scholarly journals Persistence of Nontuberculous Mycobacteria in a Drinking Water System after Addition of Filtration Treatment

2006 ◽  
Vol 72 (9) ◽  
pp. 5864-5869 ◽  
Author(s):  
Elizabeth D. Hilborn ◽  
Terry C. Covert ◽  
Mitchell A. Yakrus ◽  
Stephanie I. Harris ◽  
Sandra F. Donnelly ◽  
...  
Keyword(s):  
Drinking Water ◽  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Cold Water ◽  
Nontuberculous Mycobacteria ◽  
Treatment Plant ◽  
Water System ◽  
Drinking Water Treatment ◽  
Drinking Water System

ABSTRACT There is evidence that drinking water may be a source of infections with pathogenic nontuberculous mycobacteria (NTM) in humans. One method by which NTM are believed to enter drinking water distribution systems is by their intracellular colonization of protozoa. Our goal was to determine whether we could detect a reduction in the prevalence of NTM recovered from an unfiltered surface drinking water system after the addition of ozonation and filtration treatment and to characterize NTM isolates by using molecular methods. We sampled water from two initially unfiltered surface drinking water treatment plants over a 29-month period. One plant received the addition of filtration and ozonation after 6 months of sampling. Sample sites included those at treatment plant effluents, distributed water, and cold water taps (point-of-use [POU] sites) in public or commercial buildings located within each distribution system. NTM were recovered from 27% of the sites. POU sites yielded the majority of NTM, with >50% recovery despite the addition of ozonation and filtration. Closely related electrophoretic groups of Mycobacterium avium were found to persist at POU sites for up to 26 months. Water collected from POU cold water outlets was persistently colonized with NTM despite the addition of ozonation and filtration to a drinking water system. This suggests that cold water POU outlets need to be considered as a potential source of chronic human exposure to NTM.

The biological safety of distribution systems following UV disinfection in rural areas in Beijing, China

2013 ◽  
Vol 13 (3) ◽  
pp. 854-863 ◽  
Author(s):  
Wenjun Sun ◽  
Wenjun Liu ◽  
Lifeng Cui ◽  
Leibin Liu
Keyword(s):  
Drinking Water ◽  
Rural Areas ◽  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution System ◽  
Drinking Water Treatment ◽  
Uv Disinfection ◽  
Biological Safety ◽  
Drinking Water Standard

In rural areas, UV disinfection has a great potential for drinking water treatment because of the ability to achieve target disinfection levels and the ease of operation and maintenance; however, UV disinfection provides no disinfection residual to the water distribution system. This study examines the biological safety of rural water distribution systems following UV disinfection. The results showed that in all the tested villages, heterotrophic plate counts (HPC) were below 500 colony-forming units (CFU)/mL and total bacterial counts (TBC) were below 100 CFU/mL. Both meet the drinking water standard in China. The HPC concentration was related to the water temperature, the assimilable organic carbon (AOC) and water distribution system conditions. Total coliforms were detectable at some water distribution system sampling points in two out of eight villages.

scholarly journals Deficiencies in drinking water distribution systems in developing countries

2005 ◽  
Vol 3 (2) ◽  
pp. 109-127 ◽  
Author(s):  
Ellen J. Lee ◽  
Kellogg J. Schwab
Keyword(s):  
Developing Countries ◽  
Drinking Water ◽  
Distribution System ◽  
Urban Areas ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Pressure ◽  
Drinking Water Treatment ◽  
Human Consumption ◽  
Drinking Water Distribution Systems

Rapidly growing populations and migration to urban areas in developing countries has resulted in a vital need for the establishment of centralized water systems to disseminate potable water to residents. Protected source water and modern, well-maintained drinking water treatment plants can provide water adequate for human consumption. However, ageing, stressed or poorly maintained distribution systems can cause the quality of piped drinking water to deteriorate below acceptable levels and pose serious health risks. This review will outline distribution system deficiencies in developing countries caused by: the failure to disinfect water or maintain a proper disinfection residual; low pipeline water pressure; intermittent service; excessive network leakages; corrosion of parts; inadequate sewage disposal; and inequitable pricing and usage of water. Through improved research, monitoring and surveillance, increased understanding of distribution system deficiencies may focus limited resources on key areas in an effort to improve public health and decrease global disease burden.

