# ENVIRONMENTAL ENGINEERING MCQs 16 | Civil Engineering Competitive Exams

#### ByCivilelite

Aug 2, 2022

1. A water treatment plant, having discharge 1 m^3/sec, has 14 filters to treat the water. Each filter is having 50m^2 area, but due to backwashing activity 2 filters are nonoperational. Calculate hydraulic loading rate in m^3/day m^2?

[A] 214
[B] 304
[C] 416
[D] 144

Explanation:

Hydraulic loading rate = Q/A =1/(12 * 50) m³/ (sec(m²))

= 1x 24 x 60 x 60 12x 50 m³/daym² =144m³ / daym²

2. Total Kjeldahl nitrogen is a measure of _____.

[A] total organic nitrogen
[B] total ammonia nitrogen
[C] total inorganic and ammonia nitrogen
[D] total organic and ammonia nitrogen

3. The reference pressure used in the determination of sound pressure level is _____.

[A] 10 uPa
[B] 10 dB
[C] 20uPa
[D] 20 dB

4. Zero hardness is achieved by _____.

[A] Excess alum dosage
[B]Excess lime treatment
[C] Lime-soda process
[D] lon exchange treatment

5. A sewer is commonly designed to attain self-cleansing velocity at _____.

[A] Minimum hourly rate of flow
[B] Peak hourly rate of flow
[C] Average hourly rate of flow
[D] Sewer running half full

Explanation:

Self-cleansing velocity is also the minimum velocity at which no solid gets deposited at the bottom of sewer. It must be developed at least once a day and a sewer is commonly designed to attain the self-cleansing velocity at minimum hourly rate of flow.