Modeling Odors and Hydrogen Sulfide in the Sewers of San Francisco

A detailed measuring campaign targeted on hydrogen sulfide (H2S) was undertaken in the Bayside drainage area of San Francisco. The purpose was to assess whether a conceptual sewer process model could reproduce H2S concentrations and other wastewater characteristics to a level where it could be applied to further improve odor and H2S management. The campaign covered 12 locations in the drainage area and included measurements in the wastewater as well as the sewer atmosphere. The tested model was based on the WATS sewer process concept, which previously had yielded promising results for catchment scale modelling, but never been calibrated to such an extensive dataset. The study showed that the model was capable of reproducing the general levels of wastewater H2S concentrations, wastewater pH values, and sewer H2S gas levels. It could also reproduce the general variability of these parameters, albeit with some uncertainty. It was consequently concluded that the model could be applied for the purpose in mind.