Remediation of arsenic-contaminated groundwater

The purpose of the project reported herein is to determine effective reactive materials to remove arsenic from groundwater. Five different reactive materials (iron filings, nanoiron, iron-coated sand, iron powder and coconut husk) were tested in arsenic solutions. Two different oxidation states of arsenic [As(III) and As(V)] were tested. The results showed that As(III) is easier to remediate than As(V). Arsenic was removed below detection level with iron filings and nanoiron, while other reactive materials did not reduce the arsenic to the required standard. Coconut husk had no effect on the remediation of arsenic. All the reactants absorbed the arsenic using adsorption. Based on the data, contaminated groundwater may be treated using an ex-situ method such as an above-ground reactor, or an in-situ method such as injecting the nanoiron directly or using iron filings in a permeable reactive barrier.