The invention allows for {HEAD ~ the repeated treatment} of {TAIL ~ a gas stream} to reduce the level of mercury and other pollutants through reduction steps, allowing targeted treatment of specific compounds 
of
The invention allows for { HEAD ~ the repeated treatment } of { TAIL ~ a gas stream } to reduce the level of mercury and other pollutants through reduction steps , allowing targeted treatment of specific compounds
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH