What is a mechanical means to remove material from a sewer?

• A. Brushing
• B. Scraping
• C. Pumping
• D. Sweeping

Answer: (B)

Scraping is the method that directly removes material by physical contact with the surface inside the sewer. It uses a tool or blade to physically dislodge deposits—like grease, mineral buildup, or sediment—from the pipe walls or floor, so they can be carried away by the flow or removed during maintenance. This is why it's considered a mechanical means: it relies on a tangible scraping action to detach material.

Pumping isn’t removing material from the walls; it moves wastewater and any solids it’s carrying. Brushing can loosen some material but isn’t as effective for firmly attached or thick deposits. Sweeping isn’t a practical method inside pipes and isn’t used to remove material from sewer interiors.