Studies in Sustainability

June 6, 2013 Previous day Next day

By Deborah Jackman, PhD, PE, LEED AP™ - originally posted on 04/04/2013

plowing-with-oxen-teams.jpg

The Painting and its Historical Significance:

“Plowing with Oxen Teams” was painted in 1866 by the English artist, William Watson. The original painting is oil on canvas and is 32 inches by 44 inches in size. The painting depicts an idyllic bucolic scene. In the foreground, farmers are urging the team of oxen to pull the plow through the fertile soil, assisted by the urgent barking of the farm dog. In the background is a spectacular mountain vista and clear blue sky. The scene evokes nostalgia for a highly idealized view of farming as it was practiced in the past.

In fact, farming in the past was far from glamorous. It involved back-breaking manual labor, working from dawn to dusk, and contending with Nature’s fickleness — frost, drought, hail, high winds, plant disease, insect infestations, and flooding. Beginning in the early 20th century, advances in farming technology – gasoline-powered tractors, chemical pesticides, and commercial fertilizers — revolutionized agriculture. The dominant agricultural production model in developed countries such as the United Stated changed from the small scale, family farm model to the large scale, heavily mechanized agribusiness model. With this change came the promise of greater productivity, higher crop yields, and cheaper food supplies. It also facilitated the migration of many people from a rural lifestyle to an urban one, since fewer individuals were needed to work the land. However, modern agricultural practices are not without some very negative side-effects, and are arguably not sustainable. In response to some of the negative environmental and societal impacts of modern agribusiness, a strong counter movement in sustainable agricultural practices has emerged over the last several decades. The modern sustainable agriculture movement does not advocate a return to purely traditional farming methods of the past, but rather advocates for combining some aspects of modern technology with traditional practices shown to have scientific benefits, to produce a model that is sustainable over the long term.

The political tensions and scientific controversies that exist currently between advocates for the large-scale agribusiness model and the agricultural sustainability model are too complex and broad in scope to be covered in this brief essay. However, to illustrate the issues involved in this broader controversy, this essay will examine one hot-button issue — how genetically modified (GM) crops are impacting agricultural production and affect the sustainability of our farming system.

An Introduction to Genetically Modified (GM) Crops:

Genetically Modified (GM) crops are plants normally used to feed humans or livestock which have been modified using genetic engineering techniques to introduce traits that allow the plant to resist pests, withstand herbicide applications designed to eliminate weeds, and improve growth rates. The genes of the plant are altered in such a way so as to introduce a trait that does not occur naturally in that particular plant species. Genes from a totally different plant species or even from life forms from other biological kingdoms (bacteria and animal species) may be introduced into the genetic material of the subject plant in order to introduce the desired trait.

GM crops differ from crops improved through selective breeding or through naturally induced mutations primarily because of the potential for introduction of inter-kingdom genetic matter. Recalling our basic high school biology, we know that life forms are classified as belonging to one of six kingdoms — the plant kingdom, animal kingdom, fungi kingdom, bacteria kingdom, chromista kingdom (members of which include several types of seaweed and diatoms), and the protozoa kingdom. Horizontal gene transfer is the flow of genes across species. Such flow of genetic material can and does occur naturally. For example, the development of antibiotic resistance in bacteria is the result of horizontal gene transfer between bacteria. When a plant breeder develops a hybrid grain such as triticale (a hybrid of wheat and rye) using conventional plant cross-breeding techniques, horizontal gene transfer is also involved. But, what differs with GM crops is that the gene transfer that is induced can cross kingdom lines and involves gene transfers that would likely never occur spontaneously in nature or even using conventional plant selective breeding techniques. For example, the most famous GM crop in common agricultural use today — Roundup Ready soybeans — contains genetic material from several species of bacteria. The resulting transgenic plant is not susceptible to damage from Roundup, a common herbicide. Therefore, farmers can control weeds by spraying Roundup on these crops, killing naturally occurring weeds, but not harming the genetically altered crop. Crop yields are improved because competition with weeds is eliminated and the farmer saves time and labor because it is quicker to spray a field with Roundup than to perform mechanical cultivation to eliminate the weeds. [1]

Another common GM crop is corn that has had genetic material from the bacteria, Bacillus thuringiensis, introduced into its DNA. Bacillus thuringiensis (Bt) is naturally toxic to caterpillars. By introducing Bt genes into corn, infestations of Corn Earworm, a common insect pest in corn, are eliminated without having to spray the corn with externally applied pesticides that could drift in the wind or run off into streams.

The use of GM crops is widespread. In the US, 86% of corn, 93% of soybeans, 93% of cotton, and 87% of canola is genetically modified to be either Roundup resistant or to resist predation by caterpillars through insertion of the Bt gene [2]. The U.S. accounts for 50% of all GM agricultural production and trade world-wide, with Canada, Australia, Argentina, Brazil, and China also accounting for significant percentages [3]. In other parts of the world, GM crops are much less common, either due to the increased seed costs of such crops, governmental prohibitions or citizen resistance to their use, such as in the European Union. Most genetically modified crop seeds are produced by a small number of large corporations, with Monsanto Corporation the largest supplier of GM seed. Such seed is patented and seeds produced from GM plants cannot be saved to be used for seed for subsequent generations of plantings. GM seed must be purchased new each year from the corporate supplier holding the patent or risk incurring substantial legal and monetary penalties [4].

In addition to their use as agricultural crops, GM plants have been created to synthesize drugs, facilitate their use as bio-fuels, and bio-remediate contaminated soils. Genetically modified carrots are used to produce the drug Taliglucerase alfa, used to treat Gaucher’s Disease [5]. GM bananas have been created which produce a human vaccine against Hepatitis B, although these are not yet in commercial production [6]. The Swiss-based company, Syngenta, has received USDA approval to market corn seed, trade-marked Enogen, which has been genetically modified to convert its starch to sugar more readily in order to speed production of ethanol-based bio-fuels [7].

The Sustainable Agriculture Movement:

Sustainable agriculture is defined as “an integrated system of plant and animal production practices having a site-specific application that will last over the long term. Sustainable agriculture has the following goals:

    1. To satisfy human food and fiber needs
    2. To enhance environmental quality and the natural resource base upon which the agricultural economy depends
    3. To make the most efficient use of non-renewable resources and on-farm resources and integrate, where appropriate, natural biological cycles and controls
    4. To sustain the economic viability of farm operations
    5. To enhance the quality of life for farmers and society as a whole”

[8]

Far from being a fringe movement, the sustainable agriculture movement has been recognized by the U.S. federal government in the 1990 farm bill [9], and by the United Nations in its Agenda 21 document [10]. The sustainable agriculture model is frequently discussed in terms of a triad — economic sustainability, environmental sustainability, and societal sustainability. In fact, Agenda 21 discusses how sustainable agriculture can help promote all three of these elements.

Of the five goals set forth by the sustainable agriculture movement, modern agribusiness in the U.S. is currently very good at achieving the first, i.e., satisfying food and fiber needs, in a very inexpensive fashion. Food costs as a percentage of total family income are lower in the U.S. than in most other countries in the world. However, we achieve this cheap food production by largely ignoring or violating the other four principles. This creates a false economy because it is not sustainable over the long term. While modern agribusiness can bring us food cheaply now, our food prices will inevitably rise and scarcity will ensue once the negative impacts of our current food production model reach their tipping points. Demographers project the global population will exceed 8 billion by the year 2030. Despite claims by agribusiness that its “modern” methods are the only ones that can ensure adequate food for all of the Earth’s projected inhabitants, there are other voices that disagree. Andre Leu, Chair of the Organic Federation of Australia, is on record saying that sustainable farming is the ONLY way to meet world food demand in the future [11].

As noted earlier in this article, we are using the GM crop debate as a microcosm to explore the more general issues surrounding modern agribusiness overall. To this end, in the next section we explore how the use of GM crops is problematic to the sustainable agriculture movement.

Sustainable Agriculture versus Genetically Modified Crops — Attendant Scientific and Political Controversies:

Soil Erosion and Water Scarcity: Proponents of GM crops argue that one of the chief promises of such crops is that they will enable farmers, especially those in developing countries, to grow plants on very marginal lands — including those with little water, depleted soil, or areas prone to frosts. This is because transgenes can be inserted into various crops to reduce that plant’s need for water, nitrogen, and to make it less frost susceptible. While this sounds like a noble goal, and while it may be true over the short term, it will likely lead to long term environmental damage.

To understand why, one must first understand why farmers must use marginal lands in the first place. In much of the world, soil conservation is not being given high enough priority. In Africa alone it is estimated that over a billion tons of soil are eroded every year. Such erosion occurs when forests and other natural windbreaks adjacent to tillable areas are cut down or when excessive or improper tilling methods are used. Wind erosion then occurs as topsoil is literally blown away. The removal of hedgerows and other vegetation buffers in order to maximize tillable acreage also means that the roots from plants that help to anchor soil in place during heavy precipitation events are no longer present to prevent topsoil run-off. The increased use of ammonia based fertilizers, rather than using compost for fertilizing crops reduces soil texture and trace elements needed for maximum plant vigor. This global phenomenon of loss of topsoil quantity and quality is being called “Peak Soil.” It means that we are currently at the “peak” of soil availability and can expect ever decreasing soil fertility if we do not make a concerted effort to improve soil management practices. Similarly, wholesale destruction of tropical rainforests has altered global rainfall patterns and over-pumping of aquifers has created shortages of water available to agriculture. Emphasis needs to be on water conservation practices including aggressive water reuse and recycling, and on soil moisture conservation strategies such as mulching and enhancement of soil texture so as to maximize its ability to hold moisture.

In keeping with the sustainable agricultural goal of enhancing environmental quality and the natural resource base upon which the agricultural economy depends, soil and water conservation is essential to long term agricultural viability. To the extent that GM crops are marketed as the solution to poor soils and water shortages, they distract farmers from the need to employ vigorous soil and water conservation practices, and thereby harm the environment.

Likely Damage to Beneficial Insects: Even scientists who generally view GM crops as benign admit that they cause some damage to populations of certain beneficial or desirable insects. People who are generally opposed to GM crops make claims of more extreme damage to the populations of such insects, including attributing them to be the cause of the honey bee colony collapse phenomenon (a claim that has not been scientifically proven to date). The indisputable fact is that research on the long term effects of GM crops on insect populations is on-going, the mechanisms at play within the ecosystem are complex, and much is still unknown. Individual Monarch butterflies who feed on milkweed flowers growing near plantings of Bt corn have been observed to die if pollen from the corn adheres to the milkweed flower and if that pollen expresses the Bt gene. However, some scientists argue that because the rate of expression of the Bt gene in corn pollen is very low, the risk of potential damage to overall Monarch populations is negligible even if some individual butterflies are indeed killed [12]. Researchers Conners, Glare, and Nap [12] note that even if insects don’t die directly from exposure to pollen containing the Bt transgene, some predator insects (who feed off prey insects who consume pollen from these plants) lack vigor and do not weigh as much as counterparts who feed off prey insects not fed with plants carrying the Bt gene. Many other examples of probable harm to insects due to GM crops are documented in the literature.

To the extent that more insect species are beneficial than are directly harmful to crops, and to the extent that GM crops appear (based on as yet incomplete evidence) to threaten both targeted pests and certain other insects indiscriminately, it is likely that wholesale production of GM crops do not represent a sustainable agricultural practice.

Herbicide Resistant “Superweeds”: It has been almost 20 years since the first Roundup Ready soybeans containing a gene to resist attack by glyphosate were commercialized in 1995. During this time, Nature has adapted. There are now numerous documented cases of various weed species that have become resistant to the effects of Roundup (glyphosate). Thus, the very problem that Roundup Ready soybeans were created to address — namely having crop plants able to resist damage from Roundup so that vulnerable weeds could be sprayed and destroyed — has been exacerbated. The case of waterhemp, a relative of pigweed, is a good example of an invasive weed species that has now become resistant to not one, but to three classes of herbicides, including glyphosates, ALS inhibiting herbicides, and PPO inhibiting herbicides [13]. Research is currently underway to engineer new varieties of crop plants that can resist damage from other classes of herbicides to which weeds have not yet become resistant. In this ever escalating “arms race” between modern genetic engineering and Mother Nature, I bet on Mother Nature to continuously “up the ante”. Continually having to re-engineer plants in order to try to stay ahead of Nature’s ability to adapt, rather than working in concert with Nature, is not sustainable. For many of these herbicide resistant weeds, the only sustainable option for control may be mechanical cultivation — the method used in the past, before the introduction of Roundup Ready crops.

Emergence of Bt Resistant and Secondary Insect Pests: In a situation similar to that involving herbicide resistant weed species, we are now seeing the emergence of certain Bt resistant insects that is attributable to the widespread use of the Bt transgene. In November 2009, Monsanto scientists found that the pink bollworm had become resistant to Bt cotton being grown in India. Since that time, resistant strains of cotton bollworms have been identified in Australia, China, Spain and the U.S. Monsanto recommends that as a strategy to delay the spread of this resistant bollworm, farmers interplant non-GM cotton with GM cotton, in order to dilute any resistant genes that may arise in these insects [14]. The operative word here is “delay”, since even Monsanto doesn’t claim that this tactic will stop the spread of the resistant strain of this insect altogether.

Secondary insect pests are also emerging. The definition of a secondary insect pest is a species that was never susceptible to Bt and thus can’t become resistant to it. However, these insect pests were previously kept in check by a balance within the ecosystem between themselves and various Bt susceptible species. Once these Bt susceptible species are reduced or eliminated, the secondary species experience a population explosion. Some of the secondary insect pests that are emerging in China and India include mirids, aphids, spider mites, and mealy bugs. Ironically, a 2011 survey of Chinese farmers indicates that they are collectively using nearly as much pesticide to keep these secondary pests in check as what was used previously to control the cotton bollworm prior to the introduction of Bt cotton [15].

Biodiversity: The importance of maintaining a reservoir of genetic diversity among food crops is well-understood by botanists. One lesson of the Irish Potato Famine in the 1840s was that if a particular cultivar becomes susceptible to attack by a virus or other disease vector, it is possible to go back into the gene pool and breed other varieties of the plants that are resistant to a particular disease. However, if we lose genetic diversity, and in particular, if we lose the genetic material contained in the wild relatives of our domesticated food crops, we endanger our future ability to respond to plagues like the Potato Famine. Various transgenes engineered into domesticated GM crops can be spread readily into non-GM relatives and closely related wild species. Hence the potential exists that without intentional strategies for preventing the spread of transgenes, the genetic purity of wild relatives of food crops will be forever lost. A 2010 study of wild canola in the U.S. Midwest, found the 83 percent contained the transgene used in domesticated canola to make it herbicide resistant [16]. Similarly, there is also great concern in Mexico over the use of Bt corn (maize), since Mexico is the geographical center of diversity of maize, and the home of its wild relatives.

Socio-political Implications: The tenets of sustainable agriculture include 1) “to satisfy human food and fiber needs”; 2) “to sustain the economic viability of farm operations;” and 3) “to enhance the quality of life for farmers and society as a whole.”

As relates to the first point, one of the most potent arguments made by proponents of GM agriculture is that without the use of GM crops, we will be unable to feed the world’s growing population. Yet upon further investigation, this claim becomes suspect. When the causes of modern famine are analyzed, we learn that the primary cause is not a fundamental shortage of food, but rather is due to social and political instability such as warfare, religious conflicts between various factions within developing nations, or corrupt and failing governments unable to administer food aid and food distribution programs effectively. How GM crops, per se, can address these issues any more effectively than conventional agriculture can is unclear. In fact, there is reason to believe that the use of GM seed worldwide will exacerbate certain social and political inequalities and make matters worse. One fact that supports this view is that GM seed is patent protected and must be purchased anew each year from a licensed distributor. The age-old practice of a farmer being able to hold back some of the previous year’s harvest as “seed corn” becomes illegal when GM crops are raised. This prevents the farmer from being self-reliant and forces him/her to shell out scarce cash resources to the seed distributor at the start of each growing season. This, in turn, does very little to “enhance the quality of life of the farmer,” or “to sustain the economic viability of farm operations.”

Another negative social impact of GM crops is that research into these crops has largely displaced traditional agricultural research directed at improving (through conventional means) the production of various indigenous crops important in the developing world. Such crops include millet, teff, and cowpeas. These “orphan crops” do not offer the potential for large profits, and therefore interest on the part of large agribusiness in investing in ways to improve crop yields is non-existent [17].

Final Thoughts — a Middle Ground?

As we have seen, GM crops present many potential issues that bring into question the wisdom of their use in agriculture. It is probable that some of the impacts of GM crops are not yet known because it will take some time before their effects on the larger ecosystem are fully understood. The Precautionary Principle — a fundamental tenet of environmental science — tells us, “When an activity raises threats of harm to human health or the environment, precautionary measures should be taken even if some cause and effect relationships are not fully established scientifically.” In other words, if there is a plausible chance of a negative impact, even if that negative impact has not yet been definitively proven, we should refrain from pursuing the activity until we can prove it to be harmless. Instead, U.S. agribusiness has pursued the opposite approach — it has proceeded in developing GM crops on the basis that it would cease doing so, only if harm from these could be proven definitively.

However, questioning whether we should employ GM crops in agriculture today is like closing the barn door after the horse has escaped (to call on an old farm adage). The case of GM crops is an example of scientific advances outpacing the public policy development needed to regulate them. Given the current widespread use of GM crops and the existing economics surrounding this multi-billion dollar industry, it is not likely we can eliminate GM crops altogether. We can, however, strengthen and expand our public policy to 1) create ways to better regulate existing GM plants, 2) monitor approvals of proposed new GM introductions, and 3) protect organic and non-GMO agriculture from the intrusion of GM crops. Pragmatists even within the sustainable agriculture movement agree that the present goal should not be to try to eliminate GM crops, but to strongly regulate them. Raymond P. Poincelot wrote a particularly forceful editorial espousing this view in the Journal of Sustainable Agriculture, which I recommend anyone interested in this topic read [18]. Some practical public policy actions that could be taken to facilitate the appropriate regulation and management of GM crops include:

  1. All GM crops raised for human consumption should be labeled as such. Meat from livestock raised on GM crops should also be labeled. The U.S. Food and Drug Administration (FDA) has resisted doing so, claiming a label would needlessly frighten the general public and that no evidence exists that GM foods are harmful when eaten. Indeed, of all the research into the possible negative effects of GM crops, the evidence to support direct harm to humans when consuming GM based foods is the weakest. Yet, that does not mean there are not effects that are harmful to the environment and thus indirectly harmful to humans. Labeling products as containing transgenes would raise the level of public awareness of the prevalence of these within the food chain. It might even spur the consumer to learn more about the larger impacts of GM foods to the environment. One could also argue that nutrition labels that appear on foods now could frighten consumers were they to see the list of food additives contained in processed foods, even though these additives have been tested and are generally considered safe. Yet, such labels are mandated. The same should be true for GM foods. Ultimately, the consumer has the right to know what is in her food and to decide for herself how to respond. Those skeptical of the U.S. regulatory system suggest that the U.S. agribusiness lobby has squelched the introduction of mandatory labeling of GM crops for fear U.S. consumers would reject them, cutting into profit margins, or worse yet, would insist these products be banned, such as what has occurred in portions of the European Union. These skeptics may very well be correct in their assessment.
  2. Mandated buffer zones. Certain crops like corn and sunflowers are notoriously promiscuous in their pollination habits. An organic farmer who attempts to grow non-GMO corn often has a difficult time doing so because his neighbor is growing GM corn in the next field. Buffer zones of several hundred feet, planted with unrelated vegetation, are recommended to stop the introduction of Bt genes into the organic corn. For sunflowers (raised for their oil) carrying the Bt gene, the required buffer zones are up to 1000 meters, to prevent cross-pollination with wild or non-GMO sunflowers. Right now the onus for providing such buffer zones lies with the organic farmer, who must remove some of his tillable land from production to create the buffer zone. Since many organic farmers tend to be smaller land holders, this onus is particularly damaging to the organic farmer’s profitability. One suggestion is to require the farmer growing GM crops to provide the buffer zone on his/her land.
  3. A stronger regulatory process for monitoring and approving GM crops. Within the U.S., regulatory responsibility for GM crops is split between the U.S. Department of Agriculture (USDA), the Food and Drug Administration (FDA), and the Environmental Protection Agency (EPA). EPA regulates biopesticides, including Bt. Therefore, any GM crops engineered to carry the Bt gene or other biopesticide genes must get EPA approval. Such approvals have become almost routine, even in light of recent evidence that the Bt transgene can harm some insect populations that are not pests. FDA regulates GM crops that are eaten by humans or food animals. Unless the crop contains foreign proteins that differ from the natural plant proteins in the non-GMO counterpart, FDA will almost without question designate it as “Generally Recognized as Safe.” The USDA regulates GM crops under the Plant Protection Act of 2000. Companies wishing to conduct field trials for a GM crop must either notify USDA or seek a permit. Whether notification or permitting is required depends on the potential risk a particular crop poses. Higher risk crops are those that have the potential to readily hybridize with wild relatives, stay in the ground for a long time, or which involve pharma crops (crops engineered to produce drugs for human consumption). Once the field trial stage is over and commercialization is sought, corporations can request that USDA “deregulate” their crop, effectively removing all future oversight. The exception to this deregulation is for pharma crops, which must remain regulated even while in commercial production [19]. The combination of the patchwork of regulatory authorities, understaffing of the enforcement arms of the three regulatory agencies, and over-reliance on data supplied by the corporations being regulated, (as opposed to testing by independent third parties), makes for a very weak regulatory system for GM crops in the U.S.

    On the international level, GM crop regulation is codified in the 2000 Cartegena Protocol. However, many GM crop producing countries, including the U.S., are not parties to the agreement. The Cartegena Protocol calls for informed consent on the part of countries who import GM crops. However, corporations who market GM seed have argued against disclosure of all but a minimum of information [3]. The result is that there is very weak international oversight and controls for GM crops.

     

  4. All future GM crop introductions should contain gene engineering specifically designed to mitigate impacts to the environment. For example, genetic engineers have the ability to build a dwarfing gene into a plant, along with whatever other traits they are building in for other purposes. Such a gene would produce a dwarf plant. The dwarf plant could flourish in its agricultural setting, producing whatever crop is intended because in such a setting there is no other competition. However, such dwarfs would be at a disadvantage in the wild because taller plants would block sunlight and not allow the dwarfs to survive. Thus, the dwarf plants would not tend to escape into the wild. In addition to intentional dwarfing other similar strategies would include intentionally designing plants with infertile seeds (to prevent spread outside the agricultural zone), or plants whose pollen is designed to be unpalatable to certain vulnerable insect species such as honey bees. While such engineered “enhancements” might cost Monsanto (and others) more, it would be considered the cost of doing business in a socially responsible manner.
    Region-specific bans on certain GM crops. For certain GM crops, there is not a uniform risk across all regions that they will hybridize with wild relatives and therefore spread their transgenes into the larger environment. If the wild relatives of the crop in question are found in Central or South America, for example, and if the GM crop is being grown in Iowa, there is little chance that the genetic make-up of the wild relatives will be affected. Such is the case with a crop like corn (maize). However, if wild relatives are present and if such relatives are particularly vulnerable to hybridization with the GM crop, then it makes sense to consider a regional (not total) ban on the GM crop. Such actions would mean an added level of complexity in the regulatory process, but would serve to better protect genetic diversity.

     

  5. Reduce or eliminate farm subsidies for corn, rice, wheat, soybeans, cotton, sugar cane and other agricultural commodity crops. It is not accidental that the crops that have led the GM revolution are the same crops that receive U.S. federal government subsidies. These subsidies distort the economics of growing such crops and incentivize big agriculture to grow more of them than if they were not subsidized. Since they then become the main cash crop, farmers are further incentivized to use agricultural practices that have a short-term benefit, even if they may have long-term downsides, e.g. Roundup ready soybeans, from whose use Roundup-resistant weed varieties have emerged. The fact that GM seed is patented and more expensive than non-GM seed is not a significant factor due to the distorted economics. It is worth noting that farmers growing crops that are not subsidized, such as most vegetables and fruits (tomatoes, lettuce, strawberries, apples, etc.) have not yet widely adopted GM varieties. In fact, one early GM introduction — the FlavrSavr tomato — was pulled from the market because consumers initially didn’t like it. Growers then made the rational economic decision to cease production. Is this connection between subsidies and the prevalence of GM varieties merely a coincidence then? Many would argue no. Once subsidies were removed, the decision to continue to use GM varieties would be made based on a more realistic assessment of their costs.

While we gaze at “Plowing with Oxen Teams,” it is easy for us to romanticize the way farming was practiced a century or more ago. Back then, there were no concerns over genetically modified crops and their long- term effect on the environment. However, farmers were also at the mercy of nature and had little recourse to deal with pests, weeds, or drought. As a result, starvation due to crop failures was much more common than today. A century ago, humans also had little or no access to life-saving drugs, including the drugs that biotechnology firms are now able to produce using pharma crops. So, like most things in life, we must seek balance in how we view and manage GM crops and the other fruits of the genetic engineering revolution in which we find ourselves. Unfortunately, the science that brought us GM crops developed faster than the public policies and regulatory structures intended to regulate it. We must now work to bring policy and regulation into alignment with this new technological revolution, in order to protect the well being of humans and the environment, alike. We must also structure our regulations in such a way as to offer citizens a choice of whether or when to consume GM products. Full disclosure through labeling and mechanisms to protect organic and non-GMO producers from contamination of their products with transgenes are essential. The purpose of this essay is not to demonize modern agribusiness. It is instead to encourage farmers to use a balanced approach to farming practices — employing sustainable practices where practicable, as well as judicious and selective use of GM crops and other ultra-modern technologies, where such technologies actually offer a societal benefit.

