Lessons Learned from Startup and Commissioning of Three IFAS Facilities

The Integrated Fixed Film Activated Sludge (IFAS) process is a relatively new technology for controlling nitrogen and phosphorus discharges from wastewater treatment facilities in the US. There is widespread interest in this technology, especially for retrofitting existing facilities that face site constraints, expansion challenges, and/or the desire for a high quality effluent. Three facilities, Henry N. Wochholz Wastewater Treatment Plant (WWTP) in Yucaipa, California; Wildcat Hill WWTP in Flagstaff, Arizona; and a confidential facility in South Central US are covered in this paper. This paper discusses the startup challenges faced by these facilities, including IFAS basins loading, media containment, and aeration control. Challenges such as foaming during startup or stable operation have not been reported by most other IFAS facilities, which include Broomfield, Colorado; Cheyenne, Wyoming; and Flagstaff, Arizona. The exceptions have been Greensboro, North Carolina and the Region of Peel, Ontario, Canada. The Wochholz plant has experienced serious foaming problems during startup and some occasional foaming since the expansion has been completed. The confidential facility in South Central US has also reported some foaming issues. This paper discusses the causes, their investigation, and the measures taken to control foam. Recommendations for troubleshooting an IFAS plant during startup and operation are also discussed.