Formaldehyde biodegradation and its effect on the denitrification process.
Simultaneous formaldehyde biodegradation and denitrification in batch assays and in a continuous lab-scale reactor were studied. In batch assays, initial biodegradation rates between 0.7 and 3.3 g CKH2O g VSS(-1) d(-1) were obtained at formaldehyde concentrations between 300 and 2150 mg l(-1). The denitrification process was affected by the presence of formaldehyde. The nitrite accumulation increased with the initial formaldehyde concentration. In the continuous reactor, removal efficiencies above 98.5% were obtained at formaldehyde loading rates between 0.37 and 2.96 kg COD m(-3) d(-1) (625-5000 mg CH2O l(-1)). Formaldehyde removal led to the appearance of methanol and formic acid in the medium. Denitrification process was almost complete (around 99.7%) at nitrogen loading rates up to 0.44 kg N-NO3- m(-3) d(-1). Nitrite occasionally appeared in the effluent at concentrations less than 2.9 mg l(-1). The composition of the biogas indicated that denitrification and methanogenesis occurred simultaneously in the same unit.
Eiroa
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Chemical Engineering Laboratory, Faculty of Sciences, University of A Coruña Alejandro de la Sota n 1, 15008-A Coruña, Spain.
Vilar
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Kennes
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Veiga
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MC
D019149:Bioreactors; D005557:Formaldehyde / Q000378:metabolism*; D007220:Industrial Waste; D009566:Nitrates / Q000378:metabolism*; D017680:Potassium Compounds / Q000378:metabolism*; D014865:Waste Disposal, Fluid; D014874:Water Pollutants, Chemical / Q000378:metabolism*
D007220:Industrial Waste; D009566:Nitrates; D017680:Potassium Compounds; D014874:Water Pollutants, Chemical; D005557:Formaldehyde; C023844:potassium nitrate