References and Further Reading:

  1. “Genetically Modified Crops,” Wikipedia, February 12, 2013, (http://en.wikipedia.org/wiki/Genetically_modified_crops)
  2. “Acreage NASS,” National Agricultural Statistics Board Annual Report, June 30, 2010. (http://usda.mannlib.cornell.edu/usda/nass/Acre/2010s/2010/Acre-06-30-2010.pdf)
  3. Gupta, A., “Transparency as Contested Political Terrain: Who Knows What about the Global GMO Trade and Why does it Matter?,” Global Environmental Politics, Vol. 10 Issue 3; August, 2010; Massachusetts Institute of Technology.
  4. “Supreme Court Appears to Defend Patent on Soybean,” reported by Adam Liptak, The New York Times, February 19. 2013.
  5. Maxmen, A., “Drug-making Plant Blooms,” Nature –International Weekly Journal of Science, Volume 485, Issue 7397, May 8, 2012.
  6. Kumar, G.B. Sunil; T.R. Ganapathi; et. al.; “Expression of Hepatitis B Surface Antigen in Transgenic Banana Plants,” Planta, Volume 222, Number 3, p. 484-493, October, 2005.
  7. “Genetically Modified Crops’ Results Raise Concern,” reported by Carolyn Lochhead, The San Francisco Chronicle, April 30, 2012.
  8. Gold, M., (July 2009). ‘What is Sustainable Agriculture?” (http://www.nal.usda.gov/afsic/pubs/agnic/susag.shtml). United States Department of Agriculture, Alternative Farming Systems Information Center.
  9. Food, Agriculture, Conservation, and Trade Act of 1990, Public Law 101-624, Title XVI, Subtitle A, Section 1603.
  10. “Promoting Sustainable Agriculture and Rural Development,” United Nations 1992 Earth Summit, Agenda 21, Chapter 14; Rio de Janiero, 1992.
  11. Leu, Andre, “Future Organic,” New Internationalist, Issue 368, June 2004, p. 34-35.
  12. Conner, A.J., Glare, T.R., and Nap, Jan-Peter, “The Release of Genetically Modified Crops into the Environment,” Part II, Overview of the Ecological Risk Assessment,” The Plant Journal, (2003), Volume 33, p.19-45, Blackwell Publishing, Ltd.
  13. Nordby, D., Hartzler, B., and Bradley, K., “The Biology and Management of Waterhemp,” Knowledge to Go Bulletin #GWC-13, Purdue University Extension, 2007.
  14. “Genetically Modified Food Controversies,” Wikipedia, February 11, 2013. (http://en.wikipedia.org/wiki/Genetically_modified_food_controversies)
  15. Zhao, J.H., Ho, P., and Azadi, H., “Erratum to: Benefits of Bt Cotton Counterbalanced by Secondary Pests? Perceptions of Ecological Change in China,” Environmental Monitoring Assessment, August 2012.
  16. “First Wild Canola Plants with Modified Genes Found in the United States,” Arkansas Newswire, University of Arkansas, August 6, 2010.
  17. Naylor, R.L., et al., “Biotechnology in the Developing World: a Case for Increased Investments in Orphan Crops.” Food Policy, Volume 29, Issue 1, p.15-44, 2004.
  18. Poincelot, Raymond, P., “From the Editor,” Journal of Sustainable Agriculture , Vol. 16(3), The Hayworth Press, Inc., 2000.
  19. Agricultural Biotechnology: Safety, Security, and Ethical Dimensions, Federation of American Scientists website, http://www.fas.org/biosecurity/education/dualuse-agriculture/2.-agricultural-biotechnology/index.html, March 26, 2013.

Coming in September 2013 is an essay on the natural gas industry’s current practice of hydraulic fracturing, i.e., “fraccing,” inspired by the 1911 Viggo Langer painting, ‘Oil Rigs in Baku at Caspian Sea.’
Copyright 2013 Deborah L. Jackman

By Deborah Jackman, PhD, PE, LEED AP™ - originally posted on 01/11/2013

trummerfrauen.jpg

The Painting and its Historical Significance:
“Trümmerfrauen” means “rubble women.” The painting, created in 1951 by Johvi Schulze-Görlitz, depicts a group of women sifting through the rubble of a bombed-out building, reclaiming bricks. The woman in the foreground of the painting is chiseling mortar from the bricks, so that they can be reused in subsequent rebuilding projects. The need for this reclamation speaks to the utter devastation inflicted by the Allies upon Nazi Germany at the end of World War II. That women, rather than men, were engaged in this back-breaking labor speaks to the fact that a large percentage of healthy, working-age German men were killed or captured during the war and were not available to help rebuild. Even the date of the painting is telling. While the war ended in 1945, even as late as 1951 significant areas of German cities still lay in ruin. Rebuilding continued well into the late 1970s in some areas. After the War, there was an estimated 14 billion cubic feet of rubble from destroyed buildings scattered throughout what was then West Germany [1]. All major German cities were affected. An estimated 80% of all historic buildings located in cities were destroyed. Housing was scarce because 6.5 million apartment units (out of a total of 16 million units) throughout West Germany had been destroyed in the bombing. While some of the rubble was reclaimed and reused in new construction projects, much of it was just piled up to create man-made hills. The rubble had to be consolidated so that still intact buried infrastructure such as sewer and water lines could be accessed during rebuilding. The Teufelberg (Devil’s Mountain), a mountain constructed of rubble located in Berlin, is 115 meters tall and is the second highest point in the city. There are even recreational sites located in modern Berlin, Leipzig, Frankfurt, and other cities used for snowboarding, paragliding, and rock climbing that have been created from these artificial urban rubble mountains.

Eventually, through hard work and resources supplied to it by the U.S. as part of the Marshall Plan, Germany did rebuild itself. Today, it has the largest economy in Europe, with a strong manufacturing base, a highly trained workforce, and low unemployment. Along the way–and likely due in part to its rebuilding experiences after the War– Germany has also become an international leader in the modern green building movement. Today, the average building in the U.S. uses approximately one third more energy than its German counterpart [3].

This essay will provide an overview of the modern green building movement, a summary of the various green building rating systems in use, and will look at the role that material selection and reuse plays in that movement.

The Green Building Movement—Definition and History:
At its most fundamental, a green building is one that minimizes negative impacts on the environment both during its construction and operation. Negative environmental impacts are those that contribute to the depletion of the Earth’s non-renewable resources or which degrade ecosystems. To understand how much impact buildings have on the environment, one need only consider that 40% of all energy used in the United States today is used to operate buildings. This amount of energy equals the amount of energy used for all transportation functions (automobiles, trucks, trains, planes, and buses) nationwide. Most of this energy comes from non-renewable sources and results in the generation of significant amounts of greenhouse gases. And, energy use is only one factor among several building-related factors that impact the environment. A number of rating systems and design protocols have been developed to assist architects and engineers in making sustainable choices as they design a building. Some of these “green” practices have also made their way into revisions to various building codes—a necessary step for institutionalizing green building strategies within the mainstream building design and construction industries. Before discussing specific green building strategies and rating systems, it is helpful to understand how these strategies and systems came to be. It is informative to look briefly at the history of the green building movement.

Most scholars of the green building movement mark the start of widespread interest in sustainable design with the publication of Rachel Carson’s Silent Spring in 1962. This seminal work spurred development not only of the green building movement, but of environmentalism in general. It directly led to the U.S. ban on DDT, and was a catalyst for much of the major federal environmental legislation of the 1970s, such as the Clean Water Act, the Clean Air Act, and Superfund legislation. Internationally, this heightened interest in the environment led to the 1972 Earth Summit, held in Stockholm, Sweden, and attended by representatives from 113 countries. As an outgrowth of this first Earth Summit, the Declaration of the UN Conference on Human Development was developed—a document that outlined 26 principles related to sustainability and human activity. Participants of this first Earth Summit also agreed to reconvene every 10 years to reassess progress toward achieving environmental goals [2].

Nearly concurrent with the first Earth Summit was the first Arab oil embargo of the U.S., also occurring in 1972. The Oil Producing and Exporting Countries (OPEC), a confederation of oil-rich nations, mostly in the Middle East, ceased oil exports to the U.S. for political reasons. This created a temporary petroleum shortage in the U.S., driving gasoline prices to record highs and creating national interest in alternative energy sources and in energy conservation. With the creation in 1977 of the Department of Energy (DOE) and the National Renewable Energy Laboratory, the federal government increased funding of research into various renewable energy technologies such as photovoltaic (solar) energy and wind energy– technologies that at the time were in their infancy, but which today have advanced to the point of being widely accepted alternatives to fossil fuel-generated electricity. The emphasis on energy conservation produced legislation to increase the fuel economy of automobiles. It also caused changes in building codes to ensure more energy efficient building envelopes. Once U.S. oil supplies appeared to regain a more secure footing starting in the early 1980’s, energy prices dropped and many U.S. consumers and businesses largely ignored energy conservation and alternative energy issues for the next two decades. Yet, many of the structural changes created during the oil embargo years—work of the DOE to fund energy research within universities, automotive fuel efficiency standards, and building code changes to foster building envelope efficiency—remained, and work continued in the background, largely out of public view.

A third key event in the evolution of the environmental and green building movements was the formation in 1987 of the Brundtland Commission. The Brundtland Commission was convened under the authorization of the United Nations General Assembly to create a white paper on what constituted sustainable development. The resulting report, “Our Common Future,” had as its principle premise that sustainable international development was the process by which we “meet the needs of the present without compromising the ability of future generations to meet their own needs” [2]. The Brundtland Commission’s work is perhaps most significant because it promoted action on the part of European and Asian nations to create and enforce standards to foster environmental responsibility. As impactful as the Arab oil embargo was to U.S. attitudes about energy conservation, the Brundtland Commission was probably a greater influence outside of the U.S. Hence, as popular interest in energy conservation waned in the U.S. during the 1980’s, it increased in Europe. Subject to higher energy prices than in the U.S., European businesses and consumers in the 1980’s and 1990’s had a much larger financial incentive to conserve energy and to explore alternative energy technologies.

The work of the Brundtland Commission spurred a movement among European architects to incorporate sustainable features into their buildings. By the early 1990’s, many European governments had mandated requirements for minimum energy efficiency standards in buildings. Building designs featuring sustainable elements became prominent in the work of such well-known European architects as Norman Foster and Willem Jan Neutelings [3]. U.S. architects recognized this emerging European design trend and realized the need for the development of sustainable building standards in the U.S. A principle difference, however, between Europe and the U.S. is the degree to which the respective governments practice centralized planning, and regulate building and development. The degree of regulation is much higher in Europe. So, whereas energy efficiency standards for buildings were mandated by many European governments by the 1990’s, architects and engineers seeking to develop consistent standards for green building in the U.S. had to largely rely on the development of voluntary, industry-based standards. In 1993, the United States Green Building Council (USGBC) was formed as an outgrowth of discussions conducted during the American Institute of Architect’s (AIA) World Congress of Architects meeting in Chicago of that year [2].

The USGBC unveiled the first version of its Leadership in Energy and Environmental Design (LEED) green building rating system in 1998, after several years of discussions among its membership. The development of the first version of LEED was stimulated by a memo of understanding between AIA and the DOE, finalized in 1996 during the Clinton administration. The memo of understanding called for the establishment of a roadmap for sustainable buildings for the 21st century and promised government support in the form of grants for research related to this goal. An executive order made by President Clinton in 1998 mandated all government buildings to improve their energy management and to incorporate “environmentally preferred” material choices whenever possible [2]. While not directly impacting private buildings, this executive order provided impetus to the development of much of the intellectual infrastructure needed for a more integrated approach to sustainable design within the U.S. in subsequent years. LEED was revised and updated to Version 2.0 in 2000 and again, to Version 2.1 in 2002, Version 2.2 in 2005, and Version 3.0 in 2009, all in response to an increased interest in green building and to efforts to apply consistent metrics to what it means for a building to be “green.” In the early 2000’s, after 9/11 and the ensuing Iraq war, energy prices again rose and public interest in renewable energy and energy conservation re-emerged. Around this same time, a number of prominent extreme weather events occurred world-wide (droughts, hurricanes, floods), which many attributed to global climate change caused by greenhouse gases. The cumulative effect of all of these factors is that today interest in green building is high. Green buildings are no longer viewed as exotic, but as mainstream. Because more architects and designers are now familiar with the strategies and tenets of green design, design premiums that were previously assigned to certified green buildings have greatly diminished. Owners and architects alike understand that on a life cycle cost basis (which considers both construction and on-going operating costs), a well-designed green building is actually less expensive than one that is designed using older conventional standards.

Green Building Rating Systems:
Especially in the early days of the green building movement designers were not always clear on what constituted a “green” or sustainable building design practice. A strategy or material that initially seemed like it might be the greenest choice turned out, after further analysis, to be less green than other alternatives. The need to establish objective standards for what building design practices were sustainable was the driver behind the establishment of various building rating systems. Given below is a brief summary of the major green building rating systems in use today and their primary criteria.

