Why Use Submersbles In A Dry-Pit Pump Station Application?

Spurred by concerns over the potential of pump station flooding—whether a dry-pit resides in a flood plain or experiences the ill-effects of failed mechanical seals and valves—many cities, engineers and developers often specify submersible pumps for dry-pit environments. At first glance, the logic seems reasonable: a “submersible” should theoretically run in the rare event of a dry-pit flooding. Yet, submersible pumps are specifically designed for wet pits, hence their name. More than that, the surrounding wastewater keeps the submerged pump motor properly cooled in order to maintain reasonable performance. When submersibles operate in a dry-pit application, they require extra fixtures and retooling in order to compensate for the lack of cooling when not submerged—in this case nearly 99.9 percent of the time. This begs the question, “Why use a ‘submersible’ in a ‘dry’ application?”