The use of biocells or engineered wetland to treat landfill leachate. Ammonia, chlorides, BOD, COD, iron, metals, salts, pH

1. Applied Ecological
Services, Inc.
Sustainable Solutions for Over 30 Years

2. Treatment Biocells for
Contaminant Removal from
Landfill Leachate
March 13, 2012
Doug Eppich, Ph.D., P.E.
John Roll, Ph.D., P.E.

3. Doug Eppich, Brian Tippetts, & John Roll

4. AES’ Landfill Overview:
•Nearly thirty years of serving the natural resources
industry
• Worked on a multitude of landfills with partners in
USA and Canada
• Expansions, closures and buffer land ecological
restoration (design-build )
• Beneficial re-use planning (parks, conservation, etc.)

5. AES’ Landfill Overview:
•Nearly thirty years of serving the natural resources
industry
• Worked on a multitude of landfills with partners in
USA and Canada
• Expansions, closures and buffer land ecological
restoration (design-build )
• Beneficial re-use planning (parks, conservation, etc.)

6. AES’ Landfill Solutions:
• Challenging permits with environmental issues
(Threatened and Endangered species, surface
water, neighbor/host agreement, wetlands and other
ecosystems)
• Beneficial re-use of landfills for conservation
• Legal discovery and support
• Closure and buffer restoration, plantings and stabilization
(design-build)
• Conservation storm water management and water quality
• Environmental group negotiation

7. Leachate Problems:
• N, BOD/COD, salts, metals
• Public Treatment Works (POTW) limitations
• Trucking costs
• Active landfill concentrations
• Regulatory acceptance, treatment “biocells”
• 30-year post closure

8. Landfill Leachate Constituents
Constituent Typical Ranges1 WQ Standards
- ***
2 mg/L *
0.050 – 0.340 mg/L ***
1 mg/L ***
1 – 10 µg/L *,***
- *
5 µg/L ***
250 mg/L **
0.050 mg/L ***
0.00001 - 0.2 µg/L **
0.0000006 – 0.24 µg/L **
0.300 mg/L *
50 µg/L ***
0.300 mg/L ***
* Biocell Treatment
** Not Treated in Biocells
*** Special Requirement (Ammend, Bacterial Inoculation, etc.)
1. Constructed Wetlands for Wastewater Treatment. Pgs. 735-742. Lewis Publishers, Inc. 1989.

9. Landfill Leachate Constituents
Constituent Typical Ranges1 WQ Standards
6.5 – 8.5 ***
1 - 5 µg/L *,***
- *
4.6 – 10 µg/L ***
- *,***
5 – 6,000 µg/L *,***
- *
0.002 µg/L *,***
* Biocell Treatment
** Not Treated in Biocells
*** Special Requirement (Ammend, Bacterial Inoculation, etc.)
1. Constructed Wetlands for Wastewater Treatment. Pgs. 735-742. Lewis Publishers, Inc. 1989.

10. Treatment Biocell Benefits:
• Cost reduction through reduced O & M
• Reduced waste disposal costs
• Added open space, green space, and wildlife elements
• Enhanced aesthetic appeal
• Minimal maintenance required
• Enhanced community relations through favorable land use
policy
• Compliance with federal, state, and local regulations regarding
storm water runoff and NPS pollution
• Elimination of environmentally damaging contaminants from
point and non-point sources

11. Treatment Biocell Data:
• Pre-design leachate water quality data is essential
• Evaluate outflow concentrations of the contaminants
• Size treatment biocells
• Determine if treatment biocells are feasible and warranted

12. Treatment Biocell Types:
• Free water surface (FWS) – Similar to natural biocells with open water and
vegetation. Usually a combination of interconnected aerobic (shallow water) and
aneorbic (deep water) cells.
• Horizontal subsurface flow (HSSF) – Typically a gravel bed with biocell planted on
the surface. Wastewater flows horizontally through the bed from inlet to outlet. The
root zone layer is usually aerobic trending rapidly to anaerobic conditions in the
saturated media bed.
• Vertical flow (VF) – Wastewater is distributed over a bed of sand, gravel, or other
porous media planted with emergent vegetation. Varies from aerobic to anaerobic
conditions at the bottom.

