- A Biological degradation of organic matter using activated sludge
- B Removal of suspended solids by settling and screening
- C Chlorination of treated water before final discharge
- D Addition of coagulant chemicals to settle out solids
Correct answer: B. Removal of suspended solids by settling and screening
Explanation: Primary treatment of sewage involves physical removal of suspended solids through screening and sedimentation.
Concept context
Microorganisms in food, medicine, sewage treatment, biocontrol, and biofertilizers