Simultaneous nitrification and p-cresol oxidation in a nitrifying sequencing batch reactor.
The tolerance, kinetic behavior and oxidizing ability of a nitrifying sludge exposed to different initial concentrations of p-cresol (25-150mg/l) were evaluated in a sequencing batch reactor (SBR) fed with 200mg NH(4)(+)-N/ld. The nitrifying SBR operated up to 300mg/ld of p-cresol, achieving simultaneously the complete ammonium oxidation to nitrate and the total consumption of p-cresol and its transitory intermediates from the culture. p-Cresol induced a significant decrease in the values for specific rates of ammonium consumption, showing that the ammonium oxidation pathway was mainly inhibited. After 7 months of operation in SBR, the specific rates of NH(4)(+)-N oxidation, NO(3)(-)-N formation, and total organic carbon consumption were 0.6g NH(4)(+)-N/g microbial protein-Nh, 0.3g NO(3)(-)-N/g microbial protein-Nh, and 0.24g total organic carbon/g microbial protein h, respectively. The microbial growth rate was always low (maximum value of 12.2+/-0.4mg protein-N/ld) and settleability of the sludge was good with sludge volume index values lower than 21ml/g. The oxidation of p-cresol and its intermediates was carried out faster throughout the cycles and nitrification inhibition decreased with the number of cycles.
Texier
A-C
AC
Universidad Autónoma Metropolitana-Iztapalapa, Div. CBS, Departamento de Biotecnología, Av. San Rafael Atlixco 186, Col. Vicentina, C.P. 09340, México, DF.
Gomez
J
J
D019149:Bioreactors / Q000382:microbiology; D003408:Cresols / Q000378:metabolism*; D007700:Kinetics; D009566:Nitrates / Q000378:metabolism*; D010084:Oxidation-Reduction; D012722:Sewage / Q000382:microbiology*; D014865:Waste Disposal, Fluid / Q000379:methods*
D003408:Cresols; D009566:Nitrates; D012722:Sewage; C032538:4-cresol