Characteristics of the bioreactor landfill system using an anaerobic-aerobic process for nitrogen removal.
A sequential upflow anaerobic sludge blanket (UASB) and air-lift loop sludge blanket (ALSB) treatment was introduced into leachate recirculation to remove organic matter and ammonia from leachate in a lab-scale bioreactor landfill. The results showed that the sequential anaerobic-aerobic process might remove above 90% of COD and near to 100% of NH4+ -N from leachate under the optimum organic loading rate (OLR). The total COD removal efficiency was over 98% as the OLR increased to 6.8-7.7 g/l d, but the effluent COD concentration increased to 2.9-4.8 g/l in the UASB reactor, which inhibited the activity of nitrifying bacteria in the subsequent ALSB reactor. The NO3- -N concentration in recycled leachate reached 270 mg/l after treatment by the sequential anaerobic-aerobic process, but the landfill reactor could efficiently denitrify the nitrate. After 56 days operation, the leachate TN and NH4+ -N concentrations decreased to less than 200 mg/l in the bioreactor landfill system. The COD concentration was about 200 mg/l with less than 8 mg/l BOD in recycled leachate at the late stage. In addition, it was found that nitrate in recycled leachate had a negative effect on waste decomposition.
He
Ruo
R
Ministry of Education Key Lab of Environment Remediation and Ecological Health, Zhejiang University, Hangzhou 310029, China. heruo@zju.edu.cn
Liu
Xin-Wen
XW
Zhang
Zhi-Jian
ZJ
Shen
Dong-Sheng
DS
D000332:Aerobiosis; D000693:Anaerobiosis; D019149:Bioreactors; D052918:Environmental Restoration and Remediation / Q000379:methods*; D009584:Nitrogen / Q000302:isolation & purification; D012037:Refuse Disposal
D009584:Nitrogen