Source: IOWA STATE UNIVERSITY submitted to
PERFORMANCE AND ACCEPTANCE OF DENITRIFICATION BIOREACTORS FOR AGRICULTURAL DRAINAGE
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
TERMINATED
Funding Source
Reporting Frequency
Annual
Accession No.
0226042
Grant No.
2011-67011-30648
Project No.
IOW05302
Proposal No.
2010-05253
Multistate No.
(N/A)
Program Code
A7101
Project Start Date
Aug 15, 2011
Project End Date
Aug 14, 2013
Grant Year
2011
Project Director
Christianson, L.
Recipient Organization
IOWA STATE UNIVERSITY
2229 Lincoln Way
AMES,IA 50011
Performing Department
Agri & Biosystems Engineering
Non Technical Summary
This work aims to enhance water quality in regions impacted by agricultural drainage by improving the performance and understanding of denitrification bioreactors, one of the newest technologies for practical edge-of-field nitrate removal. Simply put, by routing drainage water through a woodchip-filled excavation, bioreactors can maximize the conversion of nitrate in the drainage to benign nitrogen gas (denitrification) before the water reaches the local stream or river. Because this is a new technology, two integrated research/extension objectives are proposed: (1) Assess and model field-scale denitrification bioreactor nitrate removal performance, and (2) Study how increased education of water quality technologies, including denitrification bioreactors, can improve their perception among landowners. By interweaving bioreactor nitrate removal data and modeling with extension education, cutting edge information will be provided to landowners about water quality technologies enabling their informed decision making. Expected outcomes include more effective denitrification bioreactor designs and changes in understanding of nitrate reduction strategies due to increased education. Through insights gained from this work, denitrification bioreactors will allow Midwestern agriculture to increase productivity in order to combat world hunger while concurrently addressing long-term competitiveness through environmental sustainability.
Animal Health Component
100%
Research Effort Categories
Basic
(N/A)
Applied
100%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
1120210301025%
1120210308025%
1330210202050%
Goals / Objectives
Midwestern water quality groups and government officials have significant interest in the potential of denitrification bioreactors to improve water quality in this region. Because of this, installation of denitrification bioreactors has moved ahead of scientific and engineering knowledge of how these systems work. Due to the call for increased agricultural production in conjunction with local and national nitrate water quality issues, there is an urgent need for this bioreactor research and extension programming. This proposal's goal is to enhance water quality in regions impacted by agricultural drainage by improving the performance and understanding of denitrification bioreactors through integrated research and extension activities. By integrating the latest denitrification bioreactor performance data into a new water quality extension program, this work will enable science-based, informed decision making by landowners. These integrated research/extension needs are addressed with two proposed objectives. Objective #1 "Field Scale Performance Prediction Modeling" aims to assess factors affecting in situ bioreactor nitrate removal performance and use this to develop a performance prediction model. This will be evaluated through a rigorous statistical analysis of field data (January 2011 - August 2011) which will then be used to develop a performance prediction model for denitrification bioreactors (August 2011 - October 2011). The major outputs from Objective #1 will be a denitrification bioreactor fact sheet, a conference presentation and peer-reviewed journal manuscript. Objective #2 "Economic Valuation and Social Acceptance" will allow study of how increased education of water quality technologies, including denitrification bioreactors, can improve landowners' perceptions of them. A comparison of economic costs/benefits and ecosystem services provided by six nitrate reduction methods (wetlands, controlled drainage, cover crops, crop rotation, nutrient management, and denitrification bioreactors) will be done (January 2011 - April 2011) followed by development of an educational program which will include a producer survey evaluation of the social acceptance of these six methods (March 2011 - August 2011). The major outputs for this objective are an educational comparison matrix handout, a peer-reviewed publication and a possible conference presentation.
Project Methods
This work consists of two interdependent objectives that address information gaps critical to optimizing denitrification bioreactor design as well as accelerating stakeholders' knowledge of this new water quality strategy. With Objective #1, it is hypothesized that denitrification bioreactor design parameters and field conditions affect in situ performance. This will be evaluated through a rigorous statistical analysis of field data (January 2011 - August 2011) which will then be used to develop a performance prediction model for denitrification bioreactors (August 2011 - October 2011). Data from four existing denitrification bioreactors in Iowa will be collected with relevant parameters including: length: width ratio (L:W), cross sectional shape, flow, temperature, NO3--N influent and effluent concentration, retention time, hydraulic loading, and cost. For the bioreactors managed by ISU, water samples will be analyzed in the ISU Agricultural and Biosystems Engineering Water Quality Laboratory (Lachat Quick-Chem 8000 automated analyzer) and flow data will be collected with in situ monitoring (Solinst Levelogger pressure transducers, Isco 2150 area velocity meter). To minimize variability associated with field studies, several years of data from the four sites managed by multiple groups will allow for a strong multiple regression analysis of parameters and their interactions. Differences between sites will be tested by using least significant difference t-tests in SAS statistical software. It is expected that increased retention time, L:W, and temperature will increase nitrate mass removals. Objective #2 will comprise a comparison of economic costs/benefits and ecosystem services provided by six nitrate reduction methods (wetlands, controlled drainage, cover crops, crop rotation, nutrient management, and denitrification bioreactors) (January 2011 - April 2011) followed by development of an educational program which will include a producer survey evaluation of the social acceptance of these six methods (March 2011 - August 2011). By bringing together such new relevant research, this educational program aims to accelerate the diffusion of information about water quality technologies hopefully increasing the rate these technologies are tested. The economic parameter for evaluation of the six technologies will be the cost per pound of nitrate removed as estimated from custom rate surveys and literature, with ecosystem services also synthesized from literature. The resulting information will be used to develop an educational program given at five ISU Extension Field Days and similar events. Producers in attendance will have the opportunity to answer survey questions about their background, their understanding of the technologies and their interest in implementing one or a combination. The survey will also be given at Extension events where the program has not been presented in order to obtain control baseline data. A combination of categorical and numerical data will be collected and reported using means, medians, frequencies of occurrence and similar statistical formats.

