Chapter 6 · MCQ Read Mode

Water Supply, Sanitation and Environment

Compared to surface water sources, groundwater sources generally offer:

Colloidal impurities in water are best described as:

Temporary (carbonate) hardness in water can be removed by:

A disease such as malaria, transmitted by insects that breed in or near water, is classified as a:

Water-washed diseases are primarily linked to:

Drinking water quality standards specify bacteriological parameters primarily by testing for:

Peak factors used in water demand estimation account for: adequately

Alkalinity in water is primarily attributed to the presence of:

Permanent (non-carbonate) hardness in water, unlike temporary hardness, requires removal by:

Water demand for a community's design typically includes all of the following EXCEPT:

An infiltration gallery, as a type of water intake, works by:

A key factor in selecting the location of a water intake is:

A check (non-return) valve in a water distribution system serves to:

A break pressure tank (BPT) is primarily installed to: segments

The primary functions of a service reservoir in a water supply system include:

A branch (dead-end/tree-type) water distribution system, compared to a looped system, generally has the disadvantage of:

A looped (grid) water distribution system offers the advantage of:

Flanged joints in water supply pipelines are typically used where:

An air valve in a water distribution pipeline functions to:

The capacity of a service reservoir is commonly estimated as approximately: demand-supply pattern

The primary purpose of screening as the first step in water treatment is to:

Coagulation is necessary in water treatment because: they can aggregate and settle

Flocculation, following coagulant dosing, involves: settleable flocs

A slow sand filter, compared to a rapid sand filter, is characterized by: but requiring large land area

Rapid sand filters are typically cleaned by:

Disinfection in water treatment is primarily intended to:

Softening of water, to remove hardness caused by calcium and magnesium, is commonly achieved by:

Removal of iron and manganese from water typically involves: resulting precipitates

Activated carbon is commonly used in water treatment to address:

Aeration in water treatment serves to:

The quantity of wastewater generated by a community is commonly estimated as:

A separate sewerage system, compared to a combined system, offers the advantage of: the treatment plant

A combined sewerage system carries the risk of:

A minimum (self-cleansing) velocity is specified in sewer design primarily to:

An egg-shaped sewer cross-section is particularly useful for:

A drop manhole is used in sewer construction to: pipe

An inverted siphon in a sewerage system is used where: pressure through that section

Vitrified clay pipes, as a sewer material, are notable for their:

Catch basins/inlets in a sewerage/drainage system primarily function to:

Ventilating shafts along a sewer line serve to:

Aerobic decomposition of organic matter in wastewater, compared to anaerobic decomposition, is characterized by: dioxide and water

BOD5, as a standard wastewater parameter, measures: at 20°C

COD is generally numerically higher than BOD for the same wastewater sample because: the biodegradable fraction

A grit chamber, as part of primary wastewater treatment, is designed to: in suspension for downstream treatment

The activated sludge process, as a secondary treatment method, involves: sludge returned to maintain the microbial population

Oxidation ponds, as a wastewater treatment method, are characterized by: land area and longer retention time

The oxygen sag curve describes: and reaeration processes interact

The Streeter-Phelps equation is used to model: on deoxygenation and reaeration rate constants

A septic tank, used for on-site wastewater sanitation, functions primarily as a: pit/field for effluent disposal

Sludge disposal processes commonly include, in sequence:

Among BES, IEE, and EIA, which represents the most comprehensive level of environmental assessment, required for large-scale or high-impact projects?

An IEE (Initial Environmental Examination) is typically applied to projects with:

The tiered BES/IEE/EIA system for environmental assessment exists primarily to:

In Nepal, the requirements for BES, IEE, and EIA, including which project categories need each, are governed by:

A landslide triggered by unregulated construction or deforestation would typically be classified as a:

Structural mitigation measures for disaster risk reduction include: stabilization works

Non-structural disaster mitigation measures include:

Effective disaster risk reduction generally requires:

A Brief Environmental Study (BES) is typically applied to:

The environmental assessment approval process in Nepal, under the governing Rules/Regulations, generally requires: implementation

Which of the following is a surface source of water?

Most common surface water source is .............

Which of the following source gives underground water?

Which of the following is not a subsurface source of water?

Infiltration wells are .............

