Thermochemical Treatment of Wastewater Residual Solids for Global Mitigation of Emerging Contaminants

Emerging contaminants are ubiquitous across the environment, posing rising ecological and public-health threats. Through a global data compilation, we show wastewater residual solids, by-products of wastewater treatment, represent a concentrated reservoir of emerging contaminants, capturing an estimated 20%, 24%, and 13% of global releases of microplastics, pharmaceuticals, and antibiotic resistance genes, respectively. This concentration creates a strategic intervention point where eliminating emerging contaminants within wastewater residual solids can substantially reduce environmental loading. Leveraging this opportunity requires next-generation technologies such as thermochemical processing capable of near-complete emerging contaminant destruction. Simulation-based evaluation suggests thermochemical wastewater residual solids management exhibits overlapping cost and greenhouse gas emission ranges with conventional systems, with average costs typically higher and average greenhouse gas emission consistently lower. The Global North faces higher costs yet greater investment capacity, whereas the Global South benefits economically but faces infrastructure gaps. Collectively, this analysis provides insights into intercepting emerging contaminants, reframing wastewater systems as active planetary defenses.