  • BREEAM (established in 1988 by the British Building Research Organization)
    Even though LEED is the best known rating system in the United States, it is not the oldest. BREEAM was established by the British in 1988 and is the oldest green building rating system in wide spread use. It was directly inspired by the same wave of environmental activism in Europe that surrounded the formation of the Brundtland Commission discussed above. It is used widely in Great Britain, Germany, France, Spain, and Italy. It assesses buildings in the following areas:

     

    Credits are awarded in each category, the credits weighted relative to the importance of each category, and a building receives one of four ratings: Pass, Good, Very Good, or Excellent. A certificate is awarded that can be used for promotion by the building owners. BREEAM covers residences, offices, and industrial facilities, with different assessment methods for each category.

    1. building management (during construction, commissioning, and operation);
    2. energy use;
    3. health and well-being of workers and occupants;
    4. water and air pollution generated by the construction and on-going operations of the building;
    5. transport (CO2 generated to travel to and from the building);
    6. land use (greenfield and brownfield sites);
    7. ecology (protection of sensitive building sites);
    8. material (low impact materials based on life cycle analysis); and
    9. water (consumption and efficiency).
  • LEED (Leadership in Energy and Environmental Design, established in the U.S. by the USGBC in 1998 with updated versions since)
    This is the major rating system used in the U.S. It consists of seven categories of evaluation criteria:

     

    Each category has a maximum number of points assigned to it and if a building design and construction process meets a given criteria, it earns points for that category, up to the maximum limit. Total points are then calculated and a building earns a Certified, Silver, Gold, or Platinum rating. Like BREEAM, a certificate is issued that the owner can use for publicity purposes. LEED ratings systems for new commercial construction, core and shell construction, and schools are available. While the topics are organized and subdivided somewhat differently, the fundamental parameters which determine building sustainability are very similar between BREEAM and LEED. One significant difference between the two is in how they were developed. BREEAM was created by a British national standards agency and then was adopted by various developers. LEED, on the other hand, was developed by consensus within the private sector by conversations and debate between architects, engineers, and other interested parties. Other important points related to LEED include the fact that the regional priority credit category is new with LEED Version 3.0 and was added to address the criticism that there needed to be flexibility built into LEED to allow for regional differences. Also, in going from LEED Version 2.2 to Version 3.0, categories were reweighted to give greater importance to energy conservation and water conservation—arguably, the factors having the greatest environmental impacts.

    1. sustainable sites;
    2. water efficiency;
    3. energy and atmosphere;
    4. materials and resources;
    5. indoor environmental quality;
    6. innovation and design process; and
    7. regional priorities.
  • Green Globes (originated in Canada but becoming popular in the U.S)
    Green Globes is questionnaire-driven, with questions asked of the designer and builder related to seven categories:

     

    Again, except for the organization of the categories being slightly different, the essence of what constitutes valid criteria for a sustainable building project is similar to LEED and BREEAM. One major difference is that in addition to designers answering the questionnaire, the building project is only certified once a third party auditor does a site inspection/audit to verify that the features reported were in fact implemented in the building. Neither LEED nor BREEAM actually requires an audit of the final building; both rely on accurate self-reporting from the designers. Another difference between Green Globes and LEED is that in Green Globes the project is not penalized if a particular point is unavailable to the project. For example, LEED gives a point for a project built on a Brownfields site. This point counts toward the point total within the Sustainable Site category. If the location for the project precludes it being on a Brownfields site, there is no way for the project to regain that point and it may be unable to achieve the highest rating even if it is exemplary in all other respects. Green Globes’ points are adjusted based on project location. For these reasons, and also because some see LEED as increasingly driven by monetary interests within the USGBC, many prefer Green Globes.

    1. project management;
    2. site;
    3. energy;
    4. water;
    5. resources, building materials, and solid waste;
    6. emissions and effluents; and
    7. indoor environment.
  • CASBEE (Japan) and Green Star (Australia)
    Space precludes a detailed description of these in this essay. The interested reader is referred to [4] for more information on these two rating systems and also for more detail on LEED, BREEAM, and Green Globes.

Regardless of which of these rating systems is used, they have several characteristics in common. All account for– in varying degrees and using different algorithms and point systems– building energy usage, water usage, materials usage, ecological impacts and site considerations, and occupant well-being. None are perfect and each can be manipulated in ways that can actually produce a less green outcome, from an objective standpoint. For example, LEED has been criticized as stifling true design innovations by incentivizing designers to make certain design choices just to earn points needed to attain a higher level of certification, even if those design choices don’t contribute optimally to the sustainability of the overall design. Critics argue that truly innovative solutions are passed over because they don’t earn the designer or owner LEED points. To some extent, USGBC has attempted to address such criticisms by incorporating innovation points into the LEED system, but this is not a perfect solution. Ultimately, the effectiveness of any of these rating systems in ensuring an optimal building design lies in the skill and common sense of the design team employing them. There is no “one size fits all” solution to green building design; solutions are dependent on the location and use of the building, owner preferences, the budget, and other factors. The designer must optimize the sustainability of the building within the context of these other factors.

Building Material Reuse and Recycling:
Since the environmentally efficient use of materials is a parameter used in all the major green building rating systems described above, and since our subject painting directly speaks to the reuse of bricks, let’s briefly review how building material selection impacts the modern green building movement.

First, it is worth taking a moment to define the terms “reuse” and “recycling.” While sometimes mistakenly used interchangeably, they are technically different. “Reuse” of materials is taking a used building element—a brick, timber, flooring, doors, or other building materials or architectural elements and simply reusing them in another structure for the same purpose or similar purpose. Reuse can involve a cleaning or machining step (e.g. chipping mortar off bricks or resizing a timber using a saw), but does not involve reprocessing the material and remanufacturing it into another form. “Recycling” of materials is taking a used building element and reprocessing it such that it becomes raw material for a distinctly different finished product. A good example of a commonly recycled building element is steel. A steel beam from a demolished building can be sent to a steel mill, melted down, and reformed into another steel object, such as sheet goods, that can be used in automobiles or other products totally unrelated to the building process. In this context, the bricks in our subject painting are destined for reuse, rather than recycling.

A related point is that just because a building product is recycled or reused does not mean it is the most sustainable choice for a given building project. There are five generally recognized factors that can contribute to how green a building product is [5]:

  1. The product is made from “environmentally attractive” materials such as those that are salvaged, recycled, renewable, minimally processed or harvested in a sustainable manner.
  2. The product is “green” because of what it does NOT contain, for example treated lumber that doesn’t use conventional preservatives shown to harm the environment.
  3. The product reduces environmental impacts during construction, renovation, or deconstruction because of the way it is designed, e.g. certain types of modular building panels that reduce site disturbances during installation and which are easy to disassemble and reuse.
  4. The product helps to reduce negative environmental impacts during building operation, e.g. products that make the building very energy or water efficient and thereby increase overall building sustainability.
  5. The product contributes to a safer indoor environment within the building both for workers during construction and for occupants, e.g. low VOC paints that don’t release harmful fumes.

Sometimes a new product that contributes significantly to building energy efficiency is greener than a reused element that would contribute to a less energy efficient building. New windows versus reused windows are a good example. The new window, with high efficiency glass, would generally be considered the greener choice. Some material choices espouse more than one of the five factors listed. Generally speaking, the more of the five listed factors a single building material product espouses, the more likely it is to be the most sustainable choice for a given situation.

An integrated method for determining in an overall sense how sustainable a given building material choice is uses the Life Cycle Assessment (LCA) methodology. LCA is able to factor in the effects of multiple attributes—e.g., recycled content, high energy efficiency, low impact manufacturing process, etc.– and predict which material choices have lowest environmental impacts overall. LCA requires a detailed accounting of the raw material and energy inputs through out the life cycle of the product and also knowledge of emissions generated during product manufacture, transport, installation, use, and salvage/demolition. The life cycle of the product starts at the point where any raw materials needed to manufacture the product are mined or harvested and continues on until the building product is removed from the building many years later during demolition. The major downside to LCA is that we do not currently have sufficiently detailed databases quantifying raw material inputs, energy inputs, and emissions on many common processes and products. However, as research in the area of sustainable construction continues, such databases are growing over time.

One result of an LCA analysis on a building product is knowledge of that product’s embodied energy. Embodied energy is the total energy consumed in the acquisition and processing of raw materials, including manufacturing, transportation, and final installation. The lower the calculated embodied energy of a building product is, the lower its environmental impact. Reused products usually have lower embodied energy than newly manufactured products of the same type because the energy that went into the original manufacturing steps, (e.g. kiln firing a brick), do not have to be repeated before that product can be reused. It is interesting to note that according to the U.S. EPA [6], the U.S. manufactured over 8.3 billion clay bricks in 2001. Each brick has an embodied energy of approximately 4300 BTU [7]. Were we to reuse even a fraction of these bricks rather than simply manufacture them anew, the potential energy savings would be huge. At least in the case of bricks reuse makes tremendous environmental sense. One obstacle in the way of building materials reuse is the inability to match those who have materials that are available to be reused with those who wish to reuse them. This obstacle can be addressed more easily now than in the pre-Internet days through the development of searchable on-line materials exchanges such as the example shown in [8].

Final Thoughts:
A typical building has a life expectancy of 30 to 50 years or more, depending on its use, historical value, and other factors. Therefore, design decisions made today on a building project will influence energy consumption, water consumption, site ecology, and overall sustainability for decades. Arguably, wise design decisions are critical to the long term health of our environment. This brief overview of green building rating systems and of the sustainability of building materials is intended to increase awareness by users and consumers of buildings—homeowners and commercial developers alike—of the critical importance of the green building movement. By reclaiming used bricks from the rubble of World War II our Trümmerfrauen were employing aspects of sustainable design and construction, albeit because of the exigency of their circumstances, rather than due to any conscious efforts on their part to be “green.” Yet the Trümmerfrauen painting provides us with an interesting historical segue to better understanding the significance of the sustainable building movement in our own times.

References and Further Reading:

  1. Leick, R., Schreiber, M., and Stoldt, H.; “Out of the Ashes – A New Look at Germany’s Postwar Reconstruction,” Der Spiegel Online International, August 10, 2010. (http://www.spiegel.de/international/germany/out-of-the-ashes-a-new-look-at-germany-s-postwar-reconstruction-a-702856.html)
  2. Korkmaz S., Erten D., Varun Potbhare M.; “A Review of Green Building Movement Timelines in Developed and Developing Countries to Build an International Adoption Framework,” Proceedings of the Fifth International Conference on Construction in the 21st Century (CITC-V), May 20-22, 2009, Istanbul, Turkey.
  3. Ouroussioff, N., “Why Are They Greener Than We Are?”, The New York Times Magazine, May 20, 2007.
  4. Kibert, C.; Sustainable Construction—Green Building Design and Delivery, 3rd Edition, John Wiley and Sons, Inc., Hoboken, New Jersey, 2012.
  5. Wilson, A., “Building Materials: What Makes a Product ‘Green’?”, Environmental Building News, January, 2000.
  6. “Background Document for Life-Cycle Greenhouse Gas Emission Factors for Clay Brick Reuse and Concrete Recycling,” EPA530-R-03-017, November, 2003.
  7. “Sustainability and Brick,” Technical Notes on Brick Construction-TN 48, the Brick Industry Association, Reston, VA, June 2009.
  8. The Used Building Materials Exchange, http://build.recycle.net/exchange/.

Coming in Spring 2013 is an essay on sustainable farming practices, inspired by William Watson’s oil on canvas work, “Plowing with Oxen Teams.”

fantastic river landscape.jpg

By Deborah Jackman, PhD, PE, LEED AP™ - originally posted on 09/18/2012

The Painting and its Historical Significance:
No series of essays featuring the works from the Man at Work Collection would be complete without including one of the seminal works in the collection—the 1609 oil painting by Flemish artist Marten van Valckenborch, “Fantastic River Landscape with Ironworks”. Not only is it one of the oldest works in the Collection, but it depicts fledgling elements of the steel industry, an industry that underpinned much of the Industrial Revolution and the development of modern society. It is also an industry that has enormous environmental impacts, and which, in recent years has undergone significant changes to improve its sustainability.

On the left bank of the river is the ironworks. The ironworks is comprised of groups of workers who offload iron ore from boats; a blast furnace used to convert iron ore to elemental iron; a forge shop used to produce wrought iron implements from the elemental iron; and lime quarrying on the hillside above the ironworks. The blast furnace is the structure in the middle left foreground with the large, rectangular stone chimney and one water wheel. The forge shop is located just to the left of the blast furnace in the structure without walls, with the pyramidal thatched roof, attached to the building with two water wheels. (The water wheels in both the case of the blast furnace and forge were used to power air bellows which blew the air required for both processes.) The lime being quarried on the hill side was used in the blast furnace during the chemical reduction of iron oxide to elemental iron. On the right bank of the river, farming activities are depicted. The contrast between the activities on the opposite banks of the river is evidence that the time period in which the painting was created was one of transition. The early 17th century represents the start of the Industrial Revolution and a move away from an agrarian society. For the purpose of this essay, we will focus on the activities on the left bank of the river—those associated with iron making.

