The redevelopment of a brownfield: an option of CO2 absorption

The importance of reusing abandoned or idle territory is becoming fundamental because of the lack of building sites and productive land. Different options of territorial recovery exist; in many cases of brownfield redevelopment the project is a reclamation of the site and the construction of other structures or buildings. In this paper we present a kind of recovery that considers the option of restoring the initial ecosystem. We consider a project of reforestation in the landfills of the Santa Barbara mines. These mines, located between the Province of Firenze and Arezzo, were rich in lignite. The excavation of this material has produced a great quantity of sterile land, about 360,000,000 m(3) collocated in landfills close to the mines. In the 1970s a project of redevelopment of this area began with the partial reforestation of the site in order to stabilize the scarps and to make a productive arboriculture. The reforestation was made by the Sperimental Institute for Arboriculture of Arezzo. In this paper we try to evaluate the cost of this operation by means of an environmental accounting methodology, emergy analysis, and environmental advantage in terms of CO2 absorption. The emergy analysis is able to compare the value of human and natural systems on a common basis: the quantity of solar energy directly and indirectly required for a process. This quantity is called emergy and represents the memory of all the energy and matter that the biosphere used up to make a product available. The greenhouse inventory of the operation gives a quantitative measure of the CO2 that has been sequestered in the arboriculture. This type of redevelopment permits definitively the reintroduction of animal and vegetable species and the birth of a new ecosystem.