Project Overview

The CGCC Food Waste Recycling Project is a grant-funded campus-wide ongoing collaborative project that offers deep, cross-disciplinary, experiential student learning via an innovative solution for CGCC’s food and green waste. With the support of campus facilities, this program has established a receptacle system that facilitates separation of food waste generated on campus. A collaborative group of biology and engineering students, with guidance from faculty, have designed a unique organic waste digester machine that will recycle food and green waste into a nutrient-rich liquid fertilizer, which will be used to maintain campus grounds. During this time, students will be studying the effects of this liquid fertilizer on plant life. The long-term goal is for this model to be used throughout the Maricopa Community College District and for this fertilizer to be disseminated to our surrounding agricultural community with city partnerships established by students. Through collaborative biology, art, English, and communications projects, students have begun a marketing campaign that promotes a “sustainability mindset” by changing the behavior of how our campus community handles their waste through increasing awareness of what happens to our food after we dispose of it. CGCC students play an integral role throughout this project, which offers a unique opportunity to practice translational science, bringing innovative ideas to the public while fostering critical thinking and confidence in their innovative potential.


The CGCC Food Waste Recycling Project was transformed from a passionate idea inspired by college students showcasing their projects during CGCC’S Annual Sustainability Day event in April 2017 for 160 third graders to a 2018-2019 Maricopa Center for Learning and Instruction (MCLI) grant-funded campus-wide initiative in just the span of one year. The Food Waste Recycling Project is a multidisciplinary endeavor. To bring a project of this size to life requires many areas of expertise and participation by full time and adjunct faculty and staff from a wide variety of departments. A main facet of this program is to provide students with a unique opportunity for collaborative, experiential, theoretical, and practical learning opportunities through tasks associated with the program. Within the first year, the program has already become well integrated into campus life.


  • Provide problem-based, authentic learning opportunities to students: students will participate in projects that directly impact their community and have real-world application. This type of problem-based learning experience has been shown to positively impact students’ sense of ownership in the knowledge and success of the project. This project will foster critical thinking and confidence in student innovative potential.
  • Economic and workforce development in Arizona: challenging students who participate in the program to perform tasks they will also perform in their careers, such as writing grants, marketing, research, experimental design and execution, and collaborations between specialties. Experience in performing these types of tasks will give these students confidence once they enter the workforce, helping to produce leaders and innovators in our community.
  • Build an organic waste recycler machine that will process food and green waste producing a nutrient-rich liquid fertilizer.
  • Attain recognition as an innovator among higher education institutions: To our knowledge, the use of an aerobic digester machine to recycle food and landscaping waste is not being utilized in Arizona, therefore the Food Waste Recycling Project places CGCC at the forefront of sustainable innovation.
  • Expand beyond CGCC campus: The final long-term intent for the liquid fertilizer produced via the CGCC organic waste recycling program is that it will be distributed to our local agricultural community essentially replacing or reducing their reliance on conventional chemical fertilizers.
  • Change the behavior of the CGCC community: Influence students, faculty and staff to separate their food waste by providing a 3 bin receptacle in the cafeteria and posting instructional posters on how to sort waste.


Team members:

  • Dr. Yvonne Reineke (Residential Faculty: English)
  • Dr. Miriam Kleinman (Adjunct Faculty--Biology)
  • Bassam Matar (Residential Faculty: Engineering)
  • Charlie Poure (Retired--Facilities Manager)
  • Kanapathipillai Prabakaran (Adjunct Faculty: Mechanical Engineering)
  • Joshua Doddroe (Manager, Building Operations)
  • Jay Linford (Environmental Technology Center Technician)

Contributing team members:

  • Dr. Patrick Williams (Residential Faculty: English)
  • Dr. Mickey Marsee (Residential Faculty: English)
  • Mary Beth Burgoyne (Residential Faculty: Library)
  • Trina Larson (Project Manager, Administrative Services)
  • Raquel Gonzalez (Marketing Manager)
  • Markus Fossett (CGCC Coyote Cafe: Director)

Stakeholder involvement and breadth of impact:

In the summer of 2018, shortly after being awarded the MCLI grant, a collaborative team of full-time and adjunct faculty, facility operations, food service, library staff, marketing, and media services began developing and organizing student projects, timelines, and goals. This included creating pre- and post-assessments to measure an “entrepreneurial mindset” in students, creating a survey to measure “sustainability mindset” of campus population, and other cross disciplinary curriculum planning. The Food Waste Recycling Project was presented in a Fall Day of Learning workshop to educate campus staff/faculty on the program and potential collaborations.

