by Leslie Lytle, Messenger Staff Writer

At the May 17 meeting, the Sewanee Utility District Board of Commissioners approved purchasing two variable speed drives (VFD’s) for the water treatment plant pumps which will enable regulating the speed of the motors, saving energy. The board also reviewed cost estimates for a bar screen for the wastewater pumping station to filter out disposable wipes and face masks which damage the pumps.

SUD manager Ben Beavers said the two VFDs, cost $22,500, would cut power consumption in half. Currently there is no way to regulate pump speed and the water plant regulates the flow by partially closing the discharge. The price from the vendor selected is slightly higher than another vendor, but the vendor could provide delivery in two weeks instead of five months. The vendor will install the VFDs and integrate them with SUD’s system. The VFDs will lower the power consumption at the water treatment plant, decrease the wear and tear of the main discharge valve, and decrease the overall system pressure. Beavers projected the units would pay for themselves in less than three years.

SUD intends to replace the bar screen at the main sewer pumping station to prevent disposable wipes and face masks from clogging and damaging pumps and creating a health hazard for employees tasked with repair. Beavers said the three options available differed in cost, method of operation, and the amount of debris removed. In the $125,000 unit, a rake scraped the screen. In the $180,000 unit, the screen moved across the rake. In the $225,000 unit, the water flowed through plates with holes which rotated to dump the debris. The most expensive unit removed far smaller debris and grit, according to Beavers. Tullahoma used that unit and was very satisfied. Beavers will visit a wastewater treatment plan in Georgia which uses the least expensive unit to investigate the system’s effectiveness. He suggested it might be wise to purchase two of the less expensive units and install a screen both at the main pumping station and before the pumps which draw water from the lagoon. “It would be worth a $100 if it saves a couple pumps,” Beavers said. Board President Charlie Smith asked which system best protected SUD employees from dealing with waste. “If they [bar screens] work like they should, they all would,” Beavers said.