Impact of phosphate addition on PFAS treatment performance for drinking water.

Adding new unit operations to drinking water treatment systems requires consideration of not only efficacy for its design purpose but also costs, water quality characteristics, impact on overall regulatory compliance, and impact of other treatment unit operations. Here, pilot study results for ion exchange (IX) and granular activated carbon (GAC) are presented for a utility with both per- and polyfluoroalkyl substances (PFAS) and volatile organic contaminant removal needs. Specifically, the impact of upstream air stripping and phosphate addition on PFAS treatment performance was evaluated.

A critical review of perfluoroalkyl and polyfluoroalkyl substances (PFAS) landfill disposal in the United States.

Landfills manage materials containing per- and polyfluoroalkyl substances (PFAS) from municipal solid waste (MSW) and other waste streams. This manuscript summarizes state and federal initiatives and critically reviews peer-reviewed literature to define best practices for managing these wastes and identify data gaps to guide future research. The objective is to inform stakeholders about waste-derived PFAS disposed of in landfills, PFAS emissions, and the potential for related environmental impacts.

Impact of water quality and operational factors on microcystin removal by powdered activated carbon.

The feasibility of using a 2 fractional factorial design to screen the relative importance of six water quality and operational factors in the removal of microcystin-LR (MC-LR) by powdered activated carbon (PAC) was evaluated through jar testing. The factors were: PAC type, PAC dose, total organic carbon (TOC) concentration, turbidity, alum dose, and timing of PAC versus coagulant application. Follow-up tests were performed to examine the interaction of PAC dose and TOC concentrations.

Sleep Architecture and EEG Power Spectrum Following Cumulative Sleep Restriction: A Comparison between Typically Developing Children and Children with ADHD.

No studies have looked at the effects of cumulative sleep restriction (CSR) on sleep architecture or the power spectrum of sleep EEG (electroencephalogram) in school-age children, as recorded by PSG (polysomnography). This is true for both typically developing (TD) children and children with ADHD (attention deficit/hyperactivity disorder), who are known to have more sleep difficulties. Participants were children (ages 6-12 years), including 18 TD and 18 ADHD, who were age- and sex-matched.

Polanyi adsorption potential theory for estimating PFAS treatment with granular activated carbon.

Per- and polyfluoroalkyl substances (PFAS) are a group of chemicals that have gained interest because some PFAS have been shown to have negative health effects and prolonged environmental and biological persistence. Chemicals classified as PFAS have a wide range of chemical moieties that impart widely variable properties, leading to a range of water treatment process efficacies. The Polanyi Potential Adsorption Theory was used to estimate Freundlich isotherm parameters to predict the efficacy of granular activated carbon (GAC) treatment for 428 PFAS chemicals for which the vast majority had no previously published treatment data.

Validating the use of lyophilized natural organic matter as background material in GAC rapid small-scale column tests.

Utilities often test the effectiveness of different granular activated carbons (GACs) to determine which is most advantageous for their system. For surface water systems, in particular, the seasonal and annual variability of natural organic matter (NOM) in the source water makes it difficult to benchmark the effectiveness of GACs over multiple contract periods. This study produced stable, lyophilized NOM from the filtered water (FW), i.

High-pressure membrane filtration processes for separation of Per- and polyfluoroalkyl substances (PFAS).

The development of remediation technology for Per- and poly-fluoroalkyl substances (PFAS) has become one of the nation's top research priorities as adverse impacts to environmental and human health have been increasingly identified. Of various water treatment routes, high-pressure membrane processes such as nanofiltration (NF) and reverse osmosis (RO) are considered most promising by virtue of the excellent rejection of both short- and long-chain PFAS and the proven technological maturity demonstrated with various water sources. Consequently, research activities have rapidly increased to accommodate research needs to advance NF and RO processes targeting PFAS removal from the aquatic environment.

Modeling PFAS Removal Using Granular Activated Carbon for Full-Scale System Design.

Per- and polyfluoroalkyl substances (PFAS) are increasingly of interest to drinking water utilities due to state regulations, the release of federal and state health advisories, and public concern. Pilot-scale data were fitted for 16 PFAS species and five commercial-activated carbons using an open-source pore and surface diffusion model that includes an automated parameter-fitting tool. The estimated model parameters are presented, and an uncertainty analysis was evaluated considering the expected temporal variability of influent concentrations.

Per- and polyfluoroalkyl substances in the environment.

Over the past several years, the term PFAS (per- and polyfluoroalkyl substances) has grown to be emblematic of environmental contamination, garnering public, scientific, and regulatory concern. PFAS are synthesized by two processes, direct fluorination (e.g.

Managing and treating per- and polyfluoroalkyl substances (PFAS) in membrane concentrates.

Per- and polyfluoroalkyl substances (PFAS), which are present in many waters, have detrimental impacts on human health and the environment. Reverse osmosis (RO) and nanofiltration (NF) have shown excellent PFAS separation performance in water treatment; however, these membrane systems do not destroy PFAS but produce concentrated residual streams that need to be managed. Complete destruction of PFAS in RO and NF concentrate streams is ideal, but long-term sequestration strategies are also employed.

Avoiding pitfalls when modeling removal of per- and polyfluoroalkyl substances by anion exchange.

Per- and polyfluoroalkyl substances (PFAS) are receiving a great deal of attention from regulators, water utilities, and the general public. Anion-exchange resins have shown high capacities for removal of these substances from water, but there is currently a paucity of ion-exchange treatment models available to evaluate performance. In this work, important theoretical and practical considerations are discussed for modeling PFAS removal from drinking water using gel-type, strong-base anion-exchange resin in batch and column processes.

Estimating costs for nitrate and perchlorate treatment for small drinking water systems.

