INTEGRATED FIXED-FILM ACTIVATED SLUDGE (IFAS) TECHNOLOGY FOR WWTP UPGRADES

Economically upgrading existing facilities can be one of the most challenging tasks of owners, operators, and engineers. Extensive communication, exchange of ideas, sharing of talents, concerns, needs, and performance objectives is crucial. The group must work as a team to push the technology envelope. Application of Integrated Fixed-film Activated Sludge (IFAS) Technology provides a new approach to expanding the capacity of Activated Sludge Systems without capital spending on new tanks and or clarifiers.When upgrading Activated Sludge Systems, whether for enhanced BOD removal capacity or for enhanced nitrogen removal, the most common problem encountered is the inability to develop sufficient biomass and contact time to process additional BOD or ammonia nitrogen. Overcoming the process limitations usually requires, at a minimum, increasing clarifier solids load capacity to maintain a reasonable solids loading and/or increasing aeration tank volume to increase active biomass. IFAS Technology addresses the needed increase in biomass without the direct need for increased clarifier capacity and/or additional tankage.This paper will provide a brief IFAS technology overview, a design example, and a case study for meeting nitrification requirements for Greensboro, North Carolina.