Shallow horizontal tunnels constructed along the river on its bank to intercept groundwater are called .............

Which is the following factors considered for the selection of a particular source of water?

Which water has a less chance of contaminated by bacteria?

Water may not contain much impurities if its source is .............

Ground water is usually free from .............

The water which is not chemically pure but does not contain anything harmful to human being health is known as .............

The maximum permissible limit of turbidity in drinking water as per Nepal Standard is ............. NTU.

Department of water supply and sewerage (DWSS) was formally established in ............. AD.

The new National Drinking Water Quality Standard (NDWQS) came into effect in ............. AD.

Example of aquaclude is .............

Which aquifer is called water table aquifer?

Unconfined aquifer is known as .............

What is the upper surface of water in a confined aquifer called?

A geological formation, which not only stores water but yields it in sufficient quantity is known as .............

An aquifer confined at the bottom, and not at top is called ............. aquifer.

An artesian well is also known as ............. well.

The minimum quantity of water that can be supplied from spring during driest period is known as ............. yield.

Storage capacity of a reservoir depends on .............

A city supply does not include .............

Which of the following statement is correct?

Which is the correct statement regarding per capita demand?

Which of the following causes a decreases in per capita consumption?

Water lost in theft and waste contributes to how much % of total consumption?

The unit of per capita demand is .............

The per capita day demand of water is taken as an average value of over a period of .............

The domestic demand in rural areas of Nepal is ............. lpcd.

The livestock demand should not be more than ............. of domestic demand.

As per DWSS, fire demand in Nepal should not more than ............. lpcd.

As per DWSS guidelines, the fire demand in Nepal should not be more than ............. lpcd.

The reserve of water for breakdown period is generally not more than ............. of total storage.

According to Buston's formula, fire demand in liters per minute for a population of P thousands, is .............

In water supply, the industrial demand should be .............

............. Is the water that does not form lather directly with the soap.

When total hardness is more than alkalinity .............

Hardness of water is conventionally expressed in terms of equivalent amount of .............

Select the incorrect statement from the following option.

Select the incorrect statement from the following option.

Select the incorrect statement from the following option.

Which of the following is not a unit of hardness?

Temporary hardness in water is caused by ............. of Ca and Mg.

Alkalinity in water is expressed as milligrams per liter in terms of equivalent .............

If total hardness of water is greater than total alkalinity, the carbonate hardness will be equal to .............

When temporary hard water is boiled, one of the substances formed is .............

If total alkalinity of water sample is 100 mg/l and its total hardness is 300 mg/l, then its carbonate and non-carbonate hardness are respectively .............

The pH value of water indicates .............

Water borne disease are also known as .............

Malaria, yellow fever are example of .............

Worm and viruses are also known as ............. organism present water.

Which of the following is not a water borne disease?

Ascariasis is a ............. infection.

Psychrophilic bacteria survive in between the temperature of ............. degree Celsius.

An organism that survives at a moderate temperature range between 20 to 45°C is .............

The bacteria that more at high temperature 40° to 70° is called .............

E-coli and coliform are known as .............

Coliform bacteria present in the water is an indication of .............

Which of the following can be designated as an intake structure?

From high level water resource, the water supply system used in termed as .............

Which of the following intake structure is widely used in small work?

The placement of intake is not optimal when it is placed in?

Intake in water supply system should not be located .............

The type of water supply system generally used in hilly region is .............

As compared to HDPE pipes, GI pipes are .............

Which of the following is a disadvantage of Asbestos cement pipe?

The tensile strength of Asbestos cement pipes is .............

Which of the following is the advantage of cast iron pipes?

Which of the following is incorrect regarding cast iron pipes?

What is the quantity of lead required for a 15 cm diameter cast iron pipe?

Which grade of concrete is used in Reinforced concrete pipes?

Which of the following is correct regarding Cement concrete pipes?

The gate valves are made of ............. with brass mountings.

Which type of joint is commonly used in cement concrete pipes for water supply and drainage systems?

To connect two lengths of pipe previously set in place, you should use a pipe .............

In which of the following joint, pipes do not have sockets or spigots?

For cement concrete pipes with plain ends, the joint commonly used is .............

Which of the following joint is called run lead joint?

Which of the following joint is highly influenced by temperature?

The type of joints used in concrete pipes is .............

