Abstract Anticipating nutrient pollution under changing conditions is urgent for water security. Nonetheless, high-resolution predictive frameworks capturing nonlinear driver responses remain limited. Here, we present a nationwide assessment of China’s water-quality evolution from 2023 to 2100, integrating over 3 million daily records with 41 climatic, landscape, and socioeconomic drivers via regionally tailored Random Forest models ( R 2 of 0.88–0.92). Our results reveal a disruptive spatiotemporal shift, with projected NPI ranges from –50.9% to +218.1% under SSP5-8.5. Seasonal patterns restructure toward unimodal peaks, with pollution increases in spring/autumn (up to 28.3%) but decreases in summer (up to 27.0%). Spatial homogenization emerges via a westward/southward shift of pollution centers, with localized increases exceeding 200% from coldspots with low baselines (<0.4 vs >1.0 in hotspots). Landscape configuration dominates (64.5% feature importance) over climatic forcing (7.2%–35.5%), reinforced by minimal climatic projection uncertainty. Strategic land-use planning could be a cornerstone of future water security.

Artificial intelligence (AI) algorithms are increasingly recognized for their transformative potential in water regulation and management. This systematic survey reviews 100+ peer-reviewed studies that applied AI-driven techniques to advance water policy across three critical policy domains: water pollution, drinking water, and infrastructure regulation. Using a novel multi-dimensional evaluation framework, this systematic review assesses the methodological rigor, policy integration, real-world applicability, AI assurance, and the socioeconomic or ethical impact of each reviewed study. The results reveal that AI applications in water governance are primarily dominated by machine-learning and neural-network methods, focusing on pollution control and infrastructure optimization. In contrast, far fewer studies employ causal, reinforcement-learning, or decision-support approaches that directly engage with policy evaluation. Despite technical advancements, only 18% incorporated assurance elements such as explainability, fairness, or trustworthiness, underscoring the need for more transparent and deployable AI in water governance. This review synthesizes global research efforts and outlines key opportunities and challenges. In response, it outlines future research directions that emphasize policy-aware decision-support systems, the advancement of trustworthy and explainable AI assurance frameworks, and the systematic incorporation of socioeconomic and ethical considerations to strengthen accountability and equity in water governance.

Electromagnetic field (EMF) treatment is a promising nonchemical strategy for scale control in reverse osmosis (RO) desalination; however, the mechanisms by which it influences polymorph selection and competitive precipitation in multi-ionic waters remain poorly understood. Here, we present the first detailed temporal analysis of scale formation, elucidating how EMF alters CaCO₃ and gypsum scaling in multi-ionic, Mg-bearing brackish groundwater (Mg/Ca = 0.67). Without EMF, aragonite and Mg-calcite co-precipitated, consistent with Mg²⁺-mediated inhibition of calcite growth. EMF accelerated bulk crystallization, amplified Mg²⁺ suppression of calcite, and drove an almost complete shift toward aragonite precipitation while maintaining elevated Mg/Ca ratios. EMF also mitigated gypsum scaling by promoting early, uniform CaCO₃ precipitation, reducing free Ca²⁺ availability, and delaying gypsum nucleation during initial concentration stages. At high gypsum supersaturation, precipitation occurred under both EMF and control conditions; however, EMF produced more porous and loosely adherent gypsum deposits. This dual effect—favoring aragonite formation and delaying or modifying gypsum deposition—resulted in more uniform, easily removable scaling layers. Although short-term flux improvements were modest, these mechanistic shifts enhance long-term membrane performance and cleanability, particularly when combined with hydraulic flushing.

Global freshwater scarcity and degradation demand reconceptualizing wastewater as a resource within circular economy transitions. This review utilizes the resource-stack model and treatment-train design space to evaluate wastewater valorization, assessing recovery of water, energy, nutrients, carbon, and trace elements. It examines barriers, inefficiencies, costs, regulatory gaps, and societal resistance and highlights that aligning innovation with policy and governance can transform wastewater systems into infrastructures supporting water security and climate resilience.

Abstract This study presents a life cycle assessment (LCA) of a scaled-up photoelectrocatalytic (PEC) oxidation system for wastewater treatment, modelled using computational fluid dynamics (CFD). The system used a BiVO 4 /TiO 2 -GO photoanode for solar-driven degradation of micropollutants. The LCA assesses energy use, resource demand, and emissions to evaluate the system’s sustainability in line with EU wastewater regulations. Compared to a full-scale ozonation plant in the Netherlands, the PEC system shows superior environmental performance during operation and end-of-life phases, despite higher construction impacts. Solar energy use and potential material reuse drive these advantages. A comparison with theoretical pilot-scale oxidation technologies from literature adds depth, though the study acknowledges limitations such as micropollutant variability and wastewater complexity. Overall, the findings highlight PEC oxidation’s promise as a sustainable and effective approach for micropollutant removal in water treatment.

