Civil war Day 21-PWD-Sewage & house drainage

Front

The lower surface of a sewer is known as

Back

Invert

Answer explanation

The invert of a sewer refers to its lowest internal surface or bottom line, used for hydraulic gradient and level measurement.

Front

The sewer which transports sewage to the point of treatment is called

Back

Outfall sewer

Answer explanation

The outfall sewer carries sewage from the main sewer or pumping station to the treatment plant or point of final disposal.

Front

In the design of storm sewers, 'time of concentration' is relevant to determine the: Rainfall intensity, Velocity in the sewer, Time of travel, Area served by the sewer

Back

Rainfall intensity

Answer explanation

The time of concentration represents the time taken by runoff from the farthest point of the drainage area to reach the inlet; it is used to determine rainfall intensity for design discharge.

Front

Main constituents of gas generated during anaerobic digestion of sewage sludge?

Back

Carbon dioxide and methane

Answer explanation

During anaerobic digestion, organic matter decomposes in the absence of oxygen, producing biogas mainly composed of methane (≈65%) and carbon dioxide (≈35%).

Front

When should a complete thorough treatment be given to sewage before disposal in a stream or river?

Back

Less than 150

Answer explanation

When the dilution factor is less than 150, natural purification in the stream is inadequate, so complete sewage treatment must be done before disposal.

Front

High COD to BOD ratio of an organic pollutant represents

Back

Low biodegradability of the pollutant

Answer explanation

A high COD/BOD ratio indicates that much of the organic matter is non-biodegradable, hence the pollutant has low biodegradability.

Front

A ventilating pipe connected to or close to the outlet side of a trap seal

Back

Antisiphonage pipe

Answer explanation

An antisiphonage pipe is fitted near the outlet side of traps to maintain the water seal by preventing siphonage when fixtures discharge simultaneously.

Front

The pipe which is used to discharge foul gases in drains or sewer into the atmosphere is known as

Back

Vent pipe

Answer explanation

A vent pipe allows the escape of foul gases from the drainage or sewer system into the atmosphere, preventing pressure build-up and trap seal loss.

Front

The pipe that carries discharge from urinals, water closets etc. is termed as

Back

Soil pipe

Answer explanation

A soil pipe carries discharge containing human excreta from water closets, urinals, and similar fixtures directly to the sewer or septic tank.

Front

Sequence of connections for water supply to a house: Stopcock, Goose neck, Ferrule, Water meter.

Back

Ferrule, Goose neck, Stopcock, Water meter

Answer explanation

The correct sequence is Ferrule → Goose neck → Stopcock → Water meter (III, II, I, IV). The ferrule connects to the main, the goose neck provides flexibility, the stopcock controls flow, and the water meter records usage.