Publications by authors named "Westerhoff P"

Wastewater receives per- and polyfluoroalkyl substances (PFAS) from diverse consumer and industrial sources, and discharges are known to be a concern for drinking water quality. The PFAS family includes thousands of potential chemical structures containing organofluorine moieties. Exposures to a few well-studied PFAS, mainly perfluoroalkyl acids (PFAA), have been associated with increased risk of many adverse health outcomes, prompting federal drinking water regulations for six compounds in 2024.

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  • Co-occurrence of metal oxo-anions like arsenate in drinking water can be harmful to human health, motivating the study of how to better predict their behavior in adsorption systems.
  • By integrating surface complexation models with pore surface diffusion models, researchers accurately predicted the adsorption behaviors of single and mixed solutes, helping to understand how different adsorbents interact with these contaminants.
  • The findings emphasized that enhancing the capacity and reactivity of adsorbents is more effective for improving water purification systems than merely focusing on pore design to minimize transport limitations.
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  • Accurately assessing risks from inorganic pollutants in groundwater is crucial, but existing water quality databases often lack sufficient data due to budget constraints and sample collection challenges.
  • Two advanced data imputation techniques, AMELIA and MICE, were compared, with AMELIA proving more effective in managing missing values without creating excessive outliers.
  • The use of imputed data revealed significantly more potential health risks in groundwater samples, helping state agencies better allocate resources for monitoring and analysis, thus enhancing decision-making and prioritization for future sampling efforts.
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Phosphorus (P) removal from water and recovery into useable forms is a critical component of creating a sustainable P cycle, although mature technologies for P removal and recovery are still lacking. The goal of this paper was to advance the testing of novel materials for P removal and recovery from water by providing guidance on the development of more realistic aqueous matrices used during materials development. Literature reports of "new" materials to remove P from water are often difficult to compare in terms of performance because authors use a myriad of water chemistries containing P concentrations, pH, and competing ions.

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Activated carbon block (ACB) filters are widely used in point-of-use (POU) drinking technology to remove tastes, odors, and organic compounds from drinking water, and when modified can even remove inorganic pollutants (e.g., arsenate, lead, copper).

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Phosphorus (P) is essential for growing crops, but the supply of high-quality phosphate rock reserves used for fertilizer production is finite while losses of P from the food/waste system cause considerable environmental damage. A variety of emerging approaches in biotechnology are reviewed that hold promise for improving the sustainability of P use in the food/water systems. These include improved sensors, cell culture approaches to meat production, bio-based P adsorption and transformation strategies, advancements in understanding of polyphosphate-accumulating organisms, and new approaches involving biomineralization and anaerobic treatment.

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Sorption-based atmospheric water harvesting (SAWH) is a promising solution for localized high-quality water production. Application of SAWH indoors offers dual benefits of on-site water generation and humidity control. This study evaluated the use of SAWH for water production in residential or office buildings, employing a portable zeolite-based SAWH device.

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  • Researchers have developed a new photocatalytic reactor that converts carbon dioxide (CO) to formic acid (HCOOH) using an iron-based material on optical fibers, improving efficiency.
  • This dual-fiber system drastically increases the CO-to-HCOOH conversion rate and quantum efficiency (QE), achieving rates that are over 18 times better than traditional slurry methods.
  • The innovative design allows for efficient CO use with reduced energy consumption, eliminating the need for expensive metals typically found in other photocatalytic processes.*
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Recent regulatory actions aim to limit per- and polyfluoroalkyl substances (PFAS) concentrations in drinking water and wastewaters. Regenerable anion exchange resin (AER) is an effective separation process to remove PFAS from water but will require PFAS post-treatment of the regeneration wastestream. Electrocatalytic (EC) processes using chemically boron-doped diamond electrodes, stable in a wide range of chemical compositions show potential to defluorinate PFOA in drinking water and wastewater treatments.

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Membrane bioreactors (MBRs) are well-established and widely utilized technologies with substantial large-scale plants around the world for municipal and industrial wastewater treatment. Despite their widespread adoption, membrane fouling presents a significant impediment to the broader application of MBRs, necessitating ongoing research and development of effective antifouling strategies. As highly promising, efficient, and environmentally friendly chemical methods for water and wastewater treatment, advanced oxidation processes (AOPs) have demonstrated exceptional competence in the degradation of pollutants and inactivation of bacteria in aqueous environments, exhibiting considerable potential in controlling membrane fouling in MBRs through direct membrane foulant removal (MFR) and indirect mixed-liquor improvement (MLI).

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Uneven global distribution of phosphate rock deposits and the supply chains to transport phosphorus (P) make P fertilizers vulnerable to exogenous shocks, including commodity market shocks; extreme weather events or natural disasters; and geopolitical instability, such as trade disputes, disruption of shipping routes, and war. Understanding bidirectional risk transmission (global-to-local and local-to-global) in P supply and consumption chains is thus essential. Ignoring P system interdependencies and associated risks could have major impacts on critical infrastructure operations and increase the vulnerability of global food systems.

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In-situ hydrogen peroxide (HO) finds applications in disinfection and oxidation processes. Photoproduction of HO from water and oxygen, avoids reliance upon organic chemicals, and potentially enables smaller-sized or lower-cost reactors than electrochemical methods. In ultrapure water, we previously demonstrated a novel dual-fiber system coupling a light emitting diode (LED) with a metal-organic framework (MOF) catalyst-coated optical fiber (POF-MIL-101(Fe)) and O-based hollow-membrane fibers and achieved a remarkable HO yield, 308 ± 1.

