Odor Reduction in a Wastewater Treatment Plant Using Potassium Permanganate

Odor is currently one of the most common problems facing wastewater treatment plants. Hydrogen sulfide (H2S) is a toxic, flammable gas that is often the cause of the odors. The pungent odor associated with hydrogen sulfide can result in neighborhood complaints. Potassium permanganate (KMnO4) was recently used during a plant trial to reduce the odor at a wastewater treatment plant in a southeastern United States community. The plant currently treats an average of 160 MGD of raw wastewater. A plant survey and trial were conducted to determine the origin of the hydrogen sulfide gas and the amount of permanganate required for oxidation. The highest level of hydrogen sulfide recorded within the plant was 815 ppm above the belt presses. After the addition of potassium permanganate the hydrogen sulfide levels above the belt presses were reduced from 815 to 0 ppm, and subsequent measurements continued to show low hydrogen sulfide levels. The filtrate from the belt presses was also analyzed and found to have a dissolved hydrogen sulfide concentration of approximately 5 mg/L; this was reduced to 0 mg/L after the application of permanganate. Therefore, the use of permanganate for reducing hydrogen sulfide levels during the plant trial was deemed successful.