Chemical Environmental Engineering

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2.Identify the incorrect statement regarding boiler water treatment and feed water quality.

Cooling and freezing water eliminates all bacteria contained within it.As boiler steam pressure rises, the permissible silica concentration in feed water decreases.High-pressure boiler feed water must have zero dissolved oxygen content.Caustic embrittlement in boiler metal parts results from excessive caustic soda concentration in the feed water.Proper water treatment prevents corrosion and scale formation inside boilers.

3.Why is it beneficial to have a specific minimum level of fluorine in drinking water?

To prevent tooth decayTo reduce scale buildupTo avoid water-related illnessesTo inhibit corrosion

4.In biological oxidation ponds, aerobic bacteria help treat polluted water primarily by facilitating which process?

Coagulating and flocculating colloidal particlesConverting carbon-based compounds into carbon dioxideOxidizing ammonia from decomposed nitrogenous substancesPerforming all of the above processes

5.What is the typical threshold limit value (TLV) for mercury concentration in drinking water, expressed in parts per million (ppm)?

0.001 ppm0.1 ppm1 ppm5 ppm

6.What effect does the presence of iron and manganese have on water?

Decreases the amount of dissolved oxygenStains bathroom fittingsCauses temporary water hardnessNo noticeable impact

7.What is the effect of soluble organic matter in contaminated water?

Excessive growth of unwanted vegetationReduction in dissolved oxygen levelsIncreased risk of combustionPotential for explosive reactionsNone of the above

8.Which illness are employees in cement factories and limestone mining sites more susceptible to?

9.What term describes the ratio between the oxygen present and the oxygen needed to stabilize sewage?

10.Within the troposphere (the atmospheric layer where weather occurs), how is the temperature 't' in °C at an altitude 'h' meters above sea level calculated, given that the temperature at sea level is 15°C?

11.Among the following, which air pollutant is considered the most harmful to the environment?

12.The dust removal efficiency of a cyclone separator is primarily influenced by which of the following?

DiameterVelocity of incoming gasTotal heightAll of the above

13.What is the primary cause of hydrodynamic noise, which originates from the movement of liquid?

Vibrations in the piping systemFormation and collapse of vapor bubbles (cavitation)Separation of the boundary layerVariations in the flow rate of the liquid

14.The noise generated by cooling fans used in air-cooled heat exchangers or cooling towers is primarily due to the turbulence caused by the blades moving through the air. How can this noise be minimized by adjusting the fan design?

By using a slower fan with more bladesBy selecting a fan with a larger diameterBy combining both a larger diameter and more bladesBy neither increasing blade count nor diameter

15.Which of the following are the primary pollutants emitted by the iron and steel industry?

Carbon monoxide, carbon dioxide, and sulfur dioxideHydrogen sulfide, nitric oxide, and sulfur trioxideCarbon dioxide, hydrogen sulfide, and nitrogen dioxideSulfur trioxide, nitrogen dioxide, and carbon dioxide

16.What is the name of a shallow water body where sewage is held and undergoes biological treatment?

17.Which method is used to eliminate suspended solids from wastewater produced in the blast furnace gas cooling and cleaning process?

Aerated stabilization pondRadial settling tank (thickener) with coagulants such as lime and ferrous sulfateRetention basinsScreening process

19.What is the term for particles with a diameter exceeding 75 micrometers (1 micrometer = 10⁻⁶ mm)?

GritDustPowderSmoke

20.How is wastewater from coal washing, containing approximately 3% suspended solids like clay, slate, and stone, treated to remove solid particles?

Through chemical coagulation processUsing sedimentation tanks fitted with mechanical scrapersBy employing vacuum filtration methodsWith the help of clarifier unitsBy membrane filtration techniques

How to prepare with Chemical Environmental Engineering MCQs

Work through questions topic by topic, then revisit any you answered incorrectly.
Read explanations carefully—they often cover facts that repeat across PPSC, FPSC, and NTS papers.
Pair subject practice with past papers to see how Chemical Environmental Engineering appears in real exam conditions.

Chemical Environmental Engineering

About this subject

Practice questions

1.Which substance is used to eliminate unpleasant smell and taste from water?

2.Identify the incorrect statement regarding boiler water treatment and feed water quality.

3.Why is it beneficial to have a specific minimum level of fluorine in drinking water?

4.In biological oxidation ponds, aerobic bacteria help treat polluted water primarily by facilitating which process?

5.What is the typical threshold limit value (TLV) for mercury concentration in drinking water, expressed in parts per million (ppm)?

6.What effect does the presence of iron and manganese have on water?

7.What is the effect of soluble organic matter in contaminated water?

8.Which illness are employees in cement factories and limestone mining sites more susceptible to?

9.What term describes the ratio between the oxygen present and the oxygen needed to stabilize sewage?

10.Within the troposphere (the atmospheric layer where weather occurs), how is the temperature 't' in °C at an altitude 'h' meters above sea level calculated, given that the temperature at sea level is 15°C?

11.Among the following, which air pollutant is considered the most harmful to the environment?

12.The dust removal efficiency of a cyclone separator is primarily influenced by which of the following?

13.What is the primary cause of hydrodynamic noise, which originates from the movement of liquid?

14.The noise generated by cooling fans used in air-cooled heat exchangers or cooling towers is primarily due to the turbulence caused by the blades moving through the air. How can this noise be minimized by adjusting the fan design?

15.Which of the following are the primary pollutants emitted by the iron and steel industry?

16.What is the name of a shallow water body where sewage is held and undergoes biological treatment?

17.Which method is used to eliminate suspended solids from wastewater produced in the blast furnace gas cooling and cleaning process?

18.Which disease is caused by breathing in silica dust?

19.What is the term for particles with a diameter exceeding 75 micrometers (1 micrometer = 10⁻⁶ mm)?

20.How is wastewater from coal washing, containing approximately 3% suspended solids like clay, slate, and stone, treated to remove solid particles?

How to prepare with Chemical Environmental Engineering MCQs

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