Author:
Daly Sarah E.,Usack Joseph G.,Harroff Lauren A.,Booth James G.,Keleman Michael P.,Angenent Largus T.
Abstract
AbstractIn several states of the U.S., one measure to mitigate greenhouse-gas emissions has been to ban food wastes from landfills. As a result, U.S.-based companies are now providing decentralized food-waste management systems for supermarkets and restaurants, which include storage as a slurry. It is unclear, however, which storage conditions (factors) would affect the spontaneous microbial activity, resulting in a different fermentation product spectra, and how this would affect further post-treatment. Here, we performed two experiments to mimic: 1) storage and 2) subsequent anaerobic digestion. For the food-waste storage system, we designed a mixed-level fractional factorial analysis with 12 experimental combinations, including separating food waste into: carbohydrate-rich, lipid-rich, and protein-rich food waste. We found that all factors that we tested correlated with the fermentation product spectra, but that especially the factors: i) storage temperature; ii) food-waste composition; and iii) storage time affected the fermentation outcome. We observed that relatively low pH levels of 3-4, which were achieved due to rapid lactic acid accumulation by microbial activity during storage, coincided with greater lactate production at a maximum chemical oxygen demand (COD) selectivity of 90%. This provides an opportunity to optimize lactate production, which is ideal for subsequent methane or chemical production.TOC/Abstract graphic
Publisher
Cold Spring Harbor Laboratory
Reference46 articles.
1. U.S. EPA (2016) Advancing sustainable materials management: 2014 fact sheet assessing trends in material generation, recycling, composting, combustion with energy recovery and landfilling in the United States (United States Environmental Protection Agency, Washington, DC 20460), (Office of Land and Emergency Management (5306P)).
2. U.S. EPA (2016) Inventory of u.S. Greenhouse gas emissions and sinks: 1990 – 2014 (United States Environmental Protection Agency, Washington, DC 20460).
3. Wasted food, wasted energy: The embedded energy in food waste in the United States;Environ. Sci. Technol,2010
4. The Influence of pH on Hydrolysis and Acidogenesis of Kitchen Wastes in Two-phase Anaerobic Digestion
5. Biochemical methane potential and biodegradability of complex organic substrates