Widespread groundwater pollution with nitrate (NO₃⁻) and the finite and decreasing geogenic NO₃⁻ degradation capacity in aquifers require a better understanding of potential treatment methods. This project aimed at exploring and comparing the efficiency of four organic substances as electron donors for heterotrophic denitrification. Circulation column experiments using sediment without NO₃⁻ degradation capacity and high agricultural NO₃⁻ groundwater were conducted. Acetate, glucose, ascorbic acid, and ethanol were added to these columns in three concentration steps to induce biological denitrification, whereby also temperature dependence of denitrification rates (room temperature and typical groundwater temperature of 10°C) was taken into account. Results show denitrification with all four carbon (C) sources with intensities varying considerably between electron donors. Comparison of the two temperature approaches shows substantial differences between applied organic substances and indicates T as an important variable for denitrification. Ethanol is clearly the most effective electron donor for biodenitrification in groundwater investigated in this study, with a stronger and more effective NO₃⁻ degradation at 10°C than at room temperature. In contrast, much higher reaction rates are achieved with glucose at room temperature, compared to 10°C. Denitrification with ascorbic acid is very low at both temperatures; its addition produces biomass which repeatedly led to column clogging. In the entire test series, nitrite (NO₂⁻) accumulation occurred more frequently and in higher concentrations at 10°C. Analysis of microorganisms shows a strong modification in microbial community in reaction to the addition of different organic C as well as between the two temperature approaches.

中文翻译：

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各种有机物质引起的反硝化作用的比较——反应速率、微生物学和温度效应

硝酸盐 (NO ₃ ^- )造成的广泛地下水污染以及含水层中有限且不断下降的地质成因 NO ₃ ^-降解能力需要更好地了解潜在的处理方法。该项目旨在探索和比较四种有机物质作为异养反硝化电子供体的效率。使用不含NO ₃ ^-降解能力和高农业NO ₃ ^-沉积物的循环柱实验进行了地下水。将乙酸盐、葡萄糖、抗坏血酸和乙醇分三个浓缩步骤添加到这些柱子中以诱导生物反硝化，其中还考虑了反硝化速率的温度依赖性（室温和 10°C 的典型地下水温度）。结果显示，所有四种碳 (C) 源的反硝化作用强度在电子供体之间差异很大。两种温度方法的比较显示应用的有机物质之间存在显着差异，并表明T作为反硝化的重要变量。乙醇显然是本研究中调查的地下水生物脱氮作用最有效的电子供体，具有更强、更有效的 NO ₃ ^-10°C 比室温降解。相比之下，与 10°C 相比，在室温下使用葡萄糖可实现更高的反应速率。在这两种温度下，抗坏血酸的反硝化作用都非常低；它的添加会产生生物质，反复导致色谱柱堵塞。在整个测试系列中，亚硝酸盐 (NO ₂ ^- ) 在 10°C 下发生的频率更高且浓度更高。对微生物的分析表明，由于添加不同的有机碳以及两种温度方法之间的差异，微生物群落发生了强烈的改变。