Systems for the Management
and Disposal of Food Waste

Life Cycle Assessment
JULY, 2011

SUMMARYBACKGROUND
According to the US EPA, food waste isthe single largest component ofmunicipal solid waste sent to landfills1
and many communities worldwide arefocusing efforts to divert this organicwaste.2,3 Much of the effort is intended toreduce greenhouse gas emissions,particularly at landfills. Landfills areconsidered the third largest source ofmethane,4 a gas 21 times more potent
than carbon dioxide,5 so various
alternatives are being explored. Acommon yet overlooked means ofdiversion includes the use of food waste
disposers to send food scraps towastewater treatment plants forprocessing. Approximately 50% of all US
homes have an installed disposer6.
For

decades,

wastewater

treatment

plants protected public health byproviding sanitary management of
human waste but more recently, theseplants have come to be recognized as“resource centers” – producers of cleanwater, fertilizer and energy. Because foodscraps average 70% water, divertingthem to wastewater treatment plants is aproven disposal option. InSinkErator,® theWisconsin-based manufacturer of foodwaste disposers, sought to better
understand the environmental impacts ofthese appliances using various types ofwastewater treatment in comparison toother methods of management such as
landfilling and composting. InSinkErator
is a division of Emerson Electric Co.

GOAL
The Goal of the Life Cycle Assessment(LCA) study was to understand theenvironmental impact of food waste
disposal pathways in order to help policy
makers and others assess the role of foodwaste disposers in their waste
management programs.

THE REPORTCamp Dresser & McKee (CDM)
conducted the initial analysis used by PE
International, Inc. to produce a life cycle
assessment and report. A thorough andindependent review of the LCA wasundertaken by a panel of third-party
experts.
The study was conducted in accordancewith the ISO 14040 series of standards torepresent a gate-to-grave comparative
assessment of multiple food waste
management systems.

Gate-to-Grave System Boundary
Food Waste
Disposal

Transport Conveyance

Treatment ofFood Waste

Trash Bagand Can

Truck Transport

Landfill
CompostFacility

Food Production,Distribution,
Consumption

Waste toEnergy Facility
Sink via
DisposerConveyancein Sewer

Wastewater
Treatment Plant

1“Basic Information About Food Waste.” US EPA. April 29, 2011. http://www.epa.gov/osw/conserve/materials/organics/food/fd-basic.htm

2European Commission. 1999. “Landfill of Waste.” [Internet, WWW]. Available: European Commission;
http://ec.europa.eu/environment/waste/landfilliatindex.htm. [Accessed; 2 December 2010.]

3

California Green Solutions. 2006. [Internet, WWW]. Available: Green Solutions;
http://www.californiagreensolutions.com/cgi-bin/gt/tpl.h,content=297. [Accessed; 2 December 2010.]

4US EPA. 2007. “Inventory of US Greenhouse Gas Emissions and Sinks: 1990 – 2005.”

5Intergovernmental Panel on Climate Change. 1996. “Climate Change 1995: The Science of Climate Change.”

6United States Census Bureau. 2010. “American Housing Survey.” [Internet, WWW]. Available: U.S. Census Bureau;
http://www.census.gov/hhes/www/housing/ahs/ahs09/1-4.xls [Accessed; 10 November 2010.]

Systems for the Management andDisposal of Food Waste

Life Cycle Assessment

SUMMARY

SCOPE

from reflected sunlight that would
have otherwise passed out of theearth’s atmosphere.

Twelve end-of-life disposal options weremodeled to represent the majority offood waste pathways in the United States
including:• Warehouse operations and shippingof product• 8 wastewater treatment
plant systems• End-of-life disposition of the disposer ina landfill• 1 incineration system

For the landfill, waste-to-energy andcomposting systems, the gate-to grave
impacts were considered for the waste
receptacle and trash bag.

• Consumption of water and power tooperate the disposer• 2 landfill systems• 1 composting system
The assessment considered the impacts
frommanufacturing,packaging,distribution, and use of a food waste
disposer over its 10-year life, and disposalat end-of-life. These included:

Using a functional unit of 100 kg* of foodwaste to represent an average amount ofhousehold waste disposed of in a year, thescenarios were evaluated for potential
environmental impacts according to ISO
protocol including:• Manufacturing, including raw materials,
energy, emissions and wastes• Global warming: change in theearth’s climate caused by thebuild-up of chemicals that trap heat

• Raw materials used for productpackaging*0.21 LBS FOODWASTEPERSONDAYx

2.6 PERSONSHOUSEHOLD

x365
DAYS
YEAR

xkg
2.2046
LB=• Eutrophication: the process ofexcessive vegetative growth occurring
in aquatic environments as a result of
the high concentration of nutrients.
• Acidification : increase in the acidity(hydrogen ion concentration) ofwater and soil systems.
• Smog formation: the creation of air
pollution resulting from interactionof sunlight with certain chemicals inthe atmosphere.
• Primary energy demand: a measureof the total amount of primary energy
associated with the product andprocesses within the life cycle
assessment boundaries.

