A Reverse Vending Machine is a device that pays you money to deposit something into it.
Vending machines take your money and give you things. Those things usually come in packaging that most people just throw away.
A reverse vending machine (RVM) works the other way round: you put things into it, and the machine “pays” you in some way. Although the idea of collecting items that would otherwise go to waste was first patented in the US in 1920, it has only become popular in recent years as a tool to promote sustainable behaviours - and even then, only mostly in locations that have strong conservation regulations/laws or significant garbage/pollution problems.
One interesting case of the application of these RVMs is in the Beijing Subway, where you can (partially) pay for your subway usage by depositing plastic bottles into a machine, shown in figure 1, made by Incom Recycle. Because the machine immediately crushes the bottle, one machine can store many, many plastic bottles.
Using these machines requires some special consideration, however. In cultures that place significant prestige and social value on proper recycling (such as China and Japan), these machines can be very helpful. However, in places where people wouldn't particularly care what they throw into it, they could easily malfunction. Clearly, different machines are needed to process different types of materials or objects. Careful attention must be paid to the design of the user experience and user interface to guide people into doing the “right thing.”
Furthermore, one would like to position these machines in locations where it is most likely people will pass who (a) have objects to deposit, and (b) have the time to spend depositing their objects and claiming their financial rewards.
There is one very significant problem with such machines, however. Since they promote getting rid of garbage sustainably - and therefore makes people “feel good” about doing the right thing - they also promote people consuming more overall. This is a classic case of the Jevons Paradox, in which increased efficiency (in this case, of material usage via recycling) actually increases consumption overall rather than decreasing it.
Another problem - one systemic to many garbage solutions that involve recycling, especially those for recycling plastics - is that some materials cannot be indefinitely recycled. They are, instead, “down-cycled” a few times before the material becomes entirely useless and must be land-filled.
Still, the use of such machines does “buy time” for a community faced with sustainability problems. Even if Jevons Paradox holds, these machines do tend to slow the rate, temporarily, by which materials are irretrievably consumed. By slowing down the rate at which true garbage is generated, it provides the society (a system) the time to adapt to new circumstances. For instance, in the case of RVMs, they can buy a society time to educate the citizenry on over-consumption and change societal norms to favour a more minimalist lifestyle.
Exercise for the Reader Draw a system diagram (such as a stock and flow diagram or a causal loop diagram) representing a specific situation (e.g., a small town or community, or even just a subway or bus station, or shopping mall) and consider all the feedback loops that can influence not only the use of the RVM, but other factors affecting the situation such as overall consumption, attitudes of users, other technologies and industries, and so on.