the investigation of viable treatment processes should be expanded to include an evaluation of the Integrated Fixed-Film Activated Sludge (IFAS) Process, including final filtration to produce a Class A-1 effluent. I believe that the IFAS process may result in less expensive initial construction costs and lower annual O&M costs, while also providing more flexible and simplified operations. The IFAS process utilizes a treatment train that is similar to the MBR including; screening, grit removal, anaerobic, anoxic and aerobic stages. Differences would include the need for a final clarifier, and a non-biological filter system. Many IFAS systems are currently producing high quality effluents in cold climates, and it should be a fairly simple process to evaluate initial construction and operating costs.
IFAS was not included in the original scope. AE2S did not encourage consideration of IFAS as our experience with IFAS, and knowing the site area constraints and treatment performance goals, IFAS would not be competitive.