2008 Progress Report: An Innovative System for Bioremediation of Agricultural Chemicals for Environmental Sustainability
EPA Grant Number:
An Innovative System for Bioremediation of Agricultural Chemicals for Environmental Sustainability
Davidson, Paul C.
University of Illinois at Urbana-Champaign
EPA Project Officer:
July 7, 2007 through
July 6, 2009
Project Period Covered by this Report:
July 7, 2007 through July 6,2008
P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet - Phase 2 (2007)
Pollution Prevention/Sustainable Development
P3 Challenge Area - Agriculture
Description of Project
Like many feats of engineering, the introduction of subsurface tile-drainage in agriculture brought with it many changes. Many of these changes were positive; millions of acres of the most fertile soils in the world were utilized for agricultural production in the Midwest and elsewhere with the help of tile drainage. However, not all of the changes were positive. Subsurface drainage by its very essence gives gravitational water easy access to waterways that lead to larger water bodies. This excess water often carries with it nutrients and agricultural chemicals, such as nitrate, atrazine, and alachlor, which can have serious consequences on both people and the environment.
Although the usage of these substances is quite common, the effects of water contamination can be very harmful. Atrazine has been shown to cause muscle degeneration, cardiovascular damage, and cancer when exposure is long-term. Nitrate also has hazardous effects; it is linked to blue-baby syndrome and non-Hodgkin’s lymphoma. Excess nitrogen also causes eutrophication of surface waters from excessive algae growth. The hypoxia problem caused by nitrate pollution from agricultural fertilizers flowing into the Mississippi River has grown by a factor of 80 in the past thirty years (Gulf of Mexico Hypoxia Education, 2007). Alachlor is a harmful pesticide that is easily leached into subsurface drainage systems, capable of causing chronic health conditions such as kidney failure and even cancer (U.S. Environmental Protection Agency, 2005).
The large amount of pollution reaching water systems, and the effects of this pollution necessitates that this problem be addressed. Bioremediation systems appear to be a step towards solving this problem. Preliminary research has shown that woodchips have the capacity to reduce concentrations of these chemicals by treating subsurface drainage before it exits agricultural lands. This research aims to find the most successful media for the filtration process, as well as to develop design criteria for effective and efficient field systems. Retention time and the process of nutrient removal will also be studied.
The qualitative benefits to society, economic prosperity, and environmental sustainability are significant and numerous. The goal of this research is to help improve the sustainability of current farming practices without reducing agricultural production. The results show that readily available and renewable resources, namely woodchips, are capable of reducing contaminants in subsurface water. Water quality is of utmost importance in ensuring both environmental and human health, globally. Biofiltration also has great economic advantages by providing agricultural producers with a tool to minimize chemical leaching from their fields and reduce future regulation costs and, in some instances, even qualifying them for conservation subsidies. In addition, the environmental benefits of our findings are enormous. The biofilters are composed of a byproduct that would typically be disposed of. If this biofilter system can be installed in a vast majority of agricultural watershed in the Mississippi River Valley, this may provide a grass-root level solution to the Hypoxia problem in the Gulf of Mexico, and be a precedent for nutrient reduction is drainage water around the world.
The overall objective of this project is to design, implement, and evaluate a renewable, naturally available biofilter to minimize the transport of chemicals from agricultural watersheds into surface water sources.
The specific objectives of this project are:
1. To implement a field-scale biofilter based on results from Phase I and evaluate its effectiveness.
2. To continue evaluating the efficiency of materials for bioremediation of aqueous contaminants.
3. To investigate how retention time affects bioremediation of aqueous contaminants.
4. Based on results from objective (3), provide recommendations to implement biofilter technology to reduce contaminant discharge from septic systems and wastewater treatment facilities.
5. Implement a biofiltration system at GB Pant University of Agriculture and Technology in India to address water quality issues there.
The following assisted with this research:
Dept. of Agricultural and Biological Engineering, UIUC: Stephen M. Anderson, J. Malia Appleford, Elizabeth Brooks, Greg J. Byard, Paul C. Davidson, Gina Francis, Greg E. Goodwin, Daniel J. Koch, Jacob Mitchell, Amanda J. Olsen, Siddartha Verma, Curtis Zurliene
Dept. of Civil and Environmental Engineering, UIUC: Joseph F. Good
Dept. of Chemistry, UIUC: Brandon Kocher, Debapriya Mazumdar
The preliminary results from our field-scale experiments support our hypothesis that a properly designed, naturally available biofilter can significantly reduce the amount of nutrients leaving agricultural fields.
