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GATE (CE) : SUBJECT REVISION QUIZ#7 (App update required to attempt this test)

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Question 1

Two primary air pollutants are

Question 2

Determine the critical deficit (in ppm) of dissolved oxygen when the stream flowing at a rate of 210 cumec with saturated dissolved oxygen limit of 10.6ppm is diluted with a sewage flowing at the rate of 1.35 cumec. Assume the Dissolved oxygen limit of waste water as 4ppm.

Question 3

500 kg BOD per day is applied to a high rate trickling filter having organic loading rate 1 kg/m3/day. Recirculation ratio is 1. Find the effluent BOD.

Question 4

Analysis of a water sample revealed that the sample contains the following species.

Concentrations of which of the species will be required to compute alkalinity?

Question 5

A water supply board is responsible for treating 1500 m3/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 tanks is ___________.

Question 6

A water sample has a pH of 8.32. The concentration of hydroxyl ions in the water sample is

Question 7

A settling tank in a water treatment plant is designed for a surface overflow rate of 30Description: D:\GradeStack Courses\GATE Tests (Sent by Ravi)\Civil-Engineering-2013_files\image146.png. Assume specific gravity of sediment particles = 2.65, density of water (r) = 1000 kg/m3, dynamic viscosity of water (m) = 0.001 N.s/m2, and Stokes’ law is valid. The approximate minimum size of particles that would be completely removed is:

Question 8

For a wastewater sample, the three-day biochemical oxygen demand at incubation temperature of 20 °C (BOD3day, 20 °C) is estimated as 200 mg/L. Taking the value of the first order BOD reaction rate constant as 0.22 day-1, the five-day BOD (expressed in mg/L) of the wastewater at incubation temperature of 20 °C (BOD5day, 20 °c) would be ___________

Question 9

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 ___________

Question 10

The concentration of Sulfur Dioxide (SO2) in ambient atmosphere was measured as 30 µg/m3. Under the same conditions, the above SO2 concentration expressed in ppm is ___________.
Given: (P/(RT) = 41.6 mol/m3; where, P = Pressure; T = Temperature; R – universal gas constant; Molecular weight of SO2 = 64.

Question 11

Two electrostatic precipitators (ESPs) are in series. The fractional efficiencies of the upstream and downstream ESPs for size dp are 80% and 65% respectively. What is the overall efficiency of the system for the same dp?

Question 12

A circular primary clarifier processes 5005 cubic meters of municipal wastewater every day. The overflow rate is 35m3/m2d. The diameter of the clarifier shall be _____.

Question 13

The sewage is flowing at 4.5 million litres per day from a primary clarifier to a standard rate trickling filter. BOD of influent is 180 mg/l, organic loading can be taken as 150 g/m3/day and surface loading as 2500 l/m2/day. The depth of filter is _______m.

Question 14

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

Question 15

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 °C and the temperature of the stream C is 10 °C. It is given that
∙ The 5-day BOD of the stream A measured at 20 °C=50 mg/l
∙ BOD rate constant (base 10) at 20 °C=0.115 per day
∙ Temperature coefficient = 1.135
The 5-day BOD (in mg/l, up to one decimal place) of the stream C, calculated at 10 °C, is ___________
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Jun 22ESE & GATE CE