Population growth

Purity of water

Strength of sewage

Strength of sewage

Population equivalent is a measure of strength of sewage produced by a factory.

Boiling

Ozone treatment

Chlorination

Flocculation

Flocculation cannot kill any microorganisms. It is used to remove the suspended particles.

To balance the head loss

For removing bigger suspended matter in sewage

To balance fluctuating flows or concentrations

None of the above

The equalization tanks are provided to balance fluctuating flows or concentrations, temperature, pH value, etc

4 to 4.75 mm

2 to 4 mm

0.2 to 0.4 mm

0.05 to 0.1 mm

Effective size of filter sand in slow sand filter ranges from 0.2-0.35 mm Effective size of filter sand in slow sand filter ranges from 0.35-0.5 mm

The principle of continuity is satisfied at each joint

The principle of continuity is satisfied at each junction

There can be discontinuity in pressure

There can be discontinuity in velocity

One of the assumption used in solving a flow distribution problem using Hardy-Cross Method is that, continuity equation is satisfied at each junction

Growth rate is progressively increasing

Growth rate is constant

Percentage growth rate is increasing

Percentage growth rate is constant

Geometric increase method of population forecasting is based on the assumption that percentage growth rate is constant Arithmetic increase method of population forecasting is based on the assumption that growth rate is constant Incremental increase method of population forecasting is based on the assumption that growth rate is progressively increasing

Increases

Reduces

Has no change

None of the above

Shear lag effect occurs when an angle is connected to a gusset plate, one lug of angle is connected to the plate, whereas the other lug will be outstanding member. To reduce the shear lag, a lug angle will be connected below the angle section. This increases the length of connection, which causes the shear lag effect to reduce.

1.1 to 1.5

1.0 to 1.25

1.25 to 2.0

1.0 to 1.5

As per IS 800, the partial safety factor for materials γm is in the range 1.1 to 1.5

6 N/mm2

36 N/mm2

1 N/mm2

0 N/mm2

In post tensioning, when all the cables are simultaneously tensioned, loss due to elastic shortening will not occur. It occurs only when cables are tensioned step-by-step. Here there is only one tendon & hence there is no step-by-step tensioning of cables. Thus loss due to elastic shortening is zero

Elastic shortening

Friction

Anchorage slip

Relaxation

Losses due to elastic shortening, friction and anchorage slip are immediate losses whereas loss due to relaxation of steel occurs gradually over time

M45

M40

M35

M30

As per IS 1343, grade of concrete for pre-tensioned prestressed concrete shall be not less than M40

25 mm

20mm

5mm

10mm

As per IS 456:2000, minimum eccentricity to be considered in the design of a long RCC column is 20 mm

0.4 mg/l

4 mg/l

10 mg/l

12 mg/l

Solution Minimum DO required for aquatic life to survive in water is 4 ppm or 4 mg/l

200 m3

100 m3

2000 m3

1000 m3

Given, Q = 12 x 106 l/day = 12000 m3/day Volume = Q x detention period = 12000 x 2/24 = 1000 m3

Allowed to mix with settled sludge

Not allowed to mix with settled sludge

Allowed to mix with activated sludge

Not allowed to mix with activated sludge

In Imhoff tank, the incoming sewage is not allowed to mix with settled sludge. In septic tank, the incoming sewage is allowed to mix with settled sludge.

Hydraulic Retention Time

Solid Retention Time

Sludge Retention Time

Blanket Retention Time

Ratio of reactor volume (V) to flow rate (Q) is called Hydraulic Retention Time or Hydraulic Detention Time.

0.64%

0.35%

0.15%

0.12%

As per IS 3370-2:2009, minimum reinforcement required for RCC tank walls, using mild steel is 0.64% and minimum reinforcement required for RCC tank walls, using HYSD bars is 0.35%

Mild exposure condition

Moderate exposure condition

Severe exposure condition

Very severe exposure condition

As per IS 3370-1:2009, Cl 4, parts of the structure retaining the liquid or enclosing the space above the liquid shall be considered as subject to severe condition as per IS 456

M20

M25

M30

M35

As per IS 3370-1:2009, Table 1 (notes), for small capacity tanks up to 50m3 at locations where there is difficulty in providing M30 grade concrete, the minimum grade of concrete may be taken as M25

20 mm

25 mm

30 mm

40 mm

As per IS 456:2000, Cl:26.4.2.1, for columns of minimum dimension of 200 mm or under, whose reinforcing bars do not exceed 12mm, a nominal cover of 25 mm may be used