Designing a circular economy model from the olive mill waste

A sustainable system is characterized, inter alia, by a much reduced use of inputs and by the reuse and recycling of material outputs (waste is considered a resource and resources have to be maximised within the system). Hence, a circular economy model that moves towards the closing loop also suggests a drastic reduction or elimination of waste and dissipative loss. The present paper focuses on an useful concept of waste and by-products within the agro industrial system, based on the perspective of circular economy. This approach can be achieved through efficient small and industrial scale bioenergy plants, biorefineries and environmentally friendly processes for the production of biomolecules to be employed as active principles in many sectors. In particular, the case study of this paper concerns the exploitation of an olive-oil by-product (wet-pomace) as a new source of energy and polyphenol compounds on an industrial scale. The paper aims to design a technical and economic model of a platform which produces bioactive compounds from the Olea by products, in particular from wet pomace, an olive-oil mill waste, which usually represent a disposal problem. By the application of the MFA methodology (Material Flow Analysis) to the production process, the authors provide a case study about the implementation of this kind of multifunctional platform in a region in southern Italy, where the cultivation of Olea europaea L. and the production of virgin olive oil are widespread. The regional level has been chosen, because the local approach allows for avoiding and/or reducing the economic and environmental cost of the waste transport. The recovery of chemicals and the production of energy should be a continuous process of interaction between high technology and environmental and economic sustainability, making this kind of platform highly innovative and consistent with the principles of the circular economy, as well as with the development of a new business. The results have highlighted that this platform can produce up to 6000 kg of enriched polyphenol fractions, generating an approximate income of over 155,000 Euros; moreover, each residue of the process (water, olive stones, destoned pulp) comes into a new use in the same and/or external processes according to the circular economy. The conclusion underlines the main positive features of this sustainable model, in particular the eco-innovation of the process and the economic and environmental advantages consisting in reducing waste, water and energy consumption.