Design and Construction of Phosphorus Removal Structures for Improving Water Quality

1. Introduction to phosphorus and water quality 1.1. The role of phosphorus in ecosystems 1.1.1. Eutrophication 1.1.2. Cultural and Political Response to Eutrophication Issues 1.2. Sources of phosphorus transported to surface waters 1.2.1. Point Sources (Wastewater Treatment Plants) 1.2.2. Non-point phosphorus sources and forms 1.3. Best management practices and dissolved phosphorus losses 1.4. References 2. Reducing Phosphorus Transport: An Overview of Best Management Practices 2.1. Dealing with eutrophication: treat the symptoms or the cause? 2.2. Incidental vs. legacy phosphorus losses 2.3. Legacy phosphorus 2.3.1. Preventing legacy P from occurring 2.3.2. Containment of legacy phosphorus losses 2.3.3. Remediation of legacy phosphorus 2.4. References 3. Phosphorus Removal Structures as a Short-Term Solution for the Problem of Dissolved Phosphorus Transport to Surface Waters 3.1. Purpose, Concept, and General Theory of Phosphorus Removal Structures 3.1.1. How the phosphorus removal structure works for removing the target pollutant: dissolved phosphorus 3.1.2. Choosing the most efficient target locations for a phosphorus removal structure 3.2. Examples and applications of phosphorus removal structures 3.2.1. Modular box 3.2.2. Ditch-filter 3.2.3. Surface confined bed 3.2.4. Cartridges 3.2.5. Pond filter 3.2.6. Blind/surface inlets 3.2.7. Bio-retention cell 3.2.8. Subsurface tile drain filter 3.2.9. Waste-water treatment structures 3.2.10. Treatment at confined animal feeding operations 3.2.11. Treatment at silage bunkers 3.3. Summary of P removal structure styles 3.4. References 4. Phosphorus sorption materials (PSMs): the heart of the phosphorus removal structure 4.1. What are PSMs? 4.1.1.< Examples of PSMs 4.1.2. Choosing a PSM 4.2. What makes a material an effective PSM? 4.2.1. P sorption capacity and kinetics of P removal 4.2.2. Physical properties important to PSMs 4.2.3. Safety considerations of PSMs 4.3. The paradox of many PSMs 4.3.1. Potential solutions for PSMs with insufficient hydraulic conductivity 4.3.2. A note on the use of steel slag and chemical treatment 4.4. References 5. Characterization of PSMs 5.1. Measuring and estimating P removal: flow-through vs. batch tests 5.2. The P removal design curve 5.2.1. Method for direct measurement of the design curve: flow-through experiment 5.2.2. Indirect estimation of the P design curve through characterization of PSMs 5.3. Methods of physical characterization of PSMs necessary for designing a P removal structure 5.3.1. Measurement of bulk density 5.3.2. Measurement of porosity and particle density 5.3.3. Measurement of saturated hydraulic conductivity 5.4. Methods of safety characterization of PSMs 5.4.1. Total metal concentration by digestion 5.4.2. Method for water soluble metals 5.4.3. Synthetic precipitation leaching procedure (SPLP) 5.5. References 6. Designing a Phosphorus Removal Structure 6.1. Designing structures to achieve target P load removal and lifetime 6.1.1. Use of the design curve and governing equations for designing structures 6.1.2. Determining the required mass of PSM for a P removal structure 6.2. Site characterization inputs required for conducting a design 6.2.1. Average annual dissolved P load 6.2.2. Peak flow rates 6.2.3. Hydraulic head and maximum area for structure 6.3. Drainage of the P removal structure: balancing flow rate with retention time 6.3.1. Water flow through the P removal structure 6.3.2. Retention time 6.3.3. Drainage of the P removal structure 6.4. General procedure for conducting a structure design and information obtained 6.4.1. General design procedure 6.4.2. General results from conducting a proper design 6.5. Optional: total and particulate P removal with sediment reduction 6.5.1. Estimating sediment load reduction 6.5.2. Estimating total P and particulate P reductions from sediment removal within the structure 6.6. Further considerations in design and construction 6.6.1. Free drainage 6.6.2. Using a "cap layer" for fine-textured PSMs 6.6.3. Use of flow control structures 6.6.4. Overflow 6.7. References 7. Using the Phrog software 7.1. Designing a P removal structure vs. predicting performance of an existing structure 7.2. Two broad styles for P removal structures: bed vs. ditch structure 7.3. Specific inputs required for design of a P removal structure 7.3.1. Chemical and physical characteristics of PSM to be used 7.3.2. Site characteristics, constraints, and target P removal goals 7.3.3. Additional inputs for predicting performance of an existing structure 7.3.4. Optional inputs for estimating total and particulate P removal 7.4. General output from Phrog software when conducting a design 7.4.1. Output: physical construction specifications 7.4.2. Output: predicted structure performance and guidance in obtaining a suitable design 7.5. Case studies using Phrog to design or predict 7.5.1. Design a ditch structure: details of Phrog use and example of how to simultaneously meet the target flow rate and retention time 7.5.2. Predict performance of an existing ditch structure 7.5.3. Design a subsurface bed structure for treating tile drainage 7.5.4. Predict the performance of a blind inlet and demonstration of predicting particulate and total P removal 7.5.5. Bio-retention cells 7.5.6. Design a confined bed located on a CAFO 7.5.7. Wastewater treatment plant tertiary P treatment and example use of direct input of design curve coefficients 7.6. References 8. Disposal of Spent Phosphorus Sorption Materials 8.1. Use of spent PSMs as a P fertilizer 8.1.1. Testing PSMs to determine potential for P release to plants or runoff after land application to soil 8.2. Extraction of P from spent PSMs and potential recharge 8.2.1. Stripping P from spent PSMs: is it worth it? 8.3. Land application of spent PSMs to soils for benefits other than P fertilizer 8.3.1. Safety considerations in land application of spent PSMs 8.4. Alternative to land application of spent PSMs 8.5. 8.5 References