HYPERION ADVANCED DIGESTION PILOT PROGRAM

The City of Los Angeles is preparing for the future by pilot testing advanced biosolids processing scenarios. This long range planning effort examines the current operational mode of the digesters at the City of Los Angeles' Hyperion Treatment Plant, to determine which digestion scenario will best produce Class A Biosolids as specified by the 503 regulations. The digestion options selected for investigation included a Two-Phase Acid (Thermo)/Methane (Meso) system, a Temperature Phased Thermo/Meso system and a Food Waste Single Stage Thermophilic scenario. Pilot testing of the selected digestion options required the construction of a pilot facility. Based on results from the pilot program, this paper discuss the die-off rates for both fecal coliform and Salmonella, possible sources of sample contamination, comparable gas production rates between the pilot facility and the plant, and VSD performance between the Two-Phase Acid/Methane digestion and Temperature Phased Thermo/Meso digestion. The digestion future of Hyperion has prompted design questions, which will be discussed from the Temperature Stress Test and a specialty test of Food Waste digestion.