Treatment efficiency and stability of antibiotics in wastewater
LE3 .A278 2018
Master of Science
The presence of antibiotics and other pharmaceuticals in wastewater is a growing concern. In municipal sewage treatment plants (STPs), antibiotics are only partially eliminated and can therefore be discharged into the environment regardless of wastewater treatment, affecting ecological and potentially human health. Target antibiotics in this research included beta-lactams, macrolides, fluoroquinolones, and triclocarban. An analytical method using liquid chromatography–tandem mass spectrometry (LC/MS/MS) was developed for quantifying these antibiotics. The efficiencies of wastewater treatment technologies used in STPs were determined by analyzing antibiotics in wastewater influents and treated effluents. Various treatment technologies were studied, including primary treatment, modified secondary, aerated lagoon, facultative lagoon, sequencing batch reactor, rotating biological contactors, and oxidation ditch. Further, antibiotic stability was investigated for samples stored in three levels of media: ultra-purified water, treated effluent and wastewater. The experiment was carried out under different conditions: in different non-prefiltered or prefiltered with 0.1 μm filters media stored at fridge temperature and room temperature. It was determined that prefiltration of the samples did not markedly affect the stability of the target antibiotics. Temperature was found to have significant impact on the degradation of antibiotics. The half-lives of antibiotics were inversely related to the storage temperature. It was speculated that fluoroquinolones and macrolides have higher persistence suggested by the concentration asymptote creating favouring conditions for the growth of antibiotic resistant bacteria. The activation energies of antibiotic degradation were calculated. High values of activation energies were found, indicating the antibiotic reactivity was mainly affected by the reaction temperature.
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