Obnoxious odors from Wastewater Treatment Plants (WWTPs) have been of concern for many years. Recently there has been a greater social focus on odor related problems due to strict air quality regulations and increasing public concern with health and environmental deterioration [9]. Generally, odor emissions from WWTPs are from both point and area sources and are characterized by low concentrations and high air volumes over large areas. To determine the odor emission rate, knowledge of the flow rate and corresponding odor concentration are required. Usually large open area sources are significant contributors to overall odor emissions at WWTPs [10]. When measuring emissions from area sources, an enclosure device (flux chamber) is commonly employed to sample gaseous emissions from a defined surface area of the source.

This involves determining the concentration of volatile compounds under a special cover in which aerodynamics and flow rates are controlled. The emission rate is expressed as the product of this concentration and flow rate.Various types of reduced sulfur and nitrogen compounds behave as the key components of odor (and nuisance) [2, 9, 11]. Therefore, a precise description of the gas composition from Wastewater Treatment Plants (WWTPs) can be highly valuable in assessing the environmental impact of malodor issues in both the WWTPs and its surrounding areas [12-14]. This study has been initiated to explore the emission characteristics of Reduced Sulfur Compounds – hydrogen sulfide (H2S), methyl mercaptan (CH3SH), dimethyl sulfide ((CH3)2S), dimethyl disulfide ((CH3)2S2) – ammonia (NH3), and trimethyl amine ((CH3)3N) from a typical medium-sized Wastewater Treatment Plant (WWTP) in Korea.

Table 1 presents the selected odorous compounds and their corresponding odor threshold values associated with Batimastat domestic wastewater.Table 1.Selected Odorous Compounds from Wastewater Treatment Plant and their Corresponding Odor Threshold values.The odor threshold refers to the minimum concentration required for an individual to perceive the odor, although the exact type of odor may not be identifiable [2]. A Wastewater Treatment Plant (WWTP), located at Sun-Cheon, Chonlanam-Do was chosen as the test facility (Figure 1). It was chosen as it represents a typical medium sized WWTPs in Korea.

It employs the activated sludge treatment process, which is the most common treatment process for the Korean wastewater treatment plant.Figure 1.Location of Sun-Cheon Wastewater Treatment Plant.In this study, emission characteristics of six selected odorous compounds from a WWTPs were investigated. Also, this study evaluated flux profiles of the six selected odorous compounds emitted from the water surface of the WWTP using a Dynamic Flux Chamber (DFC) which is found to be a suitable sampling device for area sources such as wastewater treatment plants.