immediate ozone demand; and k, the decay kinetic constant, due to overall ozone consumption
by moderate or slow reactions. Both values have been calculated from the plot of the residual
ozone versus TOD. When the TOD exceeds X, residual ozone appears in the effluent and its
concentration increases with increasing TOD. The slope of the plot (Kd) is the function of the
hydraulic residence time in the reactor, its hydraulic characteristics and k, which can be
determined according to the following equation: