Water Service - U.S. Water Services
Church Street CSO Reduction Project - Phase 1
| Client: | Sanitation District No.1 of Northern Kentucky (SD1) |
| Location: | Taylor Mill, KY |
| Budget: | $70,000 |
| Challenge: | Balancing the effectiveness of alternatives for the entire collection system, opposed to just the project area scope |
The Sanitation District No. 1 of Northern Kentucky (SD1) is developing solutions for reducing or eliminating overflows from its sewer systems. The Church Street sub-basin was selected as a priority area for alternative development. The Church Street Priority Area includes three Combined Sewer Overflows (CSOs) and two active sanitary sewer overflows (SSOs) along Banklick Creek near its confluence with the Licking River. The focus of this project was on the area contributing to the Church Street CSO, which is roughly 152 acres of mostly residential area. The flow from the Church Street sewershed is conveyed via a 36-inch and a 48-inch interceptor. The two interceptors are badly damaged and contain several inlets which drain a low-lying area that is proposed to become a biofiltration basin. The Church Street CSO reduction project was split into two phases, Phase 1 is composed of the 50 acres located south of 43rd Street.
XCG was responsible for modeling the Church Street combined sewer area using the InfoWorks CS modeling software. The first task of this project was to review the existing conditions model provided as part of the Sanitation District’s System Wide Model (SWM). XCG used flow monitoring data to adjust model parameters to make the model more intuitive and user-friendly for SD1 to use in the future. The end result was a calibrated model suitable for analyzing various alternatives.
The preferred alternative for the Church Street CSO Reduction Project had four main components: a new 72-inch interceptor, a biofiltration basin, private source and street load removal of runoff, and a new CSO regulator. The replacement of the 36-inch and 48-inch interceptors with a new 72-inch interceptor will be essential in removing the inlets located along the two existing interceptors and removing I/I due to damaged pipes. The biofiltration basin was sized to be able to treat the runoff generated by the first 0.8-inches of runoff, assuming both Phase 1 and Phase 2 will be completed. Several options were discussed for street load separation and private source disconnects, with a focus on gallons of CSO (also cost/gallon) removed during the Typical Year. A new CSO regulator structure was proposed to maximize storage in the 72-inch interceptor, as well as to provide control of solids and floatables from discharging to the Banklick Creek. While the focus of this project was on the Church Street CSO basin, consideration was given to preventing adverse impacts to the other two CSOs and SSOs in the surrounding areas. As a result, the height of the overflow weir went through several iterations, and some additional work was proposed outside the Church Street CSO area to eliminate one of the adjacent existing SSO’s and to reduce the typical year overflow volume at another.
Modeling results indicate that Phase 1 of the Church Street CSO Reduction Project has the potential to reduce the Typical Year Overflow volume from 55 MG to 17 MG and reduce the number of CSO activations in the Typical Year from 76 to 32.
Geoff Edwards
Business Group Leader /
Associate
Contact Geoff for help with
your Municipal Infrastructure or U.S. Water Services related project.
513-841-9246