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Nitrate contamination of surface and ground water is a significant global challenge. Most current treatment technologies separate nitrate from water, resulting in concentrated wastestreams that need to be managed. Membrane Catalyst-film Reactors (MCfR), which utilize in-situ produced nanocatalysts attached to hydrogen-gas-permeable hollow-fiber membranes, offer a promising alternative for denitrification without generating a concentrated wastestream.

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Thermal treatment has emerged as a promising approach for either the end-of-life treatment or regeneration of granular activated carbon (GAC) contaminated with per- and polyfluoroalkyl substances (PFAS). However, its effectiveness has been limited by the requirement for high temperatures, the generation of products of incomplete destruction, and the necessity to scrub HF in the flue gas. This study investigates the use of common alkali and alkaline-earth metal additives to enhance the mineralization of perfluorooctanesulfonate (PFOS) adsorbed onto GAC.

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Per- and polyfluoroalkyl substances (PFAS) are pervasive in industrial processes, eliciting public concern upon their release into municipal sewers or the environment. Removing PFAS from the environment has become an urgent need. However, because potential endpoints span from energy-intensive complete mineralization to partial PFAS transformation, understanding and developing metrics for evaluating PFAS treatment can be a challenge.

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  • Photocatalyst-coated optical fibers (P-OFs) can effectively degrade micropollutants like carbamazepine in various water systems by utilizing UV-A LEDs directly in water tanks, avoiding the need for additional separation systems.
  • Current challenges with P-OFs include light management issues, such as oversaturation of photocatalysts and short light transmission distances; however, strategies to improve light uniformity have been developed.
  • Adjustments in optical fiber parameters, such as patchiness and incident angles, led to significant enhancements in photocatalyst activation, achieving a three-fold increase in degradation rates and a 65% reduction in energy consumption.
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Recent advancements in membrane-assisted seawater electrolysis powered by renewable energy offer a sustainable path to green hydrogen production. However, its large-scale implementation faces challenges due to slow power-to-hydrogen (P2H) conversion rates. Here we report a modular forward osmosis-water splitting (FOWS) system that integrates a thin-film composite FO membrane for water extraction with alkaline water electrolysis (AWE), denoted as FOWS.

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The emergence of facial masks as a critical health intervention to prevent the spread of airborne disease and protect from occupational nanomaterial exposure highlights the need for fundamental insights into the interaction of nanoparticles (<200 nm) with modern polymeric mask filter materials. While most research focuses on the filtration efficiency of airborne particles by facial masks based on pore sizes, pressure drop, or humidity, only a few studies focus on the importance of aerosol surface charge versus filter surface charge and their role in the net particle filtration efficiency of mask filters. In this study, experiments were conducted to assess mask filter filtration efficiency using positively and negatively charged polystyrene particles (150 nm) as challenge aerosols at varying humidity levels.

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Water reuse is rapidly becoming an integral feature of resilient water systems, where municipal wastewater undergoes advanced treatment, typically involving a sequence of ultrafiltration (UF), reverse osmosis (RO), and an advanced oxidation process (AOP). When RO is used, a concentrated waste stream is produced that is elevated in not only total dissolved solids but also metals, nutrients, and micropollutants that have passed through conventional wastewater treatment. Management of this RO concentrate─dubbed municipal wastewater reuse concentrate (MWRC)─will be critical to address, especially as water reuse practices become more widespread.

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Centralized water infrastructure has, over the last century, brought safe and reliable drinking water to much of the world. But climate change, combined with aging and underfunding, is increasingly testing the limits of-and reversing gains made by-these large-scale water systems. To address these growing strains and gaps, we must assess and advance alternatives to centralized water provision and sanitation.

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While electrodialysis (ED) demonstrates lower energy consumption than reverse osmosis (RO) in the desalination of low salinity waters, RO continues to be the predominant technology for brackish water desalination. In this study, we probe this skewed market share and project the potential for future disruption by ED through systematic assessment of the levelized cost of water (LCOW). Using rigorous process- and economic-models, we minimize the LCOW of RO and ED systems, highlighting important tradeoffs between capital and operating expenditure for each technology.

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Per- and polyfluoroalkyl substances (PFAS) are a group of fluorinated organic contaminants classified as persistent in the aquatic environment. Early studies using targeted analysis approaches to evaluate the degradation of PFAS by advanced oxidation processes (AOP) in real water matrices may have been misinterpreted due to the presence of undetected or unknown PFAS in these matrices. The aims of the present study were to (1) screen selected commercially available AOPs (UV, UV + HO, O/HO) and UV photocatalysis in a pilot system using commercially used and novel photocatalysts (TiO, boron nitride [BN]) for removing PFAS contaminants and (2) evaluate their role on the conversion of non-detected/unknown to known PFAS compounds in real groundwater used as drinking water supplies.

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A key requirement for evaluating the safety of nano-enabled water treatment devices is measuring concentrations of insoluble nanomaterials released from devices into water that may be ingested by consumers. Therefore, there is a need for simple technique that uses commonly available commercial laboratory techniques to discriminate between nanoparticles and dissolved by-products of the nanomaterial (e.g.

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Carbon block filters, commonly employed as point-of-use (POU) water treatment components, effectively eliminate pathogens and adsorb undesirable tastes, odors, and organic contaminants, all while producing no water waste. However, they lack the capability to remove arsenic. Enabling the carbon block to remove arsenic could reduce its exposure risks in tap water.

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Biofilms give rise to a range of issues, spanning from harboring pathogens to accelerating microbial-induced corrosion in pressurized water systems. Introducing germicidal UV-C (200-280 nm) irradiation from light-emitting diodes (LEDs) into flexible side-emitting optical fibers (SEOFs) presents a novel light delivery method to inhibit the accumulation of biofilms on surfaces found in small-diameter tubing or other intricate geometries. This work used surfaces fully submerged in flowing water that contained , an opportunistic pathogen commonly found in water system biofilms.

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