PARENT SESSION

1B+C Abiotic Transformation
Hall 9
8:30 AM - 12:30 PM, Monday, 28 April 2003
Chair: Peijnenburg, W.¹, ¹
Co-chair: Jafvert, C.T.², Gombar, V.K.³, ^{2 3}

(MO9/2) Degradation of steroids in activated sludge.

Weber, Stefanie¹, Leuschner, Prisca¹, Dott, Wolfgang¹, Juliane, Hollender¹, ¹ Institute of Hygiene and Environmental Health, Pauwelsstr. 30, Aachen, Germany, Germany

ABSTRACT- Synthetical steroids such as 17--ethinyl estradiol often persist in the sewage treatment process and metabolites of the natural steroids such as estrone from estradiol accumulate resulting in relevant amounts in the aquatic environment. In order to study the biological processes in the sewage treatment plant the degradation of the natural hormone 17--estradiol (E2) and the synthetical hormone 17--ethinyl estradiol (EE2) was investigated. Batch experiments were performed with activated sludge from different sewage treatment plants with conventional and membrane technology. Analysis of the steroids was performed by HPLC with UV and fluorescence detection without further sample preparation with limit of quantification of 5 - 10 g/L. E2 was transformed in the experiments after 3 to 8 hours to estrone (E1), the main metabolite, and further completely degraded within 72 hours. EE2 was persistent in the most experiments. Further enrichment of the microorganisms led to a culture with three bacteria that are still able to transform E2, E1 and even estriol (E3). The transformation ratio of E2 by this enriched culture increased by decreasing concentrations. Xenoestrogenes such as mestranol, bisphenol A, a-zearalenol were not metabolized. Pure cultures were isolated and identified by physiological and biochemical tests as well as 16S rRNA and fatty acids analysis. The main bacteria was determined as Ochrobactrum anthropi.

Key words: estrogens, steroids, degradation, activated sludge