12 principles examples

Anastas/Zimmerman Supporting Information for ES&T A-page feature

“Design Through the 12 Principles of Green Engineering” (March 1, 2003)

Principle 1: Designers need to strive to ensure that all material and energy inputs and outputs are as inherently nonhazardous as possible.

Principle 2: Preventing waste is better than treating or cleaning it up after it is

formed.

At every design scale, an opportunity exists to prevent waste rather than treat it after it is

generated. Waste requires the expenditure of capital, energy, and resources with no

realized benefit. Examples are presented in Table 1 for molecules, processes, products,

and systems to demonstrate moving from the status quo toward sustainable design

through the application of Principle 2.

TABLE 1

Examples of status quo and application of Principle 2 across design scales

Design scale Current practice Application of principle

Molecular Protecting groups;substitution reactions

Atom economy (1)

Process Dry cleaning with perchloroethylene

Dry cleaning with supercritical CO2

Product Virgin paper Paper with recycled content

System Fossil energy Fusion energy

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Principle 3: Separation and purification operations should be a component of the design framework.

Separation and purification operations can be designed at every scale to minimize energy

consumption and materials. This design strategy can be used at the beginning of the

product’s life to isolate the desired output or at end of life to aid in the recovery, reuse,

and recovery of materials as illustrated by the examples in Table 2.

TABLE 2



Molecular Column chromatography; distillation

Reaction product insoluble in reaction medium (2)

Process Permanent joining/bonding of two materials Reversible fastening

ProductCircuit board masks and etching using large volumes of organic

solvent

Computer chip manufactured by vapor deposition

System Separation intensive recycling of municipal waste

Local/residential material and energy systems

Principle 4: System components should be designed to maximize mass, energy, and temporal efficiency.

Processes and systems often use more time, space, energy, and material than are

necessary. Table 3 illustrates examples where designing for maximized efficiency and

intensity moves toward eliminating the design flaw of waste.

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TABLE 3



Molecular Batch reactors using large volumes of solvent

Continuous flow microreactors (3); spinning disk reactors

Process Painting Powder coating

Product Printed media Digital media

System Urban sprawl Ecoindustrial park planning

Principle 5: System components should be “output-pulled” rather than “input-pushed” through the use of energy and materials.

Extensive energy and material inputs often drive a transformation toward the desired

outcome. This logic has resulted in waste, inefficiency, and environmental damage. Table

4 presents examples at each scale in which the final outcome is “pulled” rather than

“pushed”. This concept can be applied to all design scales minimizing the demand for

resources to obtain the desired output and resulting in a more sustainable design.

TABLE 4



Molecular Excess reagent Dehydration reactions

Process Coating technologies with high curing temperature Fermentation product removal

Product Metal casting Direct metal deposition (4)

System Marketing overproduced items at a minimal profit “Just in time” manufacturing

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Principle 6: Embedded entropy and complexity must be viewed as an investment when making design choices on recycle, reuse, or beneficial disposition.

The degree of complexity is a function of the expenditure of materials, energy, time, and

capital. These investments should be considered when making design choices on recycle,

reuse, or beneficial disposition. High complexity should generally correspond to reuse,

while lower complexity should correlate with recycling where possible and beneficial

disposition where necessary. Table 5 provides examples of applying Principle 6 at each

design scale and has led to more sustainable design decisions.

TABLE 5


Design scale Complexity Current practice Application of principle

MolecularLow “Flaring” methane at petroleum

refineries

C-1 (carbon) as a feedstock for value

added material

High Complex biomaterials reduced to hydrocarbon feedstocks

Chiral molecules with multiple stereo centers

ProcessLow

Incorporating used rubberas a fill material for its

bulk properties

Depolymerization of homopolymers

High Incineration of PET bottles Regeneration of Petretec polymer (5)

ProductLow Landfilling of yard “waste” Using yard “waste” for

mulch

High Single-use(nonrechargeable) batteries

Refurbished/re-manufactured copiers

System

Low Municipal wastewater treatment sludge to landfill

Sludge for energy and/or agricultural

High Under-used public school buildings torn down

Former schools converted to senior

centers

Principle 7: Targeted durability, not immortality, should be a design goal.

Persistence of synthetic materials in the environment and biosphere is increasingly

recognized as incompatible with sustainability, and some of these examples are listed in

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Table 6. The targeted durability of product, process, and system levels can help avoid the

legacy of environmental impacts that have historically caused extensive concerns.

TABLE 6



Molecular Polyacrylic acid Polylactic acid (6)

Process Paper coating with petroleum-based polymers

Paper coating with renewable, biodegradable polymers

Product Polystyrene packaging material Eco-fill (7)(starch-based packing peanut)

System Utility energy sales Energy efficiency buy-back programs

Principle 8: Design for unnecessary capacity or capability should be considered a design flaw. This includes engineering “one-size-fits-all” solutions.

