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RESEARCH ARTICLE
Waste generation and carbon emissions of a
hospital kitchen in the US: Potential for waste
diversion and carbon reductions
Cassandra L. ThielID
1,2
*, SiWoon ParkID
1
, Aviva A. Musicus
3
, Jenna Agins
4
,
Jocelyn Gan
4
, Jeffrey Held
4
, Amy Horrocks
4
, Marie A. Bragg
1,5
1Department of Population Health, NYU Grossman School of Medicine, New York City, New York, United
States of America, 2Department of Civil and Urban Engineering, NYU Tandon School of Engineering, New
York City, New York, United States of America, 3Department of Social and Behavioral Sciences, Harvard T.
H. Chan School of Public Health, Boston, Massachusetts, United States of America, 4NYU Langone Health,
New York City, New York, United States of America, 5Department of Nutrition, NYU School of Global Public
Health, New York City, New York, United States of America
*cassandra.thiel@nyulangone.org
Abstract
This study measured the total quantity and composition of waste generated in a large, New
York City (NYC) hospital kitchen over a one-day period to assess the impact of potential
waste diversion strategies in potential weight of waste diverted from landfill and reduction in
greenhouse gas (GHG) emissions. During the one-day audit, the hospital kitchen generated
1515.15 kg (1.7 US tons) of solid waste daily or 0.23 kg of total waste per meal served.
Extrapolating to all meals served in 2019, the hospital kitchen generates over 442,067 kg
(487 US tons) of waste and emits approximately 294,466 kg of CO
2
e annually from waste
disposal. Most of this waste (85%, 376,247 kg or 415 US tons annually) is currently sent to
landfill. With feasible changes, including increased recycling and moderate composting, this
hospital could reduce landfilled waste by 205,245 kg (226 US tons, or 55% reduction) and
reduce GHG emissions by 189,025 kg CO
2
e (64% reduction). Given NYC’s ambitious
waste and GHG emission reduction targets outlined in its OneNYC strategic plan, studies
analyzing composition, emissions, and waste diversion potential of large institutions can be
valuable in achieving city sustainability goals.
Introduction
In 2017, the United States produced over 41 million US tons of total food waste, of which 75%
were landfilled, 19% were combusted, and only 6% were composted [1]. This high proportion
of landfilled food waste produces negative environmental impacts that fuel climate change.
Decomposing food in landfills generates methane, a potent greenhouse gas (GHG) that has a
global warming potential (GWP) 104 times greater than that of carbon dioxide [2]. U.S. land-
fills contribute 95.6 billion kg of GHGs annually as of 2014 [3,4]. Diverting food waste from
landfills is a promising strategy to combat climate change.
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OPEN ACCESS
Citation: Thiel CL, Park S, Musicus AA, Agins J,
Gan J, Held J, et al. (2021) Waste generation and
carbon emissions of a hospital kitchen in the US:
Potential for waste diversion and carbon
reductions. PLoS ONE 16(3): e0247616. https://
doi.org/10.1371/journal.pone.0247616
Editor: Balasubramani Ravindran, Kyonggi
University, REPUBLIC OF KOREA
Received: October 1, 2020
Accepted: February 9, 2021
Published: March 17, 2021
Peer Review History: PLOS recognizes the
benefits of transparency in the peer review
process; therefore, we enable the publication of
all of the content of peer review and author
responses alongside final, published articles. The
editorial history of this article is available here:
https://doi.org/10.1371/journal.pone.0247616
Copyright: ©2021 Thiel et al. This is an open
access article distributed under the terms of the
Creative Commons Attribution License, which
permits unrestricted use, distribution, and
reproduction in any medium, provided the original
author and source are credited.
Data Availability Statement: The data underlying
the results presented in the study are available in
the supplemental file.
Institutional change is crucial for waste diversion, and it can be spurred by citywide poli-
cies and guidance. For example, New York City (NYC) has recognized the threat of climate
change to its communities and has set aggressive goals to reduce its environmental impact.