Monthly staff and faculty meetings brought together Engineering, Biology, and English faculty, facility directors, and other campus operations personnel to set expectations around the design and implementation of the food digester machine. While other aspects of the Food Waste Recycling Project were able to take place independently, the food digester machine required a coordinated, multidisciplinary effort to allocate the budget, establish the machine’s capabilities, and determine expertise and resources needed for construction, while keeping student learning at the forefront.

Through semester-long assignments, students engaged with different classes depending on the task assigned. This experience creates a community-based learning opportunity through cross-disciplinary teams of biology, engineering, English, facilities, and the CGCC library. Students have been directly involved in tasks such as designing and building the food waste digester machine, creating marketing posters and videos, grant writing and field studies, with future involvement in chemical analysis, presentations at local and national conferences, and public relations.

In the Fall 2018 semester, 3-bin waste receptacles were deployed in the Coyote Café and the campus coffee shop, allowing the campus community to participate in the program each day. The cafeteria staff also contribute by separating the food waste generated during food preparation. Biology students collaborated with the Marketing Department to create posters and flyers that are displayed in the cafeteria and around campus to educate the CGCC community about the program and encourage participation in waste sorting. Posters were displayed near collection bins around the Coyote Cafe, and informational flyers were distributed throughout campus with the goal to engage the campus community and encourage participation in waste sorting.

The facilities staff performs daily collection and delivery of the food waste to the campus garden. Biology students then sort, weigh, and traditionally compost this food waste. Tracking the contamination, by weighing the food waste before and after sorting out non-food waste, will hopefully show an improvement over time in the waste sorting behavior of the campus community. The food waste was “traditionally composted” while the digester was designed and constructed. With this method, the food waste is layered with hay that is inoculated with fungus and bacteria to help break down the food waste. Analyzing the scope of the food waste problem and understanding the behavior around food waste on campus helps students determine techniques to modify behavior of campus community by increasing awareness to reduce contamination.

English students have conducted sustainability and food waste awareness surveys among the student body and campus community. These surveys assess current recycling behaviors, beliefs around food waste, and attitudes on these topics. The surveys are continually evaluated to target areas for future sustainability projects or awareness events with repeated surveys planned to assess progress on behavior change and attitude shifts.

Engineering and biology students collaborated on creating multiple design options for the organic waste recycler machine, based on the concepts of a washing machine, a garbage disposal, and a beer brewing machine. In Fall 2018, biology students conducted experiments to determine the aerobic microbes that produce the enzymes needed to break down food and green waste in the digester machine. In Spring 2019, engineering students presented their 3-D modeled designs and explained the engineering construction steps to a panel of reviewers from various campus departments (including Dr. Peterson, CGCC President). The final design was selected by combining the best elements of two student models. The machine is unique in its two-step process using a single barrel design: first the waste is mechanically blended into liquid form, and then an aerobic microbial digestion process breaks down the food waste to be less than 70 microns in size. Because of this unique design, the process is quick, only taking a matter of hours to complete, and the machine is easy to use. The resulting liquid fertilizer is easy to integrate into campus landscaping operations. Engineering students began construction by creating a 3-D CAD rendering of the design in SolidWorks, and 3-D printed a small scale version of the machine. Next, students procured the materials and constructed the full-size digester machine. The machine was completed at the end of the spring 2019 semester, incorporating the bacteria recommended by the Biology class.

In Spring 2019, biology students conducted quality comparison studies on “organic recycled fertilizer vs standard chemical fertilizer”. Before the food digester machine was complete, biology professor Miriam Kleinman created a “test batch” of the organic liquid fertilizer in the lab to conduct experiments on plant growth. Students applied this liquid fertilizer sample on four varieties of plants, and tested the effects against a control group and a traditional chemical fertilizer group. The overall results were encouraging, with the pea plants responding best to the organic liquid fertilizer.


