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Published on: October 15, 2015
Biological perchlorate reduction in packed bed reactors using elemental sulfur.
Ashish K Sahu1, Teresa Conneely, Klaus R Nüsslein
1Aquateam-Norwegian Water Technology Centre A/S, Oslo, Norway.
Environmental Science & Technology
|July 17, 2009
Summary
Sulfur-reducing bacteria effectively removed perchlorate (ClO4-) in packed bed reactors. Biofilm acclimation and growth, not mass transfer, were key to perchlorate reduction, with nitrate inhibiting the process.
Area of Science:
- Environmental microbiology
- Bioremediation technologies
- Water quality management
Background:
- Perchlorate (ClO4-) contamination poses environmental and health risks.
- Biological treatment using sulfur-reducing bacteria is a promising remediation strategy.
- Understanding microbial community dynamics is crucial for optimizing bioreactors.
Purpose of the Study:
- To enrich and characterize sulfur-utilizing perchlorate-reducing bacteria.
- To evaluate the performance of packed bed reactors (PBRs) for perchlorate removal.
- To investigate factors affecting bioreactor efficiency, including substrate particle size, recirculation, and nitrate presence.
Main Methods:
- Enrichment of perchlorate-reducing bacteria from a denitrifying wastewater source using elemental sulfur (S0).
- Operation of bench-scale packed bed reactors (PBRs) with S0 and oyster shell media.
- Analysis of perchlorate concentrations, microbial community composition, and operational parameters.
Main Results:
- Efficient perchlorate reduction achieved in PBRs, with high removal rates at various concentrations.
- Optimal performance linked to biofilm acclimation and growth; mass transfer was not limiting.
- Nitrate presence significantly inhibited perchlorate reduction.
- Microbial community structure shifted along the reactor, with distinct populations at influent and effluent ends.
Conclusions:
- Sulfur-utilizing bacteria in PBRs are effective for perchlorate remediation.
- Biofilm development and acclimation are critical for efficient perchlorate removal.
- Reactor design and operating conditions, such as avoiding recirculation and managing nitrate, are important for successful bioremediation.
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