Wastewater Management under Global Climate Change Conditions.

Urban wastewater systems were historically designed under assumptions of climatic stationarity; however, climate change is rapidly altering the boundary conditions under which they operate. In this Perspective, we synthesize emerging evidence to conceptualize wastewater systems as climate-responsive infrastructure embedded within dynamic environmental feedbacks. We propose an input-output boundary framework to characterize climate change-driven alterations in wastewater systems. On the input side, climate change affects wastewater systems through three primary pathways: increased flow variability, shifts in physicochemical characteristics of wastewater, and changes in the contaminant spectrum. On the output side, increased risks of untreated discharge or improperly treated effluents and amplified greenhouse gas emissions intensify the environmental footprint of wastewater systems. Collectively, these nonstationary pressures undermine the reliability and effectiveness of key wastewater components, such as wastewater collection networks, biological processes, and advanced treatment units, thereby challenging conventional design and operation. Finally, we highlight four key opportunities of climate-resilient wastewater management, including predictive modeling and adaptive operational strategies enabled by digitalization, resilient infrastructure and process design, decentralized treatment with resource recovery, and nature-based solutions. Reframing wastewater systems as adaptive, low-emission, and circular infrastructures is essential to sustain urban water security under accelerating climate change.