1. The trap which is provided to disconnect the house drain from the street sewer is called __________
a) interceptor chamber
b) intercepting trap
c) interception manhole
d) interceptor chamber, manhole and trap
Explanation: A large sewer that receives flow from a number of trunk sewers and transports the flow to the wastewater treatment plant. These sewers do not connect to homes, buildings or street.
2. The diameter of a domestic sewer pipe laid at gradient 1 in 100 is recommended ________
a) 100 mm
b) 150 mm
c) 210 mm
d) 400 mm
Explanation: A sanitary sewer or “foul sewer” is an underground carriage system specifically for transporting sewage from houses and commercial buildings through pipes to treatment facilities or disposal. Sanitary sewers are part of an overall system called a sewage system or sewerage.
Sewage may be treated to control water pollution before discharge to surface waters. Sanitary sewers serving industrial areas also carry industrial wastewater
3. A __________ is a chamber made of concrete, fiberglass, PVC or plastic, through which domestic wastewater, sewage flows for primary treatment.
a) drainage tank
b) pit latrine tank
c) harvesting water tank
d) septic tank
Explanation: Septic tank systems are a type of onsite sewage facility (OSSF). They can be used in areas that are not connected to a sewerage system, such as rural areas. The treated liquid effluent is commonly disposed in a septic drain field which provides further treatment. However, groundwater pollution may occur and can be a problem.
4. The term “septic” refers to ____________
a) anaerobic bacterial environment that develops in the tank
b) refers to safety and precaution
c) drainage of waste materials
d) aerobic bacterial environment that develops in the tank
Explanation: The term “septic” refers to the anaerobic bacterial environment that develops in the tank which decomposes or mineralizes the waste discharged into the tank. Septic tanks can be coupled with other onsite wastewater treatment units such as biofilters or aerobic systems involving artificially forced aeration.
5. Septic tank is usually consists of brick wall in cement not less than _______
a) 20 cm
b) 100 cm
c) 80 cm
d) 200 cm
Explanation: Septic tank is usually consists of brick wall in cement not less than 20cm(9”) thick and the foundation floor are of cement concrete 1:3:6 or 1:2:4. Both inside and outside faces of wall and floor are plastered with a minimum thickness of 12mm thick cement mortar 1:3 and all inside corners are rounded
6. Connecting pipe should be _______ mm minimum diameter.
a) 60
b) 300
c) 700
d) 100
Explanation: It may be of R.C.C, Hume pipe, cast iron pipe, S.W. Inlet and outlet may be made through T-junction pipe or baffle wall of precast R.C.C. may be provided at a distance 1/5 of length of the septic tank so that the inlet sewage may not disturb the working of the tank.
7. Soak pit shall not be less than ____________
a) 45 cm
b) 90 cm
c) 50 cm
d) 100 cm
Explanation: Soak pit shall not be less than 90 cm in diameter and not less than 1.5 m in depth below invert level of the inlet pipe. The pit is constructed with lining of dry brick or stone with open joints backed with at least 7.5 cm thick coarse aggregate.
8. A _________ is a type of toilet that collects human faeces in a hole in the ground.
a) gutter
b) septic tank
c) pit toilet
d) latrine
Explanation: A pit latrine or pit toilet is a type of toilet that collects human faeces in a hole in the ground. They use either no water or one to three litres per flush with pour-flush pit latrines. When properly built and maintained they can decrease the spread of disease by reducing the amount of human faeces in the environment from open defecation. This decreases the transfer of pathogens between faeces and food by flies.
9. The pit is typically at least ____________ deep and ___________ across.
a) 14 meters, 10 m
b) 30 meters, 15 m
c) 3 meters, 1 m
d) 11 meters, 9 m
Explanation: The World Health Organization recommends they be built a reasonable distance from the house balancing issues of easy access versus that of smell. The distance from groundwater and surface water should be as large as possible to decrease the risk of groundwater pollution. The hole in the slab should not be larger than 25 cm (9.8 inches) to prevent children falling in. Light should be prevented from entering the pit to reduce access by flies. This may require the use of a lid to cover the hole in the floor when not in use.
10. The size of the faeces drop hole in the floor or slab should not be larger than ____________
a) 5m
b) 25 cm
c) 45 cm
d) 250 mm
Explanation: The user positions themself over the small drop hole during use. The size of the feces drop hole in the floor or slab should not be larger than 25 centimeters (9.8 inches) to prevent children falling in. Light should be prevented from entering the pit to reduce access by flies. This requires the use of a lid to cover the hole in the floor when not in use. However, in practice, such a lid is not commonly used as it is easy to lose it or for the lid to get very filthy.