Which of the following is also known as a check valve?

Which of the following is known as washout valve?

Which of the following is known as Shut off valve?

Air relief valves are provided in water supply mains at .............

Float valve fitted in .............

Foot valve is at bottom of .............

This cock fitted before nylon connection of wash basin and flushing cistern .............

Cock used in wash basin is .............

The spacing between the Sluice valves is .............

This valve protect the pipe line from bursting due to excess pressure .............

Pressure relief valves may help in .............

Scour valves are provided .............

A scour valve, in a water distribution system, is provided at .............

The types of valves used in distribution system when two or more pipes joins at each other is .............

............. valves are used to discharge air from the water pipelines.

In distribution system, the drain valves is provided at .............

What type of fitting is used to connect pipe of different diameter?

The purpose of providing a balancing reservoir in a water supply distribution system is .............

The appropriate diameter of a water main for supplying 1800 cu.m/hour with velocity of 1 m/s is .............

The four major water supply distribution systems are .............

The layout of the distribution system in which the water flows towards the periphery is ............. system.

The suitable layout for a water supply distribution system, for a city of roads of rectangular pattern is .............

The suitable layout for a water supply distribution system for an irregularly grown town is .............

When in the completely opened position, which of the listed types of valve will offer the least resistance to flow?

Which method of population forecast combines both arithmetical increase and geometrical increase method?

The layout of water distribution system generally found in an old city is .............

The best system for distribution of water in a randomly planned city is .............

Which method is accurate for forecasting population for sound and rapidly increasing city?

Sewerage system is designed for .............

Grit particle is .............

The minimum size of grit particles that can be removed in grit chamber is .............

Which of the following is not generated in waste treatment processes?

Usually while designing what is the range of length of the aerated grit chamber assumed?

The process of passing the water through beds of granular material is known as .............

Which of the following processes are necessary for removing suspended solids from water?

What is the opening spacing of bars in case of coarse screen?

What is the typical size and spacing of a coarse screen inclined at 45° to 60°, generally used for filtration?

When impurities are separated by the gravitation of settling particles, the operation is called .............

For plain sedimentation tank, the detention period is usually ............. hours.

A sedimentation tank of 20 m × 5 m × 3 m receives a flow of 1200 cu.m/day continuously, the detention time will be ............. hours.

The time period for which the water is stored in a sedimentation tank is called .............

The ratio of discharge to plan area in continuous flow sedimentation tank is known as .............

What is the time period for which the water is stored in fill and draw type of sedimentation tank?

What is the maximum permissible velocity in horizontal flow type sedimentation tank?

The overflow rate of plain sedimentation tank is about ............. cu.m/day/ sq. m.

The tanks built with mechanical means for continuous removal of solids being deposited by sedimentation are called .............

In which type of settling, sedimentation of discrete particles takes place?

What is formed when coagulant is added to water?

The amount of coagulant needed for coagulation of water increases with .............

The most commonly used coagulant is .............

Why alum is preferred over other coagulants?

Alum acts as .............

The chemical composition of Alum is .............

The optimum dosage of alum is determined by .............

In a water treatment, the optimum time of flocculation is usually given as 30 minutes. In case the time of flocculation is increased beyond this value, the flocs will .............

Particle of around 1 micron is removed by .............

The effective size of the sand particles used in the top layer of slow sand filter is in the range of .............

During treatment of water, sedimentation is done .............

Which of the following is not commonly used as a filter material in the treatment of water?

The uniformity characteristics of sand expressed in terms of .............

The slow sand filter can remove bacteria as much as ............. %

Consider the following statements regarding sand as filter material. i. It should be free from clay or silt ii. Organic matter should be present in the sand iii. It should be uniform. Which of the above statement is/are correct?

The cleaning of slow sand filter is done by .............

The organic impurities are converted into simple and harmless compounds in filtration due to .............

In slow sand filters, the turbidity of raw water can be removed only up to .............

The rate of filtration in slow sand filter is of the order of ............. liters per hour per m².

In rapid sand filter, the rate of filtration ranges from .............

The hydraulic loading for a high rate trickling filter varies between ............. per hectare per day.

Which of the following is not used as a media for trickling filters?

The thickness of filter media of slow sand filter is .............

