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The resistance of steel to corrosion is obtained with a number of industrial processes based on Zn galvanization. However, all these methods bear a relatively high price tag due to the cost of Zinc plates and electrolytes as well as the formation of hazardous wastewaters containing metals and acids. Wastewaters from Zn galvanization may be grouped into two main types: Mix of Rinse Water (MRW) and Spent Pickling Solutions (SPS). Ordinarily, these waters are mixed and sent for treatment by precipitation. As a result large volumes of galvanic sludge is formed, containing iron, calcium, sulphates and a relatively small quantity of zinc (

Photovoltaic (PV) panels have a crucial role in coping with the global warming mitigation and the energetic crisis currently affecting the European Community. However, from the circular perspective of end-of-life (EoL) management, there are still big issues to be solved in order to recover materials from this kind of e-wastes. Because of several reasons (e.g. type of embedded materials, illegal shipments, location of manufacturers) EoL businesses do not have the interest in approaching them. This poses a significant environmental concern in terms of their management. This work wants to assess the profitability of a specific PV module recycling plant, by evaluating several market contexts in which multiple scenarios of material price, investment and process costs will be considered. The results for a 3000 tonnes plant show that profitability is not verified in the absence of an avoided landfill cost. Instead, when a value of 200 €/tonnes is applied, the net present value is positive in 35.2% of the scenarios and at 87.6% when a value of 350 €/tonnes is considered. The policy choice of this value requires linking the PV module disposal fee to the circular benefits associated with its recovery. [ABSTRACT FROM AUTHOR]

The tanning industry is one of the oldest industries in the world and is known for the production of a wide variety of toxic waste (aqueous and solid) containing chromium salts and other heavy metals. Solid waste is produced during the conversion of putrescible collagen fibres into finished non-putrescible leather products. In this process, the use of a variety of chemicals during the fleshing or trimming phases, results in different hazardous waste, such as wet blue leather, crust leather, chrome shaving, finished leather off-cuts, and unusable chrome spilt. In the present study, we deal with the treatment of these hazardous leather sludge and the recovery of heavy metals contained in them. The leather sludge was pyrolyzed in a torch plasma reactor at a temperature of 1,400- 1,500 °C producing an inert solid residue. However, the high temperatures involved induce the volatilization of some metals, which condense to form hazardous dusts (21.8% Zn, 0.70% Cr, 4,080 ppm Pb and 123 ppm Cd) that have to be properly dealt with. Numerous leaching tests have been conducted to maximize the amount of the individual components solubilized from the powder. Then, different treatment strategies have been combined for the recovery of the main metals: precipitation for Pb and Zn, and adsorption on chitosan for Cd. [ABSTRACT FROM AUTHOR]