Assessment of Odor Emissions at a Municipal WWTP in the Middle East

摘要

Dispersion models are often used to estimate the impact of odor emissions from unit processes at municipal wastewater treatment plants (WWTP) at the fence line of the property. The typical approach is to assess the emission rates from the various odor sources, and then perform air dispersion modeling to determine the expected odor concentration at the fence line. If the odor concentration at the fence line meets the WWTP's treatment objective, then no further treatment is required. However, if it does not meet the fence line odor objective, then the various odor sources are isolated and treated until the desired fence line odor concentrations are being met. This methodology works well for existing WWTPs, but it becomes challenging when a greenfield WWTP is designed, since no actual odor emission data is available for use in the dispersion model. This paper reports emission data estimations on a greenfield WWTP plant in the Middle East (Plant) to assess the degree of treatment that is required to achieve the Plant's desired fence line odor objectives. Because odor emission data was not available for WWTPs in the Middle East, it created a substantial challenge to perform the dispersion modeling, and emission rates were assumed. After the Plant was constructed, actual emission rates from the entire Plant were measured and compared with the theoretical assumed values, to determine whether the odor capture and treatment methods used at the Plant were sufficient to meet its fence line odor requirements. A comprehensive odor emissions study was performed at the Plant with the following objectives: 1) Measure the emission rate of every unit process identified as an emission source during the design phase of the Plant 2) Compare the measured emission rates to the previously assumed emission rates The data collected during this study forms a valuable database for use with dispersion models for similar future greenfield WWTPs in the Middle Eastern region to ensure that acceptable fence line odor concentrations are achieved. This paper further highlights some of the challenges experienced during the performance of the odor study, and the practical methods developed to perform odor measurements.