Effectiveness of electrocoagulation in the removal of arsenic in the effluents of the Loulo mine in Kéniéba (Republic of Mali)

Abstract

Industrial mining activities generate huge amounts of process water that typically has
a variety of hazardous contaminants including arsenic. The method used is the water treatment process based on the electrochemical dissolution of a sacrificial metal
which, once in the effluent and through other related reactions such as water
electrolysis, gives metal hydroxide complexes that will ensure the adsorption and
flocculation of the particles and dissolved polluting compounds. The objective of this
study is to evaluate the effectiveness of the electrocoagulation process in the
elimination of arsenic in the wastewater of Loulo. The arsenic content in wastewater
at baseline was 16.4 mg/L, a value well above the Malian standard for waste water
(0.5 mg/L). At the end of the experiment, which lasted 30 minutes of electrolysis with
an intensity of 1.50 ampere, the arsenic removal rate was 99.82% and the arsenic
content increased to 0.02 mg/L. The operating parameters showed that
electrocoagulation is more suitable for use technologically because of its low
operational cost because it does not require the use of chemicals in the removal of
arsenic in industrial effluents.