Wharton Treatment Plant No. 2 - Wharton, Texas

Persistent permit violations brought about this project, which started with an in-depth investigation of system customers to determine the source of the permit excursions. Severe influent concentration spikes were sampled and traced back to dischargers who were non-compliant with the City's pretreatment program. The design of the treatment plant improvements was centered on a new basis for influent characteristics that were developed to more accurately reflect the City's true influent wastewater. A new elevated headworks was constructed which included a mechanical bar screen and screenings compactor. The existing 0.5 MGD RBC system was taken off-line and a new extended aeration Carrousel was built to replace it. The added volume and extended detention time provided dilution for spikes and increased treatment for the high CODs the plant was experiencing. To save on electrical costs the City opted for the installation of an automatic aerator control system, which uses dissolved oxygen meters and Variable Frequency Drives to control the amount of oxygen transferred into the system. By maintaining a lower dissolved oxygen concentration during low flows, the City reduced the overall power requirements by 50%.