A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Estrogen Nitration Kinetics and Implications for Wastewater Treatment
Understanding estrogen‐removal mechanisms in wastewater treatment is imperative, as estrogens have environmental effects at trace concentrations. Previous research investigating co‐metabolic degradation of 17α‐ethinylestradiol (EE2) by ammonia‐oxidizing bacteria (AOB) revealed that, in batch tests where high nitrite‐nitrogen (NO2‐N) concentrations occurred as a result of ammonia‐nitrogen (NH4‐N) oxidation by AOB, an abiotic estrogen nitration reaction actually was occurring—not co‐metabolic degradation. This paper addresses nitration kinetics. A first‐order abiotic nitration model was developed that predicts nitration of EE2, 17β‐estradiol (E2), and estrone (E1) as a function of temperature, pH, estrogen (EE2, E2, and E1), and NO2‐N concentration. A contact time of 3.6 to 4.1 days is required for 90% estrogen nitration at 500 mg/L NO2‐N and pH 6.4. At 20°C and pH 6.4, the threshold NO2‐N concentration for nitration to occur is 9 mg/L; therefore, estrogen nitration is not likely in activated sludge treatment of domestic wastewater, but has potential for high‐NH4‐N‐strength wastewaters.
Estrogen Nitration Kinetics and Implications for Wastewater Treatment
Understanding estrogen‐removal mechanisms in wastewater treatment is imperative, as estrogens have environmental effects at trace concentrations. Previous research investigating co‐metabolic degradation of 17α‐ethinylestradiol (EE2) by ammonia‐oxidizing bacteria (AOB) revealed that, in batch tests where high nitrite‐nitrogen (NO2‐N) concentrations occurred as a result of ammonia‐nitrogen (NH4‐N) oxidation by AOB, an abiotic estrogen nitration reaction actually was occurring—not co‐metabolic degradation. This paper addresses nitration kinetics. A first‐order abiotic nitration model was developed that predicts nitration of EE2, 17β‐estradiol (E2), and estrone (E1) as a function of temperature, pH, estrogen (EE2, E2, and E1), and NO2‐N concentration. A contact time of 3.6 to 4.1 days is required for 90% estrogen nitration at 500 mg/L NO2‐N and pH 6.4. At 20°C and pH 6.4, the threshold NO2‐N concentration for nitration to occur is 9 mg/L; therefore, estrogen nitration is not likely in activated sludge treatment of domestic wastewater, but has potential for high‐NH4‐N‐strength wastewaters.
Estrogen Nitration Kinetics and Implications for Wastewater Treatment
Gaulke, Linda S. (author) / Strand, Stuart E. (author) / Kalhorn, Thomas F. (author) / Stensel, H David (author)
Water Environment Research ; 81 ; 772-778
2009-08-01
7 pages
Article (Journal)
Electronic Resource
English
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