The City of Omaha, Nebraska has experienced significant odors from its Ohern Street grit basin which removes grit from wastewater influent at the Missouri River Wastewater Treatment Plant. WLA was contracted to research and identify alternatives for covering the grit basin. Due to the complexities of the clam shell structural steel, many traditional cover systems were eliminated from consideration. The new cover system was required by the City of Omaha to accommodate the existing clam shell grit removal process, be fully retractable by cables and winches without significant manual cover opening, and be constructed of compatible materials for the severe wastewater environment.
A Technical Memorandum was prepared that addressed various design issues and established requirements for this project. Working with a cover manufacturer, WLA prepared a cover system design that will cover the grit basin and meet City requirements. In addition to the cover system, an odor control unit was designed that generates a hydroxyl ion fog to oxidize hydrogen sulfide and eliminate related odors. A weatherproof enclosure was also designed to house the odor control unit and distribution piping of the fog to the grit basin. WLA prepared drawings and specifications that will be used to construct the cover system and other facility improvements.