Converting campus waste into renewable energy – A case study for the University of Cincinnati Qingshi Tu, Chao Zhu, Drew C. McAvoy ⇑ Department of Biomedical, Chemical and Environmental Engineering, College of Engineering and Applied Science, University of Cincinnati, 2600 Clifton Avenue, Cincinnati, OH 45221, USA article info Article history: Received 5 September 2014 Accepted 14 January 2015 Available online xxxx Keywords: Anaerobic digestion Biodiesel Food waste Fuel pellets GHG Waste-to-energy abstract This paper evaluates the implementation of three waste-to-energy projects at the University of Cincin- nati: waste cooking oil-to-biodiesel, waste paper-to-fuel pellets and food waste-to-biogas, respectively. The implementation of these waste-to-energy (WTE) projects would lead to the improvement of campus sustainability by minimizing waste management efforts and reducing GHG emissions via the displace- ment of fossil fuel usage. Technical and economic aspects of their implementation were assessed and the corresponding GHG reduction was estimated. Results showed that on-site implementation of these projects would: (1) divert 3682 L (974 gallons) of waste cooking oil to 3712 L (982 gallons) of biodiesel; (2) produce 138 tonnes of fuel pellets from 133 tonnes of waste paper (with the addition of 20.75 tonnes of plastics) to replace121 tonnes of coal; and (3) produce biogas that would be enough to replace 12,767 m 3 natural gas every year from 146 tonnes of food waste. The economic analysis determined that the payback periods for the three projects would be 16 months for the biodiesel, 155 months for the fuel pellet, and 74 months for the biogas projects. The reduction of GHG emission from the implementation of the three WTE projects was determined to be 9.37 (biodiesel), 260.49 (fuel pellets), and 11.36 (biogas) tonnes of CO 2 -eq per year, respectively. Ó 2015 Elsevier Ltd. All rights reserved. 1. Introduction Universities are the place where knowledge is taught, ideas are inspired and technologies are developed. These activities lead to the consumption of resources, including energy, water, and food, which in turn result in the generation of waste (Alshuwaikhat and Abubakar, 2008; Smyth et al., 2010). A mission of many uni- versities in the US is to promote the idea of sustainability among students, faculty, and the society (Cortese, 2003). Therefore, improving resource management and minimizing waste genera- tion are two key challenges for universities to address in achieving those campus sustainability goals. One solution is to recycle wastes and reuse them on-site for energy production. Converting waste into energy minimizes campus wide waste disposal efforts while at the same time providing the university with energy that reduces GHG emissions from replacing fossil fuels. The on-site implemen- tation of the proposed waste-to-energy options has an additional advantage of eliminating the transportation required for ultimate disposal, which further reduces fuel consumption and associated GHG emissions. This paper evaluates the implementation of three WTE path- ways, namely, waste cooking oil-to-biodiesel, waste paper-to-fuel pellets and food waste-to-biogas at the University of Cincinnati. The selection of these three WTE pathways was based on the goal of leveraging existing infrastructure as well as fitting the best interest for the University of Cincinnati. For example, making waste cooking oil into biodiesel leverages the existing biodiesel production system at UC. The food waste-to-biogas pathway was selected because a reduction in GHG emissions was expected to be higher than composting (Zhu, 2014). In addition, there is an ongoing algae-to-biofuel pilot project that can potentially use the CO 2 in the biogas as carbon source for algae growth. The paper- to-fuel pellets pathway was selected because of its relatively sim- ple manufacturing process and more importantly due to the need to replace coal at one of UC’s utility plant. Biodiesel is a mixture of fatty acid methyl esters (FAME) that are derived from renewable feedstocks such as vegetable oils, animal fats, and waste oil and greases via transesterification (Clements and van Gerpen, 2004; Chai et al., 2014). Biodiesel displays comparable fuel properties with petrochemical diesel fuel, while significantly reducing the emission of most air pollutants and greenhouse gases (GHGs). In http://dx.doi.org/10.1016/j.wasman.2015.01.016 0956-053X/Ó 2015 Elsevier Ltd. All rights reserved. ⇑ Corresponding author at: Department of Biological, Chemical and Environmen- tal Engineering, ERC 740, 2901 Woodside Dr., University of Cincinnati, Cincinnati, OH 45221-0012, USA. Tel.: +1 513 5563952. E-mail address: mcavoydm@ucmail.uc.edu (D.C. McAvoy). Waste Management xxx (2015) xxx–xxx Contents lists available at ScienceDirect Waste Management journal homepage: www.elsevier.com/locate/wasman Please cite this article in press as: Tu, Q., et al. Converting campus waste into renewable energy – A case study for the University of Cincinnati. Waste Management (2015), http://dx.doi.org/10.1016/j.wasman.2015.01.016