19 Mar 2025

Peptide Display for Rare Earth Element Binding

Abstract: Rare earth elements (REEs) are metals that are indispensable to the function of many advanced systems and materials. The supply chain of REEs is heavily dependent on foreign sources and supply shortages are a major concern to the US government. Biological recovery approaches could be an economically feasible approach to recover REEs from unconventional or secondary sources. The objective of this project was to express a lanthanide-binding tag, with an affinity for adsorption of REEs, on the surface of the biomining bacterium, Acidithiobacillus ferrooxidans. This was to be accomplished using synthetic biology tools. The initial cloning steps were performed in Escherichia coli, since techniques are well established in this strain. Using a peptide display approach, several DNA constructs with the binding tag were designed that were regulated by constitutive or inducible promoters and cloned into plasmids that replicate in E. coli and A. ferrooxidans. All plasmids were observed to be unstable or lethal in E. coli, exhibiting sequence rearrangements or deletion of the designed construct. Conjugation between E. coli and A. ferrooxidans and subsequent REE binding assays were thus not possible due to the absence of a structurally and functionally intact plasmid.

12 Mar 2025

Collaborative Development of Natural and Nature-Based Solutions for Coastal Resiliency in the Arctic and Adjacent Regions: A Workshop

The workshop “Collaborative Development of Natural and Nature-Based Solutions for Coastal Resiliency in the Arctic and Adjacent Regions” was held in Reston, Virginia, October 24–25, 2023. The objective was to assemble diverse international partners in a hybrid in-person and virtual setting to focus on the viability of applying Nature-Based Solutions (NBS) to solve engineering challenges in the Arctic and similar cold region locations. The goals of the two-day workshop were to share recent efforts implementing NBS to mitigate coastal hazards such as flooding and erosion in northern high latitude settings and identify requirements and develop a robust program of activities to advance this work at national, regional, and local levels. This workshop report documents the presentations and discussion and summarizes key needs and recommendations for future engagement identified by speakers and workshop participants.

7 Mar 2025

Coupling Electrokinetics and Phytoremediation to Remove Uranium from Contaminated Soil: A Laboratory Pilot-Scale Study

Abstract: Uranium is a naturally occurring trace element and radionuclide. Uranium is introduced to the environment anthropogenically because of industrial, military, and nuclear energy activities. The approach of coupled electrokinetic phytoremediation has been used to remove other heavy metals from contaminated soil. The objectives here are to investigate the distribution and solubility of uranium in soils with UO2, UO, and uranyl, and examine the processes of coupled electrokinetic phytoremediation in removing U from soils with perennial ryegrass at a laboratory pilot scale. A low-intensity direct electric current field was applied to the contaminated soil for 7 d at 8 h·d−1 after ryegrass was grown for 2 weeks, then, polarity reversal was employed for another 7 d at 8 h·d−1. The uranium redistribution took place among various solid-phase components due to changes in the pH and chemistry of the electrolyte solution. The electrokinetic field increased the U bioavailability in soils as water-soluble U and exchangeable U in contaminated soils with all U species. Thus, the EKF significantly increased the U uptake and bioaccumulation by ryegrass. The current laboratory pilot-scale test confirmed our previous observation from the pot greenhouse study–the coupled electrokinetic phytoremediation may have potential for application in remediating U-contaminated sites.

26 Feb 2025

Demonstration of Photocatalytic Degradation of Per- and Polyfluoroalkyl Substances (PFAS) in Landfill Leachate Using 3D Printed TiO2 Composite Tiles

Abstract: Per- and polyfluoroalkyl substances (PFAS) are recalcitrant substances present globally in many landfill wastewater leachates and have potential ecological and human health risks. Conventional treatment technologies have shown limited efficacy for many PFAS due to the stable C–F bonds. Therefore, there is growing interest in applying advanced oxidation processes to decrease the aqueous concentrations in contaminated wastewater and mitigate risks. The goal of this study was to evaluate the photocatalytic performance of treating PFAS in landfill leachate using a novel photocatalyst composite. Treatment structures were fabricated using polylactic acid and compounded with TiO2, and 3D printed into tiles. A pilot-scale treatment system was designed to promote photocatalysis using 3D composite structures and UV irradiance intensity of 1.0 mW cm−2 following 24- and 36-h hydraulic retention times. Photocatalytic degradation was achieved for seven of the 11 PFAS evaluated in this study. Greater than 80% removal of PFOS, PFNA, PFDA, and PFOSAm was observed after 24 h of photocatalysis. These results indicate photocatalysis using TiO2 polymer composites can achieve beneficial levels of PFAS degradation. This study provides a proof-of-principle approach to inform the application of additive manufacturing of photocatalytic composites for use in the treatment of PFAS-contaminated wastewater.

19 Feb 2025

Autonomous Cyberdefense Introduces Risk; Can We Manage the Risk?

Abstract: We discuss the human role in the design and control of cyberdefenses. We focus on machine learning training and algorithmic feedback and constraints, with the aim of motivating a discussion on achieving trust in autonomous cyberdefenses.

