Recent questions in Water and Waste Water Quality and Treatment / GO Civil

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41

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:$...

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42

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...

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43

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

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44

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...

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45

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...

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46

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...

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47

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.$...

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48

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...

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49

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...

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50

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 ...

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51

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

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52

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...

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53

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...

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54

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...

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55

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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56

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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57

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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58

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...

gatecse

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59

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