Fisheries College, Ocean University of China, Qingdao, 266001, China; School of Environment, Tsinghua University, Beijing, 100084, China.
Fisheries College, Ocean University of China, Qingdao, 266001, China.
Chemosphere. 2020 Mar;243:125342. doi: 10.1016/j.chemosphere.2019.125342. Epub 2019 Nov 16.
This study investigated an alternative carbon source derived from maize cobs (MCs) to enhance nitrogen removal in saline constructed wetlands (SCWs). The main objectives were to select the proper pretreatment method of MCs for rapid carbon release; and to investigate the effects of maize cob pieces (i.e. MCP) and three addition levels of maize cob lixiviums (i.e. L-MCL, M-MCL and H-MCL) on nitrogen purification performance and microbial characteristics of SCWs. Results showed NaOH pretreatment enhanced carbon release of MCs in seawater (from 7.5 ± 0.4 mg g to 16.4 ± 0.2 mg g). The 80-d trial showed SCWs with M-MCL addition performed well on nitrogen removal: NO-N, 88.8 ± 11.6%; NO-N, 91.1 ± 3.5%; TAN, 96.5 ± 1.6%; TIN, 89.8 ± 10.4%; with 2 mg L effluent COD. Denitrification parameters confirmed MCL to be a high quality carbon source: denitrification potential (P) = 0.16 g g; heterotrophy anoxic yield coefficient (Y) = 0.54 g g. The MCP and H-MCL treatments improved substrate dehydrogenase activity, indicating a higher microbial activity in these SCWs. Sequencing analysis revealed that, regardless of addition manners, carbon sources from MCs changed the rhizosphere microbial community. At genus level, Anaerophaga (10.1%), Granulosicoccus (8.2%) and Sulfurimonas (6.6%) dominated in SCWs under MCP treatment. Increased MCL addition levels improved the relative abundance of Vibrio, Malonomonas and Caldithrix, suggesting the enhancement of denitrification. Relative high proportions of Desulfotignum and Desulfovibrio, and Sulfurimonas were observed in MCP and H-MCL SCWs, implying that sulfate reduction occurred in SCWs with excess carbon sources.
本研究考察了一种源自玉米芯（MCs）的替代碳源，以增强盐度人工湿地（SCWs）中的氮去除。主要目标是选择合适的 MCs 预处理方法以实现快速碳释放；并研究玉米芯块（即 MCP）和三种玉米芯浸提液添加水平（即 L-MCL、M-MCL 和 H-MCL）对 SCWs 氮净化性能和微生物特性的影响。结果表明，NaOH 预处理增强了 MCs 在海水中的碳释放（从 7.5±0.4 mg g 增加到 16.4±0.2 mg g）。80 天试验表明，添加 M-MCL 的 SCWs 在氮去除方面表现良好：NO-N，88.8±11.6%；NO-N，91.1±3.5%；TAN，96.5±1.6%；TIN，89.8±10.4%；出水 COD 为 2 mg L。反硝化参数证实 MCL 是一种高质量的碳源：反硝化潜力（P）=0.16 g g；异养缺氧产率系数（Y）=0.54 g g。MCP 和 H-MCL 处理提高了基质脱氢酶活性，表明这些 SCWs 中的微生物活性更高。测序分析表明，无论添加方式如何，来自 MCs 的碳源改变了根际微生物群落。在属水平上，Anaerophaga（10.1%）、Granulosicoccus（8.2%）和 Sulfurimonas（6.6%）在 MCP 处理下的 SCWs 中占主导地位。增加 MCL 添加水平提高了 Vibrio、Malonomonas 和 Caldithrix 的相对丰度，表明反硝化作用增强。在 MCP 和 H-MCL SCWs 中观察到相对较高比例的 Desulfotignum 和 Desulfovibrio 和 Sulfurimonas，表明在含有过量碳源的 SCWs 中发生了硫酸盐还原。
