The term ‘waste’ can be used as a verb, noun or adjective to refer to a substance or object, thoughtlessness, a missed opportunity or inefficiency (Davies, 2008, p. 4). Waste can be solid, liquid or gas and can be hazardous or toxic. Zero waste theory embodies all these connotations and forms of waste, defining waste as anything unusable, unwanted and unrecyclable [1]. This is in contrast to the conventional understanding of waste as any discarded material (EPA, 2010b).

The terms unusable and unwanted are purposely subjective. They are meant to convey that waste is not an intrinsic property of any item (Palmer, 2004). As the idiom ‘one man’s trash is another man’s treasure’ conveys, changing the owner of any object can change the status of an item from waste to wanted (Palmer, 2004). To eliminate the conception that all discards are waste, some zero waste theorists have suggested the term be changed to ‘municipal solid discards’ to allow for the perception that discards may be potentially usable, wanted or recyclable (as cited in Leonard, 2010, p. 190).

Due to the subjective nature of the terms, establishing whether or not an item is usable or wanted is not straightforward. Each item must be analyzed from a broad perspective considering the potential usage or value of the item to someone else.

Some theorists go so far as to claim that “all discards can always and should always be preserved for commercial reuse” as there is potential that someone, somewhere may want, be able to use or recycle the discard in the future (Urban Ore, n.d.3). How or where such discards are to be preserved presents another challenge and one that will have to be addressed elsewhere. The argument to preserve all discards is related to the zero waste community’s rejection of incineration. Preserving discards allows for the possibility that such resources could be reused whereas incineration destroys all resource value and landfilling can irreversibly contaminate resources (Knapp & Van Deventer, n.d.; Palmer, 2004).

Once usable and wanted objects have been reclaimed as non-wastes, zero waste theory dictates that recyclable objects and materials are also not waste. Recycling is defined by the U.S. Environmental Protection Agency (EPA) as, “the series of activities by which materials that are no longer useful…are collected, sorted, processed, and converted into raw materials and used in the production of new products” (Pillsbury, 1997). Zero waste theory adds an extra stipulation to this definition.

For a material to be declared recyclable under zero waste theory, no waste must be created at any point during this series of activities. Furthermore, the material subject to recycling must be infinitely recyclable. It is not acceptable for materials to be recycled into a product that in turn cannot be recycled, a practice referred to as delayed disposal.

Recycling processes that adhere to zero waste theory are referred to as closed-loop, total or universal recycling, where all resources and discards are fully contained and infinitely reused or repurposed within a grand, circulating system (Knapp & Van Deventer n.d.; McDonough & Branungart, 2002; Palmer, 2004). In order for this system to be possible, all materials and goods must be designed, from the beginning, to be effectively and efficiently recycled.

Although many municipalities have recognized that recyclable objects are not waste, current recycling processes often produce waste and result in delayed disposal. Much of this waste is created because the objects being recycled were not designed to be recycled in the first place.

Waste is a term so ubiquitous that is often evades explicit definition. Within official waste literature, definitions for solid, hazardous and other specific types of waste are readily available but explicit definitions of the singular term ‘waste’ are rarely noted. This is true even within the zero waste community as theorists demand that waste must be avoided but often neglect to define the key term.

Embedding the subjective elements of unusable and unwanted within the definition of waste ensures that objects and materials cannot automatically be assumed to be waste. As well, those materials and objects that can be recycled in closed-loop systems as resources for something new are also not waste.

While zero waste theory suggests that all discards should be preserved for potential future use or recycling, it is entirely possible that perfectly usable items may simply be forever unwanted for superficial reasons. It is also possible that technology to efficiently and effectively recycle all items within a closed-loop system may never develop.

Zero waste theory recognizes that within current systems, much waste is produced and there are many things that are not usable, wanted or recyclable. To this point, the theory demands that these items and materials are banned from production. All future designs must ensure that all products are perpetually usable, wanted and recyclable.

Zero waste elements
1. Waste is anything unusable, unwanted and unrecyclable
2. Zero waste is a visionary goal
3. Waste must be avoided, not minimized or reduced
4. Waste is evidence of poor design
5. Utilize the precautionary principle to eliminate potential toxins
6. Adhere to the principle of highest and best use
7. Recognize and address institutional and ideological barriers