Industrial ecology (IE) is the study of how materials and energy move through industrial systems. The global industrial economy can be seen as a network of processes that take resources from Earth and change them into by-products, products, and services that people buy and use. Industrial ecology focuses on measuring these material flows and recording the processes that support modern society. Industrial ecologists often study how industrial activities affect the environment, use of natural resources, and waste disposal. Industrial ecology is a new but growing field that combines ideas from engineering, economics, sociology, toxicology, and natural sciences.

Industrial ecology is described as a "systems-based, multidisciplinary discussion that aims to understand how complex human and natural systems work together." The field looks at sustainability by examining problems from different angles, such as sociology, the environment, the economy, and technology. The name comes from the idea that natural systems can help guide the design of industrial systems that are sustainable.

Overview

Industrial ecology focuses on changing how industries use resources. Instead of using a linear system, where resources and money move through a process and become waste, industrial ecology uses a closed-loop system. In this system, waste from one process can be used as a resource in another.

Research in industrial ecology includes:
• studying how materials and energy move through industries
• using fewer materials and reducing carbon emissions
• how technology changes and affects the environment
• planning, designing, and evaluating the life of products
• designing products to protect the environment
• making producers responsible for the entire life of their products
• creating industrial areas where businesses share resources
• setting policies that focus on products and their environmental impact
• making industries more efficient while protecting the environment

Industrial ecology helps understand how industrial systems, such as factories, regions, or economies, work with the natural world. Natural ecosystems show how different parts of a system can work together without waste. These systems use resources and infrastructure, not just natural resources. Industrial ecology uses this idea to create sustainable designs.

Industrial ecology is one of four goals in Natural Capitalism. This approach includes saving energy and materials, changing how international trade and product responsibility are managed, and treating these as services. It discourages buying products without knowing their full impact. It also supports a system that values natural resources and uses knowledge and education to design and maintain each industrial system.

History

In 1989, Robert Frosch and Nicholas E. Gallopoulos introduced the idea of industrial ecology in an article published in Scientific American. They asked, "Why can’t our industrial system work like an ecosystem, where waste from one organism becomes a resource for another? Why can’t the waste from one industry become the raw material for another, reducing the need for new resources, pollution, and the cost of waste treatment?" A well-known example of this concept is found in Kalundborg, Denmark. In this industrial park, multiple businesses, such as a power plant, oil refinery, medicine factory, and waste management company, share resources like waste materials and heat. Another example is the Rantasalmi EIP in Rantasalmi, Finland. While Finland had earlier industrial parks that formed naturally, the Rantasalmi EIP was the first in the country to be planned intentionally.

The field of industrial ecology has grown rapidly. Organizations like the Journal of Industrial Ecology (started in 1997), the International Society for Industrial Ecology (founded in 2001), and the Progress in Industrial Ecology journal (launched in 2004) help industrial ecology become an important area of study worldwide. Industrial ecology ideas are also being used in policies, such as the circular economy. Though the exact definition of the circular economy is still being developed, it generally focuses on strategies like reusing materials and using energy from one process to power another process that needs less heat. These strategies aim to make economies more efficient and reduce pollution and unwanted waste.

Examples

The Kalundborg industrial park is located in Denmark. This industrial park is unique because companies share and reuse each other's waste, which becomes useful materials for other businesses. For example, the Energy E2 Asnæs Power Station creates gypsum as a leftover material during electricity production. This gypsum is then used by BPB Gyproc A/S to make plasterboards. This is an example of a system inspired by how nature works: in ecosystems, one organism's waste becomes food for another; in industrial systems, one company's waste becomes a resource for another.

In addition to reducing waste, using an eco-industrial park can help make renewable energy sources, such as solar panels, more cost-effective and better for the environment. This supports the growth of renewable energy and helps reduce the use of fossil fuels.

Other examples of industrial ecology include:

• Using ash from burning coal instead of cement in concrete.
• Creating biodiesel from cooking oil or grease to power vehicles.
• South Africa's National Cleaner Production Center (NCPC) helps industries use materials more efficiently. This reduces energy costs and improves waste management. The program checks companies to find ways to improve their practices.
• Reusing water that is not clean enough for drinking for other purposes.
• Making biodegradable plastic from chicken feathers, which are mostly made of a protein called keratin. These feathers are waste in the EU and US, but they are turned into plastic products that break down easily in soil.
• Toyota Motor Company captures some greenhouse gases and uses them as heat energy in their systems.
• Anheuser-Busch partnered with a company called Blue Marble to use waste from beer production to make eco-friendly products.
• Petra Nova uses leftover oil to help extract more oil from the ground.
• Reusing cork from wine bottles for shoe soles, floor tiles, insulation, car parts, crafts, and soil improvement.
• A building in Sydney, Australia, recycles and reuses its wastewater.
• Using plant-based plastic packaging that can be fully recycled and is safe for the environment.
• Turning food waste into compost, which can be used as fertilizer for growing food. Uncontaminated food waste can also be used to feed people who need food.
• The Hellisheiði geothermal power station uses groundwater to generate electricity and hot water for the city of Reykjavik. Its carbon waste is injected back into the ground, where it turns into rock, making the station have no net carbon emissions.

Future directions

The ecosystem metaphor, introduced by Frosch and Gallopoulos, has helped researchers find new ways to solve difficult problems. This metaphor is based on traditional ecology models. However, recent research by scientists like C. S. Holling and James J. Kay has expanded understanding of ecology using complexity science. In industrial ecology, this could mean moving from a simple, mechanical view of systems to one where sustainability is seen as something that naturally arises in complex systems. Researchers are now using agent-based modeling to study these ideas further.

Exergy analysis is a method used in industrial ecology to improve energy efficiency. The term "exergy" was first used by Zoran Rant in 1956, but the concept was developed earlier by J. Willard Gibbs. In recent years, exergy has been applied in fields beyond physics and engineering, including industrial ecology, ecological economics, systems ecology, and energetics.