Biodegradation and effect of formaldehyde and phenol on the denitrification process.
Formaldehyde and phenol biodegradation during the denitrification process was studied at lab-scale, first in anoxic batch assays and then in a continuous anoxic reactor. The biodegradation of formaldehyde (260 mgl(-1)) as single carbon source and at phenol concentrations ranging from 30 to 580 mgl(-1) was investigated in batch assays, obtaining an initial biodegradation rate around 0.5g CH(2)OgVSS(-1)d(-1). With regard to phenol, its complete biodegradation was only observed at initial concentrations of 30 and 180 mgl(-1). The denitrification process was inhibited at phenol concentrations higher than 360 mgl(-1). Studies were also done using a continuous anoxic upflow sludge blanket reactor in which formaldehyde removal efficiencies above 99.5% were obtained at all the applied formaldehyde loading rates, between 0.89 and 0.14g COD (CH(2)O)l(-1)d(-1). The phenol loading rate was increased from 0.03 to 1.3g COD (C(6)H(6)O)l(-1)d(-1). Phenol removal efficiencies above 90.6% were obtained at phenol concentrations in the influent between 27 and 755 mgl(-1). However, when the phenol concentration was increased to 1010 mgl(-1), its removal efficiency decreased. Denitrification percentages around 98.4% were obtained with phenol concentrations in the influent up to 755 mgl(-1). After increasing phenol concentration to 1010 mgl(-1), the denitrification percentage decreased because of the inhibition caused by phenol.
Eiroa
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Chemical Engineering Laboratory, Faculty of Sciences, University of A Coruña, Rúa Alejandro de la Sota no. 1, 15008-A Coruña, Spain.
Vilar
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A
Amor
L
L
Kennes
C
C
Veiga
M C
MC
D001673:Biodegradation, Environmental; D019149:Bioreactors; D005557:Formaldehyde / Q000737:chemistry / Q000378:metabolism*; D009573:Nitrites / Q000737:chemistry* / Q000378:metabolism; D019800:Phenol / Q000737:chemistry / Q000378:metabolism*; D013997:Time Factors; D014865:Waste Disposal, Fluid / Q000379:methods; D018508:Water Purification / Q000379:methods*
D009573:Nitrites; D005557:Formaldehyde; D019800:Phenol