For the redevelopment of Williams Hill Business Center in downtown Saint Paul, Minnesota, the Saint Paul Port Authority hired Barr to install vapor mitigation measures in a building that houses multiple tenants, including a sign printer, bakery, parts supplier, and book warehouse. In addition, we coordinated and provided oversight and documentation to the Minnesota Pollution Control Agency and other stakeholders.
After selection of a mitigation contractor, Barr was hired to provide oversight, ongoing engineering support, and troubleshooting during installation of a sub-slab depressurization (SSD) system; perform ongoing monitoring and maintenance of the SSD system; and assist with achieving overall site closure. While SSD-system operation and maintenance is typically relatively straightforward, the fact that the port authority did not own the building presented some challenges. To address the owner's concerns about O&M, Barr installed a telemetry system that allowed the owner’s consultant to log in remotely, prepared an operations manual, and developed detailed O&M cost estimates.
Barr also evaluated and justified discontinuing and decommissioning a groundwater dual-phase extraction (DPE) system. With the resolution of the SSD and DPE systems, we assisted in obtaining site closure.