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Why is wastewater disinfected before it is discharged?
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Wastewater is disinfected before discharge primarily to protect public health by destroying any remaining pathogenic bacteria in the effluent. This process is essential to prevent the spread of waterborne diseases in the environment.12
Disinfection serves as the final step in the treatment process before the effluent is released into surface water bodies. Common methods include:1
- Chemical Disinfection: Mixing the effluent with chlorine gas or hypochlorite solutions. Because chlorine residuals can harm aquatic life, a dechlorination step may be required.1
- Ultraviolet Radiation: Using ultraviolet radiation to disinfect the water without leaving behind chemical residuals, making it an increasingly competitive alternative to chlorination.1
By ensuring that pathogens are neutralized, disinfection helps maintain water quality and fulfills regulatory requirements designed to prevent the deterioration of streams, rivers, and lakes.1