ICAW 2022: Facility Updates

Happy International Compost Awareness Week!

Our first celebratory post is an update on the status of the composting facility.

The facility has passed all inspections – building, electric, plumbing – and we are currently working on preparing SCRAPPY and the facility to restart operations.

Check out the improvements we have made to the composting system based on lessons learned from our first 1.5 years of operation:

Screener Upgrades:

To prevent the build-up of compost inside of the off-loading screener and to improve the rate at which compost is off-loaded from the composting system, we’ve installed a screener with more openings and with larger access doors

Old screener with the end panel having smaller access doors and no openings
New screener with larger access doors and mesh wire openings on the end panel

HOPPER Upgrade:

Because we process bulkier and solid items (e.g. large watermelon rinds), we have installed a wider and stronger agitator mechanism to facilitate the movement of food to the shredder below.

Old agitator with two narrow flaps
New agitator with one, but wider and more durable flap that covers the entire width of the hopper

Thanks for reading!

Stay tuned for the next two posts on solutions for home composting!

ICAW 2022 Preview: Recipe for Regeneration

Next week, May 1 – 7, is International Compost Awareness Week (ICAW)!

Just as a chef pulls together the best ingredients to create the perfect recipe, the 2022 theme, Recipe for Regeneration: Compost, focuses on the crucial role recycling our food scraps and yard trimmings plays by creating compost, which when added to soil results in a recipe that makes our food more nutritious, the air we breathe cleaner, and our climate healthier overall.

With Earth Month just wrapping up and in honor of ICAW, the ComPOSTer will post several times during the week. Stay tuned for the following content:

  • SCRAPPY Updates
  • Composting in the Forbes Garden
  • Composting at Home Q&A with Ted Borer
  • Why is Soil Biodiversity Important?

Lights, Camera, Action (soon)!

A quick update to say that we officially have power at our new location!

Successful energization of the composting facility – lights, exhaust vent, heaters, and composting system
A view of the back of the facility and wood shed
Wood shed
Inside of wood shed which also has lighting

Big Goals for 2022!

Dear friends of the S.C.R.A.P. Lab,

We hope all forty-two of you are continuing to stay healthy and are enjoying a great start to 2022 ! As with every first post of a new year and new semester, the ComPOSTer takes a moment to recap the past year and more importantly, provide some optimism about what is to come in the year ahead.

Our year started off on a high note, beginning with a tour of the new facility to a group of graduate students and staff during Princeton’s Wintersession. Pictured above: Gina Talt ’15 explaining the University’s wasted food diversion program


Unfortunately our original plan to relocate and re-open the S.C.R.A.P. Lab during the spring of 2021 was halted due to permitting challenges. While the relocation was delayed to early September, progress was swift, and the entire facility and composting system were reassembled in November. In the meantime, the ComPOSTer completed its faculty Q&A blog series with the graduation of Wesley Wiggins ’21 and covered other news about legislative updates on the state of organics recycling in New Jersey, and world news such as The Global Methane Pledge.

Additionally, we have made good use of the pause in operations by getting more involved in community partnerships in food and agriculture research, understanding how environmental justice factors into these issues, deepening our operations training, networking with other system operators and industry experts, and developing a re-start plan that includes practical tweaks to the facility and equipment that will help make operations easier. 

More new site progress! The exterior design and construction is now complete with the Shelter Cover shed on the right and concrete pad connecting it to the main facility

2022 PLANS

The last remaining  step before we can restart operations is the electrical hookup. We are hopeful students will once again have a hand in operations this semester. Then we are planning to pick-up where we started on our operational and research efforts, including:

  • Making improvements to our composting equipment to better meet our needs
  • On-boarding an assistant operational manager
  • Continuing to test and expand compostable serviceware options in the Frist Gallery
  • Integration of research efforts with operational testing of different feedstocks and recipes (i.e. to what extent can we substitute our purchased wood shavings for wood chips, leaves, or even compostable serviceware, the latter of which looks like it could be here to stay? What is the impact on emissions, microbial communities, nutrient density, etc.)?
  • Testing of new food scraps collection and drop-off systems to expand reach across campus. Now with our own van!
  • Launching new graphics and informational signage for the relocated facility
  • Using Tableau Public to better visualize and communicate our composting data
  • Continuing to raise awareness about the environmental justice implications of composting
  • Seeking new avenues of academic engagement (currently helping to plan a first-year seminar course)

Stay tuned for a notice about a re-launch ceremony when composting officially begins, similar to our ribbon-cutting event in 2018

New facility photos and Congress briefing on “forever chemicals”

Progress at 300 Washington Rd.

