Kingsley Wastewater Treatment Plant
Kingsley, IA | Public Works
ISG designed the retrofit of existing wastewater treatment lagoons for the City of Kingsley, enabling more compliant and higher capacity wastewater treatment processes.
Anticipating growth over a 20-year planning period and with its wastewater treatment facilities no longer able to keep up with local standards, the City of Kingsley needed a water solutions partner to design system updates.
The City of Kingsley’s existing continuous discharge aerated lagoon was not capable of meeting NPDES effluent limits after changes were made to Iowa’s water quality standards. Following a detailed alternatives analysis, ISG recommended retrofitting the existing wastewater treatment lagoons using a Submerged Attached Growth Reactor (SAGR). The SAGR is primarily designed to provide nitrification (ammonia removal) in cold to moderate climates. The SAGR consists of a submerged gravel bed with evenly distributed wastewater flow across the width of the cell providing the necessary surface area for growth and attachment of a nitrifying biomass within the bed. The gravel bed is covered with a layer of peat or mulch for insulation. Aeration throughout the floor of the SAGR provides aerobic conditions that are required for nitrification. An effluent ultraviolet disinfection system also allows the City to meet more stringent bacterial limits during summer months.
Since the Iowa Wastewater Facilities Design Standards did not specifically address the SAGR type process, the Iowa DNR had to perform a technology analysis in order for Kingsley to proceed with the project. Based on the IDNR review, the SAGR system was approved as an acceptable alternative technology, and the City of Kingsley proceeded with one of the first installations in Iowa using the SAGR technology.