Advancing the circular economy in informal settlements: An integrated multicriteria assessment of nutrient recovery technologies under uncertainty

Transitioning towards a nutrient circular economy in Colombia, as many regions in the Global South, requires technologies capable of operating under the realities of decentralized and peri-urban wastewater systems, where infrastructure limitations, variable influent characteristics, and economic constraints frequently undermine conventional treatment approaches. Selecting appropriate Nutrient Recovery Technologies (NRTs) for these contexts requires decision-support tools that integrate technical, environmental, and economic performance while explicitly accounting for data uncertainty. This study applies the Methodology for Integrated Multicriteria Decision-Making with Uncertainty (MIMDU) to evaluate and rank NRTs. To address data variability and gaps in the gray literature on emerging technologies, 11 multi-dimensional criteria were weighted by an expert elicitation panel convened at the 18 th IWA World Conference, prioritizing technical robustness (54.0%) over economic (26.8%) and environmental (19.2%) considerations. Results show that Adsorption (distance value 0.1999) is the most stable and cost-effective technology for domestic wastewater with low-nutrient concentration. Other systems rank lower because of maintenance complexity and high capital costs. Overall, this research advances decision-support for the circular bioeconomy by offering a transferable model that can be applied to regions in the Global South to convert incomplete life-cycle data into actionable infrastructure investment strategies.