19 Feb 2025

Lower James River Sediment Transport Modeling: Jordan Point

Abstract: US Army Corps of Engineers–Norfolk District (NAO) requested assistance from the US Army Engineer Research and Development Center (ERDC) to examine currently used placement sites within the James River, Virginia, initiative area, determine potential risk to critical environmental receptors during placement, and predict the life cycle of the placement sites. The focus of the analysis within this work is the Jordan Point placement site. The far-field, fate-transport modeling at Jordan Point shows relatively low maximum values of suspended sediment concentration (less than 40 mg/L) and deposition values (less than 0.2 cm). Material that is placed at Jordan Point appears to quickly disperse through the system, depositing in thin layers at specific areas. The life-cycle analysis performed for the Jordon Point placement site yielded an estimated useable project life of the Jordan Point placement sites of 26 years with an uncertainty of ±4 years. Analysis showed that 97% of the net sediment deposition in the navigation channel in proximity to this site is from the upper James River, 2% is from downstream sources, and 1% is from the two Jordan Point placement sites.

19 Feb 2025

Exploring the Convergence of Resilience Processes and Sustainable Outcomes in Post-COVID, Post-Glasgow Economies

Abstract: Resilience and sustainability have each offered a path forward for post-COVID economic recovery and a post-Glasgow global financial order. Yet, the relationships between these two concepts are largely unexplored in economic policy and investment strategies. In light of emerging systemic risks and global demands for more resolute investments in resilience and sustainability, this perspective article took the position that policymakers must begin to draw greater conceptual, empirical, and practical linkages between sustainability and resilience. This perspective article provided a simplified framework for understanding the positively reinforcing, negatively conflicting, and neutral relationships between different types of resilience and sustainability consistent with two propositions. The Reinforcement Proposition argues (i) that various resilience processes may drive sustainable outcomes, and/or (ii) that an allocation of sustainable resources may reinforce resilience processes, as well as the transformative adaptation of markets. Conversely, the Conflict Proposition argues (i) that certain resilience processes may perpetuate stability features that may thwart an economic transition toward sustainability, and/or (ii) that certain sustainability outcomes associated with reorganized economic structures and relationships may undermine resources for resilience. This framework provides policymakers with an opportunity to evaluate the convergent and conflicting trade-offs of resilience processes and sustainable outcomes.

4 Feb 2025

Beneficial Use of Dredged Material for Submerged Aquatic Vegetation Habitats: Overcoming Challenges and Seeking New Opportunities

Purpose: There is a critical need to maintain and create conditions that are conducive for long-term survival of submerged aquatic vegetation (SAV) habitats, which provide multiple ecosystem services, using dredged material. This technical note (TN) was developed by the US Army Engineer Research and Development Center (ERDC)–Environmental Laboratory (EL) to address the specific challenges US Army Corps of Engineers (USACE) practitioners at the district and division level face that impede the development of beneficial use of dredged material (BUDM) projects to restore, conserve, and expand SAV habitats. Different ways to overcome these challenges and opportunities that should be further explored are also addressed. The information in this TN was synthesized from discussions at a virtual workshop for USACE practitioners.

3 Feb 2025

Notes on Bedload Sediment Collector Deployment: Eau Claire River, Wisconsin

Purpose: A bedload sediment collector field deployment was conducted during low flow conditions from August 2023 to September 2023 on the Eau Claire River, Wisconsin, to assess the operation and performance of a 12 ft bedload sediment collector (BSC). This initial deployment of the technology served to familiarize the research team with the new 12 ft BSC system in preparation for its potential deployment during high flow conditions and at other locations. The insights from this study are intended to identify opportunities to use this technology, particularly in the Upper Mississippi River navigation system.

3 Feb 2025

Mediated Model Development for Coastal Marsh Management in the Chesapeake Bay

Purpose: The purpose of this technical note is to develop a conceptual model that describes the critical processes, stressors, and interactions that affect coastal marsh dynamics within the Chesapeake Bay, as identified by subject matter experts, and then link those factors to specific management actions. Managing coastal marshes within Chesapeake Bay involves multiple stakeholders across federal, state, local, and nongovernmental agencies. Reaching consensus among large stakeholder groups can be difficult, since each has their own perspective and requirements for management. Mediated modeling is a technique that facilitates consensus building among stakeholders and provides a transparent roadmap for decision-making. This technical note describes how mediated modeling was applied to marsh management in Chesapeake Bay. On 4–5 May 2022, The Nature Conservancy (TNC) and the US Army Engineer Research and Development Center (ERDC) Integrated Ecological Modeling Team (EcoMod) partnered for a multistakeholder mediated modeling workshop to (1) build a conceptual model that depicts the relevant processes impacting marsh dynamics, and (2) identify indicators that are necessary for tracking marsh conditions, which inform needed management strategies. This conceptual model provides the foundation for the development of a marsh management decision framework that will use indicators to identify marsh conditions that subsequently trigger management decisions.