This is a Request for Information (RFI) only. This RFI is not accepting applications for financial assistance. The purpose of this RFI is solely to solicit input for ARPA-E consideration to inform the possible formulation of future programs. The purpose of this Request for Information (RFI) is to solicit input for a potential ARPA-E program focused on the development of technologies to recover high energy-value materials from wastewater to reduce energy demands and greenhouse gas (GHG) emissions associated with conventional sourcing and waste stream treatment. Wastewater in this RFI is broadly defined, and includes municipal, livestock, industrial, and mining sources. High energy-value materials under consideration are nutrients (i.e., ammonia and phosphorus) and critical minerals, where the latter are a group of 50 elements in the periodic table including lithium and rare earth elements (REEs). To view the RFI in its entirety, please visit https://arpa-e-foa.energy.gov.