The ComPOSTer: Welcome Back & Summer Recap

Happy First Day of Fall Semester Classes!

I hope everyone had a relaxing summer! The ComPOSTer will be back on a regular basis with the start of classes, but before we dive into the new academic year, check out what we were up to in the last two months:


Researchers in the Zhang Lab began their “Building Better Compost” study which involves analyzing the gas and microbial profiles along the composting process. The goal of the study is to inform baseline  performance and how it might change by alerting different parameters such as feedstock types and ratios. Stay tuned for results!

Under the guidance of Dr. Jared Wilmoth, Gabby D’Arcangelo ’21 and Calvin Rusley ’20 regularly took feedstock and gas samples along the “compost trail” from when the feedstock first enters the drum, to inside of the drum, and then when it is off-loaded as compost at the end.


I had the opportunity to take a week long compost operations training course with the U.S. Composting Council last month in Ithaca, NY at Cornell University. By engaging in a combination of hands-on activities, lectures, and field trips to different composting operations, I came away with a wealth of knowledge on composting best practices and tools that we will implement and test at the S.C.R.A.P. Lab over the coming year.

Two of the biggest things that we will test to optimize the composting process are 1) pre-mixing carbon into the totes of uneaten food that are especially soupy and 2) adding and/or substituting wood shavings with alternative carbon sources such as straw, wood chips, and soiled food serviceware.

My group’s compost pile that we built using a combination of wood chips, uneaten food, animal manure and bedding (yes you can compost manure!). Left – measuring temperature of the pile on Day 2 ; Right – Steam rising from the pile when it was dissected on the last Day (5)

Field trips to a vermi (worm) composting facility followed by a  facility that composts in 100-ft long aerated static piles.

To-Date Data 

Total Food Academic/Residential Buildings Campus Center/Cafes Wood Shavings (BA/CS) % BA/CS Compost Off-Loaded GHG Emissions Saved (MTCO2-eq)
Cumulative (lbs) 121,540 2,376 119,164 38,830 32% 110,400 36

The ComPOSTer (7/19): Introducing Our Summer Assistants + U.S.C.C. Membership!

Happy Friday everyone,

After learning about the post graduation plans of former S.C.R.A.P. Lab assistant, Helena ’19, this week we will feature profiles of the three students who are serving as operational assistants during the summer. All three are rising seniors who are on campus either to take classes or work on their senior theses:

  1. Name and Class Year: Ishanya Anthapur ’20
  2. Major: Ecology & Evolutionary Biology
  3. Hometown: San Jose, CA
  4. Why you decided to join the team: Working at the S.C.R.A.P. Lab seemed like a great way to learn about the food circulation at Princeton and to reckon with how much extra food waste we generate and what we’re doing to offset that

  1. Name and Class Year: Kiley Coates ’20
  2. Major: Geosciences
  3. Hometown: Fort Mill, SC
  4. Why you decided to join the team: Projects like the S.C.R.A.P. Lab relate heavily to my studies. As a Geosciences concentrator, I want to be able to help solve environmental issues and create a society where we live more sustainably. The S.C.R.A.P. Lab is a great step to not only reduce food waste on campus, but model how this could be applied in other settings.

  1. Name and Class Year: K. Stiefel ’20
  2. Major: Chemistry
  3. Hometown: Flemington, NJ
  4. Why you decided to join the team: For a while I’ve been interested in individual-scale composting, but I’m interested in seeing how the process is effected on larger scales as well. This is the perfect opportunity.

This summer, Princeton University became a member of the U.S. Composting Council (U.S.C.C.), a national non-profit dedicated to the development, expansion and promotion of the composting industry. The membership provides a great opportunity to stay updated on the latest advancements in compost research, policy, standards, and best management practices.

Weekly Data (7/12 – 7/18)

Our processing numbers were up slightly this week as we enter peak summer and the campus cafes start offering outdoor summer BBQs:

Total Food Academic /Residential Buildings Campus Center/Cafes Wood Shavings (BA/CS) % BA/CS Compost Off-Loaded GHG Emissions Saved (MTCO2-eq)
7/12 – 7/18 2,896 66 2,830 982 34% 3,000
Cumulative (lbs) 106,869 2,056 104,813 33,610 31% 93,000 32

The ComPOSTer (7/12): Alum profile + 100,000 lbs. milestone!

