Gestão verde dos resíduos do lagar de azeite: rumo a uma bioeconomia circular

The main aim of OliveBioPath is to design and develop a system based on a CW for the treatment of OMW, with the main goal of reducing the environmental impact of the WW generated and even promoting the circular economy, by recovering the enriched substrate and plant biomass for posterior use as a soil fertilizer in olive groves or in other crops, and the treated WW for land irrigation. In parallel, the valorisation of OP through pyrolysis to produce biochar will also be assessed, as a way to improve the efficiency of the CW. This proposal foresees to achieve a TRL6, that will be made in collaboration with an olive oil company from the northwest of Portugal (the company will provide all the conditions to implement a CW system in the field) and will include a life cycle analysis (LCA) to demonstrate the suitability of its implementation. In fact, this company recognizes the importance of this proposal, giving all their support, since this familiar company has long deal with this issue, and they claim that the present solution which consists of paying a company to collect the OMW, whose destination is unknown, has high costs. Therefore, this project will take a step forward in finding a sustainable solution to this problem and answer the needs of this industry. The RT as already developed in laboratory a small vertical subsurface flow system (TRL 4), based in marshland plants that provided promising results, increasing the quality of the final effluent, reducing OMW toxicity to aquatic organisms and providing a non-phytotoxic substrate. With this project the RT want to improve the lab-scale system and to move to real production conditions. Taking advantage of the existing knowledge and thinking about waste management and circular economy one of the tasks of OliveBioPath (Task 1) foresee the valorisation of other by-product of this industry, the OP, to produce biochar. The biochar will be tested as component of the substrate used in the CW, since several studies have already point for the improvement of CW efficiency regarding contaminant removal, creating optimal conditions for microbial activity and plant growth [16]. Another strategy that will be tested by the RT is the use of a microbial consortium (that will be characterized in Task 3) well adapted to the OMW to boost the performance of the final CW unit. Another important question that the RT want to address is related to the valorisation and reuse of these wastes that have high quantities of value nutrients, organic matter and water. This becomes particularly relevant, considering that the Mediterranean basin is one of the most vulnerable regions of the world to climate change. In fact, near future conditions are expected to aggravate even more the already pronounced economic and environmental difficulties faced by the Portuguese agriculture and other Mediterranean countries [17]. Thus, there is a higher need of increasing crop yields at lower costs and, the importance of controlling soil erosion, improve carbon sequestration (combating climate change), increasing soil organic matter and improving soil structure to promote water infiltration [18] that can be achieved by the incorporation of the CW substrate in the soil. Also, if properly treated the WW can be used for irrigation, reducing the pressure on freshwater resources and tackling the challenge of water scarcity.