The ComPOSTer: Alum Profile – Kiley Coates ’20

This week at the ComPOSTer we take a quick break from Campus as Lab updates to catch up with the second S.C.R.A.P. Lab operational assistant to graduate this spring – Kiley Coates ’20.

Read below about how Kiley’s time working at the S.C.R.A.P. Lab has framed her views of sustainability on different scales and has helped in her transition to the workforce as a lab technician processing COVID-19 test samples.

Kiley’s involvement with the S.C.R.A.P. Lab can’t be overstated – she worked 220+ hours over the course of 10 months and wrote an analysis of the composting process for her senior thesis.

“I worked at the S.C.R.A.P. Lab starting May 2019 and continued there until my time was unfortunately cut short due to COVID in March 2020. The S.C.R.A.P. Lab was a great way of learning about sustainability on a variety of scales. The S.C.R.A.P. Lab itself was a larger-type operation and I was able to learn about how institutions like Princeton could use this machinery to improve their in-house sustainability practices. On smaller scales, I learned a lot about various projects on Princeton’s campus and how to apply them even when I left Princeton (having my own compost pile, using reusable silverware even outside the home, etc.). Gina Talt, my supervisor, was a champion at promoting sustainability in practical ways, recognizing the nuances of environmentalism and the importance of doing what you can, while still acknowledging the class and cultural differences that may limit someone’s ability to participate in sustainable practices. 

After graduating, I started working for LabCorp in Durham, NC in their COVID Lab. My position as a lab technician involves primarily working on the queue of pending samples and ensuring we maintain our turn-around time and process priority samples efficiently. It’s definitely pretty different from my work with the S.C.R.A.P. Lab, but I definitely utilize problem-solving skills I grew during my time with Scrappy.”

Congrats Kiley!

Thank you for being such a dedicated composting champion at Princeton. Best of luck going forward!

The ComPOSTer: Students Designing Sustainable Systems

In the class ENE202: Designing Sustainable Systems: Demonstrating the Potential of Sustainable Design Thinking taught by Professor Forrest Meggers, students learn about solving the environmental problems facing today’s society with sustainable design principles. For the final course project, students worked on a group design project focused on improving sustainability on campus. In 2018, several students decided to work on projects related to the S.C.R.A.P. Lab and making operations more efficient. The first project was an effort to streamline the process of weighing food waste and using the data to promote awareness about the composter. The second project was an effort to use solar power to heat the S.C.R.A.P. Lab instead of electric heaters.

The first project was called “Hacking the [Composter]” and sought to streamline the process of recording food waste data and create a website that would allow the student body to keep track of the impacts of the program. This project was completed by Thomas Johnson ’19, Max McPherson ’19, and Patrick Brucki ’21 in the Spring of 2018 and was inspired by the idea to allow students to be able to more easily access information about food waste on campus. Though the students were unable to create a process to directly transmit the data from the scale to a spreadsheet due to technical limitations, they were able to collect data from the composter and make many graphics and figures to demonstrate the benefits of the S.C.R.A.P. Lab. An adaptation of their work is shown below.

Photo provided by Thomas Johnson ’19

The second project was called “Solar Air Heater” and sought to create a more sustainable heating system for the S.C.R.A.P. Lab using a solar air heater alongside a photovoltaic panel that would also spread awareness of alternate heating sources throughout the Princeton University community. This project was conducted in the Spring of 2018 by Lena Dubitsky ’18, Oliver Hsu ’19, and Izzy Mangan ’19. This team of students looked into solar air heaters after finding out that the S.C.R.A.P. Lab used electric heaters to keep the temperature inside the tent at least 40 degrees Fahrenheit. Though this temperature is crucial for the composter to function properly and sustain an active microbial population, the team of students noted that the use of electric heaters was inefficient and “was not on a similar level of sustainability” as the rest of the system.