In 1609, iron produced in blast furnaces was transformed into wrought iron implements such as plowshares, horseshoes, and other hardware items, by blacksmiths at the forge. In 2012, blast furnaces are still used, but the iron produced in them is nearly all used for the subsequent manufacture of steel, as discussed in the section below. The blast furnace depicted in the painting is thus a focus of our study because it is a technology that has endured over the last 400 years (albeit with improvements along the way) and because its operation has the greatest environmental impacts of any process associated with steel production.

An Introduction to Steel Production:
Modern steel plants vary from plant to plant in their details of operation. But, the general process used to produce steel is common to nearly all modern plants [1]. This general process includes the following steps:

  1.     Various material handling practices and technologies to bring the needed raw materials to the plant and prepare them for further processing. The raw materials include iron ore, limestone, and fuel, usually coking coal. Depending on the exact processes used in a given plant, the iron ore is processed before being introduced into the blast furnace by crushing, pelletizing, and/or concentration. The general term used to prepare the iron for the blast furnace is beneficiation. Different plants use different beneficiation processes, which vary in complexity and which depend, in part, on the type and quality of iron ore being used. Limestone—also used as a reagent in the blast furnace—must be crushed and screened. Coal brought into the steel plant must be converted to coke in order to prepare it properly for the chemical reaction for which it will be used when introduced into the blast furnace. Therefore, most modern steel plants incorporate coking ovens. The coking process introduces additional process steps, and consumes some of the energy originally stored in the coal. Hence, coking, while necessary in conventional steel making, lowers the overall energy efficiency of the steel production process, and, from a life cycle assessment standpoint produces additional environmental impacts.
  2. Chemical reduction of the iron oxides contained in the iron ore to elemental iron. This is most commonly accomplished through the use of a blast furnace, although recent advances in technology, discussed below, have produced alternate methods of achieving reduction of the iron oxides to elemental iron which are less energy intensive and less polluting. The elemental iron produced in the blast furnace is commonly called pig iron. Upon leaving the blast furnace, the pig iron typically contains too much carbon content to be used in steel products. It is suitable only to be used as cast iron.
  3. Controlled oxidation of the pig iron in a steelmaking furnace to lower its carbon content and to produce carbon steel with the desired metallurgical composition. Steelmaking furnaces typically fall into one of three categories—a basic-oxygen furnace (BOF), an open-hearth furnace (OHF), or an electric-arc furnace (EAF). The basic-oxygen furnace is the type most commonly found in large, integrated steel making plants in the U.S. In the steelmaking furnace, molten pig iron is exposed to air in a controlled, basic (i.e. high pH) environment and various trace elements such as chromium, manganese, nickel or molybdenum may be added to the molten metal to produce various steel alloys. Since most steel recovered from demolished buildings and other objects is recycled today, scrap steel is also commonly introduced to the steelmaking furnace, to replace all or part of the pig iron used. The processing of recycled scrap steel, as opposed to virgin pig iron, favors the use of an EAF, for reasons described below.
  4. Various forming and heat treating processes to produce the desired end products. These processes include rolling, casting, forging, drawing, and extruding the molten steel into such products as bars, plates, wire, tubular products like pipe, and other structural shapes.

Of the four steps outlined above, the two which have the largest environmental impacts are the iron reduction step involving the blast furnace and the operation of the steelmaking furnace. These environmental impacts arise from the enormous amounts of energy consumed during the two processes and from the generation of large amounts of toxic exhaust gases, contaminated wastewaters, and solid waste. We will therefore focus on understanding these two processes in more depth, so as to be able to understand ways to minimize the environmental impacts associated with them.

The blast furnace, contrary to what its name suggests, is more than just an oven or furnace for heating the raw materials. It is a chemical reaction vessel in which iron oxide is reduced to elemental iron. The term commonly used for this reduction reaction of iron oxides to iron is smelting. A charge containing iron ore, flux (usually limestone), and fuel (usually coke in modern plants) is introduced to the top of the blast furnace, while air (sometimes enriched with oxygen) is blown into the lower portion of the furnace. The chemical reaction takes place through out the body of the blast furnace. The material charge moves downward, reacting with the hot combustion gases, rich in carbon monoxide, moving upward. The end products are molten pig iron and ****, which exit the bottom, and flue gases which exit the top of the furnace. The chemical reactions involved can be summarized as follows:

2 C(s) + O2(g) → 2 CO (g)(1)

[Coke and oxygen are converted to carbon monoxide in an incomplete combustion reaction]

3 Fe2O3(s) + CO(g) → 2 Fe3O4(s) + CO2(2)
Fe3O4(s) + CO(g) → 3 FeO(s) + CO2(g)(3)
FeO(s) + CO(g) → Fe(s) + CO2(g)(4)

[Multi-step chemical reduction of iron (+3) oxide to elemental iron using carbon monoxide as the reducing agent]

The net reaction is:

Fe2O3 + 3 CO → 2 Fe + 3 CO2(5)

Careful inspection of the above chemical equations indicates that carbon monoxide is the limiting reagent. Consequently, there needs to be a way for more carbon monoxide to be generated in the body of the reactor (blast furnace) as the material charge moves through in order to keep the reaction going. That is the purpose of the flux (limestone):

CaCO3(s) → CaO(s) + CO2(g)(6a)
CO2(g) + C ↔ 2 CO(6b)

In reactions (6a) and (6b), the limestone is decomposed into calcium oxide and carbon dioxide, and then the carbon dioxide reacts with the carbon from the coke to generate more carbon monoxide. The calcium oxide generated by the decomposition of the limestone typically reacts with impurities in the iron ore such as silica to form various types of mineral ****, which are byproducts of the blast furnace process. The most common **** produced is calcium silicate:

SiO2 + CaO → CaSiO3

Calcium silicate has properties similar to Portland cement and is used as a replacement for a portion of Portland cement in some concrete mixes. This use provides a natural route for reclaiming and recycling the **** produced in the blast furnace reaction, thereby minimizing the impact of this particular solid waste byproduct on the environment. (The interested reader may wish to read Installment Three of this essay series, “ ’The Experience of the German Autobahn’—A Discussion of Sustainable Pavement Technologies,” for a more in-depth description of how the use of **** in concrete mixes used in highway construction can minimize the environmental impacts of road construction.)

It is apparent that the blast furnace process is incredibly energy intensive, requiring large amounts of carbon-based fuels, and producing significant amounts of greenhouse gases in the form of carbon dioxide. According to Rubel, et al, [2], 75% of all energy consumed in an integrated steel plant is consumed in the form of coke used during the blast furnace process. 15 gigajoules of energy are used in the blast furnace process required to produce one ton of steel. In 1609, the blast furnace depicted in our painting probably used charcoal, produced by burning wood in an oxygen-starved environment. Coke, derived from coal, is used today. Both charcoal and coke burn at temperatures higher than the materials from which they are derived. This higher temperature promotes a more efficient reduction reaction. In addition to carbon monoxide and carbon dioxide, the exhaust gases from the blast furnace contain significant amounts of particulate matter, heavy metals, and other pollutants. In the time of van Valckenborch, no one worried about air emissions, but today, increasingly stringent environmental regulations require steel producers to employ various pollution abatement technologies, which are expensive and which add complexity to the process.

The pig iron produced by smelting in the blast furnace typically has around 4% by weight carbon content. The desired carbon content of carbon steel is around 0.5% to 1%, depending on the particular type of steel [1]. The pig iron also contains contaminants such as sulfur, silica and phosphorus. The steelmaking furnace incorporates a process whereby excess carbon is oxidized and removed, in the form of carbon dioxide, and where other impurities can be reacted and removed as ****. It also provides a convenient point in the process where various metal alloys can be added to produce steels with enhanced chromium, molybdenum, or nickel content (alloy steels). As mentioned above, the three styles of steelmaking furnaces encountered today are (1) the Open Hearth Furnace (sometimes called the Siemens Process); (2) the Basic Oxygen Furnace (BOF) (sometimes called the Bessemer Process); and (3) the Electric Arc Furnace (EAF). In the Open Hearth Furnace (OHF), the molten pig iron is introduced into a vessel lined with a basic refractory material, such as magnesite brick, a material capable of withstanding the high temperatures and one that does not introduce acidic byproducts into the process. Into the refractory vessel gasified fuel and excess air is introduced, along with a limestone charge. During the ensuing combustion process, carbon residing in the carbon steel is oxidized and other trace impurities react with the limestone to produce various types of ****. The Open Hearth process requires a fuel gasifier if coal is to be used as the primary fuel source. A distinguishing feature of the OHF is a series of passageways in the refractory brick to allow the brick to be preheated by hot exhaust gases. This allows the OHF to reach very high temperatures. In the Basic Oxygen Furnace (BOF), the molten pig iron enters a reaction vessel into which pure oxygen is blown through the molten iron mass. A limestone charge is also added. Oxidation of carbon to carbon dioxide occurs and other impurities are converted to **** in the presence of the limestone. Because pure oxygen is used instead of air, no external fuel source is needed to promote the oxidation (combustion) of carbon to carbon dioxide. The oxidation reaction of carbon to carbon dioxide is exothermic, so the heat generated by the reaction itself is sufficient to sustain the temperature in the reaction vessel. In this way, the BOF process is different from the OHF process. Because BOF does not require an external fuel source and doesn’t require a fuel gasification system, it has largely replaced the OHF process in most modern, integrated steel production facilities. However, because BOF does not have an external fuel source, it is limited as to how much scrap steel it can process, unless that scrap steel is first melted. The BOF process is optimized around the use of molten pig iron generated by the blast furnace. Thus, in the modern steel plant, the use of a blast furnace and a BOF are tightly linked. The third type of steelmaking furnace is the Electric Arc Furnace, (EAF). It uses electrical current introduced into the iron or recycled steel by large electrodes to melt the metal. The metal charge is spiked with burnt lime prior to being placed in the furnace. The lime acts as flux, promoting the conversion of impurities in the iron or steel into ****, which can subsequently be separated from the steel. Oxygen is blown into the furnace during operation to convert carbon into carbon dioxide, just as in the case of the BOF and the OHF processes. Because the EAF is designed to be able to melt its charge before oxidation of excess carbon occurs, it is uniquely capable of handling 100% recycled steel and does not need a supply of pig iron in order to produce steel. Because the energy source is 100% electrical energy, rather than coal or natural gas, the EAF process can also theoretically be run using electricity generated from nuclear or renewable sources, thereby allowing it to operate with a much smaller carbon footprint.

Recent Technological Developments to Increase the Sustainability of Steel Production:
The steel industry has always known that its processes are energy intensive and as a result have significant negative environmental impacts. Consequently, incremental improvements to both the blast furnace and BOF processes have occurred through out the last century in an effort to recover energy. These efforts have not, until quite recently, been directed at reducing the processes’ carbon footprints, but rather at reducing production costs. Nonetheless, a number of energy recovery strategies have been employed, particularly with blast furnace processes to reduce the cost of their operations, (and incidentally to also reduce their carbon footprint). One of the most basic strategies has been to use the hot exhaust gases from the blast furnace and waste heat from other places in the steel plant to preheat the air entering the furnace. Recently, a new design called the Top-Gas Recycling Blast Furnace has been pilot tested in the EU. This technology employs carbon capture and storage of exhaust gases from the blast furnace. It is projected to be fully commercialized by 2020 [3].

Since the Clean Air and Clean Water Acts were first passed by the US Congress in the early 1970’s, during the administration of President Richard M. Nixon, US steel makers have had to also employ various pollution abatement technologies. These technologies are well documented in Reference [4]. European and other first world countries have had similar pollution control regulations in place for steel manufacturers for much of the last half century. However, treating contaminated air and water streams after they have been generated in the steel making process is inherently less sustainable than preventing that pollution in the first place. Therefore, the newest and most innovative steel production processes seek to minimize energy use and prevent pollution, over the life cycle of the process, rather than treat and remediate pollutants after they are generated.

One such process has been developed by Siemens—a patented process known as the COREX® process. This process involves a modified blast furnace process, the details of which are proprietary. COREX® eliminates the need for coking the coal prior to the iron reduction step and also eliminates the need to sinter the iron ore prior to reduction. By eliminating the need for coke ovens and sintering plants, overall environmental impacts are reduced on a life cycle assessment basis. Overall energy consumption of the steel making process is also reduced because conventional coking reduces some of the useable chemical energy originally stored in the coal, in exchange for providing the higher combustion temperatures, needed in a conventional blast furnace. Reference [5] provides additional information on the life cycle assessment analysis performed by Siemens on its COREX ® process.

