• Karolina Furgal
Organic micro-pollutants (e.g., fragrances, bactericides, pharmaceuticals, and flame retardants) can be detected in surface waters, outlet from the WWTPs and sludges [3-6], which proves the ineffectiveness of existing water purification technologies in removal of these compounds. The compounds are frequently used in personal care products, plastic and textiles applications. Some have been classified as a priority pollutant, suspected to have mutagenic, carcinogenic or toxic effects [1, 2]. Sorption to the sludge is often the major removal mechanism for the organic micro-pollutants from the WWTPs, due to the high octanol-water partition coefficient Kow. The presence of the organic micro-pollutants in the sludge has recently been target of growing interest regarding the safe disposal of the sludge. The focus of this study was to investigate the enhanced biodegradation of organic micro-pollutants in the digested sludge under aerobic, anoxic and anaerobic conditions. For this reason, lab-scale sludge reactors were employed. Additionally an aerobic treatment of the digested sludge from Ejby Mølle WWTP was investigated in order to remove organic micro-pollutants, decrease the amount of the sludge and hence save money for the disposal. For these purposes the compounds were extracted from the sludge by liquid-liquid extraction (LLE), condensed in toluene to 1 mL and quantified by use of gas chromatography - mass spectrometry (GC–MS). The most rapid elimination for most of the examined organic micro-pollutants in activated sludge was observed under the presence of oxygen. The highest removal rates were observed for the light PAHs, OTNE, TnBP and DEHP, intermediate removal rates for triclosan, HHCB and some of the heavy PAHs, while low or no removal was observed for AHTN, nonylphenols and transformation products HHCB-lactone and triclosan-methyl in activated and digested sludge. Moreover, a test on a possible performance of an existing tank at Ejby Mølle WWTP was made. The calculations showed that after the available retention time during the aerobic treatment in the existing tank all the compounds’ concentrations would be below the limit except the concentration of nonylphenol isomers, which is far above the Danish cut-off value.
Antal sider74
Udgivende institutionAalborg University
ID: 17728321