SWWTP Post Aeration Diffuser Replacement

CIP# 650354-100000

The disinfection process at the Southerly Wastewater Treatment Plant (SWWTP) uses four (4) chlorine contact basins to disinfect the plant effluent and provide dissolved oxygen to the effluent through post aeration diffusers. The four tanks treat & disinfect all of the plant effluent that is produced & treated through the biological portion of the plant. The existing post aeration system includes four (4) grids of air diffusers (1 per tank) and 5 centrifugal blowers.

Due to UV exposure and age of the PVC pipe, several of the diffuser legs have broken. During repairs, Plant Maintenance staff noted that replacement parts were no longer available for the diffusers. This project will replace the existing diffuser grids with new ceramic disc diffusers and upgrade the diffuser legs with stainless steel piping to prevent future failures within the grid. As part of the upgrade, two (2) new rotary screw blowers (hybrid blowers) will replace two (2) of the centrifugal blowers that are reaching the end of their useful life. Two (2) of the other centrifugal blowers will be rebuilt to extend the useful life. Finally, the four (4) tank isolation butterfly gates will be replaced, as these are approaching the end of their useful lives. 

Construction is scheduled to begin in the fall of 2022 and will last approximately two (2) years. The construction will be sequenced to maintain at least three disinfection tanks in service to maintain the treatment capacity of the plant. 

Financing for this contract is being provided through a below market-rate loan through the OEPA’s Water Pollution Control Loan Fund (WPCLF) Program.

For questions about this project please contact Tyler Schweinfurth at 614-645-7758 or via e-mail at:  GTSchweinfurth@columbus.gov.