Treatment Methods for Mercury Removal From Soil and Wastewater

Mercury (Hg) contamination in soil and wastewater has frequently been reported, however, variable concentration was present in soil (0.003–4.6 mg/kg), and in sewage sludge (0.3–7.7 mg/L). To protect the environment and general welfare, it is imperative to address the treatment of Hg in wastewater and soil. In this analysis, we have examined a range of physical, chemical, and biological methods that have proven effective in the removal of Hg from soil and wastewater. These methods include adsorption (≤99%), membrane separation (≤99%) nano-remediation (≤99%), phytoremediation (≤96%) and bioremediation (≤96%) in water or wastewater, whereas soil washing (≤80%), chemical stabilization (≤90%), chemical extraction (≤80%), nano-remediation (≤99%), phytoremediation (≤96%), and bioremediation (≤100%) are the prominent methods for the treatment of Hg in soil. Based on these results, we conclude that biological methods are slow but the most efficient for treatment of Hg contaminated soil and wastewater. Biological methods (phytoremediation and bioremediation) remove Hg from soil and wastewater through reduction, accumulation, and volatilization mechanisms. The combination of one or two methods can be more effective compared to one method. However, further research is required in this direction to affirm practical mass application of these techniques for treatment of Hg contaminated soil and wastewater.