Process Performance Combining Natural Coagulant Moringa oleifera Lam and Ultrafiltration for Groundwater Defluoridation

Abstract

The reduction of the excess fluoride present in groundwater and surface water is of paramount importance to the public supply, given that its excess can trigger various harmful effects on human health, such as dental and skeletal fluorosis. In this context, the objective of the present investigation was to evaluate the defluoridation of groundwater using coagulation/flocculation/sedimentation (C/F/S) process using the natural coagulant Moringa oleifera Lam (MO) followed by ultrafiltration membrane process. C/F/S tests were carried out in a Jar test apparatus with different concentrations of the coagulant and subsequent ultrafiltration in a membrane module. The tests used different initial fluoride concentrations, coagulant dosages, and water samples (distilled, ground, and surface water). Fluoride removal was most effective using 5 ppm of fluoride initial concentration and 5 g/L of MO coagulant dosage; however, an increase in turbidity was observed. The ultrafiltration step was used to improve water quality parameters, and at a pressure of 2 bar, it was obtained 97% of turbidity and color removal and 83% of fluoride removal. Thus, the results obtained applying the combined process of C/F/S followed by ultrafiltration can be considered a promising alternative to defluoridation of groundwater intended for public supply.