Leveraging the water-environment-health nexus to characterize sustainable water purification solutions

Abstract

Chemicals of emerging concern (CECs) pose critical threats to both public health and the environment, emphasizing the urgent need for effective water treatment measures. Yet, the implementation of such intervention technologies often results in increased energy consumption and adverse environmental consequences. Here, we employ a comprehensive methodology that integrates multiple datasets, assumptions, and calculations to assess the human health and environmental implications of removing various CECs from source water. Our analysis of two treatment alternatives reveals that the integration of riverbank filtration with reverse osmosis offers a promising solution, yielding healthier and more environmentally favorable outcomes than conventional sequential technologies. By incorporating context-specific practices, such as utilizing renewable energy sources and clean energy technologies, we can mitigate the adverse impacts associated with energy-intensive water treatment services. This research advances our understanding of the water-health-environment nexus and proposes strategies to align drinking water provision with public health and environmental sustainability objectives.

Fig. 1. Estimated non-cancer and cancer disease burdens associated with source water and drinking water treated via two alternative purification systems.

a Cumulative probability distribution function (CPDF) curves depicting the disability-adjusted life years (DALYs) associated with annual exposure to chemicals in source water (orange curve), drinking water treated by the combination of riverbank filtration and reserve osmosis (RBF-RO) system (blue curve), and drinking water purified by the integration of riverbank filtration and extended treatment (RBF-ET) system (red curve). The dotted vertical lines denote the upper limit of the tolerable disease burden (1.00 × 10^–6 DALYs person^–1 year^–1) as suggested by the World Health Organization (WHO). b CPDF curves illustrating the human health effects of RBF-RO, determined by the total annual DALYs per person exposed. Negative values signify the health benefits acquired upon transitioning from RBF-ET to RBF-RO. The disease burdens were assessed in distinct carcinogenic and non-carcinogenic impact categories based on 10,000 Monte Carlo simulation runs.

Fig. 2. Contribution of each category of CECs to the changes in disease burdens associated with drinking water after continuous treatment series.

a non-cancer disease burden. b cancer disease burden. Each column height represents the cumulative median contribution of each chemical of emerging concern (CEC) category, with error bars indicating the 5th and 95th percentiles based on 10,000 Monte Carlo simulations. Small histograms within each chart illustrate the estimate uncertainties, with column lengths showing mean values and bars representing 95% confidential intervals derived from the same simulations. RBF: riverbank filtration. RO: reserve osmosis. ET: extended treatment. DBPs: disinfection byproducts. PCPs: personal care products. DALYs: disability-adjusted life years.

Fig. 3. Exposure concentrations, human toxicity factors, and cancer burdens of six categories of CECs in drinking water treated via RBF-RO.

The color scale denotes the magnitude of each exposure concentration, toxicity factor, and disease burden, while also highlighting the contributions of exposure concentrations and toxicity factors to the disease burden of each chemical of emerging concern (CEC) in drinking water produced by integration of riverbank filtration and reserve osmosis (RBF-RO). The charts are based on median data sets for each CEC. Note: CECs lacking available data on carcinogenic effects are not included. The chemical number of each CEC is provided in the Supplementary Information. DBPs: disinfection byproducts. PCPs: personal care products. DALYs: disability-adjusted life years.

Fig. 4. Life-cycle environmental impacts of two alternative water treatment systems.

a Contributions of different water treatment processes to 10 mid-point environmental impacts, expressed per cubic meter of drinking water produced over 25 years of operating the combination of riverbank filtration and extended treatment (RBF-ET) as well as the integration of riverbank filtration and reserve osmosis (RBF-RO) systems. The relative size (or absence) of each color illustrates the contribution of the process to each environmental impact. b Performance and co-benefits of RO-related optimization strategies to mitigate marine eutrophication are depicted for the RBF-RO system. Additional details regarding other constituents associated with RO are provided in the Supplementary Information.

Fig. 5. Spatially differentiated electricity generation mix and resultant effects on the environmental performance of the RBF-RO system at a global scale.

a Variation in the electricity generation mix among 136 countries (listed in Supplementary Table 5). The color scale represents the relative proportion of energy sources in each country. b Maps displaying the selected 136 countries, with colors representing the environmental impacts of the riverbank filtration and reserve osmosis (RBF-RO) system implemented in each country. The global maps were generated using QGIS, and the country boundary data is sourced from http://www.naturalearthdata.com/. Supplementary Data 1 provides the complete model outputs.

Fig. 6. Conceptual framework illustrating the interactions among clean water supply, human health protection, and environmental sustainability goals (“WEALTH”).

a Advancements in water purification technologies are critical for addressing increasing demands on water quality and securing access to clean and safe water. The development and integration of innovative technologies in water purification require rigorous piloting and testing, impacting various supporting industries, such as energy and chemical products. These sectors are essential in enhancing quality of life through rapid advancements in products and services. Within this framework, the environment plays a pivotal role by providing ecosystem services that are vital for a holistic approach to water treatment. Environmental outcomes can be either adversely or positively influenced by decisions made by individuals and industries, which in turn rely on natural resources. b The unfolding of a illustrates all bidirectional interactions within the WEALTH framework. displays all bidirectional interactions within the WEALTH framework. It exemplifies how the integration of advanced technologies with ecological processes, such as the RBF-RO system discussed in this study, can enhance the harmony among water quality, human health, and environmental outcomes.