Delft University of Technology, Faculty of Civil Engineering and Geosciences, Stevinweg 1, 2628, CN Delft, the Netherlands.
Delft University of Technology, Faculty of Civil Engineering and Geosciences, Stevinweg 1, 2628, CN Delft, the Netherlands.
Water Res. 2019 Oct 15;163:114856. doi: 10.1016/j.watres.2019.114856. Epub 2019 Jul 12.
Ammonium (NH) can be recovered from water for fertiliser production or even energy production purposes. Because NH recovery is more effective at increased concentrations, electrodialysis (ED) can be used to concentrate NH from side streams, such as sludge reject water, and simultaneously achieve high NH removal efficiencies. However, the effect of osmosis and back-diffusion increases when the NH concentration gradient between the diluate and the concentrate stream increases, resulting in a limitation of the concentration factor and an increase in energy consumption for NH removal. In this study, we showed that operation at dynamic current density (DCD) reduced the effect of osmosis and back-diffusion, due to a 75% decrease of the operational run time, compared to operation at a fixed current density (FCD). The concentration factor increased from 4.5 for an FCD to 6.7 for DCD, while the energy consumption of 90% NH removal from synthetic sludge reject water at DCD remained stable at 5.4 MJ·kg-N.
铵（NH）可以从水中回收，用于肥料生产甚至能源生产。因为 NH 回收在浓度增加时更有效，所以电渗析（ED）可用于浓缩来自侧流的 NH，例如污泥浓缩水，同时实现高 NH 去除效率。然而，当稀释液和浓缩液之间的 NH 浓度梯度增加时，渗透压和反向扩散的影响会增加，导致浓缩因子的限制和 NH 去除的能耗增加。在本研究中，我们表明，与固定电流密度（FCD）相比，动态电流密度（DCD）操作由于操作运行时间减少了 75%，因此降低了渗透压和反向扩散的影响。浓度因子从 FCD 的 4.5 增加到 DCD 的 6.7，而从合成污泥浓缩水中去除 90% NH 的能耗在 DCD 下仍稳定在 5.4 MJ·kg-N。
