$2.$

Dispersed plug flow through a long narrow chlorination tank was analyzed $b$

injecting a pulse input of a dye tracer in the influent. The tracer response curvi

is drawn in Fig. $10\mathrm{.}12,$ and the measured $t$ and $C$ values are listed in the first two

columns of Table $10\mathrm{.}2.$ The theoretical detention time at the test flowrate was $50$

min $.$ Calculate the dispersion number and the time ratios of $\frac{t_{50}}{t_R}$ and $\frac{t_{90}}{t_{10}}.$

Figure $10\mathrm{.}12$ Tracer response curve from injecting a pulse input of dye into the

influent of a long narrow chlorination tank. $[$Adapted from D$.$ M$.$ Marske and J$.$ D$.]$