Launched in April 2015, the city’s OneNYC 2050 strategic plan established climate goals
including zero waste to landfill by 2030 and achieving carbon neutrality by 2050 [5]. The
city’s strategic plan recognizes the important role that institutions can play in reducing the
city’s environmental impact. In February 2016, NYC launched the Mayor’s Zero Waste Chal-
lenge (ZWC), which invited NYC businesses to divert at least 50% of their waste from landfill
and incineration [6]. When ZWC ended in June 2016, the majority of businesses had reduced
landfill waste production by at least 50%. Among the 39 participating locations, 12 locations
diverted more than 75% of their waste and two diverted more than 90% of waste. ZWC was
successful because it targeted businesses with high volumes of food waste and provided a
platform for leadership recognition [6]. Since 2016, New York City has also passed multiple
laws requiring large generators of food waste (e.g., arenas, chain restaurants, grocery stores)
to put their wasted food to good use, such as donating excess edible food and composting
food scraps [7,8].
Despite NYC’s recognition of the importance of institutional change to protect the environ-
ment, the organic waste management of city hospitals have not been included in these regula-
tions. This is a potential missed opportunity, as NYC hospitals have been estimated to generate
5% of commercial food wastes in the city [9]. Most research on hospital food waste has focused
exclusively on wasted food from patient trays, finding that a median of 30% of food on trays is
thrown away uneaten [10–13]. National data suggest that hospitals produce 30 pounds of food
waste per patient bed per day [14]. Few studies, however, have examined the volume, composi-
tion, and carbon footprint of broader food waste production at hospitals, which are crucial
metrics to optimize and reduce food waste at the institutional level and could produce eco-
nomic and environmental benefits [15]. To address the gap in the literature and inform poten-
tial institutional and regulatory actions, this study aims to analyze waste generation over one
day in the kitchen of an academic medical center, including characterizing the waste for diver-
sion potential and quantifying GHG emissions associated with its disposal. The auditing meth-
odology utilized in this paper can serve as a model for other hospitals seeking to reduce their
carbon footprint by diverting food waste from landfill.
Methods
Case location
We measured all waste generated over the course of a single day by New York University Lan-
gone Health’s (NYU Langone) Main Campus on the east side of Manhattan. The Main Cam-
pus is a large academic medical center comprised of 10 interconnected acute care clinical,
research and non-clinical buildings. The Main Campus has a total of 750 total beds, roughly
9,575 onsite Full Time Employees, and 212,574 patient-days annually. The NYU Langone
Department of Food & Nutrition Services provides over 1,900 inpatient meals per day for sev-
eral areas of the Main Campus—Tisch Hospital, the Kimmel Pavilion, and the Schwartz Health
Care Center—and approximately 3,400 retail meals daily at the Tisch Cafe
´, Kimmel Cafe
´&
Coffee Bar, Science Cafe
´& Coffee Bar, Cafe
´41, ACC Cafe
´, and Orthopedic Center Cafe
´. This
institutional scratch kitchen cooks fresh meals daily and develops menus based on seasonality
and availability of fresh produce. Annually, the kitchen prepares over 1.9 million patient and
retail meals.
The kitchen is divided into six workspaces or zones: 1) catering, which serves executive
meetings and on-site conferences; 2) production, which includes main food preparation areas,
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Funding: Funding support was provided by an NIH
Early Independence Award (5DP5OD021373-05)
for MB (https://commonfund.nih.gov/
earlyindependence). AAM is supported by NIH
grant number 2T32CA057711-27. The content of
this article is solely the responsibility of the authors
and does not necessarily represent the official
views of the NIH. The funders had no role in study
design, data collection and analysis, decision to
publish, or preparation of the manuscript.
Competing interests: The authors have declared
that no competing interests exist.
walk-in coolers and freezers; 3) patient services, which prepares trays for inpatient meals; 4)
the pot room, where large dishes are washed; 5) the dish room, for all other dish and tray wash-
ing; and 6) the decanting room, where boxed food deliveries are received, unpacked, and dis-
tributed. Prior to the audit, the kitchen diverted cardboard and metal food packaging to a
recycling waste stream, and all other wastes were sent to landfill. Ethics approval was not
needed, as this was not human-subjects research.
