Pump selection for deep water table If the static water table is 45 m below ground level, which pump type is appropriate for lifting water from a deep tube well in such conditions?

Introduction / Context:
Pump choice depends on suction limits and submergence. Atmospheric pressure limits practical suction lift for surface pumps, so deep groundwater requires pumps located down the well (or with multistage turbines) to push rather than pull.

Given Data / Assumptions:

• Static water level ≈ 45 m below ground.
• No provision for staging multiple surface pumps.
• Standard well construction for potable supply.

Concept / Approach:
Surface-mounted centrifugal or reciprocating pumps cannot lift from 45 m because maximum theoretical suction lift is about 10.3 m for water at sea level, and practical values are 6–8 m. Deep well turbine or submersible pumps are set below the water level and push water to the surface, bypassing suction limitations.

Step-by-Step Solution:
Compare depth (45 m) to practical suction limit (≈ 7–8 m).Eliminate surface suction pumps (centrifugal/reciprocating).Select deep well turbine or submersible arrangement.

Verification / Alternative check:
Manufacturers’ curves and design manuals specify vertical turbine or submersible pumps for deep tube wells beyond suction capability.

Why Other Options Are Wrong:

• Centrifugal/reciprocating surface pumps cannot sustain suction lift at 45 m.
• “None of these” is wrong because deep well turbine pumps are exactly intended for this case.

Common Pitfalls:
Underestimating suction head losses, vapor pressure effects, and NPSH requirements; always ensure adequate submergence of the bowl assembly.

Final Answer:
Deep well turbine pump (lineshaft or submersible)