SEPA NRMRL \ NATIONAL RISK MANAGEMENT RESEARCH LABORATORY www.epa.gov/nrmrl GROUND WATER AND ECOSYSTEMS RESTORATION RESEARCH Transport and Fate of Nitrate and Pathogens at a Dairy Lagoon Water Application Site: An Assessment of CNMP Performance Research Type and Organization The research type is an Interagency Agreement (DWI292189901) with the U.S. Salinity Laboratory and the U.S. Department of Agriculture's Agriculture Research Service. Project Period April 1, 2005 through September 30, 2009 Project Summary EPA currently requires that application of concentrated animal feeding operation wastes to agricultural fields follows a Nutrient Management Plan (NMP). The tacit assumption is that a well-designed and executed NMP ensures that all lagoon water contaminants (nutrients and pathogens) are retained or taken up in the root zone so that ground water is inherently protected. The proposed research is designed to test the assumption that appropriate NMPs are protective of ground water and to address potential weaknesses in the land-application design and operation processes. A well-designed and managed CNMP was implemented on 5-by-l 0-meter plots at a dairy farm in San Jacinto, California, for four years using different forage and application patterns. The selected site was intensively characterized and instrumented for the experimental studies. Lagoon water application rates were determined by following NMP protocols established in consultation with the National Resource Conservation Service (NRCS). Spatial and temporal variations in water, nutrient, and indicator microbe levels at the site were determined using a system of nested tensiometers/soil solution samplers, neutron probe readings, drain gauges, and monitoring wells, as well as periodic soil coring, plant tissue analysis, and apparent soil electrical conductivity measurements. Along with the field experiments, laboratory experiments were also conducted, using microbes, lagoon water, well water, and soils from the NMP field site. Microcosm and batch studies were conducted to quantify microbial growth, death, and inactivation, as well as equilibrium partitioning of microbes at the solid-water and air-water interfaces. Transport experiments were conducted to quantify the influence of water content, microorganism size, grain-size distribution, and lagoon water composition on the movement and retention of microbes. The National Risk Management Research Laboratory's mission is to advance scientific and engineering solutions that enable EPA and others to effectively manage current and future environmental risks. NRMRL possesses unique strengths and capabilities and is dedicated to providing credible technological information and scientific solutions that support national priorities and protect human health and the environment. ------- Kinetic transport parameters were estimated by fitting numerical simulations to experimental data. Nitrate and indicator microbe transport and fate at the field site were modeled using an unsaturated zone water flow and solute transport model (HYDRUS ID and 2D) capable of simulating preferential flow paths. This project is completed and has resulted in multiple journal articles that provide detailed information on the various aspects of the project. A final EPA report is in progress to summarize these results. Products Leij, F.J. and S.A. Bradford. (In review). "Combined Physical and Chemical Nonequilibrium Transport Model: Analytical Solution, Moments, and Application to Colloids/' J. Contain. Hydrol. Segal, E., P. Shouse, J.A. Poss, D.M. Crohn, and S.A. Bradford. (In review). "'Strategies for Nutrient Management Plans in a Semi-Arid Environment.".^gricul. Ecosys. Environ. Bradford, S.A. and E. Segal. (2008). "Fate of Indicator Microorganisms Under Nutrient Management Plan Conditions." J! Environ. Qual., 38: 1728-1738. Bradford, S.A., E. Segal, W. Zheng, Q. Wang, and S.R. Hutchins. (2008). "Reuse of CAFO Wastewater on Agricultural Lands.'' J. Environ. Qual., 37: S97-S115. Bradford, S.A., S. Torkzaban, F. Leij, J. Simunek, and M.Th. van Genuchten. (2008), ^'Modeling the Coupled Effects of Pore Space Geometry and Velocity on Colloid Transport and Retention." Water Resources Res., 45. W02414, doi:10.1029/2008WR007096. Segal, E., P. Shouse, and S.A. Bradford. (2008). "Deterministic Analysis and Upscaling of Bromide Transport in a Fleterogeneous Vadose Zone." Vadose Zone J., 8: 601-610. Segal, E., S.A. Bradford, P. Shouse, N. Lazarovitch, and D. Corwin. (2008). "Integration of Hard and Soft Data to Characterize Field-Scale Hydraulic Properties for Flow and Transport Studies." Vadose Zone J., 7: 878-889. Tazehkand, S.S., S. Torkzaban, S.A. Bradford, and S.L. Walker. (2008). "Cell Preparation Methods Influence E. coli D2lg Surface Chemistry and Transport in Saturated Porous Media." J. Environ. Qual., 37: 2108-2115. Torkzaban, S., S.A. Bradford, M.Th. van Genuchten, and S.L. Walker. (2008), "Colloid Transport in Unsaturated Porous Media: The Role of Water Content and Ionic Strength on Particle Straining." J. Contam. Hydro!., 96: 113 127. Zheng, W., S R. Yates, and S.A. Bradford. (2008), 'Analysis of Steroid Hormones in Dairy Manure and Wastewaters." Environ. Sci. Techno/.. 42: 530-535. Bradford, S.A. and N. Toride. (2007). "A Stochastic Model for Colloid Transport and Deposition." J. Environ Qual, 36: 1346-1356. Bradford, S.A., S. Torkzaban, and S.L. Walker. (2007). "Coupling of Physical and Chemical Mechanisms of Colloid Straining in Saturated Porous Media." Water Res., 41: 3012-3024. Contact Scott Bradford The National Risk Management Research Laboratory's mission is to advance scientific and engineering solutions that enable EPA and others to effectively manage current and future environmental risks. NRMRL possesses unique strengths and capabilities and is dedicated to providing credible technological information and scientific solutions that support national priorities and protect human health and the environment. Work Shed Blending -Wheitgnu (years 1-2) Alfalfa (years 3 -1) s Fenee 7 Seniors ~ N Volitil. Chamber Rkii Gauge. ) Culvert Pipes ^ Weather Station I Lagoon Water O Lysitneler Evaporation Pin ¦ EC Probes Soil core location / Ne»Urmi Access ------- |