Department of Chemistry, University of Rome Sapienza, Piazzale Aldo Moro 5, 00185 Rome, Italy.
Molecules. 2020 Jun 12;25(12):2723. doi: 10.3390/molecules25122723.
Here, a 12-liter tubular microbial electrolysis cell (MEC) was developed as a post treatment unit for simultaneous biogas upgrading and ammonium recovery from the liquid effluent of an anaerobic digestion process. The MEC configuration adopted a cation exchange membrane to separate the inner anodic chamber and the external cathodic chamber, which were filled with graphite granules. The cathodic chamber performed the CO removal through the bioelectromethanogenesis reaction and alkalinity generation while the anodic oxidation of a synthetic fermentate partially sustained the energy demand of the process. Three different nitrogen load rates (73, 365, and 2229 mg N/Ld) were applied to the inner anodic chamber to test the performances of the whole process in terms of COD (Chemical Oxygen Demand) removal, CO removal, and nitrogen recovery. By maintaining the organic load rate at 2.55 g COD/Ld and the anodic chamber polarization at +0.2 V vs. SHE (Standard Hydrogen Electrode), the increase of the nitrogen load rate promoted the ammonium migration and recovery, i.e., the percentage of current counterbalanced by the ammonium migration increased from 1% to 100% by increasing the nitrogen load rate by 30-fold. The CO removal slightly increased during the three periods, and permitted the removal of 65% of the influent CO, which corresponded to an average removal of 2.2 g CO/Ld. During the operation with the higher nitrogen load rate, the MEC energy consumption, which was simultaneously used for the different operations, was lower than the selected benchmark technologies, i.e., 0.47 kW/N·m for CO removal and 0.88 kW·h/kg COD for COD oxidation were consumed by the MEC while the ammonium nitrogen recovery consumed 2.3 kW·h/kg N.
在这里，开发了一种 12 升管状微生物电解池 (MEC) 作为后处理单元，用于从厌氧消化过程的液体流出物中同时进行沼气升级和铵回收。MEC 配置采用阳离子交换膜将内部阳极室和外部阴极室分开，内部阳极室和外部阴极室填充石墨颗粒。阴极室通过生物电甲烷生成反应和碱度生成去除 CO，而合成发酵液的阳极氧化部分维持了过程的能量需求。将三个不同的氮负荷率（73、365 和 2229 mg N/Ld）应用于内部阳极室，以测试整个过程在 COD（化学需氧量）去除、CO 去除和氮回收方面的性能。通过将有机负荷率保持在 2.55 g COD/Ld 和阳极室极化在+0.2 V 相对于 SHE（标准氢电极），氮负荷率的增加促进了铵的迁移和回收，即通过将氮负荷率增加 30 倍，由铵迁移平衡的电流百分比从 1%增加到 100%。在三个时期内，CO 去除率略有增加，允许去除 65%的进水 CO，平均去除 2.2 g CO/Ld。在高氮负荷率下运行时，MEC 的能耗（同时用于不同操作）低于选定的基准技术，即 CO 去除消耗 0.47 kW/N·m，COD 氧化消耗 0.88 kW·h/kg COD，而铵氮回收消耗 2.3 kW·h/kg N。
