Term of Award

Fall 2024

Degree Name

Master of Science, Civil Engineering

Document Type and Release Option

Thesis (open access)

Copyright Statement / License for Reuse

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.

Department

Department of Civil Engineering and Construction

Committee Chair

Stetson Rowles

Committee Member 1

Francisco Cubas

Committee Member 2

Asli Aslan

Abstract

The disposal of food waste (FW) in landfills presents significant environmental and economic challenges, including greenhouse gas emissions and loss of potential resources. Concurrently, the pulp and paper industry, a major sector in the United States, generates substantial quantities of recalcitrant organic waste that is high in lignocellulosic content. Anaerobic co-digestion of FW with pulp and paper mill sludge (PPMS) emerges as a potential strategy to address both waste streams simultaneously, potentially enhancing organic matter degradation and biogas yield. However, the efficacy of this co-digestion approach and its broader sustainability implications remain insufficiently characterized. This study employs laboratory-scale experiments to quantify the digestibility and methane production potential of FW-PPMS mixtures. The results from the lab-scale experiments leveraged a quantitative sustainable design methodology to assess the economic viability and environmental impacts of implementing this process at scale. Factors such as transportation logistics, energy balance, and greenhouse gas emissions throughout the waste management lifecycle were considered for the study. For this sustainability analysis, we considered three baseline scenarios: FW disposal to landfill, PPMS treatment with end-of-life disposal to landfill, and combined treatment with end-of-life disposal to landfill. The specific methane yield from the co-digestion of FW with PPMS was found to be 151 ml CH4/g VS compared to 111 ml CH4/g VS from the mono-digestion of PPMS. The sustainability analysis showed that the food waste to landfill scenario had the highest median daily cost (405.13 USD·tonne-1·day-1) and emissions (556.27 kg CO2 eq·tonne-1·day-1). The combined FW-PPMS treatment scenario resulted in a 42% and 59% reduction in costs and emissions respectively compared to handling FW alone. Finally, the impact of the application context on economic and environmental outcomes was evaluated for different regions in the United States. The Northeast region was estimated to have the lowest median costs (205.57 USD·tonne-1·day-1) and emissions (203.52 kg CO2 eq·tonne-1·day-1) while the Mountain Plains region had the highest median costs (523.96 USD·tonne-1·day-1) and emissions (744.45 kg CO2 eq·tonne-1·day-1). Our analysis reveals that regional factors, especially facility density and location, greatly influence system performance. Overall, this approach of co-digesting FW with PPMS sludge shows promise as an economically and environmentally beneficial waste management solution, though its effectiveness varies by location.

OCLC Number

1478274060

Research Data and Supplementary Material

No

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