Just as special economic zones are established under special regulations to to facilitate rapid economic growth, so sustainable industry zones are established under stringent environmental regulation as centres of sustainable industrial development. Whereas special economic zones tend to provide exceptions to economic regulations, in sustainable industry zones no such relaxation is permitted.
There is a clear need for sound environmental management on industrial estates. Fortunately, the proximity of industries that cause environmental damage can be turned to advantage. If environmental concerns are integrated into estate development at all stages, cumulative damaging effects can be avoided. For example, permits can be granted to ensure that only compatible industries are allowed to locate in a given area. Estates with sound environmental management include energy efficiency measures, resource conservation, waste minimization, cleaner production and information centres, and preparedness and planning for accidents.
An industrial development in Scandinavia located complementary industries alongside each other, one using another's waste heat, another its products or by-products.
The most advanced estates form a miniature 'industrial ecosystem' in which individual manufacturing processes optimize the consumption of energy and raw materials and the effluents of one process serve as the raw material for another process.
The industrial district of Kalundborg in Denmark is a prime example of industrial symbiosis. For 15 years, industries on the site have exchanged by-products such as surplus energy, waste heat and other materials. In one example, waste heat (in the form of cooling water) from the Asnaes Power Plant provides district heating to houses and buildings in the municipality of Kalundborg.