The microbial organisms named "Pseudomonas sp. LK-14" were isolated from farm land and shallow river sediment, activated, augmented and identified; which were using 2,4-D (2,4-Dichlorophenoxyacetic acid) as a sole carbon source and energy source. 3,4-D removal efficiency of LK-14 with 2,4-D sole carbon source (reactor S) were higher than that of Activated Slugde with 2,4-D sole carbon source (reactor A). Dynamic bioligical reaction kinetic parameters (sole carbon source was 2,4-D) obtained from batch reactor experiments were μlnax 0.008hr-1, Ks24D 26.95mg/L, Ks24D 1.75 hr-1 Y24D 0.10 for Activated Sludge. Using these parameters, we could predict the behav-iors of 2,4-D substrate and microbial popula-tion behavior entering into wastewater treatment plants by using unsteady states dynamic simulation modeling technique.