Abstract
Whereas ion exchange is an attractive technology for treating perchlorate and nitrate in drinking water, a major disadvantage is that the resin must be regenerated using a brine, producing wastes with high concentrations of nitrate, perchlorate, and salt. This study investigates the potential for simultaneous nitrate and perchlorate reductions in high-salt conditions using the H2-based membrane biofilm reactor (MBfR). The autotrophic biological reductions produce harmless N2 and Cl-, making the brine safe for reuse or disposal. A very high-strength brine (∼15% salt) from a commercial ion-exchange membrane, Purolite, supported biofilm accumulation and allowed slow reduction rates for nitrate and perchlorate. Reduction rates increased significantly when the Purolite brine was diluted by 50% or more. A synthetic high-strength salt medium containing nitrate, perchlorate, or both supported more rapid reduction rates for as high as 20g/L (∼2%) NaCl, while 40g/L NaCl slowed reduction by 40% or more, confirming that the microorganisms in the MBfR were inhibited by high salt content. An increase of H2 pressure gave higher fluxes for 20g/L NaCl, demonstrating that H2 availability controlled the reduction kinetics when the system was not salt-inhibited.
Original language | English (US) |
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Pages (from-to) | 157-164 |
Number of pages | 8 |
Journal | Journal of Environmental Engineering |
Volume | 133 |
Issue number | 2 |
DOIs | |
State | Published - Feb 2007 |
Keywords
- Biofilm
- Biological treatment
- Brines
- Nitrates
- Reactors
- Water treatment
ASJC Scopus subject areas
- General Environmental Science
- Environmental Engineering
- Environmental Chemistry
- Civil and Structural Engineering