Using Aquatic Plants and Plant Material for a Sustainable Water Purification Creating Low Impact Development Systems

Phytoremediation and the use of living plants to clean up soil, air or water from hazardous contaminants is well known as a cost-effective approach to take advantage of the abilities of plants to take up compounds and metabolize them in their tissues. However, the practical use of plants and associated microorganisms can lead to an external metabolization of compounds giving possibilities in generating even more toxic metabolites. Recently we demonstrated the successful use of systems only containing rootless aquatic plants for the remediation of cyanobacterial toxins, as well as veterinary pharmaceuticals such as oxytetracycline and methyltestosterone. These Low Impact Development Systems, we called “Green Liver Systems” in analogy that plant have the same or very similar biotransformation systems like our own human liver. Our research showed that using the natural functions aquatic macrophytes can provide in taking up and metabolizing various contaminants from water is beneficila to the environment. The Green Liver Concept showed that the metabolites are than stored within the plant in vacuols, apoblasts and also included in cell walls. In order to make Green Liver System multi-functionable and suitable for the removal of microplastics as well, we developed additional filter systems using dead plant material such as coconut fibers, luffa pads, jute fibers, cotton pads derived from used t-shirts having a recycling idea in mind and biochar derived from Finnish spruce trees. Applying microplastics (spherical beads 2-10mm, cylindrical particles (1-5mm) and fleece fibers) on the different plant material showed a retention between 75 % - 96 % (spherical beads), 100 % zylindrical particles and 100 % fleece fibers. The overall performance of the newly developed LID System was tested using Diclofenac in combination with spherical microbeads (microplastics) showing that 85% of the Diclofenac could be removed from the water phase and 99% of the MP as well.