Progress 08/15/11 to 08/14/13

Outputs
Target Audience: As stated in the 2012 Progress Report: “The target audience for the Extension water quality program as well as the Extension publication was farmers in the US Midwest doing subsurface agricultural drainage. An additional audience for the Extension publication, as evidenced by email inquiries received by the PD and collaborators, was drainage and water quality professionals who are now interested in learning more about denitrification bioreactors as a new water quality improvement option.” Changes/Problems: Project modifications were described previously in the 2012 Progress Report; no further modifications were made as the PD’s grant/fellowship tenure ended in December 2011, upon the PD’s commencement. What opportunities for training and professional development has the project provided? The PD participated in the NIFA Fellows Conference in August 2012 at USDA and NIFA headquarters in Washington DC; meeting with other fellows to discuss research and hearing from USDA officials about the agency was informative. For the most part, considering the PD graduated in December 2011 (thus terminating the fellowship period), the training and professional development opportunities were consistent with those described below in the dissemination section. Invited and conference presentations allowed the PD to gain experience with public speaking and results dissemination, while Field Day presentations and the farmer discussion group gave the PD direct experience talking with and listening to farmers. How have the results been disseminated to communities of interest? Results dissemination to the scientific community consisted of generation of eight peer-reviewed publications and one Ph.D. dissertation. Additionally, the PD gave two conference presentations, one webinar, and five invited presentations at water quality meetings where scientists, extension agents, drainage/environmental/water professionals, and/or NRCS employees were in attendance. Dissemination of results to the farming community included five field events (see description of project activities) and several radio interviews, one of which was for Successful Farming, a nationally syndicated show. Please see the publications section for more detail on specific publications. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Considering the PD of this fellowship grant graduated in December 2011 (thus terminating the fellowship period), the accomplishments are consistent with accomplishments listed in the 2012 Progress Report: “The goal of Objective 1 was to enhance scientific understanding by identifying the key design and environmental factors affecting bioreactor performance and to facilitate more effective designs though model development. The resulting “change in knowledge” outcome was based upon water quality data from four bioreactors in Iowa that showed total annual nitrate-nitrogen load reductions ranged from 12 to 57% (mean 32%). Multiple regression models showed temperature and influent nitrate concentration were the most important factors affecting percent bioreactor nitrate load reduction and nitrate removal rate, respectively. This analysis also indicated load reductions within the bioreactor were significantly impacted by drainage water retention time at three of the four reactors. These data greatly enhanced understanding of bioreactor performance in the field and provided information to further refine the design model. Moreover, there is now evidence of a “change in condition” outcome as the water quality at these four bioreactors sites has been shown to be improved. Several proposed outcomes for Objective 2 included (1) increased knowledge of costs and benefits of the seven nitrate reduction strategies for producers and landowners, as well as (2) assessment of factors limiting implementation of these nitrate reduction strategies. A “change in knowledge” outcome was facilitated by the cost efficiency comparison as it was found springtime nitrogen application and nitrogen application rate reduction were the most cost effective practices, and the in-field vegetative practices of cover crop and crop rotation were the least cost effective. With means of less than $3 per kg N removed per year, controlled drainage, wetlands, and bioreactors were fairly comparable with each other. In context of farmer perception of the practices, the two nitrogen management practices were shown to be accessible and realistic options for water quality improvement as they elicited high interest and had the highest level of compatibility. However, these practices did not provide numerous other ecosystem services. Conversely, wetlands had a high ecosystem service count, but were perceived to have low compatibility and survey respondents showed lower interest in this practice. The practice of cover cropping showed more moderate, yet consistently positive, results for all factors. Bioreactors were recognized as a straightforward and efficient water quality improvement technology, but this practice provided few additional ecosystem services, was perceived to have only midrange compatibility with existing farm management goals, and was associated with high costs that may limit implementation.”

