Standards of Dilution for Discharge of Wastewaters into Rivers
Cs = The concentration of sewage in mg/lit.
Qs = A flow rate of sewage in m3/sec or lit/sec.
CR = The concentration of the river in mg/lit.
QR = Flow rate (discharge in m3/sec or lit/sec.
Cmix = The concentration of the mixture.
Saturation D.O at 20oC → 9.2 mg/lit.
Saturation D.O at 30oC → 7.6 mg/lit.
Saturation D.O at 0oC → 14.6 mg/lit.
ab = cd
TOD = Theoretical oxygen demand
BOD = Biological oxygen demand
COD = Chemical oxygen demand
(BOD)u = Ultimate BOD (Yu)
Dt = D.O deficit in mg/lit after t days.
L = Ultimate first stage BOD of the mix at a point of waste discharge in mg/lit.
Do = Initial oxygen deficit of the mix at the mixing point in mg/lit.
kR = Reoxygenation constant
kD = Deoxygenation constant
f = Self-purification constant
tC = Critical time at which minimum dissolved oxygen occurs i.e.
DC = Critical maximum oxygen deficit.