Chloramine Concentrations within Distribution Systems and Their Effect on Heterotrophic Bacteria, Mycobacterial Species, and Disinfection Byproducts

2021 ◽  
Vol 205 ◽  
pp. 117689
Author(s):  
Stacy Pfaller ◽  
Dawn King ◽  
Jatin H. Mistry ◽  
Matthew Alexander ◽  
Gulizhaer Abulikemu ◽  
...  
Keyword(s):  
Distribution Systems ◽  
Heterotrophic Bacteria ◽  
Disinfection Byproducts ◽  
Mycobacterial Species

An experimental study for chlorine residual and trihalomethane formation with rechlorination

2007 ◽  
Vol 55 (1-2) ◽  
pp. 307-313 ◽  
Author(s):  
J. Lee ◽  
D. Lee ◽  
J. Sohn
Keyword(s):  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Disinfection Byproducts ◽  
Correction Coefficient ◽  
Empirical Power ◽  
Chlorine Residual ◽  
Chlorine Decay ◽  
And Control ◽  
Large Distribution

Maintenance of adequate chlorine residuals and control of disinfection byproducts (DBPs) throughout water distribution systems is currently an important issue. In particular, rechlorination can be a powerful tool in controlling adequate chlorine residual in a large distribution system. The patterns of chlorine decay and formation of DBPs due to rechlorination are different from those of chlorination; chlorine decay is slower and trihalomethane (THM) formation is lower with rechlorination. The present study evaluates whether existing predictive models for chlorine residual and THM formation are applicable in the case of rechlorination. A parallel first-order decay model represents the best simulation results for chlorine decay, and an empirical power function model (modified Amy model) with an introduced correction coefficient (ϕ1, ϕ2) is more suitable to THM formation.

scholarly journals Occurrence of Mycobacteria in Water Treatment Lines and in Water Distribution Systems

2002 ◽  
Vol 68 (11) ◽  
pp. 5318-5325 ◽  
Author(s):  
Corinne Le Dantec ◽  
Jean-Pierre Duguet ◽  
Antoine Montiel ◽  
Nadine Dumoutier ◽  
Sylvie Dubrou ◽  
...  
Keyword(s):  
Drinking Water ◽  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution System ◽  
Sand Filtration ◽  
Mycobacterial Species ◽  
Slow Sand Filtration ◽  
Drinking Water Distribution ◽  
Rapid Sand Filtration

ABSTRACT The frequency of recovery of atypical mycobacteria was estimated in two treatment plants providing drinking water to Paris, France, at some intermediate stages of treatment. The two plants use two different filtration processes, rapid and slow sand filtration. Our results suggest that slow sand filtration is more efficient for removing mycobacteria than rapid sand filtration. In addition, our results show that mycobacteria can colonize and grow on granular activated carbon and are able to enter distribution systems. We also investigated the frequency of recovery of mycobacteria in the water distribution system of Paris (outside buildings). The mycobacterial species isolated from the Paris drinking water distribution system are different from those isolated from the water leaving the treatment plants. Saprophytic mycobacteria (present in 41.3% of positive samples), potentially pathogenic mycobacteria (16.3%), and unidentifiable mycobacteria (54.8%) were isolated from 12 sites within the Paris water distribution system. Mycobacterium gordonae was preferentially recovered from treated surface water, whereas Mycobacterium nonchromogenicum was preferentially recovered from groundwater. No significant correlations were found among the presence of mycobacteria, the origin of water, and water temperature.

The Effects of Flushing on Water Quality and Biofilm Biomass in Different Daily Flow Patterns of Distribution System

2014 ◽  
Vol 1030-1032 ◽  
pp. 330-333
Author(s):  
Ze Bing Zhu ◽  
Chen Guang Wu ◽  
Dan Zhong ◽  
Yi Xing Yuan ◽  
Li Li Shan ◽  
...  
Keyword(s):  
Water Quality ◽  
Flow Velocity ◽  
Distribution System ◽  
Distribution Systems ◽  
Heterotrophic Bacteria ◽  
Flow Patterns ◽  
Low Flow ◽  
Biofilm Growth ◽  
Patterns Of Distribution ◽  
Increase Flow Velocity

We studied the effects of flushing on water quality and biofilm biomass in different daily flow patterns of distribution system. After building up steady biofilm layers in two flow velocity (0.25 m/s and 0.65 m/s) distribution systems consisting of PE pipe, then flushed by stepwise increased flow velocity. An increase flow velocity caused an immediate increase in turbidity and heterotrophic bacteria of water as a result of detachment of biofilms in the pipes, especially in low flow patterns distribution system. Three days later after flushing, water quality of two systems were generally lower and more stable than before flushing. Flushing strategies only limited biofilm growth to a certain extent and did not completely eliminate microorganisms from the systems.The low flow velocity distribution system was easily being disturbed by flushing.

