Bioremediation of Groundwater Contaminated with Agricultural Chemicals

1
Bioremediation of Groundwater Contaminated
with Agricultural Chemicals
Paul Davidson
University of Illinois at Urbana-Champaign,
Department of Agricultural and Biological
Engineering, pdavidso_at_uiuc.edu
Results

• Why is this research important?
• The infiltration and runoff of contaminants into
  surface and groundwater are of much concern when
  considering water quality.
• Nitrogen , atrazine, and alachlor enter
  groundwater and contaminate the water sources.
• In the presence of available phosphorus,
  nitrate-N causes excessive algal growth, leading
  to eutrophication.
• Health Problems
• Nitrate-N (10 ppm) Blue Baby Syndrome, Cancer
• Atrazine (3 ppb) Cardiovascular damage, Cancer
• Alachlor (2 ppb) Kidney and liver damage, Cancer
• Objectives
• Properly designed biofilters have the potential
  to reduce the concentration of agricultural
  chemicals. The biofilters provide essential
  nutrients to microorganisms to degrade these
  chemicals. The hypothesis of this research is
  that nitrate-N, atrazine and alachlor
  concentrations in the groundwater will be reduced
  if treated with biofilters.
• The overall objective of this research is to
  investigate and evaluate the effectiveness of a
  biofilter for reducing concentrations of
  agricultural chemicals in subsurface water.

• Conclusions
• Biodegradations of all three chemicals
  (nitrate-N, atrazine, and alachlor) have been
  achieved using woodchip biofilters.
• Depth does not have any significant effect.
• Preliminary testing showed that
• Biodegradation of Nitrate-N concentration has
  been significant in the presence of atrazine and
  alachlor.
• Results indicate that current agricultural
  management practices may need alterations for
  optimum yield and safer environment.

Figure 2. Soil columns used for research project.
Figure 4. Concentrations of chemicals in
subsurface samples.

• How did I approach my research?
• Research was performed in a controlled laboratory
  environment, where weather did not play a role in
  the experiments.
• Six soil columns were used (3 height, 15
  diameter).
• Three of the columns contained Drummer silty-clay
  loam, while the other three contained Thorp silt
  loam soil.
• Nitrogen, atrazine, and alachlor were applied
  separately, and in various combinations, to each
  of the columns.
• Tests were run to determine various properties of
  the biofilter, and to determine the amount of
  contaminants leaching through the soil profiles
  containing the biofilter.
• An experiment was run to determine the
  effectiveness of the woodchip biofilter.

References Cooke, R.A, A.M. Doheny and M.C.
Hirschi. 2001. Bio-reactors for edge-of- field
treatment of tile outflow. ASAE Paper No.
01- 2018. St.Joseph,MI. Doheny, Adrian. 2002.
Bio-reactors for edge-of-field treatment of tile
flow. M.S. thesis, Agricultural Engineering
Dept., University of Illinois,
Urbana. Eastburn, R.P. and W.F. Ritter. 1988. A
review of denitrification in on-site wastewater
treatment systems. Environmental Pollution
5149-61. Illinois Department of Public Health.
2005. Environmental Health Fact Sheet-Alachlor
and atrazine in groundwater. http//www.idph.stat
e.il.us/envhealth/factsheets/alachlor-atrazine.htm
April 4, 2005. Kadlec, R.H. and R.L. Knight.
1996. Treatment Wetlands. Boca Raton, FL CRC
Press, Inc. Nitrate Removal Technologies, LLC,
2001. Why are nitrates a problem?
http//www.nitrateremoval.com/whyare.htm
February 8, 2002. Schipper, L. and M.
Vojvodic-Vukovic. 2001. Five years of nitrate
removal, denitrification and carbon dynamics in
a denitrification wall. Water Resources 35(14)
3473-3477. U.S. Environmental Protection Agency.
2005. Consumer Fact Sheet on NITRATES/NITRITES.
http//www.epa.gov/safewater/contaminants/dw_con
tamfs/nitrates.html April 6, 2005 Wildman,
T.A. 2002. Design of field-scale bioreactors for
bioremediation of nitrate-N in tile drainage
effluent. 2002. Unpublished MS thesis,
University of Illinois, Urbana.

• These results show that the biofilter does reduce
  the concentrations of the contaminants.
• The biofilter at a shallow depth seems to be most
  effective, but a biofilter at any depth should be
  sufficient for lowering the concentrations below
  the Maximum Contaminant Level (MCL).

Table 1. Chemical concentration reductions by
biofilter densities.
Figure 3. Schematic diagram of the three
different columns of each soil type.
Figure 1. Woodchip biofilters.

• What to look For?
• What concentration of each contaminant leaches
  through the soil?
• Does the depth of the biofilter affect the rates
  of biodegradation of chemicals?
• Does the concentration of the leachates vary when
  various chemicals are applied in combination?

Application Schedule - NO3 (25 ppm), Atz. (25
ppb), Al. (25 ppb) week 1 NO3 week 4
Al. week 2 NO3 Atz. week 5 Atz.
Al. week 3 Atz. week 6 NO3 Atz. Al.
Atrazine C8H14ClN5
Alachlor C14H20ClNO2
Nitrate-N NO3
This research project was supported in part by
the Environmental Council at the University of
Illinois.
IMPORTANT The nitrate-N concentration was
reduced from 25 ppm to only 4.6 ppm when in the
presence of atrazine and alachlor. There was no
soil or biofilter media present in this case.