Kevin O'Donnell10.03.08
Expanded Polystyrene (EPS); the plastic we love to hate. It's been around for so long it's hard to imagine what life would be like without it. Let's face it, as plastics go, EPS is very conspicuous - large white pieces limitless in shape and size, not to mention the loose fill "peanuts" that seem to migrate everywhere. It's obnoxiously voluminous. At the same time it troubles us to know that the containers we use to ship our temperature-sensitive healthcare products (as well as use to protect many of the consumer goods we purchase - everything from televisions to double lattes), is ultimately destined to lie in a landfill somewhere for centuries to come. It's another inconvenient truth of 21st century life; one of those things we know we should do without but which we will never be prepared to relinquish. But in many respects, EPS has been unfairly vilified.
While wringing our hands over the economic, health and environmental concerns, including its consumption of fossil resources, pollution, energy to manufacture and accumulation of wasted plastic in the environment, it's easy to overlook the advantages and benefits of EPS and the comparatively low impact it has in this regard to other packaging materials.
Love it or hate it, EPS is pretty remarkable stuff. It's extremely versatile and durable. The structure of EPS bead is 98% air and its initial thermal properties are maintained throughout its entire working life. It can be molded, cut and tinted into virtually any shape, size or color; it's inert, non-toxic, moisture resistant, and rot proof. It is also totally absent of any nutritional value so no fungi or micro-organisms can grow within EPS. Pound for pound it offers greater advantages at less cost than any other packaging material. And the energy to manufacture it is less than that of paper, with fewer negative impacts to the environment overall than just about any other packaging material. Because of its light weight, transporting it reduces fuel consumption.
One of the more remarkable attributes of EPS is that it can be engineered for optimal performance depending on its application. The mechanical properties of EPS foam depend primarily on the material density. Generally, strength and insulation properties increase with density. This unique characteristic allows a packaging engineer to fine-tune performance by implementing simple processing changes without the need to redesign or retool. EPS has excellent thermal insulation properties. Depending on its density, its thermal conductivity (k factor) is about 0.24 per inch (BTU-In./Ft.2Hr F). For shock cushioning, the EPS packaging industry has developed typical cushioning curves for applications in transport packaging which are not significantly affected by changes in temperature. Dimensional stability is another important characteristic of EPS foam; it will retain its original shape and size under widely varying environmental conditions. Optimizing these requirements can help to minimize raw material content.
The production of EPS utilizes the by-products of the petroleum and natural gas industries. A small fraction of 1% of all petroleum and natural gas consumed in the U.S. is used for all of the EPS packaging products made in America, according to the Alliance of Foam Packaging Recyclers. The blowing agent in EPS is pentane gas, which is dissolved into the base material and is released during the conversion of the raw material to a finished piece. This has a minimal global warming potential making only a slight contribution to the greenhouse effect. Atmospheric emissions from the production of polystyrene are one-half to one-third of those made from paper production.1 The main environmental effects are substances released into the atmosphere, particularly when raw EPS is made and when transporting finished goods to users. There are no chlorofluorocarbons (CFCs) or hydrochlorofluorocarbons (HCFCs), gasses widely attributed to the depletion of the ozone layer, used in the manufacture of EPS.
During the processing (molding) cycle, pentane is released into the atmosphere and water and steam used in its manufacture, are produced as by-products. Wastewater volume from polystyrene production is 1/3 less than that resulting from producing a comparable amount of paper.1 But compare this to the corrugate box the foam container or finished piece comes with - or any other paper products in the packaging system - and you will see that considerably more environmental impact is contributed by processing the corrugated paper components. The paper material used in its manufacture, despite its recycled content, is responsible for 94% of the total water eutrophication, or water pollution, due to nitrates and phosphates, 74% of the waste production by volume, 52% of the water consumption and 47% of the primary energy consumption than that of the EPS in the packaging system.2
The issue of EPS and its relationship to the solid waste crisis is one in which the facts are not fully understood. The concerns center around the issue of degradability. It is true that EPS does not degrade in landfills. Many people assume that because EPS does not degrade it must be a major problem in landfills. Nothing, not paper, plastic, food or any other "degradable" materials breaks down in a landfill - and it's not supposed to. Modern landfills are specifically designed to reduce the air, water and sunlight needed for biodegradation in order to prevent the generation of volatile methane gas and leachate (liquid run-off) which could contaminate ground water. In essence, materials 'mummify' in the oxygen-deprived or anaerobic environment of modern landfills.
