Quantitative bioregeneration of granular activated carbon loaded with phenol and 2,4-dichlorophenol

Lignite based granular activated carbon of 20x30 mesh size was used to inve stigate the extent of bioregeneration of phenol and 2,4-DCP in a batch syst em. The adsorption Isotherm fits very well with the Freundlich isotherm and it is apparent that 2,4-DCP is more adsorbable than phenol. The degree of reversible adsorption for phenol and 2,4-DCP were 32.9 and 10.6 Sb, respect ively. The low percentages of their reversibility meant that the adsorption phenomena of both phenol and 2,4-DCP were not fully physicosorption. The m icroorganisms can regenerate 31.4 % (21.2 mg g(-1)) of GAC loaded with phen ol and 14.3 % (24.8 mg g(-1)) of GAC loaded with 2,4-DCP over a period of 7 -10 days. The bioregeneration of phenols closely followed the first order k inetics with the rate constant of 0.046 day(-1) at initial phenol concentra tion of 100 mg l(-1) and biomass concentration of 20 mg l(-1) MLVSS. The ra te constant was 0.021 day(-1) at initial 2,4-DCP concentration of 200 mg l( -1) and 200 mg l(-1)' MLVSS. In addition, the increasing in initial concent ration of biomass in the solution shortened the time required to reach the asymptotic limit on the bioregeneration bur rendered little impact on the b ioregeneration percentage.