Removal of Mercury in the Environment
|Removing mercury from the water can be achieved using four
processes: Coagulation/Filtration, Granular Activated Carbon,
Lime Softening, and Reverse Osmosis.
Coagulation/filtration is a common treatment which uses AlSO4
that reacts with the mercury to form a solid which can precipitate
out of the water. The sludge then must be disposed of in a hazardous
waste landfill. This process is beneficial because it costs
very little and is reliable.
Granular activated carbon uses porous carbon media. This media
is a very heavy charcoal material. As the water passes through,
the dissolved contaminants are absorbed and held on the solid
surface. This process has its limitations because the effectiveness
depends on the concentration of mercury in the water.
Lime Softening uses excess Ca(OH) to raise the pH level and
then the heavy metal precipitates out as Hg(OH). A benefit of
this method is lower costs and proven reliability.
In reverse osmosis, water is pushed through a semi permeable
membrane. A Common membrane material is a polyamide film. This
produces high quality water, but is fairly expensive.