NC0025321_SOC - September 2021 Quarterly Report_20220414

September 2021
Quarterly report as required by SOC section 2 (b) 8. The most southern Primary clarifier gear box failed
causing the clarifier to be offline for 2 months. We had the existing electric motor rebuilt. This took 3
weeks for the rebuild and replacement. Once it was put back into operation the motor failed again the
next day. Brigman electric determined the motor was just unable to be rewired anymore. This motor
had been rewired multiple times over the years. A modern electric motor could not be placed on the
gear due to the shape configuration of the motor housing. We had to have an adapter piece fabricated
by Custom CNC in Clyde NC. It was determined that the motor was a 1965 electric motor. This process
took several weeks with several trips by Custom CNC to the plant to pull measurements. Once we got
the motor and adaptor plate on, we were able to successfully restart the clarifier.
Once the southern clarifier was restarted, we had a few weeks of normal operation. The most northern
primary clarifier started tripping out and having to be reset multiple times per day. The tension trip
mechanism showed that the clarifier was being overloaded. We conducted several sludge depth tests
throughout the clarifier and the sludge depth was not excessive. We drained the clarifier, and nothing
was found to be causing a bind in the scrapers. After much trouble shooting and inspecting various
parts. We determined that there was a bad set of electrical contacts in the old electrical panel. This
system worked off mercury limit switches. We replaced all the electrical fee service for this clarifier.
Plant upgrade plans is being finalized. This project will go out to bid soon.