Diagram of a Solar Air Heater: Photo sourced from:

Solar air heaters would be more efficient than electric heaters because they turn solar radiation into heat instead of turning heat into electricity and back to heat. This team of students built a prototype out of plywood, plexiglass, a solar panel, and black spray paint. This prototype was able to change the temperature at an average of 9.6 degrees Celsius which is very promising for the prototype but was not quite ready to be used in the S.C.R.A.P. Lab. The use of solar heating for the S.C.R.A.P. Lab will be investigated further when the facility relocates to Washington Road, but overall this project highlights the potential of integrating renewable energy systems within in-vessel composting operations so that they can be fully self-sufficient and closed-loop systems.

Prototype Solar Air Heater built by Lena Dubitsky ’18, Oliver Hsu ’19, and Izzy Mangan ’19. Photo provided by Lena Dubitsky ’18

The ComPOSTer: Introducing Wesley Wiggins and an Algae-based Class Project

Hello everyone! My name is Wesley Wiggins and I am the newest writer for the ComPOSTer. I am a Princeton University undergraduate in the Class of 2021 and I am concentrating in the Department of Geosciences while obtaining a certificate in Environmental Studies. I am a member of the Princeton University EcoReps and was the former co-president of the Princeton University Geosciences Society or PUGS. Additionally, I have been an Operational Assistant at the S.C.R.A.P. Lab since Fall 2018 so I’ve spent plenty of time with SCRAPPY and working with food waste and composting.

Wesley Wiggins ’21 in Cape Town, South Africa
Photo Credits: Linh Nguyen

In the Fall 2019 semester, I worked on a project which incorporated the composter for my class ENE321: Resource Recovery for a Circular Economy taught by Civil and Environmental Engineering Professor Z. Jason Ren. This class discussed the topic of a circular economy which is the idea that resources should be reused and repurposed instead of how our linear economy simply puts items into waste. Our final project for this course was to create a business idea and pitch for a company that incorporates elements of the circular economy, and when I first heard of this idea my mind immediately turned to compost. 

Composting takes food scraps and uses it to create a soil additive that enriches the earth which can assist in growing new food and/or keeping the environment healthy. My team also wanted to incorporate a new element and produce something from compost. Through our research, we learned that the process of composting emits biogenic CO2 and we wanted to repurpose that gas and produce something new. Our minds turned to the process of photosynthesis in which water and carbon dioxide contribute to building organic matter so we wanted to find a product that we could grow easily and then sell to consumers. This is when we came across the algae species, Arthrospira maxima and Arthrospira platensis more commonly known as Spirulina.

Spirulina (Arthrospira platensis and Arthrospira maxima) contains 55-70% protein by dry weight, as well as high amino acid content and nutrients. It grows best in environments with high CO2 concentrations, a high pH, and high temperatures.

Spirulina are a globally cultivated algae species for food production because of their high protein content and nutritional value. We decided that the nutritious algae would be an excellent food product to sell as our business product and the only thing left to decide was how to grow the spirulina. We decided that the best way to grow them and incorporate the compost would be to use a photobioreactor which is a closed system that would allow us to control the inputs and outputs of the spirulina growth mixture. We could also take the CO2 from an industrial composter like SCRAPPY and feed it into our photobioreactor to cultivate the spirulina.

A photobioreactor is a device that cultivates photosynthetic organisms in a closed system. The benefits of using this device is the ability to control both the inputs and outputs of the system with a decreased risk of contamination.

After settling on an idea, my team had to settle on a company name and company roles. The members of my team were myself as the Chief Technological Officer, Jivahn Moradian ‘20 as the Chief Financial Officer, and Gabby D’Arcangelo ‘21 as the Chief Executive Officer. When deciding on a name we wanted something that represented both the algae and the use of carbon dioxide from the composter. So the name we settled on was AlgaeHG or AlGHG. The GHG in the title is short for Greenhouse gases which we are using to create our product in the form of CO2.

Though the company was created for a class project, the three of us had quite a fun time brainstorming the science, engineering, finances, and algae puns for our little class project. And we were thankful to Gina and the S.C.R.A.P. Lab for letting Gabby and Jivahn visit the Lab during my shift, and for all of the other assistance, we were able to receive. 

