A modeling understanding on the phosphorous removal performances of A2O and reversed A2O processes in a full-scale wastewater treatment plant
Reversed A2O process (anoxic-anaerobic-aerobic) and conventional A2O process (anaerobic-anoxic-aerobic) are widely used in many wastewater treatment plants (WWTPs) in Asia. However, at present, there are still no consistent results to figure out which process has better total phosphorous (TP) removal performance and the mechanism for this difference was not clear yet. In this study, the treatment performances of both processes were compared in the same full-scale WWTP and the TP removal dynamics was analyzed by a modeling method. The treatment performance of full-scale WWTP showed the TP removal efficiency of the reversed A2O process was more efficient than in the conventional A2O process. The modeling results further reveal that the TP removal depends highly on the concentration and composition of influent COD. It had more efficient TP removal than the conventional A2O process only under conditions of sufficient influent COD and high fermentation products content. This study may lay a foundation for appropriate selection and optimization of treatment processes to suit practical wastewater properties.
KeywordsReversed A2O Total phosphorous (TP) Modeling Wastewater Phosphorus accumulating organisms
This study was funded by the National Natural Science Foundation of China (51408587; 51522812; 51778301).
- APHA (1998) Standard methods for the examination of water and wastewater. American Public Health Association, Washington DCGoogle Scholar
- Bi XJ, Zhang B (2006) The principle and full-scale application of reversed A2O process for removing nitrogen and phosphorus. Environ Eng (in Chinese) 24:29–31Google Scholar
- Grady Jr CPL, Daigger GT, Lim H (1999) Biological wastewater treatment. Revised and Expanded, 2nd edn. Marcel Dekker, New YorkGoogle Scholar
- Hu X, Wisniewski K, Czerwionka K, Zhou Q, Xie L (2016) Modeling the effect of external carbon source addition under different electron acceptor conditions in biological nutrient removal activated sludge systems. Environ Sci Technol 50:1887–1896Google Scholar
- Lahav O, Loewenthal RE (2000) Measurement of VFA in anaerobic digestion: the five-point titration method revised. Water SA 26:389–392Google Scholar
- Li P, Bi XJ, Wang J, Ru SG (2017) Microbial diversity in activated sludges of conventional and reversed A2/O processes. China Environ Sci (in Chinese) 37:1137–1145Google Scholar
- Liu CQ, Zhang F, Bi XJ, Zhang B (2008) Contrast between reversed A2O process and improved A2O process in full-scale test. Technol Wat Treat 34:53–56Google Scholar
- Reichert P (1998) Aquasim 2.0-User Manual, Computer Program for the Identification and Simulation of Aquatic Systems. EAWAG, Dübendorf, SwitzerlandGoogle Scholar