Kicking Contamination from the Curb: How New Feedback Mechanisms Can Increase Opportunities for Recycling

Key Takeaways

  • Much of the responsibility for advancing the circular economy has been directed towards firms, yet many reuse opportunities can only be achieved through environmentally compliant, household-level recycling behaviors.
  • Fortunately, if leveraged correctly, curbside feedback mechanisms can be effective tools to enhance opportunities for material reuse.

Households in the United States (U.S.) recycle over 11 million pounds of paper, plastic, cardboard, aluminum, glass, and other materials annually via curbside and municipal collection (The Recycling Partnership 2020). Estimates suggest that the annual environmental impact of reusing these materials equates to eliminating 30 million metric tons of CO2 equivalent emissions, conserving 50 million barrels of oil, and taking more than 7 million cars off U.S. highways annually (The Recycling Partnership 2020).

While much of the responsibility for advancing opportunities for reuse has been directed towards firms, studies continue to reveal that many reuse efforts and opportunities can only be achieved through environmentally compliant, household-level recycling behaviors. For example, despite strong incentives, recyclable materials are increasingly at risk of being landfilled due to dramatic surges in contamination rates. Contamination occurs when unaccepted or non-recyclable materials are placed in recycling bins and is an outcome of activity within the household. In the United States, the average contamination rate of collected recyclables is currently 18%, well above key market limits of 0.50%. As the costs to recycle are already near that of the cost of landfill

tipping fees, such high levels of contamination rates are unsustainable and jeopardize the future of U.S. recycling programs. As an illustrative example, the city of Columbus, Ohio pays $35 per ton for recycling and $40 per ton for materials sent to the landfill. In this article, we explore the question: How can waste management companies motivate consumers towards sustainable recycling practices?

One mechanism for reducing contamination, which has become popular in recent years, is the use of curbside audits & feedback. Through this method, households receive feedback on their recycling performance at their recycling carts. Curbside recycling has existed for over 30 years and 70 million households have access to these services. During the auditing process, a recycling professional reviews the contents of a household’s recycling container. There are up to three different outcomes that follow an audit. If the recycling container does not have any contaminants, then there is no information shared with the households and their contents are picked up by the collector. If a contaminant is found, then the households can receive a cart warning wherein their recycling bin is tagged with an information card highlighting which item(s) were improperly recycled. The presence of a contaminant can also trigger a cart-refusal response wherein the resident will also receive an information card, but in this case, the household’s recycling bin will not be emptied.

Up until recently, the effectiveness of curbside feedback tactics had not been formally tested, and recycling industry stakeholders remained divided on the success of cart warning and cart refusal feedback mechanisms. However, our team recently engaged in a study in collaboration with the Solid Waste Authority of Central Ohio (SWACO) where we analyzed feedback and performance data from nearly 26,000 curbside audits across 12,000 households in Columbus.

We found that information-only methods (e.g., cart warnings) have limited effectiveness and are typically only helpful in nudging behavior in higher income areas. In contrast, our results indicated that cart-refusals involving punitive mechanisms can dramatically reduce violation rates. Specifically, households that receive punitive feedback in the form of cart-refusals reduce their number of categories of contaminants by an average of 59% and are 75% less likely to commit a violation in the future.

Another finding from this study is that overall punitive mechanisms do not discourage household participation (as measured by set out rates), but rather increases future recycling rates. However, the results from a post-hoc analysis indicate that these mechanisms should be used with care in areas with older populations-- as household age increases, the effect of cart-refusals on set out rates can become negative. This suggests that the mechanism has the potential to be discouraging to older individuals. Finally, in a supplementary analysis, we found that cart refusal mechanisms are most effective in reducing the presence of aspirational contaminates and changing the behaviors of households located in areas with moderate to high education levels, moderate to high incomes, and low to moderate population densities.

Over 100 communities within the U.S. have seen their local recycling either significantly curtailed or cancelled due to unmanageable contamination. (Waste Dive 2019). Fortunately, if leveraged correctly, curbside feedback mechanisms can be effective tools to enhance opportunities for material reuse and engagement in sustainable behaviors.

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