Publications

  • Type: Theses/Dissertations Status: Published Year Published: 2011 Citation: Christianson, L. 2011. Design and performance of denitrification bioreactors for agricultural drainage. PhD diss. Agricultural and Biosystems Engineering, Iowa State University. Ames, Iowa.
  • Type: Journal Articles Status: Published Year Published: 2012 Citation: Christianson, L. E., N. Hoover, A. Bhandari, and M. J. Helmers. 2012. Technical Note: The potential of municipal yard waste to be denitrification bioreactor fill. Applied Engineering in Agriculture 28(6): 853-859.
  • Type: Journal Articles Status: Published Year Published: 2012 Citation: Christianson, L. E., A. Bhandari, and M. J. Helmers. 2012. A practice-oriented review of woodchip bioreactors for subsurface agricultural drainage. Applied Engineering in Agriculture 28(6): 861-874.
  • Type: Journal Articles Status: Published Year Published: 2012 Citation: Christianson, L., A. Bhandari, M. Helmers, K. Kult, T. Sutphin, and R. Wolf. 2012. Performance evaluation of four field-scale agricultural drainage denitrification bioreactors in Iowa. Transactions of the ASABE 55(6): 2163-2174.
  • Type: Journal Articles Status: Published Year Published: 2013 Citation: Christianson, Laura, Matthew Helmers, Alok Bhandari, and Thomas Moorman. 2013. Internal hydraulics of an agricultural drainage denitrification bioreactor. Ecological Engineering 52: 298-307.
  • Type: Journal Articles Status: Awaiting Publication Year Published: 2013 Citation: Christianson, Laura, Reid Christianson, Matthew J. Helmers, Carl Pederson, and Alok Bhandari. 2013 (pre-print available online). Modeling and calibration of drainage denitrification bioreactor design criteria. J. Irrigation and Drainage Engineering 10.1061/(ASCE)IR.1943-4774.0000622 (Apr. 1, 2013).
  • Type: Journal Articles Status: Accepted Year Published: 2013 Citation: Christianson, Laura, John Tyndall, and Matthew Helmers. (Accepted 10 May 2013, under re-review for Water Resources and Economics) Financial comparison of seven nitrate reduction strategies for Midwestern agricultural drainage.
  • Type: Journal Articles Status: Other Year Published: 2013 Citation: Christianson, Laura, Tricia Knoot, Drake Larsen, John Tyndall, and Matthew Helmers. (Accepted 11 July 2013, under revision for International Journal of Agricultural Sustainability) Adoption potential of nitrate mitigation practices: an ecosystem services approach .


