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  • Keyword = ’homeland security’ AND ‘water treatment’ AND chlorination OR (chloramine OR biofilm OR monochloramine OR ‘chlorine inactivation’) NOT (presentation OR poster).
Records 1 to 25 of 344

2024
Closing Dichloramine Decomposition Nitrogen and Oxygen Mass Balances: Relative Importance of End-Products from the Reactive Nitrogen Species Pathway
(JOURNAL) [Published : Jan 30, 2024]
During dichloramine decomposition, the relative importance of nitrogen and oxygen containing end-products from the reactive nitrogen species pathway is unknown.  At pH 9 with and without 10 μM total dimethylamine (TOTDMA) and 200, 400, or 800 μeq Cl2•L−1 initial dichloramine, nit...
Composition of active bacterial communities and presence of opportunistic pathogens in disinfected and non-disinfected drinking water distribution systems in Finland
(JOURNAL) [Published : Jan 01, 2024]
Many factors, including microbiome structure and activity in the drinking water distribution system (DWDS), affect the colonization potential of opportunistic pathogens. The present study aims to describe the dynamics of active bacterial communities in DWDS and identify the facto...
2023
Decontamination of Malathion from Drinking Water Distribution System and Premise Plumbing Infrastructure
(PUBLISHED REPORT) [Published : May 31, 2023]
This report summarizes the results of infrastructure decontamination experiments performed at the WSTB.  These experiments focused on simulating contamination of drinking water distribution pipes with a commonly available insecticide formulation containing malathion.  M...
Field- and Pilot-Scale Approaches to Assess Finished Water Storage Tanks
(JOURNAL) [Published : Dec 06, 2023]
Finished water storage facilities are tanks or reservoirs used to store water that will undergo no further treatment to reduce microbial pathogens. Storage tanks are vulnerable to contamination and excess water retention time may cause depletion of disinfectant residual which cre...
Investigation of Chloramines, Disinfection Byproducts, and Nitrification in Chloraminated Drinking Water Distribution Systems
(JOURNAL) [Published : Jan 01, 2023]
The lack of widely available methods for distinguishing and quantifying organic chloramines has raised concerns for maintaining effective disinfectant residuals in chloraminated drinking water distribution systems (CDWDSs). This study provided quantitative estimation of dichloram...
Microelectrode evaluation of in situ oxidant reactivity and pH variability at new ductile iron and copper coupon surfaces
(JOURNAL) [Published : Sep 01, 2023]
This study represents an important first step towards using microelectrodes to (1) understand and provide direct measurement of oxidant microprofiles from the bulk water to the metal surface; (2) determine pipe wall reactivity using the directly measured concentrations profiles v...
Nitrite Quantification by Second Derivative Chemometric Models Mitigates Natural Organic Matter Interferences under Chloraminated Drinking Water Distribution System Conditions
(JOURNAL) [Published : Feb 01, 2023]
Nitrite (NO2−) produced during nitrification episodes in chloraminated drinking water distribution systems (CDWDSs) is typically quantified using ion chromatography (IC) or colorimetric techniques.  NO2− can also be quantified using chemometric models (CMs) formulated using molar...
2022
Apparent Reactivity of Bromine in Bromochloramine Depends on Synthesis Method: Implicating Bromine Chloride and Molecular Bromine as Important Bromine Species
(JOURNAL) [Published : Dec 01, 2022]
The chloramination of bromide containing waters results in the formation of the bromine containing haloamines: monobromamine, dibromamine, and bromochloramine (NHBrCl). Many studies have directly shown that bromamines are more reactive than chloramines in oxidation and substituti...
Evaluation of Preformed Monochloramine Reactivity with Processed Natural Organic Matter and Scaling Methodology Development for Concentrated Waters
(JOURNAL) [Published : Dec 09, 2022]
To evaluate natural organic matter (NOM) processing impacts on preformed monochloramine (PM) reactivity and as a first step in creating concentrated disinfection byproduct (DBP) mixtures from PM, a rational methodology was developed to proportionally scale PM NOM related demand i...
Occurrence Revisited: Mycobacterium avium and Mycobacterium intracellulare in potable water in the USA
(JOURNAL) [Published : Apr 01, 2022]
Mycobacterium avium and Mycobacterium intracellulare belong to the Mycobacterium avium complex (MAC) and are two clinically significant bacteria that can cause infections and diseases in humans. These bacteria are opportunistic water-borne pathogens that are highly resistant to w...
The Water On Wheels Mobile Emergency Water Treatment System
(NEWSLETTER ARTICLE) [Published : Dec 01, 2022]
Following a natural or manmade disaster, a community’s water treatment plant or distribution system may be rendered incapable of providing safe water to all or portions of their drinking water distribution system. The lack of safe drinking water can have serious effects on ...
2021
A Comprehensive Evaluation of Monochloramine Disinfection on Water Quality, Legionella and Other Important Microorganisms in a Hospital
(JOURNAL) [Published : Feb 01, 2021]
Opportunistic pathogens such as Legionella are of significant public health concern in hospitals. Microbiological and water chemistry parameters in hot water throughout an Ohio hospital were monitored monthly before and after the installation of a monochloramine disinfection syst...
