Elimination of chemical oxygen demand from domestic residual water by electrocoagulation with aluminum and iron electrodes

Abstract This research determined the efficiency of removal of chemical oxygen demand (COD) by an electrocoagulation process. An electrocoagulation reactor with aluminum and iron electrodes was used to treat water from the treatment plant of the Research Center for Wastewater Treatment and Hazardous Waste. The COD removal percentage was a response variable for the experimental factorial design. The factors influencing the process were current intensity, treatment time, and pH. The best results in the percentage of removal of the COD were very similar to that obtained at a pH of 8.2 and 7, with values of 83% and 84%, respectively, with a current intensity of 7 A and a treatment time of 15 min. However, at 5 A and 10 min, values that exceed 80% removal were obtained. Statistical analysis indicates that only current intensity and time were significant for the response variable. Electrocoagulation is a viable process for the treatment of this type of effluent, in addition to being more versatile compared with biological processes.

摘要 本研究探究了电絮凝法（electrocoagulation）去除化学需氧量（chemical oxygen demand, COD）的效能。本研究采用搭载铝、铁电极的电絮凝反应器，对来自废水处理与危险废物研究中心污水处理厂的水样进行处理。本实验采用析因实验设计，以COD去除率作为响应变量。影响该工艺的因素包括电流强度、处理时长与初始pH值。当电流强度为7 A、处理时长15分钟时，COD去除效果最优；此时在pH为8.2与7的工况下，COD去除率分别为83%与84%，二者去除效果相近。不过，当电流强度为5 A、处理时长10分钟时，同样可获得超过80%的COD去除率。统计分析结果显示，仅电流强度与处理时长对响应变量存在显著影响。相较于传统生物处理工艺，电絮凝法不仅可有效处理此类废水，且具备更高的工艺灵活性，是一种可行的废水处理方案。