Table 7 provides examples of where historical “overengineering” in unsustainable ways

has caused environmental concerns and where the application of Principle 8 has and can

result in more sustainable products, processes, and systems.

TABLE 7



Molecular Excessively reactive reagents Enzyme catalysts under mild conditions

ProcessOverchlorinating or

overdisinfecting domestic drinking water

Real-time process analysis/controlled systems (8)

Product “Off-the -shelf” technologies Technologies specific to needs and demands of end user

System Shipping by underutilized fixed capacity vehicles

Shipping by rail with railcars that can attach or detach as

needed

5

Principle 9: Multicomponent products must minimize material diversity and strive for using materials that promote disassembly and value retention.

In certain design fields and engineering specialties, up-front design will determine to

what degree a product can be disassembled and the value recovered. The application of

Principle 9 to the examples in Table 8 illustrate how movement from the status quo to

next-generation design can be accomplished across scales.

TABLE 8



Molecular Multistep syntheses One-pot reactions, cascading reactions, self-assembly (9)

Process Plastics with dyes, Plasticizers and elasticizers

Properties of polymers built into the backbone (10)

Product Vehicle door panel based on multiple plastic types

Vehicle door panel based on monomaterial (i.e.,

polypropylene) synthesized to meet mechanical property

demands

System Analog photography developing Digital photography developing

Principle 10: Design of processes and systems must include integration of interconnectivity with available energy and materials flows.

While the list of examples in Table 9 shows the importance of interconnectivity of

material and energy flows in moving toward sustainability from the current status quo,

there are important caveats. Design for interconnectivity requires that the designer

recognize that such integrated systems can be either very stable or very vulnerable to

isolated failure causing cascading impacts. The positive impacts of integrating flows on

sustainability are an essential design element.

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TABLE 9



Molecular Neutralizing waste acids to waste salts

Using “waste” nitrous oxide as in-process oxidant (11)

Process Flaring at refineries Cogeneration of energy

ProductBraking systems integrated with

drive trains based on internal combustion engines

Regenerative braking in hybrid electric cars (12)

System Municipal solid waste/landfill Kalundborg, Denmark

Principle 11: Performance metrics include designing for performance in commercial “afterlife”.

Table 10 features examples of how Principle 11 can be used to design products,

processes, and systems for commercial afterlife, ensuring that the impacts are nonharmful

if not beneficial. With forethought, design can ensure performance and value long after

initial commercialization.

TABLE 10



Molecular Polyester fabrics Nylon 66

Process Single-purpose unit process Flexible manufacturing

ProductPersonal electronics (cellular

phones, PDAs, laptop computers)

Xerox copiers (13)

System Single-purpose/use buildingsConvert industrial buildings

to housing at end of business life

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Principle 12: Material and energy inputs should be renewable and from readily available sources throughout all life-cycle stages.

Table 11 illustrates how applying Principle 12 to current practices can help move toward

sustainability and ensuring material and energy inputs are renewable rather than

depleting, where technically and economically feasible. While moving toward renewable

material and energy sources will require extensive innovation and infrastructure,

examples already exist where these types of technologies have been successfully

commercialized.

TABLE 11



Molecular Petroleum-based feedstocks Recovered biomass feedstock

Process Wastewater/water treatment by chemically based systems

Wastewater/water treatment by natural ecosystems (14)

Product Petroleum-based plastics Bio-based plastics

System Hazardous waste site soil extraction/cleaning Phytoremediation

References

(1) Trost, B. Science 1991, 254, 1471–1477.

(2) Bergbreiter, D. E. J. Polym. Sci., Polym. Chem. Ed. 2001, 39, 2352.

(3) Hendershot, D. Chem. Eng. Prog. 2000, 96, 35–40.

(4) Mazumder, J.; Schifferer, A.; Choi, J. Mater. Res. Innov.

1999, 3, 118–131.

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(5) U.S. EPA Presidential Green Chemistry Challenge;

www.epa.gov/greenchemistry/docs/award_recipients_1996_2002.pdf

(6) Green, C. AURI Agric. Innov. News 1999, 8, 4.

(7) Drumright, R. E.; Gruber, P. R.; Henton, D. E. Adv. Mater. 2000, 12, 1841–1846.

(8) Illman, D. L.; Callis, J. B.; Kowalski, B. R. Am. Lab. 1986, 12, 8–10.

(9) Whitesides, G. M. MRS Bull. 2002, 27, 56–65.

(10) Matyjaszewski, K. Macromol. Symp. 2000, 152, 29–42.

(11) Draths, K. M.; Frost, J. W. J. Am. Chem. Soc. 1994, 116, 399–400.

(12) Lovins, A. Hypercars: The Next Industrial Revolution. In Proceedings from

IEEE Aerospace Applications Conference, Snowmass, CO, 1996.

(13) Smith, H. Ind. Environ. 1997, 20, 54–56.

(14) Riggle, D; Gray, K. BioCycle 1999, 40, 40–41.

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