Circular Sanitation: Source Separation and Urine Diversion

The concept of separating human urine to recover nutrients and water has recently received much attention as one approach of circular economy in sanitation. Over the past decade, interest in urine diversion has grown significantly, spurring extensive research into its treatment and processing. Several large, multidisciplinary projects have since emerged around the world, aiming to move urine-diverting sanitation systems towards large-scale implementation. While once regarded merely as a component of on-site sanitation, urine diversion is now increasingly seen as a valuable complement to centralised wastewater treatment — one that supports resource recovery and helps prevent water pollution.

This Research Topic will offer a forward-looking snapshot of the evolving role of urine diversion in next-generation sanitation systems. This collection will include a range of studies — from fundamental research into biological or chemical aspects of human urine as a resource to cutting-edge advancements in process engineering and the design of technologies for urine diversion. We welcome both studies focused on the implementation of urine diversion and theoretical assessments such as environmental impact and microbial risk. These studies can also explore the potential effects of introducing urine diversion on existing sewer infrastructure and wastewater treatment plants.

This Research Topic encourages contributions that advance our understanding of urine diversion as an approach for sustainable sanitation. We welcome both fundamental and applied research with an emphasis on nutrient recovery, water recovery, pollutant degradation, and the evaluation of urine diversion systems across different operational scales. Submissions introducing novel methodologies and innovative strategies to enhance the performance, scalability, and sustainability of urine-diverting systems are particularly encouraged.

We seek original research articles, reviews, mini-reviews, methods articles, perspectives, and opinions on topics including, but not limited to:

• Chemical, biological, and physical processes occurring within urine-diverting systems
• Technologies for producing safe, high-quality fertilizers
• Advanced approaches for removing or degrading micropollutants and pathogens
• Technical design and optimization of components and integrated systems for real-world implementation
• Impacts of urine diversion on conventional sewer infrastructure and wastewater treatment processes at various scales
• System-level evaluations, including Life Cycle Assessment (LCA) and Quantitative Microbial Risk Assessment (QMRA)
• Assessment of urine-derived fertilizers in horticultural and agricultural applications
• Fate, transport, and persistence of emerging contaminants and microbial pathogens in agricultural systems using urine-derived fertilizers
• Case studies illustrating implementation across diverse geographical, cultural, and socio-economic settings
• Market studies for the commercialization of urine diversion systems

Björn Vinnerås is the president of Sanitation360, Sweden. Prithvi Simha is vice-CEO of Sanitation360, Sweden. Kai Udert is a shareholder of Vuna GmbH and VunaNexus AG. All other Topic Editors declare no competing interests with regard to the Research Topic subject.

Article types and fees

This Research Topic accepts the following article types, unless otherwise specified in the Research Topic description:

• Brief Research Report
• Data Report
• Editorial
• FAIR² Data
• Hypothesis and Theory
• Methods
• Mini Review
• Opinion
• Original Research
• ... View all formats

Articles that are accepted for publication by our external editors following rigorous peer review incur a publishing fee charged to Authors, institutions, or funders.

Article types

This Research Topic accepts the following article types, unless otherwise specified in the Research Topic description:

• Brief Research Report
• Data Report
• Editorial
• FAIR² Data
• Hypothesis and Theory
• Methods
• Mini Review
• Opinion
• Original Research
• Perspective
• Policy and Practice Reviews
• Policy Brief
• Review
• Systematic Review
• Technology and Code

Keywords: Sanitation, Urine, Source separation, Circular sanitation, Green sanitation, Fertilizer, Urea, Ammonia, Urine concentration

Important note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.