College of New Energy and Environment, Jilin University, Changchun 130021, People's Republic of China; Key Lab of Groundwater Resources and Environment, Ministry of Education, Jilin University, Changchun 130021, People's Republic of China; Jilin Provincial Key Laboratory of Water Resources and Environment, Jilin University, Changchun 130021, People's Republic of China.
College of New Energy and Environment, Jilin University, Changchun 130021, People's Republic of China; Key Lab of Groundwater Resources and Environment, Ministry of Education, Jilin University, Changchun 130021, People's Republic of China; Jilin Provincial Key Laboratory of Water Resources and Environment, Jilin University, Changchun 130021, People's Republic of China; Institute of Water Resources and Environment, Jilin University, Changchun 130021, People's Republic of China.
Environ Pollut. 2019 Nov;254(Pt B):113053. doi: 10.1016/j.envpol.2019.113053. Epub 2019 Aug 14.
To investigate the removal characteristics of ammonium-nitrogen (NH-N), nitrite-nitrogen (NO-N), nitrate-nitrogen (NO-N), and total nitrogen from groundwater by a degradable composite active medium, kinetics, thermodynamics, and equilibrium adsorption, experiments were performed using scoria and degrading bacteria immobilized on scoria. Removal of NH-N, NO-N, and NO-N was conducted in adsorption experiments using different times, initial concentrations, pH values, and groundwater chemical compositions (Ca, Mg, HCO, CO, Fe, Mn, and SO). The results showed that the removal of nitrogen by the composite active medium was obviously better than that of scoria alone. The removal rates of NH-N (C = 5 mg/L), NO-N (C = 5 mg/L), and NO-N (C = 100 mg/L) by the composite active medium within 1 h were 96.05%, 82.40%, and 83.16%, respectively. The adsorption kinetics were well fitted to a pseudo-second order model, whereas the equilibrium adsorption agreed with the Freundlich model. With changes in the pH, variation in the removal could be attributed to the combined effect of hydrolysis and competitive ion adsorption, and the optimum pH was 7. Different concentration conditions, hardness, alkalinity, anions, and cations showed different promoting and inhibiting effects on the removal of nitrogen. A careful examination of ionic concentrations in adsorption batch experiments suggested that the sorption behavior of nitrogen onto the immobilized medium was mainly controlled by ion exchange. The degrading bacteria on the scoria surface were eluted and analyzed by metagenomic sequencing. There were significant differences in the number of operational taxons, relative abundances, and community diversity among degrading bacteria after adsorption of the three forms of nitrogen. The relative abundance of degrading bacteria was highest after NO-N removal, and the diversity was highest after NO-N removal. Pseudomonas and Serratia were the dominant genera that could efficiently remove NH-N and NO-N.
为了研究可降解复合活性介质对地下水氨氮（NH-N）、亚硝态氮（NO-N）、硝态氮（NO-N）和总氮的去除特性，进行了动力学、热力学和平衡吸附实验，使用火山渣和固定在火山渣上的降解细菌。通过不同的时间、初始浓度、pH 值和地下水化学成分（Ca、Mg、HCO、CO、Fe、Mn 和 SO）进行吸附实验，去除 NH-N、NO-N 和 NO-N。结果表明，复合活性介质对氮的去除明显优于单独的火山渣。在 1 h 内，复合活性介质对 NH-N（C=5 mg/L）、NO-N（C=5 mg/L）和 NO-N（C=100 mg/L）的去除率分别为 96.05%、82.40%和 83.16%。吸附动力学很好地符合准二级模型，而平衡吸附符合 Freundlich 模型。随着 pH 值的变化，去除率的变化可以归因于水解和竞争离子吸附的综合影响，最佳 pH 值为 7。不同浓度条件、硬度、碱度、阴离子和阳离子对氮的去除有不同的促进和抑制作用。对吸附批实验中离子浓度的仔细考察表明，氮在固定化介质上的吸附行为主要受离子交换控制。用火山渣表面的降解细菌进行洗脱和宏基因组测序分析。在吸附三种形式的氮后，降解细菌的操作分类单元数、相对丰度和群落多样性有显著差异。在去除 NO-N 后，降解细菌的相对丰度最高，在去除 NO-N 后，多样性最高。假单胞菌和沙雷氏菌是能够有效去除 NH-N 和 NO-N 的优势属。
