Case Studies
Natural Attenuation Assessment
at Plattsburgh Air Force Base,
New York
Shu-Chi Chang, Ph.D., P.E., P.A.
Assistant Professor1 and Division Chief2
1Department of Environmental Engineering
2Division of Occupational Safety and Health,
Center for Environmental Protection and Occupational Safety and Health
National Chung Hsing University
Wednesday, June 06, 2007
Outline



Bioavailability
Case study 1
Case Study 2
Homework assignment will be on line tonight.
Bioavailability

Assumptions and considerations




Microbes are excluded from the smaller
microspores of soil and porous media
Intrapore diffusion may be retarded due to
sorption
Only dissolved fraction is available
Aging
Bioavailability
Max flux at part. surface
Max diffusive rate
>1
<1
Max Biokinetic rate
Max diffusive rate
>1
Pore sorption /
diffusion control
Max Biokinetic rate
Flux at particle surface
<1
Biokinetic
control
>1
Bulk phase
transport control
Ramswani A. and Luthy R., 1997, Measuring and modeling physicochemical limitations to bioavailability and biodegradation. In Manual of
Environmental Microbiology, Christon et al (Editors) ASM Press, Washington DC, USA.
Site description
Plattsburgh AFB, New York
Electron donors, electron
acceptors, by-products
Biodegradation rate and
transferred electron equivalents
Bird-Eye-View of the Site
Source
Bioavailability estimation
Source lifetime
Source Lifetime Estimation

Assumption
1.
1000
Lifetime (Year)
2.
3.
BTEX
100
BTEX
TCE
10
TCE
1

Results
1.
2.
1
2
3
4
5
6
Methods
3.
Methods:
1. Tracer methods w/o EBC
2. Tracer methods w/ EBC
3. B&A methods w/o EBC
4. B&A methods w/ EBC
5. Newell Method w/o EBC
6. Newell Method w/ EBC
Source pool dim.: 900ftx315ftx1.5ft
foc=0.001, ρb= 1.7g/cm3
25% electron transferred to TCE
and DCE
4.
Tracer methods yield the longest
lifetime, while Newell the shortest.
Order of mag. diff. for BTEX and
TCE, two orders of mag diff. for
DCE
DCE may be a long term problem
in source zone since it is easily
degraded under anaerobic
conditions.
No dramatic diff. in source lifetime
with or without the consideration of
EBCs in source zone.
Trend observation
Long term monitoring protocol


Purpose
Monitoring plan


Community involvement
Institutional control and long term
monitoring




Well installation
Sampling and analysis plan
Monitoring period
Contingency plan