ABL - Model FFR - Fixed Film Reactor
ABL has developed a Fixed Film Reactor (FFR) for applications which would be difficult with suspended-growth activated sludge processes. In the Fixed Film Reactor, plastic media is used in a series of tanks as a base on which to grow bacteria. The aeration system encourages the bed of media to gently roll in the tanks so that the wastewater and media are evenly distributed. The sequential tank arrangement prevents short circuiting of the wastewater and the loading gradient (high loading in the first stage and low loading in the last stage) promotes nitrification. The process can be compared to a Rotating Biological Contactor (RBC) without the shaft. This results in a reliable biological process without high mechanical requirements. The effluent from the Fixed Film Reactor contains sloughed biological growth which can be separated by gravity settling or Dissolved Air Flotation (DAF).
ABL's FFR was selected in an open competition for the UNESCO world heritage site in Lunenburg, Nova Scotia, Canada. The 'Lunenburg Process' uses the ABL-FFR in combination with DAF clarification and aerobic digestion of solids, and is designed to treat peak flows of 3 MGD. This process is equally applicable to small wastewater treatment systems as the control requirements are minimal. For small systems the solids removal can be accomplished in septic tanks and humus tanks. Further applications of the ABL-FFR are being investigated through pilot programs.