Recent questions in Environmental Engineering / GO Civil

0 votes

0 answers

41

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

11.9k points

Milicevic3306 asked Mar 27, 2018

0 votes

0 answers

42

GATE2016-2-20
The sound pressure (expressed in $\mu P a$) of the faintest sound that a normal healthy individual can hear is $0.2$ $2$ $20$ $55$

The sound pressure (expressed in $\mu P a$) of the faintest sound that a normal healthy individual can hear is$0.2$$2$$20$$55$

Milicevic3306

11.9k points

Milicevic3306 asked Mar 27, 2018

0 votes

0 answers

43

GATE2016-2-50
A sample of water has been analyzed for common ions and results are presented in the form of a bar diagram as shown. The non-carbonate hardness (expressed in mg/L as $CaCO_3$) of the sample is $40$ $165$ $195$ $205$

A sample of water has been analyzed for common ions and results are presented in the form of a bar diagram as shown.The non-carbonate hardness (expressed in mg/L as $CaCO...

Milicevic3306

11.9k points

Milicevic3306 asked Mar 27, 2018

0 votes

0 answers

44

GATE2016-2-51
A noise meter located at a distance of $30 \: m$ from a point source recorded $74 \: dB$. The reading at a distance of $60 \: m$ from the point source would be __________

A noise meter located at a distance of $30 \: m$ from a point source recorded $74 \: dB$. The reading at a distance of $60 \: m$ from the point source would be __________...

Milicevic3306

11.9k points

Milicevic3306 asked Mar 27, 2018

0 votes

0 answers

45

GATE2016-2-52
For a wastewater sample, the three-day biochemical oxygen demand at incubation temperature of $20^{\circ}C$ (BOD$_{\text{3day}, 20^{\circ}C}$) is estimated as $200 mg/L$ ... in mg/L) of the wastewater at incubation temperature of $20^{\circ}C$ (BOD$_{\text{5day}, 20^{\circ}C}$) would be ________

For a wastewater sample, the three-day biochemical oxygen demand at incubation temperature of $20^{\circ}C$ (BOD$_{\text{3day}, 20^{\circ}C}$) is estimated as $200 mg/L$....

Milicevic3306

11.9k points

Milicevic3306 asked Mar 27, 2018

0 votes

0 answers

46

GATE2016-1-17
Pre-cursors to photochemical oxidants are $NO_X, \: VOC$s and sunlight $SO_2, \: CO_2$ and sunlight $H_2S, \: CO$ and sunlight $SO_2, \: NH_3$ and sunlight

Pre-cursors to photochemical oxidants are$NO_X, \: VOC$s and sunlight$SO_2, \: CO_2$ and sunlight$H_2S, \: CO$ and sunlight$SO_2, \: NH_3$ and sunlight

Milicevic3306

11.9k points

Milicevic3306 asked Mar 27, 2018

0 votes

0 answers

47

GATE2016-1-18
Crown corrosion in a reinforced concrete sewer is caused by: $H_2S$ $CO_2$ $CH_4$ $NH_3$

Crown corrosion in a reinforced concrete sewer is caused by:$H_2S$$CO_2$$CH_4$$NH_3$

Milicevic3306

11.9k points

Milicevic3306 asked Mar 27, 2018

0 votes

0 answers

48

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

11.9k points

Milicevic3306 asked Mar 27, 2018

0 votes

0 answers

49

GATE2016-1-20
Match the items in Group - I with those in Group - II and choose the right combination. ... $P - 1; \: Q - 4; \: R - 2; \: S - 3$

Match the items in Group – I with those in Group – II and choose the right combination.$$\begin{array}{llll} {} & \underline{\text{Group – I}} & {} & \underline{\...

Milicevic3306

11.9k points

Milicevic3306 asked Mar 27, 2018

0 votes

0 answers

50

GATE2016-1-50
Effluent from an industry ‘A’ has a pH of $4.2$. The effluent from another industry ‘B’ has double the hydroxyl (OH) ion concentration than the effluent from industry ‘A’. pH of effluent from the industry ‘B’ will be ______

Effluent from an industry ‘A’ has a pH of $4.2$. The effluent from another industry ‘B’ has double the hydroxyl (OH) ion concentration than the effluent from indu...

Milicevic3306

11.9k points

Milicevic3306 asked Mar 27, 2018

0 votes

0 answers

51

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

11.9k points

Milicevic3306 asked Mar 27, 2018

0 votes

0 answers

52

GATE2016-1-52
The $2$-day and $4$-day BOD values of a sewage sample are $100$ mg/L and $155$ mg/L, respectively. The value of BOD rate constant (expressed in per day) is __________

The $2$-day and $4$-day BOD values of a sewage sample are $100$ mg/L and $155$ mg/L, respectively. The value of BOD rate constant (expressed in per day) is __________

Milicevic3306

11.9k points

Milicevic3306 asked Mar 27, 2018

0 votes

0 answers

53

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

11.9k points

Milicevic3306 asked Mar 26, 2018

0 votes

0 answers

54

GATE2017 CE-1: 52
The equivalent sound power level (in dB) of the four sources with the noise levels of $60$ dB, $69$ dB, $70$ dB and $79$ dB is ______