Studies conducted by the University of Arizona's Garbage Project state that packaging does not contribute unduly to the solid waste problem. Researches found that paper waste is the largest single component in landfills: 50% by volume compared to 10% for plastics. EPS actually has some advantages to landfill management. Since it is inert and non-toxic the landfill site becomes more stable. EPS aerates the soil, encouraging plant growth on reclaimed sites. Since it does not degrade it will not leach any substances into the groundwater nor will it form explosive methane gas. Still, since nearly all EPS eventually ends up in a land fill, this is not a preferred option.
Prior to 1988, there was essentially no recovery of post-consumer EPS for recycling. Although the availability of polystyrene recycling programs varies by community, in 2006 more than 57 million pounds of polystyrene was recycled.3 This includes 27 million pounds of post-commercial packaging; five million pounds of post-consumer packaging and 26.6 million pounds of post-industrial recovery. Post-consumer and post-commercial recycling are defined as any material that is recycled after its intended use - while post-industrial recovery includes EPS facility scrap that is recycled but never served its intended end-use as a packaging material. This represents a 19.3% recycling rate compared to 9.5% in 1998.4 The rate is higher in Europe; 25% in 2002 and 35% in 2006.2
Curbside collection of EPS (and other plastics) within communities is often a well-intentioned environmental gamble and economic catastrophe. It requires far greater energy to recycle plastic polymers compared to other materials such as glass and aluminum, and processing used plastics often costs more than virgin plastic. It's easy to get "upside down" on energy consumption when it comes to recycling and it can do more to promote global climate change than reduce it. The success of any recycling program is highly dependent on geographic proximity, tipping fees (dumping fees), the capricious price of oil and petroleum products, and other operational costs which do little to achieve recycling goals and have little affect on reducing environmental impacts.
But as good stewards of the environment we have a responsibility to bite the bullet on these concerns. Recycling a pound of plastic requires about 1,000 BTUs of energy compared to 11,500 BTUs required for recycling the same amount of paper.1
Generally, the most direct re-use of EPS is grinding it up and adding it to virgin material during production. This is commonly referred to as regrind content. It is acceptable to put as much as 10% regrind material into insulated containers for example, with no impact on the containers mechanical attributes or insulating capabilities. Most biopharmaceutical companies specify no regrind, or 100% virgin material in their containers, even though it is in non-product contact and used as tertiary packaging. This is unnecessary and wasteful.
Alternatively, EPS can be melted and extruded to make compact polystyrene for items such as plant pots, coat hangers, and as a wood substitute. As part of mixed plastic waste it can be recycled to make durable goods such as park benches, fence posts and road signs, ensuring the material has a long and useful second life.
There are new densification systems on the market that can reduce the volume of EPS by 95%, creating small blocks of material that are sterile and easy to handle and can be sold and reused in new products or as fuel. Transporting waste polystyrene in this form is much more energy efficient.
There is energy to be recovered from post-consumer EPS in the form of heat from incineration. The caloric value of EPS available for heat recovery is slightly more than that of coal by weight. In a modern incinerator, EPS releases most of its energy as heat, aiding in the burning of municipal solid waste and emitting only carbon-dioxide, water vapor and a trace of non-toxic ash. The fumes are non-toxic and are not harmful to the environment as no dioxins or furans are emitted. The energy gained can be used for local heating and the generation of electricity.
There is one new application for EPS that is so revolutionary, it is likely to change the way we think about plastics: a sustainable recycling program that is estimated to produce a ratio of almost 300:1 in CO2 emission reductions per pound of recycled EPS, which is the equivalent of taking 2.5 cars off the road for a full year. More on that in next month's Advanced Degrees column in Contract Pharma.
