In September 2022, the Metropolitan Sewer District of Greater Cincinnati (MSDGC) issued a Request for Qualifications (RFQ) for the Mill Creek Wastewater Treatment Plant (MCWWTP) High-Rate Treatment Pump Station (MCPS) Progressive Design-Build Project. This marked the first step in a two-phase best value procurement process for which the Ulliman Schutte/Burgess & Niple (B&N) team was selected.
B&N’s extensive experience at the MSDGC Mill Creek Wastewater Treatment Plant is unmatched. Since 1989, B&N has designed and overseen the construction of 60 projects at the facility, ranging from architectural buildings to the more recent MCWWTP Diversion Chamber project, where B&N served as the design lead under design-builder Ulliman Schutte.
The Ulliman Schutte/B&N team brings in-depth knowledge of the MCPS site and the surrounding area. As part of a subcontract with Ulliman Schutte, B&N is the Engineer of Record, taking full responsibility for project design and related services, including alternative analyses, conceptual and detailed design, permitting and engineering support during construction.
The current facility consists of influent pumping stations (north and south) with a combined permitted capacity of 430 million gallons per day (MGD). However, these pump stations are aging and face significant operational, maintenance and reliability challenges. A 2019 hydraulic modeling report projected that, following improvements to the upstream conveyance system, the MCWWTP could face unrestricted peak flows of up to 700 MGD during a typical year, in alignment with the Wet Weather Improvements Plan (WWIP) objectives. While the facility can handle secondary treatment up to 300 MGD for short durations, expanding primary treatment, grit removal and secondary treatment to meet the 700 MGD requirement is not feasible due to site constraints. The recommended solution includes developing a future 400 MGD High-Rate Treatment (HRT) system, with up to 300 MGD directed to the MCWWTP, and the remainder sent to the HRT. The HRT will be designed and constructed as part of a future project.
Design and construction of the new screening facility and influent pump station required to convey flow to the MCWWTP and future HRT are at the heart of the current project. The project aims to achieve the following objectives:
- Increase screening and pumping capacity to 700 MGD (firm), including electrical upgrades.
- Construct a pump station with solids-handling pumps and twin trench-style, self-cleaning wet wells that can be independently isolated for maintenance.
- Install four bar screens in channels connected to the existing 10-ft-wide diversion chamber openings. This will allow for the isolation of individual screens for maintenance while maintaining the 700 MGD firm capacity.
- Implement an odor control system at the headworks.
- Split influent flow between the existing WWTP and a future HRT facility across Gest Street, with flow metering at both locations.
- Demolish existing structures in the project area to make way for new facilities.
- Provide a new 300 MGD plant disinfection system to meet E. coli permit requirements.
- Utilize the existing outfall to maintain current discharge capacity, considering limitations related to Ohio River elevations.
- Minimize service disruptions when relocating communication infrastructure, plant generators, document storage and utilities.
Given the proximity of the new construction to the existing north and south pump stations at the Mill Creek facility, it was crucial to maintain precise representations of the existing infrastructure. B&N initiated the design process with a geolocated scan using the RTC360 laser scanner. This data, combined with multiple technologies and data sources, including Cincinnati Area Geographical System (CAGIS) information, record drawings, Revit models, Cloudworx and geoBIM, provided a comprehensive visual representation of both aboveground and underground conditions.
The project team, including representatives from MSDGC (with Black and Veatch and Brown and Caldwell as Owners Agents), Ulliman Schutte and B&N, as well as major sub-consultant Hazen, visited the University of Dayton's Virtual Lab. The team utilized Revit-designed models to "walk through" the facility, noting details crucial for future design, maintenance and layout considerations.
The project is expected to be 100% design complete by February 2026. At that time, early work package construction will be complete and the main work package construction will begin.