Estrogen biodegradation kinetics and estrogenic activity reduction for two biological wastewater treatment methods.
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.
Gaulke
Linda S
LS
Department of Civil and Environmental Engineering, University of Washington, Box 352700, Seattle, Washington 98195-2700, USA. lsg@u.washington.edu
Strand
Stuart E
SE
Kalhorn
Thomas F
TF
Stensel
H David
HD
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
D004967:Estrogens; D008567:Membranes, Artificial; D012722:Sewage; D004970:Estrone; D004958:Estradiol