Development of an H₂S emission model for wastewater treatment plants

Modeling and prediction of H₂S emission from wastewater are important since gaseous H₂S will induce significant corrosion and odor problems. Most previous studies focused on H₂S emission of wastewater in pipeline systems, which may not be fit for H₂S emission in wastewater treatment plants (WWTPs). This study provided a two-phase mass transfer model for prediction of H₂S emission concentrations. The model is based on the mass transfer rate equation of the mass transfer impetus, expressed by the concentration difference. The main parameters of the model are the mass transfer coefficient, the carrier gas flow rate and the concentration of H₂S in liquid phase. The results showed that the model can simulate and predict H₂S emission concentrations of various processes in WWTPs. Moreover, the model can analyze and predict the influences of different pH values, mass transfer coefficients and carrier gas flow rates on H₂S emission concentrations and loads. Therefore, the model provides theoretical guidance for design of WWTPs regarding H₂S emissions.Implications: Modeling and prediction of H₂S emission from wastewater are quite important since gaseous H₂S will induce significant corrosion and odor problems. Most of previous studies are focused on H₂S emission from wastewater in pipeline system, which may not be fit for H₂S emission in wastewater treatment plants (WWTPs). Thus in this study, a model for predicting H₂S emission from typical units of WWTPs is established and verified. Moreover, the influences of pH values, mass transfer coefficients and carrier gas flow rates on H₂S emission are analyzed. The model can be a useful tool to predict the H₂S concentration in odor gas collection system of WWTP and understand the behaviors of H₂S emission under different WWTPs operating conditions.