13. Biocell Treatment Processes:
• Physical -- Physical processes include sorption and
sedimentation.
• Chemical – Chemical processes include
precipitation, volatilization , photodegradation and constituent
conversion
• Biochemical – Many chemical processes in biocells are
mediated by specific bacteria such as the breaking of benzene
rings and denitrification. The effectiveness of the treatment
process depends on providing the proper environment
(temperature, pH, nutrients) for these bacteria to function.
• Biological– Biocell plants can provide important functions
including oxygenation of soils, vascular contaminant
storage, biofilm attachment surfaces and organic matter source

14. Biocell Physical
Treatment Processes
• Sedimentation (or settling) is the major removal pathway for
particulate pollutants. Sheetflow conditions promote
settling, and plant root stabilizes sediments, thereby reducing the
potential for re-suspension.
• Sorption The second primary removal pathway is by adsorption
of pollutants to surfaces of sediments, biocell vegetation, and
organic detritus.

15. Biocell Chemical
Treatment Processes
• Volatilization – Different processes in the biocell create gaseous
products that are released to the atmosphere. Volatile organic
compounds also diffuse to the atmosphere from biocells.
• Photodegradation – Sunlight on biocells can degrade chemicals
by direct photolysis or photooxidation.
• Chemical Reactions – Addition of chemical amendments to
biocells can be used to promote chemical reactions to convert
toxic materials to non-toxic or to cause toxic materials to
precipitate and be held in the bottom sediments.

16. Biocell Biochemical
Treatment Processes
• Biochemical Activity – Constructed biofiltration biocells
provide favorable conditions for active microbial growth.
Bacteria consume carbon and nitrogen compounds in the water
column and sediments. Wetlands breakdown chemical species in
sequential reaction steps that can remove complex contaminants
(e.g. reductive dechlorination of chlorinated organic compounds)
using specific bacteria to mediate the reactions.

17. Biocell Biological
Treatment Processes
• Uptake By Plants & Algae - Pollutant uptake by plants and
algae in vacuole storage removes nutrients and metals from the
water column and sediments. This plant material must be
harvested to effect a lasting removal.
• Accretion – Creation of new soil and sediment by stable
biomass that is resistant to decay and has its own chemical
composition.
• Plant Support Role – Plant roots, leaves and stems provide a
biofilm attachment location, the transport mechanism for
oxygenating soils and organic matter.

18. • Treated Leachate Constituents – Organic Nitrogen,
Ammonia, Nitrite/Nitrate
• Processes
- Ammonification
- Nitrification
- Denitrification
- Macrophyte growth
• Conditions – Aerobic and anaerobic zones, shallow & deep
pool biocells, carbon source needed

19. • Treated Leachate Constituents – Organic
Phosphorus, Inorganic Phosphorus
• Processes
- Macrophyte and microbiota growth
- Sorption
- Precipitation and Sedimentation
• Conditions – Aerobic and anaerobic zones, shallow & deep
pool biocells

20. • Treated Leachate Constituents – BOD/COD
• Processes
- Microbiota growth
- Precipitation
- Decomposition producing CO2 used by macrophytes
• Conditions – Aerobic and anaerobic zones, shallow & deep
pool biocells, nutrient source needed

21. • Treated Leachate Constituents – Sodium
Chloride, Calcium Chloride
• Processes
– Chlorides pass through
– Clay Sorption
– Sulfate to Sulfide
• Conditions – Maintain basic pH, submerged soils, soil
amendments, harvest plant material, warm
temps, oxidizing environment, nutrients, carbon, bacteria

