Most viewed questions in Environmental Engineering / GO Civil

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GATE2017 CE-1: 55
The wastewater having an organic concentration of $54$ mg/l is flowing at a steady rate of $0.8 \: m^3/day$ through a detention tank of dimensions $2m \times 4 m \times 2 m$. If the contents of the tank are well mixed and the decay constant $0.1$ per day, the outlet concentration (in mg/l, up to one decimal place) is _________

The wastewater having an organic concentration of $54$ mg/l is flowing at a steady rate of $0.8 \: m^3/day$ through a detention tank of dimensions $2m \times 4 m \times 2...

Milicevic3306

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Milicevic3306 asked Mar 26, 2018

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2

GATE2017 CE-2-8
As per Noise Pollution (Regulation and Control) Rules $2000$ of India, the day time noise limit for a residential zone, expressed in dB(A)L$_{eq}$, is $55$ $65$ $75$ $85$

As per Noise Pollution (Regulation and Control) Rules $2000$ of India, the day time noise limit for a residential zone, expressed in dB(A)L$_{eq}$, is$55$$65$$75$$85$

gatecse

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gatecse asked Aug 7, 2019

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3

GATE2018 CE-2: 51
At a small water treatment plant which has $4$ filters, the rates of filteration and backwashing are $200 \: m^3/d/m^2$ and $1000 m^3/d/m^2$, respectively. Backwashing is done for $15$ min per day. The maturation, which ... the water being wasted during backwashing and maturation. The percentage increase in the filtered water produced (up to two decimal places) would be ______

At a small water treatment plant which has $4$ filters, the rates of filteration and backwashing are $200 \: m^3/d/m^2$ and $1000 m^3/d/m^2$, respectively. Backwashing is...

gatecse

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gatecse asked Feb 17, 2018

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4

GATE2020-CE-1-25
A river has a flow of $1000$ million litres per day (MLD), $BOD_5$ of $5\:mg/litre$ and Dissolved Oxygen (DO) level of $8\:mg/litre$ before receiving the wastewater discharge at a location. For the existing environmental conditions, the saturation ... complete mixing of wastewater and river water, the immediate DO deficit (in $mg/litre$ round off to two decimal places), is ______.

A river has a flow of $1000$ million litres per day (MLD), $BOD_5$ of $5\:mg/litre$ and Dissolved Oxygen (DO) level of $8\:mg/litre$ before receiving the wastewater disch...

go_editor

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go_editor asked Feb 27, 2020

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5

GATE Civil 2012 | Question: 51
An activated sludge system (sketched below) is operating at equilibrium with the following information. Wastewater related data: flow rate $=500 \: m^3/hour$, influent BOD $= 150 mg/L$, effluent BOD $=10 \: mg/L$ ... $24000$ $1000$ $800$ $33$

An activated sludge system (sketched below) is operating at equilibrium with the following information. Wastewater related data: flow rate $=500 \: m^3/hour$, influent BO...

Milicevic3306

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Milicevic3306 asked Mar 25, 2018

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6

GATE2014-2-49
A waste water stream (flow $=2 m^3/s$, ultimate BOD$=90$ mg/l) is joining a small river (flow $=12 \: m^3/s$, ultimate BOD $=5$ mg/l). Both water streams get mixed up instantaneously. Cross-sectional area of the river is $50 \: m^2$. Assuming the de-oxygenation rate ... $10$ km downstream of the mixing point is $1.68$ $12.63$ $15.46$ $1.37$

A waste water stream (flow $=2 m^3/s$, ultimate BOD$=90$ mg/l) is joining a small river (flow $=12 \: m^3/s$, ultimate BOD $=5$ mg/l). Both water streams get mixed up ins...

Milicevic3306

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Milicevic3306 asked Mar 25, 2018

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7

GATE2016-2-18
A water supply board is responsible for treating $1500 \:m^3/day$ of water. A settling column analysis indicates that an overflow rate of $20 \: m/day$ will produce satisfactory removal for a depth of $3.1 \: m$. It is decided to have two circular settling tanks in parallel. The required diameter (expressed in $m$) of the settling tank is __________

A water supply board is responsible for treating $1500 \:m^3/day$ of water. A settling column analysis indicates that an overflow rate of $20 \: m/day$ will produce satis...

