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Each year the
U.S. pulp and paper industry generates approximately 3.6 million
dry metric tons of sludge, a waste byproduct. This sludge is disposed
of either by burning or land application. With many states preventing
organic matter being dumped in landfills and clean air ordinances
preventing burning, a disposal method or use for paper sludge is
needed. A solution to sludge disposal will improve the economic
viability of paper production, particularly in the Pacific Northwest,
since numerous paper mills are located in this region.
Wholesale production
of landscape trees and shrubs in the Pacific Northwest was worth
$523.7 million in 1995. Softwood bark is an important component
of container mixes used for plant production in the region, but
this material is becoming harder to obtain and is rising in price
due to reduced logging in the Northwest and increased competition
from other users (landscapers and homeowners). As bark becomes more
difficult to find and more expensive, container producers must find
alternative media components. Likewise, peat moss is an important
component of potting media, but it is often expensive and must be
mined from peat bogs. A University of Idaho scientist has attempted
to solve the sludge waste and potting mix expense problems by conducting
research with paper sludge as a component of potting mixes used
to produce trees and shrubs.
Experiments
conducted during the last several years have demonstrated that many
species of shrubs and trees can be grown in media that contain paper
sludge. In fact, all of the tested plants can be grown in potting
mixes that contain 40 or 60 percent paper sludge, and many tested
species grew well when 80 to 90 percent of the mix contained sludge.
Using paper sludge to replace some or most bark, peat moss, or both
can reduce production costs for container growers since they can
get the sludge for free or may even be paid to take this waste.
Based on data from UI experiments, at least one nursery in the region
is starting to use paper sludge in their potting mixes. Using paper
sludge for landscape plant production is more environmentally sound
than is dumping or burning paper sludge or mining peat bogs, contributing
to sustainability of tree and shrub production.
For more information
contact: Robert
R. Tripepi
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