Modin Oskar
a Division of Water Environment Technology, Department of Architecture and Civil Engineering , Chalmers University of Technology , Gothenburg , Sweden.
Environ Technol. 2018 May;39(9):1217-1225. doi: 10.1080/09593330.2017.1323961. Epub 2017 May 11.
Aerobic methanotrophic bacteria use methane as their only source of energy and carbon. They release organic compounds that can serve as electron donors for co-existing denitrifiers. This interaction between methanotrophs and denitrifiers is known to contribute to nitrogen losses in natural environments and has also been exploited by researchers for denitrification of nitrate-contaminated wastewater. The purpose of this study was to develop a mathematical model describing aerobic methane oxidation coupled to denitrification in suspended-growth reactors. The model considered the activities of three microbial groups: aerobic methanotrophs, facultative methylotrophs, and facultative heterotrophs. The model was tested against data from the scientific literature and used to explore the effects of the oxygen mass transfer coefficient, the solids retention time, and the fraction methane in the feed gas on nitrate removal. The fraction of methane in the feed gas was found to be critical for the nitrate removal rate. A value of about 15% in air was optimal. A lower methane fraction led to excess oxygen, which was detrimental for denitrification. A higher fraction led to oxygen-limitation, which restricted the growth rate of methanotrophs in the reactor.
好氧甲烷氧化细菌以甲烷作为其唯一的能量和碳源。它们释放的有机化合物可以作为共存反硝化细菌的电子供体。已知甲烷氧化菌和反硝化细菌之间的这种相互作用会导致自然环境中的氮损失，并且研究人员也利用这种相互作用对硝酸盐污染的废水进行反硝化处理。本研究的目的是建立一个数学模型，描述悬浮生长反应器中耦合反硝化的好氧甲烷氧化过程。该模型考虑了三类微生物的活性：好氧甲烷氧化菌、兼性甲基营养菌和兼性异养菌。该模型根据科学文献中的数据进行了测试，并用于探讨氧气传质系数、固体停留时间和进料气中甲烷分数对硝酸盐去除的影响。发现进料气中甲烷的分数对硝酸盐去除率至关重要。空气中约15% 的值是最佳的。较低的甲烷分数会导致氧气过剩，这对反硝化不利。较高的分数会导致氧气限制，从而限制反应器中甲烷氧化菌的生长速率。
