Odors escaping from the City’s sewer system have been a source of complaints for many years.  A study, conducted by Boyle Engineering in 2003, identified the primary source of odor as hydrogen sulfide gas which occurs naturally in wastewater collection systems.  Gases escape from the collection systems and are malodorous, corrosive to equipment, and can be noxious in high concentrations.  Until 2005, the Wastewater Division had been using various chemical treatments to assist with reducing odors.  Conventional chemical treatment had limited effect.  To improve the City’s system, staff completed a detailed analysis of chemical and air scrubber technologies.  The conclusions led staff to seek and identify a new alternative technology.  Subsequently, the City Council supported the installation of the equipment in the Bluebird SOCWA lift station.
SuperOxygenation Equipment – The new technology is referred to as SuperOxygenation developed by Eco Oxygen Technologies, LLC (or ECO2).  ECO2 has completed installation of the odor reduction equipment at the Bluebird SOCWA lift station.  To quantify the results, the hydrogen sulfide gases along the southern end of the North Coast Interceptor have been measured since June 2006.  The air-release valve vault, located on Coast Highway adjacent to the crosswalk at Resort Drive, has been one of the points of measurement.  This location has been the primary source of a long history of odor complaints in the area between Ruby’s and the Albertson’s shopping area.
Odor Reduction Results – The initial measurements of hydrogen sulfide gas in the underground vault were measured to be peaking at an extraordinary 743 parts per million.  For perspective, in a confined space work environment, 20 parts per million is the safe limit of exposure for trained workers.  Within a few hours of start-up, the SuperOxygenation system dropped the gas levels down between zero and 5 parts per million.  The odors have been very nearly eliminated.  The equipment installation has been highly successful.