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 PARENT SESSION
62 - Oil Pollution and Biodegradation
2:10 PM to 5:20 PM, Wednesday, 15 May 2002
Session Chair: Fritz, Johann 1, Nozhevnikova, Alla 2, Babel, Wolfgang 3, Loibner, Andreas Paul 4, 1 2 3 4 .
Stolz B
(62-01) Removal of Bisphenol-A, 17- -Estradiol and 17- -Ethinylestradiol during wastewater treatment. Degradation and adsorption to activated sludge.
Kreuzinger, Norbert*,1, Clara, Manfred1, Saracevic, Ernis1, Doell, Silvia1, 1 Institute for Water Quality and Waste Management, Vienna, Austria
ABSTRACT- Wastewater treatment plants showed to be a significant source for xenobiotic substances in surface waters. Among others, Bisphenol-A, 17--Estradiol and 17--Ethinylestradiol recently attained scientific as well as public interest. In order to evaluate and optimize the efficiency of wastewater treatment plants and to minimize effluent concentrations, basic knowledge on the behaviour of those substances during the different steps of wastewater treatment has to be derived. This paper deals with investigations on degradation and adsorption behaviour of Bisphenol-A, 17--Estradiol and 17--Ethinylestradiol during wastewater treatment, based on a low loaded activated sludge system. Lab-scale batch- and continuous flow experiments were conducted for determination of adsorption kinetics considering both, different pH values and different concentrations of adsorbate and adsorbent. Analysis of results derived from experiments with active and inactive (poisoned) sludge from wastewater treatment together with long-term continuous flow experiments give evidence on removal of these substances during wastewater treatment. Adsorption to activated sludge showed to be the main process for removal of the substances. The activated sludge from a municipal wastewater treatment plant used for experiments is able to adsorb all investigated substances up to mg/g for Bisphenol and several  g/g dry matter for hormones respectively being some orders of magnitude above monitored environmental concentrations. Adsorption behaviour and remaining dissolved substance concentration are described by Langmuir kinetic. The stability of the adsorption complex was tested for a pH-range between pH 5 and 13. All substances show significant desorption around pH 11, which is important for back load of treatment plants when applying lime for sludge treatment. Significant microbial degradation was observed for all substances investigated. Corresponding results were derived from batch and continuous flow experiments with a lab scale aerobic wastewater treatment plant fed with synthetic wastewater and addition of known concentrations of the investigated substances. A degradation rate up to 150 g/g dry matter was observed for Bisphenol-A and Estradiol, but is just half the value for Ethinylestradiol.
Key words: degradation, endocrine disruptors, wastewater treatment
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