Big River Wastewater Treatment Facility Regionalization

Jefferson County Public Sewer District

Horner & Shifrin assisted in the analysis and design for WWTF improvements.


H&S completed a feasibility study to seek funding for the $20 million dollar project.  The report included the construction of major plant improvements and line work improvements that would allow the Lower Big River Wastewater Treatment Facility (WWTF) to become a regional plant.  The improvements included in the plan will remove multiple upstream plants from operations.  In late 2020, funding was secured from USDA-Rural Development.  The feasibility study included estimating of capital costs, review of Operating and Maintenance scheduled, updates to Replacement schedules and ultimately a user charge review.

Phase 1 of the regionalization project will include the decommissioning of four existing direct discharging treatment facilities,  and construction of 2.6 miles of new sewer networks to connect numerous un-sewered homes to the Lower Big River WWTP. The existing Lower Big River WWTP will be upgraded with a new oxidation ditch treatment process designed to process 650,000 gpd, with future Phase 2 regionalization expansion to 1.0 MGD. The existing package plant treatment units at the Lower Big River WWTP will be refurbished to be utilized as aerobic digesters allowing for the WWTP to operate as a regional biosolids handling facility for the District. The WWTP upgrades will also include design and construction of a new elevated headworks with automatic fine screening and manual screen bypass, and a new UV disinfection system.

Additionally, Horner & Shifrin prepared topographic survey for 100’ wide corridors on approximately 18,000 lineal feet located in Jefferson County, Missouri in Byrnes Mill and House Springs to be utilized in the design of the new storm sewer system. Survey included deed and plat research on all properties adjoining the corridor. All improvements and utilities including but not limited to curbs, pavement, walks, buildings, sewers, trees, creek channels, and existing grades were located and an existing surface and 1-foot contours which were prepared in AutoCAD format.


Project Scope





Byrnes Mill, Missouri

Year Completed


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