Progress 08/15/11 to 08/14/12

Outputs
OUTPUTS: Activities: Objective 1 activities involved analysis of nitrate-removal performance data from four field-scale denitrification bioreactors in Iowa and the use of these data to develop bioreactor performance prediction models. Additional tracer testing and piezometer sampling was implemented at one bioreactor based on Objective 1 results. Objective 2 included the development of cost efficiencies for seven drainage water quality improvement strategies. This information, along with a comparison of ecosystem services of the seven practices, was used to create an Extension-type field educational program. In addition to the analysis of survey data from these program participants, a farmer discussion group was held to gain better understanding of farmer perceptions of these practices. Events: The educational program comparing the seven drainage water quality technologies was presented, as proposed, at five Iowa Learning Farms field-events throughout the state of Iowa during summer 2011. Following this, the PD successfully defended her Ph.D. on 3 October 2011, and an estimated 40-50 individuals, including USDA engineers and researchers (one from out-of-state) and commodity group representatives, attended the defense. The PD was an invited presenter at several conferences during the project period, including: Managing Water. Harvesting Results - America's Ag Water Management Summit. Bloomington, MN. October 2011. Eastern South Dakota Water Conference: Water Management in Extreme Conditions. Brookings, SD. October 2011. USDA NIFA Water Quality Conference. Portland, OR. May 2012. Additionally, the PD has been involved in several radio interviews, one of which was for Successful Farming, a nationally syndicated show ("Bioreactors Improve Water Quality", aired 18 July 2012, available at: http://www.agriculture.com/media-center/radio). Service and Product Dissemination: A primary broad-audience publication from this reporting period, a four page Extension publication, has circulated widely based upon the amount of PD email traffic it has generated, even from parties outside the US Midwest (e.g., California, Denmark, Ireland). This publication recently received a 2012 Blue Ribbon Educational Aids Award from the American Society of Agricultural and Biological Engineers (ASABE) additionally increasing its exposure. The PD and this work have been highlighted in a USDA NCR-SARE Profile from the Field ("Iowa Student Studies Woodchip Bioreactors for Nitrate Reduction in Agricultural Drainage", available at: http://www.northcentralsare.org/Educational-Resources/From-the-Field/ North-Central-SARE-From-the-Field/Iowa-Student-Studies-Woodchip-Biore actors-for-Nitrate-Reduction-in-Agricultural-Drainage). This profile link allows access to a supplementary cost efficiency handout used in the field events. Lastly, the denitrification bioreactor design model, which underwent refinement during this project, and associated resulting bioreactor designs developed by the PD and collaborators have been shared with researchers and USDA NRCS engineers throughout the region including those from Iowa, South Dakota, Minnesota, Wisconsin, and Canada. PARTICIPANTS: Dr. Mathew Helmers, Associate Professor of Agricultural and Biological Engineering at Iowa State University, was a co-advisor to the Fellowship Grant PD, Laura Christianson. Because a key component of this proposal involved extension programming, Dr. Helmers took a role in oversight of the extension program development and was a key contact for working with the Iowa Learning Farms. Dr. Alok Bhandari, Department Head of Civil Engineering at Kansas State University, was a co-advisor to the Fellowship Grant PD, Laura Christianson. Dr. Bhandari showed commitment to the PD's training in written and oral communications by providing her classroom teaching experiences and grant writing opportunities. Dr. John Tyndall, Assistant Professor in the Department of Natural Resource Ecology and Management at Iowa State University, was a Ph.D. committee member for the Fellowship Grant PD, Laura Christianson. Dr. Tyndall provided assistance with the economics and cost-efficiency portion of the study as well as helped coordinate the farmer discussion group. The Iowa Soybean Association (ISA) played a role in both objectives of the study. First, two of the four bioreactors compared in the nitrate-removal performance evaluation were operated and maintained by the ISA. Data collection was completed by their staff and the resulting data were shared with the PD for analysis. Secondly, ISA hosted the farmer discussion group. Iowa Soybean Association farmer members served as the invited population for the group and the event was held at the ISA headquarters facility. The Iowa Learning Farms allowed the PD to present the water quality educational program described here at their field events throughout summer 2011. The Learning Farms staff also oversaw the development of the farmer survey and assisted in survey distribution and resulting data compilation. TARGET AUDIENCES: The target audience for the Extension water quality program as well as the Extension publication was farmers in the US Midwest doing subsurface agricultural drainage. An additional audience for the Extension publication, as evidenced by email inquiries received by the PD and collaborators, was drainage and water quality professionals who are now interested in learning more about denitrification bioreactors as a new water quality improvement option. PROJECT MODIFICATIONS: There were no major problems or delays that had significant impact on the rate of expenditure and no significant deviations, unexpected outcomes, or changes in objectives during the reporting period. Minor changes to the methods included: Nitrate removal data from only four bioreactors were compared rather than five as proposed due to poor functioning at the fifth site. However, additional testing was completed at one of the four bioreactors which resulted in an additional peer-reviewed publication (currently submitted with revisions). In the development of cost efficiencies for drainage water quality practices, it was proposed to compare six practices. However, the proposed practice of "nutrient management" was divided into the two practices of "spring N application" and "reduced N application rate", resulting in a comparison of seven total practices. Also, only farm-level cost efficiencies were developed; the additionally proposed development of watershed-level cost efficiencies was decided to be too complex for this Ph.D. project. The farm-level cost efficiencies were used to create an educational program given at five field events across the state. These five events were felt to provide a more representative sample population than the originally proposed "...two large Extension events held at the ISU Agronomy and Agricultural Engineering Research Farm near ISU's campus ...[and at] an event hosted at the Northeast Research and Demonstration Farm in Northeast Iowa...". Moreover, handouts, rather than the proposed posters, were an integral program component as this gave the attendees something to take home. The handouts were also easier to see and handle than posters in a field day setting. In terms of program survey development, this was done in collaboration with the Iowa Learning Farms staff rather than with project collaborator Dr. John Tyndall. Dr. Tyndall nevertheless assisted a great deal with the cost efficiency methodology. Importantly, a farmer discussion group was added to the project in order to provide more in-depth data to supplement the farmer survey data. The farmer discussion group held in September 2011 in collaboration with the Iowa Soybean Association (ISA) required additional IRB approval which was received on 5 August 2011 (IRB No. 11-343). The survey associated with the field events had previously received IRB approval (IRB No 10-616).

