Environmental Engineering Reference
In-Depth Information
Use of reusable packages
The use of reusable secondary and tertiary packaging is a widespread practice by the food and
beverages processors and distributors. Plastic milk crates, internal bulk shippers, poultry and
meat trays, pallets, and bakery trays are extensively used in closed-loop systems (Brody,
2010a; Demetrakakes, 2010). The use of returnable primary containers was common before
one-time use containers become available and created the practice of disposable packaging.
Disposable packaging has several advantages including safety, simplified distribution,
elimination of transportation of returning containers, elimination of the cleaning step, and in
the case of plastic containers, a significant reduction of weight in comparison to their glass
counterparts. From the consumer viewpoint, disposable packaging is highly convenient: open
it, use the contents, and toss it! Unfortunately, disposable packaging is the antithesis of the
cradle-to-cradle cycle and likely unsustainable in the long run.
A life cycle assessment of returnable and disposable beer bottles in Portugal indicated that
returnable bottles could be cycled up to 6 times and that by the second cycle the environmen-
tal impact was lower than disposable bottles (Mata and Costa, 2001). In Canada, many
breweries use returnable bottles and cycles them up to 15 times before they are melted to make
new bottles (Johnson, 2008). This reusing practice—in the Canadian example—indicates the
economic feasibility; the environmental impact, however, could be judged only by conducting
a life cycle assessment.
Wooden pallets are reusable, or they can be recycled into other products but often they are
disposed of in landfills. In the United States, it is estimated that 2 to 3 percent of the landfill
waste comes from disposed pallets (Buehlmann et al., 2009). A life cycle assessment of pallets
in Spain concluded than reuse is a better option than recycling in terms of energy consumption
and other environmental indicators (Gasol et al., 2008).
Returnable packaging cannot be used for all food packaging applications because it is
limited to a number of specific uses. In addition, it is not the absolute answer to the long-term
packaging sustainability. However, it is currently the closest approach to a cradle-to-cradle
cycle.
Biobased polymers for packaging
There are three categories of biobased polymers with potential use in food packaging:
1. Polymers directly extracted from biomass, such as polysaccharides and proteins.
2. Polymers produced by chemical synthesis using biobased monomers (e.g., polylactic
acid).
3. Polymers produced by microorganisms or genetically modified bacteria (e.g., polyhy-
droxyalkonoates) (Weber, 2000).
Polylactic acid, or PLA, however, is the only price-competitive biobased polymer at the
moment capable of emulating some of the properties of petroleum-based polymers, with com-
petitive prices, and that can be processed using standard equipment. PLA can be thermo-
formed, injection molded, extruded into films, and laminated. PLA is also biodegradable and
compostable, which with the current solid waste management system has not too much value
for the following reasons:
If PLA-based packaging is recycled then it falls under the recycling code #7 (Others) and
becomes mixed with petroleum-based polymers.
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