Isotopomer Analysis of Production and Consumption Mechanisms of N2O and CH4 in an Advanced Wastewater Treatment System
- 21 December 2010
- journal article
- research article
- Published by American Chemical Society (ACS) in Environmental Science & Technology
- Vol. 45 (3), 917-922
- https://doi.org/10.1021/es102985u
Abstract
Wastewater treatment processes are believed to be anthropogenic sources of nitrous oxide (N2O) and methane (CH4). However, few studies have examined the mechanisms and controlling factors in production of these greenhouse gases in complex bacterial systems. To elucidate production and consumption mechanisms of N2O and CH4 in microbial consortia during wastewater treatment and to characterize human waste sources, we measured their concentrations and isotopomer ratios (elemental isotope ratios and site-specific N isotope ratios in asymmetric molecules of NNO) in water and gas samples collected by an advanced treatment system in Tokyo. Although the estimated emissions of N2O and CH4 from the system were found to be lower than those from the typical treatment systems reported before, water in biological reaction tanks was supersaturated with both gases. The concentration of N2O, produced mainly by nitrifier-denitrification as indicated by isotopomer ratios, was highest in the oxic tank (ca. 4000% saturation). The dissolved CH4 concentration was highest in in-flow water (ca. 3000% saturation). It decreased gradually during treatment. Its carbon isotope ratio indicated that the decrease resulted from bacterial CH4 oxidation and that microbial CH4 production can occur in anaerobic and settling tanks.This publication has 31 references indexed in Scilit:
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