Data collection, waste auditing protocol
To measure and characterize all waste produced by the kitchen, we conducted a waste audit
over the course of a single, typical (non-holiday) weekday in December 2019. In preparation
for the audit, the research team met with food & nutrition services management, kitchen, and
dietetic staff. The initial meeting included a tour of the kitchen and identification of high-level
goals of the project, namely providing baseline data characterizing current waste outputs to
evaluate the feasibility of a composting program. Excluded from the waste audit were the
wastes generated from retail meals (that is, the waste generated by customers in the cafeterias)
as these wastes are sent directly from the cafeteria to the hospital’s waste disposal area. Recycla-
ble materials disposed to landfill were recorded.
A second meeting set the details of the audit, including required physical resources (labeled
trash bags, personal protective equipment for the auditors, and sorting tools such as scales,
buckets, and recording devices) and staff protocols (notifications and potential training
required prior to the waste sorting). Prior to the audit, we created masking tape labels for all 6
kitchen zones and affixed them on over 200 empty trash bags to ensure we noted origins of
waste within the kitchen. Pathways and designated weighing sites were identified to ensure no
waste was missed during the audit. All waste management and food service staff were informed
of the date of the audit.
On the day of the audit, we utilized two different methods of data collection: (1) “all-
day audit”: generic weighing of every bag of waste leaving the kitchen during operating
hours (5:30am–10:00pm); and (2) “detailed audits”: three, one-hour periods where the con-
tents of every bag of waste was sorted and weighed. For both methods of data collection,
full bags of waste were weighed and characterized by the kitchen zones from which the
bags originated. The time each bag reached the loading dock was also noted. We used two
types of scales to weigh bags of waste: a Polysun portable hanging scale for lighter bags
(bags that could easily be lifted out of trash cans), with an accuracy of 10 kg x 5 g or 10–50
kg x 10 g, and a Mettler Toledo IND560 floor scale in the loading docks for heavier bags or
bins.
The detailed audits were performed during three specific time periods assumed to be times
with higher waste-generation rates, based on meal service times: 9:30am to 10:30am, 12:00pm
to 1:00pm, and 3:30pm to 4:30pm. All waste generated during these time periods was first
weighed as full bags. We then opened and sorted each bag of waste into various categories and
weighed each waste category separately. Waste was separated into the following categories:
compostable food/organic wastes; recyclable glass, metal, beverage cartons and plastic; recycla-
ble papers & paperboards; non-recyclable plastics; gloves used by food service workers; and
other general wastes (including disposable flatware). We also made note of unused items, such
as unopened drink cartons returned on patient trays. Here, we used an Edlund ERS-60 accu-
rate to 30 kg x 5 g for weighing. The auditors rotated throughout the day, using the same data
collection sheets. There were ten auditors in total, two of which served as supervisors to ensure
consistency in data collection.
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Data analysis
Descriptive statistics were used to characterize the quantity and timing of waste generation
from the all-day and detailed audits. We further estimated the composition of waste generated
per day by calculating the proportion of waste in each composition category described previ-
ously (e.g., compostable food/organic wastes) from each kitchen zone during the detailed
audits and multiplying this by the total daily waste from each kitchen zone. Annual waste gen-
eration was estimated by dividing daily results by the number of meals served on the audit day
and multiplying by the total number of meals served in 2019 (696,485 inpatient meals and
1,248,410 estimated retail meals).
Based on waste composition estimates, we calculate three waste diversion scenarios: 1) the
number of pounds of annual waste produced from existing paper and metal recycling with all
other waste sent to landfill (current hospital practice or Base Case), 2) the number of pounds
of annual waste in the ideal scenario in which everything that could be recycled or composted
were diverted from landfill (ideal), and 3) the number of pounds of annual waste in the most-
likely scenario of increased recycling and compost diversion based on the kitchen’s setup and
the likelihood of regular sorting occurring (likely future). In the likely future scenario, all dish
room waste would go to landfill because the kitchen staff deemed sorting of dish room waste
to be almost impossible due to staffing resources, safety, and space considerations, but all
other recycling and compostable materials would be diverted from landfill. Of note, these sce-
narios do not include post-consumer waste from the cafeterias or retail meals.