Impacts
The goal of Objective 1 was to enhance scientific understanding by identifying the key design and environmental factors affecting bioreactor performance and to facilitate more effective designs though model development. The resulting "change in knowledge" outcome was based upon water quality data from four bioreactors in Iowa that showed total annual nitrate-nitrogen load reductions ranged from 12 to 57% (mean 32%). Multiple regression models showed temperature and influent nitrate concentration were the most important factors affecting percent bioreactor nitrate load reduction and nitrate removal rate, respectively. This analysis also indicated load reductions within the bioreactor were significantly impacted by drainage water retention time at three of the four reactors. These data greatly enhanced understanding of bioreactor performance in the field and provided information to further refine the design model. Moreover, there is now evidence of a "change in condition" outcome as the water quality at these four bioreactors sites has been shown to be improved. Several proposed outcomes for Objective 2 included (1) increased knowledge of costs and benefits of the seven nitrate reduction strategies for producers and landowners, as well as (2) assessment of factors limiting implementation of these nitrate reduction strategies. A "change in knowledge" outcome was facilitated by the cost efficiency comparison as it was found springtime nitrogen application and nitrogen application rate reduction were the most cost effective practices, and the in-field vegetative practices of cover crop and crop rotation were the least cost effective. With means of less than $3 per kg N removed per year, controlled drainage, wetlands, and bioreactors were fairly comparable with each other. In context of farmer perception of the practices, the two nitrogen management practices were shown to be accessible and realistic options for water quality improvement as they elicited high interest and had the highest level of compatibility. However, these practices did not provide numerous other ecosystem services. Conversely, wetlands had a high ecosystem service count, but were perceived to have low compatibility and survey respondents showed lower interest in this practice. The practice of cover cropping showed more moderate, yet consistently positive, results for all factors; this practice had the highest level of elicited interest, second highest compatibility ranking, and high perceived benefits. Bioreactors were recognized as a straightforward and efficient water quality improvement technology, but this practice provided few additional ecosystem services, was perceived to have only midrange compatibility with existing farm management goals, and was associated with high costs that may limit implementation.

Publications

  • Christianson, L. and Helmers, M. 2011. Woodchip bioreactors for nitrate in agricultural drainage. Iowa State University Extension Publication PMR 1008 (double blind expert-reviewed). Available at: https://store.extension.iastate.edu/ItemDetail.aspxProductID=13691
  • Christianson, L., Hoover, N., Bhandari, A. and Helmers, M. 2011. The Potential of Municipal Yard Waste to be Denitrification Bioreactor Fill. Oral presentation at the American Society of Agricultural and Biological Engineers (ASABE) 2011 Annual International Meeting. Louisville, Kentucky. 7-10 August 2011. Paper No. 1111036.
  • Christianson, L., Helmers, M. and Pederson, C. 2012. Hydraulic Performance of the Denitrification Bioreactor RFR-A11116. Iowa State University, Northeast Research and Demonstration Farm Annual Report ISRF11-13. Pages 23-24.