The Environmental Protection Agency (EPA) provides access to information on a variety of topics related to the environment and strives to inform citizens of health risks. The EPA also has an extensive library network that consists of 26 libraries throughout the United States, which provide access to a plethora of information to EPA employees, scientists, and researchers. The EPA implemented a reorganization project to digitize their materials so they would be more accessible to a wider range of users, but this plan was drastically accelerated when the EPA was threatened with a budget cut. It chose to close and reduce the hours and services of some of their libraries. As a result, the agency was accused of denying users the “right to know” by making information unavailable, not providing an adequate strategic plan, and discarding vital materials. This case study explores the background of the digitization project, the practices implemented, and the critiques of the project.

/pdf/the-environmental-protection-agency-3gx4opzrjm.pdf

The Environmental Protection Agency

Electrochemical processes have been extensively investigated for the removal of a range of organic and inorganic contaminants. The great majority of these studies were conducted using nitrate-, perchlorate-, sulfate-, and chloride-based electrolyte solutions. In actual treatment applications, organic and inorganic constituents may have substantial effects on the performance of electrochemical treatment. In particular, the outcome of electrochemical oxidation will depend on the concentration of chloride and bromide. Formation of chlorate, perchlorate, chlorinated, and brominated organics may compromise the quality of the treated effluent. A critical review of recent research identifies future opportunities and research needed to overcome major challenges that currently limit the application of electrochemical water treatment systems for industrial and municipal water and wastewater treatment. Given the increasing interest in decentralized wastewater treatment, applications of electrolytic systems for treat...

Challenges and Opportunities for Electrochemical Processes as Next-Generation Technologies for the Treatment of Contaminated Water

Energy-efficient desalination and water treatment technologies play a critical role in augmenting freshwater resources without placing an excessive strain on limited energy supplies. By desalinating high-salinity waters using low-grade or waste heat, membrane distillation (MD) has the potential to increase sustainable water production, a key facet of the water-energy nexus. However, despite advances in membrane technology and the development of novel process configurations, the viability of MD as an energy-efficient desalination process remains uncertain. In this review, we examine the key challenges facing MD and explore the opportunities for improving MD membranes and system design. We begin by exploring how the energy efficiency of MD is limited by the thermal separation of water and dissolved solutes. We then assess the performance of MD relative to other desalination processes, including reverse osmosis and multi-effect distillation, comparing various metrics including energy efficiency, energy quality, and susceptibility to fouling. By analyzing the impact of membrane properties on the energy efficiency of an MD desalination system, we demonstrate the importance of maximizing porosity and optimizing thickness to minimize energy consumption. We also show how ineffective heat recovery and temperature polarization can limit the energetic performance of MD and how novel process variants seek to reduce these inefficiencies. Fouling, scaling, and wetting can have a significant detrimental impact on MD performance. We outline how novel membrane designs with special surface wettability and process-based fouling control strategies may bolster membrane and process robustness. Finally, we explore applications where MD may be able to outperform established desalination technologies, increasing water production without consuming large amounts of electrical or high-grade thermal energy. We conclude by discussing the outlook for MD desalination, highlighting challenges and key areas for future research and development.

https://par.nsf.gov/servlets/purl/10058665

Membrane distillation at the water-energy nexus: limits, opportunities, and challenges

https://cronfa.swan.ac.uk/Record/cronfa48864/Download/0048864-07032019141310.pdf

Reverse osmosis desalination: A state-of-the-art review

Aquatic surface chemistry: Edited by Werner Stumm. Wiley, New York. 1987. $69.95 (ISBN 0471822951)

Recent revision of the arsenic in drinking water standard will cause many utilities to implement removal technologies. Most of the affected utilities are expected to use adsorption onto solid media for arsenic removal. The arsenic-bearing solid residuals (ABSR) from adsorption processes are to be disposed of in nonhazardous landfills. The Toxicity Characteristic Leaching Procedure (TCLP) tests whether a waste is hazardous or nonhazardous; most solid residuals pass the TCLP. However, the TCLP poorly simulates the alkaline pH, low redox potential, biological activity, long retention time, and organic composition of mature landfills. These same conditions are likely to favor mobilization of arsenic from metal oxide sorbents. This study quantifies leaching of arsenic from Activated Alumina (AA) and Granular Ferric Hydroxide (GFH), two sorbents expected to be widely used for arsenic removal. The sorbents were subjected to the TCLP, the Waste Extraction Test (WET), an actual landfill leachate, and two synthetic...

https://www.niehs.nih.gov/news/assets/docs_p_z/tclp_underestimates_leaching_of_arsenic_from_solid_residuals_under_landfill_conditions_508.pdf

TCLP underestimates leaching of arsenic from solid residuals under landfill conditions.

A review of irregular time series data handling with gated recurrent neural networks

Effect of pH, competitive anions and NOM on the leaching of arsenic from solid residuals

https://repository.arizona.edu/bitstream/10150/633296/1/Effect_of_silicic_acid_on_arsenate_and_arsenite_retention_ferrihydrite_Gao_13_pub_access.pdf

Wendell P. Ela

Papers

TCLP underestimates leaching of arsenic from solid residuals under landfill conditions.

A review of irregular time series data handling with gated recurrent neural networks

Effect of pH, competitive anions and NOM on the leaching of arsenic from solid residuals

Effect of silicic acid on arsenate and arsenite retention mechanisms on 6-L ferrihydrite: A spectroscopic and batch adsorption approach

Fenton-driven chemical regeneration of MTBE-spent GAC