UW Anaerobic Digester: Food Waste, Renewable Energy & Public Health (Phase 2)

Executive Summary:

The University District Food Bank (UDFB) serves some of the poorest and most vulnerable individuals in the North Seattle and University District community. The University District has one of the highest rates of poverty in Seattle, which was shown in by 2016 study that approximately 60% of University District residents have an income at or below the federal poverty threshold (Keeley, 2016). These residents often cannot access enough healthy and nutritious food and depend on UDFB to survive. UDFB distributes 45,000 pounds of food (i.e. fruits, vegetables, dairy, bread, canned food, etc.) to over 1,200 families per week, maintains a 2,000 square foot rooftop garden, and co-locates with a café (Street Bean) that employs homeless and low-income youth.


UDFB is struggling with a tragic irony though—there is too much food waste. Grocery store chains often use food banks (including UDFB) as a dumping ground for expired or damaged food, while receiving a tax break for the donation. UDFB receives food that spoils quickly, and in turn, UDFB pays ~$6,000 per year to haul away food waste to a municipal composting facility. The garbage trucks that haul away the food waste pollute the North Seattle neighborhood. The exhaust from these trucks is a public health risk for individuals and families.  This inexcusable situation prevents the food bank from using their financial resources to better serve the community.

Many residents also feel stigmatized when they use the food bank. A 2016 Seattle Times article documented the feelings of one community member, “When I was going to the food bank, it’s not like I was talking about it...it’s something people don’t talk about” (Balk, 2016). This stigma hinders the food bank from integrating into the community and increasing access to UDFB’s resources.

To address these pressing community, environmental, and public health issues, we propose building an anaerobic digester at UDFB. A digester would utilize food waste to create compost and natural gas. The compost would be used on UDFB’s rooftop garden and the gas would provide electricity to power UDFB’s refrigeration system. By reducing food waste and electricity costs, UDFB would save ~$12,000 per year. With these funds, UDFB would expand their services and hire 1-2 youth who are transitioning out of homeless. These youth would operate and maintain the digester to gain job skills. UDFB also wants to create a strong educational partnership with the University of Washington (UW). Dozens of UW students and staff already volunteer at UDFB: serving clients and working on the rooftop garden, but there is no academic partnership with UW. This is an opportunity for a UW-UDFB academic partnership focusing on civil/environmental engineering, soil science, public health, and small business development. Dr. Heidi Gough from the Department of Civil & Environmental Engineering would like to sign a Memorandum of Understanding (MOU) with UDFB to formally incorporate the digester into her graduate and undergraduate curriculum, and Dr. Sally Brown from the School of Forest Resources may also be interested in incorporating the digester into her graduate/undergraduate curriculum.  

Student Involvement:

This project would involve 10-15 UW graduate/undergraduate student volunteers per year. These students would conduct research projects on any aspect of the digester (e.g. gas composition, compost, engineering, business, etc.). A UW faculty member (Dr. Heidi Gough or Dr. Sally Brown) would supervise these students and oversee their research papers/projects.

The local small-business (Impact Bioenergy) that designs and builds anaerobic digesters would build a custom-designed digester at UDFB. Volunteers from the community (residents, UW students, nonprofit organizations) could participate in building the anaerobic digester, and the UW student volunteers could also be trained to lead digester tours for UW students and community members. 

A UW Registered Student Organization (RSO), Global Sustainability Initiative (GSI), has been the main RSO supporting student involvement and interest in this project. The undergraduate members include: Caelan Wisont, Zhaoyi Fang, Yushan Tong, and Kyler Jobe. GSI focuses on promoting sustainability on a global scale, emphasizing household-scale anaerobic digestion projects to create methane gas for stoves. GSI grew out of SafeFlame LLC, which was started by a UW MBA graduate (Kevin Cussen), and received a CSF grant in 2015-2016. GSI also connects interested students to anaerobic digestion projects and gets students excited about working with anaerobic digestion, renewable energy, and public health. GSI would promote interest among other RSOs and recruit undergraduate students from the Sustainability Studio (ENVIR 480) course to conduct research projects on the anaerobic digester.

The digester project team has also reached out to the following RSOs to increase student support/interest: Eco-Reps, Huskies for Food Justice, Students Expressing Environmental Dedication (SEED), and Engineers Without Borders.

