Technologies for fractionation of wastewater and resource recovery

Wastewater is an underexploited resource that it is globally generated at a rate of 2.2 × 1012 m3 year- 1. Wastewater needs to be treated before discharge in a process that consumes up to 4% of the total energy consumed in a municipality. However, wastewater contains chemical energy in the form of organic compounds (discussed in another chapter) and valuable metals and nutrients (nitrogen and phosphorus), which can be processed and recovered in sustainable processes leading to wastewater revalorization. The objective of this chapter is to provide a comprehensive review of the current state of the technologies in use or under development for (1) metal recovery from wastewater or biosolids through precipitation, sorption, membrane, or electrochemical systems and (2) nitrogen and phosphorus recovery using traditional techniques, like struvite precipitation, or novel, state-of-the-art systems, such as ion-exchange membranes.