One-Stage Deammonification Process - MBBR Versus IFAS Configurations - Development Updates and Application Considerations

The ANITA™ Mox Process is a single-stage deammonification process utilizing moving bed biofilm reactor (MBBR) technology. Early studies indicated that the Integrated Fixed-Film Activated Sludge (IFAS) configuration was an effective approach to improve ANITA™ Mox performance. Two studies on ANITA™ Mox IFAS were conducted at full-scale and pilot-scale levels. The full-scale study compared the IFAS and MBBR configurations side-by-side in 50-m3 reactors. The second study was a pilot study on the IFAS configuration conducted in the U.S.A. Both studies investigated the nitrogen removal performance and sludge settleability under optimized operating conditions.The two studies confirmed that the nitrogen removal rate in the IFAS configuration was 2 to 2.5 times higher than that in the MBBR configuration with similar or better ammonia and total inorganic nitrogen (TIN) removal efficiencies. The operating conditions for the IFAS are typically 2.5-5.0 g/L of MLSS and 0.3-0.8 mg/L of DO. The sludge settleabilty from both IFAS studies was good, as indicated by SVIs between 70 to 100 mL/g. The clarifier was able to retain the suspended biomass required for the better performance, even though the effluent TSS was relatively high (100 to 500 mg/L) and mostly dependent on the incoming reject water TSS spikes. Based on the experimental results, the suitability of MBBR and IFAS configurations for full-scale applications was discussed.