Even more promising than COREX®, from an energy conservation and environmental impacts perspective, are Direct Reduced Iron (DRI) processes [6]. This family of processes allows for the direct reduction of iron ore (in the form of lumps, pellets, or fines) by a reducing gas (either a mix of hydrogen and carbon monoxide) or by non-coking grades of coal. The process occurs in the solid phase– the iron ore is not melted, as in a blast furnace process. Because there is no phase change during the process (i.e. no melting occurs), the process is inherently less energy intensive. Furthermore, the solid-phase product produced from the DRI process can then be fed directly to an EAF furnace, further reducing the need for primary fossil fuel use. A final advantage of DRI is that because a source of coking-grade coal is not required, it can be conducted in geographical locations where low grade coal or other fuels are available. The ability to make steel in the same region where it will be used by combining DRI and EAF technologies reduces transportation costs and thereby the embodied energy and environmental impact of the product over its life cycle. Reference [7] provides a detailed Life Cycle Assessment (LCA) analysis of the material flows involved in the conventional steel industry. It shows that the traditional methods of making steel which involve transporting raw materials and finished product across large geographical distances is unsustainable, and that the steel industry must move to a more localized production model. Such localized steel production has taken the form of “mini-mills”. Mini-mills require far less capital investment, and unlike a blast furnace, which cannot be shut down for years at a time (because the start-up energy demand is so high), mini-mills are able to be operated on-demand. DRI is somewhat less rich in elemental iron—88% as opposed to 95% iron content from blast furnace processes and it contains more silica impurities than pig iron from a blast furnace because blast furnace **** is not removed. But, these disadvantages are largely outweighed by other factors and can be compensated for by various pre- and post-treatments. One economic driver for the increased use of DRI processes is the growth of the scrap steel market. Scrap steel is now highly sought after for use in EAF- based mini-mills and the price of scrap steel has increased significantly over the last several decades. DRI is therefore desirable as an alternate feedstock for these mini-mills.

Final Thoughts– The Connection between Economic Competitiveness and Sustainable Production Methods:
Over the last 30 years, the amount of energy required to produce a ton of steel has been reduced by 50%, and today, over 70% of scrap steel is recycled [8]. However, until quite recently, these improvements in energy efficiency and recycling were not due to environmental consciousness on the part of steel companies so much as due to a desire to reduce production costs. They were largely market-driven. This illustrates a key point regarding sustainability– that it often can be accomplished in parallel with cost reductions and increased profitability, and not in opposition to them. An older and largely obsolete view of environmentalism is that it is always an added cost, over and above other production costs. This is clearly not the case in the steel industry, which has embraced sustainability as a means to remain viable into the 21st Century. Reference [2] provides a detailed analysis of how sustainable practices can be used to improve profitability within the steel industry over the next decades. Such industry trade groups as the World Steel Association (www.worldsteel.com ) have devoted considerable resources to developing more efficient and sustainable models for steel production and to sharing them with their member companies. Just as the blast furnace technology represented in van Valckenborch’s 1609 painting helped to lead humanity into the modern industrial age, efforts at increased sustainability by the modern steel industry can help forge an integrated, green economy of the future.

References:

  1. The Making, Shaping and Treating of Steel, 10th Edition, United States Steel Corporation, edited by William T. Lankford, Jr., Norman L. Samways, Robert F. Craven, and Harold E McGannon, 1985.
  2. “Sustainable Steelmaking—Meeting Today’s Challenges, Forging Tomorrow’s Solutions”, Rubel, H.; Wortler, M.; Schuler, F.; and Micha, R. ; The Boston Consulting Group, July, 2009.
  3. http://www.ulcos.org/en/research/blast_furnace.php, information provided by the Ultra Low CO2 Steelmaking initiative.
  4. Pollution Prevention Technology Handbook, edited by Robert Noyes; p. 168-192, Noyes Publications, Park Ridge, New Jersey, 1993.
  5. Siemens: A better ecobalance in steel production – Pig iron production with COREX® and FINEX®
  6. “The Increasing Role of Direct Reduced Iron in Global Steelmaking,” Grobler, F., and Minnitt, R.C.A., The Journal of the South African Institute of Mining and Metallurgy, March/April, 1999, p. 111-116.
  7. “Iron Ore and Steel Production Trends and Material Flows in the World: Is this Really Sustainable?”, Yellishetty, M., Ranjith, P.G., and Tharumarajah, A., Resources, Conservation and Recycling, Volume 54 (2010), p. 1084-1094.
  8. World Steel Association: Sustainable Steel: At the core of a green economy

Coming in January 2013, is an essay based on Johvi Schulze-Görlitz’s 1951 oil-on-canvas painting, “Trümmerfrauen” (Rubble Women). The essay will look the evolution of materials recycling in the construction industry and the growth of the green building movement.?

experience-of-the-german-autobahn.jpg

By Deborah Jackman, PhD, PE, LEED AP™ - originally posted on 06/04/2012

The Photograph and its Significance:
The subject work being considered in this essay is not a painting but a photograph taken by the German photographer, Hermann Harz, in 1935. It is one of several in a series of dye-transfer photographs which highlight the German Autobahn system.

The Nazi regime used photographs to document its major construction projects—the Autobahn construction and the building of a number of major bridges—for propaganda purposes. It wished to demonstrate the superiority of the National Socialist system over that of other world governments. However, while the Nazis used the Autobahn as a propaganda tool, the concept of the Autobahn did not originate under the Nazis, but rather in the 1920s during the Weimar Republic.

In 1926, the Planning Association for the Motorway Linking the Hanseatic Towns, Frankfort and Basle (HAFRABA) was created under the leadership of Willy Hof, a prominent German business leader. The HAFRABA was not a governmental body, but rather a private organization dedicated to advocating for the development of modern roadways. By 1926, motorized vehicles were becoming fairly commonplace among regular German citizens, and the HAFRABA wanted to promote the development of an infrastructure to allow motorized vehicles to easily and safely travel across the entire country, thereby connecting major cities and promoting commerce. To this end, the HAFRABA drew up construction plans for the roadway and began to lobby the Weimar Republic to finance the construction of this system of roadways (the Autobahn). The Weimar Republic rejected the project for two basic reasons. First, in order to build the Autobahn, the government needed to secure financing. Since bank credit was not readily available to the German government after the First World War, the only financing option would have been to charge tolls, as Italy did in building its national roadways in the 1920s. However, the assessment of tolls was a breach of German law and was therefore not an option (i.e. under the Financial Adjustment Law of 1926.) The second reason was that the German railroads lobbied against the development of any national roadway system, fearing that it would negatively impact their industry. Thus, it wasn’t until the Great Depression and the rise of the Nazi party to power that the idea of building the Autobahn was reconsidered. Hitler saw value in supporting the construction of the Autobahn for two reasons. First, it was a way to offer thousands of unemployed Germans employment, and second, it could be used as a propaganda tool to showcase the Nazi regime. Therefore, in 1933, Hitler met with Willy Hof to discuss the project. Hitler was able to use the brute force of his dictatorship to compel the railroads to withdraw their objection to the project. The project was financed by taxes on crude oil and petroleum, a levy on the railroads, loans from German banks, and by savings in unemployment compensation, due to increased construction industry employment. Contrary to popular belief, the Autobahn was not primarily built by slave labor. Up until 1939, when most able-bodied German men were conscripted into the military, free labor was used to build the Autobahn. It was only after 1939 that slave labor, made up of concentration camp prisoners and POWs, was used [1], [2].

Today, the building of the German Autobahn remains a highly charged subject, filled with negative political and historical implications. However, from a purely technical viewpoint, the Autobahn represents a significant engineering achievement. Despite its Nazi origins, the building of the Autobahn helped to lay the groundwork for post World War II German road-building technology and design expertise. Modern German highway engineers use advanced engineering techniques to extend the life of pavements, to reduce maintenance costs, and to minimize environmental impacts. Pavement design methods used in the German highway system are being studied in the United States today, in an effort to improve both general pavement performance and in order to make US roads more sustainable.

A Primer on Pavement Design:
Before beginning a discussion of sustainable pavement, we will cover, very broadly, the basics of pavement design, in order to become familiar with the types of pavement and their characteristics. This will allow an informed discussion of how sustainable pavement technologies can be best incorporated into US roads

Pavements can be placed in one of three categories: rigid pavement, flexible pavement, or composite pavement. Rigid pavement includes portland cement concrete pavements, with or without expansion joints and with or without steel reinforcement. Flexible pavement includes asphalt concrete pavement (more commonly known simply as asphalt pavement). Composite pavement consists of rigid (concrete) pavement underneath, covered with an overlay of asphalt. Each type of pavement has its unique advantages [3].

Rigid pavement is built of portland cement concrete, which is comprised of portland cement, fine and coarse aggregates, water, and various chemical additives to improve workability. Air is also sometimes entrained in the concrete to varying degrees, depending on the physical properties desired. In the case of reinforced concrete pavements, steel rebar is also used as part of the roadbed. The chemical reaction between the portland cement and the water drives a curing process that transforms the concrete mixture from a very viscous slurry into a solid with high compressive strength following a curing period. The fine and coarse aggregates used are traditionally various sizes of sand and gravel. However, increasingly, in an effort to reduce the environmental impacts of rigid pavements, various recycled materials are being substituted for sand and gravel as the aggregate. Such recycled materials include ground glass and ceramics, foundry ****, and crushed portland cement concrete, recovered from demolished roadways and construction projects and recycled back into the concrete mix as aggregate.[3] Fly ash from power plants has been used since the 1980′s to replace a portion of the portland cement component in concrete. (US EPA guidelines have mandated since the mid 1990s the use of fly ash in concrete.) The use of such recycled materials does more, from an environmental perspective, than merely keep these materials out of landfills. Viewed from a Life Cycle Assessment standpoint (discussed in greater detail below), using recycled materials in rigid pavements saves significant amounts of energy and raw materials and reduces the overall amount of green house gases generated over the lifecycle of the highway. This is primarily because virgin sand and gravel does not need to be mined and transported to the construction site. In the case of old highways being demolished and rebuilt, even greater environmental benefits can be achieved if the old concrete to be used as aggregate can be reground and reused on-site, thereby saving the energy that would have been expended to transport the recycled material to the road site.

Flexible pavement consists of asphalt cement, a mixture of asphalt ( a tar-like product derived from bituminous coal), fine and coarse aggregate, and various chemical fillers and additives to improve performance and workability. Asphalt paving operations are very energy intensive both because of the energy needed to mine the coal used to create the asphalt cement and because the asphalt has to be heated in order to liquefy it sufficiently to allow it to be mixed with the aggregate and laid down on the roadbed. Efforts to make flexible pavement more sustainable include 1) the use of recycled materials in place of the virgin aggregate, 2) the use of various recycled materials which contain asphalt ( such as roofing shingles) melted down and used in place of some of the virgin asphalt cement, and 3) the use of various additives to increase the workability of the asphalt cement at low temperatures, thereby reducing energy demands associated with mixing and laying down the pavement.

Composite pavement consists of a bed of rigid pavement overlaid with asphalt concrete. It combines the environmental impacts of both rigid and flexible pavements. Its primary advantage over either of the other two types is improved ride-ability and noise reduction characteristics [3].

Regardless of the pavement type, the key to optimal durability and performance is a well-prepared road bed, including a properly designed drainage system and a properly designed and compacted sub-base (usually comprised of various grades of dirt, sand, and gravel).

Decisions on which pavement type to use have been driven by cost, and have differed based on location and societal viewpoints. In the US, first-cost considerations have often dominated road building decisions. Many US governmental bodies (federal, state, local) seem willing to tolerate more on-going maintenance costs in favor of lower first costs. This philosophy has favored the use of flexible and composite pavements in many (although not all) areas of the US. However, in Europe (in Germany and Austria in particular), the philosophy favors building roads that are extremely durable, which have low maintenance requirements, and which have very long life spans. This philosophy tends to favor rigid pavement designs, which can have significantly higher first costs, but lower maintenance costs. The Autobahn itself is an example of this.

While cost has historically been the main driver in pavement design, sustainability is now an additional design parameter considered by highway engineers. Because of the German emphasis on rigid pavement design, much of the research on how to make rigid pavements more sustainable has come out of Germany. It is based on the premise that by increasing life span and minimizing maintenance requirements, one inherently lowers environmental impacts because over the life span of the road, fewer interventions involving the expenditure of energy and raw materials are needed. Because of the greater emphasis on flexible pavements in much of the US, US engineers have emphasized the recycling of materials and various energy conservation strategies more in their quest to develop more sustainable pavements. Part of this emphasis is driven by governmental mandate. (The US federal government passed the Intermodal Surface Transportation Efficiency Act (STEA) in 1994, which mandated the use of recycled tire content in asphalt paving projects which receive federal funding.) Both approaches have validity, but ultimately, neither provides the full picture on how to maximize pavement sustainability. The big picture can only be understood in the context of a Life Cycle Assessment, discussed below

Life Cycle Assessment and the Attributes of Sustainable Pavement:
In trying to determine which of the pavement types (rigid or flexible) is more sustainable, and in trying to develop new strategies for minimizing the environmental impacts of roads and pavement, a life cycle assessment must be conducted. Life Cycle Assessment (LCA) is a technique which views the entire life cycle of an engineered system as a single control volume. It looks at energy and mass inputs and outputs from the control volume and quantifies the environmental impacts based on how much energy and resources are used to create the system and on how much hazardous waste and green house gases are generated. It must include impacts ranging from the energy required to extract and transport the raw materials during initial construction, to the impacts which occur during routine system maintenance, to the impacts created during final disposal of residues and wastes from the system following demolition. Researchers have created databases and software packages which help to catalog and calculate environmental impacts.

