Is Urine Source Separation the Environmentally Preferred Option for Wastewater Management? Insights from a Life Cycle Assessment Study

This study evaluates the environmental impact of hybrid wastewater treatment systems, which combine decentralized urine treatment with a highly efficient centralized WWTP with low nitrous oxide (N2O) emissions and electricity use. The comparison is made against the impact of the same centralized WWTP treating mixed wastewater. The results show that the hybrid scenarios showed a lower impact than the baseline in marine, freshwater eutrophication and marine, freshwater ecotoxicity. However, all the hybrid scenarios presented a higher global warming impact than the baseline scenario. A sensitivity analysis on direct N2O emissions and centralized WWTP electricity use shows that while urine source separation is not preferred to a highly efficient WWTP, it can be used to improve the global warming impact of less efficient WWTPs.