1 / 47

Contaminant Hydrogeology V

Contaminant Hydrogeology V. Гидрогеология Загрязнений и их Транспорт в Окружающей Среде. Yoram Eckstein, Ph.D. Fulbright Professor 2013/2014. Tomsk Polytechnic University Tomsk, Russian Federation Fall Semester 2013. Air-Water Gas Exchange of Chemicals. Thin-Film Model.

aletha
Download Presentation

Contaminant Hydrogeology V

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Contaminant Hydrogeology V Гидрогеология Загрязнений и их Транспорт в Окружающей Среде Yoram Eckstein, Ph.D. Fulbright Professor 2013/2014 Tomsk Polytechnic University Tomsk, Russian Federation Fall Semester 2013

  2. Air-Water Gas Exchange of Chemicals

  3. Thin-Film Model Water-side control J = -Dw(Cw – Ca/H)/Zw where Zwis the thickness of the water film if Ca = 0 J = -DwCw/ Zw= -kwCw

  4. Thin-Film Model Air-side control J = -(Da/Za) (CwH - Ca) or J = – (Da - H/Za) (Cw - Ca/H) where Zais the thickness of the air film

  5. Thin-Film Model for H ≈ 0.01

  6. Estimating gas exchange coefficient

  7. Estimating gas exchange coefficient In absence of a tracer with a known gas exchange coefficient models are constructed empirically for each gas, e.g. the four models for kO2 : Neglescu & Rojanski, 1969 Owens et al., 1964 Thackston & Krenkel, 1969 Bennet & Rathbun, 1972

  8. Estimating gas exchange coefficient Similarly, gas exchange coefficients for slowly flowing waters, lakes or estuaries are approximated empirically: for slowly flowing or stagnant waters: kw[cm/sec] ≈ 4·10-4 + (4·10-5·u2w10) or ka[cm/sec] ≈ 0.3 + (0.002·uw10)

  9. Using gas exchange coefficient The air-water flux density is proportional to the difference between a chemical concentration in water [Cw] and the corresponding equilibrium concentration [CwH]. Therefore:

  10. Thin-Film of Air Model Above a Slick of NAPL while Zais the thickness of the stagnant air film above the slick, the velocity of gas transfer (vaporization) is proportional to Da of that gas

  11. Thin-Film of Air Model Above a Slick of NAPL the velocity of gas transfer (vaporization) is also dependent on the size of the slick v = 0.029·uw10·L-0.11·Sc-0.67 where: uw10 wind velocity 10m above the slick [m/hr] L is the slick diameter [m] Sc is the Schmidt number

More Related