Good evening all,

This post features an update from the S.C.R.A.P Lab’s newest (and first) alum – Helena Van Brande ’19!

In between translating poems across three different languages for her senior thesis, and premiering in French theater shows among other activities, Helena worked several hours per week at the S.C.R.A.P. Lab for much of the 2018-2019 academic year and was an invaluable assistant. Although we will miss Helena here in Princeton, she has already used her composting knowledge to advance food scraps diversion efforts in her hometown and soon as a FoodCorps service member. Read more about Helena’s post-graduation plans below:

Helena after installing a Jora composter at her family’s home. 

What are your post-graduation career plans?

Helena: “I am going into a year of service with FoodCorps Americorps in Lakeview, Oregon.  I’ll be working with the local community, including the county hospital and local schools, to drive and develop different food-related educative projects. Lakeview, Oregon is a small town in South-East Oregon with a population of less than 2500. Situated in the high desert region, it’s surrounded on all sides by beautiful mountains, lakes, and national parks. I couldn’t be more excited for the opportunity to move to a place like Lakeview and help educate young people about material I am really passionate about. Although I will be in a position to educate, I have no doubt that I will be learning a lot as well.”

How did working at the S.C.R.A.P. Lab prepare and/or develop your interest in pursuing this line of work?

Helena: “Something I will bring with me as a FoodCorps service member is, of course, composting. I have truly loved the time I’ve spent working at the SCRAP Lab with Gina and the other students, even though the work would leave me smelling of rotting and half-digested food scraps for hours. Through Gina, I’ve learned a lot about the chemistry of compost and how important it is to maintain a balance of Nitrogen – Carbon material entering the system, while also keeping an eye on the kinds of food scraps that the university provides us with. Admittedly, these are often less than ideal being cooked, liquid, and/or oily. I hope that I can take some of the things I’ve learned at the SCRAP Lab and scale it down to a manageable size, maybe even institute a few worm farms.

To me, composting is one of the key ways in which we as individuals can directly influence our environment by taking food waste that would otherwise get dumped into the landfill and instead convert it into nutrient-dense soil, which we can then feed back into the earth, replenishing bacteria, microbes, bugs, and rejuvenating soil chemistry and composition. In turn, this process invigorates plant-life, which is incredibly important if we want to keep agriculture sustainable. Although gardening will certainly be a part of my job description in Lakeview, the growing season is quite short due to the high elevation. As a result, my focus will be more on food systems, nutrition, food preparation, and composting.”

We wish Helena the best of luck in her future endeavors. Next week we will feature the three new students who have joined the team for the summer.

Weekly Data (6/27 – 7/11): 100,000 lbs. milestone!

Since the project’s start 10 months ago, the S.C.R.A.P. Lab has converted over 100,000 lbs, or 50 tons, of uneaten food into compost!

Total Food Acad./Resid. Buildings Campus Center/Cafes Wood Shavings (BA/CS) % BA/CS Compost Off-Loaded GHG Emissions Saved (MTCO2-eq)
6/21 – 6/27 2,048 18 2,030 676 33% 2,000
6/28 – 7/5 2,796 38 2,758 895 32% 2,500
7/2 – 7/11 2,254 42 2212 779 35% 2,000
Cumulative (lbs) 103,973 1,990 101,983 32,628 31% 90,000 31

The Weekly ComPOSTer (6/21): More Compost Applications & Audio Journalism

Happy First Day of Summer!

This week we will feature other ways compost from the S.C.R.A.P. Lab is being applied on campus in addition to the departmental garden highlighted in last week’s post.

So what happens when compost is off-loaded from the composting system?

Twice a week after the S.C.R.A.P. lab team rakes off-loaded compost into a trailer bed, our Grounds crew hooks the trailer bed to a truck and transports it to a stockpile yard just south of main campus where the compost is dumped into its own outdoor pile covered with a tarp to prevent nutrient leaching.

