The United States accumulates more solid waste per person per day than any other nation. Efforts to improve landfills and incinerators have not sufficiently alleviated the nation's unmatched waste production . Concerns over the irreversible exhaustion of natural resources, global warming, and pollution have contributed to environmentalists' shifting strategies for minimizing the impact of widespread producer-consumerism. Design for Environment (DfE), an increasingly utilized concept, encourages the systematic integration of environmental considerations into industrial design and production processes . Despite studies exposing Americans' increased loyalty to companies known for their environmental awareness, 17 states have yet to pass a single law requiring manufacturers to invest in the sustainability and waste management of their products . Distributing the responsibility for a product's impact among manufacturers, retailers, and consumers will lessen reliance on end-of-life processes that contribute to pollution and will minimize resource consumption.
Product Stewardship and Extended Producer Responsibility
Product stewardship is a policy in which manufacturers, retailers, and consumers are all considered accountable for counteracting any environmental hazards resulting from product use and disposal . The entire life cycle of a product, from raw mineral extraction to product retirement, must be considered. Extended producer responsibility (EPR) refers specifically to the shift in accountability for the disposal of a product from the government to the producer. Changes in product design and anticipation of environmental detriments allow manufacturers to internalize the end-of-life management costs into the product itself rather than blindly contribute to costly, unsustainable outputs . The California Product Stewardship Act, AB 283, is intended to incentivize manufacturers to design less toxic, more durable, recyclable, and biodegradable products .
The Landfill Problem
Carbon dioxide, methane, nitrogen oxides, ozone, and other gases contribute to global warming by trapping infrared radiation from the sun in the earth's atmosphere . Solar radiation and released infrared radiation from the earth determine global temperatures. Mass product manufacture and disposal contribute enormously to the emission of such greenhouse gases. Soil gas emission surveys in Tuscany, Italy showed that 2,100 tons of methane (CH4) gas and 8,800 tons of carbon dioxide (CO2) gas are emitted into the air each year from the Legoli landfill despite the installation of collecting systems . Both producer and consumer behavior are closely correlated to the amount of material appearing in landfills. Consumers are capable of purchasing more durable goods and are responsible for determining the point at which a product is deemed ready for disposal . Factors including product packaging and composition, on the other hand, are generally controlled at the producer end.
Environmental Innovation in Product Design
Certain product attributes, such as recyclability and energy consumption, result from material choice, product design, and configuration. In other words, the environmental impact in the use and end-of-life phases of a product's life cycle are extremely dependent on the initial design. The concept of pre-emptive life cycle assessment (LCA) was first proposed in the 1970s and has given rise to a myriad of approaches, most of which analyze and evaluate raw materials and components, product function and use, toxicity, and efficiency . The Cumulative Energy Demand (CED) method, most often used to compare the energy intensity of processes, focuses on hazards resulting from energy consumption associated with the production, use, and disposal of a specific item . The Material Input Per Service Unit (MIPS) approach identifies resource consumption, including abiotic materials, air, water, biotic materials, and soil movement, as a direct indicator of a product's potential effect on the environment. Eco Indicator, one of the most widely used models for LCA, takes the entire life cycle inventory into account. A product's potential damage to resources, the ecosystem, and human health are estimated and, ideally, minimized.
Life cycle inventory data is necessary for assessing the environmental impact of a product . While life cycle assessment systems include detailed steps and methods pinpointing environmental hazards, data is often drawn from different sources and varies significantly. This makes it extremely challenging to incorporate findings into product development. However, thoughtless production is an egregious transgression in the face of rising environmental concerns, and manufacturers should strive to carry out such assessments. The following sections outline methods for product stewardship that producers should utilize and consumers should demand from manufacturers.
Design for Disassembly and Supportability
Designing products for easy disassembly is an effective way of avoiding waste and lessening the quantities of material that end up in landfills. Since contaminated materials complicate the recycling process, adding unneeded disposal costs, manufacturers should utilize water-soluble adhesives, avoid secondary coatings or finishes, and stop using composite materials . Standardization of components is an effective method for simplifying supply chains and raising the probability that a product will be recovered and reused.
