Question

1. the solid waste produced by a sewage - treatment plant is called ______.

options:

• discharge
• sludge
• runoff
• slime

Explanation:

Sludge is the specific term for the solid waste generated during sewage treatment. Discharge refers to released treated/untreated effluent, runoff is surface flow carrying contaminants, and slime is a thin viscous layer, not the solid waste from sewage plants.

Answer:

C. sludge