Perchlorate removal in sand and plastic media bioreactors

Booki Min, Patrick J. Evans, Allyson K. Chu, Bruce Ernest Logan

Research output: Contribution to journalArticle

73 Citations (Scopus)

Abstract

The treatment of perchlorate-contaminated groundwater was examined using two side-by-side pilot-scale fixed-bed bioreactors packed with sand or plastic media, and bioaugmented with the perchlorate-degrading bacterium Dechlorosoma sp. KJ. Groundwater containing perchlorate (77μg/L), nitrate (4mg-NO 3/L), and dissolved oxygen (7.5mg/L) was amended with a carbon source (acetic acid) and nutrients (ammonium phosphate). Perchlorate was completely removed (<4μg/L) in the sand medium bioreactor at flow rates of 0.063-0.126L/s (1-2gpm or hydraulic loading rate of 0.34-0.68L/m 2s) and in the plastic medium reactor at flow rates of <0.063L/s. Acetate in the sand reactor was removed from 43±8 to 13±8mg/L (after day 100), and nitrate was completely removed in the reactor (except day 159). A regular (weekly) backwashing cycle was necessary to achieve consistent reactor performance and avoid short-circuiting in the reactors. For example, the sand reactor detention time was 18min (hydraulic loading rate of 0.68L/m2s) immediately after backwashing, but it decreased to only 10min 1 week later. In the plastic medium bioreactor, the relative changes in detention time due to backwashing were smaller, typically changing from 60min before backwashing to 70min after backwashing. We found that detention times necessary for complete perchlorate removal were more typical of those expected for mixed cultures (10-18min) than those for the pure culture (<1min) reported in our previous laboratory studies. Analysis of intra-column perchlorate profiles revealed that there was simultaneous removal of dissolved oxygen, nitrate, and perchlorate, and that oxygen and nitrate removal was always complete prior to complete perchlorate removal. This study demonstrated for the first time in a pilot-scale system, that with regular backwashing cycles, fixed-bed bioreactors could be used to remove perchlorate in groundwater to a suitable level for drinking water.

Original languageEnglish (US)
Pages (from-to)47-60
Number of pages14
JournalWater Research
Volume38
Issue number1
DOIs
StatePublished - Jan 1 2004

Fingerprint

perchlorate
Bioreactors
bioreactor
Nitrates
Sand
plastic
Plastics
Groundwater
sand
Dissolved oxygen
Flow rate
Hydraulics
nitrate
Acetic acid
Potable water
Nutrients
Bacteria
Phosphates
groundwater
dissolved oxygen

All Science Journal Classification (ASJC) codes

  • Ecological Modeling
  • Water Science and Technology
  • Waste Management and Disposal
  • Pollution

Cite this

Min, Booki ; Evans, Patrick J. ; Chu, Allyson K. ; Logan, Bruce Ernest. / Perchlorate removal in sand and plastic media bioreactors. In: Water Research. 2004 ; Vol. 38, No. 1. pp. 47-60.
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Perchlorate removal in sand and plastic media bioreactors. / Min, Booki; Evans, Patrick J.; Chu, Allyson K.; Logan, Bruce Ernest.

In: Water Research, Vol. 38, No. 1, 01.01.2004, p. 47-60.

Research output: Contribution to journalArticle

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