Biofilters, which use microorganisms to remove pollutants, are a promising treatment for leached agricultural contaminants. Previous lab research from Phase I investigated reduction pathways and the suitability of different filter substrates for bioremediation. Current efforts focus on installed field-scale biofilters to determine effectiveness in actual field conditions.
In 2007, the group installed two real-world biofilter systems at two different watersheds on tiled farm fields in Illinois. Currently, the group is monitoring the systems and collecting data on the efficiency of the biofilters in reducing the amount of chemicals draining into rivers and streams.
Preliminary Field Results
Weekly samples are taken from the biofilter inlet and outlet. The DeLand biofilter is comprised of a mixture of hardwood and softwood woodchips while the Monticello biofilter was made purely of hardwood woodchips.
Since microbial activity increases with higher temperatures, the data from DeLand supported our hypothesis that the outlet concentration would be lower than the inlet. These results from DeLand are from the biofilter containing a mixture of woodchips (both hardwood and softwood) and consistently showed a lower outlet concentration. As the biofilter efficiency continued to improve, the outlet nitrate concentration was consistently below the drinking water standards of 10 mg/L. Also, as the microbial community continues to grow due to a sufficient carbon source, we expect the reduction to continue to improve.
The data from the Monticello site showed only a slight difference between the inlet and outlet concentrations. This finding can be explained by realizing that hardwood woodchips do not work as well as found in laboratory experiments (Phase I), or simply due to the fact that it may take longer for the fungi to break down the woodchip carbon to a usable form for the denitrifying bacteria. Continued monitoring will provide additional insight to this issue.
Biofilter Pulse Tests
Experiments were also performed on the field-scale biofilters. A pulse of nitrate solution (500 g NO3-N) was introduced at the inlet of both systems. Samples were taken at the inlet, monitoring wells, and outlet to allow for spatial and temporal modeling of nutrient reduction as a high concentration pulse passes through the system. Results from this test showed a significant reduction for both biofilters. Even with extremely high initial concentrations (26000 mg/L) we observed a 65% reduction in nitrate mass. Continued monitoring will allow us to determine whether hardwood woodchips work as effectively as a mixture (or softwood), or if the hardwoods merely take longer to begin working (and possibly have a longer lifespan).
Lab tests focused on determining reduction pathways for chemical species including atrazine, alachlor, and phosphorus. The sampling approach attempted to discern biological from physical reductions. Incomplete denitrification can stop at N2O, a greenhouse gas. Our preliminary lab findings, using the acetylene inhibition test, suggest that denitrification proceeds to completion when biofilter media are tested. The biofilter media reduced pesticide concentrations by over 50%. Pesticide reductions were observed to result from adsorption onto biofilter media and not from biological activity. The biofilter media reduced phosphates approximately 25% in the lab, with two-thirds of the reduction due to biological activity.
During the 2007-08 winter break, the group traveled to India and installed a similar biofiltration system at the GB Pant University of Agriculture and Technology, approximately 300 km northeast of Delhi. The system was installed successfully with locally available eucalyptus woodchips. A satellite data monitoring system was installed to upload recorded water depth, rainfall, and temperature data to a web server which can be accessed from any web portal.
Our research efforts received notice not only from various University officials including the Vice-Chancellor (President) of GBPUAT, but also attracted the Uttarakhand State Agriculture Secretary. Local newspapers published the success of the US team in India. Since that time, the group has received requests to collaborate further on bioremediation systems for local aquaculture industries.
The work in India shows that it is possible to implement a similar technology to address water quality issues. Future results from our biofilter in India will hopefully show that any naturally-available carbon source can be used in this system.
Future work involves continued monitoring of the field sites. From this, the effectiveness of the biofilters installed in the U.S. and India will be compared. Lastly, the collected data will be used to develop mathematical relationships between retention times and chemical reductions in hopes to eventually model the system.
In summary, the findings of this research have significant benefits and potential impacts on the quality of life for many people in the United States and the rest of the world. The reduction of water contaminants would reduce human health risks, reduce hypoxia problems, and improve wildlife habitat. It can further reduce financial risk for agricultural producers and possibly be implemented in other industries as well.
Gulf of Mexico Hypoxia Education, The Dead Zone: Hypoxia in the Gulf of Mexico
Overview. http://www.gulfhypoxia.net/education/_resources/Dead_Zone/Dead_Zone_Overview.ppt [October 26, 2007].
U.S. Environmental Protection Agency. 2005. Consumer Fact Sheet on: NITRATES/NITRITES.
Progress and Final Reports:
P3 Phase I:
Solar-Powered LED Lanterns for the Replacement of Oil Lamps in the Developing World
| Final Report