Ralph E. Martin Department of Chemical Engineering, University of Arkansas, 3202 Bell Engineering Center, Fayetteville AR 72701, United States; Department of Electrical and Computer Engineering, Concordia University, Center of Structural and Functional Genomics, 7141 Sherbrooke St. West, Montreal H4B 1R6, Canada.
Department of Agricultural Economics and Agribusiness, University of Arkansas, 217 Agriculture Building, Fayetteville, AR 72701, United States.
Water Res. 2022 Feb 15;210:118001. doi: 10.1016/j.watres.2021.118001. Epub 2021 Dec 23.
In this study, a suite of natural wastewater sources is tested to understand the effects of wastewater composition and source on electrochemically driven nitrogen and phosphorus nutrient removal. Kinetics, electrode behavior, and removal efficiency were evaluated during electrochemical precipitation, whereby a sacrificial magnesium (Mg) anode was used to drive precipitation of ammonium and phosphate. The electrochemical reactor demonstrated fast kinetics in the natural wastewater matrices, removing up to 54% of the phosphate present in natural wastewater within 1 min, with an energy input of only 0.04 kWh.m. After 1 min, phosphate removal followed a zero-order rate law in the 1 min - 30 min range. The zero-order rate constant (k) appears to depend upon differences in wastewater composition, where a faster rate constant is associated with higher Cl and NH concentrations, lower Ca concentrations, and higher organic carbon content. The sacrificial Mg anode showed the lowest corrosion resistance in the natural industrial wastewater source, with an increased corrosion rate (v) of 15.8 mm.y compared to 1.9-3.5 mm.y in municipal wastewater sources, while the Tafel slopes (β) showed a direct correlation with the natural wastewater composition and origin. An overall improvement of water quality was observed where important water quality parameters such as total organic carbon (TOC), total suspended solids (TSS), and turbidity showed a significant decrease. An economic analysis revealed costs based upon experimental Mg consumption are estimated to range from 0.19 $.m to 0.30 $.m, but costs based upon theoretical Mg consumption range from 0.09 $.m to 0.18 $.m. Overall, this study highlights that water chemistry parameters control nutrient recovery, while electrochemical treatment does not directly produce potable water, and that economic analysis should be based upon experimentally-determined Mg consumption data. Synopsis Statement: Magnesium-driven electrochemical precipitation of natural wastewater sources enables fast kinetics for phosphate removal at low energy input.
在这项研究中，测试了一系列天然废水来源，以了解废水成分和来源对电化学驱动的氮和磷营养物去除的影响。通过使用牺牲性镁 (Mg) 阳极来驱动铵和磷酸盐的沉淀，评估了电沉积过程中的动力学、电极行为和去除效率。在天然废水基质中，电化学反应器表现出快速的动力学，在 1 分钟内可去除天然废水中高达 54%的磷酸盐，输入能量仅为 0.04 kWh.m。在 1 分钟后，在 1 分钟至 30 分钟的范围内，磷酸盐的去除遵循零级速率定律。零级速率常数 (k) 似乎取决于废水成分的差异，其中较高的 Cl 和 NH 浓度、较低的 Ca 浓度和较高的有机碳含量与较快的速率常数相关。牺牲性 Mg 阳极在天然工业废水中表现出最低的耐腐蚀性，腐蚀速率 (v) 比市政废水源中的 1.9-3.5 mm.y 增加了 15.8 mm.y，而塔菲尔斜率 (β) 与天然废水组成和来源呈直接相关。观察到水质的整体改善，重要的水质参数如总有机碳 (TOC)、总悬浮固体 (TSS) 和浊度均显著降低。经济分析表明，基于实验性 Mg 消耗的成本估计范围为 0.19 美元/m 至 0.30 美元/m，但基于理论性 Mg 消耗的成本范围为 0.09 美元/m 至 0.18 美元/m。总体而言，这项研究强调了水化学参数控制营养物的回收，而电化学处理并不能直接生产饮用水，并且经济分析应基于实验确定的 Mg 消耗数据。
