Which option includes disinfection to reduce pathogens before discharge?

Which option includes disinfection to reduce pathogens before discharge?

• A. Secondary Sewage Treatment
• B. Tertiary Sewage Treatment
• C. Wetland-Based Treatment Systems
• D. Septic Tanks

Answer: (B)

Disinfection is the step that inactivates remaining pathogens so the treated water is safe to discharge or reuse. After the initial and secondary treatments reduce organic matter and solids, the effluent can still carry microbes. The tertiary stage adds polishing steps and commonly includes disinfection to meet water-quality standards for discharge into the environment or for reuse. Chlorination, UV, and other disinfection methods are typical in this stage, ensuring pathogens are substantially reduced before release. Secondary treatment mainly focuses on lowering biological oxygen demand and suspended solids with biological processes and does not routinely ensure pathogen destruction. Wetland-based systems provide natural polishing and some contaminant removal but aren’t guaranteed to achieve the disinfection levels required before discharge. Septic tanks perform primary treatment and partial breakdown of waste, but they do not provide reliable disinfection for effluent entering the environment.

Disinfection is the step that inactivates remaining pathogens so the treated water is safe to discharge or reuse. After the initial and secondary treatments reduce organic matter and solids, the effluent can still carry microbes. The tertiary stage adds polishing steps and commonly includes disinfection to meet water-quality standards for discharge into the environment or for reuse. Chlorination, UV, and other disinfection methods are typical in this stage, ensuring pathogens are substantially reduced before release.

Secondary treatment mainly focuses on lowering biological oxygen demand and suspended solids with biological processes and does not routinely ensure pathogen destruction. Wetland-based systems provide natural polishing and some contaminant removal but aren’t guaranteed to achieve the disinfection levels required before discharge. Septic tanks perform primary treatment and partial breakdown of waste, but they do not provide reliable disinfection for effluent entering the environment.