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  • Photocatalytic Degradation of Microcystins from a Field-Collected Cyanobacterial Assemblage by 3D Printed TiO2 Structures Using Artificial Versus Solar Irradiation

    Abstract: Microcystins from freshwater cyanobacteria cause adverse effects to humans and ecological receptors through multiple exposure routes requiring adaptable and diverse treatment technologies. Photocatalysis of MCs using TiO2 is a promising technology; however, TiO2 photocatalysts as unbound nanoparticles in suspension are impractical to deploy. 3D Printing provides a means to immobilize TiO2, producing deployable photo-catalyst structures with extensive geometric freedom. The objective of this proof-of-concept experiment was to incrementally increase the environmental complexity while comparing photocatalysis rates of MCs by 3DP TiO2 structures using polylactic acid as the binder. Degradation half-lives of MCs were shorter in TiO2 embedded in 3DP PLA relative to PLA-only controls with differences in half-lives ranging from 3.6 to 10h. The one exception was the outdoor solar and an algal assemblage, where significant differences could not be discerned due to the already rapid photolysis rates. Ultimately, photocatalysis rates were comparable to those previously published for TiO2 3DP structures in a laboratory environment and TiO2 fixed- films demonstrating feasibility of 3DP to immobilize TiO2 photocatalysts under a range of conditions. This is the first time that MC concentrations from a field-collected HAB were photocatalytically degraded in both solar simulated light and sunlight using a custom-made advanced photocatalytic nano- composite with enhanced performance through high surface area design enabled by 3D printing. These data inform future development of scalable, retrievable, and operationally flexible structures with immobilized TiO2.
  • Investigation of Graphene Nanoplatelets for Adsorptive Removal of Aqueous Munitions Compounds 2,4,6-Trinitrotoluene (TNT) and Hexahydro-1,3,5-Trinitro-S-Triazine (RDX)

    Abstract: Graphene nanoplatelets (GnPs) were evaluated against munitions compounds 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-s-triazine (RDX) in aqueous solutions for adsorptive removal performance. Fourier transform infrared and Raman spectroscopy were employed to characterize samples and inform adsorption mechanisms. Adsorption kinetics and isotherm studies were conducted in deionized water and compared with granular activated carbon (GAC). Evaluations were conducted with varying pH levels, ionic strengths, and temperatures and with surface water solutions to assess the impact of environmental factors on performance and further inform adsorption mechanisms. This study demonstrated that GnPs exhibited more rapid adsorption than GAC. Furthermore, TNT was adsorbed with greater capacity by GnPs compared to GAC, while GnPs removed RDX in greater capacity only when results were normalized for surface area. The more planar structure of GnPs may have contributed to performance enhancements relative to GAC. Adsorption was not impacted by variations in pH or ionic strength, indicating stable performance in different environments. Thermodynamic analysis indicated that removal was more favorable at higher temperatures. Furthermore, π-π interactions likely facilitated TNT removal by GnPs, while RDX was removed through physisorption by van der Waals forces. This study advanced understanding of environmental management of munitions compounds, as the adsorptive performance of GnPs for munitions compounds in solutions within a natural environmental matrix were evaluated, and key mechanisms supporting adsorptive removal of these compounds were informed. Overall, this study demonstrated the effectiveness of GnPs in treating water contaminated with TNT or RDX, particularly when rapid adsorption is preferred.
  • 23-037 Corps to treat Lake Wallula to control invasive flowering rush

    WALLA WALLA, WA– The U.S. Army Corps of Engineers Walla Walla District will be performing up to five five-acre treatments in Lake Wallula, the McNary reservoir near the Tri-Cities, Washington, with herbicide, Diquat Dibromide, at an application rate of two gallons per surface acre. This effort is to control the invasive aquatic plant species flowering rush.
  • 22-056 Corps to treat Lake Wallula to control invasive flowering rush

    KENNEWICK, Wash.– The U.S. Army Corps of Engineers’ Walla Walla District will be performing up to eight five-acre treatments in Lake Wallula, the McNary reservoir near Tri-Cities, Washington, with herbicide, Diquat Dibromide, at an application rate of two gallons per surface acre. This effort is to control the invasive aquatic plant species flowering rush.
  • Pittsburgh District and city of Paden City partner for $2 million project

    The U.S. Army Corps of Engineers Pittsburgh District entered a partnership agreement with the city of Paden City, West Virginia, to upgrade sanitary sewer collection and treatment facilities as part of a $2 million Section 219 Environmental Infrastructure project, Thursday, Jan. 6.
  • East Brimfield Lake waters closed to the public on Aug. 17 for 24 hours

     The U.S. Army Corps of Engineers (USACE), New England District announced today that the waters at
  • Corps Signs Partnership Agreement for Water Treatment Plant Upgrades

    The U.S. Army Corps of Engineers Pittsburgh District has entered into a more than $3.3-million project partnership agreement with the city of Chester to complete upgrades to the city’s water treatment plant.
  • ERDC reports Chautauqua Lake HABITATS research results

    Researchers from the U.S. Army Engineer Research and Development Center (ERDC), in collaboration with New York State Department of Environmental Conservation (NYSDEC) scientists and industry partners, concluded the field demonstration portion of their research project to study harmful algal bloom (HAB) mitigation technology Sept. 4 in Chautauqua Lake, New York.
  • ERDC, New York State research algal bloom mitigation in Chautauqua Lake

    Researchers from the U.S. Army Engineer Research and Development Center (ERDC) and scientists from New York State Department of Environmental Conservation (NYSDEC) are collaborating with industry partners to study harmful algal bloom (HAB) mitigation technology in Chautauqua Lake, New York, from Aug. 19 through Sept. 4.
  • ERDC overcomes challenges in harmful algal bloom removal research

    The U.S. Army Engineer Research and Development Center (ERDC) continued its quest to tackle the challenging problem of harmful algal blooms (HABs) in our nation’s waterways with a removal demonstration in Florida in July 2020. The ERDC research team and collaborators from engineering firm AECOM and the University of Illinois planned and executed the research study on HAB removal at Lake Okeechobee.