Our article quantifying the minimum energy to recover nitrogen and phosphorous from various waste streams has been published in Environmental Science: Water Research & Technology.
This study employed the Gibbs free energy of separation to determine theoretical minimum energies required to capture N and P fertilizers from waste streams of fresh and hydrolyzed urine, greywater, domestic wastewater, and secondary treated wastewater effluent. The analysis revealed advantages for nutrient recovery from nutrient-dense streams, such as urine, compared to dilute sources, such as wastewater effluent. The most energetically favorable ammoniacal nitrogen and orthophosphate recovery systems, which target hydrolyzed and fresh urine, respectively, require energy efficiencies >7% and >39% to out-compete energy requirements for conventional methods of nitrogen fixation and phosphate mining. The sizable energy savings and environmental benefits of N and P recovery from waste streams, particularly urine, provide justification to pursue and implement nutrient reclamation systems.
