Comparison of the retention of selected PAHs from municipal landfill leachate by RO and UF processes

摘要

The aim of the conducted research was to compare the changes in the retention of polycy-clic aromatic hydrocarbons (PAHs) during membrane filtration (ultrafiltration-UF and reverse osmosis-RO). In the study, municipal landfill leachate was used. In the first stage of testing, leachates were filtrated on the sand bed (prefiltration). After prefiltration, they were directed to the membrane module for main filtration. The ultrafiltration process was carried out at the transmembrane pressure of 0.1-0.2 MPa. The membrane separation process was based on a capillary membrane type ZW-10. The transmembrane pressure of the reverse osmosis stood at 2 MPa and for this process one nylon membrane (ADF) was used. The prepared samples of the municipal landfill leachates were subjected to extraction with applying 2-propanol. Extracts were cleared on octadecyl C18 columns, and then concentrated in the nitrogen stream. High-performance liquid chromatography HPLC with fluorescence detection (model HPLC THERMO) was used for qualitative and quantitative analysis of PAHs. During the process, a decrease in the concentrations of most tested hydrocarbons was observed. The initial concentrations of PAHs in the municipal landfill leachates were in the range 17.5-30.4 mg / L. The efficiency of the removal of hydrocarbons grouped according to a number of rings was in the range of 48 (for naphthalene) to 73% (for 6-ring of PAHs) in ultrafiltration technique. However, the greater efficiency retention of PAHs was obtained for RO. The average value of the retention coefficient for RO was equal to 71% (for individual hydrocarbons were in the range of 19-100%).