Occurrence and removal of organic micropollutants in the treatment of landfill leachate by combined anaerobic-membrane bioreactor technology.
Organic micropollutants, with high toxicity and environmental concern, are present in the landfill leachate at much lower levels than total organic constituents (chemical oxygen demand (COD), biochemical oxygen demand (BOD), or total organic carbon (TOC)), and few has been known for their behaviors in different treatment processes. In this study, occurrence and removal of 17 organochlorine pesticides (OCPs), 16 polycyclic aromatic hydrocarbons (PAHs), and technical 4-nonylphenol (4-NP) in landfill leachate in a combined anaerobic-membrane bioreactor (MBR) were investigated. Chemical analyses were performed in leachates sampled from different treatment processes, using solid-phase extraction and gas chromatography with electron capture detector and mass spectrometry. Concentrations of OCPs, PAHs, and 4-NP in the raw leachate were detected within the range from ND (not detected) to 595.2 ng/L, which were as low as only 10(-7)-10(-5) percentage of TOC (at the concentration of 2,962 mg/L). The removal of 4-NP was mainly established in the MBR process, in agreement with removals of COD, BOD, and TOC. However, the removals of OCPs and PAHs were different, mainly achieved in the anaerobic process. High removal efficiencies of both total organic constituents and organic micropollutants could be achieved by the combined anaerobic-MBR technology. The removal efficiencies of total organic constituents were in the order of BOD (99%) > COD (89%) > TOC (87%), whereas the removal efficiencies of investigated organic micropollutants were as follows: OCPs (94%) > 4-NP (77%) > PAHs (59%).
Xu
Yiping
Y
State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. ypxu@rcees.ac.cn
Zhou
Yiqi
Y
Wang
Donghong
D
Chen
Shaohua
S
Liu
Junxin
J
Wang
Zijian
Z
D000693:Anaerobiosis; D001673:Biodegradation, Environmental; D019149:Bioreactors; D002849:Chromatography, Gas; D008567:Membranes, Artificial; D009930:Organic Chemicals / Q000032:analysis / Q000302:isolation & purification*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods*
D008567:Membranes, Artificial; D009930:Organic Chemicals; D014874:Water Pollutants, Chemical