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Gas-film coefficients for streams

Journal of Environmental Engineering

By:
and
DOI: 10.1061/(ASCE)0733-9372(1983)109:5(1111)

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Abstract

Equations for predicting the gas-film coefficient for the volatilization of organic solutes from streams are developed. The film coefficient is a function of windspeed and water temperature. The dependence of the coefficient on windspeed is determined from published information on the evaporation of water from a canal. The dependence of the coefficient on temperature is determined from laboratory studies on the evaporation of water. Procedures for adjusting the coefficients for different organic solutes are based on the molecular diffusion coefficient and the molecular weight. The molecular weight procedure is easiest to use because of the availability of molecular weights. However, the theoretical basis of the procedure is questionable. The diffusion coefficient procedure is supported by considerable data. Questions, however, remain regarding the exact dependence of the film coefficint on the diffusion coefficient. It is suggested that the diffusion coefficient procedure with a 0.68-power dependence be used when precise estimate of the gas-film coefficient are needed and that the molecular weight procedure be used when only approximate estimates are needed.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Gas-film coefficients for streams
Series title:
Journal of Environmental Engineering
DOI:
10.1061/(ASCE)0733-9372(1983)109:5(1111)
Volume
109
Issue:
5
Year Published:
1983
Language:
English
Publisher:
ASCE
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Environmental Engineering
First page:
1111
Last page:
1127