The University of Washington (UW) is located within 10 minutes walking distance of the UDFB, but the UDFB receives relatively little attention from the UW community. Very few people at UW are aware of the food bank and its mission, and we believe this anaerobic digestion project would help establish a thriving partnership between UW and the UDFB. With an anaerobic digester, there would be a variety of departments, students and professors that could collaborate with the food bank. Several environmental departments at UW, such as Civil & Environmental Engineering and School of Forest Resources are eager to conduct research projects on the anaerobic digestion process. There is a wide range of topics and ideas that could be explored: the engineering of how to design/construct an efficient and safe digester for community-level operations, the microbiology of how food waste can be turned into compost, and the public health of how an anaerobic digester can address food insecurity. Undergraduate students, graduate students, and professors would be able to support the food bank with ideas and projects on how to improve the anaerobic digestion process. Although this project is not located on the UW campus, we believe that it is reasonable to ask for Campus Sustainability Funding (CSF) to support this project because of the potential to establish a strong academic partnership between UW-UDFB, which would give students and faculty access to digester technology. This collaboration between UW and the UDFB would be the first in the nation (we know of no other university in the U.S. that has partnered with a food bank to study its anaerobic digester).

In summary, building an anaerobic digester would allow UDFB to:

a) Host free community workshops focusing on food waste utilization and renewable energy production.

b) Reduce food waste disposal costs and increase services to residents.  

c) Become a center of community education about food waste, public health, and renewable energy.

d) Establish a strong academic and educational collaboration with UW.

Education & Outreach:

We will publicize our project in three ways:

1) RSOs: GSI and the other RSOs listed above will advertise this project to UW students and publicize this digester project during their tabling events. GSI is the main undergraduate student group that is helping to push this project forward, and their current network with other RSOs will help raise awareness about our project on the UW Seattle campus.

2) Signage: If the digester is built, we will create signage on/around the digester with educational information about anaerobic digestion. For instance, the signage will explain how anaerobic digestion works, how the gas/compost is being used, statistics/scale of the current project, how the project could be scaled up, other digester projects currently happening in Seattle, etc. These signs would be located on the outside of the digester and available for anyone to read.

3) Undergraduate/Graduate Courses: The faculty members collaborating on this project (Dr. Heidi Gough, Department of Civil & Environmental Engineering; Dr. Sally Brown, School of Forest Resources) will encourage their undergraduate and graduate students to conduct research projects on the anaerobic digester. Dr. Gough is primarily interested in the gas production and how changing the inputs (types of food waste) affects the composition of the gas. Dr. Brown is interested in soil science and how the type of food waste affects the chemical makeup of the compost. Additionally, we will do a quarterly presentation for the Sustainability Studio (ENVIR 480) course. This would be a 15-20-minute presentation for the undergraduate students in this course at the beginning of each quarter. ENVIR 480 focuses on sustainability, and a previous group of students from this course conducted a research project on anaerobic digestion.

In addition to publicizing the UDFB project, we will continue to investigate the interest and potential for building an anaerobic digester on the UW campus. We had originally been pursuing CSF funding and gathering student/faculty/staff support build a digester on the UW campus. There has been support for the project, but it is proving to be difficult to find a location for the digester on the UW Seattle. We will continue to investigate interest and feasibility for this UW project, as a way of conducting student outreach.

Environmental Impact:
  • Energy Use
  • Food
  • Waste
Project Longevity:

This project will be maintained by UDFB staff. UDFB will employ 1-2 part-time staff members to maintain the digester (e.g. monitor temperature, pH, etc.). UDFB will have ongoing funding for these positions because they will be spending less money on hauling away food waste and saving money on electricity. 

The academic partnership between UW-UDFB would continue in the long-run because of the MOU that would be signed by Professor Gough and Professor Brown. As the digester project gains more attention at UW, more faculty will hopefully incorporate the digester into their curriculum and more RSOs will include the digester in their outreach activities.

