Recent activity in Water and Waste Water Quality and Treatment

0 votes

0 answers

1

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{...

110 points

ishita29 answered Feb 3, 2023

0 votes

0 answers

2

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...

100 points

Chandanachandu recategorized May 30, 2021

0 votes

0 answers

3

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

100 points

Chandanachandu recategorized May 30, 2021

0 votes

0 answers

4

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:$...

100 points

Chandanachandu edited May 29, 2021

0 votes

0 answers

5

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

100 points

Chandanachandu edited May 29, 2021

0 votes

0 answers

6

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...

100 points

Chandanachandu retagged May 29, 2021

0 votes

0 answers

7

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...

100 points

Chandanachandu retagged May 29, 2021

0 votes

0 answers

8

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...

100 points

Chandanachandu edited May 29, 2021

0 votes

0 answers

9

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.$...

100 points

Chandanachandu recategorized May 29, 2021

0 votes

0 answers

10

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...

100 points

Chandanachandu retagged May 29, 2021

0 votes

0 answers

11

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...

100 points

Chandanachandu recategorized May 29, 2021

0 votes

0 answers

12

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...

100 points

Chandanachandu retagged May 29, 2021

0 votes

0 answers

13

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...

100 points

Chandanachandu edited May 29, 2021

0 votes

0 answers

14

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...

100 points

Chandanachandu edited May 29, 2021

0 votes

0 answers

15

GATE Civil 2012 | Question: 42
A water sample has a pH of $9.25$. The concentration of hydroxyl ions in the water sample is $10^{-9.25}$ moles/L $10^{-4.75}$ mmoles/L $0.302$ mg/L $3.020$ mg/L

A water sample has a pH of $9.25$. The concentration of hydroxyl ions in the water sample is$10^{-9.25}$ moles/L$10^{-4.75}$ mmoles/L$0.302$ mg/L$3.020$ mg/L

100 points

Chandanachandu recategorized May 29, 2021

0 votes

0 answers

16

GATE Civil 2012 | Question: 43
A town is required to treat $4.2 \: m^3/min$ of raw water for daily domestic supply. Flocculating particles are to be produced by chemical coagulation. A column analysis indicated that an overflow rate of $0.2$ mm/s will produce satisfactory particles removal in a ... depth of $3.5$ m. The required surface area (in $m^2$) for settling is $210$ $350$ $1728$ $21000$

A town is required to treat $4.2 \: m^3/min$ of raw water for daily domestic supply. Flocculating particles are to be produced by chemical coagulation. A column analysis ...

100 points

Chandanachandu edited May 29, 2021

0 votes

0 answers

17

GATE Civil 2012 | Question: 20
A sample of domestic sewage is digested with silver sulphate, sulphuric acid, potassium dichromate and mercuric sulphate in chemical oxygen demand (COD) test. The digested sample is then titrated with standard ferrous ammonium sulphate (FAS) to determine the un-reacted amount of mercuric sulphate potassium dichromate silver sulphate sulphuric acid

A sample of domestic sewage is digested with silver sulphate, sulphuric acid, potassium dichromate and mercuric sulphate in chemical oxygen demand (COD) test. The digeste...

100 points

Chandanachandu edited May 29, 2021

0 votes

0 answers

18

GATE Civil 2012 | Question: 21
... $\textbf{[a]}$ and $\textbf{[r]}$ are false $\textbf{[a]}$ is true but $\textbf{[r]}$ is false

$\begin{array}{lcl} \textbf{Assertion [a]} &: & \text{At a manhole, the crown of the outgoing sewer should not be higher} \\ & & \text{than the crown of the incoming sewe...

100 points

Chandanachandu retagged May 29, 2021

1 votes

0 answers

19

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...

100 points

Chandanachandu retagged May 28, 2021

0 votes

0 answers

20

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...

100 points

Chandanachandu edited May 28, 2021

0 votes

0 answers

21

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...

100 points

Chandanachandu retagged May 27, 2021

0 votes

0 answers

22

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...

100 points

Chandanachandu recategorized May 27, 2021

0 votes

0 answers

23

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 $...

100 points

Chandanachandu recategorized May 27, 2021

0 votes

0 answers

24

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...

100 points

Chandanachandu edited May 27, 2021

0 votes

0 answers

25

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 $200 mg/L$....

100 points

Chandanachandu retagged May 27, 2021

0 votes

0 answers

26

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{\...

100 points

Chandanachandu retagged May 27, 2021

0 votes

0 answers

27

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...

100 points

Chandanachandu retagged May 27, 2021

0 votes

0 answers

28

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 __________

100 points

Chandanachandu recategorized May 27, 2021

0 votes

0 answers

29

GATE2017 CE-2-51
For a given water sample, the ratio between BOD$_{\text{5-day, 20}^{\circ} C}$ and the ultimate BOD is $0.68$. The value of the reaction rate constant $k$ (on base $e$) (in day$^{-1}$, up to two decimal places) is ________

For a given water sample, the ratio between BOD$_{\text{5-day, 20}^{\circ} C}$ and the ultimate BOD is $0.68$. The value of the reaction rate constant $k$ (on base $e$) (...

100 points

Chandanachandu retagged May 25, 2021

0 votes

0 answers

30

GATE2017 CE-2-10
The most important type of species involved in the degradation of organic matter in the case of activated sludge process is autotrophs heterotrophs prototrophs photo-autotrophs

The most important type of species involved in the degradation of organic matter in the case of activated sludge process isautotrophsheterotrophsprototrophsphoto-autotrop...

100 points

Chandanachandu edited May 25, 2021

1 votes

1 answer

31

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...

100 points

Chandanachandu retagged May 25, 2021

0 votes

0 answers

32

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...

