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