# Civil Engineering - Waste Water Engineering - Discussion

### Discussion :: Waste Water Engineering - Section 1 (Q.No.27)

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.

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.