ABSTRACT

Recently the protection of the environment has become increasingly important for industry with the requirement that the potential impact on the environment is considered for all aspects of industrial processes. Such considerations are supported by environmental legislation that controls all types of emissions as well as the treatment of wastes. Such legislation is based on global standards that have largely resulted from developments within the European Union, Japan, and the United States in collaboration with international conventions. Of these, the Basel Convention (1989) and the Earth Summit in Rio de Janeiro (1992) were significant in the control and prevention of wastes. In the case of liquid wastes that are most appropriate for treatment by liquid-liquid extraction, limits for discharge into the aqueous environment have been established by the three countries already mentioned. These limits depend on the particular country and sometimes on the industry. (See section 14.6.)

Environmental limits vary according to country, and in the future pressure will be applied to those countries where limits are considered too high. Indeed, there is a general trend for discharge limits to be reduced, with the concept of zero industrial discharge for certain metals being the ultimate aim for the future.