97 kg
YEAR

MAJOR FINDINGS
Using a disposer in conjunction with any of the eight wastewater treatment
systems results in lower global warming potential than both landfilling options.
Global Warming Potential - (kg CO2e)
90.0

SYSTEM DEFINITIONSPage 4

80.0
70.0
60.0
50.0
40.0
30.0
20.0
10.0
0.0
-10.0

Landfill with
Generation

Landfillwith Flare

LANDFILL

Extended
Aeration

Extended
Aeration/
Landfill

Extended
Lime/
Stab

Conventional
Treatment/
Incineration

Conventional
Lime
Stab

WASTEWATER TREATMENT

Conventional
Conventional
Conventional
Treatment/
Treatment/
Treatment/
Anaerobic Digestion/ Anaerobic Digestion/ Anaerobic Digestion/
Flare
BoilerCogeneration

Systems for the Management andDisposal of Food Waste

Life Cycle Assessment

SUMMARY

8REDUCED
CARBONFOOTPRINT

EQUIVALENTTO

S
LEMI30,000
TREATMENT
HOUSEHOLDS WASTEWATEROPTIONSFOR FOODUSINGWASTE DISPOSAL

NIO
LL
MI
4.6

For a community of 30,000 households,
using any of the eight wastewater
treatment options to dispose of foodwaste instead of landfilling on average
would reduce the carbon footprint by 1.9
million kg, the equivalent of not driving 4.6
million miles.

Global Warming Potential - (kg CO2e)
Sophisticated emissionscontrolled composting andincineration also result in
lower global warming
potential than landfilling.

90.0
80.0
70.0
60.0
50.0
40.0
30.0
20.0
10.0
0.0
-10.0

Landfill/
Congeneration

Landfill
Flare

Waste-toEnergy

Composting(EmissionsControlled)

Primary Energy Demand - Megajoule (MJ)
Using a disposer in combination
with advanced wastewater
treatment results in the lowest
primary energy demand.

200
180
160
140
120
100
8060
40200

Landfill/
Flare

Landfill/
Cogeneration

Waste-to-Energy

Composting(EmissionsControlled)Conventional Wastewater
Treatment/Anaerobic
Digestion/
Cogeneration

Systems for the Management andDisposal of Food Waste

Life Cycle Assessment

SUMMARY
DEFINITIONS
Composting (Emissions-Controlled) Centralized membrane covered aerated
static pile composting technology

Conventional Treatment/Incineration Conventional activated sludge processwith incineration of biosolids

Landfill with Generation – Landfill
where biogas is used to generate
electricity

Conventional Treatment/Anaerobic
Digestion/Boiler - Conventional
activated sludge process with anaerobic
digestion, biogas used in boilers, andbiosolids land applied

Conventional/Lime Stab - Conventionalactivated sludge process with lime
stabilization, and land application ofbiosolids

Landfill with Flare – Landfill where
biogas is flared

Conventional Treatment/Anaerobic
Digestion/Cogeneration - Conventional
activated sludge process with anaerobic
digestion, biogas used for cogeneration,and biosolids land applied

Extended Aeration - Extended aeration
sludge process with aerobic digestion,and biosolids land applied
Extended Aeration/Landfill - Extended
aeration sludge process with aerobic
digestion, and biosolids landfilled

Conventional Treatment/Anaerobic
Digestion/Flare - Conventional
activated sludge process with anaerobic
digestion, biogas flared, and biosolids
land applied

Extended/Lime Stab - Extended
aeration sludge process with lime
stabilization, and land application ofbiosolids

For More Information
The report can provide important
informationtohelpcommunity
stakeholders understand and assess
impacts, risks and opportunities associatedwith various organic waste management
practices and the impact of the utilizationof food waste disposers.

For a copy of this document, the Executive
Summary or the complete Life Cycle
AssessmentofSystemsfortheManagement and Disposal of Food Waste
report, please visit the InSinkErator® website atwww.insinkerator.com/lifecycleassessment
Or write to us at the address below.
Life Cycle Assessment Inquiry
InSinkErator
4700 21st Street
Racine, WI 53406

Waste-to Energy - Mass burn municipal
solid waste facility with a reciprocatinggate furnace and an integral heatrecovery boiler
Megajoule (MJ) – One million (106)joules; a joule is a unit of energy

Headquartered in Racine, WI, InSinkErator,
a division of Emerson, is the world’s largest
manufacturer of food waste disposers andinstant hot water dispensers. For more
information about InSinkErator visit
www.insinkerator.com
Emerson, based in St. Louis, MO, is a global
leader in bringing technology andengineering together to provide innovative
solutions for customers in industrial,commercial and consumer markets
through its network power, process
management,
industrial
automation,
climate technologies, and appliance andtools businesses. For more information, visit
www.Emerson.com

The Emerson logo is a trademark and service mark of Emerson Electric Co.

1.800.558.5700
www.insinkerator.com© 2011 InSinkErator, InSinkErator is a division of Emerson Electric Co. All Rights Reserved.
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