Civil Engineering - Waste Water Engineering - Discussion

27. 

A sewer pipe contains 1 mm sand particles of specific gravity 2.65 and 5 mm organic particles of specific gravity 1.2, the minimum velocity required for removing the sewerage, is

[A]. 0.30 m/sec
[B]. 0.35 m/sec
[C]. 0.40 m/sec
[D]. 0.45 m/sec
[E]. 0.50 m/sec.

Answer: Option D

Explanation:

No answer description available for this question.

Saroj said: (Nov 20, 2015)  
How come answer please tell me someone?

Saroj said: (Nov 20, 2015)  
How come this answer?

What formula use in solve this question please tell me?

Neethu said: (Nov 29, 2015)  
Sqr(8k/f*(s-1)*g*d).

K = Constant, for clean inorganic solids = 0.04 and for organic solids = 0.06.

f' = Darcy Weisbach friction factor (for sewers = 0. 03).

Ss = Specific gravity of sediments.

g = Gravity acceleration.

d' = Diameter of grain, m.

Sunil Gupta said: (Sep 12, 2016)  
The velocity required removing sewage = size of sand particle * specific gravity of sand/(specific gravity of organic mater *size of organic matter).

V = 1 * 2.65/ (5 * 1.2) = 0.441666 = 0.45 m/s.

Baloch said: (Nov 1, 2016)  
Thanks @Sunil Gupta.

Anchal said: (Nov 3, 2016)  
Thanks @Sunil.

Ravi Yadav said: (Jan 5, 2017)  
@ALL.

Use Neethu's formulae for solve this.

Thanks @Neethu.

Ovizit Saha said: (Jul 13, 2017)  
Thanks @ Sunil Gupta.

Dheerak Singh said: (Sep 16, 2017)  
V=√k(gd (s-1)).
=√4.5 (10*.005 (1.2-1)).

Dipan said: (Apr 4, 2018)  
No, it is wrong @Sunil Gupta.

@Neethu

Thanks for your information.

This is the correct self-cleaning velocity and we get this formula 0.4 for organic particle and .42 for sand but the minimum self-cleaning velocity is 0.45 so we take the value 0.4.

Randos said: (Apr 18, 2018)  
Check the unit. @Sunil.

Pavani said: (Jun 25, 2018)  
According to me, it is 0.5.

Hemanth said: (Jul 1, 2018)  
@All

Here, s sand particle up to 1mm and organic particles up to 5mm, there is a condition for this one min velocity of 0.45 m/sec and Max 0.9m/sec.

Hence no need to calculate anything.
And @Neethu, the correct formula is;
Vs=√((8k/f)*(s-1)*g*d) this is the right one.

Nagdive said: (Aug 19, 2018)  
Thank you @Sunil And @Hemanth.

Masoom said: (Mar 12, 2019)  
Thank you @Sunil.

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