Gabby D’Arcangelo ‘21, Wesley Wiggins ’21, and Jivahn Moradian ‘20 (from left to right) presenting the AlgaeHG business pitch and presentation in ENE321: Resource Recovery for a Circular Economy.
Photo Credits: Professor Z. Jason Ren

The ComPOSTer: Alum Profile – Milan Eldridge ’20

Happy dog days of summer everyone,

In about a month, classes at Princeton will resume, but before we head into the new academic year, the ComPOSTer caught up with one of the S.C.R.A.P Lab’s most recent alumni – Milan Eldridge ’20!

Although relatively new to the team, Milan was a fast learner whose passion for sustainable living made her an invaluable and dedicated assistant who took on multiple shifts even during her last semester at Princeton. Read more about Milan’s experience working at the S.C.R.A.P. Lab in her own words below:

I started working at the S.C.R.A.P. Lab at the beginning of my spring semester during my senior year. After becoming more involved with sustainability on campus, I wanted to continue to explore ways that I could be involved with sustainability within the campus community. I also wanted to learn more about sustainability on a larger scale so that I could carry what I had learned with me after graduation.

During my time on campus, I had seen the university change the company through which they composted. All of a sudden, we weren’t allowed to compost everything we had previously been allowed to compost in the dining halls. Soon, after spending some time in the Frist Late Meal Gallery, I started seeing bins labeled ‘S.C.R.A.P. Lab’. For a long time, I had no clue what the acronym stood for, only that we were meant to put our compost in the bin. After reading more about the S.C.R.A.P. Lab, I thought it would be a great opportunity to expand my knowledge of what the university was doing to combat food waste and help contribute to the goal.

“Sustainability can take many forms and may look different in different places depending on the limitations of each place” Milan Eldridge ’20

While working at the S.C.R.A.P. Lab, I quickly learned that, while the university produces a great deal of food waste, people are willing to do what they can in order to reduce the impact this has on the planet. This ranged from various academic departments keeping compost buckets to student groups like Coffee Club searching for ways to keep their business as sustainable as it could be by searching for a way to compost their used coffee grounds. However, at the same time, there are also people on campus who occasionally get really ecstatic about composting and want to compost everything they receive at late meal, down to the utensils and plastic condiment cups.

Nevertheless, I believe that the Office of Sustainability has been doing a great job on campus in order to educate students about what they can do to live more sustainable lives. I have learned that sustainability can take many forms and may look different in different places depending on the limitations of each place. For example, some products that are marketed as compostable aren’t always easily converted into soil by our composting system and it takes time, dedication, and patience in order to ensure that every member of a community understands the limitations that may be present. All in all, I have learned lessons that I believe will be extremely beneficial in the future as I continue to integrate sustainability into my living habits and encourage others to do the same. 

We wish Milan the best of luck in her future endeavors!

Next week, we will hear from one of our long-standing team members, Wesley Wiggins ’21. Wesley will be the ComPOSTer’s resident blog writer for the next several weeks during which he will use his operational expertise to provide insightful updates on all of the exciting coursework and research happening around the project through our Campus as Lab program.

The ComPOSTer: Juneteenth Reflections

Good morning ComPOSTer subscribers,

Yesterday, July 19th, Princeton University offered all faculty and staff a fully paid day off to recognize the significance of Juneteenth – the day 155 years ago when the last enslaved African Americans in the country learned of their freedom – and to provide space to contemplate how we can all do our part to eliminate structural and overt racism and other forms of discrimination on our campus, in our communities, and in our country.

As such, this post aims to raise awareness about how waste management and the larger food system have contributed to racial injustice and how composting can be a part of the solution to achieve a more equitable society.

The sustainability movement is not complete without racial equity

Along with violence and police brutality, the food system is another, yet under-acknowledged, area in which systemic racism against Black people exist. From the allocation of farm subsidies and marketing of fast food, to the siting of waste disposal facilities, the U.S. food system has economically discriminated against Black communities while unequally exposing them to environmental harms and diet-related diseases.