Methods for Minimizing Energy Consumption
Mass consumption has caused a 300% increase in energy usage in just the last 50 years, but energy consumption is often left out of the discussion on "green" manufacturing. Nevertheless, energy costs continue to grow, nonrenewable sources of energy are used more often than not, and each kilowatt-hour of energy produced causes the emission of two pounds of carbon dioxide gas into the atmosphere.
Energy consumption can be lessened with a methodical approach to determining the most dually efficient state of the devices involved in production . Machines require energy to warm up, produce a part, remain idle, and shut off. Manufacturers often prefer leaving machines idle in order to decrease job-processing time, but this increases the emission of harmful gases. A study carried out at an aircraft small-parts supplier in Wichita, KS showed that 13% of the company's energy consumption could be saved if machines were turned off when not processing jobs . When machines remain idle for long periods of time, the energy required to turn the machine on and off is generally much less than the energy consumed in the sustained idle state .
Manufacturers also make decisions that influence the rate of energy consumption in the use phase. A major aspect of DfE is anticipating and avoiding environmentally erroneous behavior by the consumer . An EcoDesign Strategy Wheel created in the Netherlands suggests reduction of the consumer's need for energy, water, detergent, and other auxiliary materials as a way of decreasing the environmental impact of a product . Energetically expensive equipment and appliances contribute significantly to greenhouse gas emissions.
A product's environmental impact is a result of more than just its functional design. Packaging materials are a significant component of the solid waste produced in the United States . Use of biodegradable plastics instead of conventional plastics in manufacturing is hindered greatly by the heightened expense, approximately 2 or 3 times the alternative cost.
Non-biodegradable, oil-based polymers such as polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyvinyl chloride (PVC) are often used in packaging applications. As mentioned above, processing additives such as fillers, colourants, and plasticizers make recycling of such materials expensive . Consequently, most of these complex materials end up in landfills. In the UK, 18% of all packaging waste comes from plastics, and recycling rates for plastics remain low throughout the world.
Many biodegradable polymers (BDPs) hold the same mechanical properties as other, non-biodegradable materials. Biodegradable plastics, for example, are polymeric materials that can decompose into carbon dioxide, methane, water, inorganic compounds, or biomass . Bio-based BDPs are produced from natural polysaccharides, proteins, and lipids while petrochemical-based BDPs are synthesized from monomers extracted from petrochemical refining. The biodegradable polymers used in the commercial sphere are almost always a combination of bio-based and petrochemical-based molecules in order to maximize cost efficiency and performance .
Microorganisms are capable of converting the majority of plant material back into photosynthetic reactants, carbon dioxide and water. Ideally, BDPs, which are made from agriculturally renewable resources, would follow this natural cycle. Composting and incineration are competing recycling strategies for fossil resources, both of which transform biodegradable materials into carbon dioxide and water. Composting is defined as the accelerated degradation of heterogeneous organic matter by microbes in an aerobic environment . Product compost can be used in agriculture while incineration of BDPs can be used to recover energy .
One difficulty with composting biodegradable plastics is the need for separation from conventional plastics. A study assessing German composting facilities found that sieving magnetic separation, manual sorting, and air classification were common techniques for purifying bio waste. While the facilities evaluated showed great effort, differentiation between biodegradable and non-biodegradable plastics proved difficult and impractical. Proper degradation of BDPs in a composting facility is possible only if BDPs are collected separately in large amounts.
According to global trends, the plastics industry will continue to thrive as increased quantities of the material are used in manufacturing worldwide. Production involving plastics requires energy and raw materials, contributing to emissions and waste, like many other materials . The plastics debate, like environmentalism in general, involves determining whether the associated environmental cost is sufficiently matched with the economic, societal, and perhaps environmental benefits gained through plastic use. As use of plastics in consumer applications has increased, however, the municipal solid waste problem has come to the forefront of the debate.
The producer-consumer nature of the modern developed world has contributed to harmful waste accumulation, exhaustion of natural resources, and global warming. Product stewardship and extended producer responsibility are anticipatory methods for preventing continued, excessive damage to the environment. Despite increased adoption of environmentally benign manufacturing techniques, practices that increase energy consumption, complicate the recycling process, and raise products' ecological footprint are still significant in the industrial sphere. California leads the United States with six product categories covered by EPR laws. Such regulations provide oversight that holds manufacturers accountable for the products they put on the market.
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