MAINSTREAM DEAMMONIFICATION WITH THE ANITA™MOX PROCESS

The originally developed ANITA™ Mox process was a single-stage deammonification process utilizing moving bed biofilm reactor (MBBR) technology. Previous studies demonstrated that the Integrated Fixed-Film Activated Sludge (IFAS) configuration was an effective approach to improve the ANITA™ Mox performance for sidestream treatment. The current ANITA™ Mox process includes both MBBR and IFAS configurations. In this study, IFAS ANITA™ Mox was successfully applied as a mainstream process to treat secondary effluent with low COD content at pilot-scale. The IFAS ANITA™ Mox’s unique feature of an easy and robust separation system (i.e. media sieves) to selectively retain the anammox biomass in the reactor is a clear advantage for mainstream application. Pilot trials on low COD effluent from C-stage MBBR achieved stable NH4-removal rates of 1.2 gN/m2.d at 23°C and 0.5 gN/m2.d at 15°C. With appropriate aeration and operation control, it was possible to achieve a good final effluent quality (TN<10-15 mg/L) without a further polishing step for N-removal and successfully repress NOB activity in the suspended sludge even at low temperatures. Additional studies are continuing to further show the advantage of the IFAS ANITA™ Mox process for mainstream deammonification application and demonstrate how this process can be integrated in a general WWTP scheme to deliver all the potential benefits on energy recovery and OPEX savings.