Spring 2017:

  • Project idea sparked: CGCC’s annual Sustainability Day, where college students showcase their interdisciplinary sustainability projects to local third grade students, inspired Biology faculty member to begin developing the Food Waste Recycling Project.

Spring 2018:

  • Grant application planning: Biology adjunct faculty member and English residential faculty member met with the Maricopa Center for Learning and Innovation directors to discuss the grant application process.
  • Grant awarded: The newly developed “Food and Green Waste Recycling Program” was awarded a $10,000 grant from the Maricopa Center for Learning and Innovation, which funded the first phase of this project.

Summer 2018:

  • Fall 2018 semester project development: Faculty met with a collaborative staff team to organize first semester student projects, timelines, and goals.
  • Workshop presentation: Food and Green Waste Recycling Program presented in a workshop during the Day of Learning to educate campus staff/faculty on the program and potential collaborations.

Fall 2018:

  • “Sustainability mindset” surveys conducted: In September, English students conducted the first round of surveys to measure the “sustainability mindset” of campus population, analyzing the behaviors and beliefs around recycling and food waste.
  • 3 bin waste systems deployed in campus cafeteria and coffee shop: Facilities management collects food waste every day and brings it to the campus garden to be composted.
  • Educational posters and flyers distributed on campus: Posters and flyers were designed by biology students, with the help of marketing department, to educate the CGCC community about the new 3 bin waste collection systems in the cafeteria and the overall food waste program.
  • Food waste collected and analyzed: Biology students, in collaboration with the Environmental Technology Center and Facilities management staff, switched off the daily task of weighing, sorting, and traditionally composting the food waste.
  • Pre-design of food waste digester machine: Engineering students began the pre-planning research of food waste digester by conceptualizing the design and materials needed.
  • Microbial research and selection for the biotransformation process: Biology students determined the specific bacteria strains needed for the food digester machine.

Spring 2019:

  • Food waste collected and analyzed: Facilities management and biology students worked in partnership with the Environmental Technology Center to collect, sort, weigh, and compost the food waste collected daily from the campus cafeteria and coffee shop.
  • Follow up “sustainability mindset” surveys conducted: In February and April, English students conducted follow up surveys on the “sustainability mindset” of the campus population, to assess beliefs and behaviors around food waste and recycling.
  • Design of the food waste digester: In February, Engineering students presented their 3-D modeled designs to a panel of reviewers from various campus departments and the winning design was selected.
  • Construction of the food waste digester: One group of engineering students developed the final 3D rendering in SolidWorks and assembled the full size components. A second group 3D printed a small scale version of the machine. The final machine was completed in May.
  • Organic fertilizer effects analyzed: Biology students conducted quality comparison studies of “organic recycled fertilizer vs standard chemical fertilizer” on different plant species.
  • Innovation of the Year awarded: CGCC won the Maricopa Community College Innovation of the Year Award for the “Food and Green Waste Recycling Program: An Ongoing Collaborative Project Model for Sustaining Student Learning, Success, and Creativity Through Experiential Learning”. One project is selected each from all of the colleges in the district, and the winner receives the Dr. Paul M. Pair Innovation of the Year Award of $2,000 for future innovation.
  • Sustainability Day presentations: In April, engineering and biology students hosted presentations and activities demonstrating the digester machine and food waste recycling, educating fellow CGCC students as well as local elementary students about the Food Waste Recycling Project during this annual CGCC event. Engineering students presented the digester machine, the 3D rendering video, and 3D printed small-scale model at this event. Biology students demonstrated proper food waste sorting practices, and spread awareness about the impact of food waste on our environment. The 3-bin waste collection systems were used during this event, as a pilot test for food waste collection at future college events.
  • Food digester machine pilot tested: In May, engineering students completed construction of the food digester machine and tested it for the first time on campus. They combined food waste, water, and the selected bacteria strains, heated the mixture for six hours, and ended up with a successful first batch of liquid fertilizer.
  • Featured at local innovation fair: At the end of May, CGCC is hosting a Chandler Chamber of Commerce special engagement, “Update from Washington”, attended by US congress members and local businesses. The Food Waste Recycling Project will be featured as an innovative project representing the spirit of the college.

