In the early days of manufacturing, the focus
was on minimizing the cost and very little attention was paid to the effects
of such processes on the environment. Today, it is widely recognized that
environmental degradation decreases the quality of life giving rise to
the field of environmental engineering.
The initial concern of environmental engineers was to clean up sites which
had already become polluted. This was usually done by civil engineers with
some participation from chemical engineers.
The new criteria for successful manufacturing is to minimize the environmental effects, in addition to minimizing the manufacturing costs. In other words, the manufacturing process should be designed such that pollution does not occur in the first place. Such designs can only be achieved by chemical engineers, placing them in the forefront of this rapidly emerging field.
This new approach can be illustrated by the redesign of automobiles in the 1970’s to minimize the emission of polluting gases. Automobiles run on hydrocarbons (gasoline and diesel fuel) which are burned in the engine to produce energy. Car engines are typically less than 100% efficient with the fuels undergoing incomplete combustion resulting in hydrocarbons (HC), nitrous oxides (NOX) and carbon monoxide (CO) in the exhaust. Lead, which was a fuel additive, was also present in the exhaust.
The redesign of cars was achieved by requiring them to use lead-free fuels and by the addition of the catalytic converter, which converts the products of incomplete combustion to those corresponding to complete combustion, namely carbon dioxide (CO2), water vapor (H2O) and nitrogen (N2). The converter uses chemical reactions taking place on a honeycombed metal structure, known as a monolith catalyst, for this process.
Chemical engineers are increasing being called upon to develop such innovative solutions to environmental problems. This has provided chemical engineers with exciting new opportunities in a variety of industries. Such opportunities will continue to increase as stricter environmental regulations take effect worldwide.