IDENTIFICATION OF MINERAL AND ORGANIC WASTE RESOURCES AS ALTERNATIVE MATERIALS FOR FERTILE SOIL RECONSTITUTION

Abstract

With regard to agronomic and urban soil aspects, difficulties have arisen in recent years concerning the availability of suitable materials for fertile soil reconstitution and tree plantation. Two options for fertile soil reconstitution exist at this time: (i) an excavated and transported agricultural soil; and (ii) a compacted mix of transported soil and stones, providing an adequate bearing capacity for pavements. Both materials - transported agricultural soil and quarry stones - are non-renewable. As a result, the distances over which they must be transported will become increasingly greater, consequently raising their economic and environmental costs. Annual resource availability will thus become increasingly limited, given current trends in urban planning policies. This research programme aims to: (i) identify alternative materials from available urban waste resources; and (ii) propose new options for fertile reconstituted soil by associating a mineral fraction (fine fraction or recycled stones) and an organic fraction (normalised composts). The method is based on an exhaustive inventory of potential waste resources from the European Waste Catalogue (Commission Decision 2000/532/EC of 3 May 2000). This first selection consists of 98 materials (60 mineral or inert and 38 organic materials). The main categories of identified materials are demolition and building materials (rubble and fine fraction), excavated soils, mineral washing residues, dredging sludge, non-toxic industrial residues and normalised composts. The programme will subsequently develop a pedological engineering approach: (i) characterisation of a selection of five to ten materials (individual and mixes); (ii) monitoring and study of parameters that control the evolution from material mixes into a constructed and functional soil; (iii) development of an operational soil construction process. Plante & Cite is a French national technical centre dedicated to landscape and urban horticulture. The aims of this platform are to develop new scientific and technical research programmes and data transfer to green space professionals working within local government agencies and landscape companies.