Definition of Waste

Waste refers to materials with negative utility in their present state.

This definition acknowledges that waste is a physical entity, under a conditional state, at a specific moment in time. It allows for a very precise categorization that does not require an extensive navigation of the complexities inherent to materials and their contexts. To fully comprehend it, its components must be examined, recognizing that while each condition is necessary, none is individually sufficient to classify something as waste.

Condition	Explanation	Examples
Materiality	Waste is a physical and tangible entity made of matter, that can be interacted with in the physical world, making its management and impact practical. In the field of emissions, waste refers to solid and liquid material streams.	Industrial scraps from a production process are physical and tangible. In contrast, noise pollution from the involved machinery can also be harmful to humans, but it does not consist of matter, therefore being excluded from the definition of waste.
Negative Utility	Derived from economics, utility is the potential of something to affect human needs or desires. Positive utility implies the potential to satisfy needs, while negative utility is related to dissatisfaction, harm, or a net loss of value.	In a restaurant, used cooking oil is a byproduct of cooking processes. In countries where biodiesel production exists, it can be sold to oil collectors. However, if there are no means to process or sell it, it remains waste due to its negative utility (e.g., disposal issues, potential environmental harm).
Present State	Waste is not an inherent property but a condition dependent on the material's current state and context. Valuable materials can become waste and waste can regain value as a resource.	When plastic bottles are collected and sorted, they gain value and become recyclable materials. In this state, they are not considered waste due to their potential for reuse. However, when these same bottles are mixed with other garbage, their utility diminishes significantly, rendering them waste due to the high cost and effort needed to process them.