Milicevic3306

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Milicevic3306 asked Mar 27, 2018

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8

GATE2017 CE-2-9
Following observations have ben made for the elevation and temperature to ascertain the stability of the atmosphere: $\begin{array}{|c|c|} \hline \text{Elevation (in m) } & \text{Temperature (in }^{\circ} \text{C)} \\ \hline 10 & 15.5 \\ \hline 60 & 15.0 \\ \hline 130 & 14.3 \\ \hline \end{array}$ The atmosphere is classified as Stable Unstable Neutral Inverse

Following observations have ben made for the elevation and temperature to ascertain the stability of the atmosphere:$$\begin{array}{|c|c|} \hline \text{Elevation (in m) }...

gatecse

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gatecse asked Aug 7, 2019

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9

GATE2015-1-20
Total Kjeldahl Nitrogen (TKN) concentration (mg/L as N) in domestic sewage is the sum of the concentrations of organic and inorganic nitrogen in sewage organic nitrogen and nitrate in sewage organic nitrogen and ammonia in sewage ammnia and nitrate in sewage

Total Kjeldahl Nitrogen (TKN) concentration (mg/L as N) in domestic sewage is the sum of the concentrations oforganic and inorganic nitrogen in sewageorganic nitrogen and...

Milicevic3306

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Milicevic3306 asked Mar 26, 2018

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10

GATE2018 CE-2: 15
In the figures, Group I represents the atmospheric temperature profiles (P, Q, R and S) and Group II represents dispersion of pollutants from a smoke stack $(1, 2, 3$ and $4)$. In the figures of Group I, the dashed line represents the dry adiabatic lapse rate, whereas the horizontal axis represents temperature and ... $P-1, Q-4, R-3, S-2$ $P-3, Q-1, R-2, S-4$

In the figures, Group I represents the atmospheric temperature profiles (P, Q, R and S) and Group II represents dispersion of pollutants from a smoke stack $(1, 2, 3$ and...

gatecse

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gatecse asked Feb 17, 2018

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11

GATE2016-2-19
The hardness of a ground water sample was found to be $420 \: mg/L$ as $CaCO_3$. A softener containing ion exchange resins was installed to reduce the total hardness to $75 \: mg/L$ as $CaCO_3$ before supplying to $4$ households. Each household gets treated water at ... $100\%$, the bypass flow rate (expressed in $L/day$) is _________

The hardness of a ground water sample was found to be $420 \: mg/L$ as $CaCO_3$. A softener containing ion exchange resins was installed to reduce the total hardness to $...

Milicevic3306

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Milicevic3306 asked Mar 27, 2018

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12

GATE2020 CE-2-16
The relationship between oxygen consumption and equivalent biodegradable organic removal (i.e.,BOD) in a closed container with respect to time is shown in the figure Assume that the rate of oxygen consumption is directly proportional to the amount of degradable organic matter and is expressed as ... is $BOD_5 = L_5$ $BOD_t = L_0-L_t$ $L_0 = L_te^{-kt}$ $L_t = L_0(1-e^{-kt})$

The relationship between oxygen consumption and equivalent biodegradable organic removal (i.e.,BOD) in a closed container with respect to time is shown in the figureAssum...

go_editor

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go_editor asked Feb 13, 2020

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13

GATE Civil 2021 Set 2 | Question: 17
Which of the following statement$\text{(s)}$ is/are correct? Increased levels of carbon monoxide in the indoor environment result in the formation of carboxyhemoglobin and the long term exposure becomes a cause of cardiovascular diseases ... in the indoor environment will result in the formation of photochemical smog which is a cause of cardiovascular diseases

Which of the following statement$\text{(s)}$ is/are correct?Increased levels of carbon monoxide in the indoor environment result in the formation of carboxyhemoglobin and...

go_editor

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go_editor asked Mar 1, 2021

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14

Made Easy Gate Previous year Questions
If we have 3 samples Initial DO. Final DO. Volume 1. 9.2 6.9 5 2. 9.1 4.4 10 3. 8.4 0 50 Do we need to consider last sample for finding average BOD?

