In-situ remediation of nitrate-contaminated ground water by electrokinetics/iron wall processes

Chin F. Chew, Tian C. Zhang

Research output: Contribution to journalConference article

50 Scopus citations

Abstract

The feasibility of using electrokinetics coupled with a zero valent iron (Fe0) treatment wall to abiotically remediate nitrate-contaminated soils was investigated. Upon completion of each test run, the contaminated soil specimen was sliced into five parts and analyzed for nitrate-nitrogen, ammonia-nitrogen and nitrite-nitrogen. Nitrogen mass balance was used to determine the major transformation products. In control experiments where only electrokinetics was used at various constant voltages, 25 to 37% of the nitrate-nitrogen was transformed. The amount of nitrate-nitrogen transformed improved when a Fe0 wall (20 g or about 8-10% by weight) was placed near the anode. For test runs at various constant voltages, the amount of nitrate-nitrogen transformed ranged from 54 to 87%. By switching to constant currents, the amount of nitrate-nitrogen - transformed was about 84 to 88%. The major transformation products were ammonia-nitrogen and nitrogen gases. Nitrite-nitrogen was less than 1% in all experimental runs. Two localized pH conditions exist in the system, a low pH region near the anode and a high pH region near the cathode. Placing of an iron wall near the anode increases the pH in that area as time increases. Movement of the acid front did not flush across the cathode. This research has demonstrated that the electrokinetics/iron wall process can be used to remediate nitrate-contaminated groundwater.

Original languageEnglish (US)
Pages (from-to)135-142
Number of pages8
JournalWater Science and Technology
Volume38
Issue number7 pt 6
DOIs
StatePublished - 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

  • Electrokinetics
  • Groundwater
  • In-situ remediation
  • Iron wall
  • Nitrates
  • Zero-valent iron

ASJC Scopus subject areas

  • Environmental Engineering
  • Water Science and Technology

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