ABSTRACT
The use of seaweeds in wastewater treatment (WWT) is increasing around the world, being one of the most employed biotic systems to reduce the nutrient eutrophication pressure caused by wastewater. However, the physicochemical characteristics of the seaweeds used in the WWT limit their commercialization. Consequently, this biomass is mainly discharged or used for energy production (where the risk is considered to be low). However, such biomass has the potential to be used by several industries, with an increased value, aiming for a circular economy. Nonetheless, there is a need to develop technologies or methods to guarantee that seaweeds used in WWT can be employed in general uses, to surpass the present bottleneck in biomass recovery.
This chapter shows that seaweeds have a high potential to be used as bioremediation tools in WWT systems, and thus, if possible, the seaweed biomass from WWT (SWWT) must be fully exploited, allowing the implementation of circular economy practices. There is a need to guarantee the quality and safety of the seaweed biomass used in WWT, namely for animal feed, agriculture, subproducts (polysaccharides), or biomass conversion into energy (biomethane and bioethanol). There is an absence of a legal background for the use of seaweed biomass resulting from WWT plants, and thus, efforts are required to ensure the sustainable use of this biomass.
