Urban Symbiosis

In the recent decades, there has been a growing interest in Sustainable Urban Systems and the development of sustainable cities and urban contexts is one of the most important challenges of humans’ future. Within the field of IE a specific branch of research is dedicated to Urban Industrial Ecology (UIE) [57], but it is very difficult to exactly determine the birth of the interest in urban research by the IE scholars: Huang et al. [58] argue that a first idea of “urban symbiosis” was already present in Jacob 1961, while the term “urban metabolism” was coined by Wolman [59] in the 1960s to express how energy and material flow in and out of the city (in analogy with the metabolism of human bodies).
What is certain is that into the domain of UE
While the first terms refer to the implementation of IS in urban systems, Rural Urban Symbiosis is generally related to the study of rural-urban interrelations in the context of Urban Geography not necessarily involving IE principles (with the only exception of Cooke [69] which uses the term “urban–rural industrial symbiosis” for describing the experience of
This characteristic makes US even more complex than IS, because on the one hand public organizations are not involved in market driven processes that could be fundamental for the realization and success of symbiotic exchanges and have an infrastructure system very costly to be changed, on the other hand, private organizations are not used to face the typical mechanisms of public activities and the US strategies may be in competition with their activities [70;