Zeolites can be regenerated by passing a solution of .............

Zeolite softening process removes .............

The chemical formula for zeolite is .............

The treatment of water with bleaching powder is known as .............

Sterilization of water helps in killing of .............

Disinfection of water helps in .............

Chlorination of water does not remove .............

The common methods used for disinfection in waste water treatment plants are .............

Infiltration, the amount of dissolved solid passing through the filters is .............

At the break point chlorination, the residual chlorine is .............

Break-point chlorination of water involves addition of chlorine in and amount sufficient to .............

Chlorine demand of water is equal to .............

The process in which chlorination is done beyond break point is known as .............

Chlorine usage in the treatment of 30000 cubic meter of water per day is 15 kg/day. The chlorine dose is .............

Which chemical is used for dechlorination of water?

Use of chlorine in water does not reduce .............

The chlorine, which serves as a disinfectant is .............

When adding a chlorine in a water it reduces the .............

The efficiency of disinfection by chlorine in water treatment, .............

The permissible limit of free residual chlorine is .............

Which of the following is not significantly affected by chlorination in water?

Which of the following statement is wrong regarding iron salt?

A method that is not used to remove iron and manganese from water is .............

Which chemical is not effective for removal of iron and manganese?

Aeration of water is done to remove .............

NTU is unit .............

Degree hazen is a unit of .............

Foul odor and bad taste of water is removed by treating with .............

In most cases, oxidation is best method suitable for .............

Activated carbon is used in water treatment for .............

Activated carbon removes from water .............

Which of the following is the most toxic metal found in water?

Which method is used to measure the color of water?

Storm water flow or run off is given by .............

Factor affecting sanitary sewage are .............

The value of coefficient of runoff for paved areas is of the order of .............

The water carried sewerage system removes .............

............. is required to transport storm water runoff from roofs, parking lots, streets, and highways to a point of discharge.

............. is additional flow through sewers available during rainy season?

Sanitary sewage is independent of .............

The type of wastewater that originates from the bathroom, kitchen, washing places and wash basins is called .............

The most suitable sewer in combined sewerage system is .............

In which kind of cities are combined systems used?

When only one set of sewers are used to carry both sanitary sewage and storm water, it is called as ............. system.

When rainy season is confined to a few months, like in Nepal, the preferred sewerage system would be .............

The suitable system for an area having uniformly distributed mild rains throughout the year, like in England is .............

Two sets of sewers are laid in ............. system.

The treatment is costly in which of the following systems?

Which of the following is an advantage of separate sewers?

Which one of the following options is true for combined system of sewerage system?

Sewerage system is usually designed for .............

What is the name of the sewer that collects water from a number of other large sewers or outlets?

Which one of the following options is true for combined system of sewerage system?

The egg shaped sewer is best preferred on .............

The sewer that carries sewage to a treatment plant or final disposal point is called .............

Inverted syphon sewer is also called .............

The sewer used to convey wastewater form one or more lateral sewer is .............

The equipment used for checking the levels of the sewer invert is .............

Laying of sewers is usually done with the help of .............

1/4 to 1/3 space is left vacant in the design of sewer pipes at maximum discharge due to .............

In a circular sewer of diameter D, if the depth of the flow is D/4, the wetted perimeter will be .............

The internal diameter of the sewer should not be less than .............

Minimum size of public sewer should not be less than .............

If sizes of the sewers are ............. choking problems are less.

An egg shaped sewer in comparison to circular sewer is .............

Which of the following test of the sewer is done by placing a mirror at one end?

Testing of sewer pipes may involve .............

Testing of sewer is done by which of the following methods .............

Why is air gap left at the top of sewers?

The minimum diameter of sewer pipe is .............

Sewers are designed for .............

The slope of a sewer will be .............

To design sewer pipes of diameters 0.4 m to 0.9 m at maximum flow, the flow in sewer is running at .............

The best sewer material to resist hydrogen sulphide corrosion is .............

A masonry or RCC chamber constructed at suitable intervals along the sewer lines, for providing access into them is called .............

The manhole covers are generally made circular .............

The means of access for inspection and cleaning of sewer line is known as .............

Manholes on sewer lines are provided for .............

A drop manhole is provided if .............

Manholes are generally located .............

The drop manholes are provided in sewerage system when there is .............

