Table 1
Comprehensive approach towards WWT system designa
| Sedimentation tank | Cascade aeration | Trickling/adsorption filter | Disinfection unit |
|---|---|---|---|
| Overflow rate estimation = Vo = Q/L × W Area = A = Q/Vo L × W or πd2/4 Retention time = tr = V/Q Depth = D = tr × Q/A | Deficit ratio = R = Cs – Co/ Cs – C Cascade height = H = R − 1/0.11 a b (1 + 0.046 T) Step length, height and inclination angle from Table 5–34 using ‘H’ (Metcalf & Eddy 2003) | BOD loading = W = Q × BODinf F = 1 + R/(1 + R/10)2 Efficiency ENRC = 100/1 + 0.4432  Assume depth, find diameter  adsorption Filter = V/m = qe /Co-Ce | CCT length = Q × contact time/width × depth, V = Q/width × depth NR = 4VR/vo R = A/P D = coefficient of dispersion = 1.01vo (NR)0.87 dispersion number = D·t/L2 |
| Sedimentation tank | Cascade aeration | Trickling/adsorption filter | Disinfection unit |
|---|---|---|---|
| Overflow rate estimation = Vo = Q/L × W Area = A = Q/Vo L × W or πd2/4 Retention time = tr = V/Q Depth = D = tr × Q/A | Deficit ratio = R = Cs – Co/ Cs – C Cascade height = H = R − 1/0.11 a b (1 + 0.046 T) Step length, height and inclination angle from Table 5–34 using ‘H’ (Metcalf & Eddy 2003) | BOD loading = W = Q × BODinf F = 1 + R/(1 + R/10)2 Efficiency ENRC = 100/1 + 0.4432 Assume depth, find diameter adsorption Filter = V/m = qe /Co-Ce | CCT length = Q × contact time/width × depth, V = Q/width × depth NR = 4VR/vo R = A/P D = coefficient of dispersion = 1.01vo (NR)0.87 dispersion number = D·t/L2 |
aDetails of design symbols used in formulas are provided in respective design section.