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Client:
City of Orange City, IA

Orange City, IA

Key Features:

  • New flow-through sequencing batch reactor (SBR) wastewater treatment facility
  • Preliminary treatment includes spiral screening and grit removal
  • UV disinfection

Key Experience:

Wastewater Treatment Facility (SBR)

DGR Engineering (DGR) worked with the City to evaluate alternatives, which included constructing a sequencing batch reactor (SBR), mixed bed biofilm reactor (MBBR), retention and land application, activated sludge, or submerged attached growth reactor (SAGR). The evaluation considered capital costs, long-term operation and maintenance costs, operational flexibility and expandability. After consideration and numerous site visits, the City ultimately determined a flow-through style SBR system to be the preferred choice based on the selection criteria and the ability to meet anticipated permit limits.

Preliminary treatment includes a spiral screen and vortex grit removal system. The three-unit SBR follows the pre-treatment equipment. The combination of aeration on/off as well as mixing allows the facility to reach very low levels of ammonia, total nitrogen and phosphorous. An ultraviolet (UV) disinfection system follows the SBR units and was included to meet effluent disinfection requirements. A full-plant supervisory control and data acquisition (SCADA) system was incorporated in the project for remote monitoring.

The new system will utilize two existing lagoon cells for flow equalization and sludge storage prior to land application. During peak flow events, the facility can split flow to utilize the dedicated lagoon for equalization and then route influent wastewater back through the plant when flows subside. The facility was designed to treat a total flow of 2.45 million gallons per day (MGD) to accommodate projected 20-year domestic and industrial growth. The improvements made the facility easily expandable for future needs and was designed with impending nutrient limits in mind.

Total project cost was $9.9 Million. The City used local bonds for the project costs.