New updates include the installation of an exhaust fan (back of the facility) and the pouring of the concrete pad for the adjacent wood shed

Concrete pad for the foundation of the wood shed that will store the carbon feedstocks for composting operations. A smaller “hoop” structure will cover the footprint

Jaffé briefs Congress on “forever chemicals”

Peter Jaffé
William L. Knapp ’47 Professor of Civil Engineering
Professor of Civil and Environmental Engineering

Meanwhile… Testifying before Congress, Professor Peter Jaffé called on the federal government to support research into and mitigation of chemicals called PFAS, or “forever chemicals” because of the time they take to break down in the environment. Earlier this year, the ComPOSTer interviewed Dr. Jaffé about his research to mitigate PFAS contamination and to remove the chemical from groundwater and the environment. Dr. Jaffé recommended that Congress direct more funding into research on the forever chemicals, arguing that a better understanding of their impacts will help with mitigation.

Read more about Dr. Jaffe’s testimony and find the full briefing here: https://engineering.princeton.edu/news/2021/12/09/jaffe-briefs-congress-forever-chemicals

In Context: PFAS & Compost

In a recent BioCycle column, Dr. Sally Brown shows how the biggest risk of exposure to PFAS comes from direct exposure pathways to dust, cosmetics, cookware and packaging (including the food that touches both). As a result, PFAS ends up inn compost but concentrations are much lower than those in many household products. Dr. Brown argues that the manufacturing of products with PFAS should be restricted to prevent the direct exposure to these chemicals, instead of restrictions being placed on down-stream sources of PFAS like compost. The compostable food packaging industry is currently testing and developing viable alternatives that don’t include PFAS so these chemicals don’t end up in composts in the first place. However they are currently not widely available or in limited supply.

2-yr old compost, new design features and other reconstruction updates!

This month we’ve made significant progress on the reconstruction of the composting facility. Check out the photo essay below to see and hear about several new and exciting design and infrastructure improvements (and some well-aged compost)!

Pictured above: The new site on a crisp fall morning.
Foreground: On-going landscape grading work
Background: The outline and beginning construction of a covered storage space for our carbon source, and behind that the electric equipment for the facility
The composting system was completely reassembled last week. The digestion vessel and loading hopper are now stationed on top of elevated slabs which will allow our receiving receptacle trailer to fit completely under the screener on the off-loading end. Next up: Cleaning all the debris and dust accumulated in almost 2 years of storage
Nearly 2-year old compost!
This compost “brick” was found inside of the composting system . Because of the emergency shutdown during spring 2020, some of the food scraps and wood shavings remained, and they ended up naturally decomposing

More updates to come in December. We are getting closer to a “power on” date and hope to resume composting operations in January of the New Year.

Have a happy and healthy Thanksgiving holiday!

Relocation Update, Webinar & More

In this ComPOSTer, we provide an update on our facility relocation and highlight an interesting upcoming webinar on Wasted Food Solutions and more composting-related current events.

SCRAPPY on the move

Efforts are underway to move the composting system into the reconstructed facility. Pictured above is a forklift transporting “SCRAPPY” from its storage location to the facility where it will be placed on the elevated slab below

Wasted Food Solutions Webinar

Join this virtual workshop co-hosted by the Center for EcoTechnology (CET) and New Jersey Composting Council (NJCC) to learn about strategies for implementing wasted food prevention, donation, and diversion programs in businesses in the food service sector. Although specific to New Jersey and its Food Waste Law, participants will leave with an understanding of the next steps for building wasted food management into their operations and gain access to digital resources and guidance documents. All attendees will also have access to free one-on-one support from CET, which will take place in the last hour of the workshop.


In the News

The Global Methane Pledge was introduced recently as an ambitious plan to slash global methane emissions 30 percent by 2030.

The pledge is a big step for limiting the potent greenhouse gas, but critics are quick to point out that the pledge fails to address limiting emissions from the largest source of methane globally — agriculture.

  • The pledge only promises to incentivize “the deployment of improved manure management systems, anaerobic digesters, new livestock feeds, composting, and other practices.”
  • In the U.S., the Biden administration plans to pose direct restrictions on the oil and gas industry, but only voluntary adoption measures with the agriculture sector.
  • Meanwhile, environmental justice groups believe the solution lies in transitioning away from the large-scale livestock operations that are one of the biggest contributors of methane emissions. These facilities dump manure into large “lagoons” which creates unsafe air and groundwater in the disproportionately Black, Latino, Indigenous, and white rural surrounding communities.

As an alternative solution, New Jersey Senator Cory Booker reintroduced the Farm System Reform Act, which imposes a moratorium on these industrial facilities and creates federal financial assistance for farmers to transition to pasture-based dairy and hog farming. 

Read more: There’s a major gap in the new methane pledge: Agriculture

NOTE: If managed properly, grass-fed animal operations can be a more sustainable option and healthier to nearby communities, however the scientific community is still in debate over whether pasture-raised systems (in particular beef), are consistently more climate-friendly than industrial beef.

First Photos of New Location

In today’s update we bring the first photos of the S.C.R.A.P. Lab as it is being reconstructed!