According to Black food justice leaders, the solutions to eliminate food system inequities are not solely a matter of access or education, but rather that of poverty alleviation. Funneling capital into Black communities and allowing the people to own their own land and businesses will provide Black people with the financial stability and empowerment to grow and consume accessible, affordable and nutritious food.

How does composting fit into the equation?

First off, it is important to note that indigenous people and African Americans, such as early civil rights figure, George Washington Carver, knew about the importance of composting and using compost to promote sustainable agriculture practices long before the organic farming movement became popularized by the Rodale Institute in the mid-1900’s.

That point aside, composting uneaten food at a local scale not only diverts material away from landfills or incinerators (which have been disproportionally sited near low-income and minority communities), but provides a soil amendment to support community food-growing operations, while also offering other benefits such as job creation, stormwater management, and more.

Shown below is a photo of Leah Penniman (far left) leading a youth group in maintaining a compost pile at Soul Fire Farm. Leah is one of the aforementioned food justice pioneers, and co-founded Soul Fire Farm in Grafton, NY with the intent of ending racism and injustice in the food system by reconnecting people of color to the land on their own terms.

Photo credit: OMD blog

To learn more about the intersection of food and/or composting, health, and race, see below for recommended readings:

Why Food Belongs in Our Discussions of Race 

The Good Food Revolution: Growing Healthy Food, People, and Communities

Farming While Black

The ComPOSTer: SCRAPPY on the move; National Learn about Composting Day

The month of May began with a week-long celebration of International Compost Awareness Week (ICAW) and now it comes to a near end with

National Learn about Composting Day!

During ICAW, we highlighted 5 composting facts, but for a deeper dive into the benefits of composting, check out this series of infographics developed by the Institute for Local Self-Reliance.

S.C.R.A.P. Lab Updates

Phase 1 of the S.C.R.A.P. Lab facility relocation began earlier this week when “SCRAPPY” was dismantled and transported to a temporary storage location. SCRAPPY will remain there until our new permanent location is finalized and the facility is reconstructed. We will post more updates here, but in the meantime, check out a few photos from the move which took about half a day:

Dismantling the screw conveyor auger
SCRAPPY being rolled out on a wooden “sled”
Two forklifts raise the composting system onto the flatbed truck
All parts of the composting system are strapped securely to the flatbed
The flatbed arrives at the storage site and the forklifts are back to lift SCRAPPY off of the truck
SCRAPPY stored safely in the storage barn

The ComPOSTer: ICAW Recap

Hi everyone,

Thanks for celebrating International Compost Awareness Week (virtually) with us!

In case you missed some of our featured content, here were some of our favorites from last week:



The ComPOSTer – International Compost Awareness Week!

Good evening everyone,

Did you know that the first full week in May is International Compost Awareness Week (ICAW)! This year celebrates the 25th anniversary of the event which aims to increase public awareness on the benefits of compost and organics recycling.

To celebrate ICAW, we’ve made a few updates to the blog. You’ll find:

  1. A new “Resources” section that provides readers with information on how to compost at home
  2. The background story behind the S.C.R.A.P. Lab which can be found in the “About” section

Additionally, be sure to follow the Office of Sustainability’s social media accounts (tigersgogreen) this week for learning and engagement opportunities including fun videos from our staff and student EcoReps:




Happy composting!

The ComPOSTer: New Video, Gov. Signs Food Waste Bill, How to Plant a Victory Garden

Happy Friday everyone!

Today the ComPOSTer presents a few highlights and resources to bring some positivity to your day, as well as inspiration for sustainable action as we head into the weekend and Earth Week! In this post, you’ll get a virtual behind the scenes look into S.C.R.A.P. Lab operations, read an update about the NJ food waste recycling bill, and learn about a “toolshed” of resources to start your own Victory Garden (using compost, of course).