For very small sewers, the maximum manhole spacing, specified by Indian standards, is .............

What is the spacing of manholes for pipe diameter of greater than 2 m?

The minimum diameter of a manhole cover should be .............

For large sewers, the maximum distance between manholes should be .............

What are the manholes having a depth greater than 1.5 m called?

The manhole is termed as shallow manhole if its depth is about .............

The minimum depth of septic tank as per design consideration is .............

When two pipes are connected to a manhole, how should their levels be arranged?

What are the structures that are constructed at suitable intervals along the sewerage system called?

A pipe used to carry discharge from sanitary fittings like bathrooms, kitchens, etc. is called .............

The pipe through which liquid waste carrying human excreta flows, is called .............

The sewage which transports the sewage to the point of treatment, is called .............

Specific gravity of the sewage is generally .............

The approximate % of water in sewage is .............

The specific gravity of sewage is .............

In the process of finding fixed inorganic solid in a sludge sample, the temp is .............

The process of finding fixed organic solid in sludge temp is .............

The value of ratio of BOD/COD of domestic wastewater before treatment is .............

The ratio of COD to BOD of untreated sewage is .............

The standard BOD is taken as .............

The maximum efficiency of BOD removal is achieved in .............

A BOD removal efficiency of 95% can be expected from .............

Between BOD and COD, the greater will be .............

The BOD of drinking water should not be more than .............

The standard 5-days BOD at 20 degree Celsius, when compared to ultimate BOD, is about .............

The efficiency of biochemical oxygen demand (BOD) removal in trickling filter is .............

If 2% solution of a sewage sample is incubated for 5 days at 20°C and depletion of oxygen was found to be 5 ppm, BOD of the sewage is .............

Which of the following has minimum detention period?

Grit chambers of a sewage plant are usually cleaned after .............

For plain sedimentation tank, the detention period is usually .............

The overflow rate of plain sedimentation tank is about ............. cu.m/day/ sq. m.

If sewage contains greases and fatty oils, they are removed in .............

The discharge per unit plan area of a sedimentation tank, is generally called .............

The organic loading in a trickling filter is measured in .............

A trickling filter is primarily a .............

In trickling filter, what is the phenomenon of losing slime layer called .............

When a recirculation ratio in a high rate trickling filter is unity, then the recirculation factor is .............

Activated sludge is the .............

The dominating microorganisms in an activated sludge process reactor are .............

Chlorine is sometimes used in sewage treatment .............

In the activated sludge process .............

In the oxidation ditch, the excess sludge is taken to .............

In an oxidation pond, the sewage is treated by .............

From amongst the following sewage treatment option, largest land requirements for a given discharge will be needed for .............

The minimum design depth of oxidation pond is ............. m.

The detention period for oxidation ponds is usually kept as .............

Factor affecting self-purifications are .............

Sewage that has received no purification treatment is called .............

When wastewater is disposed off into a running stream, 4 zones are formed. In which of the following zones will the minimum level of dissolved oxygen be found?

If DO concentration falls down to zero in any natural drainage, it indicates the zone of .............

The DO level in natural unpolluted waters at normal temperature is found to be of the order of .............

DO test is done by .............

The minimum DO in water bodies should be ............. to have aquatic life possible or survive.

Winkler's method is used to determine .............

Anaerobic reaction depends upon .............

Anaerobic decomposition of sewage is carried out .............

Aerobic bacteria's .............

Identify the waste water treatment unit which use both aerobic and anaerobic mechanism for the removal of organic matter?

If a sewer drain carrying a discharge of 2 cumecs, outfalls into a river carrying a discharge of 10 cumecs, and having DO equal to 8.4 mg/l, the resultant DO of the mix will be equal to .............

The gas, which is evolved in a sludge digestion tank, is mainly composed of .............

The color of digested sludge is .............

Composting and lagooning are methods of .............

Leachate is the colored liquid, that comes out of .............

The method of refuse disposal, involving burial in trenches, is called .............

Imhoff cone is used to measure ............. in sewage.

The diameter of vent pipe used in VIP latrine is .............

Septic tank is provided for .............

The minimum depth of septic tank as per design criteria is .............

Out of the following sewage treatment units, which work on the anaerobic decomposition of organic matter .............