Wozei, EleanorHermanowicz, SW2020-03-042021-12-212020-03-042021-12-212006-04-11E Wozei and SW Hermanowicz. Application of a yeast-based assay protocol developed to monitor total oestrogenic activity induced by 17β-oestradiol in activated sludge supernatants from batch experiments. Lawrence Berkeley National Laboratory, Mail Stop 70A-3317, 1 Cyclotron Road, Berkeley, CA, 94720. 11th April, 2006. ISSN 0378-4738 = Water SA Vol. 32 No. 3 July 2006 ISSN 1816-7950 = Water SA (on-line)https://hdl.handle.net/20.500.11951/873This is a research paper on Application of a yeast-based assay protocol developed to monitor total oestrogenic activity induced by 17β-oestradiol in activated sludge supernatants from batch experimentsBatch experiments were carried out with activated sludge from laboratory reactors and a full-scale treatment plant spiked with 17β-oestradiol (E2). An oestrogen-sensitive yeast-based assay protocol, described in detail in a related publication, was used to measure reduction of E2-induced total oestrogenic activity from the sludge supernatant over a 15 d period after which the sludge was re-spiked to check for possible enhancement of reduction by pre-exposed sludge during an additional 15 d period. The reduction was generally improved by increasing sludge solids concentrations and by continuous mixing. For a 100 ngE2/ℓ spike there was >40% reduction of oestrogenic activity within 15 d, which improved to >70% by pre-exposing the sludge. The oestrogenic activity produced by a dose of 100 μgE2/ℓ was readily removed by most sludges within 15 d. How¬ever, re-spiking the activated sludge with the same E2 concentration caused some sludges to lose reduction capacity.enSludge17β-oestradiolOestrogen receptorSuspended solidsYeastArticle