Electrochemical Nutrient Recovery Enables Ammonia Toxicity Control and Biogas Desulfurization in Anaerobic Digestion

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• 作者：Joachim Desloover ; Jo De Vrieze ; Maarten Van de Vijver ; Jacky Mortelmans ; Ren茅 Rozendal ; Korneel Rabaey
• 刊名：Environmental Science & Technology
• 出版年：2015
• 出版时间：January 20, 2015
• 年：2015
• 卷：49
• 期：2
• 页码：948-955
• 全文大小：352K
• ISSN：1520-5851

文摘

Organic waste streams can be valorized and reduced in volume with anaerobic digestion (AD). An often-encountered key issue however is the high ammonium (NH₄⁺) content of certain waste streams. Ammonia (NH₃), in equilibrium with NH₄⁺, is a toxic compound to the methanogenic community, which limits the organic loading rate and endangers process stability. An electrochemical system (ES) linked to a digester could, besides recovering this nutrient, decrease NH₃ toxicity through electrochemical extraction. Therefore, two digesters with and without ES attached in the recirculation loop were operated to test whether the ES could control NH₃ toxicity. During periods of high ammonium loading rates, the methane (CH₄) production of the ES-coupled reactor was up to 4.5 times higher compared to the control, which could be explained through simultaneous NH₄⁺ extraction and electrochemical pH control. A nitrogen flux of 47 g N m^鈥? membrane d^鈥? could be obtained in the ES-coupled reactor, resulting in a current and removal efficiency of 38 卤 5% and 28 卤 2%, respectively, at an electrochemical power input of 17 卤 2 kWh kg^鈥? N. The anode also oxidized sulfide, resulting in a significantly lower H₂S emission via the biogas. Lastly, limited methanogenic community dynamics pointed to a nonselective influence of the different operational conditions.