When Nashville (Tennessee) Central Wastewater Treatment Plant personnel were tasked to find a screening solution to remove the high-debris content in their biosludge, the first action they took was to pilot the SAVECO/Enviro-Care BEAST. Originally designed as a septage screening system, the BEAST has shown its ability to handle a wide variety of pretreatment screening applications such as fats, oils and grease; vac truck waste; dissolved air flotation sludge; and biological sludge.
Easy screening
Nashville Central’s biosludge is composed of primary sludge, scum and secondary waste-activated sludge. The BEAST had no difficulty screening this mixture. While awaiting the completion of its screening building, Nashville ordered three Sludge BEASTS mounted on metal skids along with a washer/compactor for each BEAST. This enabled Nashville to easily move and position the BEAST at various places in the plant until the sludge screening facility was completed.
After screening by the BEAST, the biological feed continues to a DAF thickening system where the biomass is brought to a 5% solids content and eventually makes it way to one of the 2.5 million-gallon digesters where the feed is retained for 17 days and undergoes a 40% volume reduction. This generates enough gas (energy) to both heat the digesters and dry the biosludge. The dried biosludge is then pelletized and classified as a Grade A EQ (exceptional quality) biosolid product to be used as fertilizer. This classification exceeds U.S. Environmental Protection Agency guidelines.
As the city of Nashville continues to grow, the SAVECO/Enviro-Care BEAST screening systems will provide Nashville Central Wastewater Treatment Plant with exactly what it needs to achieve a significant reduction in maintenance and wear on its sludge process equipment, a clean Grade A EQ biosolid, and an overall more efficient energy production process.
SAVECO North America of Gurnee, Illinois, supplies pretreatment screens and solids/grit management equipment for water and wastewater applications. The company was founded in 1972.
815-636-8306 | ecsales@savecowaterna.com | www.savecowaterna.com