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C&D wood debris
can be burned to create electrical energy. Boralex, Inc., a Canadian-owned
company, is the largest producer of electrical energy from wood residues in
all of North America. Boralex owns and operates eight plants, five of which
are located in Maine, creating a total of more than 250MW of power. Of the
three million tons of wood burned at the facilities, about ten percent is
C&D wood debris, burned in two Maine plants and one facility in New York.
(Roy,
2002). Wood waste recovered from demolition sites and excess wood from the
construction process can be used in many other ways.
(See also wood waste)
C&D debris
usually makes a good fill material or aggregate. Instead of using up
expensive, virgin resources for lower-value purposes, C&D waste can be
utilized as a cheaper, yet just as effective, alternative
(Dolan,
1999). The most
common use of crushed concrete is as road-base gravel, but it is often used
as an aggregate in asphalt or concrete. In 1998 it was estimated that up to
50 million tons of asphalt and concrete from torn up roads is reused.
Twenty to fifty percent is reused as Reclaimed Asphalt Pavement
(USEPA,
1998).
Metals are the
most-recycled C&D materials, as there is usually a good market for ferrous
metals. Much of the C&D waste metal recovered is melted down to create new
products from the old metal. According to the Steel Recycling Institute,
85% of all C&D steel is recycled
(USEPA,
1998).
Asphalt shingles
gathered from C&D processes can be used in making hot or cold mix asphalt,
or even new roofing materials. Shingles that are excess in the construction
process are more widely used for recycling than used asphalt shingles
collected from a demolition site
(USEPA,
1998).
The gypsum
material in sheetrock can easily be removed from the paper backing for use
in manufacturing new sheetrock. Gypsum has many other practical uses as
well. (See also Crushed Sheetrock
Gypsum) |
