A new biological nutrient removal process, anaerobic–oxic–anoxic (A/O/A) system using denitrifying polyphosphate-accumulating organisms (DNPAOs), was proposed. To attain excess sludge reduction and phosphorus recovery, the A/O/A system equipped with ozonation tank and phosphorus adsorption column was operated for 92 days, and water quality of the effluent, sludge reduction efficiency, and phosphorus recovery efficiency were evaluated. As a result, TOC, T-N and T-P removal efficiency were 85%, 70% and 85%, respectively, throughout the operating period. These slightly lower removal efficiencies than conventional anaerobic–anoxic–oxic (A/A/O) processes were due to the unexpected microbial population in this system where DNPAOs were not the dominant group but normal polyphosphate-accumulating organisms (PAOs) that could not utilize nitrate and nitrite as electron acceptor became dominant. However, it was successfully demonstrated that 34–127% of sludge reduction and around 80% of phosphorus recovery were attained. In conclusion, the A/O/A system equipped with ozonation and phosphorus adsorption systems is useful as a new advanced wastewater treatment plant (WWTP) to resolve the problems of increasing excess sludge and depleted phosphorus.
Evaluation of sludge reduction and phosphorus recovery efficiencies in a new advanced wastewater treatment system using denitrifying polyphosphate accumulating organisms
Y. Suzuki, T. Kondo, K. Nakagawa, S. Tsuneda, A. Hirata, Y. Shimizu, Y. Inamori; Evaluation of sludge reduction and phosphorus recovery efficiencies in a new advanced wastewater treatment system using denitrifying polyphosphate accumulating organisms. Water Sci Technol 1 March 2006; 53 (6): 107–113. doi: https://doi.org/10.2166/wst.2006.179
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