scholarly journals Ammonia- and Nitrite-Oxidizing Bacterial Communities in a Pilot-Scale Chloraminated Drinking Water Distribution System

2002 ◽  
Vol 68 (1) ◽  
pp. 73-81 ◽  
Author(s):  
John M. Regan ◽  
Gregory W. Harrington ◽  
Daniel R. Noguera
Keyword(s):  
Drinking Water ◽  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Rflp Analysis ◽  
Drinking Water Treatment ◽  
Pilot Scale ◽  
Rrna Gene ◽  
Ammonia Oxidizing Bacteria ◽  
Drinking Water Distribution

ABSTRACT Nitrification in drinking water distribution systems is a common operational problem for many utilities that use chloramines for secondary disinfection. The diversity of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) in the distribution systems of a pilot-scale chloraminated drinking water treatment system was characterized using terminal restriction fragment length polymorphism (T-RFLP) analysis and 16S rRNA gene (ribosomal DNA [rDNA]) cloning and sequencing. For ammonia oxidizers, 16S rDNA-targeted T-RFLP indicated the presence of Nitrosomonas in each of the distribution systems, with a considerably smaller peak attributable to Nitrosospira-like AOB. Sequences of AOB amplification products aligned within the Nitrosomonas oligotropha cluster and were closely related to N. oligotropha and Nitrosomonas ureae. The nitrite-oxidizing communities were comprised primarily of Nitrospira, although Nitrobacter was detected in some samples. These results suggest a possible selection of AOB related to N. oligotropha and N. ureae in chloraminated systems and demonstrate the presence of NOB, indicating a biological mechanism for nitrite loss that contributes to a reduction in nitrite-associated chloramine decay.

Evaluation of a Taste and Odor Incident on the Ohio River

1999 ◽  
Vol 40 (6) ◽  
pp. 185-193 ◽  
Author(s):  
J. Noblet ◽  
L. Schweitzer ◽  
E. Ibrahim ◽  
K. D. Stolzenbach ◽  
L. Zhou ◽  
...  
Keyword(s):  
Drinking Water ◽  
Distribution System ◽  
Water Distribution ◽  
Treatment Plan ◽  
Sewage Treatment ◽  
Treatment Plant ◽  
Drinking Water Treatment ◽  
Ohio River ◽  
Isomer Ratio ◽  
Taste And Odor

This study describes a taste and odor event which occurred along the Ohio River during 1989 involving rinse water from a resin manufacturer that contained chemicals which reacted to form 2-ethyl-4-methyl-1,3-dioxolane (2EMD). The events under which the chemical was formed and transported from the resin manufacturing facility to the sewage treatment plan to the Ohio River are described. Taste and odors were detected in water supplies as far as 137 miles downstream from the point of discharge. Due to its hydrophilic nature, 2EMD was not sufficiently removed by the wastewater treatment plant using activated sludge treatment nor by drinking water treatment facilities downstream, even those which utilized granular activated carbon. 2EMD (consisting of cis:trans isomers, stable at a ratio of about 60:40) was the major component of the odor of the drinking water found in samples of the local water distribution system. An FPA panel described the synthesized cis/trans 60:40 isomer ratio of 2-ethyl-4-methyl-1,3-dioxolane as having a medicinal sweet or sickening sweet smell which matched the odor found in the samples from the impacted sites (resin manufacturer and drinking waters downstream).

scholarly journals Evaluation of Residual Disinfectant Levels in Public Drinking Water Distribution Systems in Relation to an Acanthamoeba Keratitis Outbreak - Illinois, 2002-2009

2021 ◽  
Author(s):  
Hannah Holsinger ◽  
Anna Blackstock ◽  
Sharon L. Roy ◽  
Susan Shaw
Keyword(s):  
Drinking Water ◽  
Environmental Protection Agency ◽  
Multiple Testing ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water System ◽  
Acanthamoeba Keratitis ◽  
Cook County ◽  
Entire Study ◽  
Corneal Injury

