New York/ New Jersey Harbor: Alternative Methods for Ex ... - CLU-IN

(Westinghouse, 4-3). In order to produce uniform roofing granules, the molten material
is granulated. The molten glass may also be shattered by quenching it with water to form
aggregate.
The offgas produced by the vitrification process is treated through a system of scrubbers,
a demister/separator, and exhauster. The Venturi scrubber first cools the gas stream,
eliminates sulfur oxides, and condenses volatile salts. Condensed particulates are
removed from the stream by the scrubber. The separator/demister then performs two
major tasks: removing additional aerosols and solid particulates and treating exhaust.
The separator/demister scrubs the stream from the exhaust, then traps and sends water
soluble offgas products to a holding tank. The offgas then goes to one of two places.
The majority of the stream is composed of of innocuous offgases such as N2, O2, and CO2
which are allowed to escape into ambient air. The gas, that does not meet the standards
to be released into the atmosphere, is sent back to the scrubber for further processing.
Residuals
Six residuals are produced by the Westinghouse Plasma Vitrification Process. Three of
the six by-products are solid waste, two are clean water, and one is clean offgases. 2200
tons of gypsum (calcium sulfate), 400 tons of oversized material, 90 tons of precipitated
metals (from the scrubber water), 52 million gallons of filtrate and rinse water, 700,000
gallons of scrubber water bleed, and 2.4 billion standard cubic feet of clean offgases are
estimated to be produced from processing 100,000 cubic yards of contaminated sediment
each year.
The three solid waste by-products: gypsum, oversized material, and precipitated metals,
can be disposed of in a non-hazardous landfill. Precipitated metals must first be
encapsulated before they are put in a landfill. Alternatives to disposal in a landfill also
exist for each of the three forms of solid waste. Gypsum can be used, oversized material
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