Assessing the environmental impact of energy production from hydrochar generated via hydrothermal carbonization of food wastes. (September 2015)

• Record Type: Journal Article
• Authors: Berge, Nicole D.; Li, Liang; Flora, Joseph R.V.; Ro, Kyoung S.
• Is Part Of: Waste management. Volume 43(2015)
• Page Start: 203
• Page End: 217
• Publication Date: 2015-09
• Subjects: Hydrothermal carbonization -- Life cycle assessment -- Food waste -- Environmental impact; Hazardous wastes -- Periodicals; Refuse and refuse disposal -- Periodicals; 363.728
• DOI: 10.1016/j.wasman.2015.04.029
• Languages: English
• ISSNs: 0956-053X

Abstract

Highlights: Life cycle assessment of the HTC process was conducted using EASETECH. HTC products and hydrochar combustion influence system environmental impact. Emission savings from electricity generated from hydrochar combustion are significant. Liquid streams need to be appropriately managed to reduce environmental impact. Sorting of food wastes from the waste stream reduces the load to the environment. Abstract: Although there are numerous studies suggesting hydrothermal carbonization is an environmentally advantageous process for transformation of wastes to value-added products, a systems level evaluation of the environmental impacts associated with hydrothermal carbonization and subsequent hydrochar combustion has not been conducted. The specific objectives of this work are to use a life cycle assessment approach to evaluate the environmental impacts associated with the HTC of food wastes and the subsequent combustion of the generated solid product (hydrochar) for energy production, and to understand how parameters and/or components associated with food waste carbonization and subsequent hydrochar combustion influence system environmental impact. Results from this analysis indicate that HTC process water emissions and hydrochar combustion most significantly influence system environmental impact, with a net negative GWP impact resulting for all evaluated substituted energy-sources except biomass. These results illustrate the importance of electricity production from hydrochar particularly when it is used to offset coal-based energy sources. HTC process water emissions result in a net impact to the environment, indicating a need for developing appropriate management strategies. Results from this analysis also highlight a need for additional exploration of liquid and gas-phase composition, a better understanding of how changes in carbonization conditions (e.g., reaction time and temperature) influence metal and nutrient fate, and the exploration of liquid-phase treatment.