Department of Environmental Engineering, College of Environmental and Resource Science, Zhejiang University, Hangzhou, China.
Department of Environmental Engineering, College of Environmental and Resource Science, Zhejiang University, Hangzhou, China; Zhejiang Province Key Lab Water Pollut Control & Envi, Zhejiang University, Hangzhou, Zhejiang, China.
Water Res. 2017 May 15;115:130-137. doi: 10.1016/j.watres.2017.03.003. Epub 2017 Mar 2.
The effects of nitrate (NO) on chromate (Cr(VI)) reduction in a membrane biofilm reactor (MBfR) were studied when CH was the sole electron donor supplied with a non-limiting delivery capacity. A high surface loading of NO gave significant and irreversible inhibition of Cr(VI) reduction. At a surface loading of 500 mg Cr/m-d, the Cr(VI)-removal percentage was 100% when NO was absent (Stage 1), but was dramatically lowered to < 25% with introduction of 280 mg N m-d NO (Stage 2). After ∼50 days operation in Stage 2, the Cr(VI) reduction recovered to only ∼70% in Stage 3, when NO was removed from the influent; thus, NO had a significant long-term inhibition effect on Cr(VI) reduction. Weighted PCoA and UniFrac analyses proved that the introduction of NO 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. The denitrifier Chitinophagaceae was enriched after the addition of NO, while Pelomonas became important when nitrate was removed, suggesting its potential role as a Cr(VI) reducer. Moreover, introducing NO 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.
当 CH 是唯一提供非限制输送能力的电子供体时，研究了硝酸盐 (NO) 对膜生物膜反应器 (MBfR) 中铬酸盐 (Cr(VI)) 还原的影响。高表面负荷的 NO 会对 Cr(VI) 还原产生显著且不可逆的抑制作用。在表面负荷为 500 mg Cr/m-d 的情况下，当不存在 NO 时（第 1 阶段），Cr(VI) 的去除率为 100%，但当引入 280 mg N m-d 的 NO 时（第 2 阶段），Cr(VI) 的去除率急剧下降至<25%。在第 2 阶段运行约 50 天后，当 NO 从进水口去除时，Cr(VI) 还原在第 3 阶段仅恢复到约 70%；因此，NO 对 Cr(VI) 还原具有显著的长期抑制作用。加权 PCoA 和 UniFrac 分析证明，NO 的引入对生物膜中的微生物群落产生了强烈影响，这种变化可能与 Cr(VI) 还原的不可逆抑制有关。例如，最初主要参与 Cr(VI) 还原的 Meiothermus 随着 NO 的引入而减少。添加 NO 后，脱氮菌 Chitinophagaceae 得到了富集，而硝酸盐去除后，Pelomonas 变得重要，表明其可能作为 Cr(VI) 还原剂发挥作用。此外，引入 NO 导致与铬酸盐还原相关的预测基因（通过 PICRUSt）数量减少，但预测与反硝化、甲烷氧化和发酵相关的基因增加。
