Fats, Oils and Greases to Biodiesel: Technology Development and Sustainability Assessment
Fats, Oils and Greases to Biodiesel: Technology Development and Sustainability Assessment A dissertation submitted to Department of Biomedical, Chemical and Environmental Engineering Division of Graduate Studies University of Cincinnati In partial fulfillment of the requirement for the degree of DOCTORATE OF PHILOSOPHY 2015 By Qingshi Tu B.E. in Environmental Engineering, University of Shanghai for Science and Technology, 2008 M.S. in Environmental Engineering, University of Cincinnati, 2012 Committee: Mingming Lu, PhD (Chair) Tim Keener, PhD Ting Lu, PhD Drew C. McAvoy, PhD Raymond Smith, PhD Abstract Fats, oils and greases (FOG) in the wastewater stream have long been a nuisance to the environment because they clog sewer pipes, causing overflows and damages. FOG can be classified as trap grease if obtained directly from food services, or sewer grease if mixed with FOG in the sewer system. This dissertation evaluated the technical feasibility and several sustainability parameters of converting trap/sewer grease into biodiesel. This waste-to-energy practice can provide the dual benefit of waste reduction and biofuel production. Monte Carlo simulations were conducted to model the energy consumption and GHG emissions from trap grease-to-biodiesel production life cycle at a wastewater treatment plant. Results were highly dependent on both the trap grease properties (e.g., FOG concentration, free fatty acid (FFA) concentration, etc.) and the utilization of non-lipid fraction of the FOG. Trap grease can provide lower energy consumption and lower GHG emissions for biodiesel production when compared to other feedstocks. This is particularly true for the trap grease with high FOG concentrations, low FFA concentrations, and a high performance anaerobic digestor (AD).
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