CHANGGuo-song,YUJing-jie,WANGShao-po,et al.Effect of Internal Recirculation Frequency on Denitrifying Phosphorus Removal in Oxidation Ditch[J].China Water & Wastewater,2022,38(21):12-19.
Effect of Internal Recirculation Frequency on Denitrifying Phosphorus Removal in Oxidation Ditch
China Water & Wastewater[ISSN:1000-4062/CN:12-1073/TU]
volume:
第38卷
Number:
第21期
Page:
12-19
Column:
Date of publication:
2022-11-01
- Keywords:
- oxidation ditch; internal recirculation frequency; aerobic phosphorus removal; denitrifying phosphorus removal; extracellular polymers
- Abstract:
- The phosphorus mass balance in a modified oxidation ditch (OD) with anaerobic zone in front of the circular corridor and anoxic and aerobic zones in the circular corridor was analyzed by determining the proportion of denitrifying phosphorus accumulating bacteria in the total phosphorus accumulating bacteria (DPAOs/PAOs) and the phosphorus concentration in wastewater and sludge. The effects of the internal recirculation frequency (cycles number of mixed liquor circulating in circular corridor per unit time, IRF) of the mixed liquor in the circular corridor on pollutants removal and phosphorus conversion pathways were investigated when the IRF varied from 0.52 circles/h to 18.74 circles/h. When IRF was not more than 1.62 circles/h, it was beneficial to store more phosphorus in cells to form intracellular polyphosphates. When IRF was between 3.36 circles/h and 7.53 circles/h, it was conducive to denitrifying phosphorus removal, and the system achieved better simultaneous nitrogen and phosphorus removal performance. In addition, the ratio of DPAOs to PAOs was approximately 50%, and the average removal rates of COD, TN and TP reached above 92%, 80% and 93%, respectively. When IRF was not less than 11.35 circles/h, the TN removal performance was not good, and it was not conducive to efficient simultaneous nitrogen and phosphorus removal.
Last Update:
2022-11-01