Aquatic humic substances, iron and manganese removal by ultrafiltration and nanofiltration membranes combined with coagulation-flocculation- sedimentation

Surface water and groundwater sources for human supply require treatment to remove substances that can cause human diseases and rejection. Aquatic humic substances, such as iron and manganese, interfere with the aesthetic and sanitary quality of the water because they cause color, odor and taste unpleasant. In addition, humic substances can form trihalomethanes which are serious harmful substances [1]. Aquatic humic substances are heterogeneous organic materials, resultant of the microbiological degradation of vegetable and animal residues, which can be produced in situ or transported by rain by percolating the soil [1] [2]. In water, iron and manganese can be found as its reduced forms under anoxic conditions [1] or forming complexes with humic matter [3] [4]. The presence of carboxylic and fenolic groups in the humic substances, enables their complexation with metallic ions, altering their availability, speciation and transport properties [3] [4] [5].