References
Facts About Plastic Loose Fill, Alliance of Foam Packaging Recyclers. Crofton, Maryland 2004.
Life Cycle Assessment of Expanded Polystyrene Packaging Case Study, May, 2002. European Union Manufacturers of Expanded Polystyrene (EUMEPS), Brussels, Belgium.
2006 National Post-consumer EPS Recycling Rate Report, Diagnostics Plus, September 2007.
2006 EPS Recycling Rate Report, Alliance of Foam Packaging Recyclers
While wringing our hands over the economic, health and environmental concerns, including its consumption of fossil resources, pollution, energy to manufacture and accumulation of wasted plastic in the environment, it's easy to overlook the advantages and benefits of EPS and the comparatively low impact it has in this regard to other packaging materials.
EPS: The 'Baking Soda' of Plastic
Love it or hate it, EPS is pretty remarkable stuff. It's extremely versatile and durable. The structure of EPS bead is 98% air and its initial thermal properties are maintained throughout its entire working life. It can be molded, cut and tinted into virtually any shape, size or color; it's inert, non-toxic, moisture resistant, and rot proof. It is also totally absent of any nutritional value so no fungi or micro-organisms can grow within EPS. Pound for pound it offers greater advantages at less cost than any other packaging material. And the energy to manufacture it is less than that of paper, with fewer negative impacts to the environment overall than just about any other packaging material. Because of its light weight, transporting it reduces fuel consumption.
One of the more remarkable attributes of EPS is that it can be engineered for optimal performance depending on its application. The mechanical properties of EPS foam depend primarily on the material density. Generally, strength and insulation properties increase with density. This unique characteristic allows a packaging engineer to fine-tune performance by implementing simple processing changes without the need to redesign or retool. EPS has excellent thermal insulation properties. Depending on its density, its thermal conductivity (k factor) is about 0.24 per inch (BTU-In./Ft.2Hr F). For shock cushioning, the EPS packaging industry has developed typical cushioning curves for applications in transport packaging which are not significantly affected by changes in temperature. Dimensional stability is another important characteristic of EPS foam; it will retain its original shape and size under widely varying environmental conditions. Optimizing these requirements can help to minimize raw material content.
Energy Cost and Environmental Impacts To Produce Virgin EPS
The production of EPS utilizes the by-products of the petroleum and natural gas industries. A small fraction of 1% of all petroleum and natural gas consumed in the U.S. is used for all of the EPS packaging products made in America, according to the Alliance of Foam Packaging Recyclers. The blowing agent in EPS is pentane gas, which is dissolved into the base material and is released during the conversion of the raw material to a finished piece. This has a minimal global warming potential making only a slight contribution to the greenhouse effect. Atmospheric emissions from the production of polystyrene are one-half to one-third of those made from paper production.1 The main environmental effects are substances released into the atmosphere, particularly when raw EPS is made and when transporting finished goods to users. There are no chlorofluorocarbons (CFCs) or hydrochlorofluorocarbons (HCFCs), gasses widely attributed to the depletion of the ozone layer, used in the manufacture of EPS.
During the processing (molding) cycle, pentane is released into the atmosphere and water and steam used in its manufacture, are produced as by-products. Wastewater volume from polystyrene production is 1/3 less than that resulting from producing a comparable amount of paper.1 But compare this to the corrugate box the foam container or finished piece comes with - or any other paper products in the packaging system - and you will see that considerably more environmental impact is contributed by processing the corrugated paper components. The paper material used in its manufacture, despite its recycled content, is responsible for 94% of the total water eutrophication, or water pollution, due to nitrates and phosphates, 74% of the waste production by volume, 52% of the water consumption and 47% of the primary energy consumption than that of the EPS in the packaging system.2
Degradability
The issue of EPS and its relationship to the solid waste crisis is one in which the facts are not fully understood. The concerns center around the issue of degradability. It is true that EPS does not degrade in landfills. Many people assume that because EPS does not degrade it must be a major problem in landfills. Nothing, not paper, plastic, food or any other "degradable" materials breaks down in a landfill - and it's not supposed to. Modern landfills are specifically designed to reduce the air, water and sunlight needed for biodegradation in order to prevent the generation of volatile methane gas and leachate (liquid run-off) which could contaminate ground water. In essence, materials 'mummify' in the oxygen-deprived or anaerobic environment of modern landfills.
