Kampman Christel, Piai Laura, Temmink Hardy, Hendrickx Tim L G, Zeeman Grietje, Buisman Cees J N
Sub-department of Environmental Technology, Wageningen University, P.O. Box 17, 6700 AA Wageningen, The Netherlands E-mail:
Water Sci Technol. 2018 Jun;77(11-12):2589-2597. doi: 10.2166/wst.2018.219.
Chemical energy can be recovered from municipal wastewater as biogas through anaerobic treatment. Effluent from direct anaerobic wastewater treatment at low temperatures, however, still contains ammonium and considerable amounts of dissolved methane. After nitritation, methane can be used as electron donor for denitrification by the anaerobic bacterium 'Candidatus Methylomirabilis oxyfera'. It was shown that in the presence of 0.7% O denitrifying methanotrophic activity slightly increased and returned to its original level after oxygen had been removed. At 1.1% O, methane consumption rate increased 118%, nitrite consumption rate increased 58%. After removal of oxygen, methane consumption rate fully recovered, and nitrite consumption rate returned to 88%. Therefore, traces of oxygen that bacteria are likely to be exposed to in wastewater treatment are not expected to negatively affect the denitrifying methanotrophic process. 2.0% O inhibited denitrifying activity. Nitrite consumption rate decreased 60% and did not recover after removal of oxygen. No clear effect on methane consumption was observed. Further studies should evaluate if intermittent addition of oxygen results in increased growth rates of the slow-growing 'Candidatus Methylomirabilis oxyfera'.
化学能可通过厌氧处理从城市废水中作为沼气回收。然而，低温下直接厌氧废水处理的出水仍含有铵和大量溶解的甲烷。亚硝化后，甲烷可被厌氧细菌“食甲基菌属嗜氧亚种（Candidatus Methylomirabilis oxyfera）”用作反硝化的电子供体。结果表明，在存在0.7%氧气的情况下，反硝化甲烷氧化活性略有增加，并在去除氧气后恢复到原始水平。在1.1%氧气存在下，甲烷消耗率增加了118%，亚硝酸盐消耗率增加了58%。去除氧气后，甲烷消耗率完全恢复，亚硝酸盐消耗率恢复到88%。因此，预计废水处理中细菌可能接触到的微量氧气不会对反硝化甲烷氧化过程产生负面影响。2.0%的氧气抑制了反硝化活性。亚硝酸盐消耗率下降了60%，去除氧气后未恢复。未观察到对甲烷消耗有明显影响。进一步的研究应评估间歇性添加氧气是否会导致生长缓慢的“食甲基菌属嗜氧亚种（Candidatus Methylomirabilis oxyfera）”的生长速率增加。