One of the most comprehensive LCA databases is the US Department of Energy’s LCI Database, available on-line [4]. The DOE LCA database quantifies the environmental impacts of a number of basic industrial and construction processes in terms of the amount of energy they consume and the amount of greenhouse gases and toxic emissions produced. Using DOE LCI, one can find the energy cost and emissions for the production of unit quantities of portland cement, asphalt, steel, and other raw materials used in pavements. Using this data along with estimates of the energy and emissions costs to transport and install them, researchers are able to quantify the relative sustainability of different pavement types and systems.

Horvath and Hendrickson [5] conducted an LCA comparing asphalt pavement to steel reinforced concrete pavements (RCP). The LCA considered energy consumption, ore and fertilizer requirements, toxic emissions, and the hazardous wastes generated during extraction, transportation, mixing, and construction of both asphalt and RCP pavements. Their study initially assumed no recycled content in either type of pavement; the analysis was based upon the use of virgin raw materials. Their conclusions were that RCP required less energy and generated lower amounts of hazardous wastes, but had higher ore and fertilizer requirements and higher toxic emissions, than did asphalt pavements. But, if one subsequently accounted for the fact that there is currently more recycled content in asphalt pavement than in RCP, asphalt pavements can be concluded to be marginally more sustainable.

The results of this study can be understood best if one understands the primary environmental impacts for both RCP and asphalt pavements. Portland cement production is extremely energy intensive and the production of the portland cement used in RCP pavement production is arguably the single largest negative environmental impact associated with rigid pavements. The largest negative environmental impacts in the production of flexible (asphalt pavements) are the large amounts of energy needed to mine the bituminous coal from which the asphalt is produced, and the energy required to warm the asphalt mix prior to installation. To the extent that a portion of virgin asphalt is being successfully replaced with recycled asphalt shingles, with recycled tires, and with recycled asphalt cement pavement re-melt, total energy costs to produce flexible pavements can be driven down. Since the portland cement component in concrete is chemically changed during the concrete curing process, a similar opportunity to recycle this component of RCP, and thus save energy is not possible. Hence, other strategies, mainly aimed at extending the life of concrete pavements, must be employed to make rigid pavement design more sustainable.

Recent Developments to Enhance the Sustainability of Pavements:
Keeping in mind the principles of LCA and the attributes of sustainable pavements discussed above, a number of interesting avenues to minimize the environmental impacts of both rigid and flexible pavements are being researched.

In the category of rigid pavement, German engineers continue to lead the quest to reduce the environmental impacts of portland cement concrete pavements.

One of the major directions this research is taking is in the development of two-layer concrete pavements. These pavements consist of two separate PCC layers—a thick sub-layer, covered with a relatively thin wear layer. Such pavements have been shown to have durability that is comparable to traditional single layer PCC pavement, yet because they are comprised of two layers, it is possible to more readily use higher amounts of recycled materials in the aggregate of the sub-layer. Lower quality aggregate—such as recycled, ground PCC pavement, ground glass, and **** are used in the sub-layer. These recycled aggregates do not appear to reduce the structural performance of the pavement. A higher quality, more expensive aggregate, such as pea gravel, is reserved for the wear layer. This aggregate is exposed as part of the surface finishing process during construction. The exposed aggregate improves roadway safety (by improving pavement friction characteristics) and reduces road noise characteristics. In addition to reducing environmental impacts, and improving friction and noise characteristics, the two-layer PCC pavement is also cheaper [6]. Another German innovation in two-layer PCC pavement is the use of a 3 millimeter thick, polymeric geotextile as an interlayer between the two PCC layers [7[. This interlayer has been shown to lengthen the life of the pavement through 3 mechanisms: 1) the interlayer keeps cracks and other discontinuities in the lower layer from propagating to the wear layer; 2) the interlayer, if properly installed, can promote drainage of any water that enters the wear layer away from the bottom structural layer, thereby increasing roadbed life by reducing cracking due to freeze-thaw cycles; and 3) the interlayer absorbs some of the dynamic stresses caused by heavy traffic, thereby reducing stresses on the structural sub-layer and thus extending its life. The primary disadvantages of the use of the geotextile are its added cost and the need for careful installation to ensure proper performance. This necessitates having a highly proficient and well-trained construction team.

Another German road design practice that is making its way into the US is a movement away from steel reinforced concrete to plain concrete pavements. In a seminal, 15 year longitudinal study in Michigan, comparing standard US concrete pavement design (the control) to standard German concrete pavement design along a stretch of Michigan highway near Detroit, one conclusion has been that steel reinforcements can actually promote transverse cracking in the pavement, thereby shortening its life [8]. Since eliminating steel from PCC pavement removes one material input to the LCA, while potentially also lengthening its overall life and reducing maintenance costs, this change can make PCC pavements more sustainable as well.

Finally, another growing trend to improve the sustainability of PCC pavement has been to use scrap tires to fuel portland cement kilns instead of coal. Since the production of portland cement remains highly energy intensive, one way of mitigating the environmental impacts across the life cycle of the pavement is to recover the embodied energy in scrap tires, rather than use “virgin” coal to fuel the kilns. Not only is this more sustainable, but it saves energy costs during production. In 1996, 23 cement plants across the US used tires as a supplemental fuel. Air emissions using scrap tires as fuel are no worse than air emissions from burning coal. And, given that 250 million tires are discarded in the US per year, which possess 15,000 BTU per pound, this represents a potentially significant energy and material savings [9].

Recent developments to improve the sustainability of flexible pavement (in addition to the increasing reuse of asphalt concrete as re-melt, and the use of used asphalt shingles, both discussed above) include Cold-in-Place recycling (CIR) and Cold-in-Place recycled expanded asphalt mix (CREAM) [10]. Both of these technologies involve the on-site reclamation of used asphalt pavement using specialized machinery that can demolish the existing pavement, regrind it on-site, re-melt it and lay it down to create a new pavement surface. CIR uses various chemical additives and conditioners to allow the recycled pavement to be melted and reworked at lower temperatures than normal, thus saving energy. CREAM uses a similar technology, but also adds air to create an asphalt foam, that can be reworked at lower temperatures. The combination of on-site reclamation (thereby removing transportation impacts from the LCA and reducing the impacts associated with the use of virgin asphalt cement) with the reduced energy costs of re-melting and remixing the asphalt places both CIR and CREAM at the forefront of sustainable technologies for flexible pavements.

Final Thoughts:
Increased mass transportation and the development of vehicles that minimize the use of fossil fuels are the ideas that have often dominated our national discussion of ways to make our transportation system more sustainable. Indeed, both are important strategies in the overall effort to reduce the environmental impacts of transportation. But, the use of the personal automobile is not likely to vanish any time soon. And, our economy relies on semi tractor-trailers to haul large amounts of freight. Given these facts, the need for well-constructed highways will continue into the foreseeable future. However, as this essay is intended to show, the existence of our national highway system can be compatible with responsible environmental stewardship. Highway engineers have made considerable progress through innovative designs and increased recycling to reduce the environmental impacts of highway construction and maintenance. And, just around the “bend in the road,” there will undoubtedly be even more interesting and exciting developments in sustainable pavements in the future.

References:

  1. “The Autobahn Myth”; Oster, Uwe; History Today , November, 1996, p. 39- 41. (Translated from German by Judith Hayward).
  2. “The Third Reich’s Concrete Legacy”; Boser, Ulrich; U.S. News and World Report, Volume 134, Issue 23, p. 45, June 30, 2003.
  3. The Highway Engineering Handbook—Building and Rehabilitating the Infrastructure, 3rd Edition; Roger L. Brockenborough, P.E., editor; 2009; ISBN: 978-0-07-159763-0.
  4. DOE LCI Database, https://www.lcacommons.gov/nrel/search.
  5. “Comparison of Environmental Implications of Asphalt and Steel-Reinforced Concrete Pavements”; Horvath, A. and Hendrickson, C., Transportation Research Record: Journal of the Transportation Research Board of the National Academies; Volume 1626, 1998.
  6. “Design and Construction of Sustainable Pavements: Austrian and German Two-Layer Concrete Pavements”; Tompkins, D., Khazanovich, L., Darter, M., and Fleischer, W.; Transportation Research Record; Volume 2098, p. 75-85, 2009.
  7. “Nonwoven Geotextile Interlayers for Separating Cementitious Pavement Layers: German Practice and U.S. Field Trials”; Rasmussen, R. and Garber, S.; Research Report prepared by the International Scanning Study Team for the Federal Highway Administration, U.S Department of Transportation, May 2009.
  8. Fifteen Year Performance Review of Michigan’s European Concrete Pavement, Smiley, D., Report Number R-1538, Michigan Department of Transportation, Construction and Technology Division, February, 2010.
  9. A Comparison of Six Environmental Impacts of Portland Cement Concrete and Asphalt Cement Concrete Pavements; Gadja, J., and VanGeem, M., PCA R&D Serial No. 2068, Portland Concrete Association, 2001.
  10. “Sustainable Pavements: Environmental, Economic, and Social Benefits of In-Situ Pavement Recycling”; Alkins, A., Lane, B., and Kazmierowski, T.; Transportation Research Record: Journal of the Transportation Research Board of the National Academies, Volume 2084, 2008.

child_labor_in_the_dye_works.jpg

By Deborah Jackman, PhD, PE, LEED AP™ - originally posted on 04/11/2012

The Painting:
‘Child Labor in the Dye Works’ is attributed to the German artist, Heinrich Kley, who lived between 1863 and 1945.  The exact date of the painting is unknown, but based upon the style of dress of the workers and the equipment used, the painting was likely created sometime between the mid 1890s and the start of the World War I (1914).  It depicts an industrial yarn dyeing operation, presumably in Germany.  The portion of the scene that draws the eye is the brilliantly colored yellow yarn being transferred from the dyeing process by the child worker.  The use of child labor is, of course, forbidden in developed countries today, but persists– contrary to international pressures to curtail it– in some developing nations. However, the primary purpose of this article is not to discuss child labor in the developing world. Instead, we will use the image presented in the painting as a springboard to explore the broader environmental implications of textile dyeing operations. Before discussing these environmental impacts and what can be done to minimize them, it is helpful to understand in overview the history of textile dyeing.

A Brief History of Textile Dyeing:
Dyeing of fibers to produce colored cloth is among the oldest of human activities.  Until the first aniline dye, mauve, was synthesized by William Henry Perkins in 1858, all dyes were natural in origin—derived either from plant, animal, or mineral sources.  The initial driving force behind the development of synthetic dyes was the desire to have a wider variety of more vibrant colors available than were obtainable from natural sources.  Then, once synthetic fibers such as nylon began to be introduced in the mid 1940’s, a secondary driver for the continued use of aniline dyes was the fact that synthetic fibers took up synthetic dyes more readily than natural dyes. Following the introduction of synthetic mauve dye, other aniline dye colors were gradually introduced such that by 1900 a full range of colors were available in the form of synthetic aniline dyes [1].  Aniline dyeing of wool had the additional advantage of not requiring a mordanting step, as the use of natural dyes did.  (Mordanting is a chemical pre-treatment of the fiber separate from the dyeing step itself required to ensure that the pigment takes to the fiber and remains color-fast.)  The upshot of all of these factors is that by the mid 20th century, aniline dyes ( and their close chemical derivatives—azo dyes) had supplanted natural dyes in nearly all commercial textile operations world-wide.

The timeline of the technical development of aniline dyes discussed above might suggest that the colored fibers depicted in our painting were the product of aniline yellow, but this is likely not the case.  Rather, the yellow yarn depicted in the painting is likely wool dyed with weld—a natural dye derived from the weld plant (Reseda luteola) [2].  The reasons for this are economic, not technical.  Even though the technology for using aniline dyes was probably known at the time this painting was created (estimated to be the mid 1890s to 1914), the wool textile industry in Germany was depressed until 1904 due to high tariffs imposed by countries to which Germany would have exported its colored fibers.  Thus, textile manufacturers did not invest significant money into updating operations until after at least 1904 because there was little economic incentive for them to do so [3].  To further the irony, during the late 19th century Germany was the center of R&D work on organic chemical synthesis, and German companies held most of the chemical patents for synthetic dyes.  In 1913, 80% of the synthetic dyes exported to the rest of Europe and to America came from Germany and yet, German textile manufacturers lagged behind other nations in adopting the synthetic dyes in their own operations.  During World War I many German chemical plants were destroyed for fear that they were manufacturing mustard gases and other chemical warfare agents, and after the War, many of these German dye patents were seized.  The nexus of synthetic textile dye manufacturing then shifted to the U.S. [4].

