p-Cresol mineralization and bacterial population dynamics in a nitrifying sequential batch reactor

摘要

The ability of a nitrifying sludge to oxidize p-cresol was evaluated in a sequential batch reactor(SBR).p-Cresol was first transformed to p-hydroxybenzaldehyde and p-hydroxybenzoate,which were later mineralized.The specific rates of p-cresol consumption increased throughout the cycles.The bacterial population dynamics were monitored by using denaturing gradient gel electrophoresis(DGGE)and sequencing of DGGE fragments.The ability of the sludge to consume p-cresol and intermediates might be related to the presence of species such as Variovorax paradoxus and Thauera mechernichensis.p-Cresol(25 to 200 mg C/L)did not affect the nitrifying SBR performance(ammonium consumption efficiency and nitrate production yield were close to100%and 1,respectively).This may be related to the high stability observed in the nitrifying communities.It was shown that a nitrifying SBR may be a good alternative to eliminate simultaneously ammonium and p-cresol,maintaining stable the respiratory process as the bacterial community.