WaterProof Factsheet: Acidic Deep Eutectic Solvents for the Recovery of Critical Metals from Waste and Wastewater (English)
Year: 2025
Type: article
Abstract: What is wastewater and why does it have to be treated? Wastewater (or sewage) is water that has been used and contaminated by human activities. These activities include everything from household waste like bathwater, dishwater and toilet flushes to industrial and agricultural effluents. In the European Union, 544.4 million population equivalents (p.e.) of wastewater are generated every day. This is an amount that equals around 1087 million bathtubs.1 In order to avoid pollution to the environment, urban wastewater needs to be treated before discharge. Wastewater treatment takes place at specialised facilities known as wastewater treatment plants or sewage treatment plants. They are usually located near urban areas, in order to treat wastewater generated by the surrounding population. Local or regional governments, like municipal water departments, are usually responsible for treating wastewater. In some cases, private companies are hired to run these plants. They have to follow standards and guidelines that are set by regulatory bodies at the state or national level. In the European Union, the Urban Waste Water Treatment Directive (UWWTD)2 regulates how wastewater is collected and how it has to be treated. Although there are still differences in the efficiency of wastewater treatment between the individual European countries, in the EU already 82% of wastewater is treated according to this legislation1. 2 Wastewater treatment is a complex process that involves different treatment stages (see Information Box 1) to purify wastewater before it is reused or released back into natural water bodies. During the treatment process, a solid by-product is obtained, consisting of the solid particles present in the wastewater and of biomass produced within the biological treatment process itself. This solid by-product, or sludge, can be further treated by digestion, to partly convert the organic content into biogas. The biogas can then be used as a (local) source of energy or, after further treatment, supplied to the gas grid. The remaining sludge still contains a mixture of carbon and nutrient rich materials, with small amounts of (precious) metals such as zinc, cobalt, copper, gold, silver, platinum, palladium and rhodium. These precious metals enter urban wastewater streams when the products which contain the metals, e.g. catalytic converters in cars, metal-coated roof materials, food and food-additives, cosmetics (make-up) and medical products, are used and washed into drains, e.g. by rainwater or routine washing. Wastewater treatment is a crucial process for: removing contaminants from sewage and industrial effluent, ensuring the protection of human and animal health and the environment, e.g. by preventing harmful, i.e. toxic, algal blooms, gaining clean drinking water, recovering resources for reuse. This factsheets provides information on how ADES can contribute to the recovery of cirtical metals and how this approach is practiced in the EU-funded WaterProof project.
Authors: Schwarzenberger, Anke, Banduka, Dusica
Language: English
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
Funder: European Commission
OpenAlex ID: W7082645089
FWCI:
Cites:
Cited by:
Related to: