Environmental Engineering (General Engineering) (SSC JE)

Total Questions: 50

21. In house water connection, ferrule is provided, which is a : [RRB JE 27.08.2015 (Shift-II) ]

Correct Answer: (b) right angled sleeve made of brass or gun metal
Solution:

In house water connection ferrule is provided for joining two pipes together and making the connection water tight.
• The ferrule is right angled sleeve made of brass or gun metal.

22. The prescribed permissible limit of chloride in drinking water is : [RRB JE 27.08.2015 (Shift-II) ]

Correct Answer: (c) 250 mg/l
Solution:

The prescribed permissible limit of chloride in drinking water is 250 mg/l and rejection limit of chloride in drinking water = 1000 mg/l.

23. The water treatment plants are generally designed for a period of : [RRB JE 27.08.2015 (Shift-II) ]

Correct Answer: (d) 15 years
Solution:

Design period of units-

24. The value of peak factor considered in the estimation of water demand for the population of 1,00,000 is– [RRB JE 27.08.2015 (Shift-III) ]

Correct Answer: (b) 2.50
Solution:


Here population is 100000 i.e, lies between 50001- 200000 So, peak factor is 2.5.

25. A water borne disease may be controlled by– [RRB JE 27.08.2015 (Shift-III) ]

Correct Answer: (a) Disinfection of water
Solution:

The process to killing pathogenic bacteria and safe to the public use its called disinfection.
Method of removing disinfection–

1. Physical method
 (a) Disinfection by boiling
(b) Disinfection by U-Vray 2.

Chemical method
(i) oxidizing chemicals (Cl₂, Br, I₂, O₃, KMNO₄, H₂O₂)
(ii) metal ions (Ag, Cu)
(iii) alkalis and acids

26. The colour in water is determined using instrument called– [RRB JE 27.08.2015 (Shift-III) ]

Correct Answer: (c) Tintometer
Solution:

Colour test– The intensity of colour in the water is measured using the colour matching technique in tintometer by Nessler's tube and it is expressed in terms of standard unit obtained by the addition of platinum in the form of chloroplatinate in 1 litre of pure water and is represented as TCU (True colour Unit).

27. The suspended solids present in surface water can be determined by [RRB JE 27.08.2015 (Shift-I) ]

Correct Answer: (a) Gravimetric test
Solution:

Suspended solids–
They are called as physical parameters and dissolved solids are considered as chemical parameters.
• Gravimetric test is calculated by suspended solids.
• Dissolved solids = total solids – Suspended solids.
• For suspended solids as per EPA is 30 ppm.

28. The disease caused by mercury is known as [RRB JE 27.08.2015 (Shift-I) ]

Correct Answer: (c) Minamta
Solution:

The disease caused by mercury is known as minamata. It is a neurological syndrome caused by mercury poisoning. Minamata disease was first discovered in Minamata city, Japan in 1956.

Note– Itai-ital disease caused by Cadmium Blue baby disease caused by Nitrates

29. Length to width ratio of rectangular sedimentation tank should be- [RRB JE 27.08.2015 (Shift-I) ]

Correct Answer: (c) 4 : 1
Solution:

A typical long rectangular tank has a length ranging from 4 times their width. The bottom is slightly sloped to facilitate sludge scraping.
The general dimension of a sedimentation tank are as follows–
Length (L) = 4 × B
Height = 3.5 to 5 m
Sludge depth = 0.8 m to 1.2 m
Free board = 0.5 m
Note–                             Detention period
For plain sedimentation = 4 to 8 hrs.
For sedimentation with coagulation = 2 to 4 hrs.

30. The average concentration of ozone in troposphere is [RRB JE 27.08.2015 (Shift-I) ]

Correct Answer: (b) 0.05 ppm
Solution:

Ozone is a reactive gas that is present in two layers of the atmosphere, the stratosphere and the troposphere up to 15 km. In the troposphere near the earth's surface, the natural concentration of ozone is about 0.02 - 0.05 ppm.