GATE 2019 National Champion Test - Environmental Engineering for ESE & GATE CE Exams

Question 1

Which method is used to measure the color of water ?

Question 2

The maximum BOD (in mg/l) present in a solution of glucose of concentration 330 mg/l.

Question 3

The presence of fats and oils in the waste water are determined with the help of

Question 4

Assertion : Chemical oxygen demand of a sample is always greater than biochemical oxygen demand
Reason : Chemical oxygen demand represents biodegradable organic and inorganic matter whereas biochemical oxygen demand represents only biodegradable organic matter

Question 5

From the sample drawn from the aeration tank liquor of activated sludge process , a settling test was carried out with 1 litre of sample. Test yielded settled volume of 300 ml. MLSS = 3000 mg/l. Find the sludge volume index

Question 6

List 1 contains quality parameters of water and List 2 contains reagents required for computation. Choose the correct option.
List 1
P. Bacterial concentration
Q. COD
R. Dissolved Oxygen
S. Chlorine
List 2
1) Silver Nitrate
2) Lactose Broth
3) Sodium Thiosulphate
4) Alkali Iodide Azide

Question 7

An Ice-cream factory has a daily discharge of the waste water at the average rate of 2400 m³/day. The waste water coming out of the factory was tested at 2% dilution and following results were obtained:
* DO of aerated water = 5mg/l
* DO of diluted sample after 5 days = 1.4 mg/l
* Deoxygenation constant = 0.1 day^-1
Calculate the BOD₅ equivalent population

Question 8

An average operating data for conventional activated sludge treatment plant is as follows:
Influent BOD (So) = 200 mg/l
Effluent BOD(S) = 25 mg/l
MLSS(X) =3000 mg/l
Effluent suspended solids (Xe) = 40 mg/l
Waste sludge suspended solids (Xr) = 12000 mg/l
Wastewater flow (Q) = 50000 m³/day
Quantity of waste sludge (Qw) = 250 m³/day
Aeration period = 0.31 days
Find the sludge age in days

Question 9

A high rate trickling filter is used for treating wastewater of a town having population of 40000 persons.
Domestic sewage = 150 lpcd having 200 mg/l of BOD
Industrial sewage = 0.25 mlD having 600 mg/l of BOD
BOD removal in primary Clarifier = 35%
Permissible BOD loading = 8000 kg/hec m/day( including recirculated sewage)
Take recirculation ratio = 1
Use formula for efficiency = (100)/(1 + 0.44(√(W/V*F)))
V is volume, F is recirculation factor and W is BOD applied to filter
Find the efficiency of filter

Question 10

A high rate trickling filter is used for treating wastewater of a town having population of 40000 persons.
Domestic sewage = 150 lpcd having 200 mg/l of BOD
Industrial sewage = 0.25 mlD having 600 mg/l of BOD
BOD removal in primary Clarifier = 35%
Permissible BOD loading = 8000 kg/hec m/day( including recirculated sewage)
Take recirculation ratio = 1
Use formula for efficiency = (100)/(1 + 0.44(√(W/V*F)))
V is volume, F is recirculation factor and W is BOD applied to filter
Find the strength of effluent (mg/l)