Hello fellow compost aficionados!

Apologizes for the overdue blog post! We’ve been busy preparing for several  new efforts in between continuing our compost operations. Check out the exciting new partnerships and initiatives that will start later this week:

• Compost Concierge Pilot : We’ve been working with grad students and departmental managers to begin a pilot food scraps collection program in three academic departments (Mechanical & Aerospace Engineering, Geosciences, Ecology & Evolutionary Biology). The food scraps, collected in 5-gal bins, will be picked up twice weekly by the operational team and dropped off at our composting facility.
• Composting at Tiger Sustainability Night (2/22): We will be partnering with Campus Dining and EcoReps Greening Athletics to recover food scraps at our first major event – double-header basketball games against Cornell at 5:30pm and 7:30pm at Jadwin Gym on Friday, February 22. Watch the promo video featuring Lexi Weger ’22 and Gabrielle Rush ’19

• Lastly, this week we will be finalizing a new name for the project to  better reflect that the biodigester is a composting system that decomposes food scraps into compost aerobically (with oxygen), not a digester,  which generally refers to systems that break down organic waste anaerobically (i.e. without oxygen) and produce digestate, which is similar to, but technically not the same as compost. We will unveil the new name next week!

Weekly Data: 2/4 – 2/15

Now that the spring semester is in full swing, our  weekly food scraps volume is starting to creep back up again, closer to the 3,000 lbs./week range. We are also experimenting with a higher percentage (by weight) of wood shavings to food scraps, increasing slightly from 30% to 33%.

	Food	Wood shavings (BA/CS)	% BA/CS	Compost Off-loaded
Week of 2/4 (lbs.)	2,679	875	33%	2,500
Week of 2/11 (lbs.)	2,997	985	33%	2,750
CUMULATIVE (lbs.)	49,302	14,913	30%	38,500

This week we welcome another project partner to our growing list of composting venues: the McGraw Center for Teaching & Learning!

Like the Scully Co-op, the McGraw Center will collect any food scraps generated in its office in a 5-gal bucket for weekly pick-ups.  The effort will be spearheaded by the McGraw Center’s Manager Sandra Moskovitz, a sustainability ambassador who has been composting herself for 30 years.

Almost five years ago, the Office of Sustainability interviewed Moskovitz for a staff profile. When asked, “How could the University become even more sustainable? she replied:

“My number one wish is for a campus wide composting program, it saddens me to see the waste around campus that could so easily be composted—miles of pizza boxes, tons of used paper towels and paper plates, not to mention the pounds of food scraps that are thrown away in offices and classrooms each day. I know that this is something that is being discussed, so I hope that a program will be in place soon. It will make a huge difference in reducing the amount of waste that the University’s population makes every day.”

Thanks to outspoken people like Moskovitz, the University now has an on-site composting system that will continue to support expanded food scraps diversion efforts while contributing to an ethos of sustainability where organics recycling will ultimately become the norm on campus.

To realize this goal, we plan to partner further with Moskovitz and the McGraw Center around green office strategies so that all of their events are zero-waste, and to share these best practices across campus.

Weekly Data: 1/28 – 2/1

The lower volume of weekly food scraps continued into the last week of January as finals wrapped up and led into Intersession (a 1-week break before the start of the spring semester).

	Food	Wood shavings (BA/CS)	% BA/CS	Compost Off-loaded
Week Totals (lbs.)	2,504	776	31%	2,000
CUMULATIVE (lbs)	43,626	13,053	30%	33,250

With campus cafes closed on Monday (1/21) in observance of Martin Luther King Jr. Day,  we only loaded  2,238 lbs. of food scraps into the composting system last week, or about 40% less than the average weekly amount.

We did not detect any visible pieces of recently tested bioware in the 2,000 lbs. of off-loaded compost. These results are promising, but we will wait for this week’s batch of compost to know for sure just in case the material didn’t fully migrate to the end of the vessel.

Weekly Data: 1/21 – 1/25

	Food	Wood shavings (BA/CS)	% BA/CS	Compost Off-loaded
Week Totals (lbs.)	2,238	706	32%	2,000
CUMULATIVE (lbs)	41,122	12,277	30%	31,250

First Off-Loading of 2019 & Bioware Testing!

We had an exciting first full week operating the biodigester in 2019. Highlights included our first off-loading session as the vessel neared its capacity, and materials testing to help inform our Campus Dining team about types of food service ware that may be composted in our system versus sent to the landfill.

[Composted off-loaded on January 18th]

Henry Wietfeldt ’22 drops one of 50 palm plates into the loading hopper to be shredded before it enters into the rotation vessel. We also tested World Centric plant fiber clamshells, and the Huhtamaki ‘Chinet’ plate. In about a week or so we will be able to tell how well each of the items broke down in the system based on their presence (or lack thereof) in the finished compost.

Click here to watch as shredded pieces of Chinet plates fall from the auger into the input port.