22. • Treated Leachate Constituents –
Zinc, Copper, Lead, Chromium, Arsenic, Nickel, Cadmium
, Iron
• Processes
– Sorption and desorption (pH)
– Dissolution of carbonate bound metals (pH)
– Decomposition of metal organic complex compounds (pH)
– Hydroxides and Oxyhydrates (redox)
– Water column adsorption
– Sedimentation
– Soil amendments (peat)
• Conditions – adjust pH (metal dependent)

23. Project Examples

24. Saline County Landfill Biocell

25. Saline County Landfill
Design Considerations
• Fe, BOD, TDS
• Groundwater and leachate contaminants at the Saline
County, Illinois landfill are less than what we see at other landfills
• Hydraulic detention time (flow path, baffles)
• Basin slope
• Vegetative community for maximum treatment
• Dry weather water balance
• Addition of specialized treatment cell material (peat)

26. Saline County Landfill
Design Components
• A two-cell treatment biocell is proposed to address contaminant
loads:
1. A shallow flow cell to reduce BOD concentrations.
2. A deeper, peat-based cell for treatment of metals and Total
Dissolved Solids
* Note: The TDS concentrations in the Saline County landfill leachate do not appear to
reflect high concentrations of sodium or chloride, thereby making the removal more
effective.

27. Concept Plan - Vernon County Landfill
Biocell Treatment Processes

28. Concept Plan - Vernon County Landfill
Biocell Treatment Processes

29. Vernon County Landfill Biocell

30. Vernon County Landfill
Constituent: Typical Ranges:
1,1,1-Trichloroethane ND-4.62 mg/L
Chlorobenzene 1.19-2.88 mg/L
Ethylbenzene ND-17.2 mg/L
Methyl Ethyl Ketone ND-248 mg/L
m,p-Xylenes 11.2-39.2 mg/L
Methyl Chloride ND-28.9 mg/L
o-Xylene 15.3-22.4 mg/L
Tetrahydrofuan 157-508 mg/L
Toluene ND-50.2 mg/L
trans-1,2-Dichloroethylene ND-7.58 mg/L
Vinyl Chloride ND-2.03 mg/L
* other organic constituents non detectable (ND)

31. Vernon County Landfill
Vernon County Landfill - Leachate Volume in tons
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year End
2010 625.7 646.85 414.25 696.49 721.74 1223.9 3034.86 2867.01 2013.1 549.54 429.19 379.15 13601.78
2009 448.78 495.51 903.81 862.86 868.5 848.11 573.72 534.69 801.87 842.35 701.59 355.24 8237.03
2008 827.4 653.02 870.64 1431.07 2471.46 1780.5 1542.59 430.03 621.74 585.4 566.21 300.18 12080.24
2007 289.15 196.84 866.8 680.66 612.52 557.84 491.6 2482.81 2066.47 1684.63 342.33 372.21 10643.86
Vernon County Landfill - Leachate Volume in gallons (gallon of leachate = 7.8 lb)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year End
2010 160,436 165,859 106,218 178,587 185,062 313,821 778,169 735,131 516,179 141,025 110,000 97,180 3,487,667
2009 115,072 127,054 231,746 221,246 222,692 217,464 147,108 137,100 205,608 215,987 179,895 91,087 2,112,059
2008 212,154 167,441 223,241 366,941 633,708 456,538 395,536 110,264 159,421 150,103 145,182 76,969 3,097,497
2007 74,141 50,472 222,256 174,528 157,056 143,036 126,051 636,618 529,864 431,956 87,777 95,438 2,729,195

32. Vernon County Landfill
• Nitrogen, vertical & horizontal flow
• Phase 1 storage and demonstration biocells built in 2012
• Bio-treatment demonstration, quantify results to WDNR
• Phase 2 as a part of clay borrow for cap
• Regulatory hurdles

33. VernonCounty Landfill
Design Components