by Stavros Mouslopoulos

The message from physics regarding waste is robust: 'Waste in any form is here to stay since it relates to our existence and all physical processes'.

But this message is not hopeless since we humans, gifted with consciousness and free will, have the unique ability to predict and measure the effect of our actions. We can modify these actions to minimize waste and when possible exploit all byproducts as a new source of energy.

So how is waste related to the laws of physics?

Physics has a powerful statement about waste: The Second Law of Thermodynamics. This is perhaps one of the most fundamental and universal principles in physics. It applies to all processes and every level of the physical world.

This law states that: In any system, a process that occurs will tend to increase the total entropy of the universe.

In practical terms this means it is impossible to have a 100 percent completely efficient thermodynamic process. Given this, any process in the universe will evolve in such a way that part of the energy content will change into a form that will not be useful for the initial (primary) process. Hence will be wasted.

This does not imply that this energy is lost. The Law of Conservation of Energy states this cannot occur. This law says: Energy can transform from one form to another however it cannot be destroyed or created. This energy can however become devalued. In physics this is called increased entropy. This means it is harder (but not impossible) to exploit the energy in a profitable way.