Design the structural components of a dual-media rapid filter for a nearby city. Provide

(a) clean bed headloss

(b) backwash velocity

(c) depth of expanded media

(d) number of filter beds

(e) area of an individual filter bed

(f) plan dimensions

(g) backwash trough layout

(h) maximum backwash water trough flow rate

(i) backwash trough dimensions

(j) backwash trough weir elevation above the undisturbed bed

(k) backwash water and tank volume

(l) maximum allowable filtration head loss

(j) depth of filter box and

(k) backwash tank low water elevation

The maximum day flow rate is 8700 m3 /d. The design criteria and sand analysis are given below. Assume a 375 mm diameter pipe from the gullet is to carry the wash water at a velocity of 1.2 m/s. Verify that the sand meets the recommendations for E and U. Adjust the grain size distribution if the sand does not meet the specification. Depth = 0.5 m, filtration rate = 150 m3 /d-m2 , sand specific gravity = 2.65, shape factor = 0.75, stratified bed porosity = 0.4, water temperature 10OC, trial backwash velocity = 65 m/h, trial gullet width =0.5 m, underdrain = 30 cm deep filter block with 1 mm orifice, gravel support = 32 cm in 4 layer.

Question 3 (filtration practice) Design the structural components of a dual-media rapid filter for a nearby city. Provide (a) clean bed headloss (b) backwash velocity (c) depth of expanded media (d) number of filter beds (e) area of an individual filter bed, (f) plan dimensions, (g) backwash trough layout, (h) maximum backwash water trough flow rate (i) backwash trough dimensions, (j) backwash trough weir elevation above the undisturbed bed, (k) backwash water and tank volume, (1) maximum allowable filtration head loss (i) depth of filter box and (k) backwash tank low water elevation The maximum day flow rate is 8700 m/d. The design criteria and sand analysis are given below. Assume a 375 mm diameter pipe from the gullet is to carry the wash water at a velocity of 1.2 m/s. Verify that the sand meets the recommendations for E and U. Adjust the grain size distribution if the sand does not meet the specification. Depth = 0.5 m, filtration rate = 150 m/d-m, sand specific gravity = 2.65, shape factor = 0.75, stratified bed porosity = 0.4, water temperature 10C, trial backwash velocity = 65 m/h, trial gullet width=0.5 m, underdrain = 30 cm deep filter block with 1 mm orifice, gravel support = 32 cm in 4 layer. Sand analysis US standard Sieve No Mass percent retained 10-14 2.0 14-20 16.5 20-25 15.4 25-30 38.2 30-35 15.9 35-40 6.5 40-50 4.4 50-60 1.0 *Geometric mean diameter of successive sieves is dg = (dd2.0.5 = Question 3 (filtration practice) Design the structural components of a dual-media rapid filter for a nearby city. Provide (a) clean bed headloss (b) backwash velocity (c) depth of expanded media (d) number of filter beds (e) area of an individual filter bed, (f) plan dimensions, (g) backwash trough layout, (h) maximum backwash water trough flow rate (i) backwash trough dimensions, (j) backwash trough weir elevation above the undisturbed bed, (k) backwash water and tank volume, (1) maximum allowable filtration head loss (i) depth of filter box and (k) backwash tank low water elevation The maximum day flow rate is 8700 m/d. The design criteria and sand analysis are given below. Assume a 375 mm diameter pipe from the gullet is to carry the wash water at a velocity of 1.2 m/s. Verify that the sand meets the recommendations for E and U. Adjust the grain size distribution if the sand does not meet the specification. Depth = 0.5 m, filtration rate = 150 m/d-m, sand specific gravity = 2.65, shape factor = 0.75, stratified bed porosity = 0.4, water temperature 10C, trial backwash velocity = 65 m/h, trial gullet width=0.5 m, underdrain = 30 cm deep filter block with 1 mm orifice, gravel support = 32 cm in 4 layer. Sand analysis US standard Sieve No Mass percent retained 10-14 2.0 14-20 16.5 20-25 15.4 25-30 38.2 30-35 15.9 35-40 6.5 40-50 4.4 50-60 1.0 *Geometric mean diameter of successive sieves is dg = (dd2.0.5 =