Finally, we estimated annual GHG emissions for disposal and treatment of waste in each of
the diversion scenarios described above. The conversion factor of kg carbon dioxide equiva-
lents (CO
2
e) were taken from the US EPA’s Documentation for Greenhouse Gas Emission
and Energy Factors Used in the Waste Reduction Model (WARM), Exhibit 5–1 (composting
food waste) and Exhibit 7–16 (landfilling food waste) [16]. In this model, composted material
produces a net negative GHG emission factor because compost acts as a carbon sink. We did
not estimate GHGs from upstream activities (such as farming or cooking), and we did not
issue any emissions or CO
2
e credits to the hospital for the material it recycled, as it is standard
practice within life cycle assessment methods to assign CO
2
e reductions credit only to account
for utilized recycled materials.
Results
On the day of our audit, the total waste (trash, recyclables, and compostable waste) recorded
leaving the kitchen weighed 1515.2 kg (1.7 US tons) in 171 bags. The average waste generation
rate was 94.7 kg/hr (209 lbs/hr) and 10.7 bags/hr over the 16-hour audit. On this day, the hos-
pital served 2,010 inpatient meals and 4,656 retail meals generating 0.23 kg (0.51 lbs) of total
waste per meal. Assuming this represents an average daily waste generation, this case study
kitchen will produce an average total waste of 442,067 kg (487 US tons or 974,590 lbs) per year
and use approximately 49,892 plastic garbage bags.
Out of all kitchen zones, a majority of waste originated in the dish room (535.8 kg or 35%
of total waste) where patient trays are cleaned and the pot room (309.8 kg or 20%) where cook-
ware are cleaned (Fig 1). The next largest zones of waste generation were the production area
for general food preparation (208.1 kg or 14%) and patient services, where inpatient trays are
prepared (191.9 kg or 13%). The decanting room, where food deliveries are unpacked, gener-
ated 188.2 kg or 12% of total waste, most of which was cardboard boxes used for packaging. A
small portion of this, by weight, was plastic wrap used to secure the boxes, but this was not
weighed separately. The catering area generated only 54.6 kg or 4% of total waste. The remain-
ing 26.8 kg (2%) of general waste came from four unlabeled bags thought to originate in the
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dish room or decanting room (unlabeled garbage bags were accidentally used around 7pm,
but the issue was quickly remedied).
Detailed audits were conducted on 34 bags (20% of daily total), representing 272.9 kg of
waste (18%). The only kitchen areas without detailed audits were the decanting room and the
pot room. In observations prior to and on the day of the audit, the decanting room generated
mainly cardboard waste and some plastic shrink wrap (the total weight considered to be recy-
cling) and the pot room generated only compostable waste (food liquid and solids). Extrapolat-
ing the detailed audits to the daily total by kitchen area reveals the potential amount of
recyclable and compostable material originating in each kitchen area (Fig 1). Recyclable paper
products made up 215.8 kg or 14% of the total waste. Of this, 93% is already being captured for
recycling. Recyclable metals, plastics, or glass made up 124.8 kg (8%) of total waste, of which
20% is already being captured for recycling. Organic materials that could be sent to a compost-
ing facility made up 861.6 kg (57%) of the total waste with compostable service ware (lids,
spoons, and forks) making up 5.2 kg of total waste (<1% of total and about 1% of compostable
waste). Thin film plastics made up 168.1 kg (11%) and gloves represented 20.5 kg (1%).
Unused items, or unused food found in unopened original packaging including drink cartons
and individually wrapped food items, made up 93.5 kg or 6% of total waste. Most unused
items came from the dish room, where returned patient trays are washed, although some origi-
nated in production, where expired and near-expired items from the freezers and refrigerators
are disposed per regulations.
Waste generation and type of waste generated varied throughout the day, with more recy-
clable materials emerging early in the day, shown in Fig 2. Peaks in waste generation occurred
in late morning before lunch time and mid-afternoon before dinner. An additional peak
occurred at the end of the day, when the freezers and refrigerators were cleaned, resulting in
Fig 1. Waste generation for case hospital kitchen on the day of the audit, with estimated compositions by kitchen zone.
Estimated composition determined by extrapolation from detailed audits of 20% of waste bag sample. “Unused items” refers to
unused food found in original unopened packaging. “Other wastes” refers to garbage that does not fit into other categories (e.g.,
disposable flatware).
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the disposal of expired supplies. Amount of compostable material ranged between 16% of total
waste (morning) to 89% of total waste (around 7PM), though these factors may vary depend-
ing on the day (e.g., a weekend instead of a weekday).
