Lochmueller was selected to complete the remaining three projects of the City of Huntington’s (City) approved Long-Term Control Plan. This included a large interceptor project from the wastewater treatment plant (WWTP) to CSO 016 and adding disinfection to the existing CSO Retention Treatment Basin (RTB). The interceptor project addressed CSOs 003, 009, 010, 013, 014, & 016.
Due to the size and complexity of the project, the City wanted to keep the interceptor out of the downtown area to limit disruption to local businesses. During preliminary design, Lochmueller performed hydraulic modeling, running multiple scenarios to determine the viability of moving the interceptor north out of the downtown. After consideration of the data, it was decided that the interceptor would be moved north to Tipton Street, which not only would take it out of downtown, but would provide the opportunity to upgrade the pavement, curbing, and sidewalks along the route as well.
The interceptor was 36” on the upstream and 72” on the downstream, ranging in depth from 15’ to 35’ deep. Some challenges throughout the project included tunneling of the Norfolk Southern Railroad, sole access to the WWTP, and significant utility relocation. Once constructed, the interceptor sewer will transport flows up to, and including, the 10-year, 1-hour rain event volume to the WWTP where it will receive primary treatment and disinfection within the City’s recently upgraded RTB.
The project also included the construction of a new fiber optic line to most of the CSOs where new weir structures and check valves were installed. This fiber optic allows the City to eliminate the dependency on a third-party service to monitor the CSOs and allows for real-time data through the SCADA system.
At the treatment plant, converting the existing CSO tank to a RTB saved the City a significant amount of money compared to constructing a separate tank as a disinfection structure or to store the 10-year, 1-hour event. Project #9 constructed a new chemical feed building that provided sodium hypochlorite disinfection to the RTB and bisulfate to dechlorinate after the RTB.
