This report is the culmination of a 3-year research project titled, "Aqueous pollutant capture by enhanced filter media," which was funded by the Minnesota Pollution Control Agency through its Federal Clean Water Act Section 319 (Section 319) grant program, with Gregory Johnson as project manager. The purpose of this project was to research materials that could be used in new or renovated sand filters, infiltration systems, rain gardens, and buffer strips to capture significant amounts of dissolved heavy metals, phosphorus, and nitrogen that are typically found in urban and agricultural runoff. This was accomplished with five primary objectives, which have been organized into five representative Chapters that are described below. Chapter 1 consists of an extensive literature review that was used to not only inform and guide the project, but also to satisfy the first objective (Objective 1: Literature review and agent section). Through this literature review, enhancing materials were evaluated and some were selected for testing as part of this project. In addition, this literature prevented duplication of previous research efforts. The review incorporated performance by existing stormwater treatment practices for water quantity reduction and capture of dissolved heavy metals, phosphorous, and nitrogen and also investigated potential enhancements that capture dissolved heavy metals, phosphorus, and nitrogen. Chapter 2 discusses batch studies that were performed on enhancing materials selected in Chapter 1, which satisfies the second objective (Objective 2: Perform batch studies and agent selection). Batch studies involved mixing enhancing materials with synthetic stormwater laden with stormwater pollutants of concern: metals, phosphorus, and nitrogen. By collecting samples and measuring change in concentration, the sorption capacity of the enhancing materials was determined and compared for well-mixed conditions. From this comparison, several materials were selected to further investigation. Chapter 3 discusses column studies that were performed on a few enhancing materials selected from the literature review and batch studies, which satisfies the third objective (Objective 3. Perform column studies and develop descriptive models). Synthetic stormwater was added to these columns while samples were collected samples and flow rate was measured and controlled. Sorption capacity for flow-through conditions was estimated from the data collected. The Thomas model (Thomas 1948) is a well-known model in the chemistry field that describes breakthrough of pollutants in flow-through columns. When fit to the data collected in this project, the Thomas model was found to adequately describe the removal of pollutants by the enhancing materials selected. Chapter 4 discusses field verification studies that were performed on two enhancing materials, which satisfies the fourth objective (Objective 4. Field verification studies). River water was collected in lieu of natural stormwater and passed through a scaled enhanced media filter. The water was tested and supplemented as necessary to represent the target conditions for the experiment. Samples were collected and flow rate was measured to determine the sorption capacity that could be expected of the enhancing materials in a field application. Again, the Thomas model was fit to the data and found to adequately describe the removal of pollutants by the enhancing materials. Chapter 5 provides a summary of the project results and associated conclusions, which in addition to activities throughout the project, satisfies the fifth and final objective (Objective 5. Public Outreach/Public Participation and Deliverables).
|Original language||English (US)|
|State||Published - Sep 2014|