Check out the photo essay below from the construction site:

Driveway leading to the S.C.R.A.P. Lab. The fabric structure has been placed over the dried slab
Front of the building
Inside: The first fabric layer without insulation, exposing the scaffolding. Installation of electric conduit has begun
View from the back: To the left of the composting facility where the soil is currently disturbed will eventually be a small shelter cover shed for storing our carbon feedstock

The ComPOSTer: Fall Semester Update

Welcome back to campus for the new academic year!

It is great to see everyone back again while continuing measures to prevent the spread of covid.

This summer we received our municipal permit to begin the reconstruction of our composting facility on Washington Rd near Princeton’s solar field (see circled area on the map below)

This week the concrete was poured to create the slab and by mid-September the fabric structure will be re-erected and then we will reassemble the composting system inside (more updates and pictures to come). The operational restart is still tentative but will happen sometime this semester, likely in mid/late October.

In other composting news:

  • New Jersey’s food waste diversion legislation, will go into effect this October. The bill mandates establishments (e.g. hospitals, prisons, schools, restaurants, supermarkets) 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. It will also create a market development council to assist in generating demand and finding markets for finished compost.
  • At the national level, H.R. 4443 COMPOST Act was recently introduced in Congress to provide critical infrastructure and financial support for the composting industry.  As currently written, this legislation has three main goals:
    • Establish a USDA-led grant and loan guarantee program to provide $200 million in funding per year through 2030 for compost equipment, siting, and systems needed to expand compost facilities accepting food scraps, both public and private.
    • Provide funding for collection programs and development of markets for finished compost
    • Recognize compost as a conservation practice which will make compost use an eligible reimbursement item for farmers who use compost to improve soil and sequester carbon.

The ComPOSTer will continue to follow and provide updates on these and other related legislation.

Th ComPOSTer: Interview with Professor Xinning Zhang

Our faculty Q&A series wraps up with an update from Professor Xinning Zhang, an environmental microbiologist jointly appointed in the Department of Geosciences and the High Meadows Environmental Institute. This month, the ComPOSTer interviewed Dr. Zhang to learn more about how her lab is extending its research in microbial metabolism and biogeochemcical cycling on the Princeton campus, and how it relates to environmental justice.

Xinning Zhang, Assistant Professor of Geosciences and at the Princeton Environmental Institute
Professor Xinning Zhang; Photo from Princeton University Dept. of Geosciences

What are the main questions that your research group is asking about the composting process and how is the S.C.R.A.P. lab involved?

The Zhang lab is broadly interested in understanding the role of microbes in decomposition and greenhouse gas cycling within man-made and natural environments.  As the environmental and human health harms of using industrial fertilizers to promote plant growth have become clear, many communities, including the University and the township, are exploring compost as a nutrient rich amendment to soils in place of industrial fertilizers.

Working with the S.C.R.A.P. lab, members of the Zhang group (Gabrielle D’Arcangelo ’21, Galen Cadley ’21, Dr. Jared Wilmoth) have been studying the microbial decomposition of food and garden waste into compost and greenhouse gases like carbon dioxide and methane with the aim of optimizing Princeton University’s aerobic digester for producing nutrient rich compost with low net greenhouse gas emissions. Specifically, we would like to determine (a) who the main microbial actors are in the compositing process, (b) how these microbes work together to make healthy compost, and (c) how microbes and their activities respond to changes in the composition of incoming food waste flows and environmental characteristics like aeration levels and temperature.

Gabby D’Arcangelo ’21 and Calvin Rusley ’20 during the summer of 2019 collecting feedstock samples from the composter for microbial rDNA sequencing

What have been the preliminary findings to-date and the next steps in the research?

While there is insufficient sample consistency to make any firm conclusions, preliminary findings of the microbial community analysis have identified Lactobacillus and Acetobacter to be the most dominant bacterial groups (indicating a rapid uptake of simple sugars), followed by Clostridium and Chitonophaga (complex carbon degradation), and less than 1% of methane-producing organisms, the most dominant being the oxygen-intolerant hydrogen gas consumer, Methanobacterium.

An accumulation of the latter category or “methanogens” was found during a power outage and when on-loading/off-loading of material was halted. These results indicate that to avoid increased methane emissions, compost materials should not be allowed to sit for long durations (> a couple days) in the composter, particularly in the back end of the unit where oxygen-free conditions favoring microbial methane production easily develop.

Future work will aim at evaluating whether increases in aeration frequency and/or changes in food waste/bulking agent composition will further reduce composter methane levels. However it is important to note that even optimally working municipal waste composts can contain anaerobic pockets allowing the presence of about 1% methane-producing bacterial species, so these results are consistent with those found in other composting operations.

Why is this research important and how does it relate to environmental justice?

The application of industrial fertilizers leads to numerous environmental problems, most notably the eutrophication of water supplies with detrimental effects on water quality, fisheries health, and greenhouse gas emissions. Unfortunately, these environmental harms are disproportionately borne by people of color in lower income neighborhoods. We hope that our work with the S.C.R.A.P. lab on the science behind composting will aid in weaning our food and landscaping system off industrial fertilizers to promote environmental health and justice.

Interview edited for length and clarity