Under specific circumstances, mercury concentrations in regions affected by artisanal and small-scale gold mining (ASGM) —mainly in Africa, Asia and South America — can reach 8.0 ug/L in surface water, with extremes up to 100 ug/L. In many cases, these polluted waters are the only available source in those regions to produce drinking water.<br/> <br/>Previous studies have shown that there are limitations in removing high mercury concentrations from surface water through coagulation-sedimentation-filtration (CSF) processes, which is the most common technique used to produce drinking water in communities affected by ASGM.  Additionally, this water treatment may not be efficient enough to provide safe water. The World Health Organization (WHO) guideline for drinking water is 1.0 μg/L.<br/> <br/> Some researchers have postulated that the Hg/NOM ratio limits the efficiency of the coagulation process because the low amount of sulfur reduced sites (Sred) that can effectively bind Hg will not be sufficient if the ratio Hg/NOM is high (&gt;10 μg of Hg/mg of NOM). Since alum is the typical coagulant used in most water plants, in this work it was determined the extent of removal of inorganic mercury at various Hg/NOM ratios via coagulation tests and characterizing adsorption onto alum flocs as a function of pH. Specifically, traditional jar tests were used to evaluate the removal of Hg(II) and NOM via sorption and sorption and precipitation.

Binding of inorganic mercury in surface water to DOM and alum flocs: How much removal can we get?

249th National Meeting (2015)

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