India's Water Crisis: Millions Sick, NGT Warns

India's water sources are contaminated with toxic chemicals, heavy metals, and harmful bacteria, posing significant health risks. Between 2005 and 2022, the nation recorded over 20.98 crore cases of waterborne diseases. The National Green Tribunal (NGT) has declared that drinking water contamination infringes upon the constitutional right to life.

Given the scarcity of freshwater, which constitutes a mere fraction of Earth's total water supply, recycling and reusing wastewater emerges as a logical solution. This approach is vital for sustaining industrial activities, meeting the demands of a growing population, and supporting agriculture.

Water quality assessment relies on identifying contaminants like pathogens (viruses, bacteria) and chemical pollutants such as excess nutrients and metals. Indicator organisms, primarily E. coli, are used to detect fecal contamination, a primary public health threat. However, modern regulations require stringent treatment targets to ensure the inactivation of various pathogens.

Wastewater treatment encompasses physical, chemical, and biological processes. Methods like screening, coagulation, flocculation, sedimentation, and filtration remove impurities. Disinfection strategies, including chlorination, chlorine dioxide, and ozonation, are employed, each with its advantages and drawbacks, such as the formation of harmful by-products or varying effectiveness against different microbes.