Source separation: Challenges & opportunities for transition in the swedish wastewater sector

[Display omitted] •Source separation functions moderately-well in the on-site sanitation niche.•Blackwater systems in general perform better than urine diversion systems.•Knowledge development and dissemination of this innovation is still low.•Strengthening of R&D, knowledge networks and new organizational models are needed. A paradigm shift to waste reuse has started in the wastewater sector with many experts calling for greater resource recovery, often facilitated by alternative solutions such as source separation. Source separation has been shown to be advantageous for improving treatment capacity, food security, and efficiency; yet these systems are still immature, considered risky by professionals and scarcely implemented. This study attempts to answer the question of why source separation is still marginalized by examining the Swedish experience with source separated wastewater from the perspective of Technology Innovation Systems (TIS) in order to identify obstacles and policy recommendations. Considering that source-separation is still in a development phase, the study found that source separation works moderately well within the on-site niche and that blackwater systems in general perform better than urine diversion. Knowledge development is found to be the weakest function. A major blocking mechanism is the weakness of interchange between knowledge development and entrepreneurial activity. Policy recommendations include: increased R&D; building networks and communication platforms; and establishing guidelines for technologies, legislation interpretation and organizational models.