Contribution of Liquid/Gas Mass-Transfer Limitations to Dissolved Methane Oversaturation in Anaerobic Treatment of Dilute Wastewater

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• 作者：Hyeongu Yeo ; Junyeong An ; Robertson Reid ; Bruce E. Rittmann ; Hyung-Sool Lee
• 刊名：Environmental Science & Technology
• 出版年：2015
• 出版时间：September 1, 2015
• 年：2015
• 卷：49
• 期：17
• 页码：10366-10372
• 全文大小：340K
• ISSN：1520-5851

文摘

The mechanisms controlling the accumulation of dissolved methane in anaerobic membrane bioreactors (AnMBRs) treating a synthetic dilute wastewater (a glucose medium) were assessed experimentally and theoretically. The AnMBR was maintained at a temperature of 24鈥?6 掳C as the organic loading rate increased from 0.39 to 1.1 kg COD/m³-d. The measured concentration of dissolved methane was consistently 2.2- to 2.5-fold larger than the concentration of dissolved methane at thermodynamic equilibrium with the measured CH₄ partial pressure, and the fraction of dissolved methane was as high as 76% of the total methane produced. The low gas production rate in the AnMBR significantly slowed the mass transport of dissolved methane to the gas phase. Although the production rate of total methane increased linearly with the COD loading rate, the concentration of dissolved methane only slightly increased with an increasing organic loading rate, because the mass-transfer rate increased by almost 5-fold as the COD loading increased from 0.39 to 1.1 kg COD/m³-d. Thus, slow mass transport kinetics exacerbated the situation in which dissolved methane accounted for a substantial fraction of the total methane generated from the AnMBR.