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Nitrate effects on chromate reduction in a methane-based biofilm.
- Source :
-
Water Research . May2017, Vol. 115, p130-137. 8p. - Publication Year :
- 2017
-
Abstract
- The effects of nitrate (NO 3 − ) on chromate (Cr(VI)) reduction in a membrane biofilm reactor (MBfR) were studied when CH 4 was the sole electron donor supplied with a non-limiting delivery capacity. A high surface loading of NO 3 − gave significant and irreversible inhibition of Cr(VI) reduction. At a surface loading of 500 mg Cr/m 2 -d, the Cr(VI)-removal percentage was 100% when NO 3 − was absent (Stage 1), but was dramatically lowered to < 25% with introduction of 280 mg N m −2 -d NO 3 − (Stage 2). After ∼50 days operation in Stage 2, the Cr(VI) reduction recovered to only ∼70% in Stage 3, when NO 3 − was removed from the influent; thus, NO 3 − had a significant long-term inhibition effect on Cr(VI) reduction. Weighted PCoA and UniFrac analyses proved that the introduction of NO 3 − had a strong impact on the microbial community in the biofilms, and the changes possibly were linked to the irreversible inhibition of Cr(VI) reduction. For example, Meiothermus , the main genus involved in Cr(VI) reduction at first, declined with introduction of NO 3 − . The denitrifier Chitinophagaceae was enriched after the addition of NO 3 − , while Pelomonas became important when nitrate was removed, suggesting its potential role as a Cr(VI) reducer. Moreover, introducing NO 3 − led to a decrease in the number of genes predicted (by PICRUSt) to be related to chromate reduction, but genes predicted to be related to denitrification, methane oxidation, and fermentation increased. [ABSTRACT FROM AUTHOR]
- Subjects :
- *NITRATES
*CHROMATES reduction
*METHANE
*BIOFILMS
*PHYLOGENY
Subjects
Details
- Language :
- English
- ISSN :
- 00431354
- Volume :
- 115
- Database :
- Academic Search Index
- Journal :
- Water Research
- Publication Type :
- Academic Journal
- Accession number :
- 122154846
- Full Text :
- https://doi.org/10.1016/j.watres.2017.03.003