Optimizing Biocrude Production from Food Waste via Hydrothermal Liquefaction

Abstract Description: Over one-third of the food produced in the United States is wasted, leading to resource depletion and environmental harm. Food waste (FW) is the most frequently landfilled and incinerated material, making up 24% of landfilled and 22% of combusted municipal solid waste, contributing to greenhouse gas emissions, climate change, groundwater contamination, and health risks in overburdened communities. While sustainable alternatives for food waste disposal and various food waste valorizations, such as animal feed and biofertilizers, have been proposed, the increasing trend in food waste generation remains a concern. However, biofuel production from food waste presents a promising solution. This study aims to optimize biocrude yield from FW using hydrothermal liquefaction (HTL). Two types of FW—fruit and vegetable waste (FVW) and meat waste (MW)—were analyzed, based on U.S. Department of Agriculture (USDA) data identifying high-loss food groups: apples, strawberries, peaches, grapes, tomatoes, potatoes (FVW), and chicken, beef, and pork (MW), each representing over $1 billion in annual losses. Proximate analysis confirms the suitability of these waste streams for HTL, with high volatile matter content (favorable for biofuel production) and low ash content (minimizing inefficiencies). Preliminary results show that varying FVW-to-MW ratios has minimal impact on HTL product distribution, with liquid yields remaining around 61–62% and solid yields between 2–3%. However, heavy biocrude (HBC) and light biocrude (LBC) yields decrease as MW content declines. Conversely, the aqueous phase (AP) fraction increases as MW decreases, likely influenced by lipid content. Further characterization of the FW feedstocks through ultimate analysis and biochemical composition assessments is ongoing. A predictive model will also be developed to estimate biocrude yields based on FW composition, providing a valuable tool for state and federal agencies to assess the potential of FW as a biofuel resource.