Faculty of Natural Sciences

Treatment wetlands (TW) technology is a nature-based solution, where natural processes are optimized to improve water quality. TWs are characterized by relative low establishment costs, robustness, and are easily operated and maintained. According with Brix (2018) “CWs are often considered a more sustainable solution to treat many types of wastewater compared to other more conventional treatment technologies. The role of the plants in CW have been extensively discussed, however, the studies very seldom evaluate the potential of the produced biomass to produce high value products using advanced bio-refining technologies, representing a gap of opportunity for CW technology. The bio refining processes for the production of high value plant-based products have been extensively studied; nonetheless, few studies have been focused in the evaluation of the potential of a biomass coming from TW were plants were part of a wastewater treatment. This study is a first approach to recover high value products from biomass harvested from TW. The study compared the biomass production yields, assessed the sugar species, and proteins for 5 different plant species growing in natural environment vs the same plants used for the treatment of polluted waters in natural based solution (Natural Conditions, NC); to determine the feasibility of the plants to produce cellulose, isolated protein, and biocrude. Additionally the biomass was characterized for the accumulation metal and heavy metal content to evaluate the possible translocation from water to the aerial part of the plant, used to produce isolated protein. The result seems to show that the selected biomass, conformed by the most used TW plants in the world, it is suitable for protein, cellulose, and biocrude production. The protein content was significantly higher in the TW plants than the NC plants. The cellulose production showed a similar tendency. Regarding with the biocrude production, the results showed no differences between the yield obtained in the TW plants than the ones grown in NC. The environmental value of the plants lies on the fact that the biomass from this type of treatments is considered a residual product and up to now, no aggregated value has been found from this low carbon foot print, GHG sinks, effective water treatment. The production of the plant biomass doesn’t require land since they are already in site, nutrients are sufficient for the growth and are uptaken from the influent waters and since they are part of the system. Under this new perspective, TWs can contribute with more sustainable goals, not only the related with the cleaner water production through the wastewater treatment, but also the objective of zero hunger, industry, innovation and infrastructure, and responsible consumptions and production, processing the biomass produced by plants through bio refining process.
However, further studies dealing with primary production of the plants, digestibility of the produced protein, uses of the cellulose and sugar obtained, and composition of the biocrude produced need to be performed to optimize the potential and the quality of the products in the context of the circular economy