Model-based evaluation of two BNR processes--UCT and A2N.
The activity of denitrifying P-accumulating bacteria (DPB) has been verified to exist in most WWTPs with biological nutrient removal (BNR). The modified UCT process has a high content of DPB. A new BNR process with a two-sludge system named A2N was especially developed to exploit denitrifying dephosphatation. With the identical inflow and effluent standards, an existing full-scale UCT-type WWTP and a designed A2N process were evaluated by simulation. The used model is based on the Delft metabolical model for bio-P removal and ASM2d model for COD and N removal. Both processes accommodate denitrifying dephosphatation, but the A2N process has a more stable performance in N removal. Although excess sludge is increased by 6%, the A2N process leads to savings of 35, 85 and 30% in aeration energy, mixed liquor internal recirculation and land occupation respectively, as compared to the UCT process. Low temperature has a negative effect on growth of poly-P bacteria, which becomes to especially appear in the A2N process.
Hao
X
X
The Research Centre for Ecological Economics and Environmental Technology, Shanxi University of Finance and Economics, Taiyuan, People's Republic of China.
Van Loosdrecht
M C
MC
Meijer
S C
SC
Qian
Y
Y
D000465:Algorithms; D000693:Anaerobiosis; D001419:Bacteria / Q000378:metabolism*; D019149:Bioreactors; D004734:Energy Metabolism; D008954:Models, Biological; D009566:Nitrates / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism; D010758:Phosphorus / Q000378:metabolism*; D012722:Sewage / Q000737:chemistry / Q000382:microbiology*; D014865:Waste Disposal, Fluid / Q000379:methods; D018508:Water Purification / Q000379:methods*
D009566:Nitrates; D012722:Sewage; D010758:Phosphorus; D009584:Nitrogen; D010100:Oxygen