title: Effect of microwave hydrolysis on transformation of steroidal hormones during anaerobic digestion of municipal sludge cake.
abstract: Fate and removal of 16 steroidal (estrogenic, androgenic and progestogenic) hormones were studied during advanced anaerobic digestion of sludge cake using microwave (MW) pretreatment. Effect of pretreatment temperature (80, 120, 160 °C), operating temperature (mesophilic at 35 ± 2 °C, thermophilic at 55 ± 2 °C) and sludge retention time (SRT: 20, 10, 5 days) were studied employing eight lab-scale semi-continuously fed digesters. To determine the potential effect of MW hydrolysis, hormones were quantified in total (sorbed + soluble) and supernatant (soluble) phases of the digester influent and effluent streams. Seven of 16 hormones were above the method reporting limit (RL) in one or more of the samples. Hormone concentrations in total phase of un-pretreated (control) and pretreated digester feeds ranged in <157-2491 ng/L and <157-749 ng/L, respectively. The three studied factors were found to be statistically significant (95% confidence level) in removal of one or more hormones from soluble and/or total phase. MW hydrolysis of the influent resulted in both release (from sludge matrix) and attenuation of hormones in the soluble phase. Accumulation of estrone (E1) as well as progesterone (Pr) and androstenedione (Ad) in most of the digesters indicated possible microbial transformations among the hormones. Compared to controls, all pretreated digesters had lower total hormone concentrations in their influent streams. At 20 days SRT, highest total removal (E1+E2+Ad +Pr) was observed for the thermophilic control digester (56%), followed by pretreated mesophilic digesters at 120 °C and 160 °C with around 48% efficiency. In terms of conventional performance parameters, relative (to control) improvements of MW pretreated digesters at a 5-d SRT ranged in 98-163% and 57-121%, for volatile solids removal and methane production, respectively.
authors.affiliation: School of Engineering, University of British Columbia, Okanagan Campus, 1137 Alumni Ave., Kelowna, BC V1V 1V7, Canada.
authors.forename: Hanna
authors.initials: H
authors.lastname: Hamid
authors.forename: Cigdem
authors.initials: C
authors.lastname: Eskicioglu
mesh_terms: D000693:Anaerobiosis; D000735:Androstenedione / Q000737:chemistry / Q000378:metabolism; D004970:Estrone / Q000378:metabolism; D006728:Hormones / Q000737:chemistry / Q000378:metabolism*; D006868:Hydrolysis; D008872:Microwaves; D011374:Progesterone / Q000378:metabolism; D012722:Sewage; D013256:Steroids / Q000737:chemistry / Q000378:metabolism*; D013696:Temperature; D013997:Time Factors; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000737:chemistry
chemical_list: D000735:Androstenedione; D004970:Estrone; D006728:Hormones; D011374:Progesterone; D012722:Sewage; D013256:Steroids; D062065:Wastewater
keywords: 17α-Ethinylestradiol; 17β-Estradiol; Ad; An; Anaerobic digestion; Androgen; Biosolids; CAS; COD; E1; E2; E3; EDC; EE2; Estrogen; K(d); MW; Microwave hydrolysis; Ms; OLR; PS; Pr; RL; SDL; SRT; Steroidal hormones; TS; TVFA; TWAS; Tr; VS; WAS; WWTP; androstenedione; androsterone; chemical abstract services; chemical oxygen demand; endocrine disrupting compound; estriol; estrone; mestranol; microwave; organic volumetric loading rate; partition coefficient; primary sludge; progesterone; reporting limit; sample specific detection limit; solid retention time; testosterone; thickened waste activated sludge; total solids; total volatile fatty acids; volatile solids; waste activated sludge; wastewater treatment plant