Treatment wetlands

Through the Horizontal Levee, we aim to study the efficacy of subsurface constructed wetlands for treating wastewater effluent at the Oro Loma Sanitary District. In addition, we began transitioning the influent of one of wetland’s cells from wastewater to reverse osmosis concentrate to study how the Horizontal Levee responds to influent changes. Removal mechanisms for a diverse array of contaminants (e.g. nutrients, trace organics, metals) are being studied in this system, with hopes of determining whether these natural treatment systems are capable of decreasing the concentration of contaminants traditionally difficult to remove in wastewater. Dominant removal mechanisms displayed so far within the Horizontal Levee include adsorption, (co-)precipitation, biotransformation, and plant uptake, and we are interested in determining how the behavior of each potential sink changes with time. Through this, we may develop an understanding of the expected performance and lifetime of future constructed wetlands for wastewater and other water treatment applications.

1. Scholes, R. C.; Stiegler, A. N.; Anderson, C. M.; Sedlak, D. L. Enabling Water Reuse by Treatment of Reverse Osmosis Concentrate: The Promise of Constructed Wetlands. ACS Environmental Au 2021, XXXX, XXX, XXX−XXX.
2. Scholes, R. C.; King, J. F.; Mitch, W. A.; Sedlak, D. L. Transformation of Trace Organic Contaminants from Reverse Osmosis Concentrate by Open-Water Unit-Process Wetlands with and without Ozone Pretreatment. Environmental Science & Technology 2020, 54, 24, 16176–16185.
3. Cecchetti, A. R.; Systema, A.; Stiegler, A. N.; Dawson, T. E.; Sedlak, D. L. Use of stable nitrogen isotopes to track plant uptake of nitrogen in a nature-based treatment system. Water Research X 2020, 9, 100070.
4. Cecchetti, A. R.; Stiegler, A. N.; Graham, K.; Sedlak, D. L. The Horizontal Levee: A Multi-Benefit Nature-Based Treatment System That Improves Water Quality And Protects Coastal Levees From The Effects Of Sea Level Rise. Water Research X 2020, 7, 100052.
5. Scholes, R. C.; Prasse, C.; Sedlak, D. L. The Role Of Reactive Nitrogen Species In Sensitized Photolysis Of Wastewater-Derived Trace Organic Contaminants. Environmental Science & Technology 2019, 53 (11), 6483-6491.
6. Bear, S.; Nguyen, M.; Jasper, J.; Nygren, S.; Nelson, K.; Sedlak, D. Removal Of Nutrients, Trace Organic Contaminants, And Bacterial Indicator Organisms In A Demonstration-Scale Unit Process Open-Water Treatment Wetland. Ecological Engineering 2017, 109, 76-83.