Environmental Problem:

Food waste is an urgent public health issue. In the U.S., approximately 31% of post-harvest food is wasted (i.e. thrown away or spoiled). This is approximately 133 billion pounds of food annually, costing approximately $161 billion (“USDA | OCE | U.S. Food Waste Challenge | FAQ’s,” n.d.). This is shocking and shameful, given national rates of food insecurity and poverty. In addition, food waste often rots in landfills, creating methane gas, which is nearly 4x as damaging to the ozone layer as CO2 emissions. We must address food waste at the local, city, and national level.


This anaerobic digester project would provide a small-scale model of how to utilize food waste to produce renewable energy and compost. The anaerobic digester that we are proposing to install is custom-built by a Seattle-based business called Impact Bioenergy (http://impactbioenergy.com/). The digester is approximately 900 square feet and can process ~850-960 pounds of pre-consumer food waste per day. The digester can store ~1,227 square feet of RNG, which would power UDFB’s refrigeration system. Although this is a relatively small-scale model, it will show how a community organization can utilize food waste to produce RNG, which reduces methane emissions, carbon emissions, and pollution associated with hauling food waste to composting facilities/landfills. Other universities in the U.S. have installed anaerobic digesters, but we do not know of any other universities/colleges in the Pacific Northwest Region that have partnered with a food bank that has an anaerobic digester.


The anaerobic digestion project would reduce pollution in the University District neighborhood by reducing the number of garbage trucks that haul away food waste from the UDFB. By diverting food waste to the anaerobic digester, the UDFB would be supporting fuel conservation and would benefit the University District (and Washington State) by advancing bioenergy, increasing the supply of renewable energy, and decreasing the demand for fossil fuels. UDFB would become a model of renewable energy and waste reduction at the neighborhood level. In summary, the anaerobic digester would:

a)    Reduce UDFB’s food waste costs

b)    Reduce pollution by not hauling food waste and avoiding methane emissions from decomposing food waste that sits in large fields.

c)     Advance bioenergy that recovers renewable resources like water and organic matter.

d)    Provide increased community resilience via renewable energy production and food security.

Explain how the impacts will be measured:

To evaluate the digester’s effectiveness, we will measure:

Food Waste

-        Pounds of food waste diverted to digester from waste-stream (which usually goes to Cedar Grove composting facility),

-        Type of food waste used (X % meat, X% vegetables, etc.)


-        Cubic feet of RNG produced per week

-        Amount of electricity generated per day/week


-        Pounds of compost produced per week


-        Carbon emission reductions of not having to haul away X pounds of food waste

-        Methane emission reductions of preventing food waste from rotting in landfill (for other facilities where food waste is not composted)


-        Cost-savings of diverting waste (cost reductions of not hauling away food waste in garbage trucks)

-        Cost-savings of producing compost (rather than purchasing from a 3rd party)

-        Cost-savings of producing electricity/gas

Total amount requested from the CSF: $35,000
This funding request is a: Grant
If this is a loan, what is the estimated payback period?:


Budgest Estimate
ItemCost per ItemQuantityTotal Cost
Anaerobic biomethane system w/ 13kw power output1740001174000
Digestate Storage & Fertigation Tank10000110000
Health & Safety Equipment6001600
Transportation (Flatbed Truck Fees/Mileage)131111311
Biodigester equipment120011200
Material Handling/Heavy Equipment7001700
Permit Fees750017500
Anti-acids/Microbial Community175011750
Electricity/Gas Utility Codes320013200
Project Manager5001500
Volunteer Coordinator4001400
Laboratory Fees3001300

Non-CSF Sources:

Funding Options
SPU Waste-Free Communities Matching Grant15000
Boeing ECF Grant40000
Anonymous Donation50000
Neighborhood Matching Fund100000
Project Completion Total: $210,000


Project Timeline Estimate
TaskTimeframeEstimated Completion Date
Finalize custom design of on-site anaerobic digestion systemNovember-December 2018December 2018
Community outreach (find volunteers and raise awareness about project)November-December 2018December 2018
Collect supplies/materials for buidling anaerobic digesterNovember-December 2018December 2018
Permit AcquisitionNovember 2018-January 2019January 2019
Build anaerobic digesterJanuary-April 2019April 2019
Safety/Efficiency AssessmentsApril-May 2019May 2019
Train/Hire youth internsApril-May 2019May 2019
UW Educational Partnership begins (incorporate digester into curriculum)May-June 2019June 2019
Community Workshops beginMay-June 2019June 2019