Periodically, the Grounds crew will draw compost from the pile and blend it with leaves, soil and other compost generated from the campus. When lab tests indicate that this combined or “blended” product reaches a certain maturity index level, the Grounds crew will use it in one of three ways as a soil amendment on campus:

  1. Mixed into planting mediums during transplantation
  2. Top-dressed on campus lawns after aeration and before overseeding to break up soil that becomes compacted over the year due to foot and vehicular traffic. Aerating soils by perforating it with small holes and then spreading compost allows for better water, oxygen, and nutrient flow to plant roots.
  3. Used to make compost tea: a small amount of compost will be placed in a large mesh “tea” bag which is then steeped in water and aerated in a container to create a brewed, water extract of compost. The process extracts the full diversity of beneficial microorganisms from the compost (plus more if additional ingredients are added), and when applied to soils and plants, it can assist in better plant production, soil structure, nutrient cycling, and less disease incidence. It’s like kombucha but for plants* More on this later!

All of this information plus more can be heard in an audio-journalism piece that was nicely composed by graduating senior, Angela Mao ’19. For her final class project, Angela captures a sound journey from food scrap to compost. Hear it here:*

*Clarification Notes:

    • Kombucha is a fermented product while compost tea is not, but both share the benefits of introducing beneficial bacteria and in turn supporting healthy “immune” systems– whether in humans or plants
    • The term “compost” is sometimes referred in the piece as the uneaten food that is collected in the dining venues. This is a common misinterpretation of the word. Compost is what is produced after the uneaten food and a carbon source undergo aerobic decomposition.
    • The correct identification of the processing capacity of the FOR Solutions Model 1000 Composting System is “up to 5,000 lbs. of food per week,” rather than “5,000 lbs. at a time.”

Weekly Data: 5/31 – 6/20

As we enter into summer mode with our dining venues on a reduced hours schedule, the total weekly amount of uneaten food processed at the S.C.R.A.P. Lab is about 60% of that during the academic semester.

WEEK Total Food Campus Center & Cafes Academic /Residential Buildings/Events* Wood Shavings (BA/CS) % BA/CS Compost Off-Loaded GHG Emissions Saved (MTCO2-eq)
5/31 – 6/6 2,222 2,160 62 642 29% 2,000
6/7 – 6/13 2,232 2,101 131 772 35% 2,000
6/14 – 6/20 2,375 2,302 73 818 34% 2,000
Cumulative (lbs) 96,875 94,983 1,892 30,278 31%* 83,500 29

* Included in these totals is about 125 lbs. of uneaten food that was recovered from two events on campus

Thanks to all of the friends and alums who came to the S.C.R.A.P.  Lab Reunions tour on the 31st!

The Weekly ComPOSTer (6/7): Compost Applications & Clarification

Happy Friday!

We have an update on how compost from the S.C.R.A.P. Lab is being applied on campus. This week’s update comes from Luiza Wainer and Peter Green who received some of the first batch of compost from 2019 for use in a new community garden for their department. When it came time to apply the compost in their raised bed this spring, they decided to do an experiment  – they split the garden in half and applied compost to one side and not the other. Can you guess which tomato plant in the below picture received the compost application?

Answer: The tomato plant on the right! Although the two plants were planted at the same time, the soil that received compost benefited from the microorganisms and additional nutrients that have supported plant growth and health in the form of a taller and greener plant.

More application updates to come!

Lastly, this post will end with a quick clarification on last week’s mention about the relationship between compost and humus. To clarify: compost and humus are not exactly the same form of matter.

Compost generally refers to a stabilized state of the controlled aerobic decomposition of organic matter when the individual parts of the organic matter are no longer recognizable. It typically occurs outside of the soil system. This is the product that we use as a soil amendment. However compost is technically not completely decomposed as all of the microorganisms are still present and are continuing to decompose the remaining material.

