Nitrification of high-strength ammonium wastewater by a fluidized-bed reactor.
A laboratory-scale fluidized-bed reactor with an external aeration loop was used for nitrification of high-strength ammonium wastewater (up to 500 mg NH4-N/L). The results demonstrated that the system is capable of handling ammonium removal rates of up to 2.5 kg NH4-N/m3 x d, while removal efficiencies were as high as 98% and independent of the applied ammonium loading rates. Ammonium loading rates higher than 2.5 kg NH4-N/m3 x d resulted in decreased ammonium removal efficiency. The data show that near complete ammonium removal occurred at DO concentrations as low as 0.3-0.5 mg/L. However, the nitrite-nitrogen fraction in the effluent increased from 3.5% to 23.2% when the DO dropped from 1.0 mg/L to approximately 0.4 mg/L, respectively. The high specific removal rates in this system are one order of magnitude higher than that of suspended-growth systems. This can reduce the supplementary reactor volumes required for nitrification to less than 10% of that needed in conventional activated sludge systems. These results clearly indicate the potential economic gains that could be achieved through implementation of this technology.
Botrous
A E F
AE
Department of Civil Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA. abotrous@unlnotes.unl.edu
Dahab
M F
MF
Miháltz
P
P
D018441:Biofilms; D019149:Bioreactors; D009584:Nitrogen / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D010100:Oxygen / Q000032:analysis; D000644:Quaternary Ammonium Compounds / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D012722:Sewage / Q000737:chemistry / Q000382:microbiology; D014865:Waste Disposal, Fluid / Q000379:methods*; D018508:Water Purification / Q000379:methods*
D000644:Quaternary Ammonium Compounds; D012722:Sewage; D009584:Nitrogen; D010100:Oxygen