Extrapolating the detailed audit to all day audit results show some large potential for waste
diversion, though there are operational and regulatory barriers to implementing diversion
strategies. In the current or Base Case scenario, the only waste diverted from landfill by the
kitchen consisted of 200.7 kg of recyclable cardboard and 24.9 kg of metal, plastic, or glass
(approximately 15% of total waste daily), shown in Fig 3. In an ideal scenario, all possible
compostable food and service ware items and all recyclable items would be captured and
diverted. If the hospital’s daily measured generation of 861.6 kg of compost, 215.8 kg of paper,
and 124.8 kg of other recycling were to be properly diverted, the total waste to landfill could be
reduced by 76% by weight (Fig 3), resulting in only 313.0 kg of total waste to landfill daily or
91,330 kg of waste to landfill annually. For this kitchen, a more realistic scenario limits com-
posting to catering, production, patient services, and the pot room, for an estimated 55%
reduction in waste to landfill (including 588.5 kg daily to compost), resulting in 586.1 kg of
total waste to landfill daily or 171,002 kg of waste to landfill annually. However, even this sce-
nario many be overestimated due to potential barriers associated with logistics, space con-
straints, and resources required.
Based on these waste diversion scenarios, we estimated that the hospital kitchen generates
294,466 kg CO
2
e per year from its current waste disposal practices (Base Case), in which all
cardboard is recycled, some metals and plastics are recycled, and all other waste is sent to land-
fill (Fig 4). This is equivalent to the annual emissions from 64 standard US passenger cars and
would require 386 acres of US forest growing for one year to absorb the released greenhouse
gases [17]. Implementing the “ideal scenario” of diverting all possible materials would result in
cumulative carbon emissions of 29,913 kg CO
2
e annually (a 90% reduction in GHGs), equiva-
lent to emissions from just less than 7 passenger vehicles on the road each year. This hospital
Fig 2. Estimated composition of waste generation of case study hospital on day of audit over time.
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kitchen’s likely waste diversion scenario would result in emissions of 105,441 kg CO
2
e per year
(a 64% reduction from baseline), equivalent to 23 passenger vehicles on the road each year.
Discussion
In this study, we found that a single hospital in NYC annually generates 442,067 kg of waste
(487 US tons) and emits approximately 294,466 kg of CO
2
e from waste disposal. The majority
of this waste (85%, 376,247 kg or 415 US tons annually) is currently sent to landfill. If the hos-
pital were to increase recycling rates and implement composting in a feasible manner, it could
reduce landfilled waste by 205,245 kg (226 US tons, or 55% reduction) and GHG emissions by
189,025 kg CO
2
e (64% reduction). Although an ideal waste diversion scenario would divert
76% of waste from landfill and reduce GHG emissions by 90%, it would be particularly chal-
lenging to achieve due to available commercial composting facilities, vendor restrictions, staff-
ing resources, space constraints, logistics, and expenses. Despite a dearth of data on waste
diversion in other hospitals, one case study of a 250-bed hospital in San Francisco estimated
that an institutional waste diversion program could result in an annual reduction of 51 US
tons of landfilled waste [18]. That estimate is lower than the one found in this study, which is
likely due to differences in the size of the hospitals’ patient populations and foodservice opera-
tions, and variations in waste diversion strategy design.
Fig 3. Estimated daily waste generation and diversion scenarios for case hospital kitchen, based on one-day audit. Current (Base
Case) = kitchen diverts cardboard and some metal recycling only; Ideal = recycling and composting of all possible materials; Likely
Future = recycling and composting of likely materials based on feedback from kitchen staff.
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Despite structural differences between hospitals, diverting organic and recyclable hospital
waste from landfills could be highly impactful if implemented across NYC, as the city is home
to 41 hospitals and 15,841 beds [19]. An extrapolation of our findings across all NYC hospitals
based on the number of beds suggests that composting in NYC hospitals could result in a 3.9
million-kg (4,200 US tons) reduction in landfilled waste and 3.5 million-kg (3,900 tons) reduc-
tion in GHGs, the equivalent GHG savings as removing 1,674 passenger vehicles from the
road each year [17]. Based on these data and existing literature, several strategies and policy
changes may help (1) prevent food waste and (2) divert remaining wastes in institutional food
services.
