WorksheetsDay 30_LSGD_Public health- Terms, systems of sanitation
Total questions: 15
Worksheet time: 8mins
The term “self-cleansing velocity” in house drainage refers to —
The minimum velocity at which suspended solids just start settling
The minimum velocity that prevents deposition of solid matter
The maximum permissible velocity in sewers
The theoretical velocity of design storm flow
The “anti-siphon trap” is primarily installed to —
Increase discharge capacity of the trap
Prevent loss of water seal due to negative pressure
Reduce odour transmission by water curtain
Facilitate mechanical cleaning of blockage
The pipe which conveys foul gases from the drainage system to the atmosphere above roof level is the —
Soil pipe
Waste pipe
Vent pipe
Anti-siphon pipe
In a single-stack system of house drainage, the trap ventilation is —
Provided at every floor
Provided only at the terminal branch
Provided through a separate vent stack
Not separately provided
The connection between the house drain and public sewer is made through a —
Cascade chamber
Retention chamber
Intercepting chamber
Vacuum relief chamber
A disconnecting trap is provided —
At every floor waste
At the junction of house drain and municipal sewer
Below each closet trap
At every gully trap location
Which arrangement provides the highest degree of protection against foul air?
Partially ventilated single stack
Fully ventilated system (two-pipe system)
Anti-siphon system
Single stack system
In a high-rise multi-storey drainage design, vent pipe diameter is kept not less than the diameter of branch pipe mainly to:
Reduce negative pressure
Maintain gradient
Comply with trap sizing
Ensure hydraulic continuity of air column
The minimum gradient of 1 in 50 in branch drains is recommended mainly for:
Reducing noise
Increasing flow
Ensure self cleansing velocity
Gaining invert level
The pipe carrying discharge from water closets (WC)s is called (a) .
The pipe carrying liquid waste from baths/kitchens is called (a) .
The pipe carrying foul gases upward is called (a) .
What percentage of wet weather flow is considered as dry weather flow?
(a)
A parallel vertical pipe balancing stack pressure is (a) .
Write down the main diasdvantages of dry conservancy system
(a)
