INTERCEPTOR HYDROGEN SULFIDE GENERATION MODEL FOR PREDICTION OF CORROSIVE ENVIRONMENTS SACRAMENTO REGIONAL COUNTY SANITARY DISTRICT

A model to predict sulfide concentration levels within the Sacramento Regional County Sanitation District's (SCRSD) collection system was prepared by V&A Consulting Engineers, Inc. This study was performed in three phases. In Phase I atmospheric and wastewater samples were collected and tests were performed to gather baseline information pertaining to the level of dissolved sulfides within the studied interceptor system. In Phase II – a model was developed to predict sulfide concentrations at various points in the interceptor system and at the entrance to the treatment plant. Lastly, during Phase III follow up field observations were made at manhole locations that were predicted to be at risk of corrosion by the model.Based on the completion of these phases, it was found that the model generally represents sulfide levels in the interceptor system as of October 2005 and demonstrates the ability to dynamically predict sulfide generation within the tolerance of the predictive equations used in the model for the interceptor system. Model values were graphed on a surface plot to help visualize system “hot spots”, and to determine effective and optimal adjustments to the H2S reduction program.Future uses of the model can include updates to the model for each major upgrade to the system to determine the effect of changing flow conditions on sulfide generation within the system. Determination of more effective chemical dosing volumes/schedules, and causes of initial high levels of H2S on certain locations. It is also recommended that calibration and adjustment of the model be performed to further fine tune its accuracy.