Phytoextraction Options.

Wastewaters often contain an array of economically valuable elements, including elements considered critical raw materials and elements for fertilizer production. Plant-based treatment approaches in constructed wetlands, open ponds, or hydroponic systems represent an eco-friendly and economical way to remove potentially toxic metal(loid)s from wastewater (phytoextraction). Concomitantly, the element-enriched biomass represents an important secondary raw material for bioenergy generation and the recovery of raw materials from the harvested plant biomass (phytomining). At present, phytoextraction in constructed wetlands is still considered a nascent technology that still requires more fundamental and applied research before it can be commercially applied. This chapter discusses the different roles of plants in constructed wetlands during the phytoextraction of economically valuable elements. It sheds light on the utilization of plant biomass in the recovery of raw materials from wastewater streams. Here, we consider phytoextraction of the commonly studied water pollutants (N, P, Zn, Cd, Pb, Cr) and expand this concept to a group of rather exotic metal(loid)s (Ge, REE, PGM) highlighting the role of phytoextraction in the face of climate change and finite resources of high-tech metals.