Flue gas from the melter enters a secondary combustion chamber (SCC), where it is subjected to
an additional two (2) seconds residence time at temperature to ensure complete combustion of
any organic compounds. The flue gas exiting the SCC is cooled by direct water injection to a
temperature of about 177° to 204°C (350° to 400°F) to prevent the formation of dioxin and furan
precursors. Powdered lime (CaO) is injected into the flue gas to capture HCl, SO2 and other acid
gases. The flue gas then passes through a bag house to capture the spent lime, fine particulates,
and NaCl and KCl volatilized from the estuarine sediments. From the bag house, the flue gas
passes through a fixed bed of activated carbon to capture volatile metal species. In an alternative
process configuration, powdered activated carbon can be injected into the flue gas stream to
capture volatile metals and be removed by a second bag house. The clean flue gas is vented to
the atmosphere.