Environmental Engineering Civil Gate Previous Year Questions
Ques 1Gate 2022 Set-1
The total hardness in raw water is 500 milligram per liter as CaCO3. The total hardness of this raw water, expressed in milligram equivalent per liter, is
(Consider the atomic weights of Ca, C, and O as 40 g/mol, 12 g/mol, and 16 g/mol, respectively.)
a. 10
b. 100
c. 1
d. 5
a is the correct answer.
Ques 2Gate 2022 Set-1
For wastewater coming from a wood pulping industry, Chemical Oxygen Demand (COD) and 5-day Biochemical Oxygen Demand (BOD5) were determined. For this wastewater, which of the following statement(s) is/are correct?
a. COD > BOD5
b. COD ≠ BOD5
c. COD < BOD5
d. COD = BOD5
a,b is the correct answer.
Ques 3Gate 2022 Set-1
Which of the following process(es) can be used for conversion of salt water into fresh water?
a. Microfiltration
b. Electrodialysis
c. Ultrafiltration
d. Reverse osmosis
b,d is the correct answer.
Ques 4Gate 2021 Set-2
The hardness of a water sample is measured directly by titration with 0.01 M solution of ethylenediamin etetraacetic acid (EDTA) using eriochrome black T (EBT) as an indicator. The EBT reacts and forms complexes with divalent metallic cations present in the water. During titration, the EDTA replaces the EBT in the complex. When the replacement of EBT is complete at the end point of the titration, the colour of the solution changes from
a. blue to colourless
b. blue-green to reddish brown
c. wine red to blue
d. reddish brown to pinkish yellow
c is the correct answer.
Ques 5Gate 2021 Set-1
Which one of the following is correct?
a. 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 P. If the rate of degradation of the organics is higher than the rate of aeration, then dissolved oxygen of the river water will be lowest at point P.
b. For an effluent sample of a sewage treatment plant, the ratio o 5day20 C BOD upon ultimate BOD is more than 1.
c. A young lake characterized by low nutrient content and low plant productivity is called eutrophic lake.
d. The most important type of species involved in the degradation of organic matter in the case of activated sludge process basedwastewater treatment is chemoheterotrophs.
d is the correct answer.
Ques 6Gate 2020 Set-2
A gas contains two types of suspended particles having average sizes of 2 μm and50 μm. Amongst the options given below, the most suitable pollution control strategyfor removal of these particles is
a. electrostatic precipitator followed by cyclonic separator
b. bag filter followed by electrostatic precipitator
c. settling chamber followed by bag filter
d. electrostatic precipitator followed by venturi scrubber
c is the correct answer.
Ques 7Gate 2020 Set-1
An amount of 35.67 mg HCI is added to distilled water and the total solution volume is made to one litre. The atomic weights of H and CI are 1 and 35.5, respectively. Neglecting the dissociation of water, the pH of the solution, is
a. 2.01
b. 3.50
c. 3.01
d. 2.50
c is the correct answer.
Ques 8Gate 2019 Set-1
Which one of the following is a secondary pollutant?
a. Ozone
b. Carbon Monoxide
c. Volatile Organic Carbon (VOC)
d. Hydrocarbon
a is the correct answer.
Ques 9Gate 2018 Set-1
There are 20,000 vehicles operating in a city with an average annual travel of 12,000 km per vehicle. The NOx emission rate is 2.0 g/km per vehicle. The total annual release of NOx will be
a. 4,80,000 kg
b. 4,800 kg
c. 480 kg
d. 48 kg
a is the correct answer.
Ques 10Gate 2017 Set-1
The wastewater form 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 dissolved oxygen of the river water
a. is lowest at the locations S
b. is lowest at a point upstream of the location S.
c. remains constant all along the length of the river.
d. is lowest at a point downstream of the location S.
d is the correct answer.