A Novel Thin-Film Technique to Improve Accuracy of Fluorescence-Based Estimates for Periphytic Biofilms
(JOURNAL) [Published : May 23, 2021]
Recent studies suggest that photophysiological parameters for intact substrates with depth (e.g., periphytic biofilms, microphytobenthos) are overestimated by pulse-amplitude modulated (PAM) fluorometry. This overestimation results from depth-integration effects, following the ac...
Chloramine Concentrations within Distribution Systems and Their Effect on Heterotrophic Bacteria, Mycobacterial Species, and Disinfection Byproducts
(JOURNAL) [Published : Oct 15, 2021]
Background: Chloramine is a disinfectant used to maintain microbial control throughout a public water suppliers’ distribution system. This current study investigated the relationship between chloramine concentration and heterotrophic plate counts (HPC) and nontuberculous mycobact...
Ecological Insights into Assembly Processes and Network Structures of Bacterial Biofilms in Full-scale Biologically Active Carbon Filters under Ozone Implementation
(JOURNAL) [Published : Jan 10, 2021]
To address the adverse effects of harmful algal blooms, there are increased demands over the implementation of ozone-biologically active carbon (BAC) filters in the drinking water treatment plants. Although the microbial biofilms are vital elements to support the proper performan...
Legionella and other opportunistic pathogens in full-scale chloraminated municipal drinking water distribution systems
(JOURNAL) [Published : Oct 15, 2021]
Water-based opportunistic pathogens (OPs) are a leading cause of drinking-water-related disease outbreaks, especially in developed countries such as the United States (US). Physicochemical water quality parameters, especially disinfectant residuals, control the (re)growth, presen...
Legionella: A Promising Supplementary Indicator of Microbial Drinking Water Quality in Municipal Engineered Water Systems
(JOURNAL) [Published : Nov 10, 2021]
Opportunistic pathogens (OPs) are natural inhabitants and the predominant disease causative biotic agents in municipal engineered water systems (EWSs). In EWSs, OPs occur at high frequencies and concentrations, cause drinking-water-related disease outbreaks, and are a major facto...
Metagenomic Profile of Microbial Communities in a Drinking Water Storage Tank Sediment after Sequential Exposure to Monochloramine, Free Chlorine, and Monochloramine
(JOURNAL) [Published : May 14, 2021]
Sediment accumulation in drinking water storage facilities may lead to water quality degradation, including biological growth and disinfectant decay. The current research evaluated the microbial community present in a sediment after sequential exposure to monochloramine, free chl...
Method 127: Determination of Monochloramine Concentration in Drinking Water
(PUBLISHED REPORT) [Published : Mar 18, 2021]
A method for the determination of monochloramine concentration in drinking water has been developed. It requires the use of a bench-top or portable colorimeter, spectrophotometer, or a mesofluidic channel pump colorimeter (also known as a portable parallel analyzer (PPA)). This m...
Monochloramine Measurement
(JOURNAL) [Published : Oct 04, 2021]
The publication highlights a new EPA method to measure monochloramine in drinking water (EPA Method 127) along with a related peer reviewed journal article that was recently published.
Optimizing disinfectant residual dosage in engineered water systems to minimize the overall health risks of opportunistic pathogens and disinfection by-products
(JOURNAL) [Published : May 20, 2021]
This Discussion argues that municipal water utilities may need to consider the health risks of both opportunistic pathogens (OPs) and disinfection by-products (DBPs) while selecting disinfectant residual dosages or levels in engineered water systems. OPs are natural inhabitants i...
Quantification of Legionella pneumophila by qPCR and Culture in Tap Water with Different Concentrations of Residual Disinfectants and Heterotrophic Bacteria
(JOURNAL) [Published : Jun 20, 2021]
Legionellosis prevalence is increasing in the United States. This disease is caused primarily by the bacterium Legionella pneumophila that is found in water and transmitted by the inhalation of aerosols. This pathogen has a slow growth rate and can “hide” in amoeba making it diff...
Temperature impact on monochloramine, free ammonia, and free chlorine indophenol methods
(JOURNAL) [Published : Jan 01, 2021]
The colorimetric monochloramine indophenol (NH2Cl-IP) method is typically used for determining monochloramine (NH2Cl) concentrations in chloraminated drinking water systems (DWSs) and chloramine-related research. The NH2Cl-IP method is not approved for US DWS compliance sampling...
Updated Reaction Pathway for Dichloramine Decomposition: Formation of Reactive Nitrogen Species and N-Nitrosodimethylamine
(JOURNAL) [Published : Feb 02, 2021]
Nitrous oxide (N2O) and dissolved oxygen (DO) were quantified during 800 μeq Cl2 L–1 dichloramine (NHCl2) decomposition (pH 7–10) with or without 10 μM total dimethylamine (TOTDMA) addition. Chemical kinetics and yields supported nitroxyl (HNO) formed from NHCl2 hydrolysis and di...
2020
Assessing Fluorescence as an Early-Warning Indicator of Biological Ammonia Oxidation in Chloraminated Water: Laboratory-Scale Annular Reactor Studies with a Benchtop Fluorometer
(BOOK) [Published : Nov 10, 2020]
This project identified and validated fluorescence intensity at specific wavelength pairs (IEX/EM) for early detection of nitrification in chloraminated distribution systems. Thirteen biofilm annular reactor (AnR) tests were completed using feedwaters from Fayetteville (FW-F), Da...