If we have 3 samples Initial DO. Final DO. Volume1. 9.2 6.9 52. 9.1 4.4 ...

Don6

130 points

Don6 asked May 11, 2021

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15

GATE2018 CE-2: 14
As per $\text{IS }10500:2012$, for drinking water in the absence of alternate source of water, the permissible limits for chloride and sulphate, in mg/L, respectively are $250$ and 200$ $1000$ and 400$ $200$ and 250$ $500$ and 1000$

As per $\text{IS }10500:2012$, for drinking water in the absence of alternate source of water, the permissible limits for chloride and sulphate, in mg/L, respectively are...

gatecse

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gatecse asked Feb 17, 2018

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16

GATE Civil 2021 Set 2 | Question: 51
An activated sludge process $\text{(ASP)}$ is designed for secondary treatment of $7500\:m^{3}/$day of municipal wastewater. After primary clarifier, the ultimate $\text{BOD}$ of the influent, which enters into $\text{ASP}$ ... underflow volume (in $m^{3}$/day, $\textit{round off to one decimal place}$) of sludge wastage is _______________________

An activated sludge process $\text{(ASP)}$ is designed for secondary treatment of $7500\:m^{3}/$day of municipal wastewater. After primary clarifier, the ultimate $\text{...

go_editor

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go_editor asked Mar 1, 2021

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17

GATE2018 CE-1: 33
A rapid sand filter comprising a number of filter beds is required to produce $99$ MLD of potable water. Consider water loss during backwashing as $5\%$, rate of filtration as 6.0 m/h and length to width ratio of filter bed as $1.35$. The width of each ... to take care of break-down, repair, and maintenance. The total number of filter beds required will be $19$ $20$ $21$ $22$

A rapid sand filter comprising a number of filter beds is required to produce $99$ MLD of potable water. Consider water loss during backwashing as $5\%$, rate of filtrati...

gatecse

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gatecse asked Feb 17, 2018

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18

GATE2019 CE-2: 41
Raw municipal solid waste (MSW) collected from a city contains $70 \%$ decomposable material that can be converted to methane. The water content of the decomposable material is $35\%$. An elemental analysis of the decomposable material yields the following mass percent. ... The mass of methane produced (in grams, round off to $1$ decimal place) per kg of raw MSW will be _________

Raw municipal solid waste (MSW) collected from a city contains $70 \%$ decomposable material that can be converted to methane. The water content of the decomposable mater...

Arjun

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Arjun asked Feb 12, 2019

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19

GATE2017 CE-1: 14
The wastewater from a city, containing a high concentration of biodegradable organics, is being steadily discharged into a flowing river at a location S. If the rate of aeration of the river water is lower than the rate of degradation of the organics, then the ... the location S. remains constant all along the length of the river. is lowest at a point downstream of the location S.

The wastewater from a city, containing a high concentration of biodegradable organics, is being steadily discharged into a flowing river at a location S. If the rate of a...

Milicevic3306

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Milicevic3306 asked Mar 26, 2018

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20

GATE2016-1-19
It was decided to construct a fabric filter, using bags of $0.45$ m diameter and $7.5$ m long, for removing industrial stack gas containing particulates. The expected rate of airflow into the filter is $10 \: m^3/s$. If the filtering velocity is $2.0$ m/min, the minimum number of bags (rounded to nearest higher integer) required for continuous cleaning operation is $27$ $29$ $31$ $32$

It was decided to construct a fabric filter, using bags of $0.45$ m diameter and $7.5$ m long, for removing industrial stack gas containing particulates. The expected rat...

