title: Influence of discontinuing feeding degradable cosubstrate on the performance of a fluidized bed bioreactor treating a mixture of trichlorophenol and phenol.
abstract: The purpose of our research was to evaluate the effect of eliminating supplementation of sucrose to the reactor influent on the performance of a lab scale partially-aerated methanogenic fluidized bed bioreactor (PAM-FBBR). Two operational stages were distinguished: in the first stage the influent contained a mixture of 120/30/1000 mg/L of 2,4,6-trichlorophenol/phenol/COD-sucrose (TCP/Phe/COD-sucrose); in the second stage only the xenobiotic concentrations were the same 120/30 mg/L of TCP/Phe whereas sucrose addition was discontinued. Removal efficiencies of TCP, Phe, and COD were very high and close for both stages; i.e., η(TCP): 99.9 and 99.9%; η(Phe): 99.9 and 99.9%; η(COD) = 96.46 and 97.48% for stage 1 and stage 2, respectively. Traces of 2,4,6 dichlorophenol (0.05 mg/L) and 4-chlorophenol (0.07-0.26 mg/L) were found during the first 15 days of operation of the second stage, probably due to the adaptation to no co-substrate conditions. Net increase of chloride anion Cl(-) in effluent ranged between 59.5 and 61.5 mg Cl(-)/L that was very close to the maximum theoretical concentration of 62.8 mg Cl(-)/L. PCR-DGGE analysis revealed a richness decrease of eubacterial domain posterior to sucrose elimination from the influent whereas archaeal richness remained almost the same. However, the bioreactor performance was not negatively affected by discontinuing the addition of co-substrate sucrose. Our results indicate that the application of PAM-FBBR to the treatment of groundwaters polluted with chlorophenols and characterized by the lack of easily degradable co-substrates, is a promising alternative for on site bioremediation.
authors.affiliation: Environmental Biotechnology and Renewable Energies Rand D Group, Dept Biotechnology and Bioengineering, CINVESTAV del IPN, PO Box 14-740, 07000 México DF, Mexico. hectorpoggi2001@gmail.com
authors.forename: Héctor M
authors.initials: HM
authors.lastname: Poggi-Varaldo
authors.forename: Juan D
authors.initials: JD
authors.lastname: Bárcenas-Torres
authors.forename: Cuauhtémoc U
authors.initials: CU
authors.lastname: Moreno-Medina
authors.forename: Jaime
authors.initials: J
authors.lastname: García-Mena
authors.forename: Claudio
authors.initials: C
authors.lastname: Garibay-Orijel
authors.forename: Elvira
authors.initials: E
authors.lastname: Ríos-Leal
authors.forename: Noemí
authors.initials: N
authors.lastname: Rinderknecht-Seijas
mesh_terms: D019149:Bioreactors; D002733:Chlorophenols / Q000378:metabolism*; D019800:Phenol / Q000378:metabolism*; D013395:Sucrose / Q000378:metabolism
chemical_list: D002733:Chlorophenols; D019800:Phenol; D013395:Sucrose; C024564:2,4,6-trichlorophenol