Phase V West Ashley Sewer Tunnel and Influent Pump Station

Completed in 2020 by Oscar Renda Contracting, the Phase V West Ashley Sewer Tunnel and Influent Pump Station Project involved constructing a 60 MGD capacity influent pump station with a 60-foot diameter main shaft reaching approximately 150 feet below ground surface. This main shaft, located at the influent pump station, was complemented by a 20-foot diameter working shaft equipped with approach channels and vortex structures, as well as a 30-inch diameter drop pipe connected by an adit tunnel roughly 100 feet in length to the mainline tunnel. The project’s scope included building an IPS control building, odor control facilities with necessary ductwork, and installing electrical, monitoring, and control systems at both the working shaft and Porter Gaud drop pipe. Additionally, the existing near-surface collection system was modified to include gravity main and forcemain trenchless sliplining. Other critical upgrades included the construction of a new submersible grinder pump station, rehabilitation of an existing 100 GPM suction lift pump station, replacement of existing force and gravity mains, and building a 60-foot diameter dry pit housing five 15 MGD, 415-hp dry pit submersible pumps.