title: Estrogen biodegradation kinetics and estrogenic activity reduction for two biological wastewater treatment methods.
abstract: Estrogens from anthropogenic and livestock sources are a serious concern for aquatic ecosystems at concentrations less than 1 ng/L Fundamental process parameters to reduce estrogenic activity were investigated for two biotreatment methods: heterotrophic bacterial degradation in municipal activated sludge (AS) and a nitration process that is applicable to high NH4-N wastewaters. Batch tests with estrogen and nitro-estrogen compounds were conducted at nanogram per liter concentrations with mixed liquor from an AS wastewater treatment facility (WWTF) operating at a 3 day solids retention time (SRT) and a membrane bioreactor (MBR) WWTF operating at a 30-40 day SRT. The estrogenic activities of estrone (E1), 17beta-estradiol (E2), and 17alpha-ethinylestradiol (EE2) were reduced 80-97% following nitration. First-order biological degradation rate coefficients (kb) of the nitrated estrogens were 10-50% lower than the parent estrogen compounds. The kb values for EE2 in MBR and AS mixed liquors were similar, 1.67 and 1.63 L/gVSS-day respectively, indicating that the bacteria responsible for EE2 degradation were present at long and short SRTs. The kb values for E1 and E2 were 2 orders of magnitude greater than for EE2. EE2 degradation was 7.5 times faster in the presence of E1 and E2, and no effect was observed with other estrogen mixtures.
authors.affiliation: Department of Civil and Environmental Engineering, University of Washington, Box 352700, Seattle, Washington 98195-2700, USA. lsg@u.washington.edu
authors.forename: Linda S
authors.initials: LS
authors.lastname: Gaulke
authors.forename: Stuart E
authors.initials: SE
authors.lastname: Strand
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Kalhorn
authors.forename: H David
authors.initials: HD
authors.lastname: Stensel
mesh_terms: D001673:Biodegradation, Environmental; D019149:Bioreactors / Q000382:microbiology; D001711:Biotransformation; D016001:Confidence Intervals; D004958:Estradiol / Q000378:metabolism; D004967:Estrogens / Q000378:metabolism*; D004970:Estrone / Q000378:metabolism; D007700:Kinetics; D008567:Membranes, Artificial; D012722:Sewage / Q000382:microbiology; D014865:Waste Disposal, Fluid / Q000379:methods*; D018508:Water Purification / Q000379:methods*; D015003:Yeasts / Q000378:metabolism
chemical_list: D004967:Estrogens; D008567:Membranes, Artificial; D012722:Sewage; D004970:Estrone; D004958:Estradiol