The equivalent sound power level (in dB) of the four sources with the noise levels of $60$ dB, $69$ dB, $70$ dB and $79$ dB is ______

Milicevic3306

11.9k points

Milicevic3306 asked Mar 26, 2018

0 votes

0 answers

55

GATE2017 CE-1: 54
Two wastewater streams A and B, having an identical ultimate BOD are getting mixed to form the stream C. The temperature of the stream A is $20^{\circ}C$ and the temperature of the stream C is $10^{\circ}C$. It is given that the $5$-day BOD of the stream A measured ... The $5-$day BOD (in mg\I, up to one decimal place ) of the stream C, calculated at $10^{\circ} C$, is _________

Two wastewater streams A and B, having an identical ultimate BOD are getting mixed to form the stream C. The temperature of the stream A is $20^{\circ}C$ and the temperat...

Milicevic3306

11.9k points

Milicevic3306 asked Mar 26, 2018

1 votes

1 answer

56

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

11.9k points

Milicevic3306 asked Mar 26, 2018

0 votes

0 answers

57

GATE2015-2-21
$SO_2$ and $CO$ adversely affect oxygen carrying capacity of blood and functioning of lungs respectively functioning of the respiratory system and brain respectively functioning of the respiratory system and oxygen carrying capacity of blood respectively functioning of air passages and chest respectively

$SO_2$ and $CO$ adversely affectoxygen carrying capacity of blood and functioning of lungs respectivelyfunctioning of the respiratory system and brain respectivelyfunctio...

Milicevic3306

11.9k points

Milicevic3306 asked Mar 26, 2018

0 votes

0 answers

58

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

11.9k points

Milicevic3306 asked Mar 26, 2018

0 votes

0 answers

59

GATE2015-2-48
A water treatment plant of capacity, $1 \: m^3/s$ has filter boxed of dimensions $6 \; m \times 10 \: m$. Loading rate to the filters is $120 \: m^3/day/m^2$. When two of the filters are out of service for back washing, the loading rate (in $m^3/day/m^2$) is _________.

A water treatment plant of capacity, $1 \: m^3/s$ has filter boxed of dimensions $6 \; m \times 10 \: m$. Loading rate to the filters is $120 \: m^3/day/m^2$. When two of...

Milicevic3306

11.9k points

Milicevic3306 asked Mar 26, 2018

0 votes

0 answers

60

GATE2015-2-49
Ultimate BOD of a river water sample is $20$ mg/L. BOD rate constant (natural log) is $0.15 \: day^{-1}$. The respective values of BOD (in $\%$) exerted and remaining after $7$ days are: $45$ and $55$ $55$ and $45$ $65$ and $35$ $75$ and $25$

Ultimate BOD of a river water sample is $20$ mg/L. BOD rate constant (natural log) is $0.15 \: day^{-1}$. The respective values of BOD (in $\%$) exerted and remaining aft...

Milicevic3306

11.9k points

Milicevic3306 asked Mar 26, 2018

1 votes

0 answers

61

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

11.9k points

Milicevic3306 asked Mar 26, 2018

0 votes

0 answers

62

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

11.9k points

Milicevic3306 asked Mar 26, 2018

0 votes

0 answers

63

GATE2015-1-21
Solid waste generated from an industry contains only two components, X and Y as shown in the table below. ... $100(c_1 \rho_1 +c_2 \rho_2) \\$ $100 \bigg( \dfrac{\rho_1 \rho_2}{c_1 \rho_1 + c_2 \rho_2} \bigg)$

Solid waste generated from an industry contains only two components, X and Y as shown in the table below.$$\begin{array}{ccc} \textbf{Component} & \textbf{Composition} & ...

Milicevic3306

11.9k points

Milicevic3306 asked Mar 26, 2018

0 votes

0 answers

64

GATE2015-1-49
The concentration of Sulfur Dioxide $(SO_2)$ in ambient atmosphere was measured as $30 \: \mu g /m^3$. Under the same conditions, the above $SO_2$ concentration expressed in ppm is _________. Given: $P/(RT) = 41.6 \: mol/m^3$; where, $P=$ Pressure; $T=$ Temperature; $R=$ universal gas constant; Molecular weight of $SO_2 =64$.

The concentration of Sulfur Dioxide $(SO_2)$ in ambient atmosphere was measured as $30 \: \mu g /m^3$. Under the same conditions, the above $SO_2$ concentration expressed...

Milicevic3306

11.9k points

Milicevic3306 asked Mar 26, 2018

0 votes

0 answers

65

GATE2015-1-50
Consider a primary sedimentation tank (PST) in a water treatment plant with Surface Overflow Rate (SOR) of $40\:m^3/m^2/d$. The diameter of the spherical particle which will have $90$ percent theoretical removal efficiency in this tank is ______ $\mu m$. Assume that settling velocity of the ... $g=9.81 \: m/s^2$; Kinematic viscosity of water $(v) = 1.10 \times 10^{-6} m^2/s$.

Consider a primary sedimentation tank (PST) in a water treatment plant with Surface Overflow Rate (SOR) of $40\:m^3/m^2/d$. The diameter of the spherical particle which w...

