Partnering together, Dowl HKM Engineering and Pioneer designed a Butte-Silver Bow sewer collection system to collect and convey sewage from the TIFID Industrial Park near Silver Bow, Montana, to the Butte-Silver Bow Metro Sewer Wastewater Treatment Plant in Butte. The system is comprised of 21,000 feet of gravity main, 33,000 feet of 14-inch diameter force main, and 2 lift stations. Because the alignment of the force main crosses interstates, busy roads and intersections, rivers and creeks, a variety of construction techniques and materials have been evaluated to determine the most feasible and cost-effective method of installation, including trenchless technologies (specifically directional drilling and bore-and-jack) and utilizing a variety of different pipe materials including polyvinyl chloride (PVC), fusible PVC, and high density polyethylene (HDPE).
To avoid expensive upgrades to the system as the industrial park grows, the entire system, including the 2 lift stations, has been sized to accommodate the range from current to 20-year projected sewage flow requirements. To collect information for the anticipated construction conditions along the route, Pioneer completed a geotechnical survey for the construction of the lift stations and installation of the gravity and force main sewer. This investigation has identified two locations that, due to groundwater conditions, would have been difficult to construct with traditional construction methods.
In order to promote the seamless progression of construction activities, every landowner along the project alignment has been identified, as well as any associated easement and/or permit needs. The compiled permits required for this project include joint applications (124, 404, and nationwide permits), Montana Department of Transportation utility occupancy permits, railroad permits from Burlington Northern Santa Fe (BNSF) railroad and Union Pacific (UP) railway, and a Montana Department of Environmental Quality storm water discharge permit. Pioneer has led the permitting effort for the project.