Fate of oestrogenic compounds and identification of oestrogenicity in a wastewater treatment process

Abstract

Understanding of the fate of oestrogen and oestrogenic compounds is important in improving the removal efficiency for oestrogens in wastewater treatment plants (WWTPs). In this study an attempt was made to clarify the fate of oestrogen, oestrogen sulphates, and oestrogenic compounds (synthetic oestrogen, nonylphenol and its relatives) by an instrumental analysis, and the fate of oestrogenicity by an in vitro assay. The investigation was conducted in an activated sludge WWTP in winter and summer, focusing on identification of the primary substances that induce oestrogenicity. Wastewater samples were analysed by employing the silica-gel fractionation technique in conjunction with two-step column chromatography. The results revealed that, in winter, the WWTP efficiencies for the removal of nitrogen and oestrogens decreased and the oestrone level increased with the progress of the treatment. Oestrone and oestrogenic substances are likely to circulate between the aeration tank and the final sedimentation tank. In summer, however, these compounds were effectively removed in the WWTP. The results of the column chromatography coupled with the bioassay suggested that E1 and E2 are the predominant contributors to the oestrogenicity in the influent, return sludge and effluent of the WWTP. The measurement by the instrumental analysis supported these findings.

Treatment and Removal Strategies for Estrogens From Wastewater

“…During winter, higher effluent concentrations for both natural and synthetic estrogens have been observed [16,71,93,94]. The reduced amount of the slow growing specified bacteria responsible for EE2 removal due to washout in winter-periods has also been cited as a factor.…”

“…The reduced amount of the slow growing specified bacteria responsible for EE2 removal due to washout in winter-periods has also been cited as a factor. An illustration of the effects of temperature on the estrogen removals in a STW can be found in a recent study by Nakada et al [94]. A comprehensive mass balance study was carried out on a Japanese STW [94] With the available data so far no correlation between the temperature and the E2 removal in full-scale treatment plants has been found [28,72].…”

“…An illustration of the effects of temperature on the estrogen removals in a STW can be found in a recent study by Nakada et al [94]. A comprehensive mass balance study was carried out on a Japanese STW [94] With the available data so far no correlation between the temperature and the E2 removal in full-scale treatment plants has been found [28,72]. A regression analysis of the data for E2 removal versus temperature gave only a r 2 value of 0.031, indicating no correlation.…”

Transformation and fate of natural estrogens and their conjugates in wastewater treatment plants: Influence of operational parameters and removal pathways

“…Similarly, a strong correlation was established between increasing temperature and decreasing conjugate concentration in the aqueous phase of activated sludge (r 2 ¼ 0.994) (Gomes et al, 2009). Temperature can influence the activity of arylsulfatase and b-glucuronidase as well as the abundance of bacteria that contain these enzymes (Liu et al, 2015;Nakada et al, 2006), which in turn affects the deconjugation of C-NEs. Table 1 shows that HRT and SRT had little correlation with the removal of C-NEs (p > 0.05), which indirectly supports that enzyme hydrolysis was a major removal pathway of C-NEs.…”

“…An important reason for the inconsistencies is that the operational parameters, including temperature, hydraulic retention time (HRT) and sludge retention time (SRT), varied greatly among the different studies. However, studies that discussed the influence of operational parameters on the NE removal also showed significant discrepancies (Clara et al, 2005;Hashimoto et al, 2007;Liu et al, 2015;Nakada et al, 2006). It is particularly difficult to isolate the influence of one operational parameter, as the treatment processes and other operational parameters differed across these studies.…”