Abstract
In recent years, several oxyanions have emerged as drinking water micropollutants, including arsenate, selenate, bromate, and, most recently, perchlorate (ClO4-). Conventional water treatment processes typically are ineffective in removing these compounds, and advanced treatment processes are expensive. Biological reduction may provide a suitable treatment alternative, since these compounds can serve as electron acceptors. Other acceptors, such as nitrate (NO3-), must act as a primary electron acceptor. We tested our denitrifying, autotrophic, hydrogen-oxidizing hollow-fiber membrane for ClO4- reduction. The reactor is highly suited to drinking water treatment, as hydrogen (H2) is inexpensive, nontoxic, and does not leave residuals that can cause regrowth. When 1 to 2 mg/L ClO4- was supplied to reactor, which was at steady-state with 5 mgN/L NO3- but unacclimated to ClO4-, ClO4- removals increased from 40 to 99% over three weeks. Removals to 4 μg/L were also achieved in a natural groundwater having 6 to 100 μg/L ClO4-. Tests with variable NO3- and H2 showed that ClO4- reduction requires less than 30 μgN/L NO3- and at least 300-μg/L effluent H2. Therefore, partial denitrification is probably not consistent with excellent ClO4- removal. Mineral medium produced a gradual loss of ClO4- reducing bacteria, but they were re-enriched when tap water replaced minimal medium.
Original language | English (US) |
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Pages (from-to) | 259-265 |
Number of pages | 7 |
Journal | Water Science and Technology: Water Supply |
Volume | 2 |
Issue number | 2 |
DOIs | |
State | Published - 2002 |
Externally published | Yes |
Keywords
- Biofilm reactor
- Denitrification
- Hollow-fiber membrane
- Perchlorate reduction
- Secondary substrate
ASJC Scopus subject areas
- Water Science and Technology