Abstract A sustainable strategy for sewage nitrogen recovery via mainstream NH4 + exchange combined with side-stream partial nitrification (PN) inherently creates a side-stream environment with co-existing high salinity and nitrite. However, the molecular/ionic mechanisms underlying their synergistic suppression of nitrite-oxidizing bacteria (NOB) remain poorly understood. This study demonstrates that 3.3 g/L salinity with >0.06 mg N/L free nitrous acid (FNA) synergistically and selectively inhibited NOB, initiating stable PN within 17 days. This synergy suppressed NOB activity completely and selected out NOB effectively for ~50 days by overcoming the adaptive revival of NOB. Mechanistically, salinity approaching the isotonic point facilitated transmembrane uptake of FNA and protons, enhancing intracellular FNA accumulation and H+-induced bacteriolysis. Differentially, under the synergistic stress, the activity of ammonia-oxidizing bacteria (AOB) increased by 292%, driven by the enrichment of Nitrosomonas. Based on nitrogen balance analysis, microbial evolution and Nir activity changes, Nitrosomonas was found to establish a protective metabolic loop of nitrite reduction to NO / NO reoxidation to nitrite with assistance of denitrifiers to resist the salinity-enhanced FNA inhibition. This study provides an in-depth insight into the role of salinity and FNA in shaping evolutionary trajectories of AOB and NOB, offering a novel framework for sustainable nitrogen recovery in sewage treatment.

The current study evaluated the innovative application of membrane distillation crystallization (MDCr) for dual treatment and resource recovery from acid mine drainage (AMD), a persistent environmental crisis in South African. This AMD was characterized by exorbitant concentrations of Ca2+ (2622 mg·L−1), Fe2+ (1421 mg·L−1), SO42−(9790 mg·L−1) and Cl− (1113 mg·L−1). The current study evaluated the performance of hollow fibre polypropylene membrane in processing both acidic (pH 3.58) and neutralized (pH 6.47) feedwaters. The permeate was 3.3 kg·m−2·h−1, 2.2 kg·m−2·h−1 and 1.3 kg·m−2·h−1 at 70, 60 and 50 °C respectively, which remained relatively stable at high recovery factors ( >80%). Acidic AMD promoted formation of large metal-rich ettringite and halite crystals while neutralized AMD produced small and dense ettringite, hexahydrite and jarosite crystals. This study highlighted the dual functionality of MDCr in water treatment and mineral resource recovery, offering a sustainable solution to address the AMD pollution crisis in South Africa.

The study focused on identification of Internet of Things (IoT) solutions that can be used in the management of non-revenue water (NRW) in water distribution networks (WDN). The review show that water utilities incur significant revenue losses due to NRW emanating from leaks, illegal connections, and non-payment of water bills. The uptake, adoption, and deployment of IoT solutions can contribute to the realization of new products and services, sustainable development solutions, transformation, and enhanced decision-making, in the water sector. Overally, IoT solutions can help water utilities improve operations and management of WDN and minimize NRW, which aligns with the anticipated impact of the study on contributing to and enhancing the realization of resilient smart cities. Finally, the novelty of the study is to demonstrate the potential of translating theoretical innovations and technologies into industrial/ practical applications and commercialization.

This study investigates the synthesis of ZrOx-loaded NiFe2O4 photocatalysts (1, 2, and 3 wt%) through co-precipitation and wet impregnation methods for environmental and health applications. The structural analysis revealed a cubic crystal structure, with ZrOx doping enhancing charge separation and mobility by converting the morphology from fibrous to needle-like. Under visible light (VL) and H2O2 activation, the ZrOx(3 wt%)/NiFe2O4 composite achieved high degradation efficiencies (98.5% for Bisphenol A and 98.2% for 4-Nitrophenol) in 120 min via the Photo-Fenton mechanism. Kinetic analysis showed pseudo-first-order behavior with rate constants of 0.945 min−1 for BPA and 0.904 min−1 for 4-NP. The catalyst demonstrated stability with 91.5% efficiency retention after multiple cycles. DFT calculations indicated favorable HOMO-LUMO alignments and electrostatic potentials. Additionally, ZrOx(3 wt%)/NiFe2O4 exhibited selective cytotoxicity against breast cancer cell lines, while maintaining high viability in HEK-293 cells. The results suggest that ZrOx(3 wt%)/NiFe2O4 composites are promising for environmental and biomedical applications.