Test: Environmental Engineering- 1 - Civil Engineering (CE) MCQ

TCU represent the true colour unit. It is a unit to represent colour impurities in water. 1 TCU is equivalent to the colour produced by 1 mg/L of platinum in form of chloroplatinate ion.

As per IS10500:2012, the total concentration of manganese (as Mn) and iron (as Fe) for drinking water purpose shall not exceed 0.3 mg/L.

1) Measurement suspended solid is done by a gravimetric test involving the mass of residual measurement.

2) Measurement of Turbidity: -

A) Based on absorption principles

i) Turbidity Rod

ii) Jackson’s Turbidity meter

iii) Baylis Turbidimeter

B) Based on the scattering principle

i) Modern Nephelometer

3) Through Nessler’s tubes on Burgess scale, true colour is measured.

Concept:-

pH = -log₁₀ [H⁺]

-log₁₀ [H⁺] = pH

[H⁺] = 10 ^-pH

Calculation

[H⁺]_I = 10^-6.2

[H⁺]_II = 10^-6.8

Hence, first sample is 4 times acidic than second sample.

Free Ammonia – indicate recent pollution

Nitrate – indicate old pollution (fully oxidized)

Nitrite – indicate partly decomposed condition

Organic – indicate quantity of nitrogen before decomposition started.

Concept:

Carbonate hardness = minimum of {Alkalinity, Total Hardness}

Total hardness = Carbonate Hardness + Non-carbonate Hardness.

Calculation:

Carbonate Hardness= minimum of {200 mg/L , 250 mg/L}

Carbonate Hardness = 200 mg/L as CaCO3

Non-Carbonate Hardness = Total Hardness – Carbonate Hardness

= 250 – 200

= 50 mg/L ​as CaCO₃

Concept:

Calculating fire Demand:

a) Kuchling’s formula

Q = 3182 √p

Where, Q = Amount of water required in liter/minute.

P = Population in Thousand

b) Freeman’s formula: -

Where, Q = Amount of water required in liter/minute.

P = Population in Thousand

c) National Bard of fire under writer formula:-

i. For central congested High valued city

→ when population ≤ 2 lakhs

Q = 4637 √ p [1 – 0.01 √p]

Where, Q = Amount of water required in liter/minute.

P = Population in Thousand

→ when population > 2 lakhs.

Provision of 54000 liters/minute may be made with an extra additional provision of 9100 to 36000 liter/minute for a second fire.

ii) for residential Buildings

→ Small or low building = 2200 l/min

→ Larger or higher building = 4500 l/min

→ High valued residency = (7650 – 13500) l/min

→ Three story building

 In densely built up area = up to 27000 l/min

d) Buston’s Formula: -

Q = 5663√ p

Calculation: -

According to Kuchling’s formula the fire demand is

Q = 3182 √P

Q = 3182 √150 L/min

Q = 38971.38 L/min

Q = 56.12 MLD ~ 57 MLD

Hardness (expressed as Ca CO 3 equivalent) is 75-115 ppm or mg/lit