Read-Daily B L, Sabba F, Pavissich J P, Nerenberg R
Department of Engineering and Physics, Elizabethtown College, Elizabethtown, PA, 17022, USA.
Department of Civil Engineering and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA.
AMB Express. 2016 Dec;6(1):85. doi: 10.1186/s13568-016-0258-0. Epub 2016 Oct 3.
Nitrous oxide (NO) is a powerful greenhouse gas emitted from wastewater treatment, as well as natural systems, as a result of biological nitrification and denitrification. While denitrifying bacteria can be a significant source of NO, they can also reduce NO to N. More information on the kinetics of NO formation and reduction by denitrifying bacteria is needed to predict and quantify their impact on NO emissions. In this study, kinetic parameters were determined for Paracoccus pantotrophus, a common denitrifying bacterium. Parameters included the maximum specific reduction rates, [Formula: see text], growth rates, [Formula: see text], and yields, Y, for reduction of NO (nitrate) to nitrite (NO), NO to NO, and NO to N, with acetate as the electron donor. The [Formula: see text] values were 2.9 gN gCOD d for NO to NO, 1.4 gN gCOD d for NO to NO, and 5.3 gN gCOD d for NO to N. The [Formula: see text] values were 2.7, 0.93, and 1.5 d, respectively. When NO and NO were added concurrently, the apparent (extant) kinetics, [Formula: see text], assuming reduction to N, were 6.3 gCOD gCOD d, compared to 5.4 gCOD gCOD d for NO as the sole added acceptor. The [Formula: see text] was 1.6 d, compared to 2.5 d for NO alone. These results suggest that NO and NO were reduced concurrently. Based on this research, denitrifying bacteria like P. pantotrophus may serve as a significant sink for NO. With careful design and operation, treatment plants can use denitrifying bacteria to minimize NO emissions.
一氧化二氮（NO）是废水处理以及自然系统中因生物硝化和反硝化作用而排放的一种强效温室气体。虽然反硝化细菌可能是NO的重要来源，但它们也能将NO还原为N。需要更多关于反硝化细菌形成和还原NO的动力学信息，以预测和量化它们对NO排放的影响。在本研究中，测定了常见反硝化细菌嗜糖假单胞菌的动力学参数。参数包括以乙酸盐作为电子供体，将NO（硝酸盐）还原为亚硝酸盐（NO）、将NO还原为NO以及将NO还原为N时的最大比还原速率、生长速率和产率Y。将NO还原为NO时的最大比还原速率值为2.9 gN gCOD d，将NO还原为NO时为1.4 gN gCOD d，将NO还原为N时为5.3 gN gCOD d。生长速率值分别为2.7、0.93和1.5 d。当同时添加NO和NO时，假设还原为N的表观（现存）动力学最大比还原速率为6.3 gCOD gCOD d，而以NO作为唯一添加受体时为5.4 gCOD gCOD d。生长速率为1.6 d，而单独添加NO时为2.5 d。这些结果表明NO和NO是同时被还原的。基于这项研究，像嗜糖假单胞菌这样的反硝化细菌可能是NO的重要汇。通过精心设计和运行，污水处理厂可以利用反硝化细菌将NO排放降至最低。
