Various strategies for controlling micropollutants, along with the challenges faced in implementation

Micropollutants, also referred to as contaminants of emerging concern, are substances that have gone unnoticed due to their infinitesimally small concentrations lying between parts per trillion to parts per billion levels. Despite their small concentrations, they have emerged as a threat to ecological biodiversity, food security, and public health. They are majorly classified into five categories, viz., pharmaceutical drugs, polar pesticides, chlorinated kerosene, perfluorinated compounds, and personal care products. The unmonitored discharge of industrial, hospital, municipal, domestic, and agricultural effluents, accidental spills, sewage treatment facilities, sludge accumulation, and leakage from septic tanks are the key contributors to the rising levels of these micropollutants in soil and water. In contrast, micropollutants in the air originate from the toxic fumes released from heavy industries and thermal power plants. However, micropollutants often migrate from air to soil by rainwater and from soil to water by leaching, thus resulting in widespread contamination of water bodies (Das et al. in Sustainable microbial technology for synthetic and cellulosic microfiber bioremediation, pp. 221�238, 2024a), Das et al. (Renewable energy generation and value addition from environmental microfiber pollution through advanced greener solution, p. 278, 2024b); (Mohanty et al. in Sustainable management of urban plastic waste through circular economic approaches, pp. 27�48, 2024a), (Mohanty et al. in Sustainable microbial technology for synthetic and cellulosic microfiber bioremediation, pp. 239�258, 2024b); (Sahu et al. in Sustainable management of urban plastic waste through circular economic approaches, pp. 262�279, 2024). Therefore, it is necessary to develop methods to eradicate micropollutants at the source or the first stage of environmental contamination. However, the infrastructure for removing micropollutants from air and soil is yet at the research stage, and the infrastructure to treat water bodies is seemingly incapable of completely removing micropollutants and primarily focuses on treating heavily contaminated wastes. The removal of micropollutants thus requires the implementation of tertiary treatment techniques encompassing biological, physical, and chemical treatment methods. The first part of the chapter reviews the existing strategies for the control and removal of micropollutants and the recent developments in the removal strategies. In the second part, the operational details of the existing treatment processes, typical process efficiency, and the challenges involved in the development of suitable infrastructure for the commercial implementation of these techniques are elaborately discussed. At last, future perspectives for removing micropollutants at the source, strategies to prevent their migration from one environmental body to another, and scope for developing necessary infrastructure are provided.