B. Only very fresh sewage contains some dissolved oxygen

C. The solubility of oxygen in sewage is 95% that is in distilled water

D. In treated sewage, 4 ppm of D.O. is essential

A. Hydrogen

B. Ammonia

C. Carbon dioxide

A. The bottom is silted

B. The bottom is scoured

C. Both silting and scouring occur at the bottom

B. 3 minutes

C. 5 minutes

D. 2 minutes

A. Branch sewer

C. House sewer

D. Lateral sewer

A. None of these

B. 1 in 120

D. 1 in 100

A. Filtration process is used

C. Neither A. nor B.

D. Both A. and B.

B. Discharge

C. Velocity of flow

D. Diameter of the sewer

A. Mechanized receipt

C. Mechanized segregation

D. Mechanized pulverising of refuse

A. Circular Imhoff double tanks with bottom hoppers

B. Circular septic tanks

D. Rectangular septic tanks

A. 1.425 D

C. 1.250 D

D. 1.350 D

A. Medium sewers are cleaned by cane rodding

B. Small sewers are cleaned by flushing

D. Medium sewers may be cleaned by pills

A. The period after which the entire area starts contributing to the runoff, is called the time of concentration

C. The maximum rate of storm runoff is called peak drainage discharge

D. Rational method of estimating peak run off, may be used precisely for areas less than 50 hectares

A. Chemical for lowering B.O.D.

C. Base material for paints

D. Building material

A. 15C

B. 0C

D. 25C

A. Septic tanks are generally provided a detention period of 12 to 36 hours

B. Septic tanks are completely covered and high vent shafts are provided for the escape of foul gases

D. Septic tanks are horizontal continuous flow type of sedimentation tanks

A. Weight

B. Size

D. Shape

B. Lateral sewers

C. Main sewers

D. Branch sewers

A. The screenings are disposed off either by burning or by burial or by dumping

C. The materials separated by screens, is called screenings

D. The process of burning the screenings, is known as compositing

A. 30 40 years

B. 5 10 years

D. 40 50 years

B. 150 mg/l

C. 50 mg/l

D. 100 mg/l

B. One pipe

C. Two pipes

D. Four pipes

A. d (0.285d + 0.011H)/Q

C. d (0.022d + 0.085H)/Q

D. d (0.785d + 0.011H)/Q

A. None of these

B. Potassium permanganate

D. Phenol-di -sulphuric acid potassium hydroxide

A. Detention period is 2 hours

B. The velocity of flow is restricted to 0.30 m/minute

C. The shape is rectangular

A. r/R = [1

B. d/D = (1

C. a/A

A. Hardness

B. Sediments

C. Suspended solids

A. 1500 litres/km/cm

B. 1000 litres/km/cm

D. 500 litres/km/cm

A. Sullage

C. None of these

D. Liquid waste

B. 3 ppm

C. 5 ppm

D. 10 ppm

A. G.I. pipes

B. Stone ware pipes

D. C.I. pipes

A. Four times the average demand

B. Average demand

C. Twice the average demand

B. 212 cu.m

C. 204 cu.m

D. 208 cu.m

A. 150 m

B. 100 m

C. 200 m

A. Weight of the back fill

C. Weight of the pipe

D. Superimposed traffic loads

A. All of these

C. 100 mm dia.

D. 150 mm dia.

B. Less than 0.01 mm

C. Less than 0.05 mm

D. Less than 0.1 mm

A. Liberation of nitrogen-formation of nitrates-formation of nitrites-liberation of ammonia

B. Liberation of nitrogen-liberation of ammonia-formation of nitrites- formation of nitrates

D. Formation of nitrates-formation of nitrites-liberation of nitrates-liberation of nitrates

A. 6

B. 6.5

C. 7

B. The outlet invert level is kept 5 to 7.5 cm below the inlet invert level

C. A gap of 7.5 cm between the bottom of the covering slab and the top level of scum is provided

D. The minimum width of septic level is 90 cm

A. O3

B. CO2

C. SO2

B. It is alkaline

C. It is acidic

D. None of these

A. More than 6

B. Less than 6

C. Less than 7

B. 400 mg/l

C. 200 mg/l

D. 100 mg/l

A. Carbondioxide

B. Hydrogen sulphide

C. Methane

A. D = 0.94 D

B. D = 0.74 D

C. D = 0.64 D

A. Parallel to the direction of flow

B. None of these

C. Perpendicular to the direction of flow

B. Cast iron

C. R.C.C.

D. P.C.C.

A. Tanks provided with self- cleansing screens

B. Improved version of grit chambers

D. Those from which sludge is skimmed out

A. 1065 mm

C. 1075 mm

D. 1045 mm