Question

QUESTION 4 horizontal flow grit chamber with rectangular x-section for treating maximum sewage flow of 10 MIld. Assume the particles settling velocity is 2.4 cm/sec, B is 0.06, fis 0.03 and particles diameter (D) is 0.02 cm. Also, take width of chamber as 1.0 m, free board as 0.3 m, grit accumulation depth as 0.25 m, specific gravity (SG) of particles as 2.65 and 2 [30] Design a mextra length for inlet and outlet works.

Answer 1

given data (Q) Sewage flow 1OMLD Panticle Setling Velocity (Vs) 2.4 Cm/s (d) Particle dia width af the chamben (B) 1m (F.B) Free board O.3m grit accutrulation dlepth Specific gravity (S) Q.65 L-002A10 K9-m/s 2 Viscosity of fluid Assume density 1000 K/m3 [SOR] Surface ovenflo Yale Step I Removal 100% For SOR VS Vs Qo 4 Cm/s SOR = =O.oa4m/S flow Yate (Q) SOR = AYea L. B) 10χι /exω) = O.0a.4 LX 1

L = 4.83m Leryth of channd 5m setng chambe 5m Length of PYovide Lenyth for Inlet and autle t given that am exta S+2=7m Total Length of chamben Delention time [DT Step &: Qmin OT A $Sume L.B. H OT 7X1XH 120 (Sec O.1157 H 1.984m PYovide dept of chamben 9yit accumulation depth m+ o.8a5m +o.3 m oVenall depth Free boand Settling velocthy (Vs) Step 3: gd Pe-fu) 18 u (2650 -1000) 9.81 X 18X 1.002xXO O.0358 m/S 3.586n/s Q.4 cm/S Hence ok

O 3m Free boand Inlet am Outlet O.asm 1m 5m