Bioregeneration of granular activated carbon loaded with 2,4-D

The feasibility of using whole cell microorganisms to regenerate spent gran ular activated carbon (GAC) was investigated. Regeneration of 2,4-D loaded activated carbon by Pseudomonas isolates was observed for bioregeneration t imes of 18-96 hours, and initial bacterial concentrations of 7.17x10(5) to 7.17x10(7) CFU/mL. Pore surface recovery decreased with increasing initial bacterial concentrations suggesting that bacteria may have blocked the pore s. Regeneration efficiency of larger pore diameter GAC was found to be high er, indicating that bacteria could not access 2,4-D loaded sites where the pore diameter was small However, at high initial bacterial concentrations, increase in bioregeneration time increased pore surface recovery indicating that intermediate metabolite products (IMPs) of 2,4-D were further metabol ized. The bioregeneration process changed the adsorption equilibrium and ad sorption kinetics characteristics of the original activated carbon. The car bon pore structure was found to influence the process of bioregeneration.