Heavy metal assessment in vineyard sludge. Copper lixiviation and recovery studies.

L. YOHAI; GARRIDO MOLINA, CLAUDIA; RESINA GALLEGO, MONTSERRAT; LÓPEZ MESAS, MONTSERRAT; VALIENTE, MANUEL

Atenas

Conferencia; 18th International Conference on Environmental Science and Technology; 2023

Global Network of Environmental Science and Technology jointly with the University of the Aegean (Greece) and the National and Kapodistrian University of Athens (Greece).

The use of copper-based compounds to prevent fungi diseases in vineyards have contributed to copper (Cu) accumulation in soil, vegetation and waste, causing a serious environmental and agro industrial problem (EFSA, 2013). In this concern, one of the main issues is the waste generated both during and after wine production. This waste must undergo through aerobic/anaerobic digestions, so a safe disposal is possible. As a result, a main final sludge waste is generated. This sludge is characterised by the presence of significant nutrients for soil fertilisation and regeneration, so the return of sludge to vineyard soils would provide a sustainable solution for this waste. However, its hazardous Cu content (and zinc (Zn) as a concomitant residue) hinders its use in soils. The risk associated to its use, does not depend on the total heavy metal content but to the retention phases and metal speciation present in the sludge, which will determine the mobility and bioavailability of the metals.The use of sewage sludge in agriculture has increased in the last decade in the European Union (EU), with a usage rate of more than 40% (Mackie et al. 2012). The sludge may only be used in agriculture in accordance with Directive (86/278/CEE)(European Commission 1986) and in order to achieve the EU guidelines on healthy soils and adaptation to climate change for 2030 (European Commission 2021).In this work, Cu and Zn availability assessment is determined by applying sequential speciation methodologies(Wang et al. 2022) to determine both the risk associated with the use of this sludge as a soil improver and fertiliser, and the metal distribution in the sludge phases (operational speciation) to accomplish for a most appropriate and environmentally safe treatment process for its use. Also, Cu and Zn recovery processes is presented to provide a Circular Economy solution.