Follow the journey of campus food scraps as they travel from the kitchen in Frist Campus Center to the University’s onsite S.C.R.A.P. Lab for conversion into compost that is used to support plant growth and health on campus:


After passing in the Senate, New Jersey’s food waste recycling bill was signed into law by Governor Murphy earlier this week. Starting in 18 months, establishments in the state that generate 52 or more tons of food waste annually must arrange for separate recycling if an authorized facility is located within 25 road miles. On-site recycling is an allowable option as well. Additionally, a Food Waste Recycling Market Development Council will be established and tasked with developing recommendations for stimulating market demand for the soil amendments and energy products produced by recycling facilities. New Jersey is now the 9th US state to have some form of an organics recycling policy.


As a result of the COVID-19 pandemic, food waste losses across the country have increased significantly as US producers and growers can’t find buyers for their vegetables and dairy products. Approximately half the food grown in the US usually goes to restaurants, schools, stadiums, theme parks and cruise ships. Now that these food service operations are temporarily “closed,” vegetables are rotting in farm fields, and milk is being washed down drains. Growers are making efforts to fix the mismatch in supply and demand by donating surplus food to food banks and charities, but until more resources and partnerships are established, they are not enough to absorb the current surplus.

On the flip side, millions of Americans are now turning to “victory” gardening as a fun and productive outdoor activity to do while stuck at home.

Have you started your garden yet? If so, let us know and send some pictures by emailing

If not, you’ll gain the satisfaction of growing something yourself without having to go to the grocery store.

Here are some tips for getting started and maintaining your garden, adapted from resources provided by the U.S. Composting Council:

STEP 1: Prepare your “garden” whether that is a container garden on your balcony or patio, or a raised bed in your backyard. And remember to add compost! The foundation of growing healthy and nutritious food is healthy soil. By adding compost to your garden beds, you’ll build organic matter and provide your plants with key nutrients for healthy growth.

The difference in plant growth and health between soil with compost (right) and without compost (left)

STEP 2: Choose your seeds and plants!

STEP 3: Plant your seeds and nurture your plants through weeding, watering, and controlling pests.

STEP 4: Enjoy the harvest!

Have a question about your garden?

Contact your county’s Master Gardener representative or your state’s agriculture extension office. Link to Rutgers Master Gardener Helpline (NJ residents only).

The ComPOSTer: Status update amid COVID-19

Good afternoon everyone,

I hope this blog post finds you and those around you doing well during this difficult time.

As with many activities and events at the University, the S.C.R.A.P. Lab has closed for the remainder of the semester due to the COVID-19 restrictions. In the meantime, any food waste generated at Frist Campus Center will be picked up by our third-party organics recycler, Organic Diversion.

When S.C.R.A.P. Lab operations resume, the composting facility will no longer reside at the current location on FitzRandolph Road, but at a new site on campus. Due to Capital Planning efforts, we will be moving to a permanent location along Washington Road in May/June. Over the next weeks and months, the ComPOSTer will chronicle this journey, and will continue to provide research updates and information about all things composting and compost, so please keep reading along!

A big thank you to all of the students who assisted with composting during the ’19-’20 academic year! Pictured here: TOP from left to right: Wesley Wiggins ’21, Stanley Cho ’23, Joe Kawalec ’21; BOTTOM from left to right: Gina Talt (project manager) ’15, Reese Knopp ’23, Kiley Coates ’20

On that note and in better news – earlier this month, the NJ food waste bill that was referenced in the last blog post was passed by the Senate and currently waits to be signed by Gov. Murphy.

Under the bill, large food waste generators (e.g. establishments like prisons, hospitals, higher education institutions) will be required to source separate and recycle their food waste if they generate an average projected volume of 52 or more tons of food waste per year (i.e. 1 ton or more of food waste per week), and are located within 25 miles of an authorized food waste recycling facility.

The bill will advance the organics recycling industry in New Jersey by incentivizing the construction of either composting or food waste-to-energy facilities in the state, as well as the use of the associated soil amendments like compost for landscaping and construction projects. Read more here.


We end the academic year having composted a cumulative 91 tons of food waste since the start of the project. We look forward to continuing our journey in a few months!