Plume boundaries

One simplified method for determining stack height is a geometric method described in ASHRAE. The geometric method assumes an exhaust plume shape with a lower boundary having a 1 5 slope relative to the horizontal. The stack and plume are raised until the lower plume boundary is above rooftop penthouses, separation zones, and zones of high turbulence. ASHRAE provides equations for the sizes and locations of the separation and turbulence zones. A stack height reduction credit is provided to account for the vertical exhaust momentum. 

A tank has ruptured and a pool of benzene has formed. The pool is approximately rectangular with dimensions of 20 ft by 30 ft. Estimate the evaporation rate and the distance affected downwind. Define the plume boundary using the TLV-TWA of 10 ppm. It is an overcast day with a 9 mph wind. The temperature is 90°F. 

HANNA, S.R. The exponential probability density function and concentration fluctuations in smoke plumes, Boundary Layer Met., 29, 361-375, 1984. 

The two contaminant plumes are represented in the first stage of the optimization formulation with a set of 110 control points along the plume boundaries. These same control point locations are used as starting points for particles when forward tracking is used in the second stage of the solution process. For the unconfined simulation, additional constraints are included to require a minimum saturated thickness of 1.5 m at each well cell. Both confined and unconfined assumptions are simulated under two sets of penalty parameters. Recall that the solution algorithm uses the penalty method for the plume capture constraints, in which each constraint violation is multiplied by a penalty parameter and added to the objective function. 

Figure 9. Map of field site at Picatinny Arsenal, NJ showing the location of 10 g/L trichloroethene (TCE) plume boundary, subsurface air pressure and moisture content sampling site, and withdrawal wells for the pump-and-treat remediation system.

To describe a zone of potential effect, information about the initial concentration of the effluent, its dilution in the receiving water, and the extent of the 1% plume is required. Some pulp mills calculate a range of concentrations from the outfall to the 1% effluent plume boundary. Tracer studies and additional conductivity measurements taken during field work can support previous plume delineation studies to identify the areas in the receiving waters having effluent concentrations greater than 1 %. The zone of potential effect for a sublethal test result can then be mapped onto the 1 % effluent plume based on where the effluent concentrations are... 

Xu Y.- G., Menzies M. A., Bodinier J.-L., Bedini R.-M., Vroon P., and Mercier J.-C. (1998) Melt percolation-reaction at the lithosphere-plume boundary evidence from the poikiloblas-tic peridotite xenolith from Boree (Massif Central, Frace). Contrib. Mineral. Petrol. 132, 65-84. 

The sulfur compounds involved in the sulfate-reduction process are of interest, but the prevalence of sulfate reduction in leachate plumes is not very well understood (Murray et al., 1981). Nitrate and perhaps sulfate as well may be depleted in the core of the plume, but they are certainly significant players at plume boundaries. 

Figure 2.16 Distorted plume caused by canyon winds and diffusion from an elevated source. Plume boundaries (defined a fixed ratio, e.g. 1/10 of centerline concentration at given value of x) in horizontal plane, showing components unentrained (dash-dot line), detrained (dashed line) and plume in canyon below building height (shading).

FIGURE 18.2 Plume boundaries and concentration distributions of a plume at different averaging times. 

Second, perception of the plume boundary, i.e. a marked decrease in odor concentration, releases a turn to the opposite tack (counterturn), keeping a walking insect within a plume (Fig. 4.4) B. mori - Kramer, 1975 P. americana - Tobin, 1981). These results show that olfactory information processing is involved to a certain extent in regulating orientation within an odor plume. Since cockroaches with only one antenna turn into the plume when they reach a boundary, we can assume that temporal comparisons are employed, at least by... 

Slick Rock (NC), CO UMTRA(Titlel) 0.24 0.12 20-50 Sampling restricted to tailings pile. Plume may be bigger than estimated. Monitoring wells at plume boundary show [U] 900-1000 ppb. 

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