Feyereisen Gary W, Moorman Thomas B, Christianson Laura E, Venterea Rodney T, Coulter Jeffrey A, Tschirner Ulrike W
J Environ Qual. 2016 May;45(3):779-87. doi: 10.2134/jeq2015.07.0407.
Denitrifying bioreactors can be effective for removing nitrate from agricultural tile drainage; however, questions about cold springtime performance persist. The objective of this study was to improve the nitrate removal rate (NRR) of denitrifying bioreactors at warm and cold temperatures using agriculturally derived media rather than wood chips (WC). Corn ( L.) cobs (CC), corn stover (CS), barley ( L.) straw (BS), WC, and CC followed by a compartment of WC (CC+WC) were tested in laboratory columns for 5 mo at a 12-h hydraulic residence time in separate experiments at 15.5 and 1.5°C. Nitrate-N removal rates ranged from 35 to 1.4 at 15.5°C and from 7.4 to 1.6 g N m d at 1.5°C, respectively; NRRs were ranked CC > CC+WC > BS = CS > WC and CC ≥ CC+WC = CS ≥ BS > WC for 15.5 and 1.5°C, respectively. Although NRRs for CC were increased relative to WC, CC released greater amounts of carbon. Greater abundance of nitrous oxide (NO) reductase gene () was supported by crop residues than WC at 15.5°C, and CS and BS supported greater abundance than WC at 1.5°C. Production of NO relative to nitrate removal (NO) was consistently greater at 1.5°C (7.5% of nitrate removed) than at 15.5°C (1.9%). The NO was lowest in CC (1.1%) and CC-WC (0.9%) and greatest in WC (9.7%). Using a compartment of agricultural residue media in series before wood chips has the potential to improve denitrifying bioreactor nitrate removal rates, but field-scale verification is needed.
反硝化生物反应器对于去除农业瓦管排水中的硝酸盐可能是有效的；然而，关于其在寒冷春季性能的问题依然存在。本研究的目的是使用农业来源的介质而非木片，提高反硝化生物反应器在温暖和寒冷温度下的硝酸盐去除率（NRR）。在实验室柱中，分别在15.5℃和1.5℃下，以12小时的水力停留时间对玉米（L.）芯（CC）、玉米秸秆（CS）、大麦（L.）秸秆（BS）、木片（WC）以及先CC后接一个WC隔层（CC + WC）进行了5个月的测试。在15.5℃时，硝酸盐 - N去除率范围为35至1.4，在1.5℃时为7.4至1.6 g N m² d⁻¹；对于15.5℃和1.5℃，NRR排名分别为CC > CC + WC > BS = CS > WC以及CC ≥ CC + WC = CS ≥ BS > WC。尽管CC的NRR相对于WC有所提高，但CC释放出了更多的碳。在15.5℃时，作物残渣比WC支持更高丰度的一氧化二氮（N₂O）还原酶基因（），在1.5℃时，CS和BS比WC支持更高的丰度。相对于硝酸盐去除量（N₂O），N₂O的产生在1.5℃（去除硝酸盐的7.5%）时始终高于15.5℃（1.9%）。N₂O在CC（1.1%）和CC - WC（0.9%）中最低，在WC（9.7%）中最高。在木片之前串联使用一个农业残留介质隔层有提高反硝化生物反应器硝酸盐去除率的潜力，但需要进行实地规模验证。
