PEC EPE Exam Environmental Engineering MCQ and Numerical Questions
Other PEC EPE Exam Past Paper Questions
What is the main purpose of a wastewater treatment plant?
a) Produce drinking water
b) Treat industrial wastewater
c) Remove pollutants from sewage
d) Generate electricity
Answer: c
Which of the following is a primary air pollutant?
a) Ozone (O3)
b) Carbon monoxide (CO)
c) Sulfur dioxide (SO2)
d) Particulate matter (PM10)
Answer: b
The BOD5 (Biochemical Oxygen Demand) test measures:
a) The amount of oxygen required by microorganisms to break down organic matter in water over 1 day
b) The concentration of nutrients in water bodies
c) The pH of water
d) The level of dissolved oxygen in water
Answer: a
Which process in a wastewater treatment plant involves the removal of suspended solids through gravitational settling?
a) Filtration
b) Aeration
c) Coagulation
d) Sedimentation
Answer: d
The term “Eutrophication” refers to:
a) The process of water purification
b) The introduction of chemicals into water bodies
c) Excessive nutrient enrichment causing excessive plant and algal growth
d) The formation of ozone in the atmosphere
Answer: c
Which greenhouse gas is primarily responsible for global warming?
a) Methane (CH4)
b) Carbon monoxide (CO)
c) Nitrogen dioxide (NO2)
d) Hydrogen sulfide (H2S)
Answer: a
Which of the following is a renewable energy source?
a) Coal
b) Natural gas
c) Nuclear power
d) Solar power
Answer: d
The process of converting solid waste into usable energy or materials is called:
a) Recycling
b) Composting
c) Landfilling
d) Waste-to-energy
Answer: d
What is the main purpose of a septic tank in on-site wastewater treatment?
a) To disinfect wastewater
b) To remove suspended solids
c) To separate and digest solids from wastewater
d) To remove nutrients from wastewater
Answer: c
The pH scale measures the acidity or alkalinity of a substance on a scale of:
a) 0 to 7
b) 1 to 14
c) -7 to 7
d) 0 to 14
Answer: d
Calculate the dilution factor when 100 mL of a solution is mixed with 500 mL of water.
Solution:
Dilution Factor = Volume of Final Solution / Volume of Initial Solution
Dilution Factor = (100 mL + 500 mL) / 100 mL = 6
Calculate the population equivalent for a restaurant that serves 150 meals per day, given that the BOD5 per meal is 200 g.
Solution:
Population Equivalent (PE) = Number of Meals per Day × BOD5 per Meal
PE = 150 × 200 g = 30,000 g = 30 kg
Determine the volume of sludge produced from a wastewater treatment plant processing 800 m³ of influent with a sludge concentration of 2% solids.
Solution:
Sludge Volume = Influent Volume × Sludge Concentration
Sludge Volume = 800 m³ × 0.02 = 16 m³
Calculate the amount of coagulant (Alum, Al2(SO4)3) required to treat 500,000 L of water with a turbidity of 40 NTU, assuming a dosage of 20 mg/L.
Solution:
Chemical Dosage = Dosage Rate × Volume of Water
Chemical Dosage = 20 mg/L × 500,000 L = 10,000,000 mg = 10 kg
Calculate the hydraulic residence time of a circular tank with a volume of 1500 m³ and a flow rate of 200 m³/day.
Solution:
Residence Time = Tank Volume / Flow Rate
Residence Time = 1500 m³ / 200 m³/day = 7.5 days
Calculate the carbon footprint of a car that travels 5000 km, consuming 7 liters of gasoline per 100 km, and emits 2.3 kg of CO2 per liter of gasoline burned.
Solution:
Carbon Footprint = Total Distance × (Fuel Consumption / 100) × CO2 Emission Factor
Carbon Footprint = 5000 km × (7 L / 100 km) × 2.3 kg/L = 805 kg
Determine the air exchange rate in a room with a volume of 100 m³ and a ventilation rate of 200 m³/hour.
Solution:
Air Exchange Rate = Ventilation Rate / Room Volume
Air Exchange Rate = 200 m³/hour / 100 m³ = 2 times per hour
Calculate the water footprint of producing 1 kg of beef, considering that it requires 15,000 liters of water.
Solution:
Water Footprint = Water Consumption per Unit × Quantity Produced
Water Footprint = 15,000 L/kg × 1 kg = 15,000 L
Calculate the energy consumption of a household that uses a 1500 W electric heater for 4 hours per day for a month.
Solution:
Energy Consumption = Power × Time
Energy Consumption = 1500 W × 4 hours/day × 30 days = 180,000 Wh = 180 kWh
Calculate the decay rate constant (k) for a pollutant with an initial concentration of 100 mg/L and a concentration of 20 mg/L after 10 days.
Solution:
Decay Rate (k) = (ln(C₀ / C)) / t
Decay Rate (k) = (ln(100 mg/L / 20 mg/L)) / 10 days ≈ 0.159 day⁻¹