The development and infringement of urban residential areas on potential malodor sources specifically wastewater treatment plants (WWTP) has led to an increasing number of public grievances against these malodorous compounds such as odorous compounds. Major sources of these compounds in WWTP are ammonia (NH3) and hydrogen sulfide (H2S). Various technologies have been proposed and applied for the treatment of malodorous components from contaminated air. Chemical scrubber (CS) is a well-known, widely established, and reliable technology. Accordingly, in this study a detailed Technical investigation of a CS as the most commonly employed odor control system in wastewater treatment plants (WWTPs) was conducted over a 45-day time period at a municipal WWTP. To this aim, CS odor control system was first designed and constructed and afterward, installed at the Yazd wastewater treatment plant in Iran. The assessment of emissions quantity indicated that odor emissions from the Yazd WWPT mainly consist of hydrogen sulfide (H2S) and ammonia (NH3). To technically assess, the effects of various parameters, including contaminated airflow rate and EBRT and also, oxidant nature and scrubbing flow rate for the wet scrubber, on simultaneously H2S and NH3 removal were investigated. The removal efficiencies of NH3 and H2S were found to be affected by their respective loading rate. Additionally, the NaOCl solution was shown to give the best results in terms of removal efficiency and compatibility among the various oxidants examined in the chemical scrubber. The experimental results showed that almost complete removal of NH3 was achieved and the H2S removal efficiency remained above 95% regardless of the operating conditions used. It clearly demonstrated the effectiveness of CS system in treating actual waste gases containing H2S and NH3.
