MULTI-SYSTEM ODOR CONTROL FOR 10 MGD PUMP STATION AND 5-MILE FORCE MAIN

The development of a large-scale planned community requires infrastructure to serve all present and future phases of the area planned for development. When wastewater collection and conveyance facilities for a planned community are financed through a Utility Local Improvement District (ULID), the facilities must be constructed to serve the population growth projected for the entire 20-year bond period.The planned community of Northwest Landing contains 500 acres of property within the City of DuPont that is zoned for residential, commercial, industrial and mixed use. The conveyance system that transports wastewater flows generated by the Northwest Landing community was funded by ULID and constructed in 2001. The system conveys wastewater over five miles, discharging to the existing Pierce County collection system located in a highly urbanized area with several restaurants directly adjacent to the point of discharge. The system was put on line with wastewater flows ranging from 150,000 to 200,000 gallons per day at the start up, which will then increase to a peak flow of 10 million gallons per day (MGD) at the end of the 20 year build out period.The ULID funding required the construction of a pump station, force mains and gravity sewers to handle this wide range of flow, including odor control facilities that would control odor emissions at the point of discharge after 36 hours of detention time in the force main.