Acanthamoeba keratitis (AK) is a painful, potentially blinding eye disease associated with contact lens use and corneal injury. AK, caused by the free-living amoeba Acanthamoeba, is ubiquitous in the environment and has been isolated from municipal water supplies. It can be tolerant of normal chlorine levels in drinking water. An AK outbreak investigated in 2003-2005 in five Illinois counties showed a lower AK age-standardized rate ratio in Cook County than in surrounding counties and was hypothesized to be due in part to reductions in residual disinfectant levels (RDLs) in drinking water. We evaluated RDLs in public water systems in the same five Illinois counties over eight years (2002-2009) using a multivariable model of water system RDL measurements. Fitted RDLs for each county were in the acceptable range by United States Environmental Protection Agency standards for the entire study period. After correcting for multiple testing, two of the surrounding counties had fitted RDLs that differed from Cook County for one year. This pattern differed from the epidemiologic pattern of cases observed in the AK outbreak. Our findings do not support the hypothesis that the development of AK was associated with changes in RDLs in the five Illinois counties.

scholarly journals Application of model fitting technique to enhance bacterial regrowth potential (BRP) measurement for drinking water supply monitoring

2021 ◽  
Author(s):  
Wenjin Xue ◽  
Christopher W. K. Chow ◽  
John van Leeuwen
Keyword(s):  
Drinking Water ◽  
Water Supply ◽  
Water Samples ◽  
Distribution System ◽  
Distribution Systems ◽  
Tap Water ◽  
Treatment Plant ◽  
Drinking Water Supply ◽  
Water Supply Systems ◽  
Bacterial Regrowth

Abstract The bacterial regrowth potential (BRP) method was utilised to indirectly measure the assimilable organic carbon (AOC) as an indicator for the assessment of the microbial regrowth potential in drinking water distribution systems. A model using various microbial growth parameters was developed in order to standardise the experimental interpretation for BRP measurement. This study used 82 experimental BRP data sets of water samples collected from the water treatment plant to locations (customer taps) in the distribution system. The data were used to model the BRP process (growth curve) by a data fitting procedure and to obtain a best-fitted equation. Statistical assessments and model validation for evaluating the equation obtained by fitting these 82 sets of data were conducted, and the results show average R2 values were 0.987 for treated water samples (collected at the plant prior to chlorination) and 0.983 for tap water (collected at the customer taps). The F values obtained from the F-test are all exceeded their corresponding F critical values, and the results from the t-test also showed a good outcome. These results indicate this model would be successfully applied in modelling BRP in drinking water supply systems.

Control of biofilm growth in drinking water distribution system by biodegradable carbon and disinfectant residuals

2006 ◽  
Vol 6 (2) ◽  
pp. 147-151 ◽  
Author(s):  
X.-J. Zhang ◽  
W. Lu
Keyword(s):  
Drinking Water ◽  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Free Water ◽  
Planktonic Cell ◽  
Biofilm Growth ◽  
Bacteria Growth ◽  
Drinking Water Distribution Systems ◽  
Drinking Water Distribution

Biofilm growth in drinking water distribution systems was studied in an annular reactor system which was designed to model the hydraulic conditions in water mains. Experiments were performed with chlorine-free water as well as with different disinfectant (chlorine or chloramine) residuals and different AOC concentrations added to the reactor influent to examine the effect of disinfectant residuals and AOC concentrations on biofilm accumulation and planktonic cell numbers. The dynamic parameters of bacteria growth were calculated in water with different disinfectant (chlorine or chloramine) and the results indicated that monochloramine may be more effective than free chlorine for control of biofilm accumulation.