Studies conducted by the University of Arizona's Garbage Project state that packaging does not contribute unduly to the solid waste problem. Researches found that paper waste is the largest single component in landfills: 50% by volume compared to 10% for plastics. EPS actually has some advantages to landfill management. Since it is inert and non-toxic the landfill site becomes more stable. EPS aerates the soil, encouraging plant growth on reclaimed sites. Since it does not degrade it will not leach any substances into the groundwater nor will it form explosive methane gas. Still, since nearly all EPS eventually ends up in a land fill, this is not a preferred option.
Recyclability
Prior to 1988, there was essentially no recovery of post-consumer EPS for recycling. Although the availability of polystyrene recycling programs varies by community, in 2006 more than 57 million pounds of polystyrene was recycled.3 This includes 27 million pounds of post-commercial packaging; five million pounds of post-consumer packaging and 26.6 million pounds of post-industrial recovery. Post-consumer and post-commercial recycling are defined as any material that is recycled after its intended use - while post-industrial recovery includes EPS facility scrap that is recycled but never served its intended end-use as a packaging material. This represents a 19.3% recycling rate compared to 9.5% in 1998.4 The rate is higher in Europe; 25% in 2002 and 35% in 2006.2
Curbside collection of EPS (and other plastics) within communities is often a well-intentioned environmental gamble and economic catastrophe. It requires far greater energy to recycle plastic polymers compared to other materials such as glass and aluminum, and processing used plastics often costs more than virgin plastic. It's easy to get "upside down" on energy consumption when it comes to recycling and it can do more to promote global climate change than reduce it. The success of any recycling program is highly dependent on geographic proximity, tipping fees (dumping fees), the capricious price of oil and petroleum products, and other operational costs which do little to achieve recycling goals and have little affect on reducing environmental impacts.
But as good stewards of the environment we have a responsibility to bite the bullet on these concerns. Recycling a pound of plastic requires about 1,000 BTUs of energy compared to 11,500 BTUs required for recycling the same amount of paper.1
Generally, the most direct re-use of EPS is grinding it up and adding it to virgin material during production. This is commonly referred to as regrind content. It is acceptable to put as much as 10% regrind material into insulated containers for example, with no impact on the containers mechanical attributes or insulating capabilities. Most biopharmaceutical companies specify no regrind, or 100% virgin material in their containers, even though it is in non-product contact and used as tertiary packaging. This is unnecessary and wasteful.
Alternatively, EPS can be melted and extruded to make compact polystyrene for items such as plant pots, coat hangers, and as a wood substitute. As part of mixed plastic waste it can be recycled to make durable goods such as park benches, fence posts and road signs, ensuring the material has a long and useful second life.
There are new densification systems on the market that can reduce the volume of EPS by 95%, creating small blocks of material that are sterile and easy to handle and can be sold and reused in new products or as fuel. Transporting waste polystyrene in this form is much more energy efficient.
Energy Recovery
There is energy to be recovered from post-consumer EPS in the form of heat from incineration. The caloric value of EPS available for heat recovery is slightly more than that of coal by weight. In a modern incinerator, EPS releases most of its energy as heat, aiding in the burning of municipal solid waste and emitting only carbon-dioxide, water vapor and a trace of non-toxic ash. The fumes are non-toxic and are not harmful to the environment as no dioxins or furans are emitted. The energy gained can be used for local heating and the generation of electricity.
New sustainable Life for EPS
There is one new application for EPS that is so revolutionary, it is likely to change the way we think about plastics: a sustainable recycling program that is estimated to produce a ratio of almost 300:1 in CO2 emission reductions per pound of recycled EPS, which is the equivalent of taking 2.5 cars off the road for a full year. More on that in next month's Advanced Degrees column in Contract Pharma.
References