The City of Columbus embarked on a $2.5 billion plan to reduce combined sewage overflows throughout their collection system. A cornerstone of those plans was the construction of additional treatment capacity for wet weather flows at the Southerly Wastewater Treatment Plant. The chemically enhanced primary treatment (CEPT) facilities will increase the treatment capacity of the plant by 110 MGD, to a total of 440 MGD. Plant modifications made to increase its treatment capacity, including:
- Additional raw sewage pumps and influent screens
- New primary clarifiers and flow splitting
- New coagulation and flocculation chemical feed facilities
- New primary sludge pumping and gravity thickening facilities
- Upgrade of existing disinfection equipment and facilities
- New dechlorination equipment and facilities
Because the new CEPT facilities are only operated during large wet weather events, the facilities have been designed to be simple and flexible while minimizing maintenance effort. This presentation will provide an overview of the facility, the wet weather treatment start-up results, start-up lessons learned of a major treatment train that is dependent on weather, and ongoing operational improvements.
The initial wet weather treatment results presented will include the sampling plan parameters compared to regulatory limits. The start-up lessons learned will be captured from the management challenges of coordinating a multi-contract project to operational challenges of an intermittently run facility that is fully dependent on the weather. On-going operational improvements will be explained, such as improved automatic operations, chemical dosing, and sludge pumping.