The results of empirical analysis for Chinese cities show that the allometric growth exponent in the equation for the variation rate of passenger demand volume on rail is greater than the predicted value of 1/4 in metabolic ecology,whereas the allometric growth relationship is not so evident in the equation for the variation rate of passenger demand volume on road.

We introduced the progress in the application of allometric relationships in biomass estimation in recent decade,and then discussed some statistical issues in model fitting process.

Sensitivity analysis showed that the performance of activated sludge system was affected remarkably by heterotrophic decay rate, heterotrophic maximum specific growth rate and autotrophic maximum specific growth rate, so these parameters were studied.