First, hospitals can focus on operational procedures to decrease food waste and emissions,
as our study found that 35% of food waste came from the area that cleans inpatient food trays,
and 7% of food was discarded unopened. Studies suggested that creating greater patient auton-
omy in food decisions can reduce tray waste [20]. Some hospitals allow patients to select their
meal from a menu, while still incorporating their recommended dietary restrictions, and allow
patients to select which condiments, beverages, and utensils they prefer. This is done at NYU
Langone Health. However, state and federal regulations often lead hospital food services and
other institutions to deliver items that patients will ultimately waste, such as milk cartons [21,
22]. Other studies of institutional food waste have identified additional strategies to mitigate
Fig 4. Estimated annual carbon emissions from waste diversion scenarios in the case hospital kitchen. Current (Base Case) =
kitchen diverts cardboard and some metal recycling only; Ideal = recycling and composting of all possible materials; Likely
Future = recycling and composting of likely materials based on feedback from kitchen staff. Greenhouse Gases (GHGs) from
composting are assumed to be carbon negative. No carbon credit is issued for recycling, so it is not included in this figure.
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tray or plate waste, including: smaller serving sizes and educational campaigns [20,23–25],
implementing support systems to overcome clinical barriers [26], and addressing service issues
such as complex ordering systems or environmental factors such as inappropriate meal times
or unpleasant ward surroundings [12,27]. Some issues, such as serving sizes, are controlled by
dietary regulation and USDA guidelines making it more difficult for hospitals to adjust prac-
tices that lead to waste. Strategies that are not restricted by regulation may be easier to imple-
ment based on the size and structure of the hospital and its food service department. Regular
and ongoing tracking of food waste is recommended as part of a reduction strategy; however,
it is not often performed in hospital food services [28,29]. Tracking food waste can help estab-
lish a baseline, identify opportunities for reduction, and report progress to staff and leadership.
Second, our study found that the production area of the kitchen generated 12% of total
waste, suggesting that upstream strategies focusing on procurement, inventory management
practices, and production approaches may be equally helpful in minimizing potential food
waste and increasing opportunities for diversion. Careful planning to avoid unnecessary food
waste is core to any food service, as this will also save money. Though not measured in this
study, procurement practices can reduce upstream emissions. These include prioritizing
locally grown, organic, and in-season produce (which notably may not always reduce GHGs);
reducing animal proteins in meals; offering more vegetarian and vegan options; sourcing pro-
duce and meats more sustainably; and purchasing reusable, compostable, or recyclable prod-
ucts [29–32]. Operational improvements such as energy and water efficiency upgrades can
also reduce the larger footprint of food services [33,34].
Third, if food is still usable, preference should be given to ensuring the food ends up being
eaten. However, one concern often cited is the legal ramifications of donating unused food.
Policymakers and hospitals could become familiarized with the food waste policies in their
states. Some US states, for example, protect donors from legal consequences if someone gets
sick as a result of consuming donated food. New York State recently passed a Food Donation
and Food Scraps Recycling Law, which will require large generators of food scraps to donate
excess edible food and recycle all remaining food scraps starting January 1, 2022; however,
New York City is exempt as it has its own policy and hospitals are also exempt [35]. Unfortu-
nately, logistical concerns for implementing a donation program can often be prohibitive for
many hospitals, though these issues may present an opportunity for aspiring businesses or
non-profits.
Finally, food and recyclable wastes should be diverted from landfills, either through com-
posting, recycling, or anaerobic digestion, which uses microorganisms to break down organic
material into biogas, which can be used as a renewable energy source. Substantial barriers exist
to implementing these strategies, however. Many hospitals need to establish contracts with pri-
vate or commercial composters/anaerobic digestion operators, and for many, recycling is a
much more commonly implemented waste diversion initiative [36]. Cities might consider sup-
porting local composting infrastructure, and enacting legislation that encourages large institu-
tions to utilize these waste streams. For example, prior to COVID-19, the NYC Department of
Sanitation (DSNY) offered composting in residential areas and for non-profit organizations.
DSNY also partners with a non-profit called GrowNYC that facilitates food scrap drop-off
sites in local farmers markets.
