Self-Sustained Nitrite Accumulation at Low pH Greatly Enhances Volatile Solids Destruction and Nitrogen Removal in Aerobic Sludge Digestion

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

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Author(s)

  • Haoran Duan
  • Liu Ye
  • Xuanyu Lu
  • Damien J. Batstone
  • Zhiguo Yuan

Detail(s)

Original languageEnglish
Pages (from-to)1225-1234
Journal / PublicationEnvironmental Science and Technology
Volume53
Issue number3
Publication statusPublished - 5 Feb 2019
Externally publishedYes

Abstract

Aerobic sludge digestion of waste activated sludge (WAS) is widely used as a stabilization option in small-and midsized wastewater treatment plants. However, the digestion process is often limited by low volatile solids (VS) destruction and poor pathogen removal efficiency. This study presents a novel operational strategy that achieves enhanced VS destruction and nitrogen removal by inducing sustained nitrite accumulation via a single spike of nitrite to aerobic digester operated at a natively low pH (<5.5). The strategy was demonstrated through the use of three laboratory aerobic sludge digesters, each continuously operated for over 300 days. Compared to control reactors, the strategy enhanced volatile solids destruction by 35.0-38.4%, nitrogen removal by 58.5-70.8%, and pathogen reduction by approximately 1 log. The standard oxygen uptake rate (SOUR) was reduced to 0.49 ± 0.03 mgO 2 /gVS/h, compared to 0.85 ± 0.01-1.68 ± 0.02 mgO 2 /gVS/h in the control, indicating enhanced stabilization. Free nitrous acid formed from nitrite at low pH, rather than nitrite itself, was identified to be the cause of improved digestion performance. Since the nitrite production is self-supporting, no additional ongoing costs are incurred. Copyright © 2018 American Chemical Society.

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Citation Format(s)

Self-Sustained Nitrite Accumulation at Low pH Greatly Enhances Volatile Solids Destruction and Nitrogen Removal in Aerobic Sludge Digestion. / Duan, Haoran; Ye, Liu; Lu, Xuanyu et al.
In: Environmental Science and Technology, Vol. 53, No. 3, 05.02.2019, p. 1225-1234.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review