Export of Dissolved Methane and Carbon Dioxide with Effluents from Municipal Wastewater Treatment Plants

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• 作者：Zeyad Alshboul ; Jorge Encinas-Fernández ; Hilmar Hofmann ; Andreas Lorke
• 刊名：Environmental Science & Technology
• 出版年：2016
• 出版时间：June 7, 2016
• 年：2016
• 卷：50
• 期：11
• 页码：5555-5563
• 全文大小：458K
• 年卷期：0
• ISSN：1520-5851

文摘

Inland waters play an important role for regional and global scale carbon cycling and are significant sources of the atmospheric greenhouse gases methane (CH₄) and carbon dioxide (CO₂). Although most studies considered the input of terrestrially derived organic and inorganic carbon as the main sources for these emissions, anthropogenic sources have rarely been investigated. Municipal wastewater treatment plants (WWTPs) could be additional sources of carbon by discharging the treated wastewater into the surrounding aquatic ecosystems. Here we analyze seasonally resolved measurements of dissolved CH₄ and CO₂ concentrations in effluents and receiving streams at nine WWTPs in Germany. We found that effluent addition significantly altered the physicochemical properties of the streamwater. Downstream of the WWTPs, the concentrations of dissolved CH₄ and CO₂ were enhanced and the atmospheric fluxes of both gases increased by a factor of 1.2 and 8.6, respectively. The CH₄ exported with discharged effluent, however, accounted for only a negligible fraction (0.02%) of the estimated total CH₄ emissions during the treatment process. The CH₄ concentration in the effluent water was linearly related to the organic load of the wastewater, which can provide an empirical basis for future attempts to add WWTPs inputs to regional-scale models for inland water–carbon fluxes.