Development of a Biological Nutrient Removal Model with the Shortened Operating Cycle Time for AnA2/O2 SBR2

Assoc. Prof.Dr. Prayoon Fongsatitkul
Faculty of Public Health, Mahidol University

This research aimed to investigate the role of the long sludge age and short cycle time of AnA2/O2, in an 8-hr operation cycle, to enhance organics and nutrient (N and P) removal efficiency from slaughterhouse wastewater. Effects of the first anoxic time/second anoxic time ratios and SRT were investigated, varying 3 different proportions of the first anoxic time to second anoxic time ratios of 1:8, 1:6 and 1:4, with SRT of 60, 70, and 80 days. Additionally, mechanistic model based on analysis and simulation of the biological nutrient removal processes was developed.
The results showed that the COD, TKN, and TP removal efficiencies were in the range of 94.35%-99.59%, 63.20%-99.63%, and 74.72%-99.45%, respectively. The average COD, TKN, and TP removal efficiencies were affected by SRT. The average TKN, and TP removal efficiency at SRT of 70 days was significantly higher than that of SRT of 60 days (p<0.05). In addition, the average COD removal efficiency at SRT of 60 days was significantly higher than that of SRT of 80 days (p<0.05). Whereas, the average COD, TKN, and TP removal efficiency showed no significant difference at the first anoxic time/ second anoxic time ratios of 1:8, 1:6, and 1:4.
The model development for describing the biological behaviors of nitrogen and phosphorus removal was developed based on activated sludge model. Model calibration was carried out on the separate batch experiments for denitrification, nitrification, phosphorus release, and phosphorus uptake batch. Based on the sensitivity analysis results, the µH,S, ηNO2, ηNO3, kSTO, YH,S, and YH,STO had an influence on the denitrification process. The µAOB, µNOB, YAOB and YNOB had an influence on the nitrification process. The qPO4, qPP, YPHA, Kmax,PAO had an influence on the biological phosphorus removal. The presented model was verified by the experiment of AnA2/O2 SBR treating slaughterhouse wastewater. A high correlation between the measured and simulated results was obtained, suggesting the validity of the model. A Model was used to simulate the biological nutrient removal in AnA2/O2 SBR, it found that the main processes for COD, nitrogen, and phosphorus removal were occurring at Anoxic I and Oxic I periods. While, Anoxic II, and Oxic II were performed on the sludge stabilization.
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แหล่งข้อมูล:

  • โครงการวิจัยชื่อ “Development of a Biological Nutrient Removal Model with the Shortened Operating Cycle Time for AnA2/O2 SBR2″ – ระยะเวลาโครงการ: August 2013 – July 2015