Laboratory of Microbial Ecology and Technology (LabMET), Ghent University, Coupure Links 653, B-9000 Gent, Belgium.
Environ Sci Technol. 2012 Nov 6;46(21):12209-16. doi: 10.1021/es3028154. Epub 2012 Oct 22.
Ammonia inhibition during anaerobic digestion limits the substrate loading rate and endangers process stability. Furthermore, digestates are interesting feedstocks for nutrient recovery. In this lab-scale study, an electrochemical cell was used to investigate the NH(4)(+) flux from anode to cathode. Under optimal conditions with synthetic wastewater, an NH(4)(+) charge transfer efficiency of 96% and NH(4)(+) flux of 120 g N m(-2) d(-1) could be obtained at a concomitant electricity input of 5 kWh kg(-1) N removed. A more selective NH(4)(+) transfer could be established by maintaining a high concentration of other cations in the cathode compartment. Comparable NH(4)(+) fluxes could be obtained with digestate at an electrical power input of 13 kWh kg(-1) N removed and 41% current efficiency. The ammonium level in the digestate could be lowered from 2.1 to 0.8 - 1.2 g N L(-1). Interestingly, also potassium fluxes of up to 241 g K(+) m(-2) d(-1) could be obtained at 23% current efficiency. As the cathode can be operated at high pH without the need for chemical addition, stripping and absorption of dissolved ammonia could reach 100% efficiency. By valorization of the generated side products, this technology shows economic potential for practical application.
在厌氧消化过程中氨抑制会限制基质的加载速率并危及过程稳定性。此外，消化物是营养物质回收的有趣原料。在这项实验室规模的研究中，使用电化学电池来研究从阳极到阴极的 NH(4)(+) 通量。在使用合成废水的最佳条件下，在去除 5 kWh kg(-1) N 时，可获得 96%的 NH(4)(+)电荷转移效率和 120 g N m(-2) d(-1)的 NH(4)(+)通量。通过在阴极室中保持其他阳离子的高浓度，可以建立更具选择性的 NH(4)(+)转移。在去除 13 kWh kg(-1) N 时，可获得 41%的电流效率，并且可获得类似的 NH(4)(+)通量。消化物中的铵水平可以从 2.1 降低到 0.8 - 1.2 g N L(-1)。有趣的是，在 23%的电流效率下，还可以获得高达 241 g K(+) m(-2) d(-1)的钾通量。由于阴极可以在高 pH 值下运行而无需添加化学物质，因此溶解氨的汽提和吸收可达到 100%的效率。通过利用生成的副产物，该技术显示出实际应用的经济潜力。
