Laboratory Evaluations to Support the Design of Biofiltration Systems in the Southwestern U.S. Robert Pitt, Ph.D., P.E., D.WRE, BCEE, University of Alabama Shirley Clark, Ph.D., P.E., D.WRE, Penn State - Harrisburg Brandon Steets, P.E., GeoSyntec Consultants.
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Laboratory Evaluations to Support the Design of Biofiltration Systems in the Southwestern U.S.
Robert Pitt, Ph.D., P.E., D.WRE, BCEE, University of Alabama
Shirley Clark, Ph.D., P.E., D.WRE, Penn State - HarrisburgBrandon Steets, P.E., GeoSyntec Consultants
ASCE/EWRI Conference, May 16-20, 2010, Providence, RI
thallium, perchlorate, tritium, uranium, gross alpha, gross beta, radium, and strontium-90.
potassium, conductivity, oxidation-reduction potential, filtered aluminum, and filtered iron.
Tried potential maintenance options when the flow rate decreased to 5 m/d (effects of disturbing media vs. removing media from filter).
Media removal generally more effective, but must remove at least 4 – 6” because clogging solids are captured deep in the media (deeper than visible solids buildup).
Column Test Results: Pollutant Removal(paired sign test of influent vs. effluent)
Recommended biofiltration mixed media combination
Layered filter media combination currently in use
R = rhyolite; SMZ = surface modified zeolite; GAC = granular activated carbon; PM = peat moss; S = site sand; Z = site zeolite
T = removal for total form (unfiltered); F = removal for filtered form (passed through 0.45-µm membrane filter)
Media Performance Plots for Copper, Full-Depth Long-Term Column Tests
14 µg/L limit
Dioxin Control Observations
2.8 X 10-8 µg/L permit limit
These samples were less than the detection limit
Breakthrough Capacity Compared to Clogging Period
Green: will clog before breakthrough
Red: breakthrough before clogging
Cumulative Particulate Loading to Failure and Expected Years of Operation for Largest Sedimentation-Biofiltration Treatment Trains on Project Site
Minimal filtered metal removal observed for all media except peat when contact time <10 minutes.
The optimal contact times for filtered metals removal ranged from 10 to 1,000 minutes, depend-ing on the metal and the media type.
Influent test water
Surface modified zeolite
Varying Depth Column Test Results
Example Relationship between Media Depth and Contact Time