BIOCHLOR
C.E. Aziz
C. J. Newell
A.P. Smith
Groundwater
Services, Inc.
A Screening Level
Natural Attenuation Model
and Database for Solvents
J.R. Gonzales
P.E. Haas
Air Force Center
for Environmental
Excellence
Y. Sun
T.P. Clement
Battelle Pacific
Northwest National
Laboratory
BIOCHLOR Model
Domenico Solution for
Groundwater Transport
Reductive Dechlorination/
Sequential First Order Rxns
Why Use BIOCHLOR?
Method for Estimating Plume Lengths
System to Organize Site Data
Tool to Help Understand Site Processes
Screening Tool for Applicability of NA
Supporting Line of Evidence for NA
BIOSCREEN vs. BIOCHLOR: Similarities
n Domenico Analytical Model
n Microsoft Excel Platform
n User-Friendly Interface
n Based on Site Database
n Free Over the Internet
BIOSCREEN vs. BIOCHLOR: Differences
BIOSCREEN
BIOCHLOR
n Petroleum Hydrocarbon
Sites – BTEX
n Solvent Sites
n Biodegradation:
n More Complex
Biodegradation:
- 1st Order Decay or
- Electron Acceptor
Limited
- Sequential Reactions
- Different Zones
BIOCHLOR: Key Processes
n Advection (1-D)
n Dispersion (3-D)
n Sorption
n Biodegradation:
-
Reductive dechlorination
-
Sequential reactions (parents to daughters)
-
Limited hydrolysis
n Different biodegradation zones
BIOCHLOR Model
Domenico Solution for
Groundwater Transport
Reductive Dechlorination/
Sequential First Order Rxns
Sequential Reactions
l2
l1
PCE
TCE
l3
DCE
l4
VC
Rate PCE =
– l 1 C PCE
Rate TCE =
l 1 y 1 C PCE – l 2 C TCE
ETH
Reactive Transport Equations
Rate PCE
=
d CPCE
dt
d CTCE
Rate TCE
Rate TCE
=
=
= L ( CPCE ) - l 1 CPCE
= L ( CPCE ) + l 1 y 1 CPCE - l 2 CTCE
dt
d CTCE
= L ( CPCE ) + l 2 y 2 CTCE - l 3 CDCE
dt
etc. ...
A-D Equation (1-D advection, 3-D dispersion)
L ( C 1) = – v
d C1
dx
+ Dx
d 2C1
dx
2
+ Dy
d 2 C1
dy
2
+ Dz
d 2C1
dz2
BIOCHLOR Model
Domenico Solution for
Groundwater Transport
Y. Sun / T.P. Clement
Transformation
Results in BIOCHLOR
1.0
0.8
0.6
TCE
DCE
0.4
0.2
VC
0
Distance from Source
BIOCHLOR Model: Other Features
Two Reaction Zones for Mixed Sites
Source
PCE
TCE
Zone 1
DCE
VC
ETH
Zone 1:
High Decay Rates
(Carbon Present)
PCE
TCE
Zone 2
Zone 2:
Low Decay Rates
(No Carbon)
DCE
VC
ETH
BIOCHLOR Model: Other Features
n Single Vertical
Plane Source
n Superimposed Sources
(Connor et al., 1995)
Source 1
Source 2
Source 3
BIOCHLOR Model: Summary
n Predicts Parent, Daughter Compound
Concentrations
n Provides Analytical Solution to
Transport Equations with
Sequential Reactions
n Simulates Two Biodegradation Zones
for Mixed Sites
Zone 1
Zone 2
BIOCHLOR Version 2.0
n Rate Constant Decision
Support System
n Source Decay Option
n Animation Feature
How To Get BIOCHLOR . . .
Version 1.0:
n Available on CD OR
n Download free
Currently:
www.gsi-net.com
Jan. 2000:
Version 2.0:
n Available:
Fall 2000
www.epa.gov/ada/models.html
( CsMOS Web Page )
BIOCHLOR Demonstration
Case Study: Cape Canaveral AS, Fire Training Area
Release: Solvents, degreasers, JP fuels (1965-1985)
Site Hydrogeology:
n Avg. Depth to Groundwater
5 ft BGS
n Hydraulic Conductivity
1.8 x 10-2 cm/sec
n Hydraulic Gradient
0.0012 ft/ft
n Typical Groundwater
Seepage Velocity
112 ft/yr
BIOCHLOR Interface – Input Parameters
BIOCHLOR Output
Individual Chlorinated Solvent Output
Array Output