2018 Champion City

Princeton, NJ : 2018 Champion City

Reducing Food Waste in Princeton

  • 31,249

  • Liz Lempert

  • Directly Elected Mayor

    Type of Government
  • 4 years

    Length of Term
  • Climate

    Issue Area

The Problem

Almost 25% of Mercer County trash is food and organic waste, which produces abundant methane when left to decompose in the landfill, and, so far, there is no proven or efficient strategy to fix this issue.

The Idea

The municipality of Princeton will use behavioral science to develop interventions to reduce food waste, and install a local food digester to turn the waste into compost for local farms, keeping organics out of landfills and reducing methane gas emissions.

What Liz Lempert, Mayor of Princeton, NJ is saying:

I am thrilled at this opportunity for Princeton to develop a decentralized system to recycle food waste back into compost. Our idea has the potential to significantly reduce greenhouse gas emissions and hauling costs while, at the same time, enhancing the health and productivity of our local soils.


Our Prototyping Journey

    Let's Go

  • How we are testing our data

    Our idea will impact the residents who want quality food, farmers who want wholesome soil and other communities who want to duplicate this idea.

    Jeff Groser, Assistant Administrator

    Princeton will test resident motivation to participate in a composting program. Using behavioral nudges, the city will assess how to encourage composting practices. By running Monte-Carlo analyses and location proximity tests, the city will assess its ability to manage the food conversion process.

  • Ideas into Action

  • What we're discovering through testing

    The team began by doing a lot of tests around signage and communications with the public. The team has been challenging their assumptions around composting behaviors by placing compost bins at different community events and observing citizens’ behaviors around them. They then interviewed citizens to better understand the "why" behind their behaviors. One clear finding emerged - that once a behavior is learned and becomes automatic, it is very difficult to change.

    From the last checkpoint with the advisors from @BloombergDotOrg a week ago. We helped mayor @lizlemp and her team synthesize ideas, findings & pivots and create workstreams to achieve our goal of making composting available city wide. #MayorsChallenge #PrincetonChampionCity

    4:38 PM - 17 Jul 2018   TeamSWIFT18  

    Through testing, the team has noticed how often Princeton residents talk about the feeling of guilt as part of the composting experience. People feel guilty that they’re not composting enough, guilty that they're not composting the right things, and even guilty that they could be producing more compost if they didn’t fill the bin all the way. Going forward, the team are looking to explore this aspect further, and the impact of guilt on resident behavior.

    #FunFriday! We’re redesigning the compost bin today to address passerby contamination, pests, smell, liquids, consistency issues etc. Here are some quick & fun prototypes of our ideas! @lizlemp @BloombergDotOrg #MayorsChallenge What improvements do you want for your bin?

    2:37 PM - 20 Jul 2018   TeamSWIFT18  

    We learned it wasn’t as simple as putting up the right picture and people would get it.

    Matthew Wasserman, Project Manager
  • Reflections

  • What we've learned

    The team have discovered the potential of the ‘community’ to drive behavioral change. They are moving their focus from individual to collective behavior; in particular, how people are impacted by their perception of what their community is doing. When the city asked residents if they would like incentives to join the program, many said they see it as a community service, and that offering rewards would undermine the idea. The team are now conducting further tests around community.

    How much food waste is in your trash? We conducted a trash audit to get a baseline and the amount came out to ~50%. How much will that change if those residents composted for a week? Find out next week! @lizlemp @BloombergDotOrg #MayorsChallenge #johnstreettest #princetoncomposts

    11:52 AM - 7 Aug 2018   TeamSWIFT18  

    We’ve heard a lot of positive feedback about the program; people like giving back, they like feeling part of a larger initiative and helping the city.

    Emma Thomas, Princeton University