What process involves the removal of contaminants from water before it is released into the environment?

The process that involves the removal of contaminants from water before it is released into the environment is referred to as treatment. This encompasses a variety of methods and techniques aimed at cleaning water to ensure that it meets safety and quality standards for both ecological balance and public health. Treatment processes can include several steps such as coagulation, sedimentation, filtration, and disinfection, all designed to eliminate harmful substances and pathogens.

Filtration is a specific method used within the broader scope of treatment to physically remove particles and impurities, but it does not represent the entire treatment process. Purification often implies achieving an elevated standard of cleanliness but may not cover all the necessary steps involved in preparing water for safe environmental discharge. Sampling, on the other hand, is the method of taking water tests and does not actively contribute to the removal of contaminants. Therefore, treatment is the most accurate term describing the comprehensive approach to making water safe for release into our surroundings.