Which pump type is referred to as a disintegrating pump because it macerates or breaks up solids in sewage before discharge, thereby reducing clogging risk?

Introduction / Context:
In wastewater collection, solids such as rags and fibrous materials can clog pumps. Some pump designs incorporate macerating (disintegrating) mechanisms so solids are shredded before being conveyed through the volute and discharge piping.

Given Data / Assumptions:

• Pumped medium: raw or screened sewage with potential rags and fibrous solids.
• Objective: minimize clogging by breaking solids before or at the impeller.
• Disintegrating pump implies an integrated cutter mechanism.

Concept / Approach:
The term “disintegrating pump” in many sanitation texts refers to a centrifugal pump fitted with cutter teeth or a macerating head at the inlet. The rotating cutter shreds solids so the impeller can pass the slurry without blockage. This differs from positive-displacement pumps whose valves or tight clearances may trap solids, and from pneumatic ejectors that avoid impellers entirely but do not “disintegrate.”

Step-by-Step Solution:
1) Identify which option includes an actual disintegration mechanism at pump entry.2) Recognize that the macerator-equipped centrifugal pump is designed to shred solids.3) Conclude that this is the pump described as “disintegrating.”

Verification / Alternative check:
Manufacturers’ literature for sewage macerator pumps shows integral cutter/impeller assemblies specifically marketed to prevent ragging and clogging in lift stations.

Why Other Options Are Wrong:

• Reciprocating pump: Uses valves with small clearances; prone to clogging by rags.
• Pneumatic ejector: Moves sewage by compressed air but does not shred solids.
• Peristaltic or air-lift pumps: May handle solids but do not disintegrate them.

Common Pitfalls:
Equating “solids-handling” with “solids-disintegrating” — only macerator/cutter-equipped centrifugal pumps actually shred solids.

Final Answer:
centrifugal pump (with cutter/macerator arrangement)