Milicevic3306

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Milicevic3306 asked Mar 27, 2018

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21

GATE2014-2-21
The dominating microorganisms in an activated sludge process reactor are aerobic heterotrophs anaerobic heterotrophs autotrophs phototrophs

The dominating microorganisms in an activated sludge process reactor areaerobic heterotrophsanaerobic heterotrophsautotrophsphototrophs

Milicevic3306

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Milicevic3306 asked Mar 25, 2018

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22

GATE2019 CE-2: 42
Consider the reactor shown in the figure. The flow rate through the reactor is $Q \: m^3/h$. The concentrations (in $mg/L$) of a compound in the influent and effluent are $C_0$ and $C$, respectively. The compound is degraded in the reactor following the first order ... $L_{\text{CMFR}}/L_{\text{PFR}}$ (round off to $2$ decimal places) is ____________

Consider the reactor shown in the figure. The flow rate through the reactor is $Q \: m^3/h$. The concentrations (in $mg/L$) of a compound in the influent and effluent are...

Arjun

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Arjun asked Feb 12, 2019

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23

GATE Civil 2021 Set 2 | Question: 15
The hardness of a water sample is measured directly by titration with $\text{0.01 M}$ solution of ethylenediamine tetraacetic acid $\text{(EDTA)}$ using eriochrome black $\text{T (EBT)}$ as an indicator. The $\text{EBT}$ reacts ... colour of the solution changes from blue-green to reddish brown blue to colourless reddish brown to pinkish yellow Wine red to blue

The hardness of a water sample is measured directly by titration with $\text{0.01 M}$ solution of ethylenediamine tetraacetic acid $\text{(EDTA)}$ using eriochrome black ...

go_editor

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go_editor asked Mar 1, 2021

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24

GATE2017 CE-2-50
The composition of a municipal solid waste sample is given below: ... The difference between the energy content of the waste sample calculated on dry basis and as-discarded basis (in kJ/kg) would be _______

The composition of a municipal solid waste sample is given below:$\begin{array}{|l|c|c|c|} \hline \text{Component} & \text{Percent by} & \text{Moisture Content} & \text{E...

gatecse

4.0k points

gatecse asked Aug 7, 2019

1 votes

0 answers

25

GATE2015-2-50
In a wastewater treatment plant, primary sedimentation tank (PST) designed at an overflow rate of $32.5 \: m^3/day/m^2$ is $32.5$ m long, $8.0$ m wide and liquid depth of $2.25$ m. If the length of the weir is $75$ m, the weir loading rate (in $m^3/day/m$) is ______.

In a wastewater treatment plant, primary sedimentation tank (PST) designed at an overflow rate of $32.5 \: m^3/day/m^2$ is $32.5$ m long, $8.0$ m wide and liquid depth of...

Milicevic3306

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Milicevic3306 asked Mar 26, 2018

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26

GATE2019 CE-2: 40
A water treatment plant treats $6000 \: m^3$ of water per day. As a part of the treatment process, discrete particles are required to be settled in a clarifier. A column test indicates that an overflow rate of $1.5 \: m$ per hour would produce the desired removal of ... of $3.0 \:m$. The volume of the required clarifier, (in $m^3$, round off to $1$ decimal place) would be ______

A water treatment plant treats $6000 \: m^3$ of water per day. As a part of the treatment process, discrete particles are required to be settled in a clarifier. A column ...

Arjun

13.0k points

Arjun asked Feb 12, 2019

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27

GATE2019 CE-2: 32
Chlorine is used as the disinfectant in a municipal water treatment plant. It achieves $50$ percent of disinfection efficiency measured in terms of killing the indicator microorganisms (E-Coli) in $3$ minutes. The minimum time required to achieve $99$ percent disinfection efficiency would be $9.93$ minutes $11.93$ minutes $19.93$ minutes $21.93$ minutes

Chlorine is used as the disinfectant in a municipal water treatment plant. It achieves $50$ percent of disinfection efficiency measured in terms of killing the indicator ...