Humus, which is created in the soil system, is found when the decomposition process is fully completed and all of the usable nutrients have been extracted by microorganisms, a process which takes many years.

Weekly Data: 5/24 – 5/30

The S.C.R.A.P. Lab processed less uneaten food over “Dead Week” on campus due to Memorial Day and as most undergraduates left campus for the summer. However, the volume started to increase again on the last day of the loading week with the start of Princeton University’s Reunions weekend.

Total Food Campus Center/Cafes Academic /Residential Buildings Wood Shavings (BA/CS) % BA/CS Compost Off-Loaded GHG Emissions Saved (MTCO2-eq)
5/24 – 5/30 2,164 2,126 38 685 32% 2,000
Cumulative (lbs) 90,049 87,680 1,626 28,046 31% 77,500 27

The Weekly ComPOSTer (5/29): National Learn About Composting Day

Did you know that May 29th is National Learn About Composting Day?

In its honor, this blog post will provide a brief account of composting throughout U.S. history.

In general terms, composting refers to a natural process in which organic matter is biologically reduced into a soil-building substance.

While the above definition doesn’t imply any human intervention, composting can also be more narrowly defined as a process in which we (humans) transform organic material into a soil amendment to create a beneficial growing environment for our lawns or gardens.

This second definition was “discovered” by ancient civilizations when the earliest people learned how to use organic matter, most likely in the form of manure, to enhance crop production. Ever since, the composting process has been practiced and adapted along the way by different cultures over time.

In the Americas, indigenous people used  organic matter such as buried fish and seaweed in corn planting and taught these practices to European colonists to help them grow food in the poor soils of New England.

Presidents George Washington and Thomas Jefferson were compost proponents in farm operations and benefited from the knowledge and skills of their enslaved workers.

However such a strong tradition gradually fell out of practice, starting with the westward expansion into already fertile prairie soils of the Midwest, and then the introduction of chemical agriculture. Farmers were able to achieve high yield rates without  having to invest in soil-building practices. Over time these consequences included the Dust Bowl of the 1930s and the current aquatic dead zones due to nutrient run-off.

Fortunately, the organic farming movement that includes practices such as composting to control erosion and retain and provide nutrients to plants, is making a comeback. Ever since Rachel Carson helped spark the environmental movement in the 1960s, farmers and consumers have become more aware of the environmental and health consequences of chemical farming. Today, composting is also becoming a growing solution to the municipal solid waste challenge, and a lot of research is being conducted to investigate compost’s role in mitigating climate change through carbon sequestration.

Source/Learn more: The Rodale Book of Composting: Simple Methods to Improve your Soil, Recycle Waste, Grow Healthier Plants, and Create an Earth-Friendly Garden

Weekly Data: End of Spring Semester

We saw a gradual decrease in the amount of uneaten food processed in the composting system over the last three weeks as the academic year came to a close with students finishing their papers and final exams and eventually leaving campus.

The S.C.R.AP. Lab will continue to be operational over the summer. While we will lose some of our academic/residential partners during this time, we will continue to receive a steady, but reduced, stream of uneaten food from the Frist Campus Center and Cafes.

WEEK Total Food Campus Center & Cafes Academic /Residential Buildings Wood Shavings (BA/CS) % BA/CS Compost Off-Loaded GHG Emissions Saved (MTCO2-eq)
5/3 – 5/9 3,567 3,401 166 1,099 31% 3,500
5/10 – 5/16 3,340 3,134 206 1,033 31% 3,000
5/17 – 5/23 3,149 3,022 127 1,067 34% 3,000
Cumulative (lbs) 87,885 86,792 1,591 27,361 31%* 75,500 26

*In addition to the wood shavings, we also diverted and processed 85 pizza boxes over the semester as a supplemental source of carbon

The Weekly ComPOSTer (5/10): Exciting Research Plans!

Good afternoon from the S.C.R.A.P. Lab!

The big news this week was the announcement of two research projects involving the S.C.R.A.P. Lab that were awarded Dean for Research Innovation Funds for the Campus as a Lab.

