Artificial wetlands and floating islands: Use of macrophytes

Abstract

Constructed wetlands, including floating islands, are a suitable technology for wastewater treatment. They are low cost and respectful with the environment, which is why they are significantly beneficial for agricultural irrigation systems. One of the limiting factors in structuring efficient constructed wetlands is the choice of plant species that can tolerate and eliminate contaminants. Macrophytes have an important role, since they allow their filtration, retention and absorption, among other processes. The objective of the work has been to show the diversity of emergent and aquatic species used for the treatment, highlighting species such as Typha latifolia, Typha doingness and Eichhornia crassipes, as species of constant use. In efficiency, they manage to eliminate nutrients and organic matter in excess, as well as toxic elements such as zinc, cadmium, lead, chromium, mercury, among others, in values between 15-95%. Some studies also address emerging pollutants, showing that wetlands successfully mitigate the presence of contamination by these micro-pollutants, eliminating paracetamol, ibuprofen, caffeine and antibiotics, among others, in values of 75-99%. Constructed wetlands are a frequent management practice for the mitigation of pollutants, the management of the biomass generated is an issue little explored and rarely considered. It is important to highlight several works where biomass is used to feed animals, such as fertilizers, to generate building blocks and production of bioenergy through biogas.