Chemical Precipitation
http://en.wikipedia.org/wiki/Groundwater_remediation
http://www.cleanh2o.com/ww/chemppt.html
Chemical precipitation is commonly used in wastewater treatment to remove hardness and heavy
metals. In general, the
process involves addition of agent to an aqueous waste stream in a stirred
reaction vessel, either batchwise or with steady flow. Most metals can be
converted to insoluble compounds by chemical reactions between the agent and
the dissolved metal ions. The insoluble compounds (precipitates) are removed by
settling and/or filtering.
Chemical precipitation
is a method of wastewater treatment. Wastewater treatment chemicals are added
to form particles which settle and remove contaminants. The treated water is
then decanted and appropriately disposed of or reused. The resultant sludge can
be dewatered to reduce volume and must be appropriately disposed of. Chemical
precipitation can be used to remove metals, fats, oils and greases (FOG),
suspended solids and some organics. It can also to be used to remove phosphorus,
fluoride, ferrocyanide and other inorganics.