Parameter & design criteria*

Equation* & obtained value

Design flow, Q_ave = 30,000 m³/day

Surface loading rate, SLR = 40 m³/m²・d

$\text{Area}\left(A\right)=\frac{Q}{\text{SLR}}=750{\mathrm{m}}^2$

No. of Primary sedimentation tank = 2

Depth = 3 m

Diameter: $D=\sqrt{\frac{4A}{\pi }=}22\text{m}$

$\text{Weirloadingrate},\text{WLR}=217{\text{m}}^3/\text{m}\text{.d}$

Empirical constants, a, b: 0.018, 0.020 for BOD

0.0075, 0.014 for TSS

expected removal efficiency,

$R=\frac{t}{a+b.t}=33.5\%\text{BOD},55.3\%\text{TSS}$