Treatment of arsenic contaminated groundwater using Arachis hypogaea

Abstract

Arsenic has a detrimental effect on both the environment and humans. In many parts of the world, arsenic has been detected in drinking water sources above acceptable levels. Considering the fact that millions of people are at high risk of arsenic poisoning via water intake, arsenic remediation from drinking water has become a global issue of serious concern. Chemical coagulants are already being used for treatment but their enormous cost, human and environmental issues associated with their use have led to searching for alternatives like natural coagulants (plant-based). In this study, laboratory scale studies using jar test experiments were performed on synthetic arsenite contaminated groundwater to analyse the efficiency of Arachis hypogaea (groundnut seed) on the treatment of arsenic contaminated water. Experiments were carried out using synthetic arsenite contaminated borehole water with pH kept constant at 7.30. Results indicated that groundnut seed extract was able to significantly reduced arsenite in water either as primary coagulant or as coagulant aid (using alum as primary coagulant). As primary coagulant, above 90% arsenite reduction was achieved and as a coagulant aid about 99.97% arsenite reduction was achieved. The pH of the treated water was within neutral (basic) due to the buffering capacity of the seed extract. Therefore, results from this study revealed that groundnut seed has potential for use as primary coagulant or as coagulant aid (with alum as primary coagulant) for the treatment of arsenic contaminated groundwater.