Future plans:

  • Daily food waste processing in the digester machine: Starting fall 2019, the digester will be housed in the on campus garden (Environmental Technology Center). Facilities will bring the food waste collected on campus to the garden each day, where a student worker will sort and process the food waste in the digester machine, storing the liquid fertilizer product to be used in campus groundskeeping.
  • Improvements to digester machine: Engineering students will further enhance the digester machine for ease of use, better filtration, and faster processing.
  • Improvements to the liquid fertilizer formula: Biology students will use the liquid fertilizer produced by the food digester to study its effects on campus plant life. Students will test different formulations and work with the digester to further refine the liquid fertilizer formula, with the possibility of creating specialized formulations for different plants.
  • Chemical analysis of liquid fertilizer: Chemistry students will analyze the liquid fertilizer for its qualitative content, including nitrogen and phosphate levels, giving students experience in chemical composition analysis.
  • Establish community partnerships: Students in various disciplines (English, Business, Biology) will begin researching partnerships with local agricultural businesses to use our fertilizer. This will give students an opportunity to explore the legal, business, and logistical requirements that future students will then use to establish and build beneficial community partnerships.
  • Food waste collection at events: Food waste collection bins will be expanded for use at other college events, demonstrating this project at a broader scale and promoting CGCC sustainability culture. Students will be available during events to spread awareness about the food waste project and encourage participation in waste sorting.


The first phase of this project was grant funded by the Maricopa Center for Learning and Innovation, part of the Maricopa County Community College District, who is dedicated to supporting and advancing teaching and learning by working collaboratively with faculty, administrators, and district-wide groups to provide quality services, programs, and resources. At the start of the project, funds were allocated as follows:

Total Grant: $10,000

  • Faculty compensation: $4,200
  • 3 bin waste receptacles (2 systems): $1,000
  • Educational poster printing and video production: $500
  • Organic waste recycler machine development supplies: $2,500
  • Aerobic Digestion Microbes: $500
  • Student Worker - Spring 2019: $1,300

At the end of its first year, the Food Waste Recycling Project was awarded the Maricopa Community College Innovation of the Year, receiving $2,000 toward future innovation. Leftover funds from the original grant, along with the newly awarded funds, will contribute to funding the next steps including upgrades to the food waste digester machine. Students and faculty members are working on future grant applications that will fund other aspects of this project, such as expanding faculty involvement to other academic disciplines for a greater interdisciplinary student experience.

Future cost savings:

Food waste and landscaping waste typically accounts for approximately 25% of a college campus waste stream and is the heaviest component. By recycling food and landscaping waste we will reduce the amount of waste the campus generates, therefore reducing the cost of waste removal. Additionally, crops and green spaces using fertilizers produced by food or landscaping waste have shown to utilize less water. An excellent example of the cost saving effects of this approach was demonstrated at Harvard, where using a fertilizer created from campus landscaping waste saved the University $45,000 annually in food and green waste removal and fertilizer costs while reducing irrigation by 30%.


This program provides a unique opportunity for collaborative, experiential, theoretical, and practical learning for our students. In the first year of the program, which encompasses the Fall 2018 and Spring 2019 semesters, the project has produced a number of valuable outcomes:

