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EPA On-line Tools for Site Assessment Calculation


Transport and Leaching from a Release of Fresh Fuel

One Dimensional Transport Equation

This calculator generates a breakthrough curve* at a receptor and uses a one-dimensional model to determine the

  1. First arrival time for a contaminant (above a specified threshold concentration),
  2. Maximum Concentration, and
  3. Duration of Contaminantion above the specified threshold

*The breakthrough curve is the time history of concentration at a receptor located a specified distance from the contaminant source.

Example breakthrough curve.

See bottom of page for equations solved.>


 

Inputs


Date








mg/L

mg/L



Water Saturation















Gradient (absolute value) (−i)









Default Parameters





Percent Mass Fraction
Intermediate Results













Beginning Time of Breakthrough Curve
Breakthrough Curve Through Maximum Concentration




Completion of Breakthrough Curve (for Pulse Sources)






Advective Travel Time




One Dimensional Transport Equation

One-dimensional transport equation

R = retardation factor []
D = dispersion constant [L2/T]
v = seepage velocity [L/T]
μ = first order decay constant [1/T]


with the initial and boundary conditions

Boundary conditions
retardation factor R = 1 + ρ b k d

R = retardation factor
ρ b = bulk density = ρ s (1-θ)
ρ s = solids density
θ = porosity
k d = (soil) distribution coefficient = f o c K o c
f o c = fraction organic carbon
K o c = organic carbon/water partition coefficient

travel time t t r = x R / q s

t t r = advective travel time*
q s = seepage velocity
R = retardation factor
x = distance
* assuming one-dimensional, steady flow, constant gradient

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