Grantee Research Project Results
Final Report: Anaerobic digestion for a zero waste urban campus
EPA Grant Number: SU839284Title: Anaerobic digestion for a zero waste urban campus
Investigators: Lishawa, Shane C. , Monks, Andrew , Ryan, John , Erickson, Kevin , Tomerlin, Mary , Dever, Monica , Spehn, Nicole , Niosi, Olivia , Baranovskis, Patrick , Reese, Victoria , Waickman, Zach , Zhu, Zhenwei
Institution: Loyola University of Chicago
EPA Project Officer: Page, Angela
Phase: I
Project Period: October 1, 2017 through October 31, 2018
Project Amount: $14,999
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2017) RFA Text | Recipients Lists
Research Category: P3 Awards , Sustainable and Healthy Communities , P3 Challenge Area - Air Quality
Objective:
We worked to create a carbon-neutral and zero-waste model for urban campuses that reduces emissions and solid waste disposal by producing energy for heating and electricity from campus organic waste via Anaerobic Digestion (AD). Specifically, we achieved the following research objectives: 1) quantified the anaerobic methane production potential (MPP) of all organic campus waste streams individually and in combination and determined optimal waste stream mixtures for solid waste reduction and energy production; 2) built four benchtop-scale continuous flow AD systems and investigated loading rate and retention time of our optimal waste stream mixture 3) evaluated the quality of AD digestate for secondary utilization as an agricultural soil amendment and sustainable landscaping fertilizer.
Summary/Accomplishments (Outputs/Outcomes):
Our project engaged ten undergraduate students within Loyola University Chicago's Institute for Environmental Sustainability (LUC-IES) in student-led research projects related to generating biogas from campus waste streams via AD under the tutelage of five faculty advisors. LUC-IES provided an interdisciplinary learning experience by engaging students in research including: chemically analyzing campus wastes; characterizing sewage sludge from the Metropolitan Water Reclamation District (MWRD); determining the energy-producing potential of campus waste products through three, 30 day experimental runs on an Automatic Methane Potential Test System II (Lund, Sweden); analyzing the chemistry of spent waste products post-digestion; analyzing plant growth of two crops on two soils fed with four concentrations of spent digestate over a 40 day period; and designing, feeding, and maintaining four flow-through digestion systems fed by two waste combinations over 60 days. This work culminated in several poster and oral presentations including N. Spehn and O. Niosi presenting our results at the 2018 National Science and Engineering Expo.
Through three MPP experiments, our team characterized the biogas production ability of eight campus-generated organic waste streams including three combinations of food waste from LUC-IES' student cafe, four biodiesel waste products, and woody biochar. Students conducted the tests in triplicate samples on a 15 x 500mL reactor apparatus that included an automatic gas counter to measure the volume of methane produced (results in Table 1). Students found all feedstocks and combinations were appropriate for AD, with biodiesel waste products producing the most methane. These results are encouraging to any facility producing organic waste, especially where fuels are produced and energy-dense oils can be fed into AD systems.
Using feeding rates and blends consistent with our MPP experiments, students also analyzed gas production and performance of four two liter continuously fed AD systems. Where our MPP reactors were fed just once, our scaled-up reactors were fed every other day, with spent digestate removed before feedings, more closely mimicking a full scale AD system. We fed the digesters organic matter in two different blends: food waste, and food waste with biochar. We monitored gas production, reactor pH, and volatile solids to determine reactor health. The reactors fed with food waste alone quickly became acidic and halted microbial activity and biogas production, whereas the food waste plus biochar reactors produced biogas throughout the experiment. As predicted, the biochar addition buffered the pH of the reactors, allowing consistent gas production throughout the experiment.
Finally, we ran a 40 day growth experiment of two common crops (rye grass & lettuce) grown in two soils (sandy blend & on-campus blend), fertilized with liquid digestate from our AD systems at dilutions of 0% (control), 1%, 10%, and 100%. We found a linear increase in above and below ground plant biomass of both crops in both soils as fertilization rate increased (R 2 : 0.81 for rye; R 2 : 0.74 for lettuce). Chemical analysis revealed that digestate was rich in phosphorus and nitrogen. These results show that spent digestate is a viable fertilizer for landscaping and growing food.
Conclusions:
This project has shown that various on-campus organic wastes including food waste, biodiesel waste, and biochar, are valuable substrates for AD the bioproducts of which can be subsequently used as a soil amendment. These results illustrate the potential for this technology to divert waste on campuses worldwide, collegiate or otherwise.
Journal Articles:
No journal articles submitted with this report: View all 3 publications for this projectSupplemental Keywords:
Anaerobic Digestion; biogas; green energy; sustainable development; clean technologies; innovative technology; waste reduction; waste minimization; biochar; nutrient recycling; agricultureRelevant Websites:
Institute of Environmental Sustainability Exit
Institute of Environmental Sustainability - Biodiesel Program Exit
I.E.S. Ecological Restoration
Research Group Exit
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.