Removal and Transformation of Pollutants in a Two-Line Denitrifying Phosphorus Removal Process Treating Low C/N Municipal Wastewater: Influence of Hydraulic Retention Time

  • Hongbo Liu
  • Yangyang Yao
  • Suyun Xu


A two-line denitrifying phosphorus removal process (2L-DPR) was established treating low C/N municipal wastewater efficiently in our previous studies, while hydraulic retention time (HRT) is one of the most important factors determining the substrate loading, contact time for biomass, and pollutants and further affect performance of the whole system. Removal and transformation mechanism of organic carbon (C), nitrogen (N), and phosphorus (P) were investigated together with mass balance under various HRTs (6, 9, and 18 h) in the established 2L-DPR process. The results showed that in anaerobic units, the concentration of the main storage products in activated sludge such as poly-hydroxyvalerate (PHV) and poly-hydroxybutyrate (PHB) at HRT of 9 h was higher than that under other HRTs. The highest TN and TP removal efficiency was also achieved under the HRT of 9 h with removal rates of 55.9% and 84.6% respectively. Increasing HRT from 6 to 9 h greatly enhanced TN removal in anoxic and aerobic units; however, HRTs had little influence on COD removal with effluent concentration of 48.6, 49.1, and 48.9 mg/L, respectively. HRT affected phosphorus up-taken in anoxic and aerobic units rather than on the release of phosphorus processes in anaerobic units.


Municipal wastewater Biological nutrient removal (BNR) Denitrifying phosphorus removal Hydraulic retention time (HRT) Low C/N ratio 


Funding information

This study was financially supported by the Natural Science Foundation of China (NSFC No. 21206092) and the RTTC-China 2014 project.

Compliance with Ethical Standards

Conflict of Interest

The authors declare that they have no conflict of interest.

Supplementary material

11270_2018_3746_MOESM1_ESM.jpg (268 kb)
ESM 1 Fig. 1 Configuration of the 2L-DPR reactor. (JPEG 268 kb)


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© Springer International Publishing AG, part of Springer Nature 2018

Authors and Affiliations

  1. 1.School of Environment and ArchitectureUniversity of Shanghai for Science and TechnologyShanghaiChina

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