Adapted abstracts of the two projects that will start this summer are below:

Building better compost

Xinning Zhang, assistant professor of geosciences and the Princeton Environmental Institute, will lead undergraduate research that will explore conditions for creating high-quality compost that is high in nutrients and low in greenhouse gas emissions. The team will test various proportions of food waste, carbon inputs and air as well as operating conditions to identify conditions that create compost with superior levels of nutrients while reducing the natural emission of greenhouse gases due to biodegradation of compostable materials. The team will also explore the use of waste cardboard and other feedstocks from the campus to replace the current wood shavings.

Farming on campus lands

A project led by Daniel Rubenstein, the Class of 1877 Professor of Zoology, a professor in the Department of Ecology and Evolutionary Biology, and director of the Princeton Environmental Institute’s certificate Program in Environmental Studies, and Gina Talt, food systems project specialist with the Office of Sustainability — will explore how to improve Princeton’s farmland stewardship practices in ways that encourage sustainability while improving agricultural yield. Princeton University enables local farmers to raise crops on large portions of its land, but in recent years farmers have reported finding it hard to make a profit due to crop consumption by deer. Additionally, years of growing monoculture crops with herbicides and fertilizers have led to nutrient-deficient soils and a system reliant on fossil-fuel-based inputs to suppress weeds.

The project will involve undergraduates in examining the cost-effectiveness of fencing the lands to keep out deer while also exploring a variety of soil enriching and anti-weed control methods. The team will grow field corn in one-acre test plots, including fenced and non-fenced areas, to compare how farming practices affect crop growth, soil health and farmland profitability. The sustainable practices to be tested include applying compost and compost teas made from campus food scraps, planting cover crops during the off-season, and weeding with equipment rather than applying herbicides.

Read the original article on the Princeton homepage here:

Weekly Data: 4/26 – 5/2


Total Food Campus Center/Cafes Academic /Residential Buildings


Wood shavings (BA/CS)  %
Compost Off-loaded GHG Emissions  Saved (MTCO2eq)
Week Totals (lbs.) 3,214 2,972 242 1,035 32% 3,000
CUMULATIVE (lbs) 77,829 76,736 1,092 24,162 31% 66,000 23


The Weekly ComPOSTer (5/3): EQuad Cafe Pilot

Happy Friday!

Although this week might have been the last week of classes, there is still a lot happening around the S.C.R.A.P. Lab as we started a 2-week pilot food scraps and compostable service-ware effort at the EQuad Cafe.

This week, staff and volunteers from Campus Dining, Building Services, and the School of Engineering and Applied Sciences monitored the bucket dedicated to compostables and educated diners at the cafe about the effort. Key findings so far include:

  1. Most people were very receptive to the idea of composting and took time to stop and and look at the signage and information on the LCDs.
  2. The team received insights into consumer disposal behavior and how to better position the compostable bin in the cafe in order to attract people and divert material.
  3. Similar to other events, napkins and the food service-ware (World Centric plant fiber clamshells and Chinet plates) made up the majority of the contents of the compostables bucket

In Week 2 of the EQuad Cafe Pilot, there will be no bin monitoring and education. We will evaluate how well prior messaging/education as well as the continued signage impact usage and contamination rates (unfortunately other items offered at the cafe such as utensils, soup containers, and coffee cups are not compostable in our composting system due to the greater thickness of their respectable materials and the need for higher decomposition temperatures).

Check back for our findings!

Weekly Data: 4/19 – 4/25

Last week we processed 3,454 lbs. of uneaten food, 188 lbs. of which came from our satellite locations in the academic/residential buildings which is an all time high as diversion awareness continues.

Total Food Campus Center/Cafes Academic/Residential Buildings


Wood shavings (BA/CS)


Compost Off-loaded GHG Emissions Saved (MTCO2eq)
Week Totals (lbs.) 3,454 3,266 188 1,054 31% 3,500
CUMULATIVE (lbs) 74,615 73,764 850 23,127 31% 63,000 22

The Weekly ComPOSTer (4/24): Sustainability Action Plan; More Materials Testing

Happy belated Earth Day from the S.C.R.A.P. Lab!

