Phosphorus removal and greenhouse gas N2O emission in a lime-induced aerobic sludge granule process.
Aerobic sludge granulation was achieved in an activated sludge process continuously fed with lime (Ca2+ 100 mg l(-1) influent) every other day. Eighteen days after lime addition, activated sludge granules with the size of 0.5-2.2 mm were formed, which occupied 10-25% of total sludge volume. Sludge volume index (SVI) was reduced to an average of 50 ml g(-1), which increased average sludge concentration to 3.6-5.0 g VSS l(-1), 1.6-2.1 times of that of control. Greenhouse gas N2O emission was also significantly reduced: N2O concentration from the lime-addition reactor was 5-15 ppmv, 47-61% of that of control, Effluent PO4-P concentration was generally lower than 1 mg l(-1) when average influent PO4-P concentration was 6.07-6.37 mg l(-1). Total phosphorus (TP) and total nitrogen (TN) removal efficiencies were around 89.6% and 14.5-16.1%, over 3.5 and 1 times higher than those of control, respectively. COD removal rate in the lime-addition reactor was 2.05-2.48 kg COD m(-3) d(-1), higher than 1.34-1.61 kg COD m(-3) d(-1) in the control.
Wu
X L
XL
Department of Environmental Engineering, Tsinghua University, Beijing, China.
Guan
Y T
YT
Zhang
X
X
Huang
X
X
Qian
Y
Y
D000397:Air Pollution / Q000517:prevention & control; D019149:Bioreactors; D017610:Calcium Compounds / Q000737:chemistry; D005740:Gases; D009609:Nitrous Oxide / Q000032:analysis*; D010087:Oxides / Q000737:chemistry; D010758:Phosphorus / Q000378:metabolism*; D012722:Sewage / Q000737:chemistry* / Q000382:microbiology; D014865:Waste Disposal, Fluid; D018508:Water Purification / Q000379:methods*
D017610:Calcium Compounds; D005740:Gases; D010087:Oxides; D012722:Sewage; D010758:Phosphorus; C016538:lime; D009609:Nitrous Oxide