Case StudiesNatural 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 Engineering2Division of Occupational Safety and Health,
Center for Environmental Protection and Occupational Safety and HealthNational 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 t
o sorption Only dissolved fraction is available Aging
Bioavailability
Max flux at part. surfaceMax diffusive rate
Biokinetic control
Pore sorption / diffusion control
Max Biokinetic rateFlux at particle surface
Max Biokinetic rateMax diffusive rate
Bulk phase transport control
>1
>1 <1
<1
>1
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
Assumption1. Source pool dim.: 900ftx315ftx1.5ft
2. foc=0.001, ρb= 1.7g/cm3
3. 25% electron transferred to TCE and DCE
Results1. Tracer methods yield the longest lif
etime, while Newell the shortest.2. Order of mag. diff. for BTEX and T
CE, two orders of mag diff. for DCE3. DCE may be a long term problem i
n source zone since it is easily degraded under anaerobic conditions.
4. No dramatic diff. in source lifetime with or without the consideration of EBCs in source zone.
Methods:1. Tracer methods w/o EBC2. Tracer methods w/ EBC3. B&A methods w/o EBC4. B&A methods w/ EBC5. Newell Method w/o EBC6. Newell Method w/ EBC
Source Lifetime Estimation
1
10
100
1000
1 2 3 4 5 6
Methods
Life
time
(Yea
r) BTEX
BTEX
TCE
TCE
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