HR: 16:30h
AN: A54B-05    [Abstracts]
TI: Measurement and Experimental Validation of N2O Formation and Emission in Domestic Wastewater
AU: * Vergara, W
EM: wvergara@worldbank.org
AF: The World bank, Environment Department, 1850 I Street N.W., Washington, DC 20433 United States
AU: Meneses, A
EM:
AF: Universidad de Pamplona, Km. 1 V¡a Bucaramanga, Pamplona, Colombia
AU: Deeb, A
EM:
AF: The World bank, Environment Department, 1850 I Street N.W., Washington, DC 20433 United States
AU: Suarez, C
EM:
AF: Corporacion Defensa de la Meseta de Bucaramanga, Carrera 23 No 37 - 63 , Bucaramanga, Colombia
AB: Ammonium nitrogen, in the form of highly soluble ion (NH4+), is one of the characteristic contaminants of industrial effluents, of untreated municipal discharges and of anaerobic and/or facultative municipal WWTPs effluents, where there is no removal of NH4+. In this case, N2O formation and emission may end up being more severe than in advanced treatment systems, although this occurs outside of the installation's physical boundaries, i.e., when the nitrogen-rich discharge is returned to a receiving body of water where natural and non-selective N/D processes are stimulated. There is however, great uncertainty on the quantification of N2O emissions from surface waters, because most studies of N2O formation have been carried out in groundwater, mouths of rivers, inland seas, and stagnant waters, which often have more favorable conditions for N2O formation: restricted availability of oxygen, greater presence of nitrifying micro-organisms, and high levels of alkalinity. Furthermore, the high solubility of N2O in water favors high concentrations of this gas in infiltrated and ground water and thus tends to remain in liquid phase until it finds the right conditions for its release into the atmosphere (Bowden & Bormann, 1986; Yoshinari et al, 1997; Bateman & Hiscock, 2001). Recently, thanks to the notable evolution of the isotopic monitoring of contaminants, and laser spectroscopy it has been possible to identify several preferential paths in the biochemical transformation of nitrogen and its derivatives in situ. Everything seems to indicate that the non-selective nitrification of the ammonium ion is the principal path of N2O formation in water systems (Ueda et al, 1993; Kim & Craig, 1993; Bateman & Hiscock, 2001). As part of the proposed Rio Frio Wastewater Treatment and Carbon Offset Project, nitrogen in the effluent will be removed through a combination of aoxic and anoxic treatment steps. Measurements have been designed to determine the background emissions of N2O in the rivershed receiving the effluent of the plant as well as at the plant site, before and afetr construction of a nitrogen removal scheme at the plant. The measurements constitute a first of a kind combination of laser spectroscopy, gas chromatography and mass spectrometry to measure N2O in river-shed wide area, at an accuracy required to document emission reductions of N2O. The measurements will also contribute to a better understanding of the mechanism of formation of N2O and to the determination of N2O emission factors. This paper describes the measurement systems designed for the purpose and the monitoring protocols that would be used to document the baseline and emission reductions of N2O. The results are expected to influence climate policy as it relates to N2O emissions from wastewater treatment plants.
DE: 0317 Chemical kinetic and photochemical properties
DE: 0322 Constituent sources and sinks
DE: 1610 Atmosphere (0315, 0325)
DE: 1620 Climate dynamics (3309)
SC: Atmospheric Sciences [A]
MN: 2005 Joint Assembly