  • The food and green waste digester machine was designed and constructed as a result of detailed planning by Engineering and Biology faculty and students, with input from committee members. Unlike other methods of recycling food waste, like traditional composting or anaerobic digester machines that take weeks or months to recycle food waste, the student-constructed aerobic digester machine uses a mechanical and aerobic microbial breakdown process that will be able to process food and green waste within hours, making it extremely efficient and allowing for the expansion of the program outside of the CGCC campus. The resulting nutrient-rich liquid fertilizer will then be used to nurture CGCC green spaces reducing fertilizer costs and reducing irrigation costs.
  • By placing easy to use 3-bin receptacles for easy sorting of food waste, recyclable waste, and landfill waste in the cafeteria, posting instructional posters and videos around campus on how to sort waste, and raising awareness of the organic waste recycling program, the CGCC community have become more conscious of their behavior around sorting food waste. This fosters the sustainability mindset and reduces the amount of landfill waste CGCC produces. Further design modifications and research will be done by subsequent classes to improve waste sorting and participation.
  • “Sustainability Mindset’ survey research was conducted by English classes, as well as integrated research on recycling best practices and the psychology of food waste bin design and human behavior. Pre- and post-assessment of the “sustainability mindset” on the CGCC campus has been analyzed. While survey results have not significantly changed over the first year, it established a baseline for student and staff willingness to sort their waste and their knowledge of its importance. Behavior changes will be tracked in the surveys and in food waste analysis.
  • Campus food waste sorting behaviors were tracked by monitoring the rate of contamination (missorted waste) and weight of food waste collected. A total of 1,370 lbs of food waste was diverted from the landfill during the 2018-2019 school year. In the spring 2019 semester, there was a 37% contamination rate measured in the food waste collected from cafeteria bins. This will be monitored as future classes implement behavior change strategies.
  • Comparative field studies demonstrating superior crop yield using our organic liquid fertilizer compared to industry standard chemical based fertilizers showed encouraging results, with the pea plants responding best to the organic liquid fertilizer.
  • With research guidance from the Library, Biology students worked in groups to complete two grant proposals that were used to apply for future project funding. Through this experience, students learned the hard work and detail that goes into the grant writing process. As the program continues to expand and develop, students and staff from many disciplines will be able to participate and benefit from this unique opportunity.
  • Biology students were assessed on their “entrepreneurial mindset”: how confident they are on their ability to solve problems, work within multidisciplinary teams, and bring new innovative ideas to their community. Their results were compared to the same assessment given at the beginning of the semester to show the true impact of this active learning experience. Results demonstrated the greatest increase in personality skills of persistence and interpersonal sensitivity.

Lessons Learned

The multidisciplinary nature of the project presented challenges and learning opportunities among the collaborative team. In order to implement the individual components of the project, the team had to establish roles and coordinate logistics between the campus departments and faculty members, as well as external stakeholders who could provide resources. Timing had to be adapted with the understanding that certain pieces of the process will move slower in an institutional setting. When discussing the design and construction of the digester machine, the engineering team used common language to communicate across areas of expertise. The scale and complexity of the machine had to be adjusted based on the current student capabilities and resources available. The team reached the agreement that the first phase of the project would produce a pilot version of the food digester machine in order to prove the concept, which provides a stronger case for large scale expansion. Ultimately, the team kept student learning at the forefront of the process, and utilized the strengths of the engineering students to produce a successful pilot version of the food digester.

The food waste collection and sorting process demonstrated that it takes time and consistent effort to establish a “sustainability mindset” on campus. The process started with students creating educational posters that accompanied the 3-bin waste sorting systems. By physically sorting out non-food items from food collection bins, students started to develop the next steps needed to decrease contamination rates, while avoiding getting discouraged in the process. In order to embed good habits deeper into the CGCC population, we will turn to leadership for support in expanding awareness. This will include a marketing campaign that will establish an identity around composting, and using new student orientation to promote the project and recognize its achievements so far. The goal is to teach the entire campus community about the importance of food waste recycling and how to support our efforts.

Replicability: The efficiency of the digester supports our longer-term goal of expanding the Food Waste Recycling Project beyond the CGCC campus to create more fertilizer that will be used to nurture city green spaces and the surrounding agricultural community. This model could then be adapted at other colleges, beginning their own pilot designs working across relevant programs and implementing them, increasing creativity and efficiency by adding other design inputs to fit the particular college’s sustainability goals, students’ majors, particular culture, programs, and campus strategic vision. Establishing a food and landscaping waste recycling program throughout the Maricopa Community College District and nationally would allow each campus to not only divert their green waste from the landfill, but to also nurture their green spaces all without leaving campus. The feasibility to recycle food and green waste on-site is demonstrated by WisErg, who has their food waste-recycling machine at various grocers and businesses in the California area. This major growth will also provide unique opportunities for CGCC students. The students will be at the forefront of educating the community on how to incorporate organic waste recycling into everyday life, along with interacting with community and city leaders to form partnerships that will expand the program.



Food waste in biodigester

Food waste in biodigester

Photographer credit: Michael Lucas