Measurement, control, and modeling of H₂S emissions from a sewage treatment plant

Hydrogen sulfide is reported as one of the most common odor-producing compounds from sewage treatment plants. The literature review revealed that very little information is available on the emission of H₂S from different units of sewage treatment plants. Besides, the removal efficiency as well as dispersion studies of H₂S should be explored more. Therefore, the purposes of this study were to measure the emissions of H₂S, evaluate the efficiency of odor control unit, and explore the dispersion potential of H₂S from a sewage treatment plant in Muscat, Sultanate of Oman. Site survey analysis revealed four sources (tanker discharge area, grit/sand and fog removal channels, pre-aeration basin, and screen building) of H₂S in the plant premises. Additionally, measurement analysis showed that the efficiency of odor control unit, which treated the emissions from all sources, except the tanker discharge facility, was 90.2%. The Gaussian plume dispersion modeling studies demonstrated that the allowable concentration of dispersed H₂S (1 ppm) was observed > 30 m from the identified sources. Although the combined outlet of the odor control unit was greater than 1 ppm, the plant is complying with the current environmental specifications at the boundaries (≤ 1 ppm) set by the environmental authorities. Hence, a set of recommendations is suggested to improve the efficiency of the system to resolve the odor emission from the plant.