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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 326

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...
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...
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...
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 ma...
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...
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...
Assessing the chemical compositions and disinfection byproduct formation of biofilms: Application of fluorescence excitation-emission spectroscopy coupled with parallel factor analysis
(JOURNAL) [Published : May 01, 2020]
There are increased concerns over biofilms’ contribution to disinfection by-product (DBP) formation in engineered water systems (EWS). However, monitoring the biomolecular characteristics of biofilms to understand their impacts on DBP formation has been a great challenge as it re...
Design and Evaluation of Degassed Anaerobic Membrane Biofilm Reactors for Improved Methane Recovery
(JOURNAL) [Published : Jun 10, 2020]
Anaerobic treatment of domestic wastewater (DWW) produces methane, which can remain dissolved in solution. Dissolved methane needs to be recovered efficiently to prevent subsequent release into the environment and allow for beneficial use as an energy product. While several membr...
Fire Hydrant Flushing Treatment Diffusser and Effectiveness of Flushing Hydrants for Contamination Removal
(SUMMARY) [Published : Jul 31, 2020]
Flushing contaminated water out of the distribution system using the existing network of fire hydrants is considered the most probable first action in response to a drinking water system contamination incident. Hydrant Flushing and Chlorination experiments were conducted at the W...
Impact of algal organic matter on the performance, cyanotoxin removal, and biofilms of biologically-active filtration systems
(JOURNAL) [Published : Oct 01, 2020]
In this study, five parallel laboratory-scale columns were used to investigate the impacts of AOM on the performance and bacterial community structure of GAC filters at different empty bed contact times (EBCTs). The results of excitation and emission matrix analysis indicated tha...
Legionella Diversity and Spatiotemporal Variation in the Occurrence of Opportunistic Pathogens within a Large Building Water System
(JOURNAL) [Published : Jul 13, 2020]
Understanding Legionella survival mechanisms within building water systems (BWSs) is challenging due to varying engineering, operational, and water quality characteristics unique to each system. This study aimed to evaluate Legionella, mycobacteria, and free-living amoebae occur...
Legionellosis and recent advances in technologies for Legionella control in premise plumbing systems: A review
(JOURNAL) [Published : Mar 02, 2020]
This review discusses Legionella, among the most prolific and publicly well-known waterborne pathogens. The number of cases associated with Legionella continue to rise, as does its public awareness. Currently, cases associated with premise plumbing account for the largest numbe...
Monitoring of Nitrification in Chloraminated Drinking Water Distribution Systems With Microbiome Bioindicators Using Supervised Machine Learning
(JOURNAL) [Published : Sep 16, 2020]
Many water utilities in the US using chloramine as disinfectant treatment in their distribution systems have experienced nitrification episodes, which detrimentally impact the water quality. A chloraminated drinking water distribution system (DWDS) simulator was operated through...
Orthophosphate Interactions with Destabilized PbO2 Scales
(JOURNAL) [Published : Nov 17, 2020]
This research presents two case studies in which a change in disinfection from free chlorine to chloramine caused an issue with lead corrosion. In both systems the predominant Pb(IV) scale destabilized as a result of the disinfection change. Orthophosphate was used in both system...
Role of Carbonate Species on General Acid Catalysis of Bromide Oxidation by Hypochlorous Acid (HOCl) and Oxidation by Molecular Chlorine (Cl2)
(JOURNAL) [Published : Dec 15, 2020]
Bromide ion (Br–) oxidation kinetics have taken on renewed importance in chloramine disinfection as several seconds to several minutes of free chlorination often precedes free ammonia addition. In such systems, the potential for bromine–substituted disinfection by–products must b...
Trophodynamics of Per- and Polyfluoroalkyl Substances in the Food Web of a Large Atlantic Slope River
(JOURNAL) [Published : Jun 02, 2020]
Per- and polyfluoroalkyl substances (PFASs) have attracted scientific and regulatory attention due to their persistence, bioaccumulative potential, toxicity, and global distribution. We determined the accumulation and trophic transfer of 14 PFASs (5 short-chain and 9 long-chain) ...
Use a Hold Study and Web-Based App to Assess Chloramine Demand
(JOURNAL) [Published : Jun 02, 2020]
The chloramine hold study is an effective tool to assess chloramine residual stability. Chloramine demand may be assessed relatively easily by conducting a hold study and comparing the results to simulated chloramine concentrations using a free web-based application (WBA). A ch...
Bringing Community Ecology to Bear on the Issue of Antimicrobial Resistance
(JOURNAL) [Published : Nov 15, 2019]
Antimicrobial resistance (AMR) is a global concern, pertaining not only to human health but also to the health of industry and the environment. AMR research has traditionally focused on genetic exchange mechanisms and abiotic environmental constraints, leaving important aspects o...
Chlorine and monochloramine disinfection of Legionella pneumophila colonizing copper and PVC drinking water biofilms
(JOURNAL) [Published : Jan 25, 2019]
Building water systems (BWSs) promote the regrowth and survival of opportunistic pathogens, such as Legionella pneumophila, especially within biofilms (BFs), where most drinking water (DW) microbes reside. However, compared to their planktonic (PL) form, disinfection efficacy fo...
Dynamics of the Physiochemical and Community Structures of Biofilms under the Influence of Algal Organic Matter and Humic Substances
(JOURNAL) [Published : Jul 01, 2019]
This study aims to investigate the effects of AOM and HS-impacted water in biofilm development under unchlorinated drinking water distribution system (DWDS) conditions. Simulated DWDSs were constructed and operated for 168 days. The formation, development, physiochemical characte...
Evaluation of Monochloramine and Free Chlorine Penetration in a Drinking Water Storage Tank Sediment Using Microelectrodes
(JOURNAL) [Published : Jul 09, 2019]
Sediment accumulation in water storage tanks may protect microorganisms from disinfectant exposure, causing water quality degradation. However, microbial activity and disinfectant penetration within water storage sediment remains largely uncharacterized. This study evaluated mono...