Passive Secondary Biological Treatment Systems Reduce Estrogens in Dairy Shed Effluent

Abstract

Steroid estrogens are found at high concentrations in untreated dairy shed effluents. Reduction of estrogenic activity and steroid estrogen concentrations was assessed in two systems used to treat dairy shed effluents: the two-pond system and the advanced pond system. Both include anaerobic and aerobic treatment stages. Samples of effluent were collected from the systems and analyzed for free estrogens, conjugated estrogens and total estrogenic activity using E-Screen assay. Both systems showed increases of up to 8000% in aqueous free estrogens and estrogenic activity after anaerobic treatment, followed by decreases after aerobic treatment (36-83%). The complete systems decreased total steroid estrogen concentrations by 50-100% and estrogen activity by 62-100%, with little difference between systems. Removal rates were lower in winter for both systems. Final effluents from the advanced pond system contained total estrogens at <15-1400 ng/L and estrogenic activity at 3.2-43 ng/L. Final effluent from the two-pond system contained total estrogens at <15-300 ng/L and estrogenic activity at 3.3-25 ng/L. At times the final effluent EEQs exceeded guideline values for protection of freshwater fish and suggest further treatment may be required.

Genomic and phenotypic response of hornyhead turbot exposed to municipal wastewater effluents

“…The estradiol equivalent value (EEQ) in PL whole effluent was 20.3 ng/L (EEQ in HTP effluent = 11.2 ng/L). The PL EEQ value is similar to those of other municipal wastewater effluents (Gadd et al, 2010;Körner et al, 2001). EEQs values over 5 ng/L of E2 have been found to cause male vitellogenesis in fresh water species such as Japanese medaka (Oryzias latipes) (Bulloch et al, 2010;Kitamura et al, 2009).…”

Identification of a new steroid degrading bacterial strain H5 from the Baltic Sea and isolation of two estradiol inducible genes

“…A similar phenomenon was found in one STW in Italy [32]. In other words, biological treatment of wastewater, involving the action of steroid degrading bacteria, is required to remove estrogens and other steroids from wastewater [31]. As mentioned above, most of the steroids are excreted from animal and human sources in their conjugated form which requires deconjugation by enzymes like carboxylesterase to make the steroid nucleus available for bacterial degradation upon biological treatment of wastewater.…”

“…However, conjugated estrogens cannot be digested by bacteria directly, but must undergo a preceding deconjugation step first. Carboxylesterase is an enzyme catalyzing the deconjugation of a variety of estrogen-esters to form free estrogens which then could be degraded by bacteria [31]. Therefore, the gene coding for carboxylesterase which we isolated in our studies might be an important factor for steroid degradation in the marine bacterial strain H5.…”

Assessment of microbiological and biochemical properties of dairy sewage sludge

“…It is mainly related to the high water content with the sanitary hazard that it constitutes. Steroid estrogens were found at high concentrations in untreated dairy shed effluents (Gadd et al 2010). Also, the operating cost associated with the sludge handling is often reported to be a significant part of the overall operating cost in the wastewater treatment plant (Teh et al 2016).…”