These recommendations may be applied to other institutional kitchens, such as cafeterias at
large universities or military bases. However, more research is needed to understand how food
waste can be reduced in other sectors responsible for feeding thousands of people. Given the
complex factors that may be involved in reducing food waste (e.g., changing the status quo,
composting markets, and local regulations), future studies should also qualitatively examine
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perceived barriers to reducing and diverting food waste in hospitals and other large food ser-
vice providers [32,34].
Limitations
This study analyzed only one hospital kitchen on a single day. Variability obviously exists by
day of the week, season, and year, and by the way in which a hospital’s food service operates.
Additionally, this study did not capture staff and visitor waste from retail meals, as the cafete-
ria’s front-facing waste stream does not come through the kitchen. As a result, this study
underestimates the hospital’s total food service wastes and potential diversion opportunities.
In addition, this study used a sampling frame to estimate the composition of daily kitchen
wastes. This study also utilized GHG factors from the US EPA’s WARM model, which con-
tains its own assumptions about landfilling, recycling, and composting. Other GHG models
may estimate emissions differently. Future studies should audit waste in detail over a longer
time period (e.g., multiple days throughout the year), and further investigate opportunities to
reduce staff and visitor cafeteria waste. Future studies should also investigate other opportuni-
ties for organic waste diversion, including anaerobic digestion, and calculate and compare
costs of various waste diversion strategies, including composting, anaerobic digestion, and
recycling.
Conclusion
Hospital kitchens and other institutional food services generate a substantial amount of solid
waste and greenhouse gas emissions. However, there are ample opportunities to reduce and
divert this waste from methane-producing landfills. Using waste audit methods at a case loca-
tion, we found that the hospital kitchen in this study annually sends 85% of its waste—415 US
tons—to landfill, but that it could feasibly reduce its waste to landfill by 55% and subsequently
reduce its GHG emissions by 64%. This study provides a valuable framework from which hos-
pitals and policymakers in NYC and elsewhere can begin to measure and subsequently reduce
institutional food waste. It is also particularly timely, as NYC’s OneNYC strategic plan has tar-
geted sustainability goals including Zero Waste by 2030 and carbon neutrality by 2050.
Supporting information
S1 Data.
(XLSX)
Acknowledgments
The researchers would like to thank Purnima Prasad, Omni Cassidy, Tenay Greene, and Josh
Arshonsky for their help conducting the waste audits. We would also like to thank NYU Lan-
gone Health Department of Food & Nutrition Services and NYU Langone Health Department
of Building Services workers for their assistance in making the audit a success.
Author Contributions
Conceptualization: Cassandra L. Thiel, Jenna Agins, Jocelyn Gan, Jeffrey Held.
Data curation: Cassandra L. Thiel, SiWoon Park, Jenna Agins, Jocelyn Gan, Marie A. Bragg.
Formal analysis: Cassandra L. Thiel, SiWoon Park, Jocelyn Gan.
Investigation: Cassandra L. Thiel, SiWoon Park, Jocelyn Gan, Jeffrey Held, Marie A. Bragg.
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Waste generation and carbon emissions of a hospital kitchen in the US
PLOS ONE | https://doi.org/10.1371/journal.pone.0247616 March 17, 2021 10 / 12
Methodology: Cassandra L. Thiel, SiWoon Park, Jenna Agins, Jocelyn Gan, Jeffrey Held,
Marie A. Bragg.
Project administration: Cassandra L. Thiel, Jenna Agins, Jocelyn Gan, Jeffrey Held, Amy
Horrocks.
Resources: Cassandra L. Thiel, Jocelyn Gan, Jeffrey Held, Amy Horrocks, Marie A. Bragg.
Software: Cassandra L. Thiel.
Supervision: Cassandra L. Thiel, Amy Horrocks, Marie A. Bragg.
Validation: Cassandra L. Thiel, Aviva A. Musicus, Jocelyn Gan, Jeffrey Held.
Visualization: Cassandra L. Thiel, SiWoon Park, Jocelyn Gan.
Writing – original draft: Cassandra L. Thiel, SiWoon Park, Aviva A. Musicus, Amy Horrocks,
Marie A. Bragg.
Writing – review & editing: Cassandra L. Thiel, Aviva A. Musicus, Jenna Agins, Jocelyn Gan,
Jeffrey Held, Amy Horrocks, Marie A. Bragg.
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