Civil and Environmental Engineering Department, Amirkabir University of Technology (AUT), Hafez Ave., Tehran, 15875-4413, Iran.
Social Determinant of Health Research Center, Qazvin University of Medical Sciences, Qazvin, Iran.
J Environ Manage. 2019 Jan 15;230:245-254. doi: 10.1016/j.jenvman.2018.09.091. Epub 2018 Oct 3.
This study aims to investigate the effects of alternating current (AC) and direct current (DC) for nitrate removal and its operating costs by using a continuous electrocoagulation (CEC) process. For this purpose, two series of 31 experiments, which were designed by response surface method (RSM), were carried out in both cases of the AC and the DC modes. In each series, the effect of selected parameters, namely, initial nitrate concentration, inlet flow rate, current density and initial pH along with their interactions on the nitrate removal efficiency as well as its operating costs, as responses, were investigated separately. According to the analysis of variance (ANOVA), there is a reasonable agreement between achieving results and the experimental data for both responses. The nitrate removal in the AC mode was slightly more efficient than that of the DC mode. In addition, the average operating costs of the DC mode, including the energy and the electrode consumption for the CEC process were achieved 54 US$/(kg nitrate removed); whereas this amount was calculated 29 US$/(kg nitrate removed) for the AC mode. Therefore, the average of the operating costs was improved more than 40% using the AC mode, which was mainly related to reduction of aluminum electrode consumption.
本研究旨在通过连续电凝（CEC）工艺，利用交流电（AC）和直流电（DC）研究硝酸盐去除及其运行成本的影响。为此，在 AC 和 DC 两种模式下，分别设计了两组共 31 个实验，每组实验都通过响应面法（RSM）进行。在每个系列中，分别研究了选定参数（即初始硝酸盐浓度、入口流速、电流密度和初始 pH 值及其相互作用）对硝酸盐去除效率及其运行成本这两个响应的影响。根据方差分析（ANOVA），这两个响应的实验结果和预测结果之间具有较好的一致性。在 AC 模式下，硝酸盐的去除效率略高于 DC 模式。此外，对于直流电模式，包括电能和 CEC 工艺的电极消耗在内的平均运行成本为 54 美元/（kg 硝酸盐去除）；而对于交流电模式，这一数值为 29 美元/（kg 硝酸盐去除）。因此，交流电模式的运行成本平均提高了 40%以上，这主要与铝电极消耗的减少有关。
