A UNIQUE APPROACH TO SULFIDE MODELING FOR LOW FLOWS

The Elsinore Valley Municipal Water District's Washington Avenue Lift Station, proposed for future (calendar year 2008) construction is located in a service area that is rapidly growing. Though the lift station will be designed to handle an average buildout flow of 1.17 million gallons per day (mgd), the average daily flow at inception is expected to be 0.16 mgd. The vast difference between inception and buildout flows will lead to long force main detention time at inception with increased sulfide generation.In order to better estimate liquid-phase sulfide concentrations through a 24-hour period, a diurnal wastewater flow profile was “synthesized” and used for determining detention time of individual “volume groups” as they progressed through the force main. The detention times were then used for estimating sulfide generation in each volume group and constructing a diurnal sulfide concentration profile. The information from the modeling effort was ultimately used for evaluating and selecting a suitable sulfide and odor control system for the lift station.