Challenge: The WWTP was originally constructed with three 36” diameter Archimedes’ Screw Pumps, which lifted influent wastewater from an influent basin to a trough at the top of a concrete oxidation ditch.
On occasion, influent wastewater would leak and spray from the top of the screw pumps onto a concrete pad at the base of the concrete oxidation ditch, just outside of the oxidation ditch. When this happened, a screw pump would need to be serviced, which typically required the rental of a crane to remove the screw pump. The screw pump would then need to be transported off-site for service. Each screw pump maintenance event was inconvenient and expensive.
Solution: The Authority directed us to design influent pumping modifications with the objective of replacing the screw pumps with submersible pumps, obtaining the WQM Permit Amendment for the influent pumping modifications, and assisting the Authority with retaining the contractors to construct the modifications.
Outcome: From receiving direction to beginning the assignment in the spring of 2013, all work on construction of the pumping modifications was completed by September 2013.