Constructed Technosols: A Strategy toward a Circular Economy

Abstract

Soil is a non-renewable natural resource. However, the current rates of soil usage and degradation have led to a loss of soil for agriculture, habitats, biodiversity, and to ecosystems problems. Urban and former industrial areas suffer particularly of these problems, and compensation measures to restore environmental quality include the renaturation of dismissed areas, de-sealing of surfaces, or the building of green infrastructures. In this framework, the development of methodologies for the creation of soils designed to mimic natural soil and suitable for vegetation growth, known as constructed soils or technosols, are here reviewed. The possible design choices and the starting materials have been described, using a circular economy approach, i.e., preferring non-contaminated wastes to non-renewable resources. Technosols appear to be a good solution to the problems of land degradation and urban green if using recycled wastes or by-products, as they can be an alternative to the remediation of contaminated sites and to importing fertile agricultural soil. Nevertheless, waste use requires analysis to ensure the salubrity of the starting materials. Moreover, materials produced on site or nearby minimize the cost and the environmental impact of transport, thus the involvement of local stakeholders in the urban land management must be encouraged.

Management of soil carbon sequestration in urban areas

“…Construction and demolition waste may be re-used together with organic waste for their construction. Technosols are an alternative to importing soil for restoring degraded urban areas (Deeb et al, 2017;Barredo et al, 2020;Fabbri et al, 2021). They have been used, for example, in urban community gardens in New York City (Egendorf et al, 2018).…”

Selected Properties of Soil-like Substrates Made from Mine Coal Waste and Their Effect on Plant Yields

“…A condition for achieving climate neutrality is protecting soils and achieving land degradation neutrality by 2030 [6]. The main actions for soil conservation are to reduce the use of soils for non-agricultural and non-forest purposes, to increase the production potential of poor-quality soils, and to reclaim degraded and devastated soils [7]. These actions, for poor-quality soils, may include enriching them with organic matter and plant nutrients.…”

“…These actions, for poor-quality soils, may include enriching them with organic matter and plant nutrients. On degraded and devastated soils, it is often necessary to restore the soil or cover significant areas with a material that meets the requirements of the soil substrate [7]; research indicates that waste can be used for these activities [8][9][10].…”

From waste to valuable resources: exploitation of mineral waste in civil and environmental application.

“…Thus, it represents a huge quantity of materials to be managed (and recycled). The management of this fraction could pose environmental problems because of its potential contamination from petroleum-derived products or Potentially Toxic Elements (PTE), and the low physical and chemical fertility (Fabbri et al 2021, Molla et al 2021).…”