This project located in Denver, Colorado, improved nitrification and de-nitrification capabilities so Metro Wastewater Reclamation District could meet the stringent nitrate regulatory discharge criteria at the 100 MGD Robert W. Hite Facility. The $48 million project included the construction of four new centrate and return activated sludge re-aeration basins (CaRRB) and modifications to the existing influent channel, which treats centrate ammonia. The project also included the modifications to 12 of the existing aeration basins, replacement of 12 existing 120′ secondary clarifiers, including new return activated sludge pump stations, as well as the installation of mixed liquor return pumps. The 100 MGD facility remained in operation and within discharge requirements throughout construction. The project was sequenced such that the new CaRRB basins were built and started prior to making the modifications to the secondary clarifiers and aerations basins.
“After having worked an entire shift from midnight to 8:00 AM, Garney coordinated with Metro District personnel to mobilize large pumps at the headworks to divert flow around the Districts’s bar screen buildings. Your employees’ quick actions prevented what could have been a massive overflow of the North Plant influent.”
Catherine R. Gerali, District Manager for Metro Wastewater Reclamation District