Analysis and Integration of Drain Systems and Watersheds with Phosphorus and Nitrogen Compounds

Amro A. El-Baz1, Kamal T. Ewida1, Eva M. Lovelady2, and Mahmoud M. El-Halwagi3. (1) Environmental Engineering, Zagazig University, Zagazig, Egypt, (2) Texas A&M University, The Artie McFerring Department of Chemical Engineering, College Station, TX 77843-3122, (3) The Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843-3122

Nitrogen and phosphorus compounds are among the most important species contributing to ecological cycles. In particular, the environmental and biological aspects of water systems and their surrounding systems are highly impacted by nitrogen compounds as they contribute to the quality, nutrition, and toxicity of these systems. In this work, we develop a material flow model to deal primarily with the water phase (water quality modeling) while including pertinent information on the solid and air phases as they interface with the water medium. Both spatial and temporal dimensions are included to account for nitrogen flow and transformation. The model includes the various environmental phenomena that influence the fate and transport of targeted species (e.g., volatilization, precipitation, sedimentation, uptake by biota, adsorption, chemical and biochemical reactions, etc.). Interactions between phosphorus and nitrogen compounds are accounted for in analysis and integration of solution strategies. The aforementioned analysis tools are combined in a computer-aided modeling platform to provide a complete material flow analysis and yield useful insights on the transport and fate of targeted species. Next, mass integration techniques are employed to aid in the development for phosphorus and nitrogen-management strategies. The problem of minimizing negative environmental impact subject to technical, social, economic, and regulatory constraints is posed as a mixed integer nonlinear program whose solution identifies and synthesizes the most effective solution strategies.