Environmental Impacts of Textile Dyeing:
The use of weld to dye wool and other natural fibers, as depicted in the painting, has relatively low environmental impacts compared to synthetic dye operations, but is not totally benign.  The spun fibers or woven, un-dyed cloth is placed in hot (200 F) water to which enough alum (sodium aluminum sulfate, NaAl(SO4)2 ,) has been added to create a 1:4 alum to fiber (by weight) solution.  The fibers are steeped in the hot solution for 12 hours.  This is the mordanting step which prepares the fibers to accept the dye.  Once mordanted, the fibers are transferred to another vat containing a hot (150F to 200F) aqueous weld dye solution.  They are kept in the dye solution until the desired shade of yellow is obtained.  The fibers are then removed, washed with a pH neutral soap and allowed to dry.  The aqueous weld dye solution is prepared by crushing the stems, leaves, and flowers of the weld plant and placing them in a vat covered by water.  The mixture is brought to the boiling point and allowed to steep for 30 minutes.  The colored solution is then strained to remove the solids [5].  Given that both the weld plant and the alum have low toxicity, they do not present a hazard from a material or human health/worker standpoint.  But because of the extreme color intensity of the aqueous dye solution, it does need to be decolorized before being discharged as an industrial wastewater in a manufacturing setting.  Such decolorization can be accomplished by processing the solution through an activated carbon filter or by using ultrafiltration or ion exchange technologies. From a more generalized sustainability standpoint, the weld dyeing process is quite energy intensive (due to the need to heat the solutions and to maintain their temperature for relatively long periods), and is also water intensive (although a given batch of weld dye can be reused to do multiple batches of fibers by re-fortifying the dye bath with more weld).    Although we are focusing on the use of weld dye to produce yellow fibers in reference to our subject painting, other natural dyes used to produce other colors generally exhibit similar environmental impacts to that of weld.

Aniline yellow and other aniline and azoic synthetic dyes exhibit more severe environmental impacts than natural dyes.  Most synthetic dyes are delivered to textiles by creating an aqueous (i.e. water based) dye solution, immersing the fibers in the dye solution at elevated temperatures  (100 to 130 C) for a specified period, and then removing the fibers or woven cloth for further finishing, including drying.  Most synthetic dyes, including aniline and azoic dyes, do not require a mordanting step, which is one of the distinct advantages of synthetic dyes.  Various pieces of specialized machinery have been developed by the modern textile industry to optimize and mechanize such dying operations.    Reference [6] provides a detailed technical review of various modern textile dyeing processes and related equipment.  However, regardless of the specifics of a particular technique, the general process involves the use of considerable amounts of energy and water, just as the natural dyeing process does.  In this regard, there is little difference in the environmental impacts or sustainability of the use of natural versus synthetic dyes.

The differential environmental impacts between natural dyes and synthetic aniline/azo dyes occur at two other points in the life cycle of the dye–  its manufacture and the disposal of resulting dye wastewaters.  At both of these points in the life cycle, aniline/azo-based dyes have much more negative and severe impacts than do natural dyes.

The manufacture of azoic dyes involves a complex, multi-step process of organic chemical synthesis. The root source of the chemicals used to synthesize azoic dyes is petroleum (i.e. crude oil). The precursor chemical to Yellow Azo dye (and other shades of azo dyes) is aniline which is converted into the dye via an oxidation process.  Aniline, itself, is an aromatic (i.e. based upon the benzene ring structure) amine.  It is acutely toxic to humans and also likely carcinogenic although evidence of its carcinogenicity is somewhat contradictory. Various azo dyes have been banned by the European Union due to concerns about their carcinogenicity [7],[8],[9].  Each step in the chemical synthesis of azo dyes from the extraction of the crude oil to the final synthesis from aniline has significant negative environmental impacts.

Large scale agricultural production of weld and other dye plants would also use petroleum to fuel farm machinery and to transport the harvested plants, but since there are not as many steps and chemical reaction processes between the planting of the weld and its final use, and because the intermediaries in the processes do not involve the use of aromatic chemicals such as aniline and benzene, the production of natural dyes is arguably far more sustainable than the production of synthetic dyes.  The weld plant itself is a hardy perennial, native to temperate regions of Eurasia.  It is drought tolerant, thrives in poor soils, and is not subject to insect infestations.  Therefore, cultivation of weld for use in dyes is relatively low impact, not requiring significant amounts of fertilizers or pesticides.

Once synthetic dyes are spent, the steps involved in treating the resulting dye-laden wastewaters are expensive and complex. Singh and Arora [10] provide a critical review of present treatment technologies being employed to treat wastewaters containing azo dyes.  A variety of physical, chemical, and biological treatment strategies are being employed singly and in combination to remove azo dyes prior to discharge of these industrial wastewaters.  Because azo dyes can be degraded biologically in the natural environment to produce by-products such as aniline and related toxic aromatic chemicals, it is necessary to remove these dyes prior to discharge.    Treatment strategies such as carbon adsorption; coagulation, flocculation and settling; filtration; membrane processes; ion exchange; direct chemical oxidation; UV irradiation; and aerobic and anaerobic biological treatments are being used to capture or destroy the azo dye chemicals before they reach the environment.  In those cases where the azo chemical is merely transferred to another medium rather than destroyed (e.g. coagulation/flocculation/filtration), the environmental hazard is not eliminated but must still be dealt with through yet another series of steps such as incineration or land filling.  In contrast, wastewaters containing natural dyestuffs or alum mordanting solutions do not require as extreme of treatment steps—simple decolorization using carbon adsorption or via UV irradiation is typically sufficient because the dyes are not toxic.  Treatment is done simply to meet water standards related to color and turbidity.  Again, in terms of what is required to treat the wastes generated in textile dyeing operations, natural dyes exhibit far more sustainability.  Potential pollution is prevented rather than having to be remediated.

Future Developments to Promote Sustainability:
As we have discussed, both natural and synthetic textile dyeing operations have adverse environmental impacts; although arguably, those involving natural dyestuffs have fewer impacts. Nevertheless, because even natural dyeing operations use large amounts of energy and water, the textile industry continues to seek even more sustainable methods to color fibers.

Thiry, [11], discusses several new and more sustainable strategies for coloring fibers and fabrics that are likely to replace, at least in part, traditional solution-based dyeing operations in the near future.  Among the new strategies being developed are 1) ultra low liquor ratio dyeing; 2) selective plant breeding to produce naturally colored cotton fibers; 3) digital printing of fabrics; 4) cationic cotton printing; and 5) waterless dyeing involving the use of supercritical CO2.  Ultra low liquor ratio dyeing reduces both water and energy usage by reducing the weight ratio of the dye solution to the fabric to levels as low as 3:1 for some fabrics.  The smaller the amount of water used, the less energy is required to heat the solution and the smaller the amount of wastewater ultimately generated.  Cotton is the most commonly used natural fiber in the world, largely because of its use in denim fabrics.  Prior to relatively recent attempts to breed color out of cotton in order to produce higher agricultural yields, cotton grew with various naturally occurring pigmentations such as red, green, and brown.  Recently, growers are working to breed these natural color variations back into cotton, producing fibers requiring no dyeing whatsoever.  Digital printing of fabrics using technologies similar to the ink jet printing used with paper use no water whatsoever.  However, the production of the ink jet cartridges and the chemicals contained in them involve certain environmental impacts. (As with any discussion of sustainability, one must consider not just the impacts of the immediate process, but of the entire life cycle associated with that process.)  Cationic cotton printing involves treating cotton fabric so that it has a positive (cationic) charge.  The charged cotton is then immersed in a dye bath containing a reactive dye that attaches itself to the charged sites on the fabric.  Using the correct chemical ratio of dye to fabric results in water in the dye bath which is free from all chemicals and color at the end of the batch process.  That water can then be reused in dyeing subsequent batches of fabric, thereby conserving water.  Cationic dyeing is conducted at room temperature, meaning it is less energy intensive than traditional chemical dyeing operations.  Details on the production of these cationic dyes were unavailable and so we cannot draw a conclusion of their broader sustainability over the entire life cycle of the process.  Finally, some textile manufacturers are attempting to develop a dye process using supercritical CO2 .The carbon dioxide is exposed to extremely high pressures at relatively low temperatures (room temperature and below).  As any student of basic thermodynamics knows, this will cause the CO2 to exist in the liquid state.  The pigments are suspended in the liquid CO2 and the fabric is introduced.  Then the pressure of the system is dropped and the CO2 evaporates, leaving a completely dry dyed fabric.  While technically feasible, it has not been scaled up for full scale production because it is not economically competitive with conventional dyeing processes at this time.

In addition to the various innovative strategies discussed above, the textile industry is also experiencing a resurgence in interest in the use of natural dyes and associated processes, as a way to mitigate environmental impacts.  Allegro Natural Dyes, a company located in Longmont, Colorado, was an industry start-up in 1995, created with the intent to re-introduce natural dyes into the textile industry, [12].  The company has subsequently obtained a number of patents involving various proprietary processes centered around the production of natural dyes.  Allegro is an interesting case because it supports the premise that the use of natural dyes can be economically competitive to synthetic dye-based practices in today’s modern textile industry.  Hence, in some ways, the textile industry has come full circle.

Today there clearly exists an opportunity to employ the best parts of both traditional and modern dyeing practices to produce a more sustainable textile industry overall.  The use of natural dyes combined with modern water treatment technologies such as ion exchange and membrane technologies, and combined with various energy recovery techniques, could produce industry processes that would capitalize on the low environmental impacts of natural dye production and yet could mitigate the water and energy intensiveness of the dyeing process.  This would result in a sustainable process over the life cycle of the dyeing operation.  It represents an exciting modern sharing of new technology with age-old traditional practices.

References:

  1. The Cambridge History of Western Textiles, Jenkins, David, editor, Cambridge University Press, 2003, p.764.
  2. New International Encyclopedia, “Weld”, Gilman, Daniel Coit; Peck, Harry Thurston; Colby, Frank Moore; Dodd, Mead & Company, New York, 1905.  [Wikisource].
  3. Jenkins, op. cit., p. 782.
  4. Jenkins, op. cit., p.1082-1084.
  5. The Art and Craft of Natural Dyeing: Traditional Recipes for Modern Use, Liles, J.N., Knoxville: University of Tennessee Press, 1990.
  6. “ A Review of Textile Dyeing Processes”, Perkins, Warren, S., Textile Chemist and Colorist, Vol.23, No.9, August, 1991.
  7. “Aniline”,  http://en.wikipedia.org/wiki/Aniline , January 21, 2012.
  8. “Azo compound”, http://en.wikipedia.org/wiki/Azo_dye , February 16, 2012.
  9. Environmental Impact of Textiles; Slater, Keith; Woodhead Publishing, LTD.; 2003, p. 81-82.
  10. “Removal of Synthetic Textile Dyes From Wastewaters:  A Critical Review on Present Treatment Technologies”; Singh, K., and Arora, S.; Critical Reviews in Environmental Science and Technology, 41: 807-878, 2011.
  11. “Color it Greener”; Thiry, Maria, C.; AATCC Review, Vol. 10, Issue 3, p.32-39,      2010.
  12. “Natural Dye Startup”; Chemical Week; Vol.157, Issue 7, 0009272X. August 23, 1995.

By Deborah Jackman, PhD, PE, LEED AP™ - originally posted on 03/23/2012

This article represents the first installment of what will be a series of technical essays on trends in sustainability which are occurring across a wide spectrum of businesses and industries.  As a springboard for discussion, and in order to provide historical context, each article will feature one or more paintings from the Man at Work Collection.

The Man at Work Collection held at the Grohmann Museum, located at the Milwaukee School of Engineering (MSOE), provides a detailed visual record of how technology has evolved since the 16th century.  With the current emphasis on increasing the sustainability of 21st century manufacturing, agriculture, transportation, and construction, and on reducing the carbon footprint of human activities globally, it is instructive and informative to study the technological practices of previous generations.  An understanding of how past generations used technology can be used as a springboard for analyzing and discussing how we can make our 21st century technologies more sustainable.

Each article will focus on one painting from the Man at Work Collection. The painting will be used as a starting point for discussing production practices within the featured industry.  In some cases, the historical practices revealed by the paintings will suggest ways that we can make our modern practices more environmentally sound, i.e., ways we can learn from the past to ensure a more sustainable future. In other cases, they may provide lessons in what should be avoided. In any case, the painting will provide a rich forum for discussing some aspect of sustainability within targeted industries.  The selection of paintings and the industries represented in those paintings will be somewhat random and will be based on my personal areas of technical interest. During the course of the series, we will cover an eclectic mix of industries and subject matter. 

What constitutes a sustainable practice must be defined in order to focus the discussion.  While there are many definitions of sustainability, all are based on certain common underlying principles.  These principles seek to maximize performance in five key areas:  (1) energy efficiency; (2) water conservation and reuse strategies; (3) materials and resources efficiency; (4) environmental health and safety for workers/inhabitants; and (5) site/activity location selection to mitigate potential ecological impacts.  At least one of these criteria will be examined and discussed in each of the paintings studied.

Each painting presents an image that is complex—one that can be taken in any number of directions relative to the sustainability issues discussed.  These essays are not intended to be exhaustive in their discussions of all aspects of sustainability within a given industry.  Instead, references will be provided so that the reader can delve more deeply into those areas that interest him.  I hope that this series of essays will be as interesting and informative for you, the reader, as they promise to be for me in researching and presenting them to you.  Articles will be published approximately every three months.  I welcome your comments.