6/06/2017  |   09:00 - 09:15   |  301B

Overview of Constructed Wetlands This presentation will be a brief overview of man-made (constructed) wetland ecosystems, with an emphasis on how wetland ecosystem services are being utilized to meet specific regulatory goals.

Scott Wallace (Primary Presenter/Author), Naturally Wallace Consulting, scott.wallace@naturallywallace.com;


Presentation:
This presentation has not yet been uploaded.

6/06/2017  |   09:15 - 09:30   |  301B

Feast or famine: The challenge of nitrogen removal in treatment wetlands Constructed wetlands have been used since the 1950s to reduce biochemical oxygen demand (BOD) and total suspended solids (TSS) concentrations in wastewater. However, with the increased occurrence of harmful algal blooms and hypoxia in lakes and coastal waters, cost-effective methods for nutrient removal are needed. Phosphorus removal is largely due to sorption and particulate settling; thus, designing wetlands to remove phosphorus is relatively straight-forward. In comparison, the main removal pathway for nitrogen is by conversion of organic nitrogen to inorganic nitrogen and then to dinitrogen gas via denitrification. Because each of these processes is mediated primarily by microorganisms, understanding microbial ecology is critical to designing treatment wetlands to remove nitrogen. Development of such a treatment train in a wetland system requires balancing the necessary supplies of electron donors and electron acceptors for each type of microorganism while also providing the proper redox conditions for the growth of both aerobes and anaerobes. This presentation illustrates the challenge of achieving high levels of nitrogen removal using constructed wetlands.

Tess Thompson (Primary Presenter/Author), Virginia Tech, tthompson@vt.edu;


Presentation:
This presentation has not yet been uploaded.

6/06/2017  |   09:30 - 09:45   |  301B

CAN WE USE WETLANDS TO TREAT PULSES OF NUTRIENTS FROM AGRICULTURAL WATERSHEDS? Agricultural production has been identified as a major source of nutrients contributing to the eutrophication of aquatic ecosystems throughout the world. Among the practices implemented to reduce the mass of nutrients reaching sensitive water bodies is directing agricultural runoff or drainage through wetlands. The natural biogeochemial processes that occur in wetlands appear to make them an ideal treatment system for excess nutrients. The wetlands used for the treatment of agricultural non-point source pollution can take multiple forms, including restored wetlands or wetlands built solely for treatment. Nutrient export from row crop agriculture generally occurs in pulses that is driven by rainfall events. These short periods of high nutrient flux are different from the nutrient dynamics found in other treatment wetlands that operate closer to a steady state. For wetlands to be effective sinks for nutrients from agricultural production, the processes that retain nutrients must be capable of reacting quickly to the arrival of a pulse of nutrients. This presentation will examine the effectiveness of wetlands to remove nutrients in agricultural watersheds.

Randall Etheridge (Primary Presenter/Author), East Carolina University, etheridgej15@ecu.edu;


Presentation:
This presentation has not yet been uploaded.

6/06/2017  |   09:45 - 10:00   |  301B

CONSTRUCTED WETLAND TREATMENT SYSTEMS – PUTTING WETLAND BIOGEOCHEMISTRY TO WORK Wetlands are aquatic systems that host unique biogeochemical reactions used in constructed wetland treatment systems (CWTSs) to treat (transfer and transform) elements and compounds in industrial waters to mitigate risks. This presentation includes two case studies to illustrate process-based design of CWTSs. The A-01 CWTS at the Department of Energy’s Savannah River Site was designed to treat metals (e.g. copper, zinc, and mercury) in stormwater runoff and industrial process water. Operating for more than 15 years, this CWTS has and continues to perform as designed. In another study, wetlands were designed to treat large volumes of oil sands process-affected water (OSPW) from the Athabasca oil sands near Ft. McMurray (Alberta, Canada). A hybrid pilot-scale CWTS was designed to promote treatment processes for metals (e.g. Al, Cu, Ni, and Zn) and naphthenic acids (NAs) using sequential reducing and oxidizing wetland reactors and a solar photocatalytic reactor using fixed-film titanium dioxide. Results from this study provide proof-of-concept data to inform hybrid passive or semi-passive treatment approaches (i.e. constructed wetlands) that will be used to mitigate targeted constituents in OSPWs.

John Rodgers (Primary Presenter/Author), Clemson University, jrodger@clemson.edu;


Andrew McQueen ( Co-Presenter/Co-Author), Clemson University, andrew.d.mcqueen@gmail.com;


Maas Hendrikse ( Co-Presenter/Co-Author), Clemson University, maash@g.clemson.edu;


Presentation:
This presentation has not yet been uploaded.

6/06/2017  |   10:00 - 10:15   |  301B

Enhanced Photodegradation of Contaminants of Emerging Concern in Constructed Wetlands Contaminants of emerging concern (CECs) are wastewater derived trace organic compounds such as pharmaceuticals, personal care products, and endocrine disrupting compounds. CECs in surface waters even at low concentrations may lead to long term human health risks and harm the aquatic environment. These compounds are not completely attenuated by conventional biological treatment processes and the cost of removal via advanced treatment is high. Constructed wetlands offer a sustainable alternative for the removal of CECs. Specifically, the direct and indirect photodegradation of CECs has shown promise as a significant mechanism for CEC degradation. Our research group is particularly interested in the indirect photodegradation of contaminants of emerging concern. Indirect photodegradation entails the oxidation of contaminants through the generation of reactive oxygenated species. These reactive species are readily generated through the interaction of sunlight and chromophoric dissolved organic matter. In this presentation we will describe ongoing research at NC State to characterize existing photodegradation capacity in constructed wetlands and develop new insights into the effective design of constructed wetlands to enhance photochemical degradation of contaminants of emerging concern.

Tarek Aziz (Primary Presenter/Author), NC State University, tnaziz@ncsu.edu;


Barbara Cottrell ( Co-Presenter/Co-Author), University of California Irvine, bcottrel@uci.edu;


Arpit Sardana ( Co-Presenter/Co-Author), NC State University, asardan@ncsu.edu;


Presentation:
This presentation has not yet been uploaded.

6/06/2017  |   10:15 - 10:30   |  301B

STRATEGIC EXPANSION OF CONSTRUCTED WETLANDS TO TREAT RURAL WASTEWATER CAN ACCELERATE IMPROVEMENTS IN WATERSHED HEALTH Despite dedicated efforts, pollutant reduction goals have not been achieved in many watersheds. Other target pollutant sources and treatment methods should be identified to accelerate these efforts. Research has demonstrated that constructed wetlands can reduce many pollutants that commonly degrade watershed health; however, the use of these systems is not widespread in many regions. Strategic location of constructed wetlands seems a viable alternative to provide additional treatment to rural wastewater, an often ignored pollutant source. For example, small package wastewater plants, often numerous across rural watersheds, often treat ammonium efficiently but discharge significant amounts of unregulated nitrate, a key contributor to eutrophication. Small constructed wetlands could be installed to intercept and denitrify a significant amount of nitrate before it reaches surface water. A recent survey in NC revealed that of the thousands of permitted package plants and rural wastewater facilities, only six constructed wetlands (sized between 0.4 – 17 ha) provided some level of secondary or tertiary treatment. Despite their promise, many factors must be overcome to realize the full benefits low-cost constructed wetlands can provide to these watersheds.

Michael Burchell (Primary Presenter/Author), NC State University, mike_burchell@ncsu.edu;


Presentation:
This presentation has not yet been uploaded.