“Second Generation” ATAD Success Stories – “Show Me the Data” - Several Years of Performance Data from Two Case Studies of Conversion from “First Generation” to “Second Generation” ATAD Systems

Autothermal Thermophilic Aerobic Digestion (ATAD) is becoming more prevalent due to its advantages over conventional aerobic digestion, including the generation of a Class “A” product, a relatively small footprint, and reduced biosolids volume for end use. Both the Grand Chute Menasha West Wastewater Treatment Facility (WWTF) in Neenah, Wisconsin and the Edwards WWTP operated by the Eagle River Water and Sanitation District located in Vail, Colorado originally installed “first generation” ATAD systems and have converted the systems to “second generation” ATAD systems.The “second generation” ATAD systems include process modifications over the “first generation” ATAD systems such as better mixing and process control that have resulted in higher volatile solids reduction, lower product volume, less odor generation and less sidestream impacts at several installations. This presentation will explore the advantages of the “second generation” ATAD systems over the original installations, the reasons why the two plants decided to convert their systems to the newer ATAD systems, and compare the actual performance of the Edwards, Neenah and other WWTPs with regard to total and volatile solids reduction, average reactor solids retention time (SRT) and temperature, centrate/filtrate ammonia concentration, dewatered cake solids concentration and fecal coliform concentration in dewatered cake.