Perfluoroalkyl chemical adsorption by granular activated carbon: Assessment of particle size impact on equilibrium parameters and associated rapid small-scale column test scaling assumptions.

Single-solute batch kinetic and isotherm experiments were conducted in Type 1 (18.2 MΩ·cm resistivity) water supplemented with 10 mM carbonate buffer (pH 7.75, 25 °C) for nine drinking water relevant perfluoroalkyl chemicals and three bituminous-coal based granular activated carbons (GACs).

Modeling Nicotine-Induced Chlorine Loss in Drinking Water Using Updated EPANET-MSX.

Multispecies water quality modeling is critical for simulating complex chemical reactions in drinking water distribution systems. An updated EPANET 2.2-compatible version of EPANET multi-species eXtension (EPANET-MSX) was used, which included dispersion and improved mass balance reporting, to simulate an experimental study.

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.

Random Walk Particle Tracking to Model Dispersion in Steady Laminar and Turbulent Pipe Flow.

To accurately model a two-dimensional solute transport in drinking water pipes and determine the effective dispersion coefficients for one-dimensional water quality models of water distribution systems, a random walk particle tracking approach was developed to analyze the advection and dispersion processes in circular pipes. The approach considers a solute particle's two-dimensional random movement caused by molecular or turbulent diffusion and associated velocity profile, and can simulate any mixing time and accurately model the longitudinal distribution of the solute concentration. For long mixing times, the simulation results agreed with a previous analytically derived solution.

Pressure dependent analysis in premise plumbing system modeling.

Modeling premise plumbing systems requires accurate treatment of fixture-specific pressure and flow rate relationships. Each fixture in a building may experience different flow rates based on variable service pressure, its unique pressure-flow behavior, and demands throughout the building. Unique experimentally derived pressure-flow parameters for four faucets, a shower/tub fixture, and toilet were developed.

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.

Relative Water Age in Premise Plumbing Systems Using an Agent-Based Modeling Framework.

Tools used to predict hydraulics and water quality within premise plumbing systems have gained recent interest. An open-source Python-based tool-PPMtools-for modeling and analyzing premise plumbing systems with WNTR or EPANET is presented. A relative water age-the time water has spent in a home-study using three real-world single-family homes was used to demonstrate PPMtools.

Near real-time event detection for watershed monitoring with CANARY.

Illicit discharges in surface waters are a major concern in urban environments and can impact ecosystem and human health by introducing pollutants (, petroleum-based chemicals, metals, nutrients) into natural water bodies. Early detection of pollutants, especially those with regulatory limits, could aid in timely management of sources or other responses. Various monitoring techniques (, sensor-based, automated sampling) could help alert decision makers about illicit discharges.

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.

Lagrangian Method to Model Advection-Dispersion-Reaction Transport in Drinking Water Pipe Networks.

A Lagrangian method to simulate the advection, dispersion, and reaction of a single chemical, biological, or physical constituent within drinking water pipe networks is presented. This Lagrangian approach removes the need for fixed computational grids typically required in Eulerian and Eulerian-Lagrangian methods and allows for nonuniform computational segments. This makes the method fully compatible with the advection-reaction water quality engine currently used in EPANET.

Evaluating Manual Sampling Locations for Regulatory and Emergency Response.

Drinking water systems commonly use manual or grab sampling to monitor water quality, identify or confirm issues, and verify that corrective or emergency response actions have been effective. In this paper, the effectiveness of regulatory sampling locations for emergency response is explored. An optimization formulation based on the literature was used to identify manual sampling locations to maximize overall nodal coverage of the system.

Framework for Modeling Lead in Premise Plumbing Systems Using EPANET.

The lead contamination of drinking water in homes and buildings remains an important public health concern. In order to assess strategies to measure and reduce exposure to lead from drinking water, models are needed that incorporate the multiple factors affecting lead concentrations in premise plumbing systems (PPS). In this study, the use of EPANET, a commonly used hydraulic and water quality model for water distribution systems, was assessed for its ability to predict lead concentrations in PPS.

Variability and sampling of lead (Pb) in drinking water: Assessing potential human exposure depends on the sampling protocol.

Lead (Pb) in drinking water has re-emerged as a modern public health threat which can vary widely in space and in time (i.e., between homes, within homes and even at the same tap over time).

Quantifying hydraulic and water quality uncertainty to inform sampling of drinking water distribution systems.

Sampling of drinking water distribution systems is performed to ensure good water quality and protect public health. Sampling also satisfies regulatory requirements and is done to respond to customer complaints or emergency situations. Water distribution system modeling techniques can be used to plan and inform sampling strategies.

Effectiveness of point-of-use/point-of-entry systems to remove per- and polyfluoroalkyl substances from drinking water.

The contamination of groundwater sources with per- and polyfluoroalkyl substances (PFAS) in the United States is a widespread problem for the drinking water industry. Well water supplies in the municipalities of Fountain, Security, and Widefield, Colorado, contain perfluorooctanoic acid and perfluorooctane sulfonate levels greater than the U.S.

Understanding the Impact of Mesh on Tank Overflow System Capacity.

A 2016 incident that resulted in damage to a water storage tank's roof motivated pilot-scale experiments to be conducted to determine the impact of mesh on tank overflow capacity. A clean mesh installed near the outlet of an overflow system did not reduce the capacity during the weir dominated flow regime. The impact of a mesh was found to be a reduction in the area available to flow, which was found to lower the achievable capacity through the system.

Modeling Fate and Transport of Arsenic in a Chlorinated Distribution System.

Experimental and modeling studies were conducted to understand the fate and transport properties of arsenic in drinking water distribution systems. Pilot scale experiments were performed in a distribution system simulator by injecting arsenic and measuring both adsorption onto iron pipe material and the oxidation of arsenite by hypochlorite in tap water to form arsenate. A mathematical model describing these processes was developed and simulated using EPANET-MSX, a hydraulic and multi-species water quality software for pipe networks.

CANARY Eases Water Quality Event Detection.

A free software tool from the US Environmental Protection Agency was put through its paces at a midsize water utility and bolstered the utility's water quality event-detection capabilities.

Application of the CANARY event detection software for real-time performance monitoring of decentralized water reuse systems.

Real-time monitoring of water reuse systems ensures the production of high quality water to protect human health at the point-of-use. In this study, several online real-time sensors were utilized to monitor effluent from a wastewater fed laboratory-scale membrane bioreactor (MBR) under natural and simulated failure conditions. These simulated failures included adding reactor mixed liquor to emulate a membrane breach, and spiking MS2 bacteriophage into the reactor to create a high viral load, which might be observed during an outbreak.