Management of Salt Cake Generated at Secondary Aluminum Melting Plants by Disposal in a Controlled Landfill: Characteristics of the Controlled Landfill and a Study of Environmental Impacts

The production of secondary aluminum and the management of solid wastes by a Spanish company are reported. Ibérica de Aleaciones Ligeras, Ltd., IDALSA, is a Spanish refinery devoted to the production of special alloys of aluminum coming from the recycling of byproducts of this metal. It has set up several clean technologies in its production process in attempts to reduce the emissions and wastes generated by this process. In the case of solid wastes, after a reassessment process controlled disposal in a landfill is used, according to the criteria established in current Spanish legislation. The requirements of the disposal of hazardous wastes in landfills are described, taking into account the geographical situation of IDALSA and the characteristics of the surrounding environment. Aspects such as geology, hydrogeology, and topography are considered. The study of the environmental impact of the landfill consisted of the identification of actions that might be potentially harmful to the environment. Thus, the construction, operation, and sealing and restoration phases of the landfill were differentiated, and in each of these phases the effects on the natural environment and on the economic and social context were borne in mind. Several aspects were considered as criteria for the assessment of impact. The value calculated for each criterion, defined as the degree of intensity of the alteration produced, was used to identify and quantify the environmental impact of the landfill considering all the aspects involved. Quantitative assessment of the environmental impact of the landfill afforded numerical values of between 25 and 53, indicating that the disposal of salt cakes from IDALSA in a controlled landfill has a compatible-moderate impact on the environment.