Environmental assessment of digestate treatment technologies using LCA methodology. (September 2015)

• Record Type: Journal Article
• Authors: Vázquez-Rowe, Ian; Golkowska, Katarzyna; Lebuf, Viooltje; Vaneeckhaute, Céline; Michels, Evi; Meers, Erik; Benetto, Enrico; Koster, Daniel
• Is Part Of: Waste management. Volume 43(2015)
• Page Start: 442
• Page End: 459
• Publication Date: 2015-09
• Subjects: Ammonia -- Digestate spreading -- Digestate treatment -- Dried digestate -- Flanders -- Life Cycle Assessment; Hazardous wastes -- Periodicals; Refuse and refuse disposal -- Periodicals; 363.728
• DOI: 10.1016/j.wasman.2015.05.007
• Languages: English
• ISSNs: 0956-053X

Abstract

Highlights: Environmental assessment of five digestate treatment technologies using LCA. Environmental benefits observed for treatment of digestate vs. direct spreading. Highest environmental benefits observed when treating raw digestate. Spreading techniques (e.g. injection or incorporation) influence overall impacts. The use of mixing triangles was performed to aid in decision making. Abstract: The production of biogas from energy crops, organic waste and manure has augmented considerably the amounts of digestate available in Flanders. This has pushed authorities to steadily introduce legislative changes to promote its use as a fertilising agent. There is limited arable land in Flanders, which entails that digestate has to compete with animal manure to be spread. This forces many anaerobic digestion plants to further treat digestate in such a way that it can either be exported or the nitrogen be removed. Nevertheless, the environmental impact of these treatment options is still widely unknown, as well as the influence of these impacts on the sustainability of Flemish anaerobic digestion plants in comparison to other regions where spreading of raw digestate is allowed. Despite important economic aspects that must be considered, the use of Life Cycle Assessment (LCA) is suggested in this study to identify the environmental impacts of spreading digestate directly as compared to four different treatment technologies. Results suggest relevant environmental gains when the digestate mix is treated using the examined conversion technologies prior to spreading, although important trade-offs between impact categories were observed and discussed. The promising results of digestate conversion technologies suggest that further LCA analyses should be performed to delve into, for instance, the appropriateness to shift to nutrient recovery technologies rather than digestate conversion treatments.