of the lime and coagulant dispelled the remaining color before addition of the carbon.