A review on occurrence characteristics and removal technologies of emerging contaminants in source-separated urine

Source-separated urine is increasingly recognized as a promising resource for nutrient recovery; however, compared with conventional wastewater systems, the occurrence, behavior, and removal of emerging contaminants (ECs) in urine remain insufficiently characterized. Most existing urine-focused reviews primarily address nitrogen and phosphorus recovery or sanitation performance, while ECs are often only briefly discussed, resulting in fragmented evidence across contaminant classes and regions and limiting a coherent urine-centered understanding of exposure patterns and treatment needs. This review synthesizes current knowledge on the occurrence and removal of ECs in source-separated urine, focusing on antibiotics, endocrine-disrupting chemicals, microplastics, and related persistent pollutants. By integrating bibliometric analysis with mechanistic evaluation of representative treatment technologies, we provide a structured overview of research trends, dominant contaminant groups, and key methodological limitations. Critical gaps are identified, including the scarcity of urine-specific datasets, inconsistencies in reported concentration metrics, and insufficient consideration of contaminant fate during urine treatment and resource recovery. The implications of these gaps for safe urine reuse are discussed, highlighting the need for targeted treatment strategies and standardized monitoring frameworks. Overall, this review offers a urine-centered perspective on ECs and provides guidance for advancing safe and sustainable urine resource recovery.