Defluoridation of Groundwater Using Electrocoagulation and Filtration: Efficiency and Energy Consumption.

Fluoride is a geogenic pollutant found in groundwater in several parts of the world. A possible treatment strategy for removing fluoride from groundwater to meet drinking water standards is the use of electrocoagulation (EC). EC has to be combined with filtration to meet drinking water standards for fluoride and turbidity. The objective of this study was to evaluate the use of iron (Fe) electrodes (mild steel) for defluoridation of groundwater using EC and filtration in continuous-flow mode. Different operating conditions were examined and included the use of baffles, varying flow rates, voltages, and different reactor configurations. The use of baffles was observed to increase removal efficiency. EC and filtration in continuous flow mode with Fe electrodes and no baffles gave a maximum removal efficiency of 36.2%. Addition of baffles improved efficiency to 42% with two baffles and 46.7% with one baffle; the difference between one versus two baffles was within analytical variability. The pH increased in all experiments indicating the need for neutralization after EC and filtration. The average energy consumed per unit volume was 4.73 Wh=L (or kWh=m3) in continuous-flow experiments. [ABSTRACT FROM AUTHOR]