100 points

Chandanachandu recategorized May 25, 2021

0 votes

0 answers

33

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...

100 points

Chandanachandu edited May 25, 2021

0 votes

1 answer

34

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...

100 points

Chandanachandu recategorized May 23, 2021

0 votes

1 answer

35

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...

100 points

Chandanachandu retagged May 22, 2021

0 votes

1 answer

36

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...

100 points

Chandanachandu recategorized May 22, 2021

0 votes

1 answer

37

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...

100 points

Chandanachandu retagged May 22, 2021

0 votes

1 answer

38

GATE2018 CE-1: 51
A water sample analysis data is given below, ... $CaCO_3$, up to one decimal place), for the water sample, is ____

A water sample analysis data is given below,$$\begin{array}{|c|c|} \hline \textbf{Ion} & \textbf{Concentration, mg/L} & \textbf{Atomic Weight} \\ \hline Ca^{2+} & 60 & 40...

100 points

Chandanachandu retagged May 22, 2021

0 votes

1 answer

39

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...

100 points

Chandanachandu recategorized May 22, 2021

0 votes

0 answers

40

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...

100 points

Chandanachandu recategorized May 18, 2021

0 votes

0 answers

41

GATE2019 CE-1: 42
A wastewater is to be disinfected with $35 \: mg/L$ of chlorine to obtain $99 \%$ kill of micro-organisms. The number of micro-organisms remaining alive $(N_t)$ at time $t$, is modelled by $N_t=N_o e^{-kt}$, where $N_o$ is number of micro-microorganisms at $t=0$, ... $1.0 \: m$, respectively, the length of the tank (in $m$, round off to $2$ decimal places) is ________

A wastewater is to be disinfected with $35 \: mg/L$ of chlorine to obtain $99 \%$ kill of micro-organisms. The number of micro-organisms remaining alive $(N_t)$ at time $...

100 points

Chandanachandu retagged May 17, 2021

0 votes

0 answers

42

GATE2019 CE-1: 34
Sedimentation basin in a water treatment plant is designed for a flow rate of $0.2 \: m^3/s$. The basin is rectangular with a length of $32 \: m$, width of $8 \:m $, and depth of $4 \: m$. Assume that the settling velocity of these particles is governed by ... diameter $25 \mu m$ (spherical and uniform), the removal efficiency of these particles is $51 \%$ $65 \%$ $78 \%$ $100 \%$

Sedimentation basin in a water treatment plant is designed for a flow rate of $0.2 \: m^3/s$. The basin is rectangular with a length of $32 \: m$, width of $8 \:m $, and ...

100 points

Chandanachandu edited May 17, 2021

0 votes

0 answers

43

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...

100 points

Chandanachandu recategorized May 12, 2021

1 votes

0 answers

44

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 ...

130 points

Don6 asked May 11, 2021

0 votes

0 answers

45

GATE2020 CE-2-52
The ion product of water $(pK_w)$ is $14$. If a rain water sample has a $pH$ of $5.6$, the concentration of $OH^-$ in the sample (in $10^{-9}\: \text{mol/litre}$, round off to one decimal place), is ________.

The ion product of water $(pK_w)$ is $14$. If a rain water sample has a $pH$ of $5.6$, the concentration of $OH^-$ in the sample (in $10^{-9}\: \text{mol/litre}$, round o...

100 points

Chandanachandu recategorized May 10, 2021

0 votes

0 answers

46

GATE2020 CE-2-54
A sample of water contains an organic compound $C_8H_{16}O_8$ at a concentration of $10^{-3}\: \text{mol/litre}$. Given that the atomic weight of $C = 12\: \text{g/mol}, H = 1\: \text{g/mol}$, and $O = 16\: \text{g/mol}$, the theoretical oxygen demand of water (in $g$ of $O_2$ per litre, round off to two decimal places), is ________.

A sample of water contains an organic compound $C_8H_{16}O_8$ at a concentration of $10^{-3}\: \text{mol/litre}$. Given that the atomic weight of $C = 12\: \text{g/mol}, ...

100 points

Chandanachandu recategorized May 10, 2021

0 votes

0 answers

47

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...

100 points

Chandanachandu recategorized May 8, 2021

0 votes

0 answers

48

GATE2020-CE-1-54
A stream with a flow rate of $5\:m^3/s$ is having an ultimate BOD of $30\:mg/litre$. A wastewater discharge of $0.20\:m^3/s$ having $BOD_5\:\text{of}\:500\:mg/litre$ joins the stream at a location and instantaneously gets mixed up completely. The ... $e$). The BOD (in mg/litre, round off to two decimal places) remaining at $3\:km$ downstream from the mixing location, is __________

A stream with a flow rate of $5\:m^3/s$ is having an ultimate BOD of $30\:mg/litre$. A wastewater discharge of $0.20\:m^3/s$ having $BOD_5\:\text{of}\:500\:mg/litre$ join...

100 points

Chandanachandu retagged May 8, 2021

0 votes

0 answers

49

GATE Civil 2021 Set 1 | Question: 33
A water sample is analyzed for coliform organisms by the multiple-tube fermentation method. The results of confirmed test are as follows: $\begin{array}{|cl|cI|cI|}\hline &\textbf{Sample size $ ... $110$ The $\text{MPN}$ of coliform organisms per $\text{100 mL}$ is $1100000$ $110000$ $1100$ $110$

A water sample is analyzed for coliform organisms by the multiple-tube fermentation method. The results of confirmed test are as follows:$\begin{array}{|cl|cI|cI|}\hline&...

100 points

Chandanachandu retagged May 4, 2021

0 votes

0 answers

50

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 ...

100 points

Chandanachandu recategorized May 4, 2021

To see more, click for all the questions in this category.