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INVESTIGATOR: Christianson, L.; Christianson, L.

PERFORMING INSTITUTION:
IOWA STATE UNIVERSITY
2229 Lincoln Way
AMES, IOWA 50011

PERFORMANCE AND ACCEPTANCE OF DENITRIFICATION BIOREACTORS FOR AGRICULTURAL DRAINAGE

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.

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.