Typically, the spent foundry sand is physically processed to remove contaminants prior to reuse in the process. In reclaiming the spent sand, some foundries may route this spent sand through a thermal unit to combust the organic binder material in the spent sand. If the spent sand treated in the thermal unit is a hazardous waste, the thermal unit is considered subject to RCRA Subtitle C and would need a permit. For more information on these requirements, contact your local EPA Regional Office. All hazardous wastes must be treated so that the concentration of hazardous constituents is below a certain level established for each waste.
Treatment is required to minimize threats to human health and the environment.
If fresh metallic iron is regularly introduced into the mixture, then soluble lead can be kept at low levels. However, for example, if the mixture is placed in a landfill and left alone, the iron will oxidize, thereby losing its ability to reduce lead ions. Over the years, several EPA Regions have addressed noncompliance issues at local foundries. For example, in 1995 EPA Region 6 initiated an inspection program to assess waste management practices and the scope of noncompliance with environmental regulations at foundry operations. As a result of its inspections, Region 6, with the support of several states, initiated a program that not only would provide owners and operators with a better understanding of RCRA, the Clean Air Act, and Clean Water Act but also would address specific aspects of these laws applicable to the metal casting or foundry industry.