Effects of hydraulic retention time and S2O2−3 /NO3 3ratio on thiosulfate-driven autotrophic denitrification for nitrate removal from micro-polluted surface water

Zheng Wang, Xiang Fei, Sheng bing He, Jung chen Huang, Wei li Zhou

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5 Citations (Scopus)

Abstract

This study was carried out to investigate the possibility of a thiosulfate-driven autotrophic denitrification for nitrate-N removal from micro-polluted surface water. The aim was to study the effects of S2O2−3 /NO3 ratio (S/N molar ratio) and hydraulic retention time (HRT) on the autotrophic denitrification performance. Besides, utilization efficiencies of S2O2−3 −S along the biofilter and the restart-up of the bioreactor were also investigated. Autotrophic denitrification using thiosulfate as an electron donor for treating micro-polluted surface water without the addition of external alkalinity proved to be feasible and the biofilter could be readied in two weeks. Average nitrate-N removal efficiencies at HRTs of 0.5, 1 and 2 h were 78.7%, 87.8% and 97.4%, respectively, and corresponding removal rates were 186.24, 103.92 and 58.56 g NO3 −N/(m3 · d), respectively. When water temperature was in the range of 8–12°C and HRT was 1 h, average nitrate-N removal efficiencies of 41.9%, 97.1% and 97.0%, nitrite accumulation concentrations of 1.45, 0.46 and 0.22 mg/L and thiosulfate utilization efficiencies of 100%, 98.8% and 92.1% were obtained at S/N ratios of 1.0, 1.2 and 1.5, respectively. Besides, the autotrophic denitrification rate in the filtration media layer was the highest along the biofilter at an S/N ratio of 1.5. Finally, after a one-month period of starvation, the biofilter could be restarted successfully in three weeks without inoculation of seed sludge.

Original languageEnglish
Pages (from-to)2835-2843
Number of pages9
JournalEnvironmental Technology (United Kingdom)
Volume38
Issue number22
DOIs
Publication statusPublished - 2017 Nov 17

All Science Journal Classification (ASJC) codes

  • Environmental Chemistry
  • Water Science and Technology
  • Waste Management and Disposal

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