The circular economy

Authors: Edward Tivnan, Meredith Malott

 

Imagine a world where nothing goes to waste, and everything can be used again. That’s what the circular economy is all about. Instead of throwing things away, we find ways to reuse, fix, or recycle them. For example, old clothes might be turned into new fabric, or food scraps might be turned into compost for gardens. A system where materials are repurposed, repaired or recycled and do not become waste is a circular economy. By adding value or valorizing these materials we utilize the circular economy principles to prolong the life of products from nature.

Now, when we use nature’s resources to create new things, it’s called the bioeconomy. This means we grow or gather materials directly from nature to make useful products. Some cool examples are growing fruits and vegetables, creating new vaccines to keep us healthy, or discovering new medicines from plants. So, the bioeconomy is like using nature’s gifts to help make life better! A great example of the bioeconomy and circular economy working together is when we turn food scraps into composting to enrich the soil in our gardens.

Products from the bioeconomy that come from plants or animals and are not made from fossil fuels are called biomass. An example of this would be cow manure. An efficient way to use biomass is through cascading. Cascading is the process within a circular economy which one waste product of a system is used in another system. As with our cow manure example we can reuse this for fertilizer on a farm, using the nutrients to help the crops grow. This is an example of the cascade of a biomass into a new product.

 

Figure 1 shows how a linear economy functions. Today, a linear economy is common practice. In this system, we take resources, make products, use them, and then throw them away, creating waste. Figure 2 shows a circular economy, which is a vision for the future. In a circular economy, products are designed to last longer, be reused, and then recycled, so there's little to no waste. Just like in nature where a plant may release oxygen as a waste product, but it is vital to the survival of humans and animals. This process is like nature’s way of recycling and “closing the loop.”

Aquaponics provides a good example of bioeconomy principles. Aquaponics uses three interdependent keystone communities: fish, plants, and microbes, to grow food.

Fish, plants and microbes keep each other healthy by using each other’s waste. The fish metabolic waste is mostly ammonia, a compound of nitrogen. If ammonia builds up in the fish tank, it becomes toxic to the fish and can be deadly. Microbes in the water convert the ammonia into another form of nitrogen, called nitrates, which are not harmful to the fish. This nitrogen is an essential nutrient for plants to grow. This type of interdependence is called a symbiotic relationship, whereby each member helps the other to thrive. The fish provide nutrients through their waste, the bacteria convert the waste into absorbable, nontoxic nutrients and the plants are given the means to grow. Consequently, aquaponics is a “closed loop” agricultural food production system.

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Summary

1. The Bioeconomy refers to that side of the Circular Economy that is biologically based.
2. The current Linear Economy produces waste. The future Circular Economy aims to reduce our carbon footprint.
3. Cascading means making biomass into a useful new form, rather than throwing it away,
4. Valorizing means taking “waste” and using it for something useful or more valuable.
5. Aquaponics is a closed loop agricultural food production system.

Review Questions

What is the basic difference between a Linear versus a Circular Economy?

What does Bioeconomy mean? Give three examples.

What are the three major Keystone Communities in Aquaponics Systems? How do they use each other's waste?

Underlined Vocabulary Words

1. Aquaponics: The production of food using fish, plants, and microbes.
2. Bioeconomy: the biological side of the circular economy.
3. Biomass: living things like wood, grass, soybeans, clamshells, etc.
4. Cascading: making something into a more useful form.
5. Circular Economy:  An economy that works circular: Consume-Collect-Process-Design & Manufacture
6. Keystone communities: groups of living things that heavily impact nearby communities.
7. Linear Economy: An Economy that works linear: Extraction-Supply-Manufacturing Waste.
8. Metabolic: pertaining to an organism’s chemical reactions that keeps them alive
9. Symbiotic relationships: organisms that help each other to thrive.
10. Valorizing: making something more valuable

 

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Review Questions Answers

What is the basic difference between a Linear versus a Circular Economy?

Answer: The Linear Economy takes from the Earth’s resources, makes products, and disposes them in a linear sequence. The Circular Economy, like nature, creates no waste because everything is designed to last longer, to be reused, and then recycled in a continuous circle.

What does Bioeconomy mean? Give three examples.

Answer: The biological side of the Circular Economy. Three Examples of Biomass products are: Fruits (i.e. Apples and Oranges), Vaccines (i.e. Trade name polio vaccines Ipol and Poliovax) and Medicines (i.e.  Penicillin) There are many, many more.

What are the three major Keystone Communities in Aquaponic systems? How do they use each other's waste?

Answer: Fish, Plants, and Microbes.  The fish metabolic waste is mostly Ammonia which is a type of Nitrogen. Plants love Nitrogen! If Ammonia builds up in the fish tank it becomes toxic to the fish and will kill the fish. The microbes in the water convert the Ammonia into another form of Nitrogen called Nitrates which is food for the microbes and the plants. Yet Nitrates are non-toxic to the fish and keep them healthy.