Microbial Quality of Drinking Water in Some Finnish Distribution Systems

1993 ◽  
Vol 27 (3-4) ◽  
pp. 151-154 ◽  
Author(s):  
Kirsti Lahti
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Surface Water ◽  
Distribution Systems ◽  
Heterotrophic Bacteria ◽  
Biochemical Tests ◽  
Gram Negative ◽  
Total Coliforms ◽  
Groundwater Supply ◽  
Sampling Points ◽  
Faecal Streptococci

The occurrence of heterotrophic bacteria, Pseudomonas aeruginosa, Aeromonas, total coliforms, faecal streptococci, molds and yeasts in distribution systems of two surface water, two artificial groundwater and two groundwater supplies was examined three times during one year. All water samples studied were free of Pseudomonas aeruginosa and faecal streptococci in 100 ml. Total coliforms were detected in water distributed from one groundwater supply. Aeromonas hydrophila/caviae in the concentration range <1 - 32 cfu/100 ml also occurred in distributed water from the same supply. Molds and yeasts were frequently found in piped water from all watenvorks. The concentration of molds exceeded 100 cfu/100 ml in two sampling points. The differences in heterotrophic plate counts were greater between different sampling points of the same surface water supplies than between waterworks with different raw water origins. Over 80 % of the isolated strains of heterotrophic bacteria from different sampling locations were gram-negative and 57 % were oxidase-negative. The identified gram-negative strains belonged to the genera Pseudomonas, Moraxella, Alcaiigenes and Flavobacterium. The majority of strains (64 %) remained unidentified with the biochemical tests used.

Occurrence of heterotrophic bacteria and fungi in cold and hot water distribution systems using water of different quality

1995 ◽  
Vol 41 (12) ◽  
pp. 1088-1094 ◽  
Author(s):  
Outi M. Zacheus ◽  
Pertti J. Martikainen
Keyword(s):  
Surface Water ◽  
Water Samples ◽  
Distribution Systems ◽  
Heterotrophic Bacteria ◽  
Cold Water ◽  
Hot Water ◽  
Thermophilic Fungi ◽  
Cell Counts ◽  
Bacteria And Fungi ◽  
Water Plants

The microbiological quality of cold and hot water samples of 67 Finnish buildings was studied. Most of the buildings were apartment buildings receiving their cold water from municipal groundwater or surface water plants. Disinfection with chlorine was applied in all the surface water plants and 33% of the groundwater plants. Water samples in buildings were taken from incoming cold water, from the hot water main just before and after the heat exchanger, and from a tap or shower in an apartment. The viable counts of mesophilic bacteria and fungi and total cell counts were higher in cold than in hot water samples. In hot water, the microbial counts were higher in samples from taps and showers than from the mains. In taps and showers, the decrease in hot water temperature probably increased the microbial numbers. Thermophilic bacteria appeared with high numbers in all the hot water samples, but thermophilic fungi were found in only one sample. Bacterial biomass and mean cell volume were greater in processed surface water than in processed groundwater samples. Disinfection with chlorine reduced the viable plate counts, although the chlorine concentration was extremely low in the water samples studied.Key words: heterotrophic bacteria, fungi, distribution system, groundwater, surface water.

