2. Reuse versus recycling – a discussion in the class

In this exercise, you are to work with the concepts of reuse and recycling with the purpose of understanding the terms, applying them, and gaining insight into the difference between the two.

Teacher's guide

2. Intro_EN.pdf

En collage med forkellige byggematerialer.

Reuse or recycling?

How do you determine if a building material that has been used before is reuse or recycling?

The crucial factor is fundamentally whether the material is utilized for something resembling its original function or if the material has been processed to be used for a different function.

The Difference between reuse and recycling

It is challenging to draw a completely sharp line between when it is considered reuse and when it is considered recycling. There are a few characteristics to look for when making this distinction.

Definition of reuse and recycling

Reuse is when dismantled building material is used for the same or a similar function as it was originally used for. Bricks are used as bricks, and timber is used as timber. The building material is taken out of one structure and incorporated into a new one, where it serves the same function.

Recycling is when the material is transformed and processed so that it can be used for something other than its original purpose. It could be bricks crushed and used as road fill, or wood divided and used as fuel. This is also referred to as 'downcycling'. The material gets a new 'life' with new properties that make it suitable for different functions. However, for most recycled materials, they cannot be brought back to their original form.

This way of understanding the difference between reuse and recycling is not entirely comprehensive. There are examples of building materials that, after the initial use, are transformed into another material before being used in the production of a similar building material to what it originally was. Is this then reuse or recycling? In these cases, it makes sense to look closely at how much the material has been processed.

Another way to determine whether it is reuse or recycling is by examining the processes that occur after demolition. Here, you can differentiate between reuse and recycling by categorizing materials based on whether they can be transported directly from demolition to a new construction site where they are reused directly (reuse), or if the material is transported from demolition to a manufacturing facility where it is used in the production of a new material (recycling).

This is illustrated in the lifecycle diagram, where reuse is depicted by the path from demolition to incorporation, and recycling is shown by the path from breakdown to production and further to incorporation.

Both reuse and recycling preserve raw materials, limiting the need to use new raw materials, as illustrated in the top-left corner of the diagram. The advantage of reuse over recycling is that it saves the energy required to process the material and transform it into something new.

Duration: 55 min.

Reading: 15 minutes

Task: 40 minutes

Reuse

The concept of reuse involves using a product or an item again, as it is, without altering its form or character.

Recycling

The concept of recycling involves using an already used product to create a new product. Recycling requires that the product undergoes some form of processing or manipulation of the original item to create something new.

Example of reuse

Reuse occurs when a material is used again in a new project while retaining its original form.

A notable example of a place that has implemented a high degree of reused materials is the Danish construction concept Upcycling Orangery. In this project, 17 tons of construction waste were utilized to construct an orangery exclusively using reused materials. Reused concrete elements, reused timber, reused glass, and reused bricks were all incorporated.

The reuse of these materials implies that relatively small amounts of energy were required to process them, compared to the energy that would have been needed to create new materials. In Upcycling Orangery, 9300 kg of CO2 emissions have been saved by employing reused materials.

 

Et rum med store vinduer, en grå murstensvæg, træspær og et bord med stole.
Upcycling Orangery, Aalborg, Denmark

Examples of recycling

Recycling occurs when a material is used in a different form than its original.

Here are examples of recycling:
Crushed bricks can be used as road fill under roads and paths, as a base for green roofs, as an aggregate in concrete, or in the production of new bricks.

En grusgrav.
Gravel pit, Denmark

Wood that is no longer suitable for other use can be chipped into wood chips, which can be used for temporary path systems or as fuel in heating systems.

En bunke med træflis.
Wood chips

Exercise - classroom discussion (40 min.)

You will now work on some exercises, including finding examples of reuse and recycling, which you will present to your class. Feel free to draw from your own daily life, but you can also use examples from other situations you are familiar with. Try to come up with five examples or as many as you can.

You may copy the questions into a document for easy registration of your answers to each question.

1. Describe reuse and recycling (5 min.)

  • Describe in your own words what reuse means.
  •  Describe in your own words what recycling means.

2. Examples of reuse and recycling (10 min.)

  • Provide 5 examples of reuse. Feel free to find examples from both your daily life and your education.
  • Provide 5 examples of recycling.
  • Find an example where you find it challenging to determine whether it is reuse or recycling.

3. With a classmate (10 min.)

  • Present your answers to a classmate, and vice versa. Select 1-2 of your best examples of reuse and recycling.
  • Together, choose one example where you think it's difficult to determine if it's reuse or recycling.
  • Write down at least three words or concepts (aside from reuse and recycling) that you encountered or thought of during today's lesson that were new, that you particularly noticed, that you didn't fully understand, or that you believe are particularly relevant to the discussion on reuse and recycling.

4. Presentation for the class (15 min.)

  • Share your descriptions of reuse and recycling and find out if everyone in the class agrees on the difference between the two.
  • Present the best examples to your class, as well as the example where it is challenging to determine. Try to collectively agree in the class whether it is reuse or recycling.
  • Share which new words or concepts you have chosen.