After the Iowa Department of Natural Resources (IDNR) issued the City of Brandon, Iowa, a National Pollutant Discharge Elimination System permit containing an Ammonia nitrogen and E. coli Compliance Schedule, they turned to Fehr Graham to ensure the plant was updated to meet limits while also maintaining affordable rates for citizens.
The Wastewater Treatment Plant (WWTP) violated ammonia and E. coli limits and needed a better removal and disinfection system. Our team designed improvements to update the lagoon cells that included removing sludge and liners, installing blowers and adding a diffused air system. Updates also included adding Submerged Attached Growth Reactor (SAGR) beds, a building containing an ultraviolet (UV) disinfection system, an effluent lift station, electrical upgrades and a standby power generator. The aerated lagoon WWTP was correctly sized for the flow and loading, so we reused the infrastructure with modifications, resulting in significant cost savings.
Our team identified an issue when we learned the proposed SAGR system would be in a regulated flood plain. The top of dikes on the aerated lagoon treatment plant were a few feet above the flood plain elevation, which meant adding SAGR cells and a UV disinfection system wouldn't allow effluent to flow by gravity to the stream during flooding. This could result in flooding of the UV system and overflow of wastewater from the SAGR cells. Our team designed an effluent lift station to be installed after the UV disinfection system. To save energy, effluent typically flows by gravity to the discharge point and the lift station pumps the effluent flow only when the stream is flooding.
With our help, the City secured funding to minimize rate increases. We worked closely with the Iowa Northland Regional Council of Governments who administrated the Community Development Block Grant (CDBG), and with the United States Department of Agriculture (USDA) who provided a loan and grant for the project. We also worked closely with the IDNR on wastewater and flood plain permitting.
We prepared plans and specifications for the project, prepared contract documents meeting the requirements of the funding sources, assisted the City in a bid letting, and provided construction engineering services, which included construction staking, observation, and administration. This project brought the WWTP back into compliance and improves water quality of the receiving stream.
AT A GLANCE
» Topographic survey.
» Funding assistance.
» Contract documents for funding sources.
» Engineering design.
» Plans and specifications preparation.
» Bid letting.
» Construction staking, observation and administration.