... an 80-foot tall Glass Former Silo was installed at the Waste Treatment Plant on March 24, 2008, again changing the skyline of the construction site. The silo, which will store and dispense silica during vitrification (glass-making) operations, weighs 78,100 pounds and is the tallest of the 13 silos needed at the plant. To-date, six silos have arrived and three have been installed.  Each of the 13 silos will hold a different glass-forming material that will be dispensed to the WTP’s vitrification facilities in the proper combinations for each batch of glass.