organic substrate selection considerations for specific … · 2020-04-25 · the practical...
TRANSCRIPT
Organic Substrate Selection Considerations for Contaminant‐Specific Treatment Using
Bioinfiltration Systems
Paul A. Hagerty, P.E., Hagerty Environmental, LLCLinda A. Figueroa, Ph.D., P.E., Colorado School of Mines
Jim Fricke, Resource Management Consultants
PRESENTATION OVERVIEWPURPOSEShare research and experience on passive organic treatment systemsCommonality with bioinfiltration systems
Bioinfiltration (aka bioretention or rain gardens)• Biological treatment of stormwater using organic substrate
Passive Organic Treatment (aka biochem reactor)• Biological treatment of industrial and mining effluent and/or groundwater using organic substrates
PASSIVE ORGANIC vs BIORETENTION
Passive Organic Treatment System
Bioretention Cell / Rain Garden (courtesy PADEP)
ORGANIC SOURCES• Numerous substrate ingredients• Bioretention references specify “planting soil” “mulch” “compost” Infers that any organics will do
• Research and experience indicate that all organics are not created equal
WHAT DOES THE ORGANIC DO?
Biological treatment mediated by microorganisms (e.g., bacteria)
Microorganisms only need three things:1. Favorable Environment (aerobic/anaerobic)2. Energy Source (electron donor) ‐ carbon3. Nutrients (macro and micro)
Organic substrate provides e‐ donor and carbon (heterotrophic microorganisms)
CONTAMINANT‐SPECIFIC TREATMENT
Appropriate substrate selection requires an understanding of treatment processes
CONTAMINANT BIOLOGICAL PROCESS CONDITIONS
Petroleum Hydrocarbons
Aerobic Biodegradation Aerobic – Hydrocarbon is carbon source
Nitrate Denitrification (Facultative) Facultative ‐ Carbon
Heavy Metals (Pb, Cu, Zn)
Sulfate Reduction (Obligate Anaerobes)
Anaerobic – Carbon ‐Reducing Conditions
Chlorinated Solvents (TCE)
Reductive Dehalogenation Anaerobic – Carbon ‐Reducing Conditions
LONG‐TERM BIOAVAILABILITY HOW LONG WILL CARBON LAST?• Passive Organic Systems
– Originally thought 30+ years– Many systems are lasting 3‐10 years
• Are bioretention systems infinite??• Bioavailability Tests
– Select Substrate Ingredients– Predict Longevity of Substrate Mix– Identify If Substrate Is Spent
BIOAVAILABILITY – PLANT STRUCTUREPlant Mass Constituents
Biodegradability– Cellulose– Hemicellulose– Lignin
Lignin is the cementing agent and is the key to bioavailability
BIOAVAILABIILTY TESTINGLIGNIN CONTENT METHOD• 1967 (Van Soest) and 1980 (Chandler)• Predictive model between lignin content and biodegradability
ESF/WSF METHOD• Good Indicators ‐Water‐soluble fraction (WSF) and ethanol soluble fraction (ESF).• Poor Indicators ‐ Organic carbon and total organic content
(Figueroa, Seyler and Wildeman)
REGENERATION METHODS • Excavate and Replace• Liquid Carbon
– Slow Release: Edible Oil Substrate
– Soluble: Ethanol (Leviathan Mine)
• Zero Valent Iron (ZVI) –Anaerobic e‐ donor
• Alfalfa Pellets (Labile Carbon)• Stockpile and Wait (fungi)
GRAIN SIZE IMPACTSMETHOD – Plot grain size fractions vs SRR and % metals
removal, where: SRR – Sulfate Reduction Rate (mol SO4/m3‐day) % Removal of total and dissolved Zn and Pb
R² = 0.245
R² = 0.7325
R² = 0.2836
0.00
5.00
10.00
15.00
20.00
25.00
30.00
35.00
40.00
45.00
50.00
0 20 40 60 80 100 120
Percen
tage of P
article Size
Percent (%) Total Zinc Removal
Grain Size vs. %T Zn Removal
%T Zn vs C Sand
%T Zn vs M Sand
