Threshold Odour Number (TON)
Vs = The volume of the sewage
VD = The volume of distilled water or odourless water.
Chemical Oxygen Demand
Theoretical Oxygen Demand
C6H6 + 7.5O2 → 6O2 + 3H2O
C6H12O6 + 6O2 → 6O2 + 6H2O
k = Rate constant signifying the rate of oxidation of organic matter and it depends upon the nature of organic matter and temperature. Its unit is per day.
Lt = O2 the equivalent of organic matter present after t days.
kD = Deoxygenation constant.
L = Organic matter present at t = 0
Yt = The total amount of organic matter oxidized int days i.e. BOD.
Yu = Ultimate B.O.D of days.
(viii) Laboratory Estimations of kD and L values
m = Slope of the line
C = Intercept of the line on the y-axis.
Relative Stability (s)
t20 = time in days at 20oC.
t37 = time in days at 37oC.