Simultaneous nitrification and formaldehyde biodegradation in an activated sludge unit.
The simultaneous removal of formaldehyde and ammonium in a lab-scale activated sludge unit was investigated. The unit was operated at a hydraulic retention time of 2.4 days with an ammonium concentration in the influent of 350 mg NH4+-N/L, maintaining the ammonium loading rate at 0.15 g NH4+-N/Ld during the operation time. However, the applied organic loading rate was increased stepwise by increasing the formaldehyde concentration from 26 up to 3168 mg/L, corresponding to 0.01-1.40 g COD/Ld. High formaldehyde removal efficiencies, around 99.5% (+/-0.38), were maintained at all the formaldehyde concentrations. Ammonium removal was also very high during the operation period, around 99.9% (+/-0.01). The ammonium concentration in the effluent was lower than 0.1 mg NH4+-N/L at all applied organic loading rates, indicating that there was no inhibition of nitrification by formaldehyde.
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.
Kennes
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C
Veiga
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MC
D000641:Ammonia / Q000378:metabolism*; D001419:Bacteria / Q000378:metabolism*; D001673:Biodegradation, Environmental; D019149:Bioreactors; D005557:Formaldehyde / Q000378:metabolism*; D012722:Sewage / Q000382:microbiology*; D013997:Time Factors; D014865:Waste Disposal, Fluid / Q000379:methods*
D012722:Sewage; D005557:Formaldehyde; D000641:Ammonia