Molecular characterization of bacteria inhabiting a water distribution system simulator

2003 ◽  
Vol 47 (5) ◽  
pp. 149-154 ◽  
Author(s):  
J.W. Santo Domingo ◽  
M.C. Meckes ◽  
J.M. Simpson ◽  
B. Sloss ◽  
D.J. Reasoner
Keyword(s):  
16S Rdna ◽  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution System ◽  
Heterotrophic Bacteria ◽  
Feed Water ◽  
Ammonia Oxidizing Bacteria ◽  
16S Rdna Pcr ◽  
The Impact

The objective of this study was to monitor the impact of chlorination and chloramination treatments on heterotrophic bacteria (HB) and ammonia-oxidizing bacteria (AOB) inhabiting a water distribution system simulator. HB densities decreased while AOB densities increased when chloramine was added. AOB densities decreased below detection limits after the disinfection treatment was switched back to chlorination. The presence of AOB was confirmed using a group-specific 16S rDNA-PCR method. 16S rDNA sequence analysis showed that most bacterial isolates from feed water, discharge water, and biofilm samples were α-Proteobacteria or β-Proteobacteria. The latter bacterial groups were also numerically dominant among the sequences recovered from water and biofilm 16S rDNA clone libraries. The relative frequency of each culturable bacterial group was different for each sample examined. Denaturing gradient gel electrophoresis analysis of total community 16S rDNA genes showed notable differences between the microbial community structure of biofilm samples and feed water. The results of this study suggest that disinfection treatments could influence the type of bacterial community inhabiting water distribution systems.

scholarly journals A biochemical multi-species quality model of a drinking water distribution system for simulation and design

2013 ◽  
Vol 23 (3) ◽  
pp. 571-585 ◽  
Author(s):  
Krzysztof Arminski ◽  
Tomasz Zubowicz ◽  
Mietek A. Brdys
Keyword(s):  
Drinking Water ◽  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Heterotrophic Bacteria ◽  
Ammonia Oxidizing Bacteria ◽  
Large Set ◽  
Monitoring And Control ◽  
Quality Model ◽  
Drinking Water Distribution

Abstract Drinking Water Distribution Systems (DWDSs) play a key role in sustainable development of modern society. They are classified as critical infrastructure systems. This imposes a large set of highly demanding requirements on the DWDS operation and requires dedicated algorithms for on-line monitoring and control to tackle related problems. Requirements on DWDS availability restrict the usability of the real plant in the design phase. Thus, a proper model is crucial. Within this paper a DWDS multi-species quality model for simulation and design is derived. The model is composed of multiple highly inter-connected modules which are introduced to represent chemical and biological species and (above all) their interactions. The chemical part includes the processes of chloramine decay with additional bromine catalysis and reaction with nitrogen compounds. The biological part consists of both heterotrophic and chemo-autotrophic bacteria species. The heterotrophic bacteria are assumed to consume assimilable organic carbon. Autotrophs are ammonia oxidizing bacteria and nitrite oxidizing bacteria species which are responsible for nitrification processes. Moreover, Disinfection By-Products (DBPs) are also considered. Two numerical examples illustrate the derived model’s behaviour in normal and disturbance operational states.

Review / SynthèseA review of drinking-water-associated endotoxin, including potential routes of human exposure

2002 ◽  
Vol 48 (7) ◽  
pp. 567-587 ◽  
Author(s):  
William B Anderson ◽  
Robin M Slawson ◽  
Colin I Mayfield
Keyword(s):  
Drinking Water ◽  
Distribution Systems ◽  
Water Distribution ◽  
Tap Water ◽  
Disinfection Byproducts ◽  
Potential Health ◽  
Biofilm Growth ◽  
Disinfection Byproduct ◽  
Drinking Water Distribution Systems ◽  
Drinking Water Distribution

In the past decade efforts have been made to reduce the formation of harmful disinfection byproducts during the treatment and distribution of drinking water. This has been accomplished in part by the introduction of processes that involve the deliberate encouragement of indigenous biofilm growth in filters. In a controlled environment, such as a filter, these biofilms remove compounds that would otherwise be available as disinfection byproduct precursors or support uncontrolled biological activity in distribution systems. In the absence of exposure to chlorinated water, most biofilm bacteria are gram negative and have an outer layer that contains endotoxin. To date, outbreaks of waterborne endotoxin-related illness attributable to contamination of water used in hemodialysis procedures have been only infrequently documented, and occurrences linked to ingestion or through dermal abrasions could not be located. However, a less obvious conduit, that of inhalation, has been described in association with aerosolized water droplets. This review summarizes documented drinking-water-associated incidents of endotoxin exposure attributable to hemodialysis and inhalation. Typical endotoxin levels in water and conditions under which substantial quantities can enter drinking water distribution systems are identified. It would appear that endotoxin originating in tap water can be inhaled but at present there is insufficient information available to quantify potential health risks.Key words: endotoxin, lipopolysaccharide, LPS, drinking water.

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