Selenate removal in biofilm systems: Effect of nitrate and sulfate on selenium removal efficiency, biofilm structure and microbial community
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Details
| Original language | English |
|---|---|
| Pages (from-to) | 2380-2389 |
| Journal | Journal of Chemical Technology and Biotechnology |
| Volume | 93 |
| Issue number | 8 |
| Early online date | 1 Jan 2018 |
| DOIs | |
| Publication status | Published - Aug 2018 |
| Publication type | A1 Journal article-refereed |
Abstract
BACKGROUND: Selenium (Se) discharged into natural waterbodies can accumulate over time and have negative impacts on the environment. Se-laden wastewater streams can be treated using biological processes. However, the presence of other electron acceptors in wastewater, such as nitrate (NO3 -) and sulfate (SO4 2-), can influence selenate (SeO4 2-) reduction and impact the efficiency of biological treatment systems. RESULTS: SeO4 2- removal by biofilms formed from an anaerobic sludge inoculum was investigated in the presence of NO3 - and SO4 2- using drip flow reactors operated continuously for 10days at pH7.0 and 30°C. The highest total Se (∼60%) and SeO4 2- (∼80%) removal efficiencies were observed when the artificial wastewater contained SO4 2-. A maximum amount of 68μmol Se cm-2 was recovered from the biofilm matrix in SO4 2-+SeO4 2- exposed biofilms and biofilm mass was 2.7-fold increased for biofilms grown in the presence of SO4 2-. When SeO4 2- was the only electron acceptor, biofilms were thin and compact. In the simultaneous presence of NO3 - or SO4 2-, biofilms were thicker (> 0.6mm), less compact and exhibited gas pockets. CONCLUSION: The presence of SO4 2- had a beneficial effect on biofilm growth and the SeO4 2- removal efficiency, while the presence of NO3 - did not have a significant effect on SeO4 2- removal by the biofilms.
ASJC Scopus subject areas
Keywords
- Biofilm, Biofilm characterization, Co-electron acceptors, Nitrate, Selenate, Selenium removal, Sulfate