Determinants of Legionella pneumophila Contamination of Water Distribution Systems: 15-Hospital Prospective Study

1987 ◽  
Vol 8 (9) ◽  
pp. 357-363 ◽  
Author(s):  
Richard M. Vickers ◽  
Victor L. Yu ◽  
S. Sue Hanna ◽  
Paul Muraca ◽  
Warren Diven ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Cold Water ◽  
Physicochemical Characteristics ◽  
Hot Water ◽  
Environmental Study ◽  
Water Tank ◽  
One Year

AbstractWe conducted a prospective environmental study for Legionella pneumophila in 15 hospitals in Pennsylvania. Hot water tanks, cold water sites, faucets, and show-erheads were surveyed four times over a one-year period. Sixty percent (9/15) of hospitals surveyed were contaminated with L pneumophila. Although contamination could not be linked to a specific municipal water supplier, most of the contaminated supplies came from rivers. Parameters found to be significantly associated with contamination included elevated hot water temperature, vertical configuration of the hot water tank, older tanks, and elevated calcium and magnesium concentrations of the water (P < 0.05). This study suggests that L pneumophila contamination could be predicted based on design of the distribution system, as well as physicochemical characteristics of the water.

scholarly journals Design Aspects, Energy Consumption Evaluation, and Offset for Drinking Water Treatment Operation

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1772
Author(s):  
Saria Bukhary ◽  
Jacimaria Batista ◽  
Sajjad Ahmad
Keyword(s):  
Drinking Water ◽  
Energy Consumption ◽  
Water Treatment ◽  
Carbon Emissions ◽  
Water Distribution ◽  
Net Present Value ◽  
Treatment Plant ◽  
Drinking Water Treatment ◽  
Solar Pv ◽  
Pv System

Drinking water treatment, wastewater treatment, and water distribution are energy-intensive processes. The goal of this study was to design the unit processes of an existing drinking water treatment plant (DWTP), evaluate the associated energy consumption, and then offset it using solar photovoltaics (PVs) to reduce carbon emissions. The selected DWTP, situated in the southwestern United States, utilizes coagulation, flocculation, sedimentation, filtration, and chlorination to treat 3.94 m3 of local river water per second. Based on the energy consumption determined for each unit process (validated using the plant’s data) and the plant’s available landholding, the DWTP was sized for solar PV (as a modeling study) using the system advisor model. Total operational energy consumption was estimated to be 56.3 MWh day−1 for the DWTP including water distribution pumps, whereas energy consumption for the DWTP excluding water distribution pumps was 2661 kWh day−1. The results showed that the largest consumers of energy—after the water distribution pumps (158.1 Wh m−3)—were the processes of coagulation (1.95 Wh m−3) and flocculation (1.93 Wh m−3). A 500 kW PV system was found to be sufficient to offset the energy consumption of the water treatment only operations, for a net present value of $0.24 million. The net reduction in carbon emissions due to the PV-based design was found to be 450 and 240 metric tons CO2-eq year−1 with and without battery storage, respectively. This methodology can be applied to other existing DWTPs for design and assessment of energy consumption and use of renewables.

scholarly journals Water quality event detection and customer complaint clustering analysis in distribution systems

2012 ◽  
Vol 12 (5) ◽  
pp. 580-587 ◽  
Author(s):  
Stephen Mounce ◽  
John Machell ◽  
Joby Boxall
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Source ◽  
Water Quality Monitoring ◽  
Water Utility ◽  
Drinking Water Distribution ◽  
Historic Data

Safe, clean drinking water is a foundation of society and water quality monitoring can contribute to ensuring this. A case study application of the CANARY software to historic data from a UK drinking water distribution system is described. Sensitivity studies explored appropriate choice of algorithmic parameter settings for a baseline site, performance was evaluated with artificial events and the system then transferred to all sites. Results are presented for analysis of nine water quality sensors measuring six parameters and deployed in three connected district meter areas (DMAs), fed from a single water source (service reservoir), for a 1 year period and evaluated using comprehensive water utility records with 86% of event clusters successfully correlated to causes (spatially limited to DMA level). False negatives, defined by temporal clusters of water quality complaints in the pilot area not corresponding to detections, were only approximately 25%. It was demonstrated that the software could be configured and applied retrospectively (with potential for future near real time application) to detect various water quality event types (with a wider remit than contamination alone) for further interpretation.

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