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Predicted vs measured air emissions of volatile organics from a simulated hazardous liquid waste lagoon.
Toxic and Hazardous Wastes: Proceedings of the Eighteenth Mid-Atlantic Industrial Waste Conference, June 29-July 1, 1986, Blacksburg, Virginia. Boardman GE, ed., Lancaster, PA: Technomic Publishing Company, Inc., 1986 Jun; :515-525
The evaporation of toluene (108883) and chlorobenzene (108907) from aqueous solution were measured under natural environmental conditions, and the observed emission rates and air concentrations were compared with those calculated from representative theoretical models. Solutions of toluene and chlorobenzene were stirred into a pool, 1.83 meters in diameter and 0.18 meters deep, on the roof of a five story building in an urban area. Air and pond concentrations and environmental conditions were measured during eleven 24 hour intervals over the following 2 months. Observed emission rates, determined by measuring the change in liquid concentrations over time, and the gas phase concentrations and wind speeds above the pool were compared with predicted emission rates calculated using the two resistance theory of mass transfer and a theoretically determined mass transfer coefficient. A mass balance on the pool indicated that approximately 90 percent of both the chemicals were lost through surface evaporation and liquid globules settling to the bottom within the first 30 minutes after being stirred into the pool. All estimates of the mass transfer coefficient reasonably predicted observed losses of toluene which occurred after the first 7 hours. However, observed losses of chlorobenzene did not correlate with predicted values due to the formation of globules on the bottom of the pond, which initially removed chlorobenzene from the solution and acted as a source of chlorobenzene after equilibrium was achieved. The authors conclude that the theoretical models discussed provide reasonable estimates of emissions of volatile chemicals from aqueous solutions over long time intervals, but a more complex model is necessary to take into account the early high evaporation rates and globule formation.
NIOSH-Grant; Chlorinated-benzenes; Volatiles; Air-contamination; Hydrocarbons; Toluenes; Waste-disposal; Toxic-vapors; Environmental-contamination
Toxic and Hazardous Wastes: Proceedings of the Eighteenth Mid-Atlantic Industrial Waste Conference
Occupational and Environ Med University of Illinois 2035 W Taylor Street Chicago, Ill 60612
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division