Landfills are a major contributor to methane emissions in the United States. By diverting organic waste from landfills, composting may reduce the global warming effects caused by methane. However, only a small proportion of compostable food is currently composted. This is because of barriers to composting that are both structural (lack of public composting infrastructure) and psychological (insufficient knowledge about and interest in composting among prospective users).

We set out to develop a municipal composting program for the city of Durham that meets the needs of both city staff and residents. We did so by prioritizing behavioral science, human centered design, and rigorous qualitative and quantitative program evaluation. After developing the program through prototyping and a pilot limited to one neighborhood, we adjusted the program based on findings and user feedback. We then ran a 360-household randomized control trial to assess the program’s ability to divert foodwaste from the landfill.

In addition to studying the environmental benefits of the composting program itself, we also investigated the program’s ability to promote other beneficial behaviors. Drawing on previous literature about the salience of pro-environmental and pro-community self-identification, we hypothesized that-- by building a greater sense of pro-community and pro-environmental identity in participants-- the composting program may lead to increased pro-environmental and pro-community spillover behaviors We investigated this hypothesis in large part by conducting surveys throughout the randomized control trial.