Arjun

13.0k points

Arjun asked Feb 12, 2019

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28

GATE2018 CE-1: 52
The ultimate BOD $(L_0)$ of a wastewater sample is estimated as $87 \%$ of COD. The COD of this wastewater is $300$ mg/L. Considering first order BOD reaction rate constant $k$ (use natural log) $= 0.23$ ... value in (in mg/L, up to one decimal place) after three days of incubation at $27^{\circ}$C for this wastewater will be _____

The ultimate BOD $(L_0)$ of a wastewater sample is estimated as $87 \%$ of COD. The COD of this wastewater is $300$ mg/L. Considering first order BOD reaction rate consta...

gatecse

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gatecse asked Feb 17, 2018

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29

GATE Civil 2021 Set 2 | Question: 52
A grit chamber of rectangular cross-section is to be designed to remove particles with diameter of $\text{0.25 mm}$ and specific gravity of $2.70$. The terminal settling velocity of the particles is estimated as $\text{2.5 cm/s}$. The ... the chamber (in $\text{m}, \textit{in integer}$) to remove $\text{0.25 mm}$ particles completely is ____________________

A grit chamber of rectangular cross-section is to be designed to remove particles with diameter of $\text{0.25 mm}$ and specific gravity of $2.70$. The terminal settling ...

go_editor

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go_editor asked Mar 1, 2021

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30

GATE2014-2-47
A surface water treatment plant operates round the clock with a flow rate of $35 \: m^3/min$. The water temperature is $15^{\circ}C$ and jar testing indicated an alum dosage of $25$ mg/l with flocculation at a $Gt$ value of $4 \times 10^4$ producing optimal results. The alum quantity required for $30$ days (in kg) of operation of the plant is _______

A surface water treatment plant operates round the clock with a flow rate of $35 \: m^3/min$. The water temperature is $15^{\circ}C$ and jar testing indicated an alum dos...

Milicevic3306

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Milicevic3306 asked Mar 25, 2018

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31

GATE2015-2-47
A landfill is to be designed to serve a population of $200000$ for a period of $25$ years. The solid waste (SW) generation is $2$ kg/person/day. The density of the un-compacted SW is $100 \: kg/m^3$ and a compaction ratio of $4$ is suggested. The ratio of compacted fill (i.e., SW+cover) to compacted SW is $1.5$. The landfill volume (in $million \: m^3$) required is _________.

A landfill is to be designed to serve a population of $200000$ for a period of $25$ years. The solid waste (SW) generation is $2$ kg/person/day. The density of the un-com...

Milicevic3306

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Milicevic3306 asked Mar 26, 2018

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32

GATE2014-1-21
Some of the nontoxic metals normally found in natural water are arsenic lead and mercury calcium sodium and silver cadmium, chromium and copper iron, manganese and magnesium

Some of the nontoxic metals normally found in natural water arearsenic lead and mercurycalcium sodium and silvercadmium, chromium and copperiron, manganese and magnesium

Milicevic3306

11.9k points

Milicevic3306 asked Mar 25, 2018

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1 answer

33

GATE2018 CE-1: 53
A waste activated sludge (WAS) is to be blended with green waste (GW). The carbon (C) and nitrogen (N) contents, per kg of WAS and GW, on dry basis are given in the table. ... $C: N$ ratio of $20:1$ on dey basis is ____

A waste activated sludge (WAS) is to be blended with green waste (GW). The carbon (C) and nitrogen (N) contents, per kg of WAS and GW, on dry basis are given in the table...

gatecse

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gatecse asked Feb 17, 2018

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34

GATE2016-1-51
An electrostatic precipitator (ESP) with $5600\:m^2$ of collector plate area is $96$ percent efficient in treating $185\:m^3/s$ of flue gas from a $200$ MW thermal power plant. It was found that in order to achieve $97$ percent efficiency, the collector plate ... $99$ percent, the ESP collector plate area (expressed in $m^2$) would be ______

An electrostatic precipitator (ESP) with $5600\:m^2$ of collector plate area is $96$ percent efficient in treating $185\:m^3/s$ of flue gas from a $200$ MW thermal power ...

