Benefits and risks of agricultural reuse of digestates from plastic tubular digesters in Colombia. (November 2021)

• Record Type: Journal Article
• Authors: Cucina, Mirko; Castro, Liliana; Escalante, Humberto; Ferrer, Ivet; Garfí, Marianna
• Is Part Of: Waste management. Volume 135(2021)
• Page Start: 220
• Page End: 228
• Publication Date: 2021-11
• Subjects: Biofertilizer -- Biogas -- Low-tech digester -- Anaerobic digestion -- Nutrients recovery -- Manure; Hazardous wastes -- Periodicals; Refuse and refuse disposal -- Periodicals; 363.728
• DOI: 10.1016/j.wasman.2021.09.003
• Languages: English
• ISSNs: 0956-053X

Abstract

Graphical abstract: Highlights: Three digestates from pshychrophilic plastic tubular digesters were evaluated. Nutrients concentration were suitable for agricultural reuse. Heavy metals concentration were suitable for agricultural reuse. Lack of stabilization and pathogens presence represented the main issues. Digestates should be post-treated to improve a safe nutrient cycle. Abstract: The aim of this study is to characterize the digestates from three plastic tubular digesters implemented in Colombia fed with: i) cattle manure; ii) cattle manure mixed with cheese whey; iii) pig manure. All the digesters worked under psychrophilic conditions. Physico-chemical characteristics, heavy metals, pathogens, and agronomic quality were investigated. All the digestates were characterized by physico-chemical characteristics and nutrients concentration suitable for their reuse as biofertilizer. However, these digestates may only partially replace a mineral fertilizer due to the high nutrients dilution. Heavy metals were under the detection limit of the analytical method (Pb, Hg, Ni, Mo, Cd, Chromium VI) or present at low concentration (Cu, Zn, As, Se) in all the digestates. Biodegradable organic matter and pathogens (coliform, helminths and Salmonella spp.) analysis proved that all the digestates should be post-treated before soil application in order to prevent environmental and health risks, and also to reduce residual phytotoxicity effects. The digestate from pig manure had a higher nutrient percentage (0.2, 0.6 and 0.05 % w/w of total N, P2 O5 and K2 O, respectively), but also higher residual phytotoxicity than the other digestates. Co-digestion seemed not to significantly improve the digestate fertilizing potential. Finally, further studies should address how to improve fertilizing potential of digestates from plastic tubular digesters, avoiding environmental and health risks.