Students develop technology that measures dumpster usage

Juniors Ben Backus and Nathan Poczekay built a sensor that can measure how much waste Stanford students are putting into dumpsters. The technology is helping Stanford Residential & Dining Enterprises manage student waste.

Ben Backus, ’20, and Nathan Poczekay, ’20, do not fit the typical profile of students working in sustainability. Rather than entering the field through tracks such as Earth Systems or Public Policy, the students are Symbolic Systems and Mechanical Engineering majors, respectively. Neither had worked in sustainability prior to the 2018-19 academic year.

Backus places sensor in dumpster.

Ben Backus, ’20, places the waste sensor inside a dumpster at Wilbur Hall. (Image credit: Nova Meurice)

Yet thanks to their efforts in building a waste sensor for dumpsters – as a part of their Residential and Dining Enterprises (R&DE) Zero-Waste internship – Stanford is able to collect accurate data about student waste habits and dumpster servicing in real time.

Each spring as students move out of their residences, waste production nearly doubles as compared to normal outputs. In light of Stanford’s recent pledge to become a zero-waste campus by 2030, this uptick provides not only logistical challenges in waste maintenance but also a hurdle to reducing student-generated landfill waste.

In 2018, R&DE’s Office of Sustainability and Utilities monitored dumpsters for the two-week move-out period at the end of spring quarter to better understand student waste habits and dumpster servicing. At the time, this process required R&DE employees to spend early hours of the morning, before service trucks arrived, peeking over the rim and visually rating the fullness of a dumpster on a scale of 1 to 4.

Until recently, these visual checks (known as “waste audits”) and the manual sorting of the dumpster’s contents, were the only ways of obtaining waste data. Measuring the efficacy of new signage or waste receptacles then meant making subjective observations at dumpsters.

Last fall, Backus asked Sea Gill, Stanford’s sustainability and utilities coordinator, to provide suggestions for a project. That’s when Gill gave him the idea for the sensor.

“It definitely feels nice to be able to tell people that the thing that you’re working on is going to make the world a better place.”

—Ben Backus, ’20

Backus began developing the sensor hardware, which works by sending radio waves across the dumpster and forming a rough model of the contents based on the response. The sensor is also equipped with a motion detector that gathers information about when students are using a dumpster, and a tilt switch that indicates when the dumpster has been emptied. All of this data is then sent to servers in real time. After working solo on the sensor for a few months, Backus asked his friend, Poczekay, to help him with some of the software and circuit board development aspects of the sensor.

The data the sensor produces provides a better understanding of when, and how often, students are using the dumpster. This information in turn will allow the Office of Sustainability and Utilities to create better interventions to reduce student waste as well as potentially create more efficient routes for haulers so they only need to empty dumpsters that are full.

The sensor has been tested and is fully operational. Spring quarter it was placed on a landfill dumpster serving Arroyo and Cedro houses in Wilbur Hall. It will return to the same dumpster fall quarter when Backus and Poczekay are back on campus and able to monitor it.

“I thought that this project was really cool because I could actually apply what I’d learned [in the classroom] to a real problem and see the impact in my community,” Poczekay said.

Backus, who has a background in web development, said that the R&DE internship gave him the opportunity to try working with hardware. He says it’s fun to tell people that he works with dumpsters, and he’s grateful for the new technical skills he’s acquired and seeing tangible results produced by the sensor.

“This is a huge blessing because now I’ll be able to put on my resume that I have demonstrated certain electrical engineering skills,” Backus said. “When you’re building a web application, it’s all built in code, which is just theory, but in the real world things are messy.”

Although Backus and Poczekay are unsure of their exact career trajectories, they feel that this project has informed what they want their futures to look like.

“It definitely feels nice to be able to tell people that the thing that you’re working on is going to make the world a better place,” Backus said.