Scrap gypsum drywall
is currently added to composting systems in a number of
locations. Many of these systems are located at waste processing
sites that already have compost operations in progress. While the
paper fraction of the drywall can certainly biodegrade as part of the
compost, it
important to note that the gypsum itself will not biodegrade to any
major extent and will instead be incorporated into the final compost
product. This results in a calcium- and sulfur-rich compost,
which
may have a benefit for some crops (as described in the section on land application).
Gypsum
also offers the potential to bind odors associated with
ammonia. On the other hand, if the composting system is not kept
aerobic, anaerobic microorganisms can result in the production of
hydrogen sulfide, a foul smelling gas (see discussion on odors from landfills).
The application of gypsum drywall to mechanically agitated compost
systems (e.g. a windrow
turner) tends to work better than static systems (e.g. a forced air
static pile) because the mixing and breakup of the gypsum that occurs.
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Paper
separated from gypsum drywall to be mixed with yard trash for windrow
composting
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