Answer
given,
average flow rate = 0.3 m³/s
peak flow rate = 1 m³/s
width to depth ratio = 1.5 : 1
detention time = 3.5 min
average depth = 3 m
aeration rate = 0.4 m³/min/m
dimensions of grit chamber = ?
volume of grit chamber = [tex]\dfrac{1 \times 3.5 \times 60}{2}[/tex]
= 105 m³
average depth = 3 m
width-to-depth ratio = 1.5:1,
width = 1.5 × 3 = 4.5 m
length of the grit chamber = [tex]\dfrac{105}{3\times 4.5}[/tex]
= 7.78 m
increase length by 20% to account for inlet and outlet of the tank
length = 1.2 × 7.78 = 9.34 m
dimension of grit chamber = 9.34 m × 4.5 m × 3 m
air required = aeration rate × length
= 0.4 m³/min /m × 9.34
= 3.736 m³/min
