Arsenic removal from groundwater in Morelia through an oxidation-coagulation-flocculation-filtration process

Abstract

In the modification to NOM-127-SSA1-2021 (SS, 2022), stricter maximum permissible limits were established for human consumption water parameters, such as arsenic, a contaminant that could cause severe health issues and that has been found in some underground water supply sources in the city of Morelia. The present project proposes an oxidation-coagulation flocculation-filtration process for its removal. Parameters such as pH, electrical conductivity, turbidity, color, fluorides, and aluminum, were evaluated. Jar tests were conducted using 6 mg/L of aluminum sulfate and 2 mg/L of polyaluminum chloride as reagents. Three different filters were tested: (i) silica sand, (ii) activated carbon, and (iii) silica sand, zeolite, and activated carbon. The results show that the water treatment with the combined filter (iii) achieves a removal efficiency of up to 90% of arsenic.