Milicevic3306

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Milicevic3306 asked Mar 27, 2018

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35

GATE2014-1-46
$16$ MLD of water is flowing through a $2.5$ km long pipe of diameter $45$ cm. The chlorine at the rate of $32$ kg/d is applied at the entry of this pipe so that disinfected water is obtained at the exit. There is a proposal to increase the flow through this ... per day) to be applied to achieve the same degree of disinfection for the enhanced flow is $60.50$ $44.00$ $38.00$ $23.27$

$16$ MLD of water is flowing through a $2.5$ km long pipe of diameter $45$ cm. The chlorine at the rate of $32$ kg/d is applied at the entry of this pipe so that disinfec...

Milicevic3306

11.9k points

Milicevic3306 asked Mar 25, 2018

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1 answer

36

GATE2018 CE-1: 25
A city generates $40 \times 10^6$ kg of municipal solid waste (MSW) per year, out of which only $10\%$ is recovered/recycled and the rest goes to landfill. The landfill has a single life of $3$ m height and is compacted to a density of $550 \: kg/m^3$. If $80 \%$ of the landfill is assumed to be MSW, the landfill area (in $m^2$, up to one decimal place) required would be _______

A city generates $40 \times 10^6$ kg of municipal solid waste (MSW) per year, out of which only $10\%$ is recovered/recycled and the rest goes to landfill. The landfill h...

gatecse

4.0k points

gatecse asked Feb 17, 2018

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37

GATE Civil 2021 Set 1 | Question: 28
A $50$ $\text{mL}$ sample of industrial wastewater is taken into a silica crucible. The empty weight of the crucible is $54.352$ $\text{g}$. The crucible with the sample is dried in a hot air oven at $104\;^{\circ}C$ till a constant weight of ... volatile solids is _____________________ $\text{15540 mg/L}$ $\text{8620 mg/L}$ $\text{6920 mg/L}$ $\text{1700 mg/L}$

A $50$ $\text{mL}$ sample of industrial wastewater is taken into a silica crucible. The empty weight of the crucible is $54.352$ $\text{g}$. The crucible with the sample ...

Arjun

13.0k points

Arjun asked Feb 19, 2021

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38

GATE2014-2-48
An effluent at a flow rate of $2670 \: m^3/d$ from a sewage treatment plant is to be disinfected. The laboratory data of disinfection studies with a chlorine dosage of $15$ mg/l yield the model $N_t=N_oe^{-0.145t}$ where $N_t=$ number of micro-organisms surviving ... (at $t=0$). The volume of disinfection unit (in $m^3$) required to achieve a $98\%$ kill micro-organisms is __________

An effluent at a flow rate of $2670 \: m^3/d$ from a sewage treatment plant is to be disinfected. The laboratory data of disinfection studies with a chlorine dosage of $1...

Milicevic3306

11.9k points

Milicevic3306 asked Mar 25, 2018

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39

GATE2017 CE-2-52
A municipal corporation is required to treat $1000 \: m^3/day$ of water. It is found that an overflow rate of $20 m/day$ will produce a satisfactory removal of the discrete suspended particles at a depth of $3 m$. The diameter (in meters, round to the nearest integer) of a circular settling tank designed for the removal of these particles would be ___________

A municipal corporation is required to treat $1000 \: m^3/day$ of water. It is found that an overflow rate of $20 m/day$ will produce a satisfactory removal of the discre...

gatecse

4.0k points

gatecse asked Aug 7, 2019

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40

GATE Civil 2021 Set 1 | Question: 51
A baghouse filter has to treat $12\text{ m}^3/\text{s}$ of waste gas continuously. The baghouse is to be divided into $5$ ... $5 \text{ m}$ in length. The total number of bags ($\textit{in integer}$) required in the baghouse is __________________

A baghouse filter has to treat $12\text{ m}^3/\text{s}$ of waste gas continuously. The baghouse is to be divided into $5$ sections of equal cloth area such that one secti...

Arjun

13.0k points

Arjun asked Feb 19, 2021