When choosing a treatment technology for nitrate or perchlorate removal, drinking water utilities overwhelmingly choose ion exchange. However, of late, biological treatment and point-of-use systems have received a great deal of attention. This article utilizes several new U.

Even a Mild Sleep Restriction Can Impact Daytime Functioning in Children with ADHD and Their Typically Developing Peers.

Objectives/background: Correlational studies show that short sleep is associated with negative daytime outcomes in school-aged children, but there are few experimental sleep manipulation studies to assess whether this is a causal relation. The aim of this study was to determine the impact of mild, cumulative sleep restriction on daytime functioning of typically developing (TD) children and children with attention-deficit/hyperactivity disorder (ADHD).

Participants: A total of 36 school-aged children (n = 18 TD; n = 18 ADHD), aged 6-11 years participated.

Modeled Impacts of Drinking Water Pb Reduction Scenarios on Children's Exposures and Blood Lead Levels.

In recent years, environmental lead (Pb) exposure through drinking water has resulted in community public health concerns. To understand potential impacts on blood Pb levels (BLLs) from drinking water Pb reduction actions (i.e.

Social influences on binge drinking in emerging adults: Which social network members matter most?

Binge drinking peaks in emerging adulthood and is associated with a myriad of negative consequences. Research indicates that social network members have a significant influence on binge drinking. In particular, theory suggests that drinking habits of romantic partners and peers have a stronger influence on emerging-adult binge drinking than do drinking habits of siblings and parents.

Occurrence of Per- and Polyfluoroalkyl Substances (PFAS) in Source Water and Their Treatment in Drinking Water.

Per-and polyfluoroalkyl substances (PFAS) occurrence in drinking water and treatment methods for their removal are reviewed. PFAS are fluorinated substances whose unique properties make them effective surface-active agents with uses ranging from stain repellants to fire-fighting foams. In response to concerns about drinking water contamination and health risks from PFAS exposure, the United States Environmental Protection Agency published Health Advisories (HAs) for perfluorooctanoic acid and perfluorooctane sulfonic acid.

Comprehensive assessment of a chlorinated drinking water concentrate in a rat multigenerational reproductive toxicity study.

Some epidemiological studies report associations between drinking water disinfection byproducts (DBPs) and adverse reproductive/developmental effects, e.g., low birth weight, spontaneous abortion, stillbirth, and birth defects.

Disinfection byproduct formation in reverse-osmosis concentrated and lyophilized natural organic matter from a drinking water source.

Drinking water treatment and disinfection byproduct (DBP) research can be complicated by natural organic matter (NOM) temporal variability. NOM preservation by lyophilization (freeze-drying) has been long practiced to address this issue; however, its applicability for drinking water research has been limited because the selected NOM sources are atypical of most drinking water sources. The purpose of this research was to demonstrate that reconstituted NOM from a lyophilized reverse-osmosis (RO) concentrate of a typical drinking water source closely represents DBP formation in the original NOM.

Developmental toxicity evaluations of whole mixtures of disinfection by-products using concentrated drinking water in rats: gestational and lactational effects of sulfate and sodium.

A developmental toxicity bioassay was used in three experiments to evaluate water concentrates for suitability in multigenerational studies. First, chlorinated water was concentrated 135-fold by reverse osmosis; select lost disinfection by-products were spiked back. Concentrate was provided as drinking water to Sprague-Dawley and F344 rats from gestation day 6 to postnatal day 6.

Removal of estrogens and estrogenicity through drinking water treatment.

Estrogenic compounds have been shown to be present in surface waters, leading to concerns over their possible presence in finished drinking waters. In this work, two in vitro human cell line bioassays for estrogenicity were used to evaluate the removal of estrogens through conventional drinking water treatment using a natural water. Bench-scale studies utilizing chlorine, alum coagulation, ferric chloride coagulation, and powdered activated carbon (PAC) were conducted using Ohio River water spiked with three estrogens, 17β-estradiol, 17α-ethynylestradiol, and estriol.

Microwave-assisted green synthesis of silver nanostructures.

Over the past 25 years, microwave (MW) chemistry has moved from a laboratory curiosity to a well-established synthetic technique used in many academic and industrial laboratories around the world. Although the overwhelming number of MW-assisted applications today are still performed on a laboratory (mL) scale, we expect that this enabling technology may be used on a larger, perhaps even production, scale in conjunction with radio frequency or conventional heating. Microwave chemistry is based on two main principles, the dipolar mechanism and the electrical conductor mechanism.

Novel thermally stable poly(vinyl chloride) composites for sulfate removal.

BaCO(3) dispersed PVC composites were prepared through a polymer re-precipitation method. The composites were tested for sulfate removal using rapid small scale column test (RSSCT) and found to significantly reduce sulfate concentration. The method was extended to synthesize barium carbonate-loaded silica aero-gels-polyvinyl chloride (PVC) polymer composites.

Concentration, chlorination, and chemical analysis of drinking water for disinfection byproduct mixtures health effects research: U.S. EPA's Four Lab Study.

The U.S. Environmental Protection Agency's "Four Lab Study" involved participation of researchers from four national Laboratories and Centers of the Office of Research and Development along with collaborators from the water industry and academia.

Factors affecting atrazine concentration and quantitative determination in chlorinated water.

Although the herbicide atrazine has been reported to not react measurably with free chlorine during drinking water treatment, this work demonstrates that at contact times consistent with drinking water distribution system residence times, a transformation of atrazine can be observed. Some transformation products detected through the use of high performance liquid chromatography-electrospray mass spectrometry are consistent with the formation of N-chloro atrazine. The effects of applied chlorine, pH, and reaction time on the transformation reaction were studied to help understand the practical implications of the transformation on the accurate determination of atrazine in drinking waters.