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Civil EngineeringWBPSC AE · SSC JE · RRB JE

Environmental Engineering— Important Topics, Formulas & MCQs

Environmental Engineering covers water supply, wastewater treatment, air and solid-waste management. It is largely conceptual with standard process sequences and quality parameters — high-yield and not too calculation-heavy.

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Important topics in Environmental Engineering

Water demand & quality standards
Water treatment — coagulation, sedimentation, filtration, disinfection
Hardness & its removal
Sewage characteristics — BOD, COD
Wastewater treatment — primary, secondary, tertiary
Trickling filters & activated sludge
Sludge digestion (Imhoff tank)
Air pollution & control
Solid waste management
Disinfection & chlorination
Must-know

Key concepts & formulas — Environmental Engineering

Treatment sequence

Screening → grit removal → primary sedimentation → coagulation/flocculation → secondary sedimentation → filtration → disinfection.

Zero hardness

Achieved by ion-exchange (zeolite/resin) — lime-soda leaves residual hardness.

Primary vs secondary pollutant

Primary emitted directly (NO, SO₂, CO, soot); secondary formed in the atmosphere (O₃, PAN).

Imhoff tank

Combines sedimentation and sludge digestion in a single two-storey unit.

Exam relevance

6–8 questions in AE/JE papers; conceptual marks that are quick to secure.

Study tip

Memorise the treatment-process order and unit functions — most MCQs test sequence and purpose.

Worked example

Sample Environmental Engineering MCQ

Zero hardness of water is best achieved by:

A. Lime-soda process
B. Boiling
C. Ion-exchange (zeolite) process
D. Aeration
Answer: C. The ion-exchange (zeolite/resin) process can reduce hardness to nearly zero; the lime-soda process leaves about 40 ppm residual hardness.

Common mistakes to avoid

Treatment order: screening → grit removal → primary sedimentation → coagulation/flocculation → secondary sedimentation → filtration → disinfection.
Primary pollutants are emitted directly (NO, SO₂, CO); secondary ones form in the atmosphere (O₃, PAN).
An Imhoff tank combines sedimentation and sludge digestion in one unit.
COD is always greater than BOD for the same wastewater.
Keep going

Related Civil Engineering subjects

Strength of Materials
RCC
Steel Structures
Soil Mechanics
Foundation Engineering
Surveying
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