%T Zn vs F Sand
Linear (%T Zn vs C Sand)
Linear (%T Zn vs M Sand)
Linear (%T Zn vs F Sand)
GRAIN SIZE ‐ CONCLUSIONSHypothesis Plausible – Grain size can effect treatment efficiency
Optimized Substrate Mix• Large, stable grain size component (e.g., coarse gravel) for stability• Significant medium sand size component for total metals removal• Minimal quantity of fine sand size and “fines” (i.e., passing #200)
COARSE MATRIX
MEDIUM SAND SIZE MINIMAL “FINES”
GRAIN SIZE / PERMEABILITY
COARSE MATRIX
MEDIUM SAND SIZE MINIMAL “FINES”
1.00E‐04
1.00E‐03
1.00E‐02
1.00E‐01
1.00E+000 10000 20000 30000 40000 50000 60000 70000 80000
Hydraulic Con
ductivity
(cm/sec)
Biocell Surface Area (SF)
Biocell Sizing as a Fxn(K) (500 gpm: 6 ft depth)
Size by K
Zone of Inefficient MeS Capture
Zone of Permeability Control
Optimum Permeability Range
PASSIVE NITRATE TREATMENT Sources ‐ Fertilization, CAFO, septic systemsDenitrification ‐ Facultative ‐ organic carbon
POINTTM System for Septic System Nitrate Treatment
SUBSTRATE SELECTION ‐ HYPOTHESIS/RESEARCH1. Less carbon consumed – longer bed life2. Biomass accumulation – hydraulics3. Grain size not critical – larger is better
NITRATE TREATMENT TESTING
OTHER ORGANIC ISSUES• Color at Start‐up• Natural Acids
– Analytical Interference– Metal ComplexationInterference
• N2 and H2S– Hydraulic Restrictions– Nuisance Odors
• Metals Mobilization– As, Fe, Mn
WHAT’S THE RIGHT ORGANIC MIX?• Project‐ and Contaminant‐specific • Primary Selection Criteria
– Source Availability– Economics
• Secondary Selection Criteria and Misc Factors – Some labile carbon for start‐up (alfalfa/cotton)– Some long‐term carbon for longevity (wood chips)– Inoculum only if quick start‐up is desired– Manures can be good and bad– Hardwood vs soft wood (density hypothesis)– If softwood Careful of saps, phenolics, etc.– Composted or uncomposted– Consider grain size– Substrate should be free of contaminants
CONCLUSIONS / REFERENCES
REFERENCES• Cornell University. Cornell Composting Science and Engineering, (http://compost.css.cornell.edu/science.html),
1996• Figueroa, L., Seylor, J. and Wildman, T. Characterization of organic substrates used for anaerobic bioremediation
of mining impacted Waters, International Mine Water Association, 2004• Hagerty, P., Figueroa, L. and Fricke, J. The Effect of Substrate Particle Size on Sulfate Reduction Treatment
Efficiency of Mining Influenced Waters, Society of Mining, Metallurgy and Exploration (SME) Annual Meeting, Denver, CO, March 2011
• Hagerty, P. and Taylor, J. Nitrate Removal for On‐Lot Sewage Treatment Systems: The POINTTM System. White paper prepared in support of an innovative on‐lot sewage treatment system for nitrate‐sensitive groundwater conditions. December 2004
• Haug, R. The Practical Handbook of Compost Engineering, Lewis Publishers, Boca Raton, FL, 1993• Pennsylvania Department of Environmental Protection (PADEP). Pennsylvania Stormwater Best Management
Practices Manual, December 2006 • U.S. Air Force Center for Engineering and the Environment. Technical Protocol for Enhanced Anaerobic
Bioremediation Using Permeable Mulch Biowalls and Bioreactors, May 2008
CONCLUSIONS Information is available regarding organic substrates From a passive biological treatment standpoint, all organics are not created equal Substrate selection should be an integral component of passive biological treatment design