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

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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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2

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

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Don6 asked May 11, 2021

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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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4

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

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Arjun asked Feb 19, 2021

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GATE Civil 2021 Set 1 | Question: 12
Which one of the following is correct? The partially treated effluent from a food processing industry, containing high concentration of biodegradable organics, is being discharged into a flowing river at a point $\text{P}$. If the rate of ... $1$ A young lake characterized by low nutrient content and low plant productivity is called $\textit{eutrophic lake}$

Which one of the following is correct?The partially treated effluent from a food processing industry, containing high concentration of biodegradable organics, is being di...

Arjun

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Arjun asked Feb 19, 2021

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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&...

Arjun

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Arjun asked Feb 19, 2021

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GATE Civil 2021 Set 1 | Question: 52
A secondary clarifier handles a total flow of $9600 \text{ m}^3\text{/d}$ from the aeration tank of a conventional activated-sludge treatment system. The concentration of solids in the flow from the aeration tank is $3000\text{ mg/L}$. ... . The surface area of the designed clarifier for thickening (in $\text{m}^2$, $\textit{in integer}$) is ___________________

A secondary clarifier handles a total flow of $9600 \text{ m}^3\text{/d}$ from the aeration tank of a conventional activated-sludge treatment system. The concentration of...

Arjun

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Arjun asked Feb 19, 2021

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8

GATE Civil 2021 Set 1 | Question: 34
Ammonia nitrogen is present in a given wastewater sample as the ammonium ion $\text({NH}_{4}$^{+})$ and ammonia $\text({NH}_{3})$. If $ ... _{3}$ will be found in equal measures At $\text{pH}$ $7.0$, $\text{NH}_{4}$^{+}$ will be predominant

Ammonia nitrogen is present in a given wastewater sample as the ammonium ion $\text({NH}_{4}$$^{+})$ and ammonia $\text({NH}_{3})$. If $\text{pH}$ is the only deciding fa...

Arjun

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Arjun asked Feb 19, 2021

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9

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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10

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...

go_editor

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go_editor asked Feb 27, 2020

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11

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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12

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...

go_editor

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go_editor asked Feb 13, 2020

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13

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}, ...

go_editor

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go_editor asked Feb 13, 2020

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14

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 $e$) (...

gatecse

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gatecse asked Aug 7, 2019

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15

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...

gatecse

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gatecse asked Aug 7, 2019

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16

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...