Green engineering

Green engineering approaches the design of products and processes by applying financially and technologically feasible processes and products in a manner that simultaneously decreases the amount of pollution that is generated by a source, minimizes exposures to potential hazards (including reducing toxicity and improved uses of matter and energy throughout the life cycle of the product and processes) as well as protecting human health without relinquishing the economic efficiency and viability. As such, green engineering is not actually an engineering discipline in itself, but an overarching engineering framework for all design disciplines.

Green engineering adheres to nine guiding principles. A designer must strive to:

1. Engineer processes and products holistically, use systems analysis, and integrate environmental impact assessment tools.

2. Conserve and improve natural ecosystems while protecting human health and well-being.

3. Use life-cycle thinking in all engineering activities.

4. Ensure that all material and energy inputs and outputs are as inherently safe and benign as possible.

5. Minimize depletion of natural resources.

6. Strive to prevent waste.

7. Develop and apply engineering solutions, while being cognizant of local geography, aspirations, and cultures.

8. Create engineering solutions beyond current or dominant technologies; improve, innovate, and invent (technologies) to achieve sustainability.

9. Actively engage communities and stakeholders in development of engineering solutions.

The American Chemical Society has expanded these to twelve principles:

1. Inherent Rather Than Circumstantial - Designers need to strive to ensure that all materials and energy inputs and outputs are as inherently nonhazardous as possible.

2. Prevention Instead of Treatment - It is better to prevent waste than to treat or clean up waste after it is formed.

3. Design for Separation - Separation and purification operations should be designed to minimize energy consumption and materials use.

4. Maximize Efficiency - Products, processes, and systems should be designed to maximize mass, energy, space, and time efficiency.

5. Output-Pulled Versus Input-Pushed - Products, processes, and systems should be "output pulled" rather than "input pushed" through the use of energy and materials.

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

7. Durability Rather Than Immortality - Targeted durability, not immortality, should be a design goal.

8. Meet Need, Minimize Excess - Design for unnecessary capacity or capability (e.g., "one size fits all") solutions should be considered a design flaw.

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Wikipedia