Weekly Data: 1/14 – 1/18

We processed just under 3,000 lbs. of food scraps last week, which is lower than the average of about 3,500 lbs. for a full week. Composting is a great way to return nutrients to the environment to enrich soils and grow healthy plants, but ultimately we want to reduce the amount of food (especially leftover food) from compost whenever we can, so the reduced weight from our campus center and cafes is a win and a metric we will continuously track!

	Food	Wood shavings (BA/CS)	% BA/CS	Compost Off-loaded
Week Totals (lbs.)	2,986	950	32%	1,250
CUMULATIVE (lbs)	38,884	11,571	30%	29,250

Welcome to the first weekly bioDIGESTEer of 2019!

In our first (partial) week back in operation since Winter Break, we loaded 2,346 lbs. of food scraps and 727 lbs. of wood shavings into the biodigester, thus maintaining the approximate 3:1 ratio of food to wood given the moisture content of the food scraps.

We didn’t off-load any compost because the vessel was nearly empty after having off-loaded the majority of the compost from the system before Winter Break. It will take about 2 weeks from the first loading session of the New Year on January 7th until we off-load the first batch of compost in 2019 (i.e. when the vessel drum is about 75% full).

Weekly Data: 1/7 – 1/11

	Food	Wood shavings (BA/CS)	% BA/CS	Compost Off-loaded
Week Totals (lbs.)	2,346	727	31%	0
CUMULATIVE (lbs)	35,898	10,621	30%	28,000

 

 

Thank you to all who came out yesterday to celebrate the official unveiling of the Princeton University Biodigester Project with us.

If you were unable to attend, see below for several links to media coverage around the event:

Princeton University shows off their ‘Biodigester,’ which turns food scraps into compost in 5 days (Nj.com)

TV clip (6ABC Philadelphia)

Princeton University’s new biodigester makes food scraps sustainable (Princeton University)

Happy New Year!

To begin 2019, please join us next Tuesday, January 8th, for a celebratory ribbon-cutting ceremony to formally introduce the Princeton University biodigester initiative to the greater community.

See below for additional event details. Hope to see you there!

With Winter Break in full swing, and the holidays and New Year around the corner, we present a year in review recap of the biodigester project

TIMELINE

• December 20, 2017: The FOR Solutions Model 1000 Composting System is delivered to campus. 
• April 2018: Installation Acceptance Test completed to insure the correct electrical set-up and proper rotation of the biodigester’s mechanical systems
• May 2018: Arrival and waterproofing of lifter and other operational items
• July 2018: System receives UL Certification
• September 2018: Electric inspection and town code inspections completed
• September 18, 2018: Biodigester becomes operational with the first loading of food scraps from Frist Campus Center and campus cafes
• December 2018: Project expands to include food scraps from Scully Co-op
• December 14, 2018: Last system loading of 2018
• December 20, 2018: Last off-loading of compost of 2018

HIGHLIGHTS

• Over 16 tons of food scraps converted into nutrient-rich compost
• Engaged 14 undergraduate students as operational assistants
• 15 presentations/tours
• 3 related student course reports 

WHAT’S NEXT

• Plans to grow project by setting up additional campus food scraps collection locations
• Project logo!
• Experimental testing of different compost products (e.g. blends, teas) and applications across campus
• Cost-Benefit, Life Cycle Analysis and additional research efforts

Happy Holidays and New Year!

Stay tuned for updates in 2019.

We start off this week’s BioDIGESTer by welcoming the Scully food cooperative (Scully Co-op) to our list of partnering venues which already includes Frist Campus Center and campus cafes. Although the co-op is only expected to generate a small amount of kitchen scraps, the partnership represents a pilot effort to capture food scraps from residential settings on campus.

See below for last week’s operational statistics, and expect to see Scully Co-op’s contribution to the weekly totals in the coming weeks!

Weekly Data: 12/3 – 12/7

	Food	Wood shavings (BA/CS)	% BA/CS	Compost Off-loaded
Week Totals (lbs.)	3,338	1,032	31%	3,000
CUMULATIVE (lbs)	29,993	8,852	30%	20,500

In this week’s bioDIGESTer, we welcome you into December with an article featuring a Guest Commentary from FOR Solutions and our contribution Case Study on the biodigester. Read more on pages 60 and 61 of Waste Advantage Magazine’s December edition:

https://wasteadvantagemag.com/waste-advantage-magazine-2018-issues/

Weekly Data: 11/26 – 11/30

Lastly we  highlight operational data from the last week of November. We processed slightly less than usual due to limited dining hours over Thanksgiving break weekend. We also off-loaded half the amount of compost to compensate for the lower volume of food scraps over the last two weeks.

	Food	Wood shavings (BA/CS)	% BA/CS	Compost Off-loaded
Week Totals (lbs.)	3,305	1,000	30%	1,500
CUMULATIVE (lbs)	26,655	7,820	29%	17,500