Sulfur-based autotrophic denitrification pond systems for in-situ remediation of nitrate-contaminated surface water

Joel M. Flere, Tian C. Zhang

Research output: Contribution to journalConference article

26 Scopus citations

Abstract

The feasibility of using the sulfur/limestone autotrophic denitrification (SLAD) process as an in-situ method for remediation of nitrate-contaminated surface water was investigated. Four bench-scale pond systems with working volumes of 21.4 litres each and hydraulic retention time (HRT) of 30 days were operated under either mixed conditions or unmixed conditions. Under mixed (aerobic) conditions, with the addition of alkalinity to raise pH, NO3 --N removal in the SLAD ponds were 85-100%, while the control reactor showed negative removal. Sulfate production under mixed conditions, due to the activities of non-denitrifying bacteria such as Thiobacillus thiooxidans, was between 1000-2500 mg/l SO4 2-, which makes the application of the SLAD ponds under aerobic conditions questionable. Under unmixed (anoxic) conditions, NO3 --N removal in the SLAD ponds decreased to 75-88%; sulfate production, however, also decreased by more than 50% due to the inhibition of the activity of non-denitrifying bacteria. Additional batch experiments indicated that sulfate production in the SLAD systems was acceptable under anoxic conditions. Therefore, the application of the SLAD ponds under unmixed (anoxic) conditions is feasible for in-situ remediation of nitrate-contaminated surface water.

Original languageEnglish (US)
Pages (from-to)15-22
Number of pages8
JournalWater Science and Technology
Volume38
Issue number1 pt 1
DOIs
Publication statusPublished - Jan 1 1998
EventProceedings of the 1998 19th Biennial Conference of the International Association on Water Quality. Part 1 (of 9) - Vancouver, Can
Duration: Jun 21 1998Jun 26 1998

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Keywords

  • Autotrophic denitrification
  • In-situ remediation
  • Nitrates
  • Sulfur
  • Thiobacillus denitrificans
  • Thiobacillus thiooxidans

ASJC Scopus subject areas

  • Environmental Engineering
  • Water Science and Technology

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