The CFIC® (Continuous Flow Intermittent Cleaning) biofilm reactor has been developed. It contains highly packed biofilm carriers to a degree that little movement of the carriers occurs in the reactor during normal operation.
The process has continuous inflow to the bioreactor and intermittent forward flow cleaning, which removes excess biomass from the biofilm carriers. During the forward-wash cycle (FWC) the water level in the reactor is elevated just enough to provide free movement of the carriers.
This new process has been tested for municipal wastewater at specific organic loads up to 60 g COD/m2-d, and for industrial wastewater at specific organic loads up to 110 g COD/m²-d.
The forward-wash water contains very high SS concentrations, but has a very low SVI and a low soluble COD concentration. The high biofilm carrier packing density during normal operation enhances the specific oxygen transfer rate (OTR).
Off-gas measurements showed the OTR in CFIC® mode to be about twice the OTR in MBBR mode. A full-scale design of a MBBR and a CFIC® process for secondary treatment of municipal wastewater, showed the aeration energy requirement for the CFIC® process to be about 60 % of the requirement for the MBBR process.
Contact author for copy:
Siljudalen, Jon G.; Marcolini, Laura; Xin, Gang; Stang, Pascale and Rusten, Bjorn: Sustainable wastewater treatment with the innovative CFIC® biofilm reactor process. Paper presented at Singapore International Water Week (SIWW), 2014.