Industrial ecology of symbiosis is a concept generated out of collaboration and inter-firm exchange of by-products and collocation of the industrial units within same area. The core theory of symbiosis is the mutual and profitable coexistence and environment-friendly sustainable development with an emphasis on preservation and reuse of scarce raw materials and natural resources. The principal aim is to ascertain its efficacy for sustainable development of the region to preserve and recycle resources for mutual benefits of the units as well as society as a whole.
Evolution of "industrial symbiosis" at Kalundborg, Denmark is a favorite case study for the industrial ecologists. ‘Over the last 20 years in a small industrial zone on the coast, 75 miles west of Copenhagen Kalundborg Industrial park evolved.’ [Indigo Development consulting company, (online) Available from <URL: www.indigodev.com> from the online page http://www.indigodev.com/Kal.html] The key component or constituent of industrial symbiosis is to work together in order to reach a distinct solution. In the symbiosis concept, the by-product generated by one company is consumed or is an important channel for any other or more than one company interconnected in the park. The final result is a significant reduction in the consumption of scarce resources and diminution of adverse environmental impact. The cooperation of different units increases efficiency without straining resources like energy water and other raw materials. This can be achieved by following methods, namely, in case of by-products using innovative ways so that they can be commercially viable for the company, or use by-products in an ingenious mode through a new inventive operation.
In Kalundborg industrial symbiosis three major areas are focussed namely, conserving water, saving energy and integrated waste management. The flow of materials and energy among companies (and with the community) has developed over the last 25 years in this small industrial zone. The symbiosis was started when Gyproc in 1970 located its facility in Kalundborg. It was done to take advantage of the butane gas which the refinery was burning and was made available from Statoil since 1972. The gambit of exchange of industrial wastes and other materials between companies and for the welfare of the communities has not only reduced cost but also transformed industrial wastes as a good source of income as was noticed by the plant managers and the residents of that area. This was having a great deal of impact on the environment on which till date they were unaware.