Milicevic3306

11.9k points

Milicevic3306 asked Mar 26, 2018

0 votes

0 answers

66

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

11.9k points

Milicevic3306 asked Mar 25, 2018

0 votes

0 answers

67

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

0 votes

0 answers

68

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

11.9k points

Milicevic3306 asked Mar 25, 2018

0 votes

0 answers

69

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

11.9k points

Milicevic3306 asked Mar 25, 2018

0 votes

0 answers

70

GATE2014-2-22
The two air pollution control devices that are usually used to remove very fine particles from the flue gas are Cyclone and Venturi Scrubber Cyclone and Packed Scrubber Electrostatic Precipitator and Fabric Filter Settling Chamber and Tray Scrubber

The two air pollution control devices that are usually used to remove very fine particles from the flue gas areCyclone and Venturi ScrubberCyclone and Packed ScrubberElec...

Milicevic3306

11.9k points

Milicevic3306 asked Mar 25, 2018

0 votes

0 answers

71

GATE2014-1-48
For a sample water with the ionic composition shown in the figure below, the carbonate and non-carbonate hardness concentrations (in mg/l as $CaCO_3$), respectively are: $200$ and $50$ $175$ and $75$ $75$ and $175$ $50$ and $200$

For a sample water with the ionic composition shown in the figure below, the carbonate and non-carbonate hardness concentrations (in mg/l as $CaCO_3$), respectively are:$...

Milicevic3306

11.9k points

Milicevic3306 asked Mar 25, 2018

0 votes

0 answers

72

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

0 votes

0 answers

73

GATE2014-1-22
The amount of $CO_2$ generated (in kg) while completely oxidizing one kg of $CH_4$ to the end products is _________

The amount of $CO_2$ generated (in kg) while completely oxidizing one kg of $CH_4$ to the end products is _________

Milicevic3306

11.9k points

Milicevic3306 asked Mar 25, 2018

0 votes

0 answers

74

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

0 votes

0 answers

75

GATE Civil 2013 | Question: 43
A student began experiment for determination of $5$-day, $20^{\circ}C$ BOD on Monday. Since the $5$th day fell on Saturday, the final DO readings were taken on next Monday. On calculation, BOD (i.e. $7$ day, $20^{\circ}C$ was found to be $150$ ... )? Assume value of BOD rate constant $(k)$ at standard temperature of $20^{\circ}C$ as $0.23/day$ (base $e$). ___________

A student began experiment for determination of $5$-day, $20^{\circ}C$ BOD on Monday. Since the $5$th day fell on Saturday, the final DO readings were taken on next Monda...

Milicevic3306

11.9k points

Milicevic3306 asked Mar 25, 2018

0 votes

0 answers

76

GATE Civil 2013 | Question: 42
A settling tank in a water treatment plant is designed for a surface overflow rate of $30 \dfrac{m^3}{\text{day} \cdot m^2}$. Assume specific gravity of sediment particles $=2.65$, density of water $(\rho) =1000 \: kg/m^3$, dynamic viscosity of ... The approximate minimum size of particles that would be completely removed is $0.01$ mm $0.02$ mm $0.03$ mm $0.04$ mm

A settling tank in a water treatment plant is designed for a surface overflow rate of $30 \dfrac{m^3}{\text{day} \cdot m^2}$. Assume specific gravity of sediment particle...

Milicevic3306

11.9k points

Milicevic3306 asked Mar 25, 2018

0 votes

0 answers

77

GATE Civil 2013 | Question: 21
A water treatment plant is designed to treat $1 \: m^3/s$ of raw water. It has $14$ sand filters. Surface area of each filter is $50 \: m^2$. What is the loading rate (in $\dfrac{m^3}{\text{day} \cdot m^2}$) with two filters out of service for routine backwashing? __________

A water treatment plant is designed to treat $1 \: m^3/s$ of raw water. It has $14$ sand filters. Surface area of each filter is $50 \: m^2$. What is the loading rate (in...

Milicevic3306

11.9k points

Milicevic3306 asked Mar 25, 2018

0 votes

0 answers

78

GATE Civil 2013 | Question: 20
Some of the water quality parameters are measured by titrating a water sample with a titrant. Group I gives a list of parameters and Group-II gives the list of titrants. ... $P - 2, Q - 1, R - 4, S - 3$ $P - 4, Q - 3, R - 2, S - 1$

Some of the water quality parameters are measured by titrating a water sample with a titrant. Group I gives a list of parameters and Group-II gives the list of titrants.$...

Milicevic3306

11.9k points

Milicevic3306 asked Mar 25, 2018

0 votes

0 answers

79

GATE Civil 2012 | Question: 50
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 $=10 \: mg/L$. Aeration tank related data: hydraulic retention ... ratio (in kg BOD per kg biomass per day) for the aeration tank is $0.015$ $0.210$ $0.225$ $0.240$

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

Milicevic3306

11.9k points

Milicevic3306 asked Mar 25, 2018

0 votes

0 answers

80

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

11.9k points

Milicevic3306 asked Mar 25, 2018