Biological denitrifying phosphorus removal in SBR: effect of added nitrate concentration and sludge retention time.
Optimizing anoxic biological phosphorus removal in the anaerobic-anoxic sequencing batch reactor (A2 SBR) was observed to depend on two parameters: the amount of added nitrate and the sludge retention time (SRT). The concentration of 120 mg N-NO3.l-1 in the anoxic medium and the SRT of 15 days were determined as optimal for a complete phosphorus removal in the A2 SBR. The reactor was supplied with synthetic wastewater containing 800 mg COD.l-1 acetic acid, 240 mg N-NH4.l-1 and 30 mg P-PO4.l-1. This study was completed by microscopic observations which revealed three morphological types of phosphate-accumulating bacteria (PAB).
Merzouki
M
M
INRA, Laboratoire de Biotechnologie de l'Environement (LBE), Avenue des Etangs, 11100 Narbonne, France.
Bernet
N
N
Delgenès
J P
JP
Moletta
R
R
Benlemlih
M
M
D001419:Bacteria / Q000378:metabolism; D019149:Bioreactors / Q000382:microbiology; D009566:Nitrates / Q000378:metabolism; D009584:Nitrogen / Q000302:isolation & purification*; D010758:Phosphorus / Q000302:isolation & purification*; D012722:Sewage / Q000382:microbiology; D013997:Time Factors; D014865:Waste Disposal, Fluid / Q000379:methods*
D009566:Nitrates; D012722:Sewage; D010758:Phosphorus; D009584:Nitrogen