Production of Nitrous Oxide from Nitrite in Stable Type II Methanotrophic Enrichments

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• 作者：Jaewook Myung ; Zhiyue Wang ; Tong Yuan ; Ping Zhang ; Joy D. Van Nostrand ; Jizhong Zhou ; Craig S. Criddle
• 刊名：Environmental Science & Technology
• 出版年：2015
• 出版时间：September 15, 2015
• 年：2015
• 卷：49
• 期：18
• 页码：10969-10975
• 全文大小：378K
• ISSN：1520-5851

文摘

The coupled aerobic鈥揳noxic nitrous decomposition operation is a new process for wastewater treatment that removes nitrogen from wastewater and recovers energy from the nitrogen in three steps: (1) NH₄⁺ oxidation to NO₂^{鈥?/sup>, (2) NO₂鈥?/sup> reduction to N₂O, and (3) N₂O conversion to N₂ with energy production. Here, we demonstrate that type II methanotrophic enrichments can mediate step two by coupling oxidation of poly(3-hydroxybutyrate) (P3HB) to NO₂鈥?/sup> reduction. Enrichments grown with NH₄+ and NO₂鈥?/sup> were subject to alternating 48-h aerobic and anoxic periods, in which CH₄ and NO₂鈥?/sup> were added together in a 鈥渃oupled鈥?mode of operation or separately in a 鈥渄ecoupled mode鈥? Community structure was stable in both modes and dominated by Methylocystis. In the coupled mode, production of P3HB and N₂O was low. In the decoupled mode, significant P3HB was produced, and oxidation of P3HB drove reduction of NO₂鈥?/sup> to N₂O with 鈭?0% conversion for >30 cycles (120 d). In batch tests of wasted cells from the decoupled mode, N₂O production rates increased at low O₂ or high NO₂鈥?/sup> levels. The results are significant for the development of engineered processes that remove nitrogen from wastewater and for understanding of conditions that favor environmental production of N₂O.}