Environmental Engineering Reference
In-Depth Information
produce cellulose that then is transformed into paper, burning of biomass to generate energy
reduces the carbon intensity of this material (Allwood et al., 2010).
Besides GHGs, production of packaging materials generates the emission of many pollut-
ants that are released to the atmosphere during the process:
Transformation of wood into cellulose pulp via kraft pulping releases sulfur compounds
(hydrogen sulfide, methyl mercaptan, dimethyl sulfide, and dimethyl disulfide) at a rate of
0.3 to 3 kg per tonne of air dried pulp (10 percent water content), which creates more of a
nuisance problem than a health hazard (World Bank, 1999; Blanco et al., 2004). Emissions
of sulfur dioxide and nitrogen oxides vary widely. Blanco et al. (2004) reported a rate of
0.45 kg/tonne of sulfur dioxide, and 1.12 kg/tonne of nitrogen oxides, whereas the World
Bank (1999) reports 0.5-30 kg/tonne of sulfur dioxide, 1-3 kg/tonne of nitrogen oxides,
and 15 kg/tonne of volatile organic carbon.
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Air emissions from glass manufacturing include nitrogen oxides, sulfur dioxide, particu-
lates, cadmium, arsenic, other heavy metals, fluoride, and hydrogen chloride (World Bank,
1999).
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In the course of aluminum production from ore, the main air emissions from extraction of
alumina include dust from bauxite, limestone, alumina, red mud stacks, sodium salts, and
caustic aerosols from cooling towers. Emission of sulfur dioxide and nitrogen oxides is
produced by boilers, calciners, mobile equipment, and kilns. During the smelting process,
air emissions consist of alumina dust, coke dust, gaseous and particulate fluorides, sulfur
and carbon dioxides, polynuclear aromatic hydrocarbons, carbon tetrafluoride, and carbon
hexafluoride. Emissions from secondary aluminum production (recycling) include
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Picture 12.2
Melted aluminum during the recycling process.
Courtesy Environmental Protection Agency.