The S.C.R.A.P. Lab represents one way in which students and staff from across campus can partner on a daily basis to reduce waste and promote a circular economy on campus through a “table to soil” approach. Pictured above is just a handful of those involved in the project.

In bigger news, Princeton University’s Office of Sustainability released its new Sustainability Action Plan on Earth Day which sets bold targets and outlines innovative strategies to engage all faculty, staff and students in creating a sustainable campus and future toward 2026 and beyond.

In addition to a target for net zero greenhouse gas emissions by 2046 — the University’s 300th anniversary — the Plan calls for six other action areas including an aim to cultivate healthy and resilient habitats and achieve zero waste by reducing waste and expanding sustainable purchasing.

The S.C.R.A.P. Lab is one strategy that can simultaneously move the campus toward zero waste and healthier and more resilient habitats by…

  1. Advancing evidence-based sustainable landscape management solutions. The S.C.R.A.P. Lab will strengthen and further support studies by faculty, staff, and students on how to use compost and compost tea to reduce the University’s reliance on fossil-fuel based landscape inputs to control disease and pests.
  2. Providing an outlet for increased food scraps collection across campus to locations other than major dining venues. If done strategically, expanded food scraps collection would not only reduce landfill waste, but the number of loads of recyclable material that are rejected at the MRF (materials recycling facility) due to items coated with food residue.
  3. Advancing evidence-based sustainable purchasing solutions by studying the compostability of different food service ware so that the items that the campus buys can be tied to compostable products whenever possible. We’ve had some successes so far on a smaller scale with World Centric plant fiber clamshells, and the Huhtamaki ‘Chinet’ plate, so we have initiated efforts to test larger loads of these products, starting with last week’s effort to collect the Chinet plates (made from molded recycled paper) after Frist Late Meal (see below).

[Pictured at left: Members of the sustainability group, Greening Dining, helped students correctly sort their unused items during Late Meal. All food scraps and Chinet plates were captured and sent to the S.C.R.A.P. Lab for processing  the next day (Pictured at right)]

Stay tuned for results!

Weekly Data: 4/12 – 4/18

Total Food Campus Center/Cafes  

Academic/Residential Buildings



Wood shavings (BA/CS)


Compost Off-loaded GHG Emissions Saved (MTCO2eq)
Week Totals (lbs.) 3,089 2,954 135 1,011 33% 2,000
CUMULATIVE (lbs) 71,161 70,498 662 22,073 31% 59,500 21

The Weekly ComPOSTer (4/17): Coffee Club Partnership!

Good evening,

This week’s ComPOSTer welcomes Princeton’s newest coffee shop, the Coffee Club, to our growing list of partnering venues!

Located in the taproom of Campus Club, the Coffee Club held its grand opening on April 14th and is run and staffed entirely by students.

With sustainability being one of its core values, collecting coffee grounds for composting at the S.C.R.A.P. lab  is now one of the Coffee Club’s initiatives to promote more environmental and socio-economic  practices. Additionally, the club also sources pastries and roasted coffee beans from local vendors, and is committed to maintaining affordable — if not the lowest — coffee prices both in and off campus to foster an inclusive environment.

In just under 2 days, the Coffee Club has produced 25 lbs. of coffee grounds, which will provide nitrogen-rich material to our feedstock, and a good source of energy for the microbes that convert the organic matter to compost.

Fun fact: Contrary to belief, coffee grounds will NOT lower pH and make compost more acidic.  While fresh coffee grounds may be acidic, once brewed, they are closer to pH neutral. Since acid is water-soluble, any acid in the beans would have already leached into your cup of Joe.


Weekly Data: 4/5 – 4/11

Total Food Campus Center/Cafes  

Academic/Residential Buildings



Wood shavings (BA/CS)


Compost Off-loaded GHG Emissions Saved (MTCO2eq)
Week Totals (lbs.) 2,